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alaeoecology 252 (2007) 93–117www.elsevier.com/locate/palaeo

Palaeogeography, Palaeoclimatology, P

Conodont diversity and evolution through the latest Permianand Early Triassic upheavals

Michael J. Orchard

Geological Survey of Canada, 101-605 Robson St., Vancouver, B.C., Canada V6B 5J3

Accepted 30 November 2006

Abstract

A study of latest Permian and Early Triassic multielement conodonts identifies eight steps in their evolutionary history duringan interval when Earth's biosphere was highly stressed. These steps are: 1) gradual decline of families and genera through theChanghsingian (up to the late Griesbachian); 2) conodont biofacies change and extinction of Tethyan endemic species close to thePermian–Triassic Boundary (PTB); 3) faunal turnover with extinction and origination in the late Griesbachian; 4) initial radiationin gondolellids and diversification in apparatuses during the Dienerian; 5) explosive radiation in the early–middle Smithian; 6) majorextinction in the late Smithian; 7) major radiation early in the Spathian; 8) gradual turnover and decline in the late Spathian throughearly Anisian. Conodontophorids were reduced from five families at the beginning of the Changhsingian to three by the PTB, and totwo late in the Griesbachian. From the Changhsingian to the late Griesbachian, there was a single multielement apparatus representedin the Gondolellidae, whereas by the Olenekian there were at least twelve. Given absolute age constraints, the conodont recovery inthe aftermath of the PTB was extraordinary. Conodont evolution during the Dienerian remains obscure but was very significant interms of changes in multielement apparatuses. In spite of Induan extinctions, generic diversity generally increased from the PTB up tothe late Smithian. In terms of species, genera, and multielement apparatuses, the acme of Triassic conodonts was in the middleSmithian, and the biggest extinction was in the late Smithian. After this extinction, generic and apparatus diversity quickly returned tohigh levels, marking a significant Spathian recovery. Gradual decline characterized the late Spathian and persisted into the earlyAnisian. A synthetic summary of the temporal distribution and proposed relationships amongst all known Lower Triassic conodontsprovide an improved foundation for biostratigraphic and biochronologic studies. Extinction and radiation trends correlate well withsea-level changes and sequence boundaries: faunal turnovers correspond to lowstands in the late Griesbachian, late Smithian, and lateSpathian, and radiations correspond to transgressions in the early Griesbachian, early Smithian, and early Spathian. The trends alsocorrelate with perturbations in the carbon cycle, with Lower Triassic δ13C minima corresponding to extinction and faunal turnover,and positive values generally occurring during radiations. However, Middle Triassic recovery of marine benthos follows a positivemaxima and an overall decline in conodont diversity. New taxa Borinella chowadensis, B. megacuspa, Neogondolella griesbachensis,and N. mongeri are described.Crown Copyright © 2007 Published by Elsevier B.V. All rights reserved.

Keywords: Conodonts; Lower Triassic; Evolution; Extinction; Multielement taxonomy; Permian–Triassic Boundary

E-mail address: [email protected].

0031-0182/$ - see front matter. Crown Copyright © 2007 Published by Elsdoi:10.1016/j.palaeo.2006.11.037

1. Introduction

Permian–Triassic Boundary (PTB) events profound-ly impacted Earth's biota, and conodonts were no

evier B.V. All rights reserved.

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http://dx.doi.org/10.1016/j.palaeo.2006.11.037

94 M.J. Orchard / Palaeogeography, Palaeoclimatology, Palaeoecology 252 (2007) 93–117

exception. However, there have been different inter-pretations of how severe this was for the group. In orderto put this in perspective, the evolutionary history ofconodonts during the latest Permian and Lower Triassicneeds clarification. The intent of this study is to docu-ment the record of the group over the longer period inorder to understand how significant the PTB extinctionswere and how conodonts responded in the aftermath.This study incorporates a conodont multielementtaxonomy (Orchard, 2005), a novel approach in as-sessing evolutionary pathways and the extent of faunalchange during the Lower Triassic that adds a newdimension to our understanding of conodont history.

It appears that conodonts were in long-term declineduring the late Paleozoic and by the latest Permian fewconodont genera remained. Representatives of theconodont families Gondolellidae, Anchignathodontidae,and Ellisoniidae survived up to, and crossed the PTBwithout major change. Two other families, representedby the genera Iranognathus and Vjalavognathus, ap-parently disappeared during the early Changhsingian.Accounts of the history of PTB conodont extinction andLower Triassic recovery have been presented (Clark,1987; Kozur, 1990a), but they have not considered theevolution of the conodontophorid apparatus. Lack ofmultielement data has also hampered our understandingof evolutionary pathways amongst Lower Triassicconodonts, which has been based principally on themorphology of the P1 elements of these apparatuses.However, a typical gondolellid apparatus containedfifteen elements of seven different types (Orchard,2005), which adds considerable scope for evolutionarychange in conodonts.

A nomenclatural disconnect in conodont taxonomyexaggerates the changes in conodonts across the PTB.Permian gondolellids are often referred to Clarkinawhereas in the Triassic they have been traditionally calledNeogondolella. Similarly, Merrillina and Stepanovites ofthe Permian are closely allied, if not identical, to somespecies assigned to Neospathodus and Ellisonia in theTriassic. The genus Clarkina was introduced by Kozur(1990b) for the Upper Permian gondolellids thatdisappeared near the PTB in Tethyan sections (e.g. atthe base of bed 27 at Meishan, China; Zhang et al., 1996,p. 61). ‘True’ Neogondolella was assumed to have newlyemerged from different origins in the Middle Triassic. Infact, ‘Clarkina’ did not become extinct but disappearedfrom some sections due to a change in facies (Orchard andKrystyn, 1998, Fig. 4C). Elsewhere, e.g. in Tibet (Orchardet al., 1994) and Spiti (Orchard and Krystyn, 1998,Figs. 4A, B), similar Neogondolella faunas dominateearly Induan strata. Data from high northern latitudes

(Dagis, 1984; Klets, 1998; Klets and Yadrenkin, 2001),and from Panthalassan terranes (Orchard, 1981), showthatNeogondolella occurs throughout the Lower Triassic.

The Anchignathodontidae began to evolve rapidly inthe latest Permian and continued to do so in the earlyInduan with diversification in both Hindeodus and itsderivative Isarcicella (Nicoll et al., 2002; Perri andFarabegoli, 2003). Amongst the Ellisoniidae, themultielement differentiation of the constituent generais unclear but representatives on both sides of the PTBare similar, and the group continued into the Olenekian.For the gondolellids and anchignathodontids, a majorfaunal turnover occurred at the end of the lower Induan,or Griesbachian. At that time, the ancient anchignatho-dontid stock virtually disappeared and a branch of thegondolellid stock evolved into the archetypical LowerTriassic conodont genus Neospathodus.

By the lowermost Olenekian, or early Smithian,many more conodont species are known, but the mag-nitude of the radiation has been obscured by the com-mon use of a single genus, Neospathodus, for most ofthese Lower Triassic species. Orchard (2005) describedfifteen different multielement reconstructions of LowerTriassic gondolellid genera, nine of which were former-ly assigned to Neospathodus. The derivation of theseOlenekian taxa from a single Induan Neogondolellaapparatus represents a profound evolutionary develop-ment. Evolution of the multielement apparatus is a re-markable aspect of the Early Triassic conodont recoveryand radiation and poses a substantial taxonomic chal-lenge. The patterns of extinctions and recoveries basedon both multielement and species-level diversity, andtheir correlation with environmental change, is exam-ined in this paper.

2. The latest Permian and Early Triassicconodont record

The character, relationships, and history of fivefamilies and many subfamilial groups of Changhsingianthrough Olenekian conodonts are described below.These represent most taxa, both described and unde-scribed, known to the author. Throughout this account,first mention of a genus–species is given in its originalform, with author. Quotation marks indicate that thegenus assignment has subsequently changed: Figs. 1–3incorporate current generic usage.

2.1. The family Anchignathodontidae

This family includesHindeodus and its Early Triassicderivatives Isarcicella and Sweetohindeodus. Thirty-

Fig. 1. The temporal distribution of Lower Triassic conodonts of the subfamilies Neogondolellinae, Scythogondolellinae, Gladigondolellinae,and Mullerinae showing probable and conjectural relationships. Abbreviations: Bo. = Borinella; Cb. = Columbitella; Gu. = Guangxidella; Ng =Neogondolella; Sc. = Scythogondolella; Wp. = Wapitiodus.

95M.J. Orchard / Palaeogeography, Palaeoclimatology, Palaeoecology 252 (2007) 93–117

Fig. 2. The temporal distribution of Lower Triassic conodonts of the subfamilies Neogondolellinae, Novispathodinae and Cornudininae, andthe family Anchignathodontidae showing probable and conjectural relationships. Abbreviations: Ch. = Chiosella; Eu. = Eurygnathodus; Ic. =Icriospathodus; Ng = Neogondolella; Ns. = Neospathodus; Nv. = Novispathodus; Tr. = Triassospathodus.


Fig. 3. The temporal distribution of Lower Triassic conodonts of the family Ellisoniidae showing probable and conjectural relationships.Abbreviations: Ell. = Ellisonia; Hd. = Hadrodontina; Me. = Merrillina; Pch. = Parachirognathus; Pcl. = Pachycladina.


five years ago, only a single species of the first twogenera, respectively ‘Anchignathodus’ typicalis Sweetand ‘Spathognathodus’ isarcicus Huckriede, wereidentified in PTB strata. The impetus generated byresearch on the PTB has now resulted in the differen-tiation of at least twenty-five species of Hindeodus andIsarcicella. Twenty-two of these occur in the earlyInduan, and thirteen in the latest Permian; ten speciesrange across the PTB. This rapid evolution in theanchignathodontids apparently began after the firstpulse of animal extinction in the late Changhsingian(bed 24e at Meishan) and continued uninterrupted

through the early Induan until the virtual extinction ofthe family in the late Griesbachian. Recent work by Wu(2005), based on a reassessment of conodont illustra-tions from the literature, added an additional fourteennew species and five new subspecies of Hindeodus fromthe PTB beds of Meishan, Shangxi, and Kashmir, butmost of these new taxa are insufficiently established.

The following list of species (excluding those of Wu,2005) arranged in the order of their introduction reflectsboth an evolution in nomenclature and progressiverefinement in temporal resolution: ‘Spathognathodus’isarcicus Huckriede, Hindeodus typicalis Sweet,


H. latidentatus Kozur, Mostler and Rahimi-Yazd,‘Anchignathodus’ turgidus Kozur, Mostler and Rahimi-Yazd, ‘A.’ parvus Kozur and Pjatakova, Isarcicellastaeschei Dai and Zhang, ‘A.’ anterodentatus Dai, Tianand Zhang, H. postparvus Kozur, H. changxingensisWang, Is? prisca Kozur, H. parvus erectus Kozur,H. praeparvus Kozur, H. sosioensis Kozur, H. n. sp. AOrchard and Krystyn, H. inflatus Nicoll, Metcalfe andWang, H. eurypyge Nicoll et al., H. sp. A Nicoll et al.,H. pisai Perri and Farabegoli, I. lobata Perri andFarabegoli, I. inflata Perri and Farabegoli, I. peculiarisPerri and Farabegoli, H. altus Kozur, H. bicuspidatusKozur, and H. magnus Kozur (=H. humilis Wu). Anadditional probable Hindeodus species, described asNeospathodus primitivusMei, occurs in the basal Induanof Selong, Tibet. Sweetohindeodus bidentatus Kozur andS. tridentatus Kozur from the isarcica Zone of westernSicily are also short-ranging members of this group(Kozur, 1996). The few multielement apparatuses de-scribed for Hindeodus spp. are similar (cf. Ellisoniateicherti Sweet).

The details of the anchignathodontid extinction havenot been well documented. Kozur (1998, p. 147) statesthat all hindeodid conodonts disappeared at the top of theGangetian (=Griesbachian) Stage, corresponding to thetop of the postparvus-sosioensis Zone. In the CanadianArctic, no representatives remain in the latest Griesba-chian zone of Bukkenites strigatus. In Guryul Ravine,Kashmir (Kapoor, 1996) and Spiti (Orchard and Krystyn,1998), the stock occurs through the Ophiceras tibeticumZone or slightly higher. In the southern Alps, Perri andFarabegoli (2003) showed the members of the groupdisappearing in a progressive fashion through the MazzinMember of the Werfen Formation. The group occursthrough bed 30 at Meishan, China (Zhang et al., 1996).There was clearly a continual turnover at the species levelwithin this family throughout the early Induan.

2.2. The family Gondolellidea

2.2.1. The subfamily NeogondolellinaeNeogondolella has a conservative apparatus

(Orchard and Rieber, 1999) that characterizes membersof the subfamily Neogondolellinae (Fig. 1). This ap-paratus, which is recognized in the type species of thegenus, N. mombergensis Tatge, does not change sig-nificantly from the Middle Permian through the MiddleTriassic. As such, it constitutes the rootstock for mostTriassic conodonts.

An account of latest Permian species of ‘Clarkina’was given by Mei et al. (1998) and Wu (2005) for theChanghsingian at Meishan, China, and by Kozur (2004,

2005) for the Dorashamian of Iran. Cool-water gondo-lellids have been discussed by Kozur and Mostler(1996), Mei (1996), and Kozur (2005). A total of about30 species are differentiated in the Late Permian zhangithrough meishanensis zones of Iran (Kozur, 2005). Ofthese, few occur throughout the interval and typically afew species appear and disappear in each interveningzone. At the base of the meishanensis Zone, five speciesdisappear, five range up from the preceding iranicaZone, and six new species appear, all of which –‘Clarkina’ meishanensis Zhang, Lai, Ding, Wu and Liu,‘C.’ orchardi Mei, Neogondolella kazi Orchard,N. nassichuki Orchard, N. taylorae Orchard, andN. tulongensis Tian – range into early Induan of Tibetand Spiti (Orchard et al., 1994; Orchard and Krystyn,1998). Of the nine species reported from the upperChangshing Limestone by Mei et al. (1998), two(‘Clarkina’ zhejiangensis Mei, ‘C.’ meishanensis) areknown to extend into the Triassic (Orchard and Krystyn,1998), but not all of the remaining seven species occuras high as the meishanensis Zone. Seven additionalPermian species from Meishan (Wu, 2005) are toopoorly established to consider here. Five neogondolelli-nid species are found only in cool-water Changhsingianfaunas (includes ‘Clarkina’ procerocarinata Kozur, ‘C.’sheniMei, ‘C.’ sosioensis Gullo and Kozur), and two ofthese (‘Gondolella’ carinataClark, ‘G.’ planataClark), arealso typical Triassic species (Kozur, 2005). Survival ratesacross the PTB are thus seven out of 12 neogondolellinidspecies from Iran, or about half of the total species from allregions. This faunal turnover is not exceptional, andgondolellid diversity in the latest Permian and earliestTriassic is seen to be comparable. In fact, themeishanensisZone appears to be a time of increased speciation. Thevirtual disappearance of all gondolellids at the PTB inMeishan occurs because of a change in facies and not, asWu (2005) proposes, because of a major extinction event.

The diverse early Induan Neogondolella populationis well known from Spiti and Tibet (Orchard et al., 1994;Mei, 1996; Orchard and Krystyn, 1998), although thereis no modern account of contemporaneous NorthAmerican neogondolellinid faunas such as those thatincluded the type species of N. carinata and N. planata.The basal Induan fauna (Fig. 1) constitutes the oldest ofthree Induan Neogondolella-based zones differentiatedby Orchard (in Orchard and Krystyn, 1998), and showsthat the meishanensis Zone in Spiti, which therecorresponds to the parvus — lower staeschei Zone,straddles the PTB. Younger Induan faunas containN. krystyni Orchard, which represents the first Induaninnovation (see below), as well as more conserva-tive elements such as the lanceolate Neogondolella


griesbachensis n. sp. (see Taxonomic notes), whichprobably developed from N. orchardi in the latestGriesbachian (ammonoid zone of Bukkenites strigatusin the Canadian Arctic). In younger, Dienerian strata ofthe allochthonous Cache Creek oceanic terrane inBritish Columbia (Orchard, 1981), relatively commonderivative gondolellids are referred to Neogondolellamongeri n. sp. (see Taxonomic notes). Elements of thelong-ranging N. carinata are known as high as theSmithian in the Canadian Arctic and Yukon Territories(author's collections) and in Siberia (Dagis, 1984).

Several lanceolate Neogondolella species are reportedfrom the lower OlenekianHedenstroemia Zone in Siberia(Dagis, 1984; Klets and Yadrenkin, 2001): N. jakutensisDagis, N. composita Dagis, N. altera Klets andYadrenkin, and N. siberica Dagis (which may be relatedto Borinella, see below). This stock may well have givenrise to most Spathian Neogondolella species, althoughdetails of the succession are not well known and it ispossible that a separate origin could lie within speciesassigned to Borinella (Fig. 1).

Three similar Neogondolella species are found inlower Spathian strata in California and British Colum-bia. These are differentiated on the basis of platformshape and blade characteristics: Neogondolella n. sp. Chas a pointed posterior platform and terminal cusp;Neogondolella n. sp. D has a rounded posterior platformand brim surrounding the cusp; and Neogondolellan. sp. E has partly sinuous platform margins. Each ofthese species produced successor species in the mid-Spathian (Fig. 1). Through reduction in the anteriorplatform, Neogondolella n. sp. C may have given rise toa Canadian species Neogondolella n. sp. K, and to theSiberian species N. amica Klets and N. captica Klets.The Pakistan species Neogondolella elongata Sweet,which is common in the USA (Orchard and Tozer,1997) and is now referred to Columbitella based onmodifications to its apparatus (Orchard, 2005).N. paragondolaelliformis Dagis from Siberia mayhave a similar origin but it has a stronger cusp likethose regarded as derivatives of Neogondolella n. sp. D(Fig. 1).

Neogondolella n. sp. D may have been the progen-itor of forms characterized by a relatively high carina–blade as represented first by N. jubata Sweet from theSalt Range. Additional Spathian species that share thisfeature are Neogondolella n. sp. G from Canada, theSiberian Gondolella shevyrevi Kozur and Mostlerand N. taimyrensis Dagis, and the TranscaucasianN. dolpanae Balini, Gavrilova and Nicora. The firsttwo of these species have a blade of small fused den-ticles like that of the more elongate N. ex gr. regalis of

the later Spathian and Anisian. A contemporary of thelatter species, Neogondolella n. sp. H, which resemblesboth the older N. altera and the Middle Triassic N. exgr. constricta, may have arisen from Neogondolella n.sp. C or D (Fig. 1). Uncommon forms in Canada witha sinuous platform margin, Neogondolella n. sp. Eand Neogondolella n. sp. F, are homeomorphs ofLadinian Budurovignathus species. The multielementapparatuses of most Spathian Neogondolella specieshave not been described but are thought to be typicalof the genus.

2.2.2. The krystyni–discreta–kummeli lineageBeginning within the Griesbachian staeschei Zone, a

lineage of gondolellids show progressive change in theconfiguration of the axial part (blade–carina–cusp) ofthe pectiniform elements concurrent with reductionin platform development (Orchard, in Krystyn andOrchard, 1996). The first species to show this trend isNeogondolella krystyni, which characterizes an intervalthat spans the Otoceras woodwardi and Ophicerastibeticum zones in Spiti, and corresponds to the upperrange of the anchignathodontids (Orchard and Krystyn,1998, Figs. 5 and 6). N. krystyni is also known fromChaohu, China (Zhao et al., this volume) and theCanadian Arctic (Orchard and Tozer, 1997), demon-strating the widespread nature of the stock. The youngerrepresentatives, Neogondolella discreta Orchard andNeospathodus kummeli Sweet are equally ubiquitous.The latter species, now assigned to SweetospathodusKozur, Mostler, and Krainer, is largely Dienerian in age,but it first appears in the latest Greisbachian StrigatusZone in the Arctic. The species has been recorded withN. cristagalli and N. pakistanensis in Spiti (Garzantiet al., 1995, tbl. 5), which is regarded as an upperDienerian limit for the lineage.

2.2.3. The genera Borinella and GladigondolellaIn the Dienerian, segminipastinate elements character-

ized by a distinct cusp, discrete blade–carinal denticlesthat become higher to the anterior, and a variable but oftennarrow or posteriorly restricted, asymmetrical platform,have been assigned to Gondolella nepalensis Kozur andMostler and subsequently to a new genus ChengyuaniaKozur (1994, September; =Pseudogondolella Kozur). Ayounger derivative, Neogondolella buurensis Dagis, isthe type species of Borinella Budurov and Sudar (1994,June; =Kozurella Budurov and Sudar). Kozur (1990a,p. 395) regarded an intermediate species, Gondolellasweeti Kozur and Mostler, as a senior synonym ofNeogondolella buurensis but the two are here regardedas independent species. Since all these species are


regarded as derivatives of nepalensis, I refer them all toBorinella. This genus seems to have preferred highlatitude pelagic environments for most of its range.

Kozur et al. (1998) suggested thatBorinella nepalensiswas derived from Sweetospathodus kummeli but, al-though both taxa have discrete denticulation, thatdevelopmentwould involve the regeneration of a platformin S. kummeli, a reversal of the trend which produced thespecies. It is thought more likely that the genus evolveddirectly from elongate neogondolellinids through modi-fication of the carina. The multielement apparatus ofBorinella chowadensis n. sp. (see Taxonomic notes) is thesame as that ofNeogondolella, which supports this origin(Fig. 1).

In the late Griesbachian and early Dienerian in theCanadian Arctic and probably Svalbard (Neogondolellasp. of Hatleberg and Clark, 1984) there are specimens ofBorinella? megacuspa n. sp. (see Taxonomic notes) thatmay be the forebears of B. nepalensis (=Neospathoduslabiatus Goel), which appears in the late Dienerian andranges into the lower Smithian in pelagic environmentssuch as those represented in Spiti (L. Krystyn collec-tions). Borinella chowadensis, which occurs in theDienerian of British Columbia, has a less developedplatform than B. sweeti from Pakistan and the lateSmithian B. buurensis. Neogondolella siberica may bean early Olenekian derivative of Borinella.

Borinella largely disappeared at the end of theSmithian, but the anterior blade denticulation that is char-acteristic of the genus is seen again in Tethyan platformelements from the Spathian of Oman (Orchard, 2005),where the faunas are dominated by ‘Neospathodus’ andearly Gladigondolella species. The apparatus of MiddleTriassic ‘Polygnathus’ tethydis Huckriede, the typespecies of Gladigondolella (see Orchard, 2005), doesnot occur in these collections but the P1 elements ofG. exgr. carinata Bender, and perhaps Borinella n. sp. C, arethought to be the first stage in the development ofthat important genus. If Borinella is the root stock forGladigondolella, then it would represent a migration ofthe former into lower latitude environments, as is pos-tulated to have occurred amongst conodonts after the PTBextinction (Kozur, 1998).

2.2.4. The Scythogondolellinae (new)This new subfamily of the Gondolellidae is intro-

duced here to accommodate an array of mostly Smithianspecies formerly assigned to Neogondolella. Kozur(1990b) introduced Scythogondolella for short P1 ele-ments with strongly sculpted upturned platform marginsand a rounded loop surrounding their basal pit, with‘Gondolella’ milleriMüller as the type species. Orchard

(2005) added ‘Gondolella’ mosheri Kozur and Mostlerto the genus based on similar P1 morphology and a newmultielement reconstruction, which differs from thatof Neogondolella in both the P and S2–S4 elements(Orchard, 2005). The first P1 elements that resemblethose of the genus appear in the lower DienerianCandidus Zone in the Canadian Arctic and are assignedto Scythogondolella? n. sp. A. Similar forms were fig-ured by Hatleberg and Clark (1984) from the upperDienerian Siksaken Member of the Vardebukta For-mation, south-western Svalbard, as Neogondolellaelongata Sweet (a Spathian species) and Neospathodussp. B. These elements, like N. discreta, have a strongcusp and carina, and a somewhat reduced platform butthey have a more expanded and rounded loop surround-ing the basal pit. In this respect they resemble someNeospathodus species. It is probable that they were anindependent line emerging fromNeogondolella discreta.A species described as Neogondolella sweeti n. sp. byDagis and Korchinskaya (1989; a homonym of a speciesnamed by Kozur and Mostler, 1976) from the upperInduan of Svalbard may be a link to the Smithian species(Fig. 1).

The type species of Scythogondolella, S. milleri,developed from the slightly older S. mosheri via thetransitional form ‘Gondolella’ milleri parva Kozur andMostler in the late Smithian Tardus Zone (Fig. 1).Scythogondolella mosheri appears to be a paedomorphicdescendant of Scythogondolella? n. sp. B known from theprecedingRomunduri Zone in the CanadianArctic, whichhas a much longer but similarly shaped ovoid platform.There are several other segminiplanate P1 elementsassociated in the Romunduri Zone that have a roundedbasal loop, high carina, and a prominent terminal cusp andthese are tentatively linked to Scythogondolella. Severalappear to lack platform microreticulae. For example,Neogondolella crenulata Mosher has an oblong-shaped,flat platform that is strongly serrated, although some co-occurring and otherwise similar specimens lack orna-mentation. Scythogondolella? n. sp. C has a narrow plat-form and a strongly inclined cusp beneath which theplatform extends posteriorly in later growth stages. In thisway, some specimens of Scythogondolella? n. sp. Cmimic the contemporaneous ‘Gladigondolella’ meekiPaull which, like S.? crenulata, sometimes has acrenulated platform. However, ‘G.’ meeki has a multiel-ement apparatus typical of theMullerinae (see below), notScythogondolella (Orchard, 2005). Neither S.? crenulatanor Scythogondolella? n. sp. C have known multielementapparatuses so their generic assignment is uncertain;the same applies to Scythogondolella? n. sp. D andScythogondolella? n. sp. E from Smithian strata in north-


eastern British Columbia. In common with S. milleri,these new species have narrow, biconvex platforms andprominent, closely spaced carinal denticles. The Scytho-gondolellinae do not range above the Smithian.

2.2.5. The Neospathodus dieneri groupNeospathodus dieneri Sweet is thought to have its

origins in Neogondolella discreta through total platformloss and expansion of the basal cavity. A more directorigin from Sweetospathodus kummeli is thought un-likely in view of the basal configuration of the latter andthe more or less concurrent appearance of the two spe-cies in the latest Griesbachian Strigatus Zone of theArctic (Orchard and Tozer, 1997, p. 677), and elsewhere(e.g. Guryul Ravine, Kashmir, Kapoor, 1996, Fig. 8.4;Taho Limestone, southwest Japan, Musashi et al., 2001;Chaohu, China, Zhao et al., this volume). In some lo-calities (e.g. Narmia, Pakistan, Yin et al., 1996, Fig. 1.1;Spiti composite, Bhatt et al., 1999), S. kummeli doesappear first but the graphic correlation undertaken bySweet (1988) suggests a simultaneous appearance. Thetendency for some derivative Neospathodus species toform narrow platform ledges in later growth stages (seebelow) is a throwback to these roots. The multielementapparatus of N. dieneri has not been described but isthought to be close, at least in early morphotypes, to thatof Neogondolella.

Conodont collections from the Candidus Zone ofthe Dienerian Stage type section in the Canadian Arcticare largely composed of segminate elements with around basal cavity that fall within a broad concept ofNeospathodus dieneri. They show variation in lateralprofile, denticle form, flange development, and relativesize and depth of the basal cavity. In profile, the posteriorbasal margins are weakly to strongly upturned andoccasionally down turned distally. This population isbelieved to represent early diversification in the root-stock leading to several younger lineages. Amongst thevariants are three morphotypes recognized first in col-lections of N. dieneri from Chaohu, China (Zhao et al.,this volume), where they appear in progressivelyyounger beds. Morphotype 1 has a large cusp andleads to N. chii Zhao and Orchard; Morphotype 2 has acusp and penultimate denticle of subequal size, a den-ticulation shared by N. chaohuensis Zhao and Orchard;and Morphotype 3 has a smaller denticle posteriorof the cusp, the beginning of a trend leading toN. pakistanensis Sweet and N. waageni Sweet. OtherDienerian derivatives of N. dieneri include forms withwell developed platform flanges, as in Neospathodussvalbardensis Trammer from the Vardebukta For-mation, Svalbard (Birkenmajer and Trammer, 1975);

forms with a long, down turned anterior process as inNeospathodus concavus Zhao and Orchard, fromChaohu, China; a form assigned to Neospathodus n. sp.T from the Arctic with a large basal cavity and irregulardenticulation; and derivatives characterized by smaller,more numerous denticles, as inNeospathodus biangularisWang and Cao from the late Dienerian of Hubei,China. Several of the derivatives appear confined to theDienerian,whereas others range into the Smithian (Fig. 2).

Neospathodus dieneri (Morphotypes 1–3) is un-common in the Smithian but may range as high as thelate Smithian in Nepal (Belka and Wiedmann, 1996).More common are Smithian derivatives such asNeospathodus n. sp. B from Chaohu, which developedfrom N. chaohuensis through shallowing of the basalcavity, and the similar N. robustus Koike from Malay-sia (Koike, 1982). Neospathodus n. sp. F from Chaohuhas a straight lower-edge profile and resembles theAmerican species originally described as ‘Neoprioniodus’bicuspidatus Müller; the former species has uniformdenticles unlike the latter which has two large posteriordenticles. Neospathodus n. sp. S, from Spiti, has a moredeveloped posterior margin, strongly inclined denticles,and an elongate basal cavity; the same species occurs inthe Smithian Romunduri Zone of the Arctic.

2.2.6. The Neospathodus cristagalli group‘Spathognathodus’ cristagalli Huckriede, the type

species for the genus Neospathodus Mosher, appearedabout the same time as N. dieneri, and may have origi-nated from a common ancestor, or more directly fromSweetospathodus kummeli. The latter origin is suggestedby the character of the basal cavity, which differs from thatof N. dieneri in being shallower and posteriorly elongaterather than round and more deeply excavated. The shortand broad triangular cusp characteristically separatedfrom the anterior denticle sets this species and itsderivatives apart from other Neospathodus species. Theapparatus of a species allied to Neospathodus cristagalliis similar to that of Neogondolella (Orchard, 2005).

Olenekian representatives of Neospathodus ex gr.cristagalli often display considerable posterior elonga-tion of the shallow basal cavity beneath a lengtheningposterior process. At least two such forms are known:Neospathodus n. sp. U, which occurs in Oman andSpiti and has a long, upturned posterior process, andNeospathodus n. sp. V, which is known from Omanand is shorter and has distinctive wedge-shaped denticletips. A further derivative, Neospathodus tongi Zhao andOrchard from Chaohu, has particularly discrete denti-cles. The multielement apparatuses of these youngerspecies are undescribed and may differ from that of


Dienerian N. cristagalli. Neospathodus cristagalli wasrecorded in the late Smithian of Nepal by Belka andWiedmann (1996), but it does not occur in the Spathian(Fig. 2).

2.2.7. The Neospathodus pakistanensis groupThe holotype of Neospathodus pakistanensis Sweet,

which appeared in the late Dienerian, differs from itsprecursor – probably N. dieneri morphotype 3 – inbeing relatively long and having a posteriormost partthat carries additional short denticles above a posteriorbasal cup that is down turned at its end. The holotypeof the broadly contemporaneous and relatively largeNeospathodus novaehollandiea McTavish has a similarround basal cavity and a progressively lower posteriordenticle profile, but differs in having platform flangesand a generally straight lower-margin profile. As origi-nally noted by Sweet (1970), a mid-lateral rib strength-ens with growth in N. pakistanensis and hence theformation of flanges in larger specimens may be antic-ipated. Thus, N. novaehollandiea has been viewed as ajunior synonym of N. pakistanensis by authors whohave implicitly regarded the lower-margin profile as anintraspecific variable (Matsuda, 1983; Nicora, 1991).The posterior down turning in N. pakistanensis, longregarded as a diagnostic feature of the species is, ac-cording to this view, not a critical feature.

Elements from Spiti (Goel, 1977), Kashmir (Matsuda,1983), and Nepal (Nicora, 1991), either combined asN. pakistanensis or differentiated into that species andN. novaehollandiea, display variation in basal cavityoutline from rounded to posteriorly elongate. This wasregarded as ontogenetic variation in the latter species byMcTavish (1973, p. 295, variation VI), although therelatively large holotype of N. novaehollandiea has arounded cavity (R. Nicoll, pers. comm., 2006). It is moreplausible that a round basal cavity (as in ancestralN. dieneri) is the more primitive condition and posteriorelongation of the cavity is an evolutionary trend. Thisappears to be born out in new material from Spiti(L. Krystyn collections). Hence, amongst the specimensassigned to the species pakistanensis and novaehollan-diea two forms can be distinguished based on the shape ofthe basal cavity rather than the lateral profile of theunderside or the degree of platform flange growth. In thisinterpretation, the holotypes of the two species areconspecific and those forms with an elongate basalcavity should be referred to a new species, for whichN. posterolongatus Zhao and Orchard has been intro-duced (Zhao et al., this volume).

‘Kashmirella’ alberti Budurov, Sudar, and Guptafrom the Guryul Ravine, Kashmir (bed 83 of Khunamuh

Formation) is herein thought to be a probable geronticexample of N. pakistanensis in which an accessory nodeis developed on the basal cup. Although the holotype of‘K.’ alberti was stated to come from strata equivalent tothe late Smithian Tardus Zone, it actually came from thebasal bed of the waageni Zone (Matsuda, 1983), of earlySmithian age. Use of ‘Kashmirella’ for all (Budurovet al., 1988) or some (Kozur et al., 1998) species ofNeospathodus in which platform flanges are developedis artificial because several different species developthem in later growth stages.

The proposed development of Neospathodus poster-olongatus from N. pakistanensis at the start of theOlenekian begins a trend of posterior elongation andprocess development (also seen in the N. cristagalligroup) that is thought to lead to N. spitiensis Goel, inwhich the posterior process rivals the anterior one inlength. Early representatives of this lineage were includedin N. waageni by Matsuda (1983) and referred toN. waageni subsp. B by Zhao et al. (2004).

Neospathodus pamirensis Dagis may fall within thevariability of N. spitiensis, as might the holotype ofN. srivastavai Chhabra and Sahni. The North American‘Ctenognathus’ conservativa Müller has a P1 elementin which the denticles are more erect than those inN. spitiensis. These may be a younger or contempora-neous geographic subspecies, or the similarities be-tween the two species may result from convergence. TheAmerican species has been reconstructed as a newmultielement genus, Conservatella Orchard, a memberof the Mullerinae (Orchard, 2005; see below), but thereis as yet no multielement reconstruction for N. spitiensis,which would help resolve the relationship.

Elements referred to Smithodus Budurov, Buryiand Sudar and formerly assigned to Neospathoduslongiusculus Buryi from the Anasiberites beds in south-ern Primorye, Russia, as well as the Romunduri Zone ofthe Canadian Arctic (Mosher, 1973), may have arisenfrom N. pakistanensis through both anterior andposterior growth. No multielement apparatus is knownat present and use of this genus for other Olenekianspecies (including some assigned to the Mullerinae) byBuryi (1997) is untenable.

2.2.8. The Neospathodus waageni groupIn common with Neospathodus dieneri and

N. pakistanensis, N. waageni Sweet has a roundedbasal cavity and is thought to have developed fromone of the former species at the beginning of theOlenekian (Fig. 2). The relative platform dimensions ofthe species lie closest to N. dieneri, and the holotypesof both species have a more clearly upturned posterior


lower margin. On the other hand, the posterior denticleprofile of N. waageni is closer to that of the moreelongate N. pakistanensis and, furthermore, the plat-form flanges seen in later growth stages of the latter(=‘N. novaehollandiae’) appear also in some largecontemporaneous specimens having the length toheight ratio of N. waageni. The profile of the loweredge in all these species appears to vary, as discussedabove.

Neospathodus waageni is a rather variable speciesand even when restricted to forms with rounded basalcavities and platform dimensions like the holotype, sixmorphotypes can be differentiated in Smithian strata:1) those with platform flanges; 2) specimens with inclineddenticles forming an arcuate profile (=N. w. waageni);3) relatively short elements with upright denticles;4) specimens with a relatively large cusp; 5) elementswith two or three markedly short posterior denticles; and6) those with strongly inclined or radiating posteriordenticles (aff. Neospathodus curtus Dagis). In the Muthsection in Spiti (L. Krystyn collections), the order ofappearance of these morphotypes is: 1+2, followed by 3,then 4+5, and finally 6, but all the morphotypes occurtogether in the youngest collections. In the Chaohusections, elements close to Morphotype 3, now assignedto N. waageni eowaageni Zhao and Orchard, are the firstto appear, a little earlier than N. w. waageni. AlthoughSpiti specimens of Morphotype 3 show variation in theirlower-margin profiles, they are judged to fall withinN. w. eowaageni. Neospathodus n. sp. H from Chaohu isanother similar early Smithian species that developedconcurrently.

The multielement apparatus of N. waageni, althoughpresently undescribed, is thought to be the same orsimilar to that of Spathian Novispathodus Orchard.There is no data on the apparatus of any of the alliedspecies, but we know that the apparatus of probablederivatives of N. waageni continued to evolve rapidly(see below).

2.2.9. The subfamily CornudininaeThis subfamily was introduced by Orchard (2005) to

accommodate small Early Triassic pectiniform ele-ments with a large terminal cusp that are associated witha distinctive suite of ramiform elements. Cornudinaand Spathicuspus are constituent genera. Koike (1996)proposed a bi-elemental apparatus for Cornudina fromJapan, but this reconstruction is considered incomplete.The type species of Cornudina Hirschmann, fromthe Middle Triassic of Germany, is associated withelements referred to the form genera ‘Chirodella’,‘Neohindeodella’, and ‘Diplodella’ (Kozur, pers. comm.,

2006) that differ from those of the Lower Triassic formsassigned to Cornudina by Orchard (2005) although theycould be derivatives. The older species may need a newgeneric name. The origin of the Cornudininae may lie inNeospathodus chii, which has a pronounced terminalcusp (see N. dieneri group) but there is no evidence as towhen the typical Spathian apparatus developed. Kozur(2004) suggested that Cornudina evolved from latePermian Merrillina postdivergens but this is notsupported by the presence of an enantiognathiform S1element (cf. chirodelliform in the Middle Triassic) in theapparatus (Orchard, 2005).

P1 elements resembling those of Spathicuspus Or-chard (type species Neospathodus spathi Sweet) and‘Cornudina’ appeared in the Smithian but became morecommon in the Spathian. Older species such as Neos-pathodus n. sp. W (=Neospathodus sp. 1 of Dagis, 1984)from Siberia and Canada, and Neospathodus n. sp. Xfrom Spiti have prominent cusps, round basal cavities,and relatively long blades, and may be the immediateforebears. Neospathodus lenaensis Dagis from Siberiamay be a related derivative. By the Spathian, both‘Cornudina’ and Spathicuspus are associatedwith a seriesof S3–S4 elements with strongly down turned andbackward-curved anterior processes. Several speciesmay occur in the Olenekian because there is a lot ofvariation in the relative length of elements. Similar formsare also known fromSmithian collections from the Arctic,the USA, and Oman, and Spathian species that maybelong here are N. excelsus Wang and Wang from Tibet,and Neospathodus hungaricus Kozur and Mostler.Spathicuspus also resembles early growth stages ofSpathian Cratognathus Mosher, but a relationship is notsupported by multielement data (Koike, 1999; Orchard,2005).

2.2.10. The genera Aduncodina andNeostrachanognathus

These two genera are unusual Early Triassic generacharacterized by the presence of coniform elements intheir apparatus. These bear a resemblance to the P1elements of Cornudina and they may be members of thesame subfamily. Koike (1998) has presented a multiele-ment reconstruction of each genus, but both areincomplete in the present authors' view. Neither apparatushas a typical enantiognathiform S1 element so affinitywith the gondolellids is unclear. However, Neostracha-nognathus Koike includes strongly reduced and flexedconiform elements that could be homologous S1 elements.Also, the genus has a suite of ramiform S elements (e.g.Oncodella obuti Buryi) that strongly resemble those ofthe Cornudininae (Orchard, 2005). Extremely thin, blade-


like elements (cf. Carnian Prioniodella dropla SpasovandGanev)with the gross morphology of Cornudininae Selements also appear in the latest Spathian and may bederived from Neostrachanognathus (Fig. 2); these arereferred to New Genus A.

Aduncodina Ding resembles Ordovician Stracha-nognathus and, in common with Neostrachanognathus,has a suite of denticulate elements, identified as Sc andSb by Koike (1998), with an antero-lateral denticle orprocess that is directed posteriorward at its base, which isa feature of the Cornudininae. Both Aduncodina andNeostrachanognathus were originally described fromSpathian strata but recent data from Chaohu, Chinashows thatAduncodinaDing appears in the late Smithian(Zhao et al., this volume). The coniform P1 elements ofthe present genera may have been derived throughreduction or loss of the anterior process of segminate P1elements with large cusps.

2.2.11. The subfamily MullerinaeSegminate to carminate elements with long dis-

crete denticles and a prominent cusp appear late in theInduan. Similar elements were formerly assigned to‘Ctenognathus’ discreta Müller but based on a multiel-ement reconstruction of an Olenekian example, speciesare now assigned to Discretella Orchard. This genusand other Smithian examples of the subfamily have adistinctive S3 element in the apparatus which developedthrough the posterior migration (to a position adjoiningthe cusp) of the accessory antero-lateral process seen inthe S3 element of ancestral Neogondolella. The dis-tinctive P1 element of Discretella likely evolved fromSweetognathodus kummeli, but changes in the apparatusmay have developed later (Fig. 1).

By the Smithian, there were several distinct multi-element genera that are assigned to the Mullerinae:Discretella, Conservatella Orchard, Guanxidella Zhangand Yang, and a new genus in which the P1 element is‘Gladigondolella’ meeki Paull (not Meekella Orchard,name preoccupied). Smithian P1 elements of Discretellashow variation in denticle length and spacing, relativecusp size, and in lower-edge profile; some are upturnedonly posteriorly, but most are upturned anteriorly too.Forms with more closely spaced denticles resembleConservatella, which itself varies in relative length:Oman specimens are shorter than those known fromNorth America. Conservatella specimens from BritishColumbia have less basal inversion than specimens fromthe lower latitudes. Hence, there is certainly scope fordifferentiating additional species or subspecies in thisgroup. In Nepal, Conservatella has been recorded ashigh as the late Smithian (Belka and Wiedmann, 1996).

Guangxidella was reconstructed as a multielementgenus based on material from Guangxi Province, China(Zhang andYang, 1991; modified byOrchard, 2005). TheP1 element was originally described as Neoprioniodusbransoni Müller (=Neospathodus zharnikovae Buryi),which has a massive terminal cusp, an asymmetric basalcavity, and variable denticle separation. Specimens ofDiscretella that have a large cusp while retaining aposterior process provide linkage between the two genera.At least two species of Guanxidella occur in theRomunduri Zone of the USA: G. bransoni and a similarform, Guanxidella n. sp. A, which is strongly curvedlaterally. Other elements from northeast British Columbiaappear allied to ‘Cratognathus’ robustusWang andWangfrom Tibet and to Neospathodus dronovi Dagis fromSiberia: all have similar asymmetric basal cavities andinclude a denticle posterior to the cusp. These are referredwith question to Guangxidella, although the Canadianspecimens certainly appear to be examples of theMullerinae based on limited ramiform element data.

‘Gladigondolella’ meeki has a carminiplanate P1 ele-ment unlike other members of the subfamily. Thedevelopment of the platform represents a morphologyconvergent with the younger Gladigondolellinae but itsapparatus is different (Orchard, 2005). Like other mem-bers of theMullerinae, it disappeared in the late Smithian.

2.2.12. The genus WapitiodusWapitiodus was introduced by Orchard (2005) for an

apparatus centred on segminate (in early growth stages)to segminiplanate (in late growth stages) P1 elementsthat are associated with a unique apparatus resemblingmost closely members of the Mullerinae, particularlyGuangxidella Zhang and Yang (Orchard, 2005). Thegenus may be related to that group (Fig. 1) but it differsby possessing an S3 element that has an accessoryprocess anterior of the cusp, more like that of ancestralNeogondolella. The holotype of Neospathodus jhelumiChhabra and Sahni may be an example of this genus too.This genus appears to be confined to the Smithian andlacks obvious descendants.

2.2.13. The Novispathodus abruptus stockMost Spathian segminate conodonts are thought to

have their origins in Neospathodus waageni, fromwhich N. pingdingshanensis Zhao and Orchard and laterNovispathodus abruptus Orchard arose (Fig. 2). Thelatter, type species for Novispathodus Orchard, has anapparatus (Koike, 2004; Orchard, 2005) that is differentfrom Neospathodus sensu stricto, although it might bethe same as that of N. waageni. By the middle SpathianN. abruptus had radiated into many independent


species, at least some of which had different appara-tuses. For example, TriassospathodusKozur,Mostler andKrainer is represented by Spathognathodus homeriBender (reconstructed by Orchard, 2005), Neospathodussymmetricus Orchard, and ‘Ctenognathodus’ chionensisBender (reconstructed by Koike, 2004). Kozur et al.(1998, p. 2–3) assigned many other Olenekian species toTriassospathodus based on their P1 elements, but hisreliance on morphological similarity of P1 elements fortaxonomic grouping is basically a traditional form-taxonomic approach and cannot be defended in multiel-ement terms. Further allied species that may be co-genericinclude N. brochus Orchard and N. sosioensis Kozur,Krainer and Mostler. The similar ‘Spathognathodus’gondolelloides Bender, now referred to ChiosellaKozur, may have developed from this group in thelatest Spathian although this has yet to be demonstratedin multielement terms. Two other Spathian species,Neospathodus pusillus Orchard from Oman andN. anhuiensis Ding from China, which share a bladedenticulation composed of numerous small denticles,are tentatively related to the homeri-symmetricus group(Fig. 2).

A separate line from Novispathodus abruptus in-volves progressive reduction of the posterior platformand leads first to Neospathodus curtatus Orchard andthen to N. triangularis Bender (see Orchard, 1995). Thelatter species appear later than similar short elements,characterized as Neospathodus ex gr. brevissimusOrchard, which have larger basal cavities butappear equally widespread and stratigraphically useful.Neospathodus eotriangularis Zhao and Orchard fromChaohu may be related to one or the other lines, as mightNeospathodus n. sp. P, which is known from both Chinaand North America.

A further group of early Spathian derivatives from theN. abruptus stock includes forms in which a subterminalcusp becomes increasingly emphasized. Neospathodustulongensis Tian from China may be an end member ofthis line, which begins with the North American speciesNeospathodus n. sp. Yand passes throughNeospathodus n.sp. Z (Fig. 2); Neospathodus kedahensis Koike fromMalaysia may be an available name for the latter. Thislineage appears related to forms in which the cup andblade become thickened and eventually ornate, as in thedouble-noded P1 element Neospathodus collinsoniSolien, now referred to Icriospathodus Krahl et al. Thisspecies has a distinctive multielement apparatus evidentlyderived from Novispathodus (Orchard, 2005) and isthought to be the end member of a line that also includesN. zaksi Buryi and N. crassatus Orchard, species thatmight have the same apparatus.

2.2.14. The genera Eurygnathodus, Foliella, andPlatyvillosus

Lower Triassic P1 elements with broad platformshave been combined by most authors as species ofPlatyvillosus Clark, Sincavage and Stone, but there areat least three different forms represented and not all arethought to be related. Eurygnathodus costatus Staeschehas aligned nodes and ridges and a broad basal cavityand is believed to have developed from Neospathodusby the broadening of the carinal denticles, as is the casein the younger homeomorph Icriospathodus collinsoni.An unornamented but otherwise similar species,P. hamadai Koike, sometimes co-occurs with E. costatus,as does a more finely ribbed new form, Eurygnathodusn. sp. A. The range of E. costatus is uncertain. Matsuda(1984) found the species in Kashmir, India immedi-ately below the first N. waageni, implying a latestDienerian age, but the specimens of Goel (1977) fromSpiti could be Smithian rather than Dienerian. A likelyprecursor, Platyvillosus paracostatus Wang and Cao,appears in the late Dienerian of China. E. costatusallegedly ranges into the early Spathian strata where itforms part of the assemblage described by Clark et al.(1979) from the Great Basin. However, specimens fromearly Spathian strata may be allied to Icriospathodus,in which case Eurygnathodus probably does not rangeabove the Smithian.

The type species of Platyvillosus, P. asperatus Clark,Sincavage and Stone is apparently restricted to westernUSA and is of early Spathian age. It differs fromE. costatus in bearing irregularly arranged nodes. Itsorigin is uncertain (Fig. 2). It may have evolved fromNeospathodus-like elements, more directly fromSmithianEurygnathodus, or it may be related to ellisonidslike Furnishius. The suggestion (Hirsch, 1994) thatPlatyvillosus evolved from late Smithian Scythogondo-lella milleri seems unlikely.

The third genus, Foliella Budurov and Pantic, isbased on ‘Polygnathus’ gardenae Staesche, whichappears in the late Smithian of the Alpine Werfen facies(Kozur and Mostler, 1982). Like Platyvillosus, it is anodose element but it differs from both the previous twogenera in having a keel and small pit rather than a largebasal cavity. Its origin is unknown but it too may beallied to Furnishius and the Ellisoniidea (see below).

2.3. The family Ellisoniidae

Many representatives of the Ellisoniidae (Fig. 3) arerelatively large, robust elements that favoured shallowwater and tolerated restricted-marine environments.They have received less attention than the gondolellids


and, although several multielement reconstructions havebeen proposed, relationships are obscure. The typespecies of Ellisonia, E. triassica Müller, was described(as a form-species) from Smithian strata in Nevada butits apparatus has not been reconstructed from the typelocality. Multielement reconstructions from other local-ities by Sweet (1970) and Koike (1990) lack P elementsbut it is probable that small segminate or angulateelements like the Griesbachian species ‘Neospathodus’peculiaris Sweet represent those elements. These re-semble latest Permian Merrillina, from which both El-lisonia and Hadrodontina evolved according to Kozur(2004, p. 54). It is not clear whether such elementsshould be referred to Merrillina or Ellisonia in theearliest Triassic, but homologous elements in youngerellisonid faunas show progressive development of theposterior process and denticulation (Fig. 3), as shown byMerrillina?/ Ellisonia? n. sp. A from the late Griesba-chian of the Arctic; Merrillina?/Ellisonia? n. sp. B(including Neospathodus peculiaris sensu Birkenmajerand Trammer, 1975) from the Dienerian; and the P1element of the recent reconstruction of Ellisonia triassicafrom Smithian strata of the Taho Formation, Japan (Koikeet al., 2004). However, the latest Permian naturalassemblage referred to Ellisonia sp. cf. E. triassica byKoike et al. (2004) appears to have a P1 element similar tothe Smithian example, suggesting a long-ranging con-servative morphology for some ellisonids.

Most records of Ellisonia triassica in the literaturerefer to the ramiform elements and need to be re-evaluated in order to understand the true range of diag-nostic P1 elements. Similar P1 elements occur also inassemblages referred to the Alpine Ellisonia agordinaPerri and Andraghetti and Hadrodontina aequabilisStaesche (reconstructed by Perri, 1991), but the basalconfiguration of these elements differ. The formerspecies in particular has an inverted basal cavity andresembles Sweetocristatus unicus Dagis from the earlySmithian of Siberia; similar elements possibly belong-ing to Sweetocristatus? are also known from the lateSmithian and early Spathian of North America. Multi-element Ellisonia dinodoides (including form speciesMetalonchodina? dinodoides Tatge), as reconstructedby Koike (1994), is a long-ranging association thatis believed to constitute parts of an unrelated stock.Ellisonia-like ramiform elements occur rarely in collec-tions from the Spathian and Anisian in North Americabut their multielement context is not known at present.

Some ellisonid elements referred to Hadrodontinaand Pachycladina may be parts of apparatuses differentfrom their type species, both of which were describedfrom the Werfen Formation in the Southern Alps of

Italy; their multielement apparatuses are now knownfrom the same unit. Hadrodontina aequabilis Staescheappears about the base of the Griesbachian staescheiZone (Perri, 1991; Perri and Farabegoli, 2003), andHadrodontina anceps Staesche appears in the lateDienerian (Perri, 1991). Smithian P1 elements of H.anceps resemble those of contemporaneous Ellisoniaaff. triassica sensu Koike et al. (2004) from the TahoFormation in Japan and also to Pachycladina peculiarisZhang (now assigned to Parapachycladina Zhang).These three taxa appear to constitute a natural groupeven though they are currently assigned to differentgenera. Species of Pachycladina appear in the Dienerianin both the Alps with P. obliquaa Staesche (Perri andAndraghetti, 1987), and in China with P. enomenaZhang.

Parachirognathus ethingtoni Clark and Furnishiustriserratus Clark occur in Smithian strata deposited onthe shelf of ancient western USA, where they form alocal range-zone (Clark et al., 1979). The same faunaoccurs in inner-shelf environments in southern Pri-morye, Russia (Buryi, 1979, 1997), and in China themultielement Parachirognathus gracilis Zhang andYang is broadly contemporaneous. Carr et al. (1984)determined that Parachirognathus and Furnishius had areciprocal relationship whereby the former dominatedthe inner shelf and the latter the outer shelf. Foliella andpossibly Platyvillosus sensu stricto (see above) may bederivatives of Furnishius. Finally, ‘Neospathodus’ n. sp.G from Chaohu is an unusual element that may be anellisonid. It appears that most ellisonids disappeared bythe end of the Smithian.

2.4. The family Sweetognathidae

There is some doubt as to the last occurrence ofsweetognathids, which were important in faunas throughmuch of the Lower and Middle Permian. Very rarespecimens of Iranognathus sosioensisKozur andMostlerwere reported from one locality in the Late Permian ofSicily associated with conodonts, including Hindeoduslatidentatus, which imply a late Changhsingian age(Kozur and Mostler, 1996). However, Mei et al. (2002,p.15) found I. sosioensis only in the lower Lopingian inChina, where it predates the latest Wuchiapingian–earlyChanghsingian Iranognathus tarazi, which they regard asthe last representative of the genus and family.

2.5. The genus Vjalovognathus

Vjalovognathus Kozur is an unusual cool-water co-nodont belonging to a new unnamed family, which


occurs from Artinskian through Lopingian strata in thesouthern palaeolatitudes (Nicoll and Metcalfe, 1990;Mei and Henderson, 2001). The last representative isapparently Vjalovognathus n. sp. B. of Mei andHenderson (2001, tbl. 1), which presumably corre-sponds to Vjalovognathus n. sp. 2 of Wardlaw and Mei(1999) from the lower Chhidru Formation in Pakistan.Hence the genus and family appears to have becomeextinct in the lower Changhsingian.

3. Conodont extinction and radiation, latestPermian to Middle Triassic

A general decline in condontophorids was welladvanced by the Late Permian, with diversity levelshaving been in decline since the Late Devonian heyday.By the Middle Permian, there were representatives ofperhaps five families, and all of them appear to havesurvived the extinction that has been identified at theend of the Guadalupian (e.g. Isozaki et al., 2004). It hasbeen suggested that a subsequent global cooling in theChanghsingian resulted in both the return of cool-watergenera Vjalovognathus and Merrillina into the SaltRange and the extinction of Iranognathus in the lowerChanghsingian (Mei and Henderson, 2001, p. 255).Vjalovognathus appears to have disappeared soon after,and by the latest Permian only Merrillina and ellisonidsremained alongside the more common gondolellids andanchignathodontids.

Fig. 4 shows conodont diversity from the lateChanghsingian through the late Olenekian based ontaxa identified and discussed above. Although addition-

Fig. 4. Numbers of conodont species during nine int

al taxa are likely to be identified in the future, theobserved trends and events are regarded as real. Threeconodont families and perhaps four genera survived upto the PTB where the first representatives of two moregenera appeared. All six genera crossed the PTB, onboth sides of which extinction and origination rates wereat similar levels. A minimum of about 22 species ofNeogondolella, 27 species belonging to the Hindeodus–Isarcicella group, and several ellisonids occur in the sixconodonts zones (zhangi through isarcica) identified byKozur (2005) as straddling the PTB. By the topmostPermian meishanensis–latidentatus Zone, there wereabout 15 Neogondolella species and 13 Hindeodus(mostly) species extant. Of these, respectively nine and10 species, or approaching 70%, crossed the PTB; aboutfive Tethyan and three Boreal gondolellids disappeared.Whereas the anchignathodontid stock continued todiversify in the lower Induan, most of the contempora-neous gondolellid species had already appeared duringthe meishanensis–latidentatus Zone and crossed thePTB. Neogondolella krystyni was the first evolutionaryinnovation within the Induan gondolellids. No majorchange across the boundary has been documentedamongst the poorly known ellisonids. The broader pictureof late Changhsingian through late Greisbachian cono-dont diversity (Fig. 4) shows a comparable situation onboth sides of the PTB, with a decline in gondolellids beingoffset by an increase in anchignathodontids. A majorconodont faunal change occurred in the late Griesbachianwith the disappearance of the anchignathodontids andthe emergence of the first species of Neospathodus,Sweetospathodus, and Borinella? Although there was

ervals of the latest Permian and Early Triassic.


continued decline in the numbers of Neogondolellaspecies, the zone of Bukkenites strigatus in the CanadianArctic contains both old and new species. Alongsidethe long-ranging N. ex gr. carinata, new innovationquickly led to Borinella? and, by the early Dienerian,Scythogondolella? The radiation of other gondolellidsalso began early in the Dienerian with morphotypicdifferentiation in N. dieneri but, as far as is known, themultielement apparatuses of the gondolellids were notstrongly differentiated at the time. Ellisonid diversityappears to have remained fairly constant through theinterval (Fig. 4).

By the late Dienerian, conodont diversity increasedsomewhat with Neospathodus-like derivatives increas-ing at the expense of the more restricted Neogondolella-like elements. The former became the dominant cono-dont in many faunas and continued to radiate alongseveral lines differing in denticulation and basalconfiguration, i.e. the pakistanensis, chaohuensis, chii,and cristagalli groups, early representatives of theMullerinae, and Platyvillosus. Neogondolella becamemore restricted in range but continued to evolve inpelagic environments around Panthalassan atolls andin high northern latitudes. Amongst the ellisonids,Hadrodontina and Pachycladina evolved from Ellisonia.The Dienerian radiation was, however, much moreprofound than these new taxa suggest. Although weknow little of the details, a revolution in multielementapparatuses was underway.

The early to middle Smithian saw an explosive radi-ation in conodont evolution with the appearance of

Fig. 5. Total number of genera (pale grey) and number of known gondolellidearly Anisian.

numerous new species and genera (Figs. 4 and 5).However, an equally or more remarkable aspect of thesenewly emerged conodonts was the morphologicaldiversity in multielement apparatuses: there were atleast 12 within Lower Triassic gondolellids alone, com-pared with perhaps one in the Late Permian (Fig. 5). Inshallow water, radiation amongst the ellisonids alsoincreased (Fig. 4). The early Smithian ammonoid zoneof Euflemingites romunduri in North America, and ofthe broader zone of Hedenstroemia in Russia, was theacme for Triassic conodonts and a diversity peakunrivalled since the middle Palaeozoic.

The late Smithian Tardus Zone marks a dramaticreduction of conodont species and apparatuses. By theend of the stage, all representatives of the Mullerinae,most of the Neospathodus groups (other than theN. waageni line), plus Wapitiodus, Scythogondolella,and possibly Borinella became extinct. The turnoveramongst ellisonids was also pronounced with the disap-pearance of most genera. By Tardus Zone time,conodont faunas in North America are dominated byone or two species characterized by segminiplanate P1elements, and representatives of the Neospathoduswaageni group. Elsewhere, only representatives of theCornudininae, the coniform Aduncodina, and possiblysome long-ranging ellisonids remained. In terms of itsimpact on generic diversity, the late Smithian conodontextinction was the largest of the Triassic (Fig. 4).

A new conodont radiation began early in theSpathian. Neogondolella began to radiate along severallines, including those that led to N. jubata, Columbitella

multielement apparatuses (dark grey) during the latest Permian through


elongata, and their many derivatives. The first Gladi-gondolella and the related Cratognathus appeared inlow palaeolatitudes. Amongst the Neospathodus-likeforms, Novispathodus abruptus is regarded as the rootstock for the short lived Icriospathodus, the moreenduring Triassospathodus, and other lineages leadingto N. brevissimus, N. triangularis, and N. tulongensis.Aduncodina, Neostrachanognathus, and Platyvillosusbecome common in some low paleolatitude faunas.

After the middle Spathian Columbites Zone, cono-dont diversity dropped once again (Fig. 4). Faunas fromthe North American Haugi and Subrobustus zonesgenerally include only a few species and are dominatedby Triassospathodus, Neogondolella ex gr. regalis, andNeogondolella n. sp. H. Tethyan faunas are morediverse and include, in addition to Triassospathodus,the genera Cratognathus andGladigondolella, membersof the Cornudininae, and the last Neostrachanognathus.At the very end of the Spathian, further innovationresulted in the appearance of two new genera, Chiosellaand New Genus A. Most of these late Spathian cono-donts crossed the Olenekian–Anisian boundary, recog-nized by the appearance of Chiosella timorensis(Nogami), but Triassospathodus, representing the lastof the Neospathodus stock, disappeared shortly after.Younger Anisian faunas are dominated by Neogondo-lella, Paragondolella, Gladigondolella, Cratognathus,Nicoraella, and Cornudina. Conodont diversity neveragain achieved Smithian levels.

4. Discussion

The review of Lower Triassic conodonts and theirimmediate forebears reveals a fluctuating history ofdecline, extinction, and radiation. An explanation forthese patterns is sought in the complex interplay ofenvironmental factors that influenced the Late Permianand Early Triassic world. Much has been written aboutthe dramatic extinction at the PTB, unrivalled in itsmagnitude and impact on the biosphere. Similarly,documentation of the fossil record shows that manyanimal groups did not recover from the trauma until theMiddle Triassic. Neither is true of the conodonts, al-though they were not immune to the major environ-mental changes that took place at the time.

Extinction events that impacted other groups at theend of the Guadalupian and again within the uppermostChanghsingian are not clearly recorded as majorchanges in the conodont record. The end-Permianevent has been linked to various phenomena (see Payneet al., 2004 for summary) that may be responsible forthe carbon isotope excursion recorded at the PTB. At

Meishan in China, a δ13Cminimum occurs immediatelybefore the PTB and just after the extinction of 94% ofthe 15 represented fossil groups (Jin et al., 2000). Thisnegative shift, within the meishanensis–latidentatusZone (beds 25–27b), has been linked to transgressingseas and accompanying anoxia (Wignall et al., 1996).Similar δ13C excursions are well documented at thePTB globally, both in deep-basin and shallow-shelfareas of epicontinental seas, and on seamounts withinthe vast Panthalassa Ocean (Musashi et al., 2001). Theanoxia seems to have occurred first in deep-water ba-sins, and later in shallower waters and at more southerlylatitudes (Wignall et al., 1996). Multiple δ13C minimaare recorded from boundary conodont zones in Iraniansections (e.g. Korte et al., 2004), including one in thebasal Triassic parvus Zone that marks a slightly laterdate for the extinction of the warm-water Tethyanconodonts (principally the Neogondolella subcarinatagroup). A further minimum occurs in the succeedingisarcica Zone in Iran, after which cool-water Borealconodont faunas allegedly occupied the vacated Tethyanbiotopes (Kozur, 1998). General anoxic conditionsprevailed through the entire Griesbachian according toTwitchett and Wignall (1996), and further negativeexcursions occurred again in the Smithian and Spathian(Payne et al., 2004; see below).

Kozur (1998, p. 147–8) regarded the entire PTBinterval as a low-diversity zone for conodonts, but thesame could be claimed for the whole of the Middle andUpper Permian, and certainly for most of the Changh-singian. There was no pronounced conodont diversityplunge at the PTB: many Neogondolella species crossedthe boundary, far more than the few species thatdisappeared in Iran and China. The anchignathodontidsreveal a similar story with comparable origination rateson both sides of the boundary. By the parvus Zone andthe beginning of the Triassic, conodont faunas from thenorthern margin of the Indian subcontinent becamedominated by Neogondolella with fewer Hindeodusspecies. In contrast, in South China and in the Werfenfacies of the Alps, the faunas are dominated bydiversifying anchignathodontids, often to the exclusionof Neogondolella. The change in conodont biofaciesand the contrast in biofacies between different sectionsare pronounced, but it should not be confused withextinction. The Neogondolella meishanensis conodontrange-zone straddles the PTB and many associatedspecies ranged through the earliest Triassic. The “mini-mum low-diversity zone” (Kozur, 1998) applies only toMeishan and similar areas from where Neogondolellawas excluded. The totality of conodont faunas remainedstable until the late Griesbachian.

Fig. 6. Lower Triassic stages, absolute ages, and North American ammonoid zones (after Tozer, 1994; Ovtcharova et al., 2006; Lehrmann et al.,2006), sequence stratigraphy and sea levels fluctuations (partly after Embry, 1997), and carbon isotope geochemistry (after Payne et al., 2004). The“Events” column refers to the steps in conodont evolutionary history enumerated in the conclusions.


Changes in the late Griesbachian appear moreprofound than at the PTB. The anchignathodontidsbecame extinct (the first family to do so since the earlyChanghsingian), and many of the PTB Neogondolellaspecies disappeared. These extinctions coincide with thefirst of the intra-Triassic δ13C minimum shown byPayne et al. (2004; Fig. 6), but whether this is cause oreffect is not known. Its impact on conodonts seems tohave been more severe than that which accompaniedthe PTB anomaly. Postulated global warming (Meiand Henderson, 2001) may have impacted cool-waterNeogondolella species, although the Neogondolellacarinata stock continued in higher latitudes (Fig. 1).However, climatic warming is an unlikely reason for theextinction of the anchignathodontids. A late Griesba-chian lowstand at this time (Fig. 6) is not globallyrecognized but may have been a factor.

Following the late Griesbachian extinction, there wassignificant evolutionary innovation as several newconodont lineages appeared (Figs. 1 and 2). Thereafter,both novel P1 elements, and the apparatuses of whichthey formed part, evolved rapidly. The extinctions at thistime are counterbalanced by originations, so the totaldiversity is maintained at a moderate level (Fig. 4). Inspite of a local transgression in the early Dienerian(Embry, 1988), the stage was largely a time of pro-grading terrigenous sediments in North America, as isevident from the distribution of lithofacies belts in thewestern USA (Clark and Carr, 1984). The Dienerian

also saw the return of normal benthic conditions(Twitchett and Wignall, 1996), and a positive δ13Cexcursion to maximum values by the end of the stage(Payne et al., 2004). In the generally shallower, welloxygenated environments, Neospathodus became dom-inant and flourished, perhaps filling the widespreadneckto-planktic niches formerly occupied by Hindeodus.Neogondolella and its derivatives, on the other hand,became more restricted, inhabiting deeper and coolerparts of Panthalassa. This explains the ‘Neogondolellagap’ that has strongly influenced ideas of Triassicconodont phylogeny. By the late Dienerian, many newNeospathodus lineages had appeared and further newgenera are differentiated (Figs. 1, 2 and 5), although thekummeli lineage ended at the late Dienerian sequenceboundary. The Dienerian was a time of profound changeas new niches were exploited and conodont apparatusesdiversified. These may have been an outcome of isolationduring regression or a response to local transgression, but‘normal’ marine conditions encouraged ongoing evolu-tionary innovation that was well advanced by the time theOlenekian dawned.

The major transgression that occurred around thebase of the Olenekian, or Smithian (Fig. 6; Embry, 1988;Egorov and Mørk, 2000), coincides with acceleratedevolution and an explosive radiation amongst conodontsunrivalled since the Devonian (Fig. 4). The evolution ofmultielement conodonts initiated during the late Induanis manifest as many new taxa with many novel


apparatuses spread and diversified throughout themarine realm (Figs. 4 and 5). In the harsh environmentsof the shallow-water Werfen facies, where body fossilsalso became more common at this time (Twitchett andWignall, 1996), ellisonids show innovation equal to thatof the more open-marine gondolellids. This was theacme of Triassic conodonts. This entire interval ofradiation falls within a period of positive carbon isotopevalues (Payne et al., 2004).

The late Smithian saw a dramatic decline in conodontdiversity (Fig. 4) with the extinction of many lineages(Figs. 1–3). It coincides with a major lowstand, whichmarks a 3rd order system tract boundary, and a δ13Cminimum (Fig. 6). Ovtcharova et al. (2006) speculatedon the role of renewed volcanism on the extinctionamongst ammonoids at this time, which may also havebeen a factor.

The early Spathian radiation may be linked to thenormalizing of the marine environment and locally a mid-Spathian transgression (Clark and Carr, 1984; Hirsch,1994). Again, δ13C values show a positive swing at thistime. Both Neospathodus and Neogondolella diversifiedinto many short lived taxa and by the mid-Spathian,diversity had rebounded (Fig. 4). This was also reflectedin the total number of multielement apparatuses present inthe Spathian (Fig. 5).

The late Spathian diversity drop-off (Fig. 4) parallelsa downturn in δ13C values (Payne et al., 2004) and athird major lowstand coincident with a major (2nd order)sequence boundary (Embry, 1997). This time alsomarks amajor turnover in ammonoids, nautiloids, and bivalves(Egorov and Mørk, 2000). For conodont faunas, the earlyAnisian transgression coincidedwith the disappearance ofthe important Neospathodus stock, and the ascendancy ofpelagic Neogondolella. Thereafter, conodont diversitynever achieved Lower Triassic levels again.

The remarkable evolutionary flourish of conodonts inthe post-PTB world is all the more remarkable when oneconsiders the proposed absolute time framework(Fig. 6). Within as little as one million years conodontsunderwent a profound evolutionary radiation equal to orgreater in its impact on the group than the PTB extinc-tion that preceded it.

5. Conclusions

Upper Permian and Lower Triassic conodont diversityfluctuationsmeasured at the species and higher taxonomiclevels (Figs. 4 and 5) show the following features:

1) Gradual decline in families and genera through theChanghsingian to the late Griesbachian. The group

was reduced from five families at the beginning ofthe Changhsingian to three by the PTB, and to twolate in the Griesbachian. During that entire interval,there appears to have been a single multielementapparatus type within the family Gondolellidae.

2) Extinction of warm-water Tethyan endemics and re-placement by Boreal stocks close to the PTB cor-responding to a change in sedimentary regime andresultant conodont biofacies change, events explainedby both widespread anoxia and global cooling accom-panying massive volcanism.

3) Faunal turnover with extinction of anchignathodon-tids and many cool-water Neogondolella species andorigination of new gondolellids in the late Griesba-chian corresponding to a δ13C minimum, localregression, and possible global warming.

4) Radiation in Neospathodus species and diversifica-tion in conodont multielement apparatuses during theDienerian concurrent with a return to normal-marineconditions.

5) Explosive evolutionary radiation in the early–middleSmithian corresponding to a major basal Olenekiantransgression. This was the strongest radiation of theTriassic with the appearance of numerous new spe-cies and at least 12 gondolellid apparatuses.

6) Major extinction of both species and apparatus typesin the late Smithian corresponding to a lowstand andmajor sequence boundary, and coincident with a δ13Cminimum and possibly renewed volcanism. This wasthe biggest of the Triassic, affecting more taxa thanboth the PTB and the final end-Triassic extinctions.

7) Significant radiation early in the Spathian with rapidrecovery in species and appearance of modified ap-paratuses concurrent with a return to normal-marineconditions. After this radiation, the total number ofSpathian gondolellid apparatuses equalled those inthe Smithian.

8) Gradual net decline in diversity in the late Spathianthrough earliest Anisian as the Neospathodus stockwas reduced and finally disappeared and gondolellidapparatuses were reduced to perhaps seven early inthe Anisian, and five shortly thereafter. This cor-responds to a lowstand and sequence boundary closeto the Lower–Middle Triassic boundary followed bya major transgression in the early Anisian; a largepositive carbon isotope excursion starts in the upperSpathian and peaks in the early Anisian.

In spite of the biotic upheaval around the PTB, genericdiversity in conodonts increased steadily from the PTBthrough the Smithian, and then declined through theAnisian (Fig. 5). More dramatic was the increase in


conodont apparatus types: in gondolellids, these grewfrom one in the Late Permian–Griesbachian, to at least 12in the Smithian. Dienerian apparatuses are poorly known

but the interval must have been a time of majorinnovation. The one–two million year interval duringwhich this took place makes it all the more remarkable.


Conodont evolutionary patterns correlate well withsea-level change (Fig. 6). Radiations correspond totransgressive events, as in the early Griesbachian, earlySmithian, and early Spathian, whereas faunal turnoversoccurred around lowstands, as in the late Griesbachian,late Smithian, and late Spathian. However, there was nomajor extinction in the late Dienerian, and the Anisiantransgression did not produce a great radiation. In fact,in contrast to the Middle Triassic recovery of reef-building organisms and other benthic biota, conodontdiversity went into decline.

Conodont extinction and radiation events also partlycoincide with perturbations in the carbon cycle (Fig. 6).Carbon isotope minima around the PTB, late Griesba-chian, late Smithian, and late Spathian correspond toconodont extinctions, and the largest δ13C decline in theSmithian reached a minimum coincident with the largestconodont extinction of the Triassic. However, it is notstraightforward cause and affect. Negative δ13C valuesat the PTB translate into zero impact on anchignatho-dontids, whereas the isotope minimum in the lateGriesbachian coincides with the extinction of the family.On the other hand, positive isotope trends in theDienerian and Spathian equate with major diversifica-tion, and maximum values in the early Smithian markthe heyday of Triassic conodonts.

6. Taxonomic notes

Borinella chowadensis n. sp.Plate I, nos. 12–14, 26Holotype: GSC 120331 from GSC loc. C-303940.

Toad Formation, ridge south of Chowade River,northeastern British Columbia. Probably Dienerian.

Plate I. All P1 elements magnified ×80.

1, 2. Borinella nepalensis (Kozur and Mostler). GSC 120326 from saMikin Formation; Muth, Spiti. “Flemingites Beds”.

3, 8–11, 16–18. Borinella? megacuspa n. sp. GSC 120328 from GSC loc.(Candidus Zone), and GSC 120330 from GSC loc. 51663 (Strigabase), south of Otto Fiord, Ellesmere Island. Late Griesbachian a

4–6. Borinella sweeti (Kozur and Mostler). Holotype OSU 28068. SNammal, West Pakistan. Dienerian.

7, 15, 27. Borinella buurensis Dagis. GSC 120327 from GSC loc. 9954Columbia. Tardus Zone, Smithian.

12–14, 26. Borinella chowadensis n. sp. Holotype GSC 120331, and GSC 1River, northeastern British Columbia. Dienerian.

19–21. Scythogondolella? n. sp. A. GSC 120333 from GSC loc. 5166Ellesmere Island. Candidus Zone, Dienerian.

22, 23. Neogondolella griesbachensis n. sp. Holotype GSC 120334 fromOtto Fiord, Ellesmere Island. Strigatus Zone, Griesbachian.

24, 25. Neogondolella mongeri n. sp. Holotype GSC 120335 from GSCsouthern British Columbia. Dienerian.

Derivation of name: Chowade River, near the typelocality.

Diagnosis: A species of Borinella with a broad plat-form that tapers progressively from the lobate posteriorend to the anterior. High discrete denticles have arelatively triangular shape in profile.

Remarks: The new species has a much broader, moretapered platform and a smaller, less pronounced cuspthan B. megacuspa n. sp. B. nepalensis (Plate I, nos. 1,2) also has a much narrower platform and smaller cuspthan B. chowadensis, and its denticles are higher andnarrower. The platform of B. nepalensis is also mostlydeveloped in the posterior half of the blade and rarelyextends so far to the anterior.

Borinella sweeti (Kozur and Mostler) (Plate I,nos. 4–6) was based on a single figured specimenfrom the Salt Range (Sweet, 1970, Pl. 3, Figs. 23–25, re-illustrated here) that has broken blade denticles thatnevertheless appear to be more closely spaced than allthe previous species. The cusp is comparable to the newspecies but the longer platform has parallel margins forover half its length.

Borinella buurensis (Plate I, nos. 7, 15, 27) is similarin shape to B. sweeti rather than the new species, butunlike other species of Borinella it typically has aweakly developed cusp; an offset posteriormost denticlemay be present in these broader plated species, espe-cially B. buurensis.

Material: ∼30 specimens.Borinella megacuspa n. sp.Plate I, nos. 3, 4, 8–11, 16–18Holotype: GSC 120329 from GSC loc. 51665. Blind

Fiord Formation (165 m above base), south of OttoFiord, Ellesmere Island. Candidus Zone.

mple MO3-12C, Krystyn et al., 2004. Limestone and Shale Member,

51664 (Strigatus Zone), Holotype GSC 120329 from GSC loc. 51665tus Zone). Blind Fiord Formation (105 m, 165 m, and ∼80 m abovend early Dienerian.ample K6-B, Sweet, 1970. Mittiwali Member, Mianwali Formation;

8 (sample 213C). Toad Formation, Toad River, northeastern British

20332 from GSC loc. Chow4. Toad Formation, ridge south of Chowade

5. Blind Fiord Formation (165 m above base), south of Otto Fiord,

GSC loc. 51663. Blind Fiord Formation (∼80 m above base), south of

loc. C-87055. Cache Creek Group, Marble Canyon near Cache Creek,


Derivation of name: Referring to prominent cusp.Diagnosis: A species of Borinella with a relatively

thick but very narrow platform with subparallel margins,a very large and long cusp with a round cross-section,and smaller discrete carinal denticles; the blade is miss-ing in all available specimens, but in the most completeis not exceptionally high. Smaller specimens haveplatform microreticulae but larger specimens appearunornamented.

Remarks: This species, the oldest assigned to thegenus (with question), may have developed from Neo-gondolella griesbachensis n. sp. by thickening andincreased carinal denticle and cusp growth.

Material: 4 specimens.Neogondolella griesbachensis n. sp.Plate I, nos. 22, 23Holotype: GSC 120333 from GSC loc. 51663. Blind

Fiord Formation (∼80 m above base), south of OttoFiord, Ellesmere Island. Strigatus Zone.

Derivation of name: From its occurrence in theGriesbachian of the Canadian Arctic.

Diagnosis: A slender, elongate, and pointed speciesof Neogondolella with subparallel platform margins,low carinal node, the anteriormost three of which form alow fixed blade. The inclined posterior cusp is small andrises from and merges with the posterior platform tip andis connected to a small node to its anterior by a lowridge. The platform bears microreticulae, and on itsunderside there is a small oval posterior pit.

Remarks: This new species is a lanceolate Neogon-dolella that may have developed from one of the nar-rower forms in the earlier Griesbachian, for exampleN. orchardi Mei. It represents a P1 morphology distinctfrom the other gondolellid stocks represented byN. carinata and N. krystyni, as well as Borinella andScythogondolella.

Material: 5 specimens.Neogondolella mongeri n. sp.Plate I, nos. 24, 25Holotype: GSC 120335 from GSC loc.C-203393.

Cache Creek Group, Marble Canyon near Cache Creek,southern British Columbia.

Derivation of name: In tribute to James W.H. Monger,who introduced the author to Cordilleran geology andhelped collect the sample of origination.

Diagnosis: A relatively narrow, elongate Neogondo-lella with mostly subparallel platform margins in latergrowth stages, low subequal carinal nodes, the anterior-most few of which partly fused and form a low fixedblade. The inclined posterior cusp is best developed insmall specimens in which it projects beyond the roundedposterior platform margin; in larger specimens it is less

conspicuous. The platform bears microreticulae, and onits underside there is a small oval posterior pit.

Remarks: This species lies close to N. griesbachensisand an origin in that species seems probable. Alternative-ly, it may have developed from other lanceolate specieslike N. orchardi. It occurs in a large fauna dominated byNeospathodus dieneri and N. ex gr. carinata.

Material: ∼20 specimens.Scythogondolella? n. sp. APlate I, nos. 19–21Description: This species bears a short biconvex

platform developed on the flanks of about four stout,pointed, inclined, triangular denticles that rise graduallytowards the terminal posterior cusp. An incipientplatform flange surrounds the cusp and is similarlynarrow at the preserved anterior end of the element. Anunknown number of denticles extend anteriorly as a freeblade. The underside has a large, shallow, circular basalcavity that extends beyond the platform margins.

Remarks: This unique specimen has a basal cavitylike that seen in Smithian species of Scythogondolella.The basal cavity mimics that of Neospathodus but it isnot as well developed. It is also similar to youngerNeospathodus species that develop platform flanges inlater growth stages, but the denticulation in those is quitedifferent.

Material: 2 specimens.

Acknowledgments

In writing this paper I have benefited from the accessto the conodont collections of several individualsincluding Zhao Laishi (collections from Chaohu,China), L. Krystyn (collections from Spiti, India), andD. Lehrmann (collections from Guandao, China).Samples from Oman were provided by E.T. Tozer, andfrom the USA by H. Bucher, E. Carter, J. Jenks, and W.Weischat. Arctic material was collected with the help ofS. Irwin. Sample processing was largely done by P.Krauss, and microscopy help provided by H. Taylor,both of whom undertook SEM photography. I thank R.Nicoll for his constructive comments on an earlier draftof the manuscript. Zhang Kexin and Wu Ya Sheng arealso thanked for their comments.

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