Viallithyris gen n. . (Terebratulida Brachiopoda, ) from ...
8
ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus 70. Budapest 1978. Viallithyris gen. n. (Terebratulida, Brachiopoda) from the Mediterranean Lower Jurassic by A. VÖRÖS, Budapest Abstract - Viallithyris gen. n. with type-species V. gozzanensis (PARONA) is described from the Lower Jurassic of the Alpine segment of the Mediterranean province. The new genus is assigned to Gibbithyrididae on the basis of its horizontal outer hinge plates and crural bases given off dor- sally. Its sulcate anterior margin and "brachidium support" render its systematic position unclear. With 5 figures and 1 plate. The Mediterranean palaeobiogeographic province can be characterized — among others — by a very diverse and rather indigenous Lower Jurassic brachiopod fauna (AGER 1967, VÖRÖS 1977). The Bakony Mts. of Hungary represent a geographically marginal but faunistically typical part of this province. The Hungarian Geological Institute carried out extensive excavations here in the last decades which resulted in a huge amount of Jurassic fossils collected bed by bed. The author has been entrusted with the study of Pliensbachian brachiopods by DR. J. KONDA, Director of the Geological Institute; this opportunity is gratefully acknowledged. A detailed monograph is planned to describe the whole brachiopod fauna; the aim of the present article is to present one of the new genera which have "ancient" (or recurrent) internal features apparently characteristic to many Mediterranean forms. Order TEREBRATULIDA WAAGEN, 1883 Suborder TEREBRA TULIDINA WAAGEN, 1883 Superfamily Terebratulacea GRAY, 1840 Family Gibbithyrididae MUIR-WOOD, 1965 [nom. correct. KATZ & POPOV 1974 (pro Gibbithyridae DAGIS, 1968, nom. transi, ex Gibbithyridi- nae MUIR-WOOD, 1965)] MUIR-WOOD (1965) founded her subfamily Gibbithyridinae on a few Upper Cretaceous genera. This subfamily was elevated to family rank by DAGIS (1968, p. 26.) without any explanation. KATZ & POPOV (1974a) gave a short diagnosis for the family Gibbithyrididae and this is accepted here: "Crural bases keeled, frequently with processes pendent into the dorsal umbonal cavity. Loop short, formed by simple transformation of echmidium ; wings (of the loop) poorly developed or missing." (I.e., p. 23.) Essentially on the basis of shell structure KATZ & POPOV (1974a, 1974b) placed this family into a newly created superfamily Centronellidoidea which was a member of a completely rearranged higher brachiopod systematics of the above authors. Although the Gibbithyrididae really bear certain ancient features resembling some Palaeozoic terebratulids, yet it seems more reasonable to keep this family within the superfamily Terebratulacea until convincing "connecting links" appear. KATZ & POPOV (1974a) differentiated two subfamilies: Gibbit hyridinae MUIR-WOOD (? Triassic- Recent) and Dallithyridinae KATZ & POPOV (Lower Cretaceous - Recent) while a third was added by TCHORSZHEVSKY (1974) namely the Psebajithyridinae (Callovian - Oxfordian). The latter subfa- mily seems to be not quite distinct: it should rather be included into the Gibbit hyridinae. Subfamily GIBBITHYRIDINAE MUIR-WOOD, 1965 KATZ & POPOV (1974a) redefined this subfamily first of all by extending the stratigraphie range and the number of genera assigned. Viallithyris is only tentatively placed into this group since it has sulcate anterior commissure and "brachidium support"* in contrast to the other genera. These fea- tures perhaps would be important enough to erect a new subfamily but it seems advisable to wait until further representatives become known. * This new term is defined below, in the description of the species Viallithyris gozzanensis (PARONA).
Transcript of Viallithyris gen n. . (Terebratulida Brachiopoda, ) from ...
A Magyar Természettudományi Múzeum évkönyve 70. (Budapest 1978)A N
N A L E S HISTORICO-NATURALES MUSEI N A T I O N A L I S H U N G A R
I C I Tomus 70. Budapest 1978.
Viallithyris gen. n. (Terebratulida, Brachiopoda) from the Mediterranean Lower Jurassic
by A . V Ö R Ö S , Budapest
Abstract - Viallithyris gen. n. wi th type-species V. gozzanensis ( P A R O N A ) is described from the Lower Jurassic of the Alpine segment o f the Mediterranean province. The new genus is assigned to Gibbithyrididae on the basis o f its horizontal outer hinge plates and crural bases given off dor- sally. Its sulcate anterior margin and "brachidium support" render its systematic position unclear. Wi th 5 figures and 1 plate.
The Mediterranean palaeobiogeographic province can be characterized — among others — by a very diverse and rather indigenous Lower Jurassic brachiopod fauna ( A G E R 1967, V Ö R Ö S 1977). The Bakony Mts. o f Hungary represent a geographically marginal but faunistically typical part o f this province. The Hungarian Geological Institute carried out extensive excavations here in the last decades which resulted in a huge amount o f Jurassic fossils collected bed by bed. The author has been entrusted wi th the study o f Pliensbachian brachiopods by D R . J. K O N D A , Director o f the Geological Institute; this opportunity is gratefully acknowledged. A detailed monograph is planned to describe the whole brachiopod fauna; the aim of the present article is to present one of the new genera which have "ancient" (or recurrent) internal features apparently characteristic to many Mediterranean forms.
Order T E R E B R A T U L I D A W A A G E N , 1883 Suborder TEREBRA TULIDINA W A A G E N , 1883
Superfamily Terebratulacea G R A Y , 1840 Family Gibbithyrididae M U I R - W O O D , 1965
[nom. correct. K A T Z & POPOV 1974 (pro Gibbithyridae D A G I S , 1968, nom. transi, ex Gibbithyridi- nae M U I R - W O O D , 1965)]
M U I R - W O O D (1965) founded her subfamily Gibbithyridinae on a few Upper Cretaceous genera. This subfamily was elevated to family rank by D A G I S (1968, p. 26.) without any explanation. K A T Z & POPOV (1974a) gave a short diagnosis for the family Gibbithyrididae and this is accepted here: "Cru ra l bases keeled, frequently wi th processes pendent into the dorsal umbonal cavity. Loop short, formed by simple transformation of echmidium ; wings (of the loop) poorly developed or missing." (I .e . , p. 23.) Essentially on the basis o f shell structure K A T Z & POPOV (1974a, 1974b) placed this family into a newly created superfamily Centronellidoidea which was a member of a completely rearranged higher brachiopod systematics of the above authors. Although the Gibbithyrididae really bear certain ancient features resembling some Palaeozoic terebratulids, yet it seems more reasonable to keep this family wi th in the superfamily Terebratulacea unt i l convincing "connecting l inks" appear.
K A T Z & POPOV (1974a) differentiated two subfamilies: Gibbit hyridinae M U I R - W O O D ( ? Tr iass ic- Recent) and Dallithyridinae K A T Z & POPOV (Lower Cretaceous - Recent) while a th i rd was added by TCHORSZHEVSKY (1974) namely the Psebajithyridinae (Callovian - Oxfordian). The latter subfa mi ly seems to be not quite distinct: it should rather be included into the Gibbit hyridinae.
Subfamily GIBBITHYRIDINAE M U I R - W O O D , 1965
K A T Z & POPOV (1974a) redefined this subfamily first o f all by extending the stratigraphie range and the number of genera assigned. Viallithyris is only tentatively placed into this group since it has sulcate anterior commissure and "brachidium support"* in contrast to the other genera. These fea tures perhaps would be important enough to erect a new subfamily but it seems advisable to wait unt i l further representatives become known.
* This new term is defined below, in the description of the species Viallithyris gozzanensis (PARONA) .
Genus V i a l l i t h y r i s gen. n .
D e r i V a t o n o m i n i s : after the name of Mrs . Prof. G I U L I A SACCHI V I A L L I who was the first to study the internal features of the type species.
T y p e - s p e c i e s : V. gozzanensis (PARONA), by monotypy. D i a g n o s i s : Medium sized terebratulids, subpentagonal in outline, valves equally biconvex.
Anter ior commissure sulcate, shell surface capillate. U m b o slightly incurved, beak ridges blunt, fora men mesothyridid to permesothyridid. Outer hinge plates horizontal, crural bases given off dorsally, loop short. Brachidium support present.
D i s c u s s i o n : Viallithyris has a rather un ique in t e rna l m o r p h o l o g y . A m o n g the Mesozoic genera reviewed i n the "Trea t i se" ( M U I R - W O O D 1 9 6 5 ) o n l y Gibbithyris, Orna- tothyris and Concinnithyris have subhor i zon ta l h inge plates and c r u r a l bases given o f f dorsa l ly bu t they are k n o w n o n l y f r o m the U p p e r Cretaceous and hence cer ta in ly no t d i rec t ly re la ted t o Viallithyris. — Recent ly , some new genera have been erected by T C H O R S Z H E V S K Y
( 1 9 7 4 ) f r o m the M i d d l e and U p p e r Jurassic beds o f the USSR, namely , Psebajithyris, Muir- woodella and Karadagithyris w h i c h show in t e rna l features s imi la r t o Viallithyris, especially i n the ca rd ina l parts . Karadagithyris even has someth ing l i k e c ru ra l plates w h i c h were qual i f ied by T C H O R S Z H E V S K Y as o u t g r o w t h s o f the outer h inge plates. However , Karadagi thyris and Muirwoodella be long t o the long- looped terebratul ids a n d can be excluded f r o m subsequent discussion. Psebajithyris is shor t - looped and appears to be closely a l l ied t o Viallithyris. Cor rec t compar i son between the t w o genera is n o t possible since b o t h are m o n o - typ ic as yet bu t some i m p o r t a n t differences can be recorded. Psebajithyris has a unip l ica te o r b ip l ica te an te r ior commissure and a very ind i s t inc t pedicle co l la r i n contrast to the sulcate commissure a n d the s t rong and large pedicle co l l a r o f Viallithyris; the i r s t ra t igraphie ranges are also different : U p p e r and L o w e r Jurassic, respectively.
D i s t r i b u t i o n : Lower Jurassic o f the Southern and Nor thern Limestone Alps and Bakony Mts . (Hungary).
Fig. 1. Variat ion o f wid th ( W ) against length ( L ) o f 73 specimens o f Viallithyris gozzanensis (PARONA)
Viall ithyris gozzanensis ( P A R O N A )
(Plate I : 1-6, Figs. 1 - 5 ) 1 8 8 0 : Terebratula Gozzanensis n . sp. — PARONA, GOZZANO , p . 196. , p l . L , rig. 8. 1 8 8 0 : Terebratula Sismondai n. sp. — PARONA, I b id . , p . 197. , p l . I . , fig. 9 . 1 8 8 4 : Terebratula Engeli H A A S - H A A S , Südtyro l und Venetien, p. 22 . , p l . I I I . , figs. 3 - 5 . 1 8 8 5 : Terebratula (Pygope (?)) Gozzanensis, PAR.-PARONA , Saltrio e Arzo , p. 2 5 2 . , p l . V . , figs. 1 -2 . 1 8 9 3 : Terebratula Gozzanensis, PAR.-PARONA , Revisione, p . 4 2 . , p l . I L , figs. 1 4 - 1 7 . 1 8 9 8 : Terebratula Gozzanensis PARONA-BÖSE , Östl ich. Nordalpen, p . 165. , p l . X L , figs. 8, 1 0 - 1 2 . 1 9 0 0 : Pygope gozzanensis PARONA-BÖSE & SCHLOSSER, Südtyro l , p. 184. , p l . X V I I . , figs. 5, 9 , 10 . 1 9 6 7 : "Terebratula''' gozzanensis PAR.-SACCHI V I A L L I & CANTALUPPI , N u o v i foss. Gozzano, p. 9 7 . ,
pl . X V . , figs. 1-3. , text-figs. 2 2 - 2 3 .
M a t e r i a l : 194 , partly incomplete specimens. D i m e n s i o n s : The length, wid th and thickness data o f 7 3 measurable specimens are pre
sented in Figs. I . and 2 . D e s c r i p t i o n . External characters: V. gozzanensis is a medium to large sized terebratulid,
subpentagonal to subcircular, rarely oval in outline. Both valves are moderately, nearly equally con vex; the maximum thickness is attained at about the middle of the length. The lateral commissure is sulcate but tends to be rectimarginate in the juvenile specimens. The form of the sulcation varies f rom a wide, flattened, angular deflexion to a simple, low sinus. I n adult stage the valves meet at an obtuse angle; exceptionally, concave surfaces may develop along the lateral commissures. Distinct sinus and fold are not discernible. The surface of the shell shows weak and irregularly spaced growth lines; the well-preserved specimens are finely capillate. — Internal characters (Figs. 3 - 4 ) : Pedicle valve: The delthyrial cavity is circular to subtrigonal in cross-section. The pedicle collar is well devel oped, rather long. The deltidial plates are th in and fused, forming a symphytium. The hinge-teeth are moderately long and laterally expanded: crenulation is not developed. The outline o f a narrow and long muscle scar is clearly visible in the cross-sections. — Brachial valve: The cardinal process
Fig . 2 . Variat ion o f thickness (T) against length ( L ) of 7 3 specimens of Viallithyris gozzanensis (PARONA)
is crenulated, rather prominent and extends anteroventrally into the delthyrial cavity. Outer socket ridges are well developed, inner socket ridges are well demarcated from the outer hinge plates. The latter are rather th in and horizontal ; their inner edges are slightly thickened and sometimes are gently curved ventrally. The crural bases are given off on the dorsal side. The crura are arched i n cross-sec t ion ; at first they are convex but anteriorly become concave toward each other. Crural processes are not well defined. The transverse band is moderately arched. The short loop (about one-fourth o f the length o f the brachial valve) ends in two distinct points.
T h e w h o l e b r a c h i d i u m is " s u p p o r t e d " by a special s t ructure . I n some cases ( F i g . 3) i t begins as t w o s l igh t ly d ive rg ing lamellae ex tending f r o m the c ru ra l bases to the floor o f the b rach ia l valve. The lamellae con t inue — or i n o ther cases ( F i g . 4) appear — between the
Fig. 3. Transverse serial sections o f Viallithyris gozzanensis ( P A R O N A ) . Carixian (Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . , Hungary. The brachidium persisted to 6.6 m m from the posterior
end o f the shell. Original length o f specimen about 20 mm, X2.5
c ru ra a n d the valve f l o o r . Here , they f o l l o w the outer r i m o f the dorsa l adduc to r muscle impressions. B e y o n d the field o f the muscle scars they become free o f the valve a n d un i t e dorsa l ly bu t r e m a i n at tached to the l o o p . T h e w h o l e s t ructure ends i n a smal l , sometimes
F ig . 4. Transverse serial sections o f Viallithyris gozzanensis ( P A R O N A ) . Carixian (Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . , Hungary. The brachidium persisted to 9.6 m m f rom the posterior
end o f the shell. Original length o f specimen 27.8 m m . Hung. Geol. Inst. , J. 9178. X2.5
5 Természet tudományi Múzeum Évkönyve 1978.
crenulated, tongue w h i c h fits w e l l under the transverse band o f the l o o p . I t is i m p o r t a n t to note tha t this s t ructure is on ly loosely attached b o t h t o the b r a c h i d i u m and to the b rach ia l va lve ; fu r the rmore , i t shows a ra ther i r regular , sometimes asymmet r ica l development . Nevertheless, i t is a constant and characterist ic feature i n the specimens o f V. gozzanensis as can be observed i n the figures 2 2 and 2 3 by S A C C H I V I A L L I & C A N T A L U P P I ( 1 9 6 7 ) as w e l l .
The new t e r m " b r a c h i d i u m s u p p o r t " is suggested here for this s t ructure since i t is n o t h o m o logous w i t h the s imi l a r skeletal elements o f some other art iculates (e. g. the "ou t e r p la tes" o f the Gypidulidae; the " c r u r a l p la tes" o f the Centronellidae a n d some Dielasmatidae, etc.) .
T h e dorsal adduc to r muscle scars are n a r r o w , short and subparal le l as seen o n the surface o f in te rna l m o u l d s ( F i g . 5 ) .
R e m a r k s : Parona ( 1 8 8 0 ) described " 7 " . Gozzanensis" and " 7 \ Sismondai" as d is t inc t species b u t later he ( P A R O N A 1 8 8 5 ) considered the la t ter o n l y as a var ian t o f gozza nensis. T. engeli H A A S has been inc luded i n t o the s y n o n y m y by SCHLOSSER ( B Ö S E & SCHLOSSER 1 9 0 0 ) and this seems reasonable o n the basis o f the figures given by H A A S ( 1 8 8 4 ) . Recently, S A C C H I V I A L L I & C A N T A L U P P I ( 1 9 6 7 ) gave good i l l u s t r a t i o n o f this species i n c l u d i n g t w o series o f transverse sections bu t left open the ques t ion o f generic assignment. T h e an te r ior parts o f the b r a c h i d i u m suppor t are s l ight ly different f r o m those figured i n the present paper ; this p r o b a b l y reflects v a r a t i o n d u r i n g on togeny since the specimens o f S A C C H I V I A L L I & C A N T A L U P P I are m u c h larger.
V, gozzanensis has some external s im i l a r i t y to Rhapidothyris arciferens T U L U W E I T , 1 9 6 5 , and especially t o Rhapidothyrisl reversa ( A G E R , 1 9 5 6 ) , however , the i r in te rna l characters are very different f r o m those o f V. gozzanensis i n accordance w i t h the different generic pos i t i on . T h e b r a c h i d i u m suppor t appears in several t e rebra tu l id species in the Med i t e r r anean Jurassic b u t the i r other in te rna l and external characters make t hem easily separable even at generic level .
D i s t r i b u t i o n : V. gozzanensis has a character is t ica l ly A l p i n e (Med i t e r r anean) d i s t r i b u t i o n . I t has been described first f r o m the Pl iensbachian o f Gozzano (Piemonte) and later f r o m several o ther locali t ies o f the Southern A l p s and the N o r t h e r n Limestone A l p s , f r o m the same stage. — T h e H u n g a r i a n specimens came f r o m the no r the rn par t o f the B a k o n y M t s . L o c a l i t i e s : Ker icser ( Ibex , D a v o e i and Stokesi Zones) ; K á v á s t e t (Davoe i Z o n e ) ; F e n y v e s k ú t ( p r o b a b l y Marga r i t a tus Z o n e ) ; E p l é n y , manganese-ore mine ( p r o b a b l y M a r g a r i ta tus Z o n e ) .
Fig. 5. Two specimens of Viallithyris gozzanensis ( P A R O N A ) showing the narrow, short and subparallel dorsal adductor muscle scars. Carixian (Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . ,
Hungary. x 2 . Hung. Geol. Inst., J. 9 1 7 9 and J. 9 1 8 0
References
A G E R , D . V . (1956): Some new Liassic terebratuloids. — Proc. Geol. Assoc., 67 (1-2) : 1-14. A G E R , D . V . (1967): Some Mesozoic brachiopods in the Tethys region. — Syst. Assoc. Publ., 7:135-
151. BÖSE, E. (1898): Die mitteliassische Brachiopodenfauna der östlichen Nordalpen. Nebst einem A n
hange über die Fauna des unteren Dogger in bayerischen Innthale. — Palaeontographica, 44:145-236.
BÖSE, E. & SCHLOSSER, M . (1900): Übe r die mitteliassische Brachiopodenfauna von Südtyro l . — Palaeontographica, 46: 175-212.
( D A G I S , A . S.) / J a r u c , A . C . (1968): KDpcKae H paHHeivienoBbie ö p a x M o n o / j b i ceßepa C n ö a p n . — HayKa, MocKBa: 1-167.
H A A S , H . (1884): Beiträge zur Kenntniss der liassischen Brachiopodenfauna von Südtyro l und Ve- netien. — Kie l , p. I - X I V + 1-34.
( K A T Z , Y U . I . & POPOV, A . M . ) K a u , KO. M . & nonoB, A . M . (1974a): HoBbie TaKCOHbi MC303OHCKHX H KaHH030íícKHx neTJieonopHbix 6paxnonofl. — BecmnuK XapbKoe. yn-ma, Feo.i., 108. (5): 22-33.
( K A T Z , Y U . I . & POPOV, A . M . ) K a u , K D . M . & ü o n o B , A . M . (19746): HoBbie aaHHbie o crpyicrype paKOBHH neTJieonopHbix ôpaxHonoa . — Tarn >Ke: 33-42.
M U I R - W O O D , H . M . (1965): Mesozoic and Cenozoic Terebratulidina. — I n : M O O R E , R. C. (Ed.) : Treatise on invertebrate paleontology. (H) Brachiopoda., Kansas, p. 762-816.
PARONA, C. F. (1880): 11 calcare liassico di Gozzano e i suoi fossili. — Atti. R. Accad. Lincei, Mem. Cl. Sei. Fis. Mat. Nat., 8: 187-216.
P A R O N A , C. F. (1885): I brachiopodi liassici di Saltrio e Arzo nelle Prealpi Lombarde. — Mem. R. 1st. Lomb. Sei. Lett., Cl. Sei. Mat. Nat. (3) 15: 227-262.
PARONA, C. F. (1893): Revisione della fauna liassica di Gozzano in Piemonte. — Mem. R. Accad. Sei. Torino (2) 46: 1-62.
S A C C H I V I A L L I , G . & C A N T A L U P P I , G . (1967): I nuovi fossili d i Gozzano (Prealpi Piemontesi). — Mem; Soc. Ital. Sei. Nat., 16(2): 63-127.
(TCHORSZHEVSKY, E. S.) TxopKeBCKHH, 3 . C. (1974): HoBbie aamibie o BHyTpeHHeM crpoetniK paico- B H H H CHCTeMaTHKe KopcKHX TepeöpaTyauaHbix ö p a x a o n o a H3 HaaceMeîicTB Terebratuloidea Gray, 1840n Loboidothyrididoidea M a k r i d i n , 1964. — BecmnuK XapbKoa. yu-ma, Feo.i., 108 (5): 42-58.
T U L U W E I T , K . (1965): Die Terebratulidae und Zeilleriidae (Brachiopoda) des mittleren Lias N o r d westdeutschlands. — N. Jb. Geol. Pal., Abh., 122 (1): 50-126.
V Ö R Ö S A . (1977): Provinciality of the Mediterranean Lower Jurassic brachiopod fauna: causes and plate-tectonic implications. — Palaeogeogr., Palaeoclimatol., Palaeoecol., 21 (1): 1-16.
Author's address: D R . A T T I L A VÖRÖS Geological and Palaeontological Department Hungarian Natural History Museum H-1370 Budapest pf. 330, M ú z í u m körú t 14-16. Hungary
Plate I .
1-3. Dorsal , anterior and lateral views o f Viallithyris gozzanensis ( P A R O N A ) . Carixian (probably Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . , Hungary. X 2 . Hung. Geol. Inst., J . 9182 4-6. Dorsal , anterior and lateral views o f the same species. Carixian (Ibex Zone); locality as above.
X 2. Hung. Geol. Inst., J. 9181
Viallithyris gen. n. (Terebratulida, Brachiopoda) from the Mediterranean Lower Jurassic
by A . V Ö R Ö S , Budapest
Abstract - Viallithyris gen. n. wi th type-species V. gozzanensis ( P A R O N A ) is described from the Lower Jurassic of the Alpine segment o f the Mediterranean province. The new genus is assigned to Gibbithyrididae on the basis o f its horizontal outer hinge plates and crural bases given off dor- sally. Its sulcate anterior margin and "brachidium support" render its systematic position unclear. Wi th 5 figures and 1 plate.
The Mediterranean palaeobiogeographic province can be characterized — among others — by a very diverse and rather indigenous Lower Jurassic brachiopod fauna ( A G E R 1967, V Ö R Ö S 1977). The Bakony Mts. o f Hungary represent a geographically marginal but faunistically typical part o f this province. The Hungarian Geological Institute carried out extensive excavations here in the last decades which resulted in a huge amount o f Jurassic fossils collected bed by bed. The author has been entrusted wi th the study o f Pliensbachian brachiopods by D R . J. K O N D A , Director o f the Geological Institute; this opportunity is gratefully acknowledged. A detailed monograph is planned to describe the whole brachiopod fauna; the aim of the present article is to present one of the new genera which have "ancient" (or recurrent) internal features apparently characteristic to many Mediterranean forms.
Order T E R E B R A T U L I D A W A A G E N , 1883 Suborder TEREBRA TULIDINA W A A G E N , 1883
Superfamily Terebratulacea G R A Y , 1840 Family Gibbithyrididae M U I R - W O O D , 1965
[nom. correct. K A T Z & POPOV 1974 (pro Gibbithyridae D A G I S , 1968, nom. transi, ex Gibbithyridi- nae M U I R - W O O D , 1965)]
M U I R - W O O D (1965) founded her subfamily Gibbithyridinae on a few Upper Cretaceous genera. This subfamily was elevated to family rank by D A G I S (1968, p. 26.) without any explanation. K A T Z & POPOV (1974a) gave a short diagnosis for the family Gibbithyrididae and this is accepted here: "Cru ra l bases keeled, frequently wi th processes pendent into the dorsal umbonal cavity. Loop short, formed by simple transformation of echmidium ; wings (of the loop) poorly developed or missing." (I .e . , p. 23.) Essentially on the basis o f shell structure K A T Z & POPOV (1974a, 1974b) placed this family into a newly created superfamily Centronellidoidea which was a member of a completely rearranged higher brachiopod systematics of the above authors. Although the Gibbithyrididae really bear certain ancient features resembling some Palaeozoic terebratulids, yet it seems more reasonable to keep this family wi th in the superfamily Terebratulacea unt i l convincing "connecting l inks" appear.
K A T Z & POPOV (1974a) differentiated two subfamilies: Gibbit hyridinae M U I R - W O O D ( ? Tr iass ic- Recent) and Dallithyridinae K A T Z & POPOV (Lower Cretaceous - Recent) while a th i rd was added by TCHORSZHEVSKY (1974) namely the Psebajithyridinae (Callovian - Oxfordian). The latter subfa mi ly seems to be not quite distinct: it should rather be included into the Gibbit hyridinae.
Subfamily GIBBITHYRIDINAE M U I R - W O O D , 1965
K A T Z & POPOV (1974a) redefined this subfamily first o f all by extending the stratigraphie range and the number of genera assigned. Viallithyris is only tentatively placed into this group since it has sulcate anterior commissure and "brachidium support"* in contrast to the other genera. These fea tures perhaps would be important enough to erect a new subfamily but it seems advisable to wait unt i l further representatives become known.
* This new term is defined below, in the description of the species Viallithyris gozzanensis (PARONA) .
Genus V i a l l i t h y r i s gen. n .
D e r i V a t o n o m i n i s : after the name of Mrs . Prof. G I U L I A SACCHI V I A L L I who was the first to study the internal features of the type species.
T y p e - s p e c i e s : V. gozzanensis (PARONA), by monotypy. D i a g n o s i s : Medium sized terebratulids, subpentagonal in outline, valves equally biconvex.
Anter ior commissure sulcate, shell surface capillate. U m b o slightly incurved, beak ridges blunt, fora men mesothyridid to permesothyridid. Outer hinge plates horizontal, crural bases given off dorsally, loop short. Brachidium support present.
D i s c u s s i o n : Viallithyris has a rather un ique in t e rna l m o r p h o l o g y . A m o n g the Mesozoic genera reviewed i n the "Trea t i se" ( M U I R - W O O D 1 9 6 5 ) o n l y Gibbithyris, Orna- tothyris and Concinnithyris have subhor i zon ta l h inge plates and c r u r a l bases given o f f dorsa l ly bu t they are k n o w n o n l y f r o m the U p p e r Cretaceous and hence cer ta in ly no t d i rec t ly re la ted t o Viallithyris. — Recent ly , some new genera have been erected by T C H O R S Z H E V S K Y
( 1 9 7 4 ) f r o m the M i d d l e and U p p e r Jurassic beds o f the USSR, namely , Psebajithyris, Muir- woodella and Karadagithyris w h i c h show in t e rna l features s imi la r t o Viallithyris, especially i n the ca rd ina l parts . Karadagithyris even has someth ing l i k e c ru ra l plates w h i c h were qual i f ied by T C H O R S Z H E V S K Y as o u t g r o w t h s o f the outer h inge plates. However , Karadagi thyris and Muirwoodella be long t o the long- looped terebratul ids a n d can be excluded f r o m subsequent discussion. Psebajithyris is shor t - looped and appears to be closely a l l ied t o Viallithyris. Cor rec t compar i son between the t w o genera is n o t possible since b o t h are m o n o - typ ic as yet bu t some i m p o r t a n t differences can be recorded. Psebajithyris has a unip l ica te o r b ip l ica te an te r ior commissure and a very ind i s t inc t pedicle co l la r i n contrast to the sulcate commissure a n d the s t rong and large pedicle co l l a r o f Viallithyris; the i r s t ra t igraphie ranges are also different : U p p e r and L o w e r Jurassic, respectively.
D i s t r i b u t i o n : Lower Jurassic o f the Southern and Nor thern Limestone Alps and Bakony Mts . (Hungary).
Fig. 1. Variat ion o f wid th ( W ) against length ( L ) o f 73 specimens o f Viallithyris gozzanensis (PARONA)
Viall ithyris gozzanensis ( P A R O N A )
(Plate I : 1-6, Figs. 1 - 5 ) 1 8 8 0 : Terebratula Gozzanensis n . sp. — PARONA, GOZZANO , p . 196. , p l . L , rig. 8. 1 8 8 0 : Terebratula Sismondai n. sp. — PARONA, I b id . , p . 197. , p l . I . , fig. 9 . 1 8 8 4 : Terebratula Engeli H A A S - H A A S , Südtyro l und Venetien, p. 22 . , p l . I I I . , figs. 3 - 5 . 1 8 8 5 : Terebratula (Pygope (?)) Gozzanensis, PAR.-PARONA , Saltrio e Arzo , p. 2 5 2 . , p l . V . , figs. 1 -2 . 1 8 9 3 : Terebratula Gozzanensis, PAR.-PARONA , Revisione, p . 4 2 . , p l . I L , figs. 1 4 - 1 7 . 1 8 9 8 : Terebratula Gozzanensis PARONA-BÖSE , Östl ich. Nordalpen, p . 165. , p l . X L , figs. 8, 1 0 - 1 2 . 1 9 0 0 : Pygope gozzanensis PARONA-BÖSE & SCHLOSSER, Südtyro l , p. 184. , p l . X V I I . , figs. 5, 9 , 10 . 1 9 6 7 : "Terebratula''' gozzanensis PAR.-SACCHI V I A L L I & CANTALUPPI , N u o v i foss. Gozzano, p. 9 7 . ,
pl . X V . , figs. 1-3. , text-figs. 2 2 - 2 3 .
M a t e r i a l : 194 , partly incomplete specimens. D i m e n s i o n s : The length, wid th and thickness data o f 7 3 measurable specimens are pre
sented in Figs. I . and 2 . D e s c r i p t i o n . External characters: V. gozzanensis is a medium to large sized terebratulid,
subpentagonal to subcircular, rarely oval in outline. Both valves are moderately, nearly equally con vex; the maximum thickness is attained at about the middle of the length. The lateral commissure is sulcate but tends to be rectimarginate in the juvenile specimens. The form of the sulcation varies f rom a wide, flattened, angular deflexion to a simple, low sinus. I n adult stage the valves meet at an obtuse angle; exceptionally, concave surfaces may develop along the lateral commissures. Distinct sinus and fold are not discernible. The surface of the shell shows weak and irregularly spaced growth lines; the well-preserved specimens are finely capillate. — Internal characters (Figs. 3 - 4 ) : Pedicle valve: The delthyrial cavity is circular to subtrigonal in cross-section. The pedicle collar is well devel oped, rather long. The deltidial plates are th in and fused, forming a symphytium. The hinge-teeth are moderately long and laterally expanded: crenulation is not developed. The outline o f a narrow and long muscle scar is clearly visible in the cross-sections. — Brachial valve: The cardinal process
Fig . 2 . Variat ion o f thickness (T) against length ( L ) of 7 3 specimens of Viallithyris gozzanensis (PARONA)
is crenulated, rather prominent and extends anteroventrally into the delthyrial cavity. Outer socket ridges are well developed, inner socket ridges are well demarcated from the outer hinge plates. The latter are rather th in and horizontal ; their inner edges are slightly thickened and sometimes are gently curved ventrally. The crural bases are given off on the dorsal side. The crura are arched i n cross-sec t ion ; at first they are convex but anteriorly become concave toward each other. Crural processes are not well defined. The transverse band is moderately arched. The short loop (about one-fourth o f the length o f the brachial valve) ends in two distinct points.
T h e w h o l e b r a c h i d i u m is " s u p p o r t e d " by a special s t ructure . I n some cases ( F i g . 3) i t begins as t w o s l igh t ly d ive rg ing lamellae ex tending f r o m the c ru ra l bases to the floor o f the b rach ia l valve. The lamellae con t inue — or i n o ther cases ( F i g . 4) appear — between the
Fig. 3. Transverse serial sections o f Viallithyris gozzanensis ( P A R O N A ) . Carixian (Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . , Hungary. The brachidium persisted to 6.6 m m from the posterior
end o f the shell. Original length o f specimen about 20 mm, X2.5
c ru ra a n d the valve f l o o r . Here , they f o l l o w the outer r i m o f the dorsa l adduc to r muscle impressions. B e y o n d the field o f the muscle scars they become free o f the valve a n d un i t e dorsa l ly bu t r e m a i n at tached to the l o o p . T h e w h o l e s t ructure ends i n a smal l , sometimes
F ig . 4. Transverse serial sections o f Viallithyris gozzanensis ( P A R O N A ) . Carixian (Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . , Hungary. The brachidium persisted to 9.6 m m f rom the posterior
end o f the shell. Original length o f specimen 27.8 m m . Hung. Geol. Inst. , J. 9178. X2.5
5 Természet tudományi Múzeum Évkönyve 1978.
crenulated, tongue w h i c h fits w e l l under the transverse band o f the l o o p . I t is i m p o r t a n t to note tha t this s t ructure is on ly loosely attached b o t h t o the b r a c h i d i u m and to the b rach ia l va lve ; fu r the rmore , i t shows a ra ther i r regular , sometimes asymmet r ica l development . Nevertheless, i t is a constant and characterist ic feature i n the specimens o f V. gozzanensis as can be observed i n the figures 2 2 and 2 3 by S A C C H I V I A L L I & C A N T A L U P P I ( 1 9 6 7 ) as w e l l .
The new t e r m " b r a c h i d i u m s u p p o r t " is suggested here for this s t ructure since i t is n o t h o m o logous w i t h the s imi l a r skeletal elements o f some other art iculates (e. g. the "ou t e r p la tes" o f the Gypidulidae; the " c r u r a l p la tes" o f the Centronellidae a n d some Dielasmatidae, etc.) .
T h e dorsal adduc to r muscle scars are n a r r o w , short and subparal le l as seen o n the surface o f in te rna l m o u l d s ( F i g . 5 ) .
R e m a r k s : Parona ( 1 8 8 0 ) described " 7 " . Gozzanensis" and " 7 \ Sismondai" as d is t inc t species b u t later he ( P A R O N A 1 8 8 5 ) considered the la t ter o n l y as a var ian t o f gozza nensis. T. engeli H A A S has been inc luded i n t o the s y n o n y m y by SCHLOSSER ( B Ö S E & SCHLOSSER 1 9 0 0 ) and this seems reasonable o n the basis o f the figures given by H A A S ( 1 8 8 4 ) . Recently, S A C C H I V I A L L I & C A N T A L U P P I ( 1 9 6 7 ) gave good i l l u s t r a t i o n o f this species i n c l u d i n g t w o series o f transverse sections bu t left open the ques t ion o f generic assignment. T h e an te r ior parts o f the b r a c h i d i u m suppor t are s l ight ly different f r o m those figured i n the present paper ; this p r o b a b l y reflects v a r a t i o n d u r i n g on togeny since the specimens o f S A C C H I V I A L L I & C A N T A L U P P I are m u c h larger.
V, gozzanensis has some external s im i l a r i t y to Rhapidothyris arciferens T U L U W E I T , 1 9 6 5 , and especially t o Rhapidothyrisl reversa ( A G E R , 1 9 5 6 ) , however , the i r in te rna l characters are very different f r o m those o f V. gozzanensis i n accordance w i t h the different generic pos i t i on . T h e b r a c h i d i u m suppor t appears in several t e rebra tu l id species in the Med i t e r r anean Jurassic b u t the i r other in te rna l and external characters make t hem easily separable even at generic level .
D i s t r i b u t i o n : V. gozzanensis has a character is t ica l ly A l p i n e (Med i t e r r anean) d i s t r i b u t i o n . I t has been described first f r o m the Pl iensbachian o f Gozzano (Piemonte) and later f r o m several o ther locali t ies o f the Southern A l p s and the N o r t h e r n Limestone A l p s , f r o m the same stage. — T h e H u n g a r i a n specimens came f r o m the no r the rn par t o f the B a k o n y M t s . L o c a l i t i e s : Ker icser ( Ibex , D a v o e i and Stokesi Zones) ; K á v á s t e t (Davoe i Z o n e ) ; F e n y v e s k ú t ( p r o b a b l y Marga r i t a tus Z o n e ) ; E p l é n y , manganese-ore mine ( p r o b a b l y M a r g a r i ta tus Z o n e ) .
Fig. 5. Two specimens of Viallithyris gozzanensis ( P A R O N A ) showing the narrow, short and subparallel dorsal adductor muscle scars. Carixian (Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . ,
Hungary. x 2 . Hung. Geol. Inst., J. 9 1 7 9 and J. 9 1 8 0
References
A G E R , D . V . (1956): Some new Liassic terebratuloids. — Proc. Geol. Assoc., 67 (1-2) : 1-14. A G E R , D . V . (1967): Some Mesozoic brachiopods in the Tethys region. — Syst. Assoc. Publ., 7:135-
151. BÖSE, E. (1898): Die mitteliassische Brachiopodenfauna der östlichen Nordalpen. Nebst einem A n
hange über die Fauna des unteren Dogger in bayerischen Innthale. — Palaeontographica, 44:145-236.
BÖSE, E. & SCHLOSSER, M . (1900): Übe r die mitteliassische Brachiopodenfauna von Südtyro l . — Palaeontographica, 46: 175-212.
( D A G I S , A . S.) / J a r u c , A . C . (1968): KDpcKae H paHHeivienoBbie ö p a x M o n o / j b i ceßepa C n ö a p n . — HayKa, MocKBa: 1-167.
H A A S , H . (1884): Beiträge zur Kenntniss der liassischen Brachiopodenfauna von Südtyro l und Ve- netien. — Kie l , p. I - X I V + 1-34.
( K A T Z , Y U . I . & POPOV, A . M . ) K a u , KO. M . & nonoB, A . M . (1974a): HoBbie TaKCOHbi MC303OHCKHX H KaHH030íícKHx neTJieonopHbix 6paxnonofl. — BecmnuK XapbKoe. yn-ma, Feo.i., 108. (5): 22-33.
( K A T Z , Y U . I . & POPOV, A . M . ) K a u , K D . M . & ü o n o B , A . M . (19746): HoBbie aaHHbie o crpyicrype paKOBHH neTJieonopHbix ôpaxHonoa . — Tarn >Ke: 33-42.
M U I R - W O O D , H . M . (1965): Mesozoic and Cenozoic Terebratulidina. — I n : M O O R E , R. C. (Ed.) : Treatise on invertebrate paleontology. (H) Brachiopoda., Kansas, p. 762-816.
PARONA, C. F. (1880): 11 calcare liassico di Gozzano e i suoi fossili. — Atti. R. Accad. Lincei, Mem. Cl. Sei. Fis. Mat. Nat., 8: 187-216.
P A R O N A , C. F. (1885): I brachiopodi liassici di Saltrio e Arzo nelle Prealpi Lombarde. — Mem. R. 1st. Lomb. Sei. Lett., Cl. Sei. Mat. Nat. (3) 15: 227-262.
PARONA, C. F. (1893): Revisione della fauna liassica di Gozzano in Piemonte. — Mem. R. Accad. Sei. Torino (2) 46: 1-62.
S A C C H I V I A L L I , G . & C A N T A L U P P I , G . (1967): I nuovi fossili d i Gozzano (Prealpi Piemontesi). — Mem; Soc. Ital. Sei. Nat., 16(2): 63-127.
(TCHORSZHEVSKY, E. S.) TxopKeBCKHH, 3 . C. (1974): HoBbie aamibie o BHyTpeHHeM crpoetniK paico- B H H H CHCTeMaTHKe KopcKHX TepeöpaTyauaHbix ö p a x a o n o a H3 HaaceMeîicTB Terebratuloidea Gray, 1840n Loboidothyrididoidea M a k r i d i n , 1964. — BecmnuK XapbKoa. yu-ma, Feo.i., 108 (5): 42-58.
T U L U W E I T , K . (1965): Die Terebratulidae und Zeilleriidae (Brachiopoda) des mittleren Lias N o r d westdeutschlands. — N. Jb. Geol. Pal., Abh., 122 (1): 50-126.
V Ö R Ö S A . (1977): Provinciality of the Mediterranean Lower Jurassic brachiopod fauna: causes and plate-tectonic implications. — Palaeogeogr., Palaeoclimatol., Palaeoecol., 21 (1): 1-16.
Author's address: D R . A T T I L A VÖRÖS Geological and Palaeontological Department Hungarian Natural History Museum H-1370 Budapest pf. 330, M ú z í u m körú t 14-16. Hungary
Plate I .
1-3. Dorsal , anterior and lateral views o f Viallithyris gozzanensis ( P A R O N A ) . Carixian (probably Ibex Zone); Kericser, near village L ó k ú t , Bakony Mts . , Hungary. X 2 . Hung. Geol. Inst., J . 9182 4-6. Dorsal , anterior and lateral views o f the same species. Carixian (Ibex Zone); locality as above.
X 2. Hung. Geol. Inst., J. 9181
