Bull. Mus. natn. Hist, nat., Paris, 4 e sér., 2,11980,

section A, n° 2 : 507-515.

A new subfamily from Gorong, Seram, Moluccas,

wit h the description of Renaudcypris new genus

(Crustacea, Ostracoda)

by K . G. M C K E N Z I E *

Résumé. — Le genre Renaudcypris nouveau genre est signalé pour la première fois à Gorong. Les caractères de ce genre imposent la création d'une nouvelle sous-famille. L'importance de cette découverte est discutée.

Abstract. — The genus Renaudcypris n. gen. is described for the first time from Gorong. The characters of this genus indicate a placement into a new subfamily. The significance of this record is discussed.

Among the collections made by Th. MONO D dur ing his Rumph ius I I expedit ion to Indonesia, t he interst i t ial faunas were sorted and identified to groups by J . R E N A U D -MORNANT . An oppor tun i ty to examine Ostracodes from these collections arose dur ing a working visit to RENAUD-MORNANT ' S labora tory in November 1978. The most abundant Ostracode was very dist inct ive. In spite of some deter iorat ion in the carapace due to weak acid i ty of the preserving medium, i t soon became obvious t h at a new generic taxon was indicated, even a new subfamily. Subsequent searches of the l i terature have con-firmed th is ini t ial judgement. Therefore, the genus Renaudcypris and subfamily Renaud-cyprinae are here described for the first t ime.

OSTRACODA Latrei l le, 1806

Order PODOCOPA Sars, 1866

Superfamily C Y P R I D A C EA Baird, 1845

Fami ly PARACYPRIDIDA E Sars, 1923

Subfamily RENAUDCYPRINA E n. subfam.

DIAGNOSI S : A subfamily of Paracyprididae characterised by a spinose subquadrate carapace, the valves of which are slightly depressed anterodorsally near the eye region ; and a soft anatomy

* Riverina C.A.E., Wagga Wagga, 2650, Australia.

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which includes antennaJ natatory setae reaching to the ends of the antennal claws ; an elongate maxillule palp ; a stout end claw on the terminal segment of the third thoracic- limb (P III ) ; rather short, curved furcal rami each bearing two posterior bristles as well as an anterior bristle and two powerful pectinated terminal claws. In males, the clasping palps of the right and left first thoracic limbs (P I) are similar, i.e. not dimorphic ; the Zenkers Organ has 5 inner chitinrosettes ; and in the hemipenes, the tubes of the testes form near circles which open dorsally.

DISCUSSION

MCKENZI E ( 1 9 7 9) in a recent review of Paracypr id idae defined i t as compris ing the subfamilies Paracypr id inae, Thalassocypridinae and Cyclocypridinae ; and subsequent ly GHETT I and MCKENZI E ( 1 9 7 9) upgraded Cyclocypridinae to a separate family. The

new subfamily is characterised in part by long na ta to ry setae on the an tennae. Even so, the setae are not as long as in Cyclocyprididae in which they typical ly extend far beyond the antennal claws but are similar in length to those of many Thalassocypr id inae (K E Y -SER, 1 9 7 6 ). In other characters, the soft ana tomy is paracypr id id- l ike. Thus, as wi t h most other paracypr id ids, the maxil lule palp in Renaudcypris is elongate and the respi-ra tory epipod of this l imb has about 2 0 " Strahlen " and 3 downwards-di rected setae ; the P I in males is two-segmented and non-dimorphic ; the P I I is elongate with a long terminal claw ; the P I I I has a strong terminal claw (similar to Paracypris) ; the furca has two posterior bristles (versus one in all Cyclocyprididae) and the hemipenes are not beaked (they are in cyclocypridids).

From thalassocypridines, the new subfamily is readi ly dist inguished by its spinose, subquadra te carapace and the different end claw of the P I I I ; from paracypr id ines i t can be differentiated again by its carapace and by the long antennal na ta to ry setae (which are short in paracypr id ines).

Genus RENAUDCYPRI S n. gen.

ETYMOLOG Y : For J. RENAUD-MORNAN T and generic suffix-cypris. The gender is feminine.

TYP E SPECIES : Renaudcypris gorongae n. sp.

LOCALIT Y : Gorong Island, beach with fresh water rivulet. Coralline sand and algal frag-ments. 1 / 2 5 / 1 9 7 5, coll. Th. MONOD.

DIAGNOSI S : A renaudcypridine genus characterised by its spinose subquadrate carapace and a soft anatomy as noted above.

DISCUSSION

Refer to discussion of the subfamily, and also to conclusions.

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Renaudcypr is gorongae n. sp.

(Fig. 1-23)

ETYMOLOG Y : For Gorong, the collection locality.

DESCRIPTIO N

Carapace of medium size (about 0.55-0.60 mm in males and 0.60-0.65 mm in females) ; subquadra te ; anter ior more broadly rounded t han the posterior ; dorsum relat ively straight t rending obliquely downwards to the rear from its highest part anteromedial ly, slightly depres-sed (concave) in front of this highest p a r t; venter a lmost stra ight, w?akly inflexed medial ly ; surface considerably affected by the preserving medium but apparent ly punc ta te and covered wit h spiky hairs ; colour in lif e unknown ; greatest height anteromsdial and over 55 % of the length. In dorsal view subell ipt ical, anter ior more narrowly rounded t han the pos-terior, greatest b readth medial and less than half the length. Internal ly, lamellae mode-rate ly broad anter ior ly and narrow posteroventra l ly ; tine of concrescence narrow, except medioventral ly ; anter ior and posterior vestibules well developed ; selvage weak ; radial pore canals numerous, unbranched, shorter anter ior ly and posteriorly t han ventral ly ; normal pore canals scat tered, simple, some indicat ing the presence of a narrow r im ; hinge adont to weakly lophodont, the terminal elements being sl ightly expanded ; adductor muscle scars of cypr idacean type, comprising a group of 4 large and 2 much smaller scars, plus 2 elongate mand ibu lar scars and 2 small upper- f rontal scars ; dorsal scars not observed.

Antennules 7-segmented ; length rat ios of the segments 38 : 13 : 11 : 11 : 11 : 7 : 6 ; dorsal /ventral chaeto taxy of the segments 1/2, 1/0 (?), 0 /1, 2 /1, 2 /1, 5/0 ; plus 2 long ter-minal na ta to ry setae and a single shorter distal seta wi t h a sensory t i p ; the dorsal setae of the 4th, 5 th and 6th segments are long and na ta to ry. Antennae 5-segmented ; length ratios of the 3 endopod segments 4 : 2 : 1 ; ventral sensory bristle of the first endopod segment sutured medial ly ; na ta to ry setae 7 in number, one short the other 6 about equal ly long and reaching to the t ips of the terminal claws ; second endopod segment wi th 3 dorso-distal claw and the th i rd endopod segment wi th a single terminal claw ; exopod comprising a single long brist le plus 1 or 2 very small bristles sited proximodorsal ly on the first endo-pod segment. Mandible coxales wi th 6 teeth, plus small anter ior and posterior brist les, the anter iormost too th is s t rong and simple, the second and th i rd tee th are t r icuspate and the remain ing 3 teeth are simple ; the coxal musculature makes i t clear t hat this is a t rans-verse-bit ing s t ruc ture capable of some promotor- remotor m o v e m e n t; endopod 4-segmented, length rat ios of the segments 10 : 9 : 10 : 6.5 ; dorsal /ventral chaeto taxy of the endopod segments 0/3, 2/3, 4/3, plus 3 claw-like terminal bristles ; epipod obscured. Maxillules wi t h palp elongate, two-segmented ; th i rd lobe wi t h 2 smooth tooth- l ike bristles ; epipod wit h about 20 Strahlen plus 3 downward-point ing setae. Maxil lae (P I) in females with an unsegmented endopod bear ing 3 short terminal setae ; epipod with 5-6 Strahlen ; exopod wi t h about 12 st rong food-forwarding bristles ; in males the palps (endopods) are modified into the typical 2-segmented cypr idacean clasping organs and are not d imorphic (i.e. r ight and left palps are similar). Walk ing legs (P II ) 5-segmented ; the first endopod segment finely h i rsute vent ra l ly ; terminal claw long and only sl ightly curved. Cleaning l imbs

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FI G 7 - 1 1, 1 4, 1 6. — Renaudcypris gorongae n. gen., n. sp., female : 7, mandible coxale ; 8, mandible endopod'(epipod obscured) ; 9, maxillul e palp and lobes; 1 0, maxill a ( P I ) ; 11, walking leg (P I I ) , 1 4, cleaning limb (P I I I ) ; 16, furca.

FIG . 1 2, 1 5, 1 7. — Renaudcypris gorongae n. gen., n. sp., male : 1 2, left palp P I ; 13, righ t palp P I ; 1 5, hemipenis; 1 7, Zenkers organ.

. 18-23. — Renaudcypris gorongae n. gen., n. sp. : 18, internal view LV , male X 112 ; 19, detail, ante-rior RV, female, X 450; 20, external view RV, female, X 112 ; 21, external view carapace, female, X 112 ; 22. detail, surface hairs and normal pore canals, female, X 450 ; 23, detail, muscle scars (slightly skewed), X 450.

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(P I I I ) reflexed ; 4-segmented wi t h the th i rd segment sutured medial ly into approx imate ly equal subsegments and each of these subsegments bear ing a dorsodistal hook-l ike process ; the terminal segment wi t h a slender moderate ly long reflexed seta, a st rong but sl ightly shorter terminal claw and a short seta. Chitin supports wi t h simple distal points ; forked proximal ly ; the anter ior branch straight, the posterior branch strongly recurved. Furcal rami curved, short and thick, length : height rat io about 6 : 1 measured at the mid- length ; a rma tu re of 2 s t rong claws, the anter ior claw a l i t t l e longer, plus a short anter ior brist le and 2 posterior brist les, the first of these posterior bristles longer t han the second. Lab rum simple, (?) serrate anteroventra l ly. Cups of the naupl ius eye fused. Rake-shaped organs wi t h 6-7 tee th. In males : Zenkers Organ wi th 5 inner chi t inrosettes ; hemipenes w i t h a pointed basal pa rt and broad anter ior process, the spirals of the testes tubes opening dorsal ly.

Dimensions : Holotype, female : length 0.62 mm, height 0.35 mm, breadth 0.29 mm ; paratype,. male : length 0.57 mm, height 0.32 mm, breadth 0.26 mm.

ENVIRONMENTA L ASSOCIATION S

The sed iment associated wi t h this populat ion of Renaudcypris gorongae was analysed by J. R E N A U D - M O R N A N T in her laboratory at Par is. The small sample comprised about equal pa r ts by vo lume of algae and corall ine sand, and only about 13 g of sand remained for analysis after removal of the algae. The results are given in Figure 24 and are consi-

HOO

microns IOOO 2 0 00

FIG . 2 4. — Cumulative weight percent curve for sediment sample wit h Renaudcypris gorongae n. gen., n. sp,

2, 11

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dered to be representat ive, a l though not accurate for the larger-sized grades because of the small sample. The cumulat ive wei thg percent curve indicates t h at the sample is coarse (median 1 000 u.) relat ively well sorted, non-skewed and wi t h a moderate kurtosis. Bear ing in mind the lack of precision in the coarser grades, the interst ices in a sand of this coarseness might well suffice to accomodate populat ions even of such relat ively large ani-mals as Renaudcypris.

The sample was collected near where a small s t ream ran to sea across the beach and i t can be assumed, therefore, t h at Renaudcypris is able to to lerate f luctuations in sal ini ty.

CONCLUSION S

Several species of Ostracodes, which show relat ionships wi t h Renaudcypris gorongae have been described from the general region. These species are : Pontoparta rara Vavra, 1901, from a swamp pool at Matupi, Bismarck Archipelago ; Dolerocypria taalensis Tressler, 1937, from Taal Lake near Wawa in southern Luzon, the Phi l ippines ; Mungava munda Harding, 1962 ; Pontoparta wolffi Hard ing, 1962 and Paracypria eleotridis Hard ing, 1962, all from the slightly brackish (salinity 4.56 ° / 0 0) Lake Te-Nggano, Rennell Island in the Solo-mon Islands.

Of these species, Pontoparta wolffi clearly belongs in Renaudcypris. HARDING , in establ ishing the species, commented t h at i t " ... may at once be dist inguished from the other species and indeed from other Candoninae by peculiarit ies of the 3rd l imb which are sufficiently str ik ing to suggest t h at a new genus should be erected... " ( H A R D I N G , 1962). In addi t ion to th is character, HARDING' S species has an overall similar organisat ion to R. gorongae part icular ly wi th regard to the carapace shape, antennae, P l i s and furcae ; but there are differences in the respective hemipenes, male P Is and the lengths of furcal bristles which establish the two taxa as dist inct species. These two species of Renaud-cypris span Wallace's Line between the Australasian and Or iental regions.

The other taxa all belong in Thalassocypr id inae. Of the four genera involved, Para-cypria and Pontoparta are probably confined to the Austra lasian Region, no tw i ths tand ing records of Pontoparta from Egypt and Flor ida (HARDING , 1955 ; K E Y S E R , 1976) because these represent misidentif ixations — both authors acknowledge several significant diffe-rences between their species and Pontoparta rara. Paracypria s.s. is known from Cha tham Island, off New Zealand, from Victoria, Austral ia, and from Rennell Island in the Solomon Islands. The nemurous Paracypria species described from eastern Afric a early in the cen-tu ry are now assigned to the cyclocypridid genera Mecynocypria and Allocypria (ROME , 1962).

On the other hand, good Dolerocypria and Mungava species have been recorded also from Florida and i t seems reasonable, tak ing into account the dispersal pa t te rns of cypri-dacean Ostracodes (MCKENZIE , 1971), to assign t hem to a global c i rcumtropical brackish fauna as suggested by K E Y S E R (1976).

Disregarding the globally dispersed species, there appear to be three loci for rad ia t ion of these closely related taxa, namely : the Wal lace line between Indonesia and Austra las ia ; the Central American region, from Flor ida to Brazil ; and the East African Lakes System. In terms of current P late Tectonics theory, each locus represents the outcome of a Neogene tectonic event of considerable biogeographic significance. Thus, rad iat ion in the genera

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Mecynocypria and Allocypria was favoured by movements along the Jordan, Red Sea, East Africa Rif t which led to the formation of the East African Lakes each offering oppor-tuni t ies to many groups for speciation into the newly available niches. Similarly, the a l ternate opening and closing of the Central American corridor between the Nearct ic and Neotropic Regions, which is now correlated wi th tectonic act iv i ty in the Caribbean, has become a classic case in the l i terature of evolut ion, due to the work of SIMPSON (1965). Paradoxical ly, the real isat ion t h at Wallace's Line demarcated two zoogeographical Regions (Australasian and Oriental) which did not impinge one upon the other unt il the Neogene, when the Austra lasian block collided against the Indonesian arc, has dawned only recent ly. This Neogene event, and the consequent faunal mixing, compet i t ion and selection, tr ig-gered the radiat ion and speciat ion in local shallow marine and brackish envi ronments of which Renaudcypris is a typical example. In the str ictest sense, therefore, Renaudcypris gorongae and Renaudcypris wolffi are endemic taxa which have evolved at a site which was react ivated (in an evolut ionary sense) dur ing the Neogene.

Acknowledgements

M l l e M. L E BLAN C carried out Stereoscan micrography of the taxon at the Université de Bor-deaux SEM unit.

Types are stored at the Muséum national d'Histoire naturelle, Paris ; and some paratypes at the Australian Museum, Sydney.

The author was able to visit and work at Dr. RENAUD-MORNANT' S laboratory thanks to the award of a French Government Scholarship for 1978.

BIBLIOGRAPHIC REFERENCES

GHETTI , P. F., and K. G. MCKENZIE , 1979. — Generic Key to Italian Freshwater Ostracoda : a Prospectus. VII ° International Congress on Ostracoda, Beograd, July 1979 : 63-69.

KEYSER , D., 1976. — Zur Kenntnis der brackigen mangrovebewachsenen Weichboden Sudwest-Floridas unter besonderer Berücksichtigung ihrer Ostracodenfauna. Dissertation Univ. Hamburg, 192 p.

HARDING , J. P., 1955. — The Armstrong College Zoological Expedition to Siwa Oasis (Libyan desert) 1935. Crustacea : Branchiopoda and Ostracoda. Proc. Egypt. Acad. Sei., 10 : 58-68.

— 1962. — Mungava munda and four other new species of ostracod crustaceans from fish stomachs. Nat. Hist. Rennell Island, British Solomon Islands, 4 : 51-62.

MCKENZIE , K. G., 1971. — Palaeozoogeography of freshwater Ostracoda. Bull. Cent. Rech., Pau-SNPA, 5 (suppl.) : 207-237.

— 1979. — Tasmanocypris, a new marine ostracode genus : and a review of the family Para-cyprididae (Crustacea ; Ostracoda). Pap. Proc. B. Soc. Tasm., 1 13 : 29-37.

ROME , Dom R., 1962. — Ostracodes. Explor. Hydrobiol. Lac Tanganika (1946-1947J Result, scient., 3 (8) : 1-305.

SIMPSON, G. G., 1965. — History of the fauna of Latin America. In : The Geography of Evolution :. Collected Essays. Philadelphia and New York, Chilton Publishers, 249 p.

Manuscrit depose le 11 septembre 1979.