Eucytherura multituberculata, Michael, 1995

Ayress, M. A., Whatley, R., Downing, S. E. & Millson, K. J., 1995, Cainozoic and from Recent Deep Sea Cytherurid Ostracoda the South Western Pacific and Eastern Indian Oceans, Part Cytherurinae, Records of the Australian Museum 47 (2), pp. 203-223 : 213

Eucytherura multituberculata n.sp.

Fig. 5 A-E

? Tuberculocythere sp. Cronin, 1983: pI. VI, fig. A. " Eucytherura sp." Davies, 1981 *: 147.

" Eucytherura sp. 2" Porter, 1984 *: 155, pI. 9, fig. 11.­ Whatley & Coles, 1987: pI. 3, fig. 18.- Millson, 1987 *: 287; pI. 15, figs 21-23.

" Eucytherura multituberculata" Downing, 1985 *: 442; pI. 29, figs 1,2.- Ayress, 1988 *: 594; pI. 20, figs 18 -21.

Etymology. Latin. Referring to the numerous tubercules which ornament this species.

Type material and dimensions. Holotype, OS 14071, adult left valve, length 0.30 mm, height 0.18 mm. Paratypes: OS 14072, adult right valve, length 0.30 mm, height 0.18 mm, Site 209, core 1, section 1, Late Pleistocene; OS 14073, adult left valve, length 0.30 mm, height 0.19 mm, Site 209, core 2, section 2, Early Pleistocene.

Type locality and level. Lord Howe Rise, present day water depth 1389 m, DSDP Site 207A, core 1, section 1, interval 45-57 cm. Early Pliocene, Zone NN 14 .

Diagnosis. Eucytherura with valve surface bearing four lateral swellings or nodes as follows: a large, subcentral node of circular section; irregular, spinose posteroventral node; angular anterodorsal node; and an irregular posterodorsal node. A short, almost vertically aligned ridge present high on the dorsal surface close to midlength. Remainder of valve surface both primarily and secondarily reticulate.

Description. Small, subrectangular in lateral view. Anterior margin bluntly rounded, asymmetrical, extremity below mid-height with six well-spaced denticles, uppermost three strongest forming prominent blunt spines. Posterior margin convex with short caudal process just above mid-height. Dorsal margin straight to slightly convex, punctuated by tuberculate ornament. Ventral margin convex with a shallow oral incurvature just ahead of mid-length. Thick-shelled, not well inflated. Reticulate and tuberculate. Distinct tubercle just anteroventral of centre, circular in section with variable ridged or spinose rounded summit. Well-developed, irregular, longitudinally extended, spinose tubercle partially obscured by strong primary muri which form short conjunctive spines and ridges on the tubercle, at anterodorsal corner and high on the posterodorsal corner. Weak subvertical ridge extends between the ventral tubercles terminating mid-dorsally at a strong dorsal spine. Smooth, narrow ventro-lateral ridge curves from anteroventral corner, subparallel to ventral margin, terminates just ventral to an irregularly spinose posteroventral tubercle. Remainder of valve surface covered with irregular primary reticulation, and an almost equally strong secondary reticulum. Marginal rims narrow and smooth. Ventral surface primarily and coarsely secondarily reticulate; two thin costae occur in anterior field, these diverge toward mid-length subparallel to ventral margin. Numerous conjunctive pore conuli. Internal features as for genus.

Comparisons. Eucytherura multituberculata is similar in shape and tuberculate nature to Eucytherura complexa Brady, 1866 , a species widely distributed in shallow water. The reticulation of the latter species differs, however, in having a trefoil fossal pattern. Certain features of E. multituberculata are notably variable, particularly the strength of the secondary reticulation and development of the mid-dorsal spine. The latter feature is absent in specimens of Cretaceous to Eocene age of the Tasman Sea and those found on the Ita Mai Tai Guyot (DSDP Site 200).

Distribution. This species is known from the Tasman Sea in the Late Palaeocene to Pliocene of DSDP Site 207A, in the Late Cretaceous of DSDP Site 208; from the Coral Sea in the Miocene and Pleistocene of DSDP Site 209; from the Ita Mai Tai Guyot, western Pacific in the Miocene and Pleistocene ofDSDP Site 200; Late Pleistocene of Sonne 36 -61 and OSI 1-86/6GC3; Recent (coretop) of cores TS 8637 and TS 8655; and from the Pleistocene eastern Indian Ocean DSDP Sites 253 and 254. Occurrences outside the lndo-Pacific region include the Recent North Atlantic records of Cronin (1983) 1029 m from the Blake Plateau, western mid Atlantic; Davies (1981) from depths between 500 -2000 m of the north eastern Atlantic; and Whatley & Coles (1987) from abyssal depths in the central Atlantic in the Late Pliocene.

Figures

Fig. 5. Scanning electron micrographs. All scale bars are 100!lm. A-E, Eucytherura multituberculata n.sp., A, external lateral view of adult left valve (OS 14073), Early Pleistocene, B, ventral view of same specimen, C, internal view of adult left valve (MA/IP/404) from DSDP Site 209, core 2, section 2, Early Pleistocene, D, external lateral view of adult left valve (SD/WPP/329) from DSDP Site 207A, core 3, section 1, Early Pliocene, E, external lateral view of adult right valve (SD/WPP/330) from DSDP Site 207A, core 3, section 5, Early Pliocene; F-L, Hemiparacytheridea leopardina (Ruan & Hao, 1988), F, external lateral view of adult right valve (OS 14079), Late Pleistocene, G, external lateral view of adult left valve (OS 14077), Early Pleistocene, H, external lateral view of adult right valve (MA/IP/409) from DSDP Site 209, core 1, section 1, Late Pleistocene, I, external lateral view of adult left valve (SD/WPP/337) from DSDP Site