Eucytherura tumida, 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 : 217-218

Eucytherura tumida n.sp.

Fig. 3 K-N

"? Typhlocythere tumida" Ayress, 1988 *: 638; pI. 22, figs 23- 24; pI. 23, figs 1-5.

Etymology. Latin. Referring to the tumid ventro-Iateral inflation of this species.

Type material and dimensions. Holotype, OS 14074, adult right valve, length 0.34 mm, height 0.22 mm. Paratypes: OS 14075, adult left valve, length 0.34 mm, height 0.20 mm, Site 254, core 1, section 2, interval 20 -26 cm, Pleistocene; OS 14076, adult left valve, length 0.33, height 0.20 mm, Site 254, core 1, section 3, interval 50 -56 cm, Pleistocene.

Type locality and horizon. East Indian Ocean , southern limit of Ninetyeast Ridge, present day water depth 1253 m, DSDP Site 254, core 1, section 2, interval 20 -26 cm, Pleistocene .

Diagnosis. A sub-rectangular to sub-ovate, ventro-Iaterally tumid species of Eucytherura . Strongly reticulate, fossae somewhat vertically aligned in posterior half, arranged in rows parallel to anterior margin in anterior half. Ventral surface conspicuously ornamented with microreticulation which extends to anterior and posterior marginal regions; ventral microreticulate field expanded in anterior half and regularly arranged between five primary mural rows.

Description. Small sized, sub-rectangular to sub-ovate in lateral view. Anterior margin bluntly convex; posterior margin with extremely short caudal process just below dorsal margin. Dorsal margin straight to slightly convex; ventral margin gently convex, oral incurvature indistinct. Moderately thick shelled and well inflated; tumid posteroventral swelling overhangs ventral margin. Coarsely reticulate: fossae deep and ovate, subvertically aligned in posterior half, concentrically aligned in anterior half; edges of muri rarely bear incipient ingrowing spines. Sinuous ventro-Iateral ridge borders primary reticulation and ventral microreticulation, the latter extends to anterior and posterior marginal regions. Anterior half of ventral surface with a conspicuous field of microreticulation infilling five rows of horizontally aligned thin primary muri. Normal pore canals numerous and well spaced. Internal pore clusters consist of clusters of 2 -3 pores. Other internal features as for genus.

Comparisons. This species differs from E. indianensis n.sp. primarily in its more ordered reticulum, less angular outline and lacks the longitudinal anterior ridge.

Distribution. Late Pliocene to Pleistocene ofDSDP Site 254 on the Ninetyeast Ridge, eastern Indian Ocean.