Nipponithyris afra Cooper, 1973

Bitner, Maria Aleksandra & Romanin, Marco, 2017, Recent brachiopods from the South China Sea, NW Pacific, Zootaxa 4306 (2), pp. 287-290 : 289

Nipponithyris afra Cooper, 1973 ( Fig. 1 H–R)

2016 Nipponithyris afra Cooper—Bitner & Logan , p. 28, fig. 16 (cum syn.).

Material examined. DongSha 2014 cruise, stn CP 4130, 20°16’N, 116°08’E, depth 795–822 m, six specimens.

Measurements. Maximum length 15.0 mm, width 12.7 mm, thickness 7.1 mm.

Description. Shell of medium size, subpentagonal in outline, longer than wide, ventribiconvex with smooth surface and strongly unisulcate anterior commissure. Beak erect with weakly defined beak ridges. Foramen circular, mesothyrid to permesothyrid. Deltidial plates conjunct forming a visible symphytium. Shell posteriorly strongly thickened ( Fig. 1 N– R). Ventral valve interior with short, thick teeth with swollen bases; delthyrial cavity narrow. Dorsal valve interior with massive inner socket ridges. Cardinal process prominent. Crura short. Descending branches slender becoming broad anteriorly. Septum short.

Remarks. The specimens correspond well with those described as Nipponithyris afra . This species was first recorded by Cooper (1973a) from off Mozambique (see also Bitner & Logan 2016) and later recognized in the New Caledonian region ( Laurin 1997). Nipponithyris afra differs from N. nipponensis Yabe & Hatai, 1934 that is found off the coasts of Japan in being rounder and in having a more strongly sulcate anterior commissure ( Hatai 1940, Cooper 1973a).

Figures

FIGURE 1. A – B. Terebratulina japonica (Sowerby, 1846), dorsal views of complete specimens, stn DW 4125, 305 – 306 m, SEM, MNHN IB- 2013 - 640. C – G. Macandrevia sp., one complete specimen, stn CP 4123, 1612 – 1665 m, MNHN IB- 2013 - 641. C – D. Dorsal and lateral views of complete specimen. E – F. Ventral valve of the same specimen, posterior part of interior and tilted view to show strong dental plates, SEM. G. Interior view of dorsal valve to show cardinalia, SEM. H – R. Nipponithyris afra Cooper, 1973, stn CP 4130, 795 – 822 m. H – M. Dorsal, lateral and anterior views of two complete specimens, MNHN BI- 2013 - 642. N – O. Posterior part of ventral valve interior and tilted view to show swollen bases and grooves to accommodate inner socket ridges, SEM, MNHN BI- 2013 - 643. P. Interior of dorsal valve, partly broken loop visible, SEM, MNHN BI- 2013 - 644. Q – R. Posterior part of dorsal valve interior and enlargement to show details of strongly thickened cardinalia, SEM MNHN BI- 2013 - 645.