Septicollarina zezinae, Bitner, Maria Aleksandra, 2009

Bitner, Maria Aleksandra, 2009, Recent Brachiopoda from the Norfolk Ridge, New Caledonia, with description of four new species, Zootaxa 2235, pp. 1-39 : 24-25

publication ID	https://doi.org/ 10.5281/zenodo.190398
DOI	https://doi.org/10.5281/zenodo.6225374
persistent identifier	https://treatment.plazi.org/id/0394A818-6615-8207-FF59-D1D4FA9299DD
treatment provided by	Plazi
scientific name	Septicollarina zezinae
status	sp. nov.

Treatment

Septicollarina zezinae View in CoL sp. nov.

( Fig. 8 View FIGURE 8 A–N)

Septicollarina sp. – Bitner, 2008: 437–439, fig. 16A.

Material examined. Norfolk 2 cruise: Jumeau East seamount, Stn DW 2053, two complete specimens; Stn DW 2055, three complete specimens. Porthos seamount, Stn DW 2069, two complete specimens. Zorro seamount, Stn DW 2080, one complete specimen.

Holotype. The specimen in Figure 8 View FIGURE 8 J–N ( MNHN BRA- 3153).

Paratypes. The specimens in Figures 8 View FIGURE 8 A–I ( MNHN BRA- 3154–3157).

Type locality. Jumeau East seamount, Norfolk Ridge, 23°39.23’ S, 168°16.43’ E, 900– 950 m.

Etymology. In honour of renowned brachiopod specialist Professor Olga N. Zezina (P. P. Shirshov Institute of Oceanology, Moscow).

Diagnosis. Medium-sized Septicollarina , transversely pentagonal in outline and strongly unisulcate. Shell surface smooth with faint radial lines and rare, randomly distributed, small pustules. Beak short, erect to incurved. Foramen permesothyrid, circular, deltidial plates minute. Wide pedicle collar supported by dental plates and short ventral septum. No cardinal process. Loop diploform, anteriorly weakly spinose.

Depth range. 670– 950 m.

Measurements. (in mm).

Description. Shell medium sized, thin, ventri-biconvex, transversely pentagonal with greatest width at about mid-length. Shell surface smooth with very faint radial lines and rare, randomly distributed, small pustules ( Fig. 8 View FIGURE 8 G, N); pustules more numerous on ventral valve. Lateral commissures dorsally curved, anterior commissure strongly unisulcate. Beak short, erect to incurved, abraded with well-defined beak ridges. Pedicle short, massive, terminally divided. Foramen large, circular, permesothyrid. Deltidial plates minute. Ventral valve interior with small teeth supported by strong, well-developed dental plates. Pedicle collar very wide, supported by short median septum ( Fig. 8 View FIGURE 8 I). Dorsal valve interior with long medium septum, high posteriorly, low anteriorly. Inner hinge plates attached to septum, forming septalium. No cardinal process observed. Crura very thin, relatively long. Descending branches narrow, parallel. Both crura and descending branches very delicate, prone to breaking while removing soft tissue. Ascending branches very broad like transverse band. Loop weakly spinose anteriorly. Muscle scars strongly defined on both valves.

Remarks. The specimens bear all the characters typical of the genus Septicollarina ( Zezina 1981a, 1990). Two other species are known ― S. hemiechinata Zezina, 1981 a from off Java and S. oceanica Zezina, 1990 from the Eastern Pacific. The specimens from the Norfolk Ridge are twice as large as these species, but closely resemble Septicollarina sp. from Fiji (Bitner 2008), which is here considered to be synonymous with S. zezinae .

Externally, the new species differs from the other Septicollarina species in the shell surface, the strongly unisulcate anterior commissure and the incurved beak. In addition, the Norfolk species differs from S. hemiechinata in having a longer ventral septum, which in S. hemiechinata is equal to the length of the pedicle collar ( Zezina 1981a). Also the loop in S. zezinae is more weakly spinose anteriorly than in S. hemiechinata and S. oceanica . The two latter species were collected at depths of 240 m and 350–470 m, respectively ( Zezina 1981a, 1990), while S. zezinae has a bathymetric range of 557–950 m (see also Bitner 2008).