Bathyspinula calcar (Dall, 1908)

Wiklund, Helena, Taylor, John D., Dahlgren, Thomas G., Todt, Christiane, Ikebe, Chiho, Rabone, Muriel & Glover, Adrian G., 2017, Abyssal fauna of the UK- 1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca, ZooKeys 707, pp. 1-46 : 7-8

Bathyspinula calcar (Dall, 1908)

Material examined.

NHM_146 NHMUK 20170044, collected 2013-10-11, 13.75833 -116.69852, 4080 m. http://data.nhm.ac.uk/object/61f15e3c-f070-48a1-b484-780b37f7feb6

NHM _149A NHMUK 20170045, collected 2013-10-11, 13.75833 -116.69852, 4080 m. http://data.nhm.ac.uk/object/c44da298-9b61-4d6d-a1cd-2d6c3bd70859

NHM_181 NHMUK 20170043, collected 2013-10-13, 13.93482 -116.55018, 4082 m. http://data.nhm.ac.uk/object/3ab74908-1a5d-465f-890c-49373a44906c

NHM_284 NHMUK 20170046, collected 2013-10-17, 13.75583 -116.48667, 4076 m. http://data.nhm.ac.uk/object/ad2cb87b-1fce-415d-ab45-1619bbc4352b

Description.

Shell sub-ovate, laterally compressed, with long, sharply pointed posterior rostrum. Periostracum shiny, medium brown. Posterior rostrum shorter, less defined in juveniles. Voucher specimen NHM_181 shell length 13.5 mm, width 7.6 mm (Fig. 6A).

Genetic data.

GenBank NHM_146 18S-157475, COI-MF157505; NHM_149A COI-MF157506; NHM_181 18S-MF157479, COI-MF157507; NHM_284 COI-MF157514.

Remarks.

Widely distributed in the eastern Pacific at depths of 400-5000 m (see Coan and Valentich-Scott 2012). The holotype (USNM 110573) was collected 725 km west of Trujillo, Peru at 2370 fathoms (4334 m). Forms a unique monophyletic clade distinct from all other AB01 specimens. Genetic match in 18S to Bathyspinula calcar (GenBank KC993875) from the north eastern Pacific ( Sharma et al. 2013), but as the GenBank 18S sequence from B. calcar was only 289 bp long and as that specimen lacked COI, it was not included in the analyses. Some very small juvenile specimens (Fig. 6 B–D) were recovered that superficially resemble Ledella knudseni sp. n. (Fig. 7) and may be easily confused. Genetic data confirmed these to be Bathyspinula calcar (Fig. 12). These may be distinguised from Ledella by the shiny and iridescent nature of the shell surface of B. calcar , which is preserved in the juveniles.

Ecology.

Relatively large bivalve recovered from epibenthic sledge tow in polymetallic nodule province.