Yoldiella sp. (NHM_190)

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 : 12-14

Yoldiella sp. (NHM_190)

Material examined.

NHM_042 NHMUK 20170054, collected 2013-10-09, 13.8372 -116.55843, 4336 m. http://data.nhm.ac.uk/object/621deeed-8f8a-4d2e-9136-4e30794fc68e

NHM _185 NHMUK 20170055, collected 2013-10-13, 13.93482 -116.55018, 4082 m. http://data.nhm.ac.uk/object/6dfa8946-aa7a-448d-9f4f-703a3b2a10d9

NHM_190 NHMUK 20170056, collected 2013-10-13, 13.93482 -116.55018, 4082 m. http://data.nhm.ac.uk/object/b6e48ff4-2e02-42dc-b9ed-286d297d1459

NHM_193 NHMUK 20170060, collected 2013-10-13, 13.93482 -116.55018, 4082 m. http://data.nhm.ac.uk/object/8923576e-4542-4fc7-9a89-016e8fb564cb

NHM_194 NHMUK 20170057, collected 2013-10-13, 13.93482 -116.55018, 4082 m. http://data.nhm.ac.uk/object/7a6c76df-989b-4fcd-9e9c-a442d0a02443

NHM _246 NHMUK 20170058, collected 2013-10-16, 13.81166 -116.71, 4076 m. http://data.nhm.ac.uk/object/37b2493a-a725-4ec4-a720-cc9dd12fb49d

NHM_289 NHMUK 20170059, collected 2013-10-17, 13.75583 -116.48667, 4076 m. http://data.nhm.ac.uk/object/17d54bb4-9f38-4073-9bb6-17637773b058

Description.

Small, sub-ovate, longer than high, umbone at mid-line, dorsal margin horizontal to slightly curved, ventral margin deeply rounded, thin-shelled, shiny, semi-transparent, smooth except for growth increments. Internal features not investigated but 4-5 anterior and posterior chevron teeth. Hindgut visible though the shell forms a simple rounded loop on right side of body. DNA voucher NHM_190 shell length 1.6 mm, height 1 mm. Voucher specimen NHM_185 shell length 1.5 mm, height 1 mm (Fig. 11).

Genetic data.

GenBank NHM_042 18S-MF157467; NHM_185 18S-MF157480; NHM_190 18S-MF157482; NHM_193 18S-MF157484; NHM_194 18S-MF157485; NHM_246 18S-MF157486; NHM_289 18S-MF157492, COI-MF157517.

Remarks.

Extremely small, semi-transparent bivalves typically about 1 mm in size. Yoldiella species are particularly difficult to identify (see Killeen and Turner 2009). Forms a unique monophyletic clade distinct from all other AB01 specimens. No genetic matches on GenBank. In the molecular tree (Fig. 12) the genus Yoldiella is not monophyletic, and the present species does not group with another Eastern Pacific bathyal species, Yoldiella orcia (Dall, 1916), which instead forms a well-supported subclade with two Atlantic species.

Ecology.

Found in polymetallic nodule province.