Abyssal fauna of the UK- 1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca Author Wiklund, Helena Author Taylor, John D. Author Dahlgren, Thomas G. Author Todt, Christiane Author Ikebe, Chiho Author Rabone, Muriel Author Glover, Adrian G. text ZooKeys 2017 707 1 46 http://dx.doi.org/10.3897/zookeys.707.13042 journal article http://dx.doi.org/10.3897/zookeys.707.13042 1313-2970-707-1 6A0BCD992749450C874B440D0C0A232C Nucula profundorum Smith, 1885 Material examined. NHM_141 NHMUK 20170051, collected 2013-10-11, 13.75833 -116.69852, 4080 m. http://data.nhm.ac.uk/object/f2133256-1cad-4255-a5cb-bd5331417127 NHM_274A NHMUK 20170052, collected 2013-10-17, 13.75583 -116.48667, 4076 m. http://data.nhm.ac.uk/object/f96a470e-237e-46b4-ba85-4c6196106071 NHM_378 NHMUK 20170053.1-2, collected 2013-10-19, 13.93307 -116.71628, 4182 m. http://data.nhm.ac.uk/object/65f8d1ed-dd6a-4265-90d2-daf07491cd76 Description. Small, trigonal- subovate. Periostracum light brown, shiny. Sculpture of fine radial lirae. Resilifer small. Hinge teeth: 5 anterior, 4 posterior. Inner shell margin finely denticulate. Voucher NHM_274A width 2 mm, height 1.8 mm (Fig. 9). Figure 9. Nucula profundorum Smith, 1885 A Live specimen NHM_141 (for which 18S, CO1 and 16S sequences were obtained) B Live specimens NHM_274 (4 specimens from same sample) C Open shell from single individual NHM_274A with tissue sample taken for DNA sequencing D-E SEM of NHM_378 valve showing hinge teeth. Scale bars: 1.5 mm (B); 0.5 mm (C). Image attribution Glover, Taylor, Dahlgren & Wiklund, 2017. Genetic data. GenBank NHM_141 16S-MF157457, 18S-MF157473, COI-MF157503; NHM_274A COI-MF157512; NHM_378 16S-MF157464, COI-MF157520. Remarks . Morphologically matches Nucula profundorum Smith, 1885 based on examination of the syntype specimens [NHMUK 1887.2.9.2919]. In the molecular analysis of nuculoid protobranchs (Fig. 12) Nucula profundorum and the Atlantic Nucula atacellana Schenck, 1939 are well supported sister species. However the N. profundorum identified from the present samples differs genetically from the N. profundorum record in GenBank (accession nr KJ950274; Jennings and Etter 2014 ) which we believe may be misassigned. That sample came from 1045 m in the north eastern Pacific off San Diego (Figure 10). The shell illustrated by Coan and Valentich-Scott (2012 pl 12) as N. profundorum has more hinge teeth. There may be a complex of morphologically similar species in the eastern Pacific. No genetic matches on GenBank. Figure 10. Nucula profundorum Smith, 1885. A-D Syntype BMNH 1887.2.9.2919, scalebars 1mm E Type locality (red) of N. profundorum from Challenger Expedition in relation to ABYSSLINE sampling location (green) and GenBank voucher specimen sampling location (white). Bathymetric data (D) from NOAA. Ecology. The most abundant bivalve mollusc recorded in the ABYSSLINE sampling programme, frequently found in epibenthic sledge and box core samples from region of sediment and polymetallic nodules.