Diversity of chemosymbiotic bivalves on coral reefs: Lucinidae (Mollusca, Bivalvia) of New Caledonia and Lifou Author Glover, Emily A. Author Taylor, John D. Department of Zoology, The Natural History Museum, London SW 7 5 BD (United Kingdom) emily. glover @ dial. pipex. com j. taylor @ nhm. ac. uk taylor@nhm.ac.uk text Zoosystema 2007 29 1 109 181 journal article 10.5281/zenodo.5392295 1638-9387 5392295 Bretskya scapula n. sp. ( Figs 39B ; 40 ; 41 ) TYPE MATERIAL. — Holotype : 1 sh, L 6.8 mm , H 4.4 mm , T 1.4 mm ( BMNH 20050579 ). Paratypes : from type locality, 1 sh, L 6.8 mm , H 5.5 mm , T (2v) 3.2 mm ( BMNH 20050580 ) ; 1 sh, L 6.7 mm , H 6.2 mm , T(2v) 3.3 mm ( Conchology Inc. Reference Collection , Philippines ). — Figured paratypes : from type locality, 1 sh, L 6.3 mm , H 5.6 mm , T 1.6 mm ( MNHN ) ; 1 sh, L 5.0 mm, H 3.8 mm , T (2v) 2.2 mm ( BMNH 20050580 ) ; 1 sh, L 6.8 mm , H 6.1 mm , T (2v) 3.2 mm ( BMNH 20050580 ) ; 1 sh, L 6.0 mm, H 4.5 mm , T (1v) 1.3 mm ( BMNH 20050580 ) ; 1 sh, L 4.0 mm, H 3.0 mm, T (2v) 1.9 mm ( BMNH 20050580 ) . TYPE LOCALITY. — Philippines , Pipe Point, Pandanan Island, Jetafe, Bohol , 10°10.34’N , 124°05.94’E , 5 m , muddy sand, 12.III.2005 , col. P. Poppe. ETYMOLOGY. — Latin scapula , shoulder blade – in reference to the shape of this bivalve. MATERIAL EXAMINED. — Touho. Stn 1249, 20°49’S , 165°19’E , 80-140 m , 1 RV, L 8.5 mm , H 7.7 mm ( MNHN ). Philippines . MUSORSTOM 3, stn DR 140, 11°43’N , 122°34’E , 93-99 m , 8 v ( MNHN ). DISTRIBUTION. — Recorded only from Philippines and New Caledonia at depths from 5- 100 m . DESCRIPTION Small, thin-shelled, H to 6.9 mm , L to 8.4 mm , outline irregular elongate ovoid, truncate to sinuate posteriorly, longer than high, H/L 0.68-0.82; highly anteriorly extended, slightly inflated. Umbones prominent, usually in posterior part of shell. Protoconch 160 µm long, PI 85 µm. PII with marked growth increments. Shell sculpture of irregular, thin, low, commarginal lamellae and fine growth increments, shell surface often distorted and plicate. Anterior dorsal margin elongate. Posterior dorsal margin steeply sloping. Lunule narrow, lanceolate. Ligament large, set on elongate resilifer. Hinge with two small, cardinal teeth in left valve and one in right valve, lateral teeth absent. Anterior adductor muscle scar short, reniform, detached from pallial line for about 1/3 of length. Pallial line entire. Shell margin smooth. FIG. 40. — Bretskya scapula n. gen., n. sp. : A -J , Pandanan Island, Philippines; A -C , holotype (BMNH 20050579),exterior of right valve and interior of right and left valves; D -J , paratype (BMNH 20050580); D -F , exterior of right valve and interior of right and left valves; G , exterior of right valve; H , exterior of right valve; I , J , detail of hinges of left and right valves; K , L , Philippines, MUSORSTOM 3, stn DR 140, 93-99 m (MNHN); M , N , Touho, stn 1249, New Caledonia, exterior and interior right valve. Scale bars: A-H, K-N, 2.0 mm; I, J, 1.0 mm. FIG. 41.— Bretskya scapula n. gen.,n. sp. , Pandanan Island, Philippines: A , dorsal view of paratype (BMNH 20050580); B , protoconch; C , detail of sculpture. Scale bars: A, 1 mm; B, 50 µm; C, 100 µm. REMARKS The material from the Philippines , on which this new species and genus is based, consists of seven livecollected shells. The characters are highly distinctive and unlike any other known lucinid. Although we have only a single right valve of this species from New Caledonia , it matches the characters of the type specimens.