Morphological descriptions from the recent bivalve of the genus Calyptogena (Vesicomyidae)

• Main Authors: Krylova, Elena M, Sahling, Heiko
• Format: Dataset
• Language: English
• Published: PANGAEA 2006
• Subjects: 103; 121GTVA; 123; 134; 231; 2646; 3077; 33; 569; 63; Akademik Mstislav Keldysh; AKM22-2320_15-28; Albatross_Stn_3077; ALVIN; AMK12; AMK12-1505; Atlantis_131; Atlantis_131_2646; Atlantis II (1963); Axial Seamount; Juan de Fuca Ridge; Center for Marine Environmental Sciences; East Atlantic; East of north Sakhalin; East Pacific; East Pacific Ocean; Dixon Entrance; Gagara_231; GE99/KOMEX_VI; GE99-25-1; GE99-28-1; GEOPECO; Grab_BGR Video A; GTVA; HYDROTRACE; M54/3A; M54/3A_123; M54/3A_134; MAKRAN 2; Marshal Gelovany; MARUM; Meteor (1986); MIR-2; MIR-2 deep-sea manned submersible; MULT; Multiple investigations; Obzhirov flare; PISCES; S2000; Pacific; Indian; Krylova; Sakhalin
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.771121; https://doi.org/10.1594/PANGAEA.771121

The genus Calyptogena (Bivalvia: Vesicomyidae) comprises highly specialized bivalves living in symbiosis with sulphur-oxidizing bacteria in reducing habitats. In this study, the genus is revised using shell and anatomical features. The work is based on type material, as well as on the extensive collection of vesicomyids obtained during twelve expeditions to the Pacific and Indian Oceans. Nine Recent species are ascribed to the genus Calyptogena, four of which are new: C. pacifica Dall, 1891, C. fausta Okutani, Fujikura & Hashimoto, 1993, C. rectimargo Scarlato, 1981, C. valdiviae (Thiele & Jaeckel, 1931), C. gallardoi Sellanes & Krylova, 2005, C. goffrediae n. sp., C. starobogatovi n. sp., C. makranensis n. sp. and C. costaricana n. sp. The characteristic features of Calyptogena are: shell up to 90 mm in length, elongate-elliptical or elongate; presence of escutcheon; presence of broad posterior ramus (3b) of right subumbonal cardinal tooth as well as right posterior nymphal ridge; absence of pallial sinus as a result of attachment of intersiphonal septal retractor immediately adjacent to ventral surface of posterior adductor; absence of processes on inner vulva of inhalant siphon; presence of inner demibranch only, with descending and ascending lamellae with interlamellar septa not divided into separate tubes. The most closely related taxa to Calyptogena are probably the genus Isorropodon Sturany, 1896, and the group of species represented by 'Calyptogena' phaseoliformis Métivier, Okutani & Ohta, 1986. These groups have several characters in common, namely absence of pallial sinus, presence of single inner pair of demibranchs and absence of processes on inner vulva of inhalant siphon. The worldwide distribution of the genus Calyptogena suggests that methane seeps at continental margins are the major dispersal routes and that speciation was promoted by geographical isolation. Recent species diversity and fossil records indicate that the genus originated in the Pacific Ocean. Sufficient data to ...