A new genus Turneroconcha (Bivalvia: Vesicomyidae: Pliocardiinae) for the giant hydrothermal vent clam ‘ Calyptogena’ magnifica Author Krylova, Elena M. Shirshov Institute of Oceanology, Russian Academy of Sciences, Nahimovskiy Prospekt, 36, Moscow, 117997, Russia elenamkr @ mail. ru; https: // orcid. org / 0000 - 0003 - 1341 - 1709 Author Sahling, Heiko text Zootaxa 2020 2020-07-01 4808 1 79 100 journal article 10.11646/zootaxa.4808.1.4 1175-5326 3927938 6CF17F6B-78D0-4BE6-8241-FB9B8C1E0B39 Genus Turneroconcha gen. nov. Genus N 1—Krylova & Sahling, 2010: 6. Type species. Calyptogena magnifica Boss & Turner, 1980 . Derivation of name. The genus is dedicated to the outstanding American malacologist Prof. Ruth D. Turner, one of the authors of the original description of Calyptogena magnifica , in acknowledgement of her investigations of bivalve molluscs. The gender is feminine. Diagnosis. Shell large, length to 270 mm , subovate-elongate in outline. Equivalve, inequilateral; umbos prosogyrate. No escutcheon and lunular incision. Pallial line starting from postero-ventral margin of anterior adductor scar and ending on postero-ventral margin of posterior adductor scar; weakly marked in its posterior region. Pallial sinus absent. Ligament strongly developed, external, parivincular. Posterior part of the posterior lamellar layer attached to shelf-like continuation of nymph that deeply submerges below dorsal shell margin. No subumbonal pit. Hinge teeth radiating. Right valve with strong anterior cardinal (1) and smaller subumbonal cardinal consisting of single posterior 3b ramus. Left valve with subumbonal cardinal tooth consisting of thin 2a ramus, fused by thin low bridge with higher and stronger wedge-shaped 2b ramus. Postero-dorsal cardinal 4b reduced to different degree, sometimes totally. Inner margin of valve thin, without any grooves. Ctenidia comprising both inner and outer demibranchs; interlamellar septa with a tubular structure in its marginal parts. Exhalant and inhalant siphonal tubes short. Inner valve of inhalant siphon without processes. Inner mantle fold 3 with tentacles. Digestive tract not linear, changing direction twice in midgut. Species included. The type species only: Turneroconcha magnifica comb. nov. ( Boss & Turner, 1980 ). Distribution. Pacific Ocean, the East Pacific Rise from 23ºN to 18ºS, Galapagos Rift, depth 2251–2791 m ( Table 3 , Fig. 1 ). TABLE 1. Turneroconcha magnifica comb. nov. ( Boss & Turner, 1980 ), material examined. Abbreviations: DSV, deep submergence vehicle; HOV, human-occupied vehicle; IORAS, P.P. Shirshov Institute of Oceanology, Moscow; ROV, remotely operated vehicle; RV, research vessel; Spm(s), specimen(s) live-collected; NMNH, National Museum of Natural History, Smithsonian Institution, Washington DC; V(s), valve(s).

Cruise	Year	Station/dive	Number of specimens; location of the material; voucher numbers	Area
RV Lulu, cruise 103-5, DSV ALVIN	1979	Alvin dive 990, 0º48.24’N, 86º22.47’W, 2451 m	2 vs; NMNH 807717	Pacific, Galapagos Rift
RV Akademik Mstislav Keldysh, 22 cruise, HOV MIR	1990	St. 2370, MIR 25/69, 20º50.40’N, 109º05.80’W, 2640 m	2 spms; IORAS, BIV00028	Pacific, East Pacific Rise
RV Akademik Mstislav Keldysh”, 49 cruise, HOV MIR	2003	St. 4623, 9º50.97’N, 104º17.59’W, 2517 m; St. 4642, 9º50’N, 104º17’W, 2506 m; St. 4669, 9º50.53’N, 104º17.52’W, 2524 m; St. 4679, 20º49.86’N, 109º06.20’W, 2601m	3 spms; IORAS, BIV00029 6 spms; IORAS, BIV00030 1 spm; IORAS, BIV00031 1 spm; IORAS, BIV00032	Pacific, East Pacific Rise
RV Western Flyer, ROV Doc Ricketts	2015	D752, 23º21.43’N, 108º32.53’W, 2293 m;	10 paired vs; IORAS, BIV00033; 2 spms; IORAS, BIV00038	Pacific, Gulf of California, Alarcón Rise
D753, 23º21.17’N, 108º33.58’W, 2251 m;	1 spm; IORAS, BIV00034
D754, 23º22.62’N, 108º31.87’W, 2309 m	5 paired vs; IORAS, BIV00035 7 spms; IORAS, BIV00036

TABLE 2. Additional material of Pliocardiinae studied. Abbreviations: SBMNH, Santa Barbara Museum of Natural His- tory, Santa Barbara, USA . Species Source of material Ectenagena elongata ( Dall, 1916 ) RV Western Flyer , ROV Tiburon , Dive T 592, 26° 88’ N, 111°65’ W, 818 m , Gulf of California , 19 May 2003 , 4 spms, IORAS ‘ Callocardia ’ stearnsii Dall, 1895 RV Point Lobos , ROV Tiburon , Dive T 3374, 36°48’ N , 121°59’ W , 635 m , Monterey Canyon, 3 June 2009 , 5 spms, SBMNH ‘ Calyptogena ’ ponderosa Boss, 1968 RV Atlantis , DSV Alvin , Dive A 4178, 28°07’ N , 89°08’ W , 1075 m , Gulf of Mexico , Mississippi Canyon , 14 May 2006 , 5 spms, IORAS