Bathycadulus segonzaci, Scarabino, Victor, Caetano, Carlos Henrique Soares & Carranza, Alvar, 2011

Scarabino, Victor, Caetano, Carlos Henrique Soares & Carranza, Alvar, 2011, Three new species of the deep-water genus Bathycadulus (Mollusca, Scaphopoda, Gadilidae), Zootaxa 3096, pp. 59-63 : 61-62

Bathycadulus segonzaci new species

Figs 7−10

Type material. Holotype (lv) MNHN 24345 and 4 paratypes: 2 MNHN 24346 (1 lv, 1 dd), 2 MOM 291153 (1 lv, 1 dd). Type locality. Off Gulf of Gascony, 47°30'N, 0 9°32'W, 4287 m, [ INCAL, stn WS08]. Distribution. North-eastern Atlantic Ocean, off Gulf of Gascony. Live specimens from 4287−4387 m, empty shells from 4050 m.

Description. Shell 9 mm long, porcellaneous white. Maximum diameter occupying 3/5 medial zone, both sides almost parallel in dorsal view. Ventral side forming regular arch, more pronounced at anterior and posterior areas in lateral view. Dorsal side forming double sinusoidal wave due to presence of two slight bulges located in posterior and anterior limits of central area (lateral view). Apical, oral areas similarly in length, gradually constricted. Apex simple, slightly dorsoventrally compressed. Oral section laterally compressed.

Material examined. ABYPLAINE: stn CP18, 0 2°52'N, 15°33'W, 4330 m, 2 dd; BIOGAS IV: stn DS55, 47°34'N, 0 9°40'W, 4125 m, 2 dd; stn DS56, 47°32'N, 0 9°28'W, 4050 m, 1 dd; stn DS76, 47°31'N, 0 9°34'W, 4228 m, 2 dd; INCAL: stn WS08, 47°30'N, 0 9°33'W, 4287 m, 1 lv (Holotype) and 3 dd (1 Paratype); stn WS09, 47°28'N, 0 9°34'W, 4277m, 7 dd; stn WS10, 47°27'N, 0 9°39'W, 4354 m, 1 lv (Paratype), 5 dd; Princesse-Alice II: stn 2964, 46°17.30'N, 0 5°42'W, 4387 m, 1 lv (Paratype), 2 dd (1 Paratype).

Etymology. After Michel Segonzac (IFREMER) who provided most of specimens here studied.

Remarks. Bathycadulus segnozaci can be confused with Cadulus cylindratus Jeffreys , l877 ( Figs 11, 12 ), a sympatric species often captured in same stations, but no referable to Bathycadulus due its clear concave inner and convex outer profile all along the shell in lateral view, absence of oral and apical constrictions, thinner shell walls, apical section clearly dorsoventrally depressed, and apical callous thin.

Comments on geographic distribution of Bathycadulus . Although the limited number of samples does not allow to confirm the global geographic dispersal of the genus, its rather large distribution in bathyal and abyssal realms can be inferred.

Radulae. Comparing the radulae of B. fabrizioi [described on the basis of optical observation in Scarabino (1998: figs 160 m –n)] with that of B. segonzaci ( Figs. 9–10 ), the rachidian teeth are quite similar, although more pyramidal in B. segonzaci . The chain of denticles located in the external side of the head of laterals as well as the three main cusps are also similar, the main difference is the presence of four distinct denticles between the cusps in B. fabrizioi while B. segonzaci shows two small ones.

Figures

FIGURE 1 − 12. Genus Bathycadulus and Cadulus. (1 − 2) B. fabrizioi Scarabino, 1995 (Paratype MNHN), (1) lateral view and (2) dorsal view; (3 − 4) B. queirosi n. sp. (Holotype MNHN), (3) lateral view and (4) dorsal view; (5 − 6) B. hendersoni n. sp. (Holotype MCZ, 6.6 mm), (5) lateral view and (6) dorsal view; (7 − 8) B. segonzaci n. sp. (Holotype MNHN, 8.7 mm), (7) lateral view and (8) dorsal view; (9 − 10) Radula of B. segonzaci, (9) whole and (10) details of rachidian and lateral teeth; (11 − 12) Cadulus cylindratus Jeffreys 1877, (specimen from MNHN collection), Gulf of Gascony, 47 º 30 ' 6 N, 09 º 37 ' 1 W, 4281 m), (11) lateral view and (12) dorsal view. Scale bars: (9) 100 µm; (10) 20 µm.