Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific Author Valdés, Ángel John T. Huber text Mémoires du Muséum national d'Histoire naturelle 2008 196 587 792 journal article 978-2-85653-614-8 1243-4442 Relichna hadra n. sp. Figs 84C, D, 85B, 86B, 90 TYPE MATERIAL . — Holotype MNHN 20398 and 6 paratypes MNHN 20399-20404, 1 paratype LACM 3008 . TYPE LOCALITY . — Norfolk Ridge , 24°55’S , 168°22’E , 513 m [ SMIB 3 : stn DW 3 ] . MATERIAL EXAMINED. — Norfolk Ridge . BIOCAL: stn DW 51 , stn DW 3 , 24°55’S , 168°22’E , 513 m , 2 dd, holotype ( MNHN 23°05’S , 167°45’E , 680-700 m , 1 dd, paratype ( MNHN 20400); 20398; Figs 84C, D) and paratype ( MNHN 20399) . — SMIB 8 : stn DW 53 , 23°09’S , 167°43’E , 975-1005 m , 1 dd, paratype stn DW 149 , Mont B , Banc Eponge, 24°55’S , 168°22’E , 508- ( MNHN 20401); stn DW 66 , 24°55’S , 168°22’E , 505-515 m , 1 510 m , 1 dd, paratype ( MNHN 20404); stn DW 152 , 24°54’S , dd, paratype ( MNHN 20402); stn DW 70 , 23°25’S , 167°53’E , 168°22’E , 514-530 m , 1 dd, paratype ( LACM 3008 ) . 965 m , 1 lv , paratype ( MNHN 20403; Figs 85B, 86B) . — SMIB 3 : DISTRIBUTION . — Collected from New Caledonia (Fig. 90), in 510-975 m , live in 965 m . DESCRIPTION. — Shell morphology. Length 11 mm , width 6 mm (largest specimen examined). Shell solid, short, and oval, with a right concave side and a left convex side (Fig 84C). Only 1 whorl visible, forming nearly the entire shell, except for a small visible portion of the top of the spire. Apex flat, umbilicate (Fig. 84D). Aperture lip rising from the left side. The aperture lip forms a rounded wing connected to the columellar margin. Anterior end of the shell rounded. Aperture as long as the shell, wider anteriorly and narrowing gradually at about 1/2 of its length. Columellar margin slightly thickened. Columella with 1 small fold. Umbilicus narrow, partially covered by a columellar extension. Sculpture of a number of inconspicuous growth lines. Colour uniformly dirty white. Anatomy . The digestive system contains 3 smooth, unequal gizzard plates (Fig. 85B). There is no radula. The reproductive system contains a complex ejaculatory duct connected to a spermatic bulb and the prostate (Fig. 86B). The female and hermaphroditic organs are unknown. REMARKS. — This species is assigned to the genus Relichna because of the absence of radula and jaws and the presence of 3 smooth and unequal gizzard plates. Relichna hadra is clearly distinguishable from other species of Relichna here reviewed by the twisted shape of the shell with a right concave side and a left convex side. Also, the reproductive anatomy is clearly distinct, with a complex ejaculatory duct connected to a spermatic bulb and the prostate. Relichna murdochi Suter, 1913 , the type species of the genus, also has a spermatic bulb (Rudman 1971), but the ejaculatory duct is short and simple. ETYMOLOGY. — From the Greek adjective hadros (thick, bulky, strong), in reference to the thick and large shell of this species.