Cylichna tanyumphalos, Valdés, 2008

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 661-663

publication ID

978-2-85653-614-8

persistent identifier

https://treatment.plazi.org/id/03D087B2-FFAE-BE62-FF01-7202F695FCAE

treatment provided by

Felipe

scientific name

Cylichna tanyumphalos
status

sp. nov.

Cylichna tanyumphalos View in CoL n. sp.

Figs 34, 35C, D, G

TYPE MATERIAL. — Holotype MNHN 20359 and 12 paratypes MNHN 20360-20362, 1 paratype LACM 2991 View Materials .

TYPE LOCALITY . — Norfolk Ridge , 24°44’S, 168°07’E, 430-450 m [ BERYX 11 : stn CP 21] GoogleMaps .

MATERIAL EXAMINED. — New Caledonia proper. VAUBAN: paratype ( MNHN 20361 View Materials ) . — BATHUS 2 : stn DW 717 , Ile des stn 40, 22°30’S, 166°24’E, 250-350 m, 1 dd, paratype ( LACM Pins, 22°44’S, 167°17’E, 350-393 m, 1 dd, paratype. — BATHUS 2991 ) GoogleMaps . — BATHUS 1 : stn DW 654 , Passe du Cap Baye , 21°17’S, 3: stn DW 838 , 23°01’S, 166°56’E, 400-402 m, 1 dd, paratype 165°57’E, 237-298 m, 9 dd & lv, 1 of them destroyed to dis- ( MNHN 20362 View Materials ) GoogleMaps .

sect the radula, paratypes (MNHN 20360; Fig. 35G); stn DW Norfolk Ridge. BERYX 11: stn CP 21, 24°44’S, 168°07’E, 430- 688, Passe de Hienghu, 20°33’S, 165°00’E, 270-282 m, 1 dd, 450 m, 1 dd, holotype (MNHN 20359; Figs 35C, D).

DISTRIBUTION. — Collected from New Caledonia (Fig. 34), in 282-430 m.

DESCRIPTION. — Shell morphology. Length 6 mm, width 2 mm (holotype). Shell fragile, elongate, narrow anteriorly, with nearly parallel sides (Fig. 35C). Only 1 whorl visible, forming nearly the entire shell. Apex rounded, with a deep umbilicus partially covered by the columellar margin (Fig. 35D), with the aperture lip rising from the left side and forming a short wing connected to the columellar margin. Anterior end of the shell elongate. Aperture as long as the shell, wider anteriorly and narrowing gradually at about 1/10 of its length and again at 1/5 of its length. Columellar

FIG. 35. Shell morphology and anatomy of species of Cylichna Lovén, 1846 . A, Cylichna consobrinoides Kuroda & Habe, 1952 , (14 mm), ventral view, Coral Sea, MUSORSTOM 5 stn 265; B, same shell, posterior view. C, Cylichna tanyumphalos n. sp., holotype MNHN 20359 (6 mm), ventral view, New Caledonia, BERYX 11 stn CP 21; D, same shell, posterior view. E, Cylichna grovesi n. sp., holotype MNHN 20352 (6 mm), ventral view, VAUBAN stn 40; F, same shell,posterior view. G, Cylichna tanyumphalos n. sp.,radula of paratype MNHN 20360, New Caledonia,BATHUS 1 stn DW 654, scale bar = 20 Μm. H, Cylichna grovesi n. sp.,radula of paratype MNHN 20356, New Caledonia, BATHUS 2 stn CP 743,scale bar = 20 Μm.

margin thickened. Columella with one fold. Umbilicus long and deep. Sculpture of faint growth lines. Colour uniformly dirty white.

Anatomy. The digestive system contains 3 smooth gizzard plates similar in shape and size. The radular formula is 16 x 2.1.1.1. 2 in a paratype from New Caledonia (BATHUS 1 stn DW 654). The rachidian teeth are broad, with several short denticles decreasing in size towards the laterals of each plate (Fig. 35G). There is a gap with no denticles on the centre of each rachidian tooth. The innermost lateral teeth are hook-shaped, with a long, strong cusp with 8- 10 denticles. The 2 outermost teeth of each row are much smaller, also hook-shaped and have small denticles.

REMARKS. — The shell morphology of this species differs from that of other Indo-Pacific members of the genus. The long umbilicus and the shape of the aperture, with 2 separate narrowings are its most distinctive features. Adamnestia teramachii Habe, 1954 from Japan, illustrated by Hori (2000b), also has a deep umbilicus but the shell is much shorter.

Cylichna tanyumphalos is assigned to the genus Cylichna because of the presence of 3 smooth and oval gizzard plates and a radula with a denticulate rachidian tooth and several hook-shaped and denticulate lateral teeth.

ETYMOLOGY. — From the ancient Greek tany (long) and umphalos (umbilicus), in reference to the long apical umbilicus of this species.

LACM

Natural History Museum of Los Angeles County

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Cephalaspidea

Family

Cylichnidae

Genus

Cylichna

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