Gladiobela angulata, Criscione & Hallan & Puillandre & Fedosov, 2021

Criscione, Francesco, Hallan, Anders, Puillandre, Nicolas & Fedosov, Alexander, 2021, Where the snails have no name: a molecular phylogeny of Raphitomidae (Neogastropoda: Conoidea) uncovers vast unexplored diversity in the deep seas of temperate southern and eastern Australia, Zoological Journal of the Linnean Society 191, pp. 961-1000 : 987

GLADIOBELA ANGULATA SP. NOV.

( FIGS 4A, 6B)

Z o o B a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: F40216C9-F620-49A9-B91E-A91F118F7DF8.

Holotype: Australia, New South Wales, Hunter CMR, 2595 m, IN2017_ V03 _070, (–32.575, 153.162), one wet ( AMS C.571651).

Paratypes: Australia, GAB, 3350 m, IN2017_C01_197, (–34.452, 129.492) , one wet ( AMS C.571737); one wet ( AMS C.571735); one wet ( AMS C.571738); one wet ( AMS C.572166); one wet ( AMS C.572167); one wet ( AMS C.572168); one wet ( SAMA D49343); 3540 m, IN2017_C01_198, (–34.574, 129.572) , one wet ( SAMA D49341); one wet ( SAMA D67750); one wet ( SAMA D67751); 3807 m, IN2017_C01_192, (–34.589, 129.418) .

Distribution: Known from the Great Australian Bight and one locality off the Hunter Commonwealth Marine Reserve, New South Wales.

Etymology: The epithet is derived from the Latin adjective angulatus, angular, referring to the distinct angulation at its whorl periphery.

Description

Shell ( Fig. 4A) (SL = 18.8, SW = 10.2) broadly fusiformbiconical, thin-walled, semitranslucent. Protoconch (based on SAMA D49341) orange, first whorl(s) strongly eroded, subsequent 1.5 whorls with diagonally cancellate sculpture on abapical third, above with arcuate sculpture only. Clear protoconch–teleoconch boundary marked by deep sinus. Teleoconch of about 4.5 uniformly honey-coloured whorls, suture impressed. Whorls broad, with wide, slightly concave subsutural ramp; well-defined, prominent shoulder situated at approximately mid-height to just below mid-height of whorl. Axial sculpture of growth lines only, on early whorls forming slightly raised, densely set riblets. Spiral sculpture of densely set, evenly spaced subperipheral cords (about eight on penultimate whorl,> 30 on last whorl), few weak cords present immediately above shoulder. Last adult whorl with slight concavity immediately below subsutural ramp, below evenly convex, clearly demarcated from slightly tapering, long siphonal canal. Aperture elongate, approximately half of shell length; outer lip thin, unsculptured. Inner lip whitish, gently recurved. No distinct callus. Anal sinus wide, moderately deep, U-shaped.

Anatomy based on AMS C.571737 and AMS C.571651. Animal semitranslucent whitish. Cephalic tentacles long, narrow, cylindrical, with extremely small eyes situated at their lower outer base. Penis long, narrow. Muscular bulb long, colourless; proboscis long.

Radula ( Fig. 6B) of straight to gently curved hypodermic teeth exceeding 175 µm in length; no ventral barb; dorsal blade sharp, extremely long, approximately half of shaft length; adapical opening elongate, narrow, ranging between a quarter and a half of shaft length. Base broad, with distinct crescentic, slightly excavated shelf more or less perpendicular to orientation of shaft ( Fig. 6B); large dorsal platform extending posteriorly, with numerous, densely arranged folds on inner surface; exterior of base with comparatively fine texture; basal opening large. Ligament broad.

Remarks

This new taxon can be differentiated from other raphitomids by its broad shell with a well-defined carina and a cylindrical whorl periphery with regularly spaced spiral cords and by its hypodermic radular teeth with a long dorsal blade extending approximately half the length of the shaft, and a prominent base forming a crescent-shaped, indented platform.