Caecum biomaglo Vannozzi 2023, n. sp.
Creators: name: Vannozzi, Angelo
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Caecidae
Caecum
Caecum biomaglo

description: Caecum biomaglo n. sp.
(Figs 2 I-M; 4 C-D; 5 C-D)
urn:lsid:zoobank.org:act: B01458AE-7FEC-4C03-81EA-62424C1DB17D
TYPE MATERIAL. — Holotype. Mayotte • dd (length 2.46 mm, Figs 2 I-J, 4 C and 5 C); Mozambique Channel, S Mayotte, BIOMAGLO Stn DW4820; 13°05’S, 45°06’E; 295-336 m depth; 27.I.2017; MNHN-IM-2000-38700.
Paratypes. Mayotte • 1 dd; same data as for holotype; MNHN-IM-2000-38701 • 1 dd; Mozambique Channel, W Mayotte, BIOMAGLO Stn DW4854; 12°56’S, 44°58’E; 455-465 m depth; 4.II.2017; MNHN-IM-2000-38702.
TYPE LOCALITY. — Indian Ocean, Mozambique Channel, S Mayotte, 13°05’S, 45°06’E, 295-336 m depth.
OTHER MATERIAL EXAMINED. — Îles Éparses • 1 dd cf; Mozambique Channel, Glorieuses, BIOMAGLO Stn DW 4808; 11°30’S, 47°28’E; 219-224 m depth; 25.I.2017; MNHN.
DISTRIBUTION. — Known only from Mayotte. The record from Glorieuses needs confirmation.
ETYMOLOGY. — Derived from the BIOMAGLO Expedition, used as a noun in apposition.
DESCRIPTION
Shell of average size for the genus, tubular, substantially smooth, colourless, semitransparent, somewhat iridescent. Tube cylindrical, tapering near the apex, straight in ventral view. Surface covered by fine growth lines, crossed by a pronounced longitudinal wavy sculpture of fine threads mostly visible in the adapical part. Microsculpture of very fine and regular longitudinal grooves. Macula absent. Aperture somewhat inclined, preceded by a strong varix-like swelling crossed by distinct growth lines, then contracting and ending with a fine reflected lip. Septum low dome shaped without mucro, slightly recessed below the cutting plane. Traces of temporary septum visible at the boundary of the septum with the tube. No traces of periostracum detected. Young stages, protoconch, operculum and soft parts unknown. Holotype: length 2.46 mm, max diam 0.57 mm, min diam 0.41 mm.
REMARKS
At first sight, Caecum biomaglo n. sp. resembles C. succineum due to the smooth shell and the simple low dome shaped septum without mucro. However, the new species is much larger, without distinct annular sculpture and shows a strong swelling before the aperture. The new species recalls Caecum folini Kisch, 1959 and C. bathus Pizzini, Raines & Vannozzi, 2013 from New Caledonia. However, the former shows a slightly more protruding septum, a more conspicuous longitudinal microsculpture and a different shape of the aperture, asymmetric and prolonged after the swelling (Vannozzi 2019d); the latter is more slender, with a subcylindrical tube gradually expanding toward the bell-shaped aperture (Pizzini et al. 2013).
The paratype in Fig. 2 K-L is relatively small and shows no longitudinal sculpture, but all other characters are consistent and it certainly belongs to the new species.
description: Published as part of Vannozzi, Angelo, 2023, The Caecidae from BIOMAGLO Expedition in the Mayotte-Glorieuses area (Mollusca, Gastropoda), pp. 421-434 in Zoosystema 45 (12) on page 426, DOI: 10.5252/zoosystema2023v45a12, http://zenodo.org/record/8177458