Caecum biomaglo, Vannozzi, 2023

Vannozzi, Angelo, 2023, The Caecidae from BIOMAGLO Expedition in the Mayotte-Glorieuses area (Mollusca, Gastropoda), Zoosystema 45 (12), pp. 421-434 : 426

publication ID	https://doi.org/ 10.5252/zoosystema2023v45a12
publication LSID	lsid:zoobank.org:pub:5EB87A24-068B-40F3-B76B-79E4F48C478A
DOI	https://doi.org/10.5281/zenodo.8183522
persistent identifier	https://treatment.plazi.org/id/B01458AE-7FEC-4C03-81EA-62424C1DB17D
taxon LSID	lsid:zoobank.org:act:B01458AE-7FEC-4C03-81EA-62424C1DB17D
treatment provided by	Felipe
scientific name	Caecum biomaglo
status	sp. nov.

Treatment

Caecum biomaglo View in CoL n. sp.

( Figs 2 View FIG I-M; 4 View FIG C-D; 5 View FIG C-D)

urn:lsid:zoobank.org:act:B01458AE-7FEC-4C03-81EA-62424C1DB17D

TYPE MATERIAL. — Holotype. Mayotte • dd (length 2.46 mm, Figs 2 View FIG I-J, 4 View FIG C and 5 View FIG 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 . GoogleMaps

Paratypes. Mayotte • 1 dd; same data as for holotype; MNHN-IM-2000-38701 GoogleMaps • 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 GoogleMaps .

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 GoogleMaps .

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 View FIG K-L is relatively small and shows no longitudinal sculpture, but all other characters are consistent and it certainly belongs to the new species.