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 (2023-07-24 11:53:16, last updated 2024-11-26 22:09:11)
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.

References

PIZZINI M., RAINES B. & VANNOZZI A. 2013. - The family Caecidae in the South-West Pacific (Gastropoda: Rissooidea). Bollettino Malacologico 49 (suppl. 10): 1 - 78. https: // www. biodiversitylibrary. org / part / 291987

VANNOZZI A. 2019 d. - Rediscovery of Caecum folini Kisch, 1959 (Gastropoda: Caecidae). Basteria 83 (4 - 6): 166 - 168. https: // natuurtijdschriften. nl / pub / 1001511 / BAST 2019083004010. pdf

Figures

FIG. 2. — Side and ventral views of Caecum Fleming, 1813 species from BIOMAGLO Expedition: A-C, C. sepimentum de Folin, 1868 from Stn DW4848; A, B, specimens with preserved colour pattern; C, juv.; D, C. succineum de Folin, 1880 from Stn DW4854; E-H, C. iricolor n. sp.; E, F, holotype MNHN- IM-2000-38696, length 2.33 mm; G, H, paratype MNHN-IM-2000-38697 from type locality; I-M, C. biomaglo n. sp.; I, J, holotype MNHN-IM-2000-38700, length 2.46 mm; K, L, paratype MNHN-IM-2000-38701 from type locality; M, paratype from Stn DW4854 MNHN-IM-2000-38702; N, Caecum sp. from Stn DW4847, length 2.4 mm. Scale bar: 1 mm.

FIG. 4. — Detail of the septum (right side) of Caecum Fleming, 1813 species: A, B, C. iricolor n. sp.; A, holotype MNHN-IM-2000-38696; B, paratype MNHN- IM-2000-38697; C, D, C. biomaglo n. sp.; C, holotype MNHN-IM-2000-38700; D, paratype MNHN-IM-2000-38701; E, C. sp. from Stn DW4847; F, C. hyalinum Vannozzi, 2022 from Stn DW4847. Scale bar: 100 µm.

FIG. 5. — Detail of the aperture (right side) of Caecum Fleming, 1813 species: A, B, C. iricolor n. sp.; A, holotype MNHN-IM-2000-38696; B, paratype MNHN- IM-2000-38697; C, C. biomaglo n. sp., holotype MNHN-IM-2000-38700; D, Caecum sp. from Stn DW4847. Scale bar: 100 µm.