Leptochiton corticellii, Dell’Angelo & Sosso & Taviani, 2025

Leptochiton corticellii sp. nov.

Fig. 14 View FIGURE 14

Type material. Holotype: MSNG 62628 View Materials , tail valve, width 1.3 mm ( Figs 14A–C View FIGURE 14 ) . Paratype: MSNG 62629 View Materials , tail valve, width 1 mm ( Figs 14D–H View FIGURE 14 ) .

Type locality. Archi ( Calabria, Italy) .

Type stage. Lower Pleistocene (a bathyal paleoenvironment, 500 to 1000 m paleodepth: Di Geronimo et al. 1997).

Etymology. The species is dedicated to Franco Corticelli (IMM-CNR Bologna) as a recognition of his valuable and skilful support to produce most of the S.E.M. images of this study.

Material examined. Italy: Archi : type material .

Diagnosis. Tail valve semicircular, mucro in slighty posterior position. Tegmentum rough, sculptured with elevated granules, irregularly arranged, with 2–3 stems in apical part, roundish in AMA, flattened oval, almost rectangular, in PMA, each granule with three aesthetes almost aligned. Articulamentum without insertion laminae, apophyses small, triangular.

Description. Head and intermediate valves unknown. Tail valve semicircular, anterior margin straight, mucro in slightly posterior position, not prominent, antemucronal slope slightly convex, postmucronal slope slightly concave.

Tegmentum rough, with some isolated stem irregularly present, sculptured with elevated granules, irregularly arranged, with 2–3 stems in apical part, roundish in AMA (diameter up to 40 µm), flattened oval, almost rectangular, in PMA (length up to 40 µm), showing a more or less concentric arrangement. Stems give striated aspect to the tegmentum, and these are interrupted by granules. Each granule with three aesthetes almost aligned, one central megalaesthete and two micraesthetes on side.

Articulamentum without insertion laminae, apophyses small, triangular, widely separated by a large jugal sinus.

Remarks. Although only two tail valves are available in the material studied, the good state of conservation and the particular sculpture of the tegmentum, different from that of other known living and fossil species, allow us to describe it as a new species.

Comparisons. Leptochiton corticellii sp. nov. is very similar to L. pepezamorai Carmona Zalvide, Urgorri & García, 2004 , a living species known from Galicia (NW Spain) and from the Mediterranean area (Tuscan Archipelago, S. Lucia Bank: Dell’Angelo et al. 2009), a species not treated here because not known as a fossil, from which it differs mainly by the different arrangement of granules on AMA, randomly in Leptochiton corticellii sp. nov., vs. in longitudinal series in L. pepezamorai .

Distribution. Lower Pleistocene: central Mediterranean, S. Italy: Archi (this study).