Leptochiton parvus, Dell'Angelo, Landau, Van Dingenen & Ceulemans, 2018

Leptochiton parvus View in CoL Dell’Angelo, Landau, Van Dingenen & Ceulemans, 2018

Fig. 27 View FIGURE 27

Leptochiton parvus View in CoL Dell’Angelo, Landau, Van Dingenen & Ceulemans, 2018b, p. 15, fig. 7; Dell’Angelo et al. 2020b, p. 52, tab. 9.

Type material. Holotype: MNHN.F.A67069, intermediate valve, width 2.5 mm, Fig. 27A–D View FIGURE 27 . Paratypes: MNHN. F.A67070, intermediate valve; RGM.1310174, intermediate valve from Beugnon .

Type locality. Saint-Clément-de-la-Place ( Anjou , France) .

Type stage. Miocene (Tortonian).

Material examined. Miocene (Tortonian): France: Saint-Clément-de-la-Place: type material .

Description. Head and tail valves unknown. Intermediate valve broadly rectangular, very elongated (W/L = 3.48), rounded to subcarinate in anterior profile, moderately elevated (H/W = 0.29), anterior and posterior margins almost straight, side margins slightly rounded, apex not developed, lateral areas scarcely differentiated.

Tegmentum rough, space between striae of granules narrow. LA sculptured with seven irregular radial series of widely spaced roundish granules. CA sculptured with 30 longitudinal series of widely spaced roundish granules, of ca. 50 µm of diameter. Each granule with a central megalaesthete and 5–8 micraesthetes irregularly disposed along margin.

Articulamentum without insertion laminae, apophyses triangular.

Remarks. To date, Leptochiton parvus Dell’Angelo, Landau, Van Dingenen & Ceulemans, 2018 is only known upon three small intermediate valves from Saint-Clément-de-la-Place and one from Beugnon, Miocene (Tortonian) of France ( Dell’Angelo et al. 2018b)

Comparisons. Leptochiton parvus is closest to the other species of the Leptochiton cancellatus group, from which it differs by the tegmentum sculpture with a greater number of granular longitudinal striae and smaller interspaces.

Distribution. Upper Miocene: northeastern Atlantic (Tortonian): Ligerian Basin, France: Saint-Clément-de-la-Place, Beugnon ( Dell’Angelo et al. 2018b).