Ischnochiton renardi, Dell'Angelo, Lesport, Cluzaud & Sosso, 2018

Ischnochiton renardi View in CoL Dell’Angelo, Lesport, Cluzaud & Sosso, 2018

Fig. 68 View FIGURE 68

Ischnochiton renardi View in CoL Dell’Angelo, Lesport, Cluzaud & Sosso, 2018a, p. 24, figs 5M–R.

Type material. Holotype: MHNBx 2017.8.1, an intermediate valve, width 6.4 mm ( Figs 68A–C View FIGURE 68 ). Paratypes: MZB 32135, an intermediate valve; MHNBx 2017.8.2, an intermediate valve ( Fig. 68D View FIGURE 68 ).

Type locality. Moulin-Pochas , Ligerian Basin ( France) .

Type stage. Upper Miocene (Messinian?) .

Material examined. Upper Miocene: France (Messinian?): Moulin-Pochas (Amberre): type material plus 4 valves (PR), maximum width of the valves: 7.5 mm .

Description. Head and tail valves unknown.Intermediate valves broadly rectangular, carinated in anterior profile, moderately elevated (H/W = 0.40), posterior margin almost straight, side margins rounded, apex inconspicuous, lateral areas slightly raised.

CA sculptured with 52–56 longitudinal granulose riblets, tending to be more irregular towards side margins, with scarce evidence of interstices, and cover also JA. LA sculptured with 6–7 radial granulose riblets, larger than the longitudinal ones in CA, tending to split near side margins, with evidence of growth lines and with granules tending to coalesce near the anterior margin.

Articulamentum with apophyses wide, one slit for each side.

Remarks. Ischnochiton renardi Dell’Angelo, Lesport, Cluzaud & Sosso, 2018 is only know from the original material, based on 7 intermediate valves from the upper Miocene of France, sometimes incomplete and poorly preserved, especially the characters of the articulamentum are scarcely visible

Comparisons. Ischnochiton renardi at a first look resembles I. zbyi Dell’Angelo & Silva, 2003, with whom it shares the carinated profile, but differs by the different sculpture, longitudinal sulci with interstices almost equal or slightly narrower than sulci and smooth jugum in I. zbyi , granulose riblets with scarce evidence of interstices, and covering also the jugal area in I. renardi , and the greatest elevation (H/W = 0.40 vs. 0.26–0.36 in I. zbyi ), and moreover the different geographic and stratigraphic range, upper Miocene of Ligerian Basin ( France) for I. renardi , vs. Pliocene of Mondego Basin ( Portugal) for I. zbyi .

Distribution. Upper Miocene: northeastern Atlantic: Ligerian Basin, France: Moulin Pochas ( Dell’Angelo et al. 2018a).