Lepidochitona baluki Macioszcsyk, 1988

Lepidochitona baluki Macioszcsyk, 1988

Fig. 124 View FIGURE 124

Lepidochitona baluki Macioszcsyk, 1988, p. 53 , pl. 2, fig. 4, pl. 3, figs 10–12; Schwabe 2005, p. 90; Dell’Angelo et al. 2012, p.

63; Dell’Angelo et al. 2016, p. 98, tab. 5; Dell’Angelo et al. 2018b, p. 52; Dell’Angelo et al. 2020b, p. 53, tab 9. Lepidochitona sp. Macioszcsyk, 1988, p. 53, fig. 4, pl. 2, fig. 5; Dulai 2005, p. 36, pl. 2, figs 7–9.

Type material. Holotype: MZ VIII Ma-65, head valve ( Fig. 124A View FIGURE 124 ).

Type locality. Węglinek ( Poland) .

Type stage. Middle Miocene.

Material examined. Middle Miocene: Eastern Paratethys : Ukraine: Varovtsi: 3 valves ( BD 945 , Figs 124J–L View FIGURE 124 ), Velyka Levada: 2 valves ( BD 946 , Figs 124D–I View FIGURE 124 ). Maximum width of the valves: 1.3 / 2.6 / 2 mm .

Description. Head valve semicircular, posterior margin widely V-shaped. Intermediate valves broadly rectangular (W/L = 2.40–2.75), moderately elevated (H/W = 0.33–0.40), carinate in anterior profile, anterior margin almost straight to slightly convex, side margins rounded, posterior margin almost straight, with well pronounced apex, lateral areas slightly raised. Tail valve semicircular (W/L = 1.78), mucro subcentral, antemucronal slope slightly convex, postmucronal slope slightly convex.

Tegmentum uniformly covered with coarse granules of irregular shape, randomly arranged and distinctly separated, which appear radially oriented in HV and PMA, 60–80 µm long in CA, each granule with a central megalaesthete, and up to 6–7 micraesthetes irregularly distributed.

Articulamentum with apophyses wide, triangular, slit formula 8 / 1 / 8–11, teeth slightly roughened on outside, eaves spongy.

Remarks. Lepidochitona baluki Macioszcsyk, 1988 was described upon four valves (1 head, 2 intermediate and 1 tail) of small size (maximum width 1.5 mm) from Węglinek ( Poland) ( Figs 124A–C View FIGURE 124 ) and has never been found after. We attribute to Lepidochitona baluki two valves from Velyka Levada and 3 from Varovtsi, which have a tegmentum covered with coarse oval granules, and a similar shape.

Macioszcsyk (1988) described also a single tail valve, considerably arched from Węglin as Lepidochitona sp. This valve is closest to L. baluki , in the tegmentum’s sculpture, it is greater (width 2.7 mm vs. 1.4 in L. baluki ), and differs mainly for the number of slits, 11 vs. 8 in L. baluki . We consider for the moment Lepidochitona sp. falling within the variability of L. baluki , pending the availability of further material that could confirm or not its specific attribution. The two intermediate valves from Bánd ( Hungary), described by Dulai (2005) as Lepidochitona sp. , could be attributable to L. baluki .

Comparisons. The sculpture of the tegmentum is coarser than the three other species of Lepidochitona known from the Paratethys. See Tab. 20 for more comparison with the other Lepidochitona spp . from the Paratethys considered in the present study.

Distribution. Middle Miocene. Central Paratethys (Langhian-Serravallian): Poland: Węglin, Węglinek ( Macioszczyk 1988), Hungary: Bánd ( Dulai 2005; this study); Eastern Paratehys: Ukraine: Varovtsi, Velyka Levada (this study).