Lucilina perligera Thiele, 1909

Dell’Angelo, Bruno, Landau, Bernard M., Sosso, Maurizio & Taviani, Marco, 2020, Late Pleistocene Red Sea Mollusca: 1. Polyplacophora, Zootaxa 4772 (3), pp. 401-449 : 417-418

Lucilina perligera Thiele, 1909

( Fig. 10 )

Lucilina perligera Thiele 1909, p. 97 , pl. 10, figs 51–52; Kilias 1995, p. 167; Dell’Angelo et al. 2010a, p. 15, figs 5A–B; Blatterer 2019, p. 52, pl. 4, fig. 9 a–k.

Tonicia perligera ; Leloup 1960, p. 39, fig. 4; Leloup 1980, p. 12; Dekker & Orlin 2000, p. 7; Slieker 2000, p. 50, pl. 13, fig. 27.

Tonicia (Lucilina) perligera ; Strack 1993, p. 20, pl. 4, figs 7–9; Kaas & Van Belle 1998, p. 142; Anseeuw & Terryn 2004, p. 15, figs 24–31, 48–49; Kaas et al. 2006, p. 319, fig. 131, map 18.

Non Tonicia perligera ; Ferreira 1983, p. 274 (= Lucilina sueziensis , fide Strack 1993, p. 21).

Type material. Holotype ZMHU Moll. 102059.

Type locality. Red Sea .

Material examined. Egypt, Hurghada : St. 13: 1 head valve, width 4 mm ( Figs 10 A–C) ( MZB 50536); St. 14 bis: 1 head valve, width 3 mm, Fig. 10D ( MZB 50537) .

Recent material examined. Israel, Eilat (P448A): 7 valves (3 head, 2 intermediate and 2 tail), Figs 10 E–I ( BD 204; MZB 50538).

Description. Head valve semicircular, posterior margin almost straight, front slope slightly convex, tegmentum sculptured with quincuncially dispersed, large, clearly separated, highly elevated, roundish granules, diameter ca 120–160 µm, ocelli minute, black, randomly dispersed.

Articulamentum worn and incomplete.

Remarks. The present material most resembles Lucilina perligera Thiele, 1909 . A detailed description of that species, characterised by the tegmentum sculptured with large, widely separated granules, was given by Kaas et al. (2006). Two head valves at hand have the same type of sculpture, but with the granules more widely spaced ( Figs 10A, D ). We report a Recent head valve of Lucilina perligera from the Gulf of Aqaba ( Figs 10 E–F), with the denser sculpture of close-set granules more typical for this species. The granules have the same roundish/oval shape and are of comparable dimensions, diameter ca 120–160 µm in the fossil valve ( Fig.10B ), ca 140–180 µm in the living valve ( Fig. 10F ). The diameter of the granules is variable, Strack (1993: 21) reported a diameter of 130–150 µm in the holotype, and up to 260 µm in loose valves studied; Anseeuw & Terryn (2004: 16) gave a diameter up to 280 µm. The only difference between the head valves of living and fossil specimens seems to be the smaller, wider-spaced granules on the tegmentum in the fossil ones. We also illustrate, for completeness and for comparison with the other species of Lucilina described here, an intermediate and a tail valve of L. perligera from the Gulf of Aqaba ( Figs 10 G–I).

Lucilina perligera resembles L. sueziensis (see above) in many respects, but can be easily differentiated by the sculpture of the tegmentum, which has large, widely spaced granules.

This is the first report of this species as a fossil.

Distribution. Late Pleistocene: Egypt, Hurghada (this study). Present-day: northern Red Sea and Maldive Islands ( Dell’Angelo et al. 2010a; Kaas et al. 2006; Blatterer 2019).

Figures

FIGURE 10. Lucilina perligera Thiele, 1909. A–D. Egypt, Hurghada, Late Pleistocene (last interglacial MIS5e). A–C. MZB 50536, head valve (St. 13), width 4 mm, dorsal view, detail of tegmentum surface and lateral view. D. MZB 50537, head valve (St. 14bis), width 3 mm, dorsal view. E–I. Israel, Gulf of Aqaba, present-day (P448A). E–F. MZB 50538a, head valve, width 5 mm, dorsal view and detail of tegmentum surface. G–H. MZB 50538b, intermediate valve, width 6 mm, dorsal view and detail of tegmentum surface. I. MZB 50538c, tail valve, width 3,5 mm, dorsal view. Scale bars: 100 µm (B, F, H).