Parthenina typica (Laseron, 1959)

Albano, Paolo G., Steger, Jan, Bakker, Piet A. J., Bogi, Cesare, Bosnjak, Marija, Guy-Haim, Tamar, Huseyinoglu, Mehmet Fatih, LaFollette, Patrick I., Lubinevsky, Hadas, Mulas, Martina, Stockinger, Martina, Azzarone, Michele & Sabelli, Bruno, 2021, Numerous new records of tropical non-indigenous species in the Eastern Mediterranean highlight the challenges of their recognition and identification, ZooKeys 1010, pp. 1-95 : 1

Parthenina typica (Laseron, 1959) Figure 27

New records.

Israel • 2 spcms; Palmachim; 31.9737°N, 34.6767°E; depth 35.4 m; 2 Sep. 2015; soft substrate; box-corer; Shafdan project (sample 29(C)) • 4 spcms; Palmachim; 31.9685°N, 34.6732°E; depth 35.6 m; 2 Sep. 2015; soft substrate; box-corer; Shafdan project (sample 26(B)); size: H 2.0 mm, W 0.8 mm (illustrated specimen) • 1 sh; north of Atlit; 32.7433°N, 34.9067°E; depth 40 m; 20 Sep. 2016; coarse biogenic sediment in a pool among rocks covered by coralligenous formations; grab; HELM project (sample NG40_2M) • 1 spcm; Ashqelon; 31.7487°N, 34.4960°E; depth 41 m; 18 Sep. 2016; sandy mud; grab; HELM project (sample SG40_1F).

Remarks.

This species is characterized by a straight, conical profile with flat whorls, separated by a deep, canaliculate suture; the abapical part of the whorl is angulated. The sculpture consists of straight axial ribs and a prominent suprasutural spiral cord; the base is smooth except for faint continuations of the axial ribs; an internal columellar fold is present and visible inside the aperture when slightly turning the shell to the left side. The protoconch is of type C and in the illustrated specimen it has a diameter of ~ 240 μm, which is slightly smaller than 270-290 μm stated by Peñas and Rolán (2017) for this species.

Parthenina typica (Laseron, 1959) was described from eastern Australia ( Laseron 1959) and subsequently recorded from the Solomon Islands, Fiji and the Philippines at infralittoral to bathyal depths ( Peñas and Rolán 2017). To our knowledge, it has not been reported from the Indian Ocean nor from the Red Sea, however, its absence could well represent an artifact of the limited knowledge of the micromollusk fauna of these regions. Among native species, the conchologically highly variable Parthenina interstincta (J. Adams, 1797) and P. monozona (Brusina, 1869) are most similar, however, they differ by having more rounded whorls and a greater number of axial ribs.

Figures

Figure 27. Parthenina typica (Laseron, 1959), Palmachim, Israel, Shafdan project: front (A, B) and back (C, D) views, apex (E) and apical view of the protoconch (F). Scale bars: 0.4 mm (A-D); 0.1 mm (E, F).