Hypermastus sp.

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

Hypermastus sp. Figure 15

New records.

Israel • 4 shs; off Tel Aviv Marina; 32.0871°N, 34.7635°E; depth 7 m; 8 Nov. 2018; rocky reef; suction sampler; HELM project (sample S67_3F); size: H 1.9 mm, L 0.5 mm (illustrated shell).

Remarks.

This slender eulimid is characterized by a constriction at the transition between the protoconch and the teleoconch (Figure 15A, B, F ). This feature distinguishes it at once from any native Mediterranean species. The protoconch is ~ 2.5 whorls, apparently without any ornamentation. The teleoconch is very slender, made of 6 translucent-white whorls, with flat sides, inconspicuous suture; the lip profile is arched. These characters fit the genus Hypermastus Pilsbry, 1899 to which we tentatively assign the species ( Warén 1991b). We were not able to assign it to any Indo-Pacific species, but the family is among the most diverse and least known in that province ( Bouchet et al. 2002), thus it could be another still undescribed species recently introduced into the Mediterranean Sea.

Figures

Figure 15. Hypermastus sp., Tel Aviv, Israel, HELM project (sample S 67 _ 3 F): front (A, B), side (C, D) and back (E) views, apex with optical microscope (F) and SEM (G) showing the protoconch-teleoconch transition (the shell had a different orientation in images F and G). The arrow marks the constriction between protoconch and teleoconch that is a diagnostic character for this species. Scale bars: 0.5 mm (A-E); 0.2 mm (F, G).