19. Altenaeum gibbosum (Thiele, 1912) [Figs 9K–M]

Tellimya gibbosa Thiele, 1912: 230, pl. 18, fig. 12

Material examined. • 4 spms, Stn. 2.

Type locality. Gauss station (Davis Sea) at a depth of 385 m.

Bathymetric distribution. 1–752 m.

Substrate. Soft bottom.

Geographical distribution. ANTARCTICA: Circum-Antarctic. SUBANTARCTICA: -. SCOTIA ARC: South Orkney Islands, South Shetland Islands. SOUTH AMERICA: -.

Remarks. The identification of this species was difficult. Mysella minuscula (Pfeffer, 1886), a species with nomen dubium status in MolluscaBase, which has been observed loosely in some previous studies for King George Island (e.g. Narchi et al. 2002, Passos & Domaneschi 2006), may belong to this species. However, we came to the conclusion that our species belongs to Altenaeum gibbosum . It has a more backward-orientated umbo, which is also somewhat raised. The shape is more ovoid than roundish. The main teeth of the right valve are very short but prominent. Ultimately, however, a certain uncertainty remains in terms of identification. We found a few specimens in the Fildes Strait at a depth of 70 m.

References. Dell (1990), Narchi et al. (2002), Passos & Domaneschi (2006), Aldea & Troncoso (2010a), Huber (2015), Steger et al. (2023).