Pareuthria Strebel 1905

Genus Pareuthria Strebel, 1905

Type species. Fusus plumbeus Philippi, 1844 (= Pareuthria fuscata (Bruguière, 1789)) by subsequent designation of Tomlin (1932).

The characteristic fusiform shell of Pareuthria has the posterior angle of the aperture usually slightly acute, with a pronounced subsutural ramp giving the somewhat expanded shape to the apertural lip. Sometimes this character is only visible in mature specimens.

This genus has a mostly Magellanic distribution; however, one species extends the range to New Zealand. Harasewych & Kantor (2004) reported with doubt the presence of circum-Antarctic representatives in Pareuthria. Later, Kantor & Harasewych (2013) in a revision of the genus Falsimohnia, where some former species of Pareuthria are now included (i.e. P. innocens Smith, 1907 and P. hoshiaii Numanami, 1996), proposed that those species ranging outside the Antarctic Convergence should be regarded as a different genus other than Pareuthria. There are several important differences in the radula to justify placing the Antarctic representatives in genera different from Pareuthria. Euthria chlorotica Martens, 1878 from Kerguelen Is. was never illustrated by the author. Watson (1886: 209, pl. 13, fig. 8) figured one specimen from about the same locality. According to Martens, it has a tricuspid rachidian with the central cusp longer, and lateral teeth with two strong inwardly-curved cusps of which the outer is longer but narrower. This was mentioned by Thiele (1912: 244) to include E. chlorotica in Pareuthria. The description of this radula fits better in Falsimohnia Powell, 1951 than in Pareuthria where the three rachidian cusps are nearly of the same size. Pareuthria plicatula Thiele, 1912 and P. turriformis Egorova, 1982 were discussed by Kantor and Harasewych (2013) raising some doubts about their inclusion in this genus. Powell (1960: 148) also listed in Pareuthria, Euthria valdiviae Thiele, 1925 and Fusus (Sipho) regulus Watson, 1882 (the latter also in Probuccinum), both known by the shell only, and from Kerguelen Is. Material from Ross Sea (USNM 898064) assigned to E. cf. valdiviae by Dell (1990: 170) showed a radula with a tricuspid rachidian and lateral teeth with four cusps of the same size, which clearly points to a different genus than Pareuthria. In addition, this author reported some similarity of these specimens with “ Fusus ” regulus. Aldea & Troncoso (2010: 121 as P. regulus) and Engl (2012: 149 as Pareuthria sp.) illustrated material assigned to this species. However, no soft parts of “ Fusus ” regulus are known so its generic assignation remains uncertain.