Thysanoserolis Brandt, 1991

Bruce, Niel, 2009, New genera and species of the marine isopod family Serolidae (Crustacea, Sphaeromatidea) from the southwestern Pacific, ZooKeys 18 (18), pp. 17-76 : 65

Thysanoserolis Brandt, 1991

Thysanoserolis Brandt, 1991: 132 , 146; 1992: 233.– Wägele 1994: 48.

Type species. Serolis completa ( Moreira, 1971) ; original designation ( Brandt 1991).

Species included. The type species, T. completa ( Moreira, 1971) , Brazil; T. elliptica ( Sheppard, 1933) , southwestern Atlantic, from southern Brazil to Straits of Magellan and the Falkland Islands; and T. orbicula sp. n., New Caledonia.

Remarks. The new species described here conforms well with genus with regard to somatic morphology, and the diagnostic uropod morphology. In comparison to the other species the antennule is short, and the antenna far more massive and broad forming a more continual part of the body outline.

In his analysis of the Serolidae Wägele (1994) placed Thysanoserolis and Neoserolis in the same group, a sister group to all other Serolidae , primarily (according to the dendrogram fig. 37) on the basis of the superior margin of the male pereopod 1 being setose, and the basipod and epipod of the maxilliped being fused. Setation of the male pereopod 1 is unknown for the new species.

Brandt (1992) diagnosed the genus as having ‘big eyes’, but eye size varies within the three species, with moderately small, round eyes in T. completa and T. elliptica , and ommatidia absent in the new species, though a reniform–seleniform eye lobe seems to remain. Large eyes in the sense of genera such as Serolis or Acutiserolis are not present in Thysanoserolis .

Pleopod 4, in most serolid genera, has a thin flap that runs along the mesial margin of the exopod, effectively creating a flexible seal to the contained pleotelson. This flap seems to be present in most species of most genera, but is often not figured in illustrations. T. orbicula sp. n. lacks this mesial flange.