Genus Lycaeopsis Claus, 1879

Lycaeopsis Claus, 1879: 41 –42. Carus 1885: 426. Gerstaecker 1886: 486. Claus 1887: 66. Stebbing 1888: 1458. Spandl 1924: 27. Chevreux & Fage 1925: 417. Spandl 1927: 213. Pirlot 1939: 42. Hurley 1955: 179. Bowman & Gruner 1973: 41. Zeidler 1978: 20. Vinogradov et al. 1982: 358. Shih & Chen 1995: 140. Vinogradov 1999: 1192.

Phorcus Milne Edwards, 1830: 385, 391–392. Milne Edwards 1838: 304. Lucas 1840: 235. Milne Edwards 1840: 79. Dana 1852: 316. Dana 1853: 1000. Bate 1862: 339. Gerstaecker 1886: 485. Claus 1887: 66.

Phorcorrhaphis Stebbing, 1888: 1451 –1452.

Type species

Lycaeopsis themistoides Claus, 1879, by monotypy. Type material could not be found at the ZMB or ZMH and is considered lost. However, Lycaeopsis is a readily recognisable genus.

Type species of synonyms

The type species of Phorcus is P. reynaudii Milne Edwards, 1830 . Type material could not be found at the ANSP or MNHN and is considered lost. Although the description by Milne Edwards (1830) is brief, he mentions the extremely long, thin pereopod 5 that is so characteristic of males of Lycaeopsis . However, Phorcus is preoccupied by a genus of Mollusca (Risso 1826). Thus, Phorcorrhaphis was introduced by Stebbing (1888) as a replacement name. At the time Stebbing did not appreciate that, because of the extreme sexual dimorphism, females were described as species of Lycaeopsis, a genus that has priority.

Sexual dimorphism

This genus probably exhibits more extreme sexual dimorphism than any other hyperiidean. Apart from the structure of the first antennae, the extremely elongated articles of pereopod 5 distinguish males. Other differences are as follows; the body of males is more slender with the pereon being only about half as deep as the pleon, whereas in females they are of similar depth; females lack a mandibular palp; pereopod 6 of males has broader articles, especially the basis and merus; males of at least one species have the endopod of uropod 3 characteristically incised, and the telson is bottled­shaped.

Remarks

Two species are currently recognised in this distinctive genus. While males are readily identifiable, females of the two are more difficult to distinguish.

Although Lycaeopsis is moderately common in tropical and temperate regions, very little is known about its biology.