Family UROTHOIDAE Bousfield, 1978

Haustoriidae (in part) – Chevreux and Fage 1925: 91, figs 90–95; Gurjanova 1951: 328, figs 210–212; Lincoln 1979: 312, figs 154–156; Bellan-Santini 1989: 365, figs 257–264.

Urothoidae (in part) Bousfield 1978: 356.

Urothoidae Barnard and Karaman 1991: 726 .

Diagnosis (modified from Barnard and Karaman 1991).

Head short, rostrum weak, anteroventral angle well developed and projected ventrally. Antenna 1, peduncle with articles elongated, geniculate between articles 2 and 3, flagellum short. Antenna 2 strongly sexually dimorphic in most taxa; article 4 weakly expanded, stout setae absent or in setal rows; article 5 slightly shorter and more slender than article 4; flagellum variable in length, commonly short in females and elongated in males. Upper lip dominant in size, epistome slightly distinct. Mandible short and stout, incisors smooth or weakly spinose; accessory setal row weakly developed or absent; palp 3-articulate, article 3 apically rounded. Lower lip, outer lobes well developed. Maxilla 1, inner plate with fewer than six setae; palp 2-articulate. Maxilla 2 inner and outer plates subequal in length. Maxilliped palp 4-articulate, article 2 expanded or nasiform, article 4 unguiform to clavate, commonly setose, apical nail weakly developed. Gills at pereonite 2 to 6, oostegites slender. Gnathopods 1 and 2 slender, similar to each other, ischium short, carpus elongate. Pereopods 3–5 carpus well developed. Pereopods 6–7 similar or developed in phoxocephalid form, with pereopod 7 shorter than pereopod 6, with basis posteriorly expanded. Epimeral plate 3 dominant in size. Uropod 3 peduncle short, flat and expanded; outer ramus 2-articulate, dominant in size. Telson cleft.

Type genus

Urothoe Dana, 1852

Composition

Carangolia Barnard, 1961; Carangolioides gen. nov.; Coronaurothoe gen. nov.; Cunicus Griffiths, 1974; Urothoe Dana, 1852; and Urothoides Stebbing, 1891 .

Removed genera

Pseudurothoe Ledoyer, 1986 and Urothopsis Ledoyer, 1967 are transferred here to Phoxocephalopsidae Barnard and Clark, 1982 .

Remarks

Until now, the family Urothoidae included three monotypic genera: Cunicus, Pseudurothoe and Urothopsis; the last two genera are now removed to Phoxocephalopsidae . Carangolia comprises four described species, Urothoides 10 species and Urothoe, which is the most speciose, 44 species. Most taxonomic studies dedicated to this group in the past commonly have neither illustrations nor descriptions of mouthparts. In this study, we detail these structures, which have become essential for the separation of the species, and which have been used to establish the two new genera described herein. Another important aspect of urothoid taxonomy is that only a small number of structures have been illustrated and often the descriptions are short or poorly detailed, as in Chevreux and Fage (1925), Gurjanova (1951), Lincoln (1979) and Bellan-Santini (1989), making it difficult to recognize the species. The biggest taxonomic problem in the family Urothoidae involves the genus Urothoe, because it has a large number of species and some variation in the character states. In the original description of Dana (1852) only a few features were used, including: gnathopods 1 and 2 slender, subchelate, and similar; antenna 1 shorter than antenna 2; maxillipeds long and slender, with inner plate small; uropod 3 rami foliaceous; and telson deeply cleft. Only the uropod 3 with foliaceous rami is an exclusive feature of the genus, which makes it a weakly defined group. Many species displaying features described above were grouped into Urothoe, resulting in a taxon with wide morphological variation. These facts suggest that Urothoe might be, actually, a non-monophyletic group. Currently, Urothoe is in great need of an extensive revision, and a more restricted diagnosis for it must be established. Still, in this work it has been possible to establish two new genera supported by clear and well-defined characters. The diagnostic characters of the genera included in Urothoidae are presented in Table 1.