Tridentella Richardson, 1905

Bruce, Niel L. & Svavarsson, Jörundur, 2018, Three new species of Tridentella Richardson, 1905 (Isopoda: Cymothoida: Tridentellidae) from New Caledonia, Zootaxa 4399 (1), pp. 101-118 : 102

Tridentella Richardson, 1905

Restricted synonymy.— Tridentella Brandt & Poore 2001: 200 .— Bruce 2008: 43.

Type species: Cirolana virginiana Richardson, 1900 ; by monotypy. Richardson (1900) gave no type locality and no figures, just two lines of ambiguous text; later Richardson (1901) cited the type locality for the named type species as Chesapeake Bay, gave one figure of the pleon and pleotelson, and mentioned two syntypes (USNM 6350). Richardson (1905, p. 162, 163) expanded the description to include additional figures, but it is not clear which specimens these figures were taken from as her material at hand was of two specimens from off the Santa Barbara Islands, California. The Californian specimens have subsequently been identified as Tridentella quinicornis Delaney & Brusca, 1985 .

Remarks: With the increasing number of species in the genus it is now possible to make some comments on the relationships between the species based simply on shared characters (see list below). One group of species is characterized by having a generally ornate dorsal body surface, sometimes highly so; some of these species have the apparently unique character within the Cymothooidea of large, overlapping scale-like serrations on the lateral margin of the pleotelson; most species in this group have longitudinal carinae on the pleotelson dorsal surface.

Species that lack ornamentation include two separate pairs of species—one pair, geographically widely separated, is characterized by the pleotelson apex being deeply excavate, the species being T. recava Bowman, 1986 (off New York, USA) and T. tanimbar Bruce, 2008 (Banda Sea, Indonesia). The species pair T. memikat Bruce, 2008 and T. magna sp. nov. has in common their large size (c. 3 cm), antennula and antenna morphology and general somatic morphology.

The remaining species differ in aspects of pleotelson and uropod characters as well as setation of the pereopods, but otherwise do not show any obvious uniting characteristics.