Cyclocaris Stebbing 1888

Genus Cyclocaris Stebbing, 1888

Cyclocaris Stebbing, 1888: 664.— Stebbing, 1906:30.— Barnard, 1969: 338–339.— Barnard & Karaman, 1991: 479.— Lowry & Stoddart, 2011: 58–60.

Type species. Cyclocaris tahitensis Stebbing, 1888, original designation.

Diagnosis. As for the family. Maxilla 1 palp apically strongly tridentate, each tooth crowned with a robust seta. Species composition. Cyclocaris tahitensis Stebbing, 1888; Cyclocaris guilelmi Chevreux, 1899; Cyclocaris lowryi sp. nov.; Cyclocaris franki sp. nov.

Remarks. The Cyclocaridae most closely resemble the Cebocaridae and can be distinguished by the head being only slightly deeper than long; the presence of eyes; the more strongly asymmetric incisors; the setose molar and the simple non-prehensile pereopods (Lowry & Stoddart, 2011). C. guilelmi is unusual in having eyes that cover most of the head and that are not destroyed by fixation and preservation. In the remaining three species eyes fade or disappear completely following preservation as was reported for C. tahitensis (Lowry & Stoddart, 2011). The two new species each possess four irregular and somewhat variable ocular patches; bright red in the case of C. franki sp. nov. (Figure 2). In common with some other lysianassoids, the bright red pigment found in the two new species is highly labile in alcohol (Thurston, 1974; Thurston & Bett, 1993).

Cyclocarids are necrophages to a greater or lesser extent; all species have been caught in baited traps. In common with otherwise unrelated necrophagous lysianassoids such as Alicella, Eurythenes and some members of the Uristidae, Cyclocaris species share a total loss of the triturating surface on the mandibular molar and a shortening of the inner plate of maxilla 2 (De Broyer & Thurston, 1987; Stoddart & Lowry, 2004; Lowry & Stoddart, 2011; unpublished observations). When fully gorged, the hugely extended sternites of the pereon make specimens of Cyclocaris very obvious in trap catches (Figure 3).