Dorippe trilobata : Manning 1993

REMARKS ON DORIPPE TRILOBATA MANNING, 1993 AND DORIPPE GLABRA MANNING, 1993

Two Doripp e from Australia described by Manning (1993; see Davie 2002: 156), each known only by its type specimen and thus by a single sex, and never reported since, are problematic. The characters used to distinguish them from other known species are tenuous and mainly concern the more or less marked ornamentation and especially the setation and size of the legs. Previously, only two dorippids were known from Australia: Dorippe quadridens and Paradorippe australiensis. Thanks to photographs of the types of each of these species deposited in the AM, kindly sent to us by Shane Ahyong, some remarks can be provided.

Dorippe trilobata (Manning 1993: 3, 4, fig. 4; cited by Davie 2002: 156), described from Western Autralia (Admiralty Gulf) on the basis of the single holotype, a male 20.5 × 21.1 mm, was considered to be close to D. tenuipes Chen, 1980. Both species were regarded as “different from all other species of Dorippe in having elongate P2 and P3, with the P3 merus six or more times longer than high”, although to a lesser degree in D. tenuipes. In D. trilobata the P2 and P3 (Fig. 15A, B) are longer and thinner than those of most Doripp e (Fig. 10), thus quite similar to those of D. tenuipes (Fig. 9D) but not as thin and elongated as in the latter. The long meri of P2 and P3 of D. trilobata are naked and the dactyli of P2 and especially P3 are enlarged. A characteristic feature of D. trilobata, namely the pleonal somites 2 and 3 with three sharp teeth, is not found in D. tenuipes where there are only low rounded and granular elevations. In D. trilobata, the anterolateral margin is unarmed anterior to epibranchial region and then shows low tubercles, whereas in D. tenuipes it bears numerous denticles. Most significantly, the callosity of D. trilobata is simply hemicircular (Fig. 15A, C, J), contrasting with the complex callosity in the form of a double calcified bulge with a whitish central area in D. tenuipes (Figs 9D; 33G, H).The anterolateral margin of the carapace without spines, tubercles or denticles in front of the epibranchial region is as in D. sinica (Fig. 10C, D); but the three detached spines on the lower margin of the orbit contrast with the cluster in D. sinica and the higher number of teeth there in D. quadridens (Fig. 12B) and may approximate the 3-5 teeth of D. frascone (Fig. 14 A-D). Dorippe trilobata (Fig. 15 A-D) differs from all other species of Dorippe in having a short, triangular and straight-edged pleon, instead of the longer and irregular-edged pleon of other Dorippe; in addition, the three sharp tubercles on pleonal somites 2 and 3 are much more acute than in D. quadridens (Figs 10A; 11B), D. sinica (Figs 10C; 13A) and D. frascone (Fig. 14 A-D). The relatively small size 20.5 × 21.1 mm of the holotype of D. trilobata cannot account for these differences, so until more material is available this species can be considered valid.

Dorippe glabra (see Manning 1993: 1, fig. 1; cited by Davie 2002: 156), from the north of the Northern Territory, known only by an ovigerous female measuring 24.3 × 26.7 mm (deposited in the AM, see Springthorpe & Lowry 1994) and found mixed in a large collection identified as D. quadridens, “could be distinguished on sight from all of the other specimens in that lot by the naked meri of its P2 and P3”, the most significant feature according to Manning (1993: 2, 4). In photographs of the holotype, a male, the meri of the attached left P2, detached left P3 and detached right P3 are naked, but the merus of the detached right P2 (Fig. 15E) is covered with dense setae on the posterior margin. In D. sinica the meri of P2 and P3 are naked or barely pubescent in females (Fig. 10D) and setose in males (Fig. 10C), whereas they are covered with setae in both sexes of D. quadridens (Figs 10A, B; 12A). The P2, P3 of D. glabra (female) are sligthly longer and thinner than in most Dorippe, but not so elongated and thin than those of D. trilobata (Fig. 15A, B), and those of D. tenuipes (Fig. 9D) that are granular. In D. glabra the merus and carpus of the cheliped (Fig. 15E) is covered with dense granules, which eliminates D. frascone with a smooth carpus. In D. glabra the coxa of P3 is flanked by a high hemicircular calcified callosity (Fig. 15E, F, I) similar to that of D. sinica (Figs 9C; 10C, D; 33D, E), quite distinct from the double callosity of D. tenuipes (Figs 9D; 33G, H). A direct comparison between D. glabra and the other Dorippe would be most useful.