Platythelphusa echinata Capart, 1952

Reed, Sadie K. & Cumberlidge, Neil, 2006, Brachyura: Potamoidea: Potamonautidae, Platythelphusidae, Deckeniidae (), Zootaxa 1262 (1), pp. 1-139 : 1-139

20. Platythelphusa echinata Capart, 1952 (Fig. 192, plate XX)

Platythelphusa echinata Capart, 1952: 58–60 , figs. 7h, i, 9; Cumberlidge, 1999: 277; Cumberlidge et al., 1999: 1509–1510, fig. 6, 7 f, j–k, 8f, q, r, 9 f, 10 t –w; Marijnissen et al., 2004: 528–530, Tables 1, 2.

Potamonautes (Platythelphusa) echinata — Coulter, 1991: 253–255, tables 9.XX, 9.XXI.

Type material examined: Lake Tanganyika , Station 88, 2 adult male paratypes (largest cw 15 mm), donated by A. Capart, ( BMNH 1952.10.23.23–27) .

Additional material examined: TANZANIA: See Cumberlidge et al. (1999).

Diagnosis. Carapace subhexagonal, very flat (ch/fw 0.76). Frontal margin granular, small blunt tooth at each external corner. Exorbital tooth small, pointed; epibranchial tooth large, pointed. Three teeth decreasing in size posteriorly on anterolateral margin behind the epibranchial tooth, anterolateral margin continuous with posterolateral margin. Suborbital margin lined by small granules, no small tooth at medial end. Lateral inferior margin of merus of cheliped smooth; large pointed tooth, several medium­sized teeth on medial inferior margin; superior margin with row of small granules. Inner margin of carpus of cheliped with two large subequal teeth close together, articular tooth (at point of articulation with propodus) large, pointed; outer margin of carpus with row of small granules. Coxa of p2–p5 with sharp spine on inferior medial margin. Merus of p5 as long as fw, sharp distal tooth on superior margin. Propodus of p4 long, propodus of p5 short, broad, posterior margin of propodus of p2–p5 lined by large pointed teeth. Dactyli of p2–p5 curved, rows of spines very long. Terminal article of gonopod 1 directed sharply outward at 90° angle to the vertical, slim, cone­shaped, tapering to pointed tip.

Description. See Cumberlidge et al. (1999) and Capart (1952).

Size. The adult size range is from cw 16 to cw 21 mm.

Distribution. Endemic to Lake Tanganyika: Burundi. For more localities see Capart (1952). This species is found in waters from 5–30 m deep, where the lake­bed is sandy or rocky, and it is sometimes found in sandy or muddy parts of the lake inside empty Neothauma sp. shells.

Remarks. The two rows of short spines on the inferior border of the merus and propodus of p2–p5 distinguish P. echinata from all other species in this genus. In addition, the large spine on the coxae of p1–p5 of P. echinata distinguishes it from all other species in the genus, except P. tuberculata . This species was redescribed by Cumberlidge et al. (1999), who provided details of its identification, distribution and ecology. The terminal article of gonopod 1 is directed outward at a 45° angle to the vertical, rather than at a 90° angle as stated in Cumberlidge et al. (1999).

Natural history and conservation status. The conservation status of P. echinata is categorized as least concern (LC) ( Table 4) because it has a range of occurrence and an area of occupancy in excess of the thresholds for vulnerable (VU) ( IUCN 2004). Its population is estimated to be stable based on indirect measures such as the fact that a lot of material has been collected recently from more than one locality (S. Marijnissen, pers comm.).