Potamonautes minor Bott, 1955

Meyer, Kirstin S. & Cumberlidge, Neil, 2011, A revision of the freshwater crabs (Crustacea: Decapoda: Brachyura: Potamonautidae) of the Lake Kivu drainage basin in Central and East Africa, Zootaxa 3011, pp. 45-58 : 49-51

Potamonautes minor Bott, 1955

( Fig. 3–5 , Table 1 , 2)

Potamonautes (Lobopotamonautes) perparvus minor Bott 1955: 284 , fig. 49 a, b; plate 21, fig. 2a–d. Potamonautes perparvus minor— Ng et al. 2008: 171.

Potamonautes minor— Cumberlidge et al. 2009: appendix item 931.

Type material examined. DR CONGO: Matale, Upper Congo near to Lake Kivu, adult male (CW 20.4, CL 14.4, CH 7.7, FW 5.7), adult male (CW 16.9, CL 12.8, CH 6.5, FW 4.9), adult male (CW 16.0, CL 12.0, CH 6.6, FW 4.8), adult female (CW 18.5, CL 14.4, CH 6.7, FW 5.7) (F. Hautmann) ( SMF 2427); Upper Congo near to Lake Kivu, Tschiwia stream and Mukoba, Kahuzi-Biega National Park, 2250 m asl, adult male (CW 19.3, CL 14.3, CH 6.8, FW 5.5) (R. Laurent) ( SMF 2426); Mongbwalu, 1951 (Schietz) ( SMF 2408).

Diagnosis. Carapace highly arched ( CH /FW1.37), surface smooth, postfrontal crest faint, complete; exorbital tooth reduced to small granule, epibranchial tooth absent, anterolateral margin smooth; horizontal sulcus on carapace sidewall lacking granules; ischium of third maxilliped with faint vertical sulcus; sternal sulcus s2/s3 deep; s3/ s4 deep at edges, faint in middle, meeting top of sternoabdominal cavity; first carpal tooth on carpus of cheliped distinct, pointed; second carpal tooth smaller, pointed, followed by a large granule; distal meral tooth of P1 merus very small, pointed; fixed finger of propodus of major cheliped lined by small, rounded teeth, two teeth prominent; dactylus of major cheliped lined by small, rounded teeth, single prominent tooth about half-way along, dactylus straight, fingers enclosing long narrow interspace; terminal article of G1 significantly widened in middle, tapering to slim, upturned tip, lateral fold higher than medial fold, groove on terminal article visible on dorsal side; dorsal membrane narrow, margins equal in width ( Fig. 3 , 4 ).

Size. A small species with an adult size range of CW 21–22 mm.

Type locality. DR Congo, Matale, Upper Congo, adjacent to Lake Kivu ( Fig. 5 ).

Conservation status. Potamonautes minor is listed as “least concern” ( IUCN 2003; Cumberlidge et al. 2009) because there is no evidence that there is a decline in the extent and quality of its habitat and there are no long-term threats to its habitat from disturbance and pollution ( Cumberlidge 2008b).

Distribution. Potamonautes minor is found in the tributaries of the Congo River and Lake Kivu drainage basins. This species has been collected from Kahuzi-Biega National Park and Mongbwalu in the DR Congo ( Fig 5 ; Table 2).

Remarks. Bott (1955) considered P. m i no r to be a subspecies of P. perparvus . However, Potamonautes minor is distinguished from P. perparvus by the terminal article of G1: in P. m i n o r it is widened in the middle and the lateral fold is higher than the medial fold, while in P. perparvus the terminal article is only slightly widened in the middle and the medial fold is higher than the lateral fold ( Rathbun 1921, Table 1 ).

Figures

FIGURE 3. Potamonautes minor. A, dorsal view; B, frontal view; C, sternal view. Adult male paratype (SMF 2427), CW 20.4 mm.

FIGURE 4. Potamonautes minor. A, G 1, ventral view; B, G 1, dorsal view; C, G 2; D, detail of G 1 tip, ventral view; E, detail of G 1 tip, dorsal view. Adult male paratype (SMF 2427), length of G 1 terminal article measured along the mid-line of the dorsal face from tip to dorsal membrane = 1.4 mm.

FIGURE 5. Potamonautes minor distribution. = type locality, = other localities. Scale bar = 249 km. Localities are shown for material examined in this study and from Bott (1955).