Telphusa infravallata Hilgendorf, 1898: 12–13 Potamon (Potamonautes) infravallata Rathbun, 1905: 174 Potamon (Potamonautes) usambarae Rathbun, 1933: 257 Chace, 1942: 189 Potamon infravallatus Chace, 1942: 213 Potamonautes (Rotundopotamonautes) infravallatus Bott, 1955: 293–294 Brachyura: Potamoidea: Potamonautidae, Platythelphusidae, Deckeniidae () Reed, Sadie K. Cumberlidge, Neil Zootaxa 2006 2006-07-17 1262 1 1 139 4M4HM (Hilgendorf, 1898) Hilgendorf 1898 [293,864,1524,1550] Malacostraca Potamonautidae Potamonautes Animalia Decapoda 18 Arthropoda species infravallatus      Telphusa infravallata Hilgendorf, 1898: 12–13, fig 2, 2a.    Potamon (Potamonautes) infravallata—  Rathbun, 1905: 174.     Potamon (Potamonautes) usambarae Rathbun, 1933: 257, pl. 6;  Chace, 1942: 189, fig. 2.    Potamon infravallatus—  Chace, 1942: 213.    Potamonautes (Rotundopotamonautes) infravallatus—  Bott, 1955: 293–294, pl. XXV, fig. 2a–d, fig. 57.    Typematerial examined: TANZANIA:  Telphusa infravallata: Usambara Mountains, Buloa, adult male type(cw 23.4, cl 15.4, ch 7.4, fw 6.5 mm) ( ZMB11378);  Potamon(Pot­  amonautes) usambarae: male subadult cotype (cw 22.4, cl 16.8, ch 6.8, fw 6.0 mm); female subadult cotype (cw 12.2, cl 9.5, ch 4.9, fw 3.6 mm), East Usambara Mountains, Amani, xii.1926(A. Loveridge) ( MCZ7680).  Additional material examined:   TANZANIA: East Usambara Mountains, Amani, female (damaged), male (damaged),  8.xii.1926( A. Loveridge) ( USNM 64108);  Amani, East Usambara mountains, 2 males(cws 17.1, 18.2 mm),  1.i.1964( J. N. Raybould) ( NMU TRW1964.03b);  East Usambara Mountains, Amani, 3 males(cw 19.8 to cw 22 mm), adult female (cw 24.1 mm), 2 subadultfemales (cws 19.8, 21.4 mm),  v.1966( J. N. Raybould) ( NMU TRW1966.12a);  West Usambara Mountains, Milinga River, Tewenear Mlalo, adult female (cw 22.8 mm),  18.ii.1967( J. N. Raybould) ( NMU TRW1967.11);  East Usambara Mountains, Amani, 3 juvenilemales (cw 10.9 to cw 12.1 mm), 3 juveniles(cw 9.8 to cw 12.2 mm), 3 juvenilefemales (cw 12.8 to cw 14.2 mm), 6 males(cw 15 to cw 18.4 mm), 3 subadultfemales (cw 16.9 to cw 17.3 mm), 2 adultfemales (cw 17.8 to cw 18.4 mm), subadult female (damaged), ( NMU TRW1970.06);  4 subadultfemales (cw 15.9 to cw 18.2 mm), 7 males(cw 14.7 to cw 18.6 mm),  9.iii.1972( NMU  09.03.1972);  West Usambara Mountains, 3 kmnorth of Mazumbai, 1 specimen,  13.ii.1975, ( Dunbar) ( NMU TRW1975.01).   Diagnosis.Postfrontal crest distinct, granulated, complete; exorbital tooth small, low; epibranchial tooth small, granular, anterolateral margin immediately behind epibranchial tooth lined by granules; ischium of third maxilliped with deep vertical sulcus; thoracic sternal sulcus s3/s4 deep at sides, shallow across middle; sternite s4 with raised rounded marginal ridges at points where chelipeds articulate; dactylus of major cheliped of adult males slender; first carpal tooth on carpus of cheliped sharp spine; second carpal tooth sub­equal spine, followed by one or two small teeth; ventral margins of merus of pereiopod 1 both lined by large granules; distal meral tooth large, pointed; terminal article of gonopod 1 short, stout, tapering cone, in line with longitudinal axis of gonopod; terminal article of gonopod 1 covered entirely by fields of short spines or stiff bristles; lateral, medial folds both low, of equal size; dorsal membrane not visible.  Size.Small, with an adult size range beginning at cw 23 mm.     Typelocality.  Telphusa infravallata: Buloa, Usambara Mountains, Tanzania;  P. usambarae: Amani, Usambara Mountains, Tanzania.   Distribution.East and West Usambara Mountains, Tanzania.   Remarks.Identification of  P. infravallatuswas based on examination of the adult male typeof  Telphusa infravallata Hilgendorf, 1898(cw 23.4, cl 15.4, ch 7.4, fw 6.5 mm) (ZMB 11378). Bott (1955)synonymized  P. infravallatuswith  Potamon (Potamonautes) usambarae Rathbun, 1933, and this is accepted here following comparison of  P. infravallatusto the male cotype of  P. (P.) usambaraefrom the Usambara Mountains (cw 22.8 mm) (MCZ 7680).  Natural history and conservation status.The conservation status of  P. infravallatusis categorized as vulnerable (VU) ( Table 4) because it has a narrow range of occurrence and a restricted area of occupancy that are both below the thresholds for vulnerable (VU) ( IUCN 2004). It is difficult to estimate the population status and trends of this species, but its population is estimated to be declining (despite the material presented here), based on indirect measures such a relatively poor representation in museum collections and increasing habitat disturbance associated with growing human populations in the region. 1926-12-08 USNM A. Loveridge Tanzania East Usambara Mountains Amani 19 USNM 64108 1 1964-01-01 NMU J. N. Raybould Tanzania Amani East Usambara mountains 19 TRW1964.03 2 2 1966-05 NMU J. N. Raybould Tanzania East Usambara Mountains Amani 19 TRW1966.12 5 3 2 1967-02-18 NMU J. N. Raybould Tanzania Mlalo West Usambara Mountains Tewe 19 TRW1967.11 1 NMU Tanzania East Usambara Mountains Amani 19 TRW1970.06 20 2 9 6 3 1972-03-09 1972-09-03 1972-03-09 NMU Tanzania 19 11 7 4 1975-02-13 NMU Dunbar Tanzania West Usambara Mountains Mazumbai 19 TRW1975.01 1 [312,1211,1444,1470] Tanzania Tanzania 19 1 holotype