Potamonemus asylos Cumberlidge, 1993: 576 – 584 Ng et al. 2008: 171 Cumberlidge 2011a: 78 Cumberlidge 2011b: 190 Mvogo Ndongo et al. 2017b: 3 A new genus for the freshwater crab Potamonemus asylos Cumberlidgeı 1993 ı (Brachyura: Potamoidea: Potamonautidae) from Cameroonı Central Africaı with a key to the genera of the Potamonautinae Cumberlidge, Neil Mvogo Ndongo, Pierre A. Clark, Paul F. Daniels, Savel R. Journal of Natural History 2019 2019-05-10 53 11 659 676 84CPR (Cumberlidge, 1993) Cumberlidge & Mvogo Ndongo & Clark & Daniels 2019 Cumberlidge 1993 [388,785,140,166] Malacostraca Potamonautidae Buea GBIF Animalia Decapoda 7 665 Arthropoda species asylos comb. nov.   ( Figures 1(a,b), 4(a), 5(a,b,g), 6(a,b), 7(a,d) and 8(a,d,g))   Typespecies.  Potamonemus asylos Cumberlidge, 1993, by present designation.      Potamonemus asylos Cumberlidge, 1993: 576 –584, figs 3, 4, 5a –b, 6a –c, 8a –b; tables 2, 3; Cumberlidge 1999: figs 40C, 41C,F, 42C,F, 43C,F, 44C, 53G, 54 – 57, 61E, 65F, table IX;  Ng et al. 2008: 171;  Cumberlidge 2011a: 78, 80, 82, 86, table 6.1;  Cumberlidge 2011b: 190;  Mvogo Ndongo et al. 2017b: 3, table 1; Daniels et al. 2015, table 1.   Material examined  Type material. Cameroon:  Buea asylos( Cumberlidge, 1993) comb. nov. adult ♂ holotype, CW 27.6, CL 18.3, CH9.0, FW 7.5 mm, between Buea( 4.153484°N, 9.299551°E) and  Kumba( 4.638727°N, 9.441354°E), South-WestRegion, coll. R.H.L. Disney, 1969 ( NHM 1994.587donation from NMU 1969/1991).  Paratypes, 3 ♀♀, CWs 25.4, 23.7, 18.7 mm, 3 ♂♂, CWs 22.3, 20.1, 19.8 mm, between Buea( 4.153484°N, 9.299551°E) and  Kumba( 4.638727°N, 9.441354°E), South-WestRegion, coll. R.H.L. Disney, 1969 ( NHM 1994.588 – 591), DNA voucher specimens ( Daniels et al. 2015, table 1).  Adult ♂, CW 22.4, CL 15.8, CH6.8, FW 6.9 mm, Buea( 4.153484°N, 9.299551°E) Kumba area, South-WestRegion, coll. R. H.L. Disney, 1969 ( NMU TRW 1969.22), specimen photographed here.  Other material examined.  Adult ♀, CW 23.2, CL 17.2, CH7.4, FW 7.4 mm, Buea( 4.153484°N, 9.299551°E), Kumba area, South-West Region, coll. R.H.L.  Disney,  29 April 1969( NMU TRW 1969.13a).  Adult ♂, CW 19.8, CL 14.5, CH6.8, FW 6.9 mm, 3 subadult ♂♂, CWs 16.4, 15.6, 14.9 mm, subadult ♀, CW 15.3 mm, 9 juv ., Okia Stream, Kumba area, South-West Region, coll. R.H.L.  Disney,  9 May 1969( NMU TRW 1969.27). Adult ♂, CW 19.0 mm, 3 subadult ♂♂, CWs 18.4, 15.8, 12.6 mm, subadult ♀, CW 17.9 mm, 2 juv ., Okia Stream, Kumba area, South-West Region, coll. R.H.L.  Disney,  27 March 1969( NMU TRW 1969.29).  Limbé(formerly Victoria), South-West Region, 2 ♂♂, CWs 21.3, 20.1 mm, coll . E . Fickenday,  6 November 1912, ‘edible land crabs ’( ZIMK-3607).   Diagnosis Exorbital tooth absent where anterolateral margin meets lateral orbital margin ( Figures 1(a,b) and 4(a)); major cheliped dactylus broad, flattened, not arched ( Figures 1(b) and 5(a,b)); lower margin of cheliped merus with four large jagged pointed teeth ( Figures 1(b) and 6(a,b)); anterior corners of carapace surface smooth; carapace grooves shallow to absent ( Figures 1(a) and 4(a); Cumberlidge 1993, figs. 2a, 3a).   Description Same as for the genus and for  P. asylos comb. nov.(see Cumberlidge 1993, 1999).   Distribution   Buea asylos comb. nov.is endemic to the rainforest zone of south-western Cameroonbetween the towns of Kumba, Bueaand Limbé( Cumberlidge 1993, 1999).    Typelocality Between Bueaand Kumba, south-western Cameroon.   Ecology   Buea asylos comb. nov.is restricted to the humid lowland and montane rainforests of south-western Cameroonin the area near Mount Cameroon( 4095 masl) that has an annual average rainfall of more than 5000 mm( Mvogo Ndongo et al. 2017a, 2017b).   Remarks Significant morphological differences between  B. asylos comb. nov.,  P. mambilorumand  P. sachsiwere found in the G1, G2 and mandible ( Figures 7(a –f) and 8(a –c,g –i)) that are used here to define  Buea gen. nov.Other noteworthy characters of  B. asylos comb. nov.include those of the chelipeds and carapace of that set it apart from the two species of  Potamonemus: the cheliped merus lower medial margin has large jagged teeth ( Figure 6(a,b)) (vs small granules in  Potamonemus, Figure 6(c,f)), the cheliped carpus medial margin of  B. asylos comb. nov.has a small but distinct pointed proximal tooth ( Figure 5(g)) (vs a small granule-sized tooth in  Potamonemus, Figure 5(h,i)), the cheliped dactylus is distinctly broadened ( Figures 1(b) and 5 (a)) (vs distinctly slim or arched in  Potamonemus, Figure 5(c,e)), and the carapace proportions of  B. asylos comb. nov.are wider (CW/FW 3.35, vs 3.08 –3.12), longer (CW/FW 2.32, vs 2.22 –2.25), and higher (CW/FW 1.10, vs 0.96 –1.07) than in  Potamonemus.  Conservation status The extinction risk status of  B. asylos comb. nov.was assessed in 2008 using the International Union for the Conservation of Nature (IUCN) Red List protocols ( Cumberlidge 2008a) as Data Deficient (DD) in view of the lack of information on its extent of occurrence (EOO), ecological requirements, population size, population trends and long-term threats ( Cumberlidge 1993, 2011a, 2011b; Cumberlidge et al. 2009; IUCN 2012). The three locations available in this study give a recalculated EOO of 142 km 2, and an area of occupancy (AOO) of 12 km 2, using GeoCAT (http://geocat.kew.org; Bachman et al. 2011), but these are still probably underestimates given the paucity of the locality data (but if taken alone would point to a Red List threatened category). The extinction risk status of  P. mambilorum(seven locations, EOO 43,291 km 2; Cumberlidge 2008b) and  P. sachsi(four locations, EOO 24,219 km 2; Cumberlidge 2008c) were assessed in 2008 ( Cumberlidge 2008b, 2008c) as Least Concern (LC) and Vulnerable (VU), respectively, ( Cumberlidge 1993, 2011a, 2011b; Cumberlidge et al. 2009; IUCN 2012). Although the recalculations of the EOO and the AOO for these three species do not in themselves warrant a reassessment of their extinction risk, there is reason to believe that the threat status of these species may have intensified since the last assessment. For example, recent field work in the wetland ecosystems of the South-Westand Littoral regions of Cameroonby the second author indicates that these habitats are being impacted by deforestation and by intensive agricultural practices that are severely altering the flow patterns of small streams and impacting the aquatic biodiversity ( Mvogo Ndongo et al. 2017a, 2017b, 2017c, 2018). Awareness of these current threats to the habitats of  B. asylos comb. nov.,  P. mambilorumand  P. sachsimeans that each of these taxa is likely to be reassigned to a more threatened category once new IUCN Red List extinction risk assessments have been carried out. There is a need for further field research specifically aimed at gathering the data needed for an extinction risk assessment of these littleknown endemic species from this understudied biodiversity hotspot. 2571117011 South-West Switzerland 4.638727 Kumba 1 9.441354 7 665 1 1 holotype 2571117010 [160,838,556,580] South-West Switzerland 4.638727 Kumba 1 9.441354 7 665 1 1 holotype 2569344767 NHM, NMU Switzerland 7 665 NHM 1994.587, NMU 1969 1 holotype 2571117008 South-West Switzerland 4.638727 Kumba 1 9.441354 7 665 6 3 3 paratype 2571117009 South-West Switzerland 4.638727 Kumba 1 9.441354 7 665 6 3 3 paratype 2569344771 NHM Switzerland 7 665 NHM 1994.588, 591 1 paratype 2569344768 South-West Switzerland 4.153484 Adult 1 9.299551 Kumba area 7 665 1 1 paratype 2569344775 [210,945,764,788] NMU Switzerland 7 665 TRW 1969.22 1 paratype 2569344765 Adult Switzerland 4.153484 Kumba area 1 9.299551 South-West Region 7 665 1 1 2569344774 1969-04-29 NMU Disney Switzerland 7 665 TRW 1969.13 1 2569344776 Adult Switzerland CH 7 665 6 1 2 3 2569344766 Okia Stream Switzerland Kumba area South-West Region 7 665 1 2569344772 [522,995,973,997] 1969-05-09 NMU Disney Switzerland 7 665 TRW 1969.27 1 2569344763 [1091,1095,1007,1031] Okia Stream Switzerland Kumba area South-West Region 7 665 1 2569344770 1969-03-27 NMU Disney Switzerland 7 665 TRW 1969.29 1 2569344773 [268,1127,1076,1101] Limbe & Victoria Switzerland South-West Region 7 665 2 2 2569344777 [1126,1153,1077,1101] Limbe & Victoria Switzerland true South-West Region 7 665 1 2569344778 1912-11-06 ZIM Fickenday Switzerland 7 665 1