taxonID	type	description	language	source
775887904524FFC5FE576CE25BBA024E.taxon	description	(Figures 1, 3 – 8; Tables 1, 3)	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
775887904524FFC5FE576CE25BBA024E.taxon	materials_examined	Material examined Type material. Holotype: TANZANIA: adult ♂ (CW 55.6 mm), Itamba Crater Lake, Mbeya District (033.8427 ⁰ E, 824 m ASL), coll. M. J. Genner, 19 July 2011 (NHMUK 2018.308). Paratypes: TANZANIA: subadult ♂ (CW 41.1 mm) Itamba Crater Lake, Mbeya District (033.8427 ⁰ E, 824 m ASL), coll. M. J. Genner, 19 July 2011 (NHMUK 2018.307); TANZANIA: subadult ♂ (CW 46.3 mm), Itamba Crater Lake, Mbeya District (09.3522 ⁰ S, 033.8427 ⁰ E ASL), coll. M. J. Genner, 19 July 2011 (NHM 2018.314); TANZANIA: 2 subadult ♂♂ (CW 47.8 mm 2025.1169; 31.4 mm, NHMUK 2025.1170), subadult ♀ (CW 23 mm) (NHMUK 2025.1168) Itamba Crater Mbeya District (09.3522 ⁰ S, 033.8427 ⁰ E, 824 m ASL), coll. M. J. Genner, 22 November 2011; subadult ♀ (CW 44.4 mm), Itamba Crater Lake, Mbeya District (09.3522 ⁰ S, 033.8427 ⁰ E, 824 m ASL M. J. Genner, 19 July 2011 (NHMUK 2018.315). Other material. TANZANIA: adult ♀ (CW 61 mm), Kyungululu Crater Lake, Mbeya District, coll. M. J. 18 July 2011 (NHMUK 2018.324); TANZANIA: adult ♂ CW 56.8 mm, Kyungululu Crater Lake, Mbeya (09.308 ⁰ S, 033.8655 ⁰ E, 927 m ASL), coll. M. J. Genner, 18 July 2011 (NHM 2018.310); TANZANIA: adult 54.0 mm), Kyungululu Crater Lake (09.308 ⁰ S, 033.8655 ⁰ E), coll. M. J. Genner, 18 July 2011 (NHMUK TANZANIA: adult ♀ (CW 51.6 mm, NHMUK 2025.1212) Itamba Crater Lake, Mbeya District (033.8427 ⁰ E, 824 m ASL), coll. M. J. Genner, July 2011; TANZANIA: 13 adult ♂♂ (CWs in mm): 58.3 (2025.1189), 57.3 (NHMUK 2025.1206), 56.4 (NHMUK 2025.1208), 56.2 (NHMUK 2025.1213), 54.6 (2025.1192), 54.5 (NHMUK 2025.1182), 53.2 (NHMUK 2025.1198), 53.1 (NHMUK 2025.1186), 51.9 (2025.1210), 51.4 (NHMUK 2025.1205), 49.0 (NHMUK 2025.1199), 48.6 (NHMUK 2025.1201), 7 subadult (CWs 46.3, 45.0, 44.5, 43.4, 43.36, 43.1, 39.0 mm), 17 adult ♀♀ (CWs in mm): 58.9 (NHMUK 2025.1176 HISTORY (NHMUK 2025.1193), 49.6 (NHMUK 2025.1209), 49.3 (NHMUK 2025.1174), 47.3 (NHMUK 2025.1194 District (09.3522 ° S, 033.8427 ° E), coll. M. J. Genner, 19 July 2011; TANZANIA: 1 specimen, subadult 38.0 mm, NHMUK 2025.1239) Itupi East stream (09.31 ° S, 033.77 ° E, 1,116 m ASL), coll. G. Turner, 2 July TANZANIA: 1 specimen, Kyungululu Crater Lake (09.308 ° S, 033.866 ° E), coll. M. J. Genner, 18 July TANZANIA: subadult ♀ (CW 31.0 mm), Masoko Crater Lake (09.332 ° S, 033.756 ° E, 861 m ASL M. J. Genner (July 2018) (NHMUK 2025.1240); TANZANIA: adult ♂ (CW 52.0 mm, NHMUK subadult ♀ (CW 40.1 mm, NHMUK 2025.1217), Nkokwa (09.520 ° S, 033.785 ° E, 522 m ASL P. N. Gabagambi, 20 November 2020; TANZANIA: 2 subadult ♂♂ (CW 45.2 mm (NHMUK 31.9 mm (NHMUK 2025.1223), 4 subadult ♀♀ (CW 45.9 mm (NHMUK 2025.1218), 37.1 mm (2025.1220), 33.2 mm (NHMUK 2025.1219), 31.9 mm (NHMUK 2025.1222), Nguwesi River (033.827 ° E, 568 m ASL), coll. P. N. Gabagambi, 20 November 2020; TANZANIA: adult ♀ (CW (NHMUK 2025.1225), 5 subadult ♂♂ (CWs 48.0 mm (NHMUK 2025.1230), 39.0 mm (NHMUK 44.0 mm (NHMUK 2025.1229), 36.4 mm (NHMUK 2025.1227), 35.0 mm (NHMUK 2025.1228), 3 subadult (CWs 41.6 mm (NHMUK 2025.1226), 40.0 mm (NHMUK 2025.1232), 38.0 mm (NHMUK 2025.1224) River (09.363 ° S, 033.853 ° E, 763 m ASL), coll. P. N. Gabagambi, 19 November 2020. ZAMBIA: 4 juveniles 14.0 mm (NHMUK 2025.1233), 22.0 mm (NHMUK 2025.1234), 18.0 mm (NHMUK 2025.1235), (NHMUK 2025.1236) Chilonga (12.16 ° S, 031.232 ° E, 1,390 m ASL), coll. M. J. Genner, 17 June 2010; subadult ♂ (CW 24.0 mm (NHMUK 2025.1238), juvenile (CW 18.0 mm (NHMUK 2025.1237), Kaombe (030.769 ° E, 1,549 m ASL), coll. M. J. Genner, 17 June 2010.	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
775887904524FFC5FE576CE25BBA024E.taxon	diagnosis	Diagnosis Exorbital tooth small, low; epibranchial tooth rounded, granular; anterolateral carapace margin small granules (Figure 4 (a, b )); carapace lateral margin behind epibranchial tooth lined by small margin curving strongly inward posteriorly over carapace surface (Figure 4 (a, b )); postfrontal crest smooth, completely traversing carapace between epibranchial teeth; posterior surface of carapace with urogastric, cardiac grooves; carapace branchiostegite suborbital, subhepatic, pterygostomial smooth; vertical, epimeral sutures marked by small granules (Figure 5 (b )); third maxilliped ischium deep vertical sulcus (Figure 5 (a )); thoracic sternal sulcus S 3 / 4 deepest at sides, shallow in middle (Figure 5 (a )); margins of dactylus, propodus pollex of both chelae lined by distinct rounded teeth large teeth proximally, interspersed by medium-sized rounded teeth (Figure (6 (a – c )); cheliped carpus margin distal tooth large, slim, pointed, proximal tooth medium-sized, pointed (Figure 3 (a )); cheliped lower margins lined by large granules, distal meral tooth spinelike; P 2 – 5 carpus, propodus, and dactylus elongated (Figure 6 (c )). G 1 TA midpart raised by thin high dorsal crest formed from medial margin of lobe (Figure 7 (a, b )), G 1 TA midpart broadened by wide gutter running between medial, lateral dorsal lobe (Figure 7 (d )); G 1 TA distal third slim; ventral, dorsal lobes both low, tapering to pointed tip (Figures 7 (a, b) and 8 (a, b, d – f )).	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
775887904524FFC5FE576CE25BBA024E.taxon	description	Description Carapace arched, height greater than front width (CH / FW 1.3); carapace length 1.5 × carapace width 1.5); exorbital tooth small, low; epibranchial tooth rounded, granular; anterolateral carapace margin small granules (Figure 4 (a, b )); carapace lateral margin behind epibranchial tooth lined by small granules, curving strongly inward posteriorly over carapace surface (Figure 4 (c, d )); postfrontal crest distinct, completely traversing carapace between epibranchial teeth; posterior surface of carapace with deep cardiac grooves; carapace branchiostegite suborbital, subhepatic, pterygostomial regions all smooth; epimeral sutures marked by small granules (Figure 5 (b )). Epistomial tooth prominent, granulated, (Figure 4 (b )). Mandibular palp consisting of basis and two articles; terminal article undivided, with hardened ridge along superior margin originating at article junction (Figure 6 (d )). Third maxilliped with deep vertical sulcus (Figure 5 (a )). Thoracic sternal sulcus S 3 / 4 reduced to two short deep sulci, middle obscure (Figure 5 (a )); episternal sulcus S 4 / E 4 obscure, S 5 / E 5, S 6 / E 6, S 7 / E 7 faint, incomplete (Figure 6 (b chela dactylus (moveable finger) arched, propodus pollex (fixed finger) thick, broad, leaving ovoid between fingers when closed; margins of dactylus, margins of propodus pollex of both chelae lined by HISTORY longest, P 5 shortest (Figure 3 (b )); P 2 – 5 dactyli tapering to pointed tip, each bearing four rows of pointing, short, sharp spines (Figure 3 (b )). G 1 TA length about one-third G 1 SA length (G 1 TA / G 1 SA 0.4), outward at 45 ° to longitudinal axis of G 1 SA; G 1 TA lateral margin lined with short setae; G 1 TA ventral, dorsal lobes; ventral lobe low, slim, not raised, not widened, extending from G 1 SA-G 1 TA HISTORY of dorsal lobe (Figure 7 (d )); G 1 TA distal third slim; ventral, dorsal lobes both low, tapering to pointed tip (Figures 7 (a, b) and 8 (a, b, d – f )). G 1 SA medial margin lined by conspicuous setae, lateral margin with short setae. G 1 SA ventral side with horizontal margin at G 1 TA-G 1 SA junction; G 1 SA dorsal side with indentation filled by conspicuous dorsal membrane. G 2 SA long, slim, subequal to G 1 SA; G 2 SA widest tapering sharply inward about one-third along length, last two-thirds forming long, thin, tapering, process supporting elongated flagellum-like G 2 TA (G 2 TA / G 2 SA 0.6) (Figures 7 (c) and 8 (c )).	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	description	(Figures 2, 9 – 14, Tables 1 – 3)	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	materials_examined	Material examined Type material. Holotype: MALAWI: adult ♂ (CW 65.5, CL 44.2 mm, CH 21.8, FW 16.6 mm), Cholo Cholo District (16.076 ° S, 035.050 ° E) coll. A. Loveridge, 26 March 1949 (MCZ 12611). Other material. MALAWI: 3 subadult ♂♂ (CWs 25.2 mm to 49.5 mm), 2 subadult ♀♀ (CWs 37.5, 42.9 adult ♂♂ (CWs 57.7, 67.6 mm), 8 adult ♀♀ (CWs 51.5 to 67.9 mm), Zomba District (( 15.4991 ° S coll. E. Lawrence, 28 June 1938 (NHM 1938.6.28.9 – 16). MALAWI: subadult ♂ (CW 48.5 mm), adult 50.4 mm), Mulunguzi near Zomba (15.3798 ° S 035.3340 ° E), coll. R. C. H. Sweeney, December 1963 1969.893). MALAWI: 2 subadult ♂♂ (CWs 47.5, 34.2 mm), Nkhata Bay (11.6026 ° S 034.2951 ° E), coll. 1956 (NHM 1956.65.9). MALAWI: subadult ♀ (CW 25.8 mm), Zomba (15.3844 ° S 035.3420 ° E, 610 – 914 coll. H. H. Johnston, 2 February 1894 (NHM 1894.2.2.1). MALAWI: subadult ♂ (CW 42.1 mm), subadult 44 mm), Mulanje, stream flowing through Tea Estate (16.027 ° S, 35.517 ° E) coll. G. Fryer, 5 June 1956 1956.6.5.7 – 8). MALAWI: 2 adult ♀♀ (CWs 64.9, 56.3 mm), 3 subadult ♀♀ (CWs 26.1 to 35.4 mm), 7 ♂♂ (CWs 15.3 to 27.7 mm), juvenile ♂ (CW 10.6 mm), coll. D. J. Lewis, January 1960 (NHM 2011.1522 MALAWI: subadult ♀ (CW 43 mm), Magombo (14.991 ° S, 34.951 ° E), coll. D. J. Lewis (NHM MALAWI: subadult ♀ (CW 33.2 mm), Rukuru River flowing into the western shore of Lake Malawi (S, 34.262 ° E), coll. A. J. Davy and W. S. Atkins, 2011 (NHM 2011.1510); MALAWI: 3 subadult ♀♀ (CWs HISTORY Diampwe River, Central Province (14.136 ° S, 34.088 ° E), coll. G. Fryer, 5 June 1956 (NHM 1956.6.5.4 MALAWI: subadult ♀ (CW 24.6 mm), subadult ♂ (CW 23 mm), 5 April 1952 (NHM 1952.4.5.1); northern Malawi, subadult ♀ (CW 30.4 mm), subadult ♂ (CW 42.2 mm), coll. Sir H. H. Johnson, 29 April (NHM 1897.4.29.2 – 3); MALAWI: 2 juvenile ♂♂ (CW 15.7 mm (NHMUK 2025.1128), 18.9 mm (2025.1129), subadult ♀ (CW 33.0 mm (NHMUK 2025.1130), Matsimbe 14.186 ° S, 33.672 ° M. J. Genner, 10 June 2010; MALAWI: subadult ♂ (CW 36.5 mm, Mikolongwe (15.886 ° S, 35.200 M. J. Genner, 17 May 2010 (NHMUK 2025.1136); MALAWI: 3 subadult ♂♂ (CWs 34.3 mm (NHMUK 16.6 mm (NHMUK 2025.1132), 22.9 mm (NHMUK 2025.1134) 2 subadult ♀♀ (CWs 21.5 mm (2025.1133), 22.1 mm (NHMUK 2025.1135), Domasi (15.304 ° S, 35.372 ° E) coll. M. J. Genner, 15 May TANZANIA: 12 adult ♂♂, CWs in mm (CW 60.2 (NHMUK 2025.1150), CW 58.0 (NHMUK 2025.1152), (NHMUK 2025.1148), CW 56.4 (NHMUK 2025.1143), CW 55.6 (NHMUK 2025.1153), CW 54.9 (2025.1142), CW 54.3 (NHMUK 2025.1160), CW 52.5 (NHMUK 2025.1149), CW 52.4 (NHMUK 2025.1147 51.8 (NHMUK 2025.1157), CW 50.9 (NHMUK 2025.1162), CW 50.2 (NHMUK 2025.1166), 12 adult ♀♀ in mm (CW 62.5 (NHMUK 2025.1165), CW 61.8 (NHMUK 2025.1155), CW 58.0 (NHMUK 2025.1144), (NHMUK 2025.1156), CW 57.2 (NHMUK 2025.1151), CW 56.0 (NHMUK 2025.1164), CW 55.7 (2025.1163), CW 55.4 (NHMUK 2025.1158), CW 55.4 (NHMUK 2025.1161), CW 55.1 (NHMUK 2025.1154 54.0 (NHMUK 2025.1159), CW 53.5 (NHMUK 2025.1141); subadult ♀ CW 45.2 mm (NHMUK subadult ♂ CW 43.1 mm (NHMUK 2025.1145) River Mwalalo (9.480 ° S, 34.033 ° E), coll. P. N. 16 November 2020; TANZANIA: subadult ♂ (CW 38.4 mm), coll. J. Kingdon, November 1989 (NMU XI. 1989). MALAWI: subadult ♂ (CW 45.2 mm), adult ♀ (CW 53 mm), Muloza West, Cholo area (35.761 ° E), coll. M. J. Roberts, 15 September 1988 (NMU 15.09.1988). ZAMBIA: 2 subadult ♀♀ (CW (NHMUK 2025.1138), CW 26 mm (NHMUK 2025.1140), 2 subadult ♂♂ (CW 29.0 mm (NHMUK 24.0 mm (NHMUK 2025.1137), Chipata (13.656 ° S, 32.655 ° E), coll. M. J. Genner, 20 June 2010. subadult ♂ (CW 46.5 mm), Inyanga, from River Mare in the Eastern Highlands (18.213 ° S, 1,700 – 1,829 m ASL) near government trout hatchery, coll. T. R. Williams, 7 March 1972 (NMU 7. III MOZAMBIQUE: subadult ♂ (CW 45.2 mm), coll. H. B. Cott, 5 March 1929 (NHM 1929.3.5.14 – 15).	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	diagnosis	Diagnosis Based on holotype. Exorbital tooth small, low; epibranchial tooth small, granular; anterolateral carapace by granules (Figures 9 (a, b), 10 (a, b), 11 (a, b) and 12 (a, b )); carapace lateral margin posterior to tooth lined with granules, curving strongly inward posteriorly over carapace surface (Figures 9 (a) and 12 (a )); postfrontal crest distinct, lined by granules, completely traversing carapace between teeth; posterior surface of carapace with deep urogastric, cardiac grooves (Figures 9 (a) and 11 (a )); branchiostegite suborbital region with granules on surface, subhepatic region with granules, surface, branchiostegite suborbital region with granules on surface, subhepatic region with granules, on surface, pterygostomial region smooth except for line of granules close to granular epimeral (Figures 10 (b) and 12 (b )). Third maxilliped ischium with deep vertical sulcus (Figure 12 (e )); thoracic sulcus S 3 / 4 reduced to two short deep sulci, middle part obscure (Figures 9 (b) and 11 (b, c )); dactylus, propodus pollex of both chelae lined by distinct rounded teeth, 3 large teeth proximally chela fixed finger with 3 large rounded teeth proximally, interspersed by medium rounded teeth (Figure d )); cheliped carpus inner margin distal tooth large, slim, pointed, proximal tooth very small, (Figure 10 (c, d) and 11 (a )); cheliped merus lower margins lined by large granules, distal meral tooth like (Figure 10 (c, d) and 12 (f, g )); P 5 carpus, propodus, and dactylus not elongated (Figure 11 (a )) midpart raised by thin high dorsal crest formed from medial margin of dorsal lobe (Figure 7 (a, b midpart broadened by long wide gutter running between medial, lateral margins of dorsal lobe (Figure G 1 TA distal third slim, ventral, dorsal lobes low, tapering to pointed upcurved tip (Figures 13 (a, b) and f )); horizontal margin on G 1 ventral side at G 1 TA-G 1 SA junction (Figures 13 (a) and 14 (f )); U-shaped tion filled with conspicuous dorsal membrane on G 1 SA dorsal side (Figure 14 (a – c )); margins of G 1 TA lined by setae (Figure 13 (a, b )). HISTORY d = 25.3 mm; e = 14.2 mm. granules (Figures 9 (a, b), 10 (a, b), 11 (a, b) and 12 (a, b )); carapace lateral margin posterior to epibranchial lined by granules, curving strongly inward posteriorly over carapace surface (Figures 9 (a), 11 (a) and postfrontal crest distinct, lined by granules, completely traversing carapace between epibranchial posterior surface of carapace with deep urogastric, cardiac grooves (Figures 9 (a), 10 (a), 11 (a) and carapace branchiostegite suborbital region with granules on surface, subhepatic region with carinae on surface, branchiostegite suborbital region with granules on surface, subhepatic region granules, carinae on surface, pterygostomial region smooth except for line of granules close to epimeral suture (Figures 10 (b) and 12 (b )). Epistomial tooth prominent, granulated, V-shaped (Figures and 12 (b )). Mandibular palp consisting of basis plus two articles; terminal article simple, undivided, lobe or ridge at junction between articles (Figure 13 (d – f )). Third maxilliped ischium with deep vertical (Figure 12 (e )); thoracic sternal sulcus S 3 / 4 reduced to two short deep sulci, middle part obscure (Figures and 11 (b, c )); episternal sulci S 4 / E 4 obscure, S 5 / E 5, S 6 / E 6, S 7 / E 7 faint, incomplete (Figures 9 (b) and Major chela dactylus (moveable finger), propodus pollex (fixed finger) thick, broad, leaving long thin space between fingers when closed; margins of dactylus, propodus pollex of both chelae lined by rounded teeth margins of both fingers lined by distinct rounded teeth, three large teeth (Figure 10 (c, d )); cheliped carpus inner margin distal tooth large, slim, pointed, proximal tooth small, (Figures 10 (c, d) and 11 (a )); cheliped merus lower margins lined by large granules, distal meral tooth like (Figures 10 (c, d) and 12 (f, g )); P 5 carpus, propodus, and dactylus not elongated (Figure 11 (a )); P 3 HISTORY e = 2.0 mm; f = 2.0 mm. telson narrow triangle with rounded apex, pleomeres PLl – 6 quadrate (Figure (11 (b, c )). G 1 TA length one-third G 1 SA length (G 1 TA / G 1 SA 0.4), angled outward at 45 ° to longitudinal axis of G 1 SA; lateral G 1 TA lined by short setae; G 1 TA ventral lobe low, not raised, not widened, extending from G 1 junction to G 1 TA tip; G 1 TA slim basally, dorsal, ventral lobes both low, not widened (Figures 13 (a, b) (a – f )); G 1 TA midpart higher, wider; height due to dorsal crest formed from thin, high medial margin of lobe (( Figures 13 (a, b) and 14 (a – f )); G 1 TA midpart width due to wide gutter running longitudinally medial, lateral margins of dorsal lobe (Figure 14 (d )); G 1 TA distal third slim, ventral, dorsal lobes low, to pointed upcurved tip (Figures 13 (a, b) and 14 (a – f )); horizontal margin on G 1 ventral side at G 1 HISTORY to G 1 SA; G 2 SA widest at base, tapering sharply inward about one-third along length, last two-thirds long, thin, tapering, upright process supporting long flagellum-like G 2 TA (G 2 TA / G 2 SA 0.6) (Figure	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	description	Size Large species, adult size range between CW 50 to 67 mm. Colour The carapace, ambulatory legs and claws of living specimens range from green-brown to Preserved specimens are uniformly light brown (Figures 9 (a) and 11 (a )).	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	distribution	Distribution Arcopotamonautes montivagus s. s. occurs in Tanzania, East Africa and in four neighbouring countries (Mozambique, Zambia, and Zimbabwe) in southern Africa (Figure 2). Notably, this species is reported Rungwe Mountains in southern Tanzania and in the rivers draining south from there into the north Zomba, and Cholo mountain). This river-living species has never been collected in Lake Malawi. a few reports of A. montivagus s. s. from Mozambique, Zambia, and Zimbabwe (Figure 2). Comparisons Arcopotamonautes itamba and A. montivagus are morphologically similar as would be expected of of a species complex. Comparisons of a number of morphometric characters based on the dimensions carapace and pereiopods P 1 – 5 of these two species found only minor differences between them (et al. 2024: figs 3 A, 4 B). Morphological characters shared by A. itamba and A. montivagus include distal and proximal teeth on the inner margin of the cheliped carpus; a pointed distal meral tooth cheliped merus; a major chela with an arched dactylus; a complete and distinct postfrontal crest grooves on the posterior surface of the carapace; a low exorbital tooth with a granulated margin; a sized epibranchial tooth; a carapace lateral margin that is either smooth or has fine granulations; maxilliped ischium with a deep vertical sulcus; a sternal sulcus S 3 / 4 that is deep at the sides and the centre, a G 1 TA with a conspicuous thin high dorsal crest on the medial margin of the dorsal a G 1 TA that terminates in an upcurved tip.	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	description	Arcopotamonautes itamba can be distinguished from A. montivagus by smooth carapace branchiostegite suborbital, subhepatic, pterygostomial regions (Figures 3 (b), 4 (b) and 5 (a )) (vs fields of granules and in the branchiostegite suborbital and subhepatic regions, and a smooth pterygostomial region (a line of granules parallel to the granulated epimeral suture) in A. montivagus (Figures 9 (b), 10 (a, b), 11 12 (a, b )) and by the elongated P 5 ambulatory leg segments in A. itamba (Figure 3 (a, b )) (vs the ambulatory leg segments in A. montivagus (Figure 11 (a )). These two taxa have distinct and non-overlapping geographical distributions (Figures 1 and 2), although specimens of A. montivagus and A. itamba have reported to occur less than 30 km apart in southern Tanzania, from the Mwalalo and Mguwusi respectively. Arcopotamonautes montivagus and A. itamba are both found mainly in the rivers and lakes of Malawi drainage, and both share some morphological characters with A. orbitospinus, the Malawi endemic to Lake Malawi. Characters shared by these three taxa include two spines on the inner margin cheliped carpus (distal tooth larger than proximal tooth), a pointed distal meral tooth on the cheliped and a major chela with an arched dactylus. Additional characters shared by these two species A. orbitospinus include a complete and distinct postfrontal crest, deep grooves on the posterior the carapace, an exorbital tooth with a granulated margin, a deep vertical sulcus on the ischium of maxilliped, a G 1 TA with a conspicuous thin high dorsal crest on the medial margin of the dorsal a G 1 TA whose slim tapering distal third terminates in an upcurved tip.	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	description	A. montivagus (Figures 5 (a, b) and 11 (b, c )) (vs a complete and deep S 3 / 4 in A. caputanatis cf. et al. 2019, fig. 1 B, and in P. mulanjeensis cf. Daniels and Bayliss 2012, fig. 5 B).	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	discussion	Remarks Bott (1955) treated Potamon (Potamonautes) montivagus Chace as a junior synonym of Arcopotamonautes johnstoni (Miers). This, however, was not accepted by subsequent authors, such as Reed and (2006), following their comparison of the holotype of P. (P.) montivagus (MCZ 12611) with the Thelphusa depressa var. johnstoni Miers (NHM 1885.2). This present study agrees with Reed and (2006), Ng et al. (2008), and Cumberlidge and Daniels (2022) that A. montivagus s. s. is a valid species rejects Bott’s (1955) opinion that this taxon is a junior subjective synonym of A. johnstoni (Miers, 1885 Habitat	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
77588790452DFFDBFDFE6CDB5A370207.taxon	description	Arcopotamonautes montivagus s. s. is found in rivers or shallow-lake environments proximate to Lake with the closest specimen to the lake from the River Mwalalo, about 2 km upstream from Matema Malawi (Figure 2). It has also been recorded in rivers in Zambia, Zimbabwe and Mozambique. This species has never been collected in Lake Malawi, while the Lake Malawi species A. orbitospinus is Lake Malawi and has never been reported from rivers or streams (Cumberlidge et al. 2012). The stout P 2 – 5 ambulatory leg segments of A. montivagus s. s., a river-living species (Figure 11 (a )), may adaptation for better locomotion between the rocky beds of fast-flowing rivers and streams. Conservation status Arcopotamonautes montivagus s. s. was most recently assessed for the IUCN Red List of Threatened 2018 (as A. montivagus s. l.), and listed as Least Concern (LC) (Cumberlidge 2018). This was a change previous assessment in 2008 when it was initially listed as VU but this species was later downlisted to LC based on recent collections of specimens from new localities in five different countries (Figure 2 collections expanded the number of localities from seven to 18, and increased the number of countries this species from one (Malawi) to five (with the addition of Tanzania, Mozambique, Zimbabwe, and The present division of A. montivagus s. l. into two taxa (A. montivagus s. s. and A. itamba sp. n.) does not the extinction risk assessment of A. montivagus s. s. because only a few specimens of A. montivagus s transferred to A. itamba sp. n. and the EOO of A. montivagus s. s. (557,115 km 2) remains well threshold for LC. Arcopotamonautes montivagus s. s. occurs in three protected areas, where its habitat is unlikely disturbed: in Zimbabwe (Rhodes Inyanga National Park), Malawi (Mulanje Mountain Forest Reserve Tanzania (Uwanda Game Reserve). Arcopotamonautes montivagus s. s. is not collected for food, and no known current threats. Updated checklists The addition of the new species in this work means that the updated freshwater crab checklist for (Table 1) comprises 32 species, five genera, and two families (Hilgendorf 1898; Rathbun 1933; Chace Bott 1955; Reed and Cumberlidge 2006; Gereau et al. 2016; Cumberlidge et al. 2012; Cumberlidge Daniels 2022; Cumberlidge and Conners 2024; Cumberlidge and Jonas 2024). Four of these genera are African family Potamonautidae Bott 1970 (Arcopotamonautes Bott, 1955; Platythelphusa A. Milne-Edwards 1887; Rotundopotamonautes Bott, 1955; and Maritimonautes; Cumberlidge and Daniels, 2022), while genus, Deckenia Hilgendorf, 1869, is in the Afrotropical family Deckeniidae Ortmann, 1897 (Cumberlidge Daniels, 2022). The updated freshwater crab checklist for Malawi (Table 2) comprises seven species: Arcopotamonautes Bott, 1955; two in Maritimonautes Cumberlidge and Daniels, 2022, and Potamonautes MacLeay, 1838. All three genera are assigned to the Potamonautidae Bott, 1970 1953; Cumberlidge and Daniels 2022). The updated freshwater crab checklist for Zambia (Table 3) comprises 12 species:	en	Cumberlidge, Neil, Krajenka, Grace E., Clark, Paul F., Layfield, Harry J., Genner, Martin J. (2025): Redescription of the African freshwater crab Arcopotamonautes montivagus (Chace) (Potamoidea: Potamonautidae: a description of a new species, and updated species checklists Tanzania, Malawi, and Zambia. Journal of Natural History 59 (45 - 48): 2545-2569, DOI: 10.1080/00222933.2025.2575216, URL: https://doi.org/10.1080/00222933.2025.2575216
