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"A revision of the freshwater of , East ."

Neil Cumberlidge Northern Michigan University

Kirstin S. Meyer

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The freshwater crabs of Lake Kivu (Crustacea: : Brachyura: ) Neil Cumberlidgea; Kirstin S. Meyera a Department of Biology, Northern Michigan University, Marquette, Michigan, USA

Online publication date: 08 June 2011

To cite this Article Cumberlidge, Neil and Meyer, Kirstin S.(2011) 'The freshwater crabs of Lake Kivu (Crustacea: Decapoda: Brachyura: Potamonautidae)', Journal of Natural History, 45: 29, 1835 — 1857 To link to this Article: DOI: 10.1080/00222933.2011.562618 URL: http://dx.doi.org/10.1080/00222933.2011.562618

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The freshwater crabs of Lake Kivu (Crustacea: Decapoda: Brachyura: Potamonautidae) Neil Cumberlidge∗ and Kirstin S. Meyer

Department of Biology, Northern Michigan University, Marquette, Michigan 49855, USA

(Received 31 July 2010; final version received 9 February 2011; printed 2 June 2011)

Lake Kivu is a volcanic barrier lake in the East African whose freshwater fauna (Potamonautidae) is largely undocumented. The present taxonomic revision revealed four species of freshwater crabs from Lake Kivu: idjwiensis (Chace, 1942), Potamonautes mutandensis (Chace, 1942), Potamonautes lirrangensis (Rathbun, 1904) and Potamonautes bourgaultae,sp. nov. Potamonautes idjwiensis and P. mutandensis are redescribed and distributional maps of all four species are provided. The four species are compared with each other, each species is illustrated, and a key to the species is included. The diversities of the African Great are also briefly compared. Keywords: Potamoidea; Potamonautidae; Potamonautes; Lake Kivu; redescrip- tion; identification key;

Introduction This study focuses on the taxonomy of the largely undescribed freshwater crab fauna of Lake Kivu (2700 km2, elevation 1460 m), one of a series of lakes associated with the Valley in (Table 1). Lake Kivu lies surrounded by mountains on the floor of the Western Rift Valley, partly in the Democratic Republic of Congo and partly in . The lake is over 89 km long, 48 km wide, and has an average depth of 240 m. The part of Lake Kivu in the Democratic Republic of Congo includes island (the world’s 10th largest inland island) and the shoreline settlements of , Kabare, Kalehe, Sake and , whereas the shoreline settle-

Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 ments in Rwanda include , Kibuye and Cyangugu. Hydrologically, Lake Kivu is part of the basin and the lake drains south into Lake via the . Historically, Lake Kivu was part of the River basin (as the-then northward-flowing River that drained into ) until the river was blocked by late Pleistocene volcanism and the lake was formed, together with and a number of other small volcanic barrier lakes in southwest (Beadle 1981). The shoreline of Lake Kivu is mostly rocky with submerged rocks encrusted with calcium carbonate from the relatively high salt levels in the lake (Beadle 1981). Kivu is a deep basin lake with a narrow littoral zone (where there are abundant algae, macrophytes, invertebrates and fish) and steep sides that drop off sharply into deeper water (Beadle 1981). Lake Kivu includes several endemic species of fish, which reflects its ecological diversity, its period of isolation, and its past and present connections with other Rift

*Corresponding author. Email: [email protected]

ISSN 0022-2933 print/ISSN 1464-5262 online © 2011 Taylor & Francis DOI: 10.1080/00222933.2011.562618 http://www.informaworld.com 1836 N. Cumberlidge and K.S. Meyer

Table 1. Comparison of species richness and in the freshwater crab faunas of the .

Lake River basin Surface area Elevation No. of freshwater No. of endemic (km2) (m asl) crab species species

Kyoga 1720 914 0∗ 0 Victoria White Nile 68 800 1134 2∗ 0 Albert White Nile 5300 615 0∗ 0 Edward White Nile 2325 912 0∗ 0 Kivu Congo 2700 1460 4† 2 Tanganyika Congo 32 900 773 10‡ 10 Congo 5760 800 1∗ 0 Lake Mweru Congo 5120 917 1∗ 0 29 600 500 1∗ 0

Notes: ∗Unpublished data; †present study; ‡Cumberlidge et al. 1999 and Marijnissen et al. 2004.

Valley lakes. However, in comparison with Lakes Victoria, Tanganyika and Malawi, the fish fauna of Lake Kivu is quite limited, with only about 35 species of fish, most of which are native to the lake (Coulter 1991). While the fish and zooplank- ton of Kivu have been relatively well studied (Beadle 1981; Dumont 1986; Snoeks et al. 1997; Kaningini et al. 2003; Isumbisho et al. 2006), little work has been done on the lake’s freshwater crabs, despite their economic, ecological and evolutionary importance (Cumberlidge et al. 2009). The fish fauna of Lake Kivu has affinities with that of Lake Edward and the Nile River basin (reflecting its ancient connections), and with that of Lakes Victoria and Tanganyika, but the affinities of Kivu’s freshwater crab fauna have been largely undoc- umented because of a lack of collection efforts coupled with longstanding taxonomic uncertainties (Bott 1955). We can, however, state that Potamonautes lirrangensis is found in the Rift Valley lakes south to , and west into the , and Potamonautes mutandensis is found east as far as in the Nile basin, while Potamonautes idjwiensis and Potamonautes bourgaultae are found only in Kivu. The number of species of Potamonautes MacLeay, 1838, in the lake varies accord- Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 ing to taxonomic authority: either two species (Bott 1955) or four species (Chace 1942; present work). Here we agree with Chace (1942) that P. lirrangensis (Rathbun, 1904) and P. idjwiensis (Chace, 1942), both from Idjwi Island, are present in Lake Kivu, and we add two other species, P. mutandensis and P. bourgaultae sp. nov., previously not known to occur in the lake. We differ from Chace (1942) in that we do not recog- nize Potamonautes berardi and Potamonautes emini as being present in Lake Kivu. We also disagree with Bott (1955), who treated P. idjwiensis from Lake Kivu as a junior synonym of Potamonautes (Rotundopotamonautes) granviki Colosi, 1924. Later authors (Cumberlidge 1997, 1998; Ng et al. 2008; Cumberlidge et al. 2009) recognized P. idjwiensis as a valid species and considered P. (G.) granviki to be a junior synonym of Potamonautes loveni Colosi, 1924 (Williams 1991; Cumberlidge and Clark 2010). It is this opinion which is held here. The third species of freshwater crab from Lake Kivu recognized here is P. mutandensis (Chace, 1942), which was treated by Bott (1955) as a junior synonym of the northern Tanzanian species P. emini (Hilgendorf, 1892) (Reed and Cumberlidge Journal of Natural History 1837

2006). Before the present work P. mutandensis was known only from Lake Mutanda, a volcanic crater lake in Kigezi Province in southern Uganda, about 140 km northeast of Lake Kivu. Here we report on a number of new records of P. mutandensis that extend the range of this species from a narrowly distributed small lake endemic to a more widespread species with a distribution that now includes Lake Kivu in the Democratic Republic of Congo and Lakes Bunyonyi and Mutanda in Uganda. In addition, we describe here a fourth species from Lake Kivu, P. bourgaultae, sp. nov., which is the third species from Idjwi Island. The growing interest in the biological and other commercially exploitable resources of Lake Kivu has increased the need for a revision of its freshwater crab fauna. It is important to be able to make precise identifications of African freshwater crabs, not only because some of the larger species found in Lake Kivu (e.g. P. lirrangensis) support small commercial fisheries, but also because crabs are preyed upon by commercially important species of fish. However, at present it is dif- ficult for the non-specialist to distinguish between the species of Potamonautes from Lake Kivu because the identification keys of Chace (1942) and Bott (1955) are out of date and do not include all the described species, and no modern taxonomic treat- ments are available. The present work therefore aims to revise the taxonomy of the freshwater crabs of Lake Kivu by focusing on important taxonomic characters such as the gonopods, mouthparts, pereiopods and sternum (Cumberlidge 1999). The present work takes into account the modernization of the discipline, updates the identification keys to species, and compares the freshwater crab fauna of Lake Kivu with those of the other African great lakes. Specimens are deposited in the Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA (MCZ), the United States National Museum, Washington, D.C., USA (USNM), Northern Michigan University, Marquette, MI, USA (NMU), and the Natural History Museum, London, UK (NHM). All mea- surements were made with digital callipers, and are given in millimetres. Carapace width (CW) is the distance across the carapace at the widest point; carapace length (CL) is measured along the median line, from the anterior to the posterior mar- gin; carapace height (CH) is the maximum height of the cephalothorax from the highest point of the gastric region to the suture between thoracic sternites s2 and s3; front width (FW) is measured along the anterior frontal margin between the Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 base of the orbits. Photographs were taken with a digital camera in combination with a Leiz MZ 95 adapter, post processing was done using ADOBE PHOTOSHOP 7.0. Abbreviations used: s, thoracic sternite; s4/s5, s5/s6, s6/s7, s7/s8, sternal sulci between respectively numbered thoracic sternites; e, thoracic episternite; s4/e4, s5/e5, s6/e6, s7/e7, episternal sulci between respective thoracic sternites and episternites; a1– a6, abdominal somites 1–6; a5/a6, suture between adjacent abdominal somites; a7, telson of abdomen; GO1, first gonopod; GO2, second gonopod; asl, above sea level. The terminology is adapted from Cumberlidge (1999).

Taxonomy

Family POTAMONAUTIDAE Bott, 1970 Potamonautes MacLeay, 1838 Potamonautes idjwiensis (Chace, 1942) (Figures 1, 2, Table 2) 1838 N. Cumberlidge and K.S. Meyer

Potamon idjwiensis Chace 1942, p. 197–200, figs. 6,7. Potamonautes idjwiensis: Ng et al. 2008: 171; Cumberlidge et al. 2009: Appendix 1.

Material examined Type material. Democratic Republic of Congo. Holotype. Adult male (CW 37.1, CL 24.9, CH 14.5, FW 10.2) Idjwi Island, Lake Kivu coll. A. Loveridge, February 1939 (MCZ 11234); paratypes, 89 males, 106 females (11 ovigerous, 1 with hatchlings) Idjwi Island, Lake Kivu coll. A. Loveridge, February 1939 (MCZ 11235).

Other material. Two juvenile males (CW 22.9, CL 16.3, CH 9.3, FW 6.9; CW 21.0, CL 15.1, CH 8.1, FW 6.6) Lake Kivu, coll. Gillet, Bredin Expedition, 20 May 1955, (USNM 98923); adult male (CW 36.2, CL 24.8, CH 14.0, FW 9.1) near Bukavu, Lake Kivu, coll. W. L. Schmitt, Bredin Expedition, 1955 (USNM 98924A); adult female (CW 33.8, CL 22.4, CH 12.9, FW 9.3) near Bukavu, Lake Kivu, coll. W. L. Schmitt, Bredin Expedition, 1955 (USNM 98924B).

Diagnosis Carapace highly arched (CH/FW 1.42), surface smooth; postfrontal crest faint, almost absent; third maxilliped with faint vertical groove (Figure 1A,B); ventral mar- gins of merus of pereiopod 1 weakly granulated; distal meral tooth low, blunt; first carpal tooth low, blunt, followed by small granules (Figure 1A,C); sternal sulcus s2/s3 deep, completely crossing sternum; s3/s4 deep, meeting top of sternoabdominal cavity; telson of male abdomen with concave sides (Figure 1C); subterminal article of GO1 with strongly setose margins; distal margin of subterminal segment highest on medial side, forming pronounced shoulder, lowest on lateral side; terminal article of GO1 straight, slimmer than subterminal article, curving only slightly outward; GO2 terminal article straight, flagellum-like (Figure 2A–C).

Distribution Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 Bukavu and Idjwi Island, Lake Kivu, Democratic Republic of Congo.

Conservation status Potamonautes idjwiensis was assessed as Endangered (EN) using the IUCN Red List criteria (IUCN 2003; Cumberlidge et al. 2009, Appendix 1) (where it is incorrectly spelled as P. idjiwiensis) because it is restricted to two localities from Lake Kivu and therefore has a restricted area of occupancy. No new specimens have been collected since 1942, suggesting that the population may be in decline (Cumberlidge 2008a).

Remarks This revised diagnosis is intended to update the original description of this species by Chace (1942). Bott (1955) considered P. idjwiensis to be a junior synonym of P. (G.) granviki (Colosi 1924) but that opinion was not accepted by later authors Journal of Natural History 1839 idjwiensis mutandensis lirrangensis bourgaultae Potamonautes Potamonautes Potamonautes Potamonautes Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 e7): faint faint deep faint / FW): high (1.42) medium (1.22) medium (1.25) high (1.40) / e4–s7 / s4: complete incomplete incomplete incomplete / STS GO1 shoulder: prominent lacking lacking prominent / Distal meral tooth P1:First carpal tooth:Second carpal tooth:Terminal article GO1:GO1 STS margins:TA low, bluntGO1 dors. memb. margin: low, blunt granule straight spine diagonal setose low, blunt granule curved diagonal spine setose large spine small spine curved diagonal small, pointed setose granule granule straight U-shaped not setose Episternal sulci (s4 Table 2. Comparison of morphological characters of the freshwater crabsCharacter of Lake Kivu. Adult size range (CW, mm):Carapace height (CH Postfrontal crest:Cervical grooves:Carapace post. grooves 30.8 – 38.5Carapace AL marginCarapace sidewalls:Exorbital tooth:Epibranchial toothSternal incomplete sulcus present 21 s3 – 25 short smooth smooth incomplete deep small, lacking low 45 – 65 long, smooth faint complete, distinct smooth small, lowNotes: distinct AL, only lacking anterolateral at margin edges long, ofdors. deep memb., faint carapace; dorsal TA, membrane terminal of toothed GO1 articleSee in text of dorsal for GO1; view. other STS, abbreviations. subterminal granulated segment of 18 – GO1; large, 20 pointed P1, cheliped; small spine short smooth small, carinae, absent low granules lacking 1840 N. Cumberlidge and K.S. Meyer Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Figure 1. Potamonautes idjwiensis (Chace, 1942). (A) Dorsal view; (B) frontal view; (C) sternal view; (D) right cheliped, frontal view. Adult male (USNM 98923), CW 36.2. Journal of Natural History 1841

Figure 2. Potamonautes idjwiensis (Chace, 1942). (A) GO1, ventral view; (B) GO1, dorsal view; (C) GO2, ventral view. Adult male (USNM 98923), length of the terminal article measured along the mid-line of the dorsal face from tip to dorsal membrane 2.5 mm.

(Ng et al. 2008; Cumberlidge and Clark 2010) who considered P. idjwiensis to be a valid species. Potamonautes idjwiensis can be distinguished from P. l ove n i as follows. The postfrontal crest is absent in P. idjwiensis but faint and incomplete in P. l ove n i ; sternal sulcus s3/s4 is deep and complete and meets the top of the sternoabdominal cavity in P. idjwiensis, but is deep at the sides and missing in the middle in P. l ove n i ; the dactylus of the major cheliped in P. idjwiensis is only slightly arched and bears several small teeth, whereas in P. l ove n i the dactylus is highly arched and lacks denti- tion; finally, the terminal article of GO1 curves slightly upward in P. idjwiensis but is straight-sided and tapers evenly to a tip in P. loveni. Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Potamonautes mutandensis (Chace, 1942) (Figures 3–5, Table 2)

Potamon mutandensis Chace 1942: 194–197, fig. 4, 5a–g. Potamonautes mutandensis: Ng et al. 2008: 171; Cumberlidge et al. 2009: Appendix 1.

Material examined Type material. Uganda. Holotype: adult male (CW 25.7, CL 19.1, CH 9.5, FW 7.8), Mushongero, Lake Mutanda, , coll. A. Loveridge, 1 February 1939 (MCZ 11232). Paratype: Mushongero, Lake Mutanda, Kigezi District, coll. A. Loveridge, 1 February 1939 (MCZ 11233); four adult males (CWs 22.5, 20.8, 20.5, 19.6), two adult females (CWs 25.1, 21.3) , Kigezi District, from 1842 N. Cumberlidge and K.S. Meyer

outflowing stream 100 m from the lake in the outflow stream, coll. R. H. Lowe, 21 November 1952 (NHM 2010.214–219).

Other material. Democratic Republic of Congo. Adult male (CW 21.6, CL 15.0, CH 7.4, FW 5.7) plus a number of incomplete specimens with detached legs, Lake Kivu, 12 December 1917, coll. Robin Kemp (NHM 1917.12.12 6–25).

Diagnosis Carapace narrow (CW/CL 1.3), medium height (CH/FW 1.22); surface smooth; post- frontal crest faint to absent; epibranchial tooth absent; exorbital tooth low; cervical grooves faint, very long; third maxilliped with faint vertical groove (Figure 3A,B); first carpal tooth low, blunt, followed by two or three granules; distal meral tooth dis- tinct, pointed (Figure 3A,C); sternal sulcus s2/s3 deep, running horizontally across sternum; sulcus s3/s4 incomplete, deep on sides but missing in middle (Figure 3C); terminal article of GO1 turned strongly outward; distal margin of subterminal segment highest on medial side, forming pronounced shoulder, lowest on lateral side; margins of subterminal segment of GO1 with long setae (Figure 4A–C).

Distribution Lake Mutanda and Lake Bunyonyi in Uganda, and Lake Kivu in the Democratic Republic of Congo. The type locality label reads Mushongero (1◦1043 S, 29◦4058 E, 1888 m asl), which is on the road close to the northeast shoreline of Lake Mutanda (Figure 5).

Conservation status Potamonautes mutandensis was assessed as Endangered (EN) using the IUCN Red List criteria (IUCN 2003; Cumberlidge et al. 2009, appendix) because of its limited range and vulnerability to invasive crayfish. However, the present study shows that Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 this species is more widespread than previously thought, and that this species occurs over a wide range (Figure 5). The conservation status of P. mutandensis (Cumberlidge 2008b) therefore needs to be reassessed in the light of the new records presented here.

Remarks This revised diagnosis is intended to update the original description of this species by Chace (1942). Bott (1955) considered P. mutandensis to be a junior synonym of P. emini (Hilgendorf, 1892) from . Reed and Cumberlidge (2006) provided a redescription of P. emini, plus photographs, illustrations and a distribution map of the species. Potamonautes mutandensis can be distinguished from P. emini by the follow- ing characters: the dactylus of the major cheliped of P. mutandensis is highly arched, whereas that of P. emini is only slightly arched; the superior margin of the carpus of the cheliped of P. mutandensis has only faint carinae, whereas these carinae are strong in P. emini; episternal sulci s4/e4, s5/e5, s6/e6, s7/e7 are incomplete but still visible in Journal of Natural History 1843 Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Figure 3. Potamonautes mutandensis (Chace, 1942). (A) Dorsal view; (B) frontal view; (C) sternal view. Adult male (NHM 1917.12.12 6–25), CW 21.6. 1844 N. Cumberlidge and K.S. Meyer

Figure 4. Potamonautes mutandensis (Chace, 1942). (A) GO1, ventral view; (B) GO1, dorsal view; (C) GO2, ventral view. Adult male (NHM 1917.12.12 6–25), length of the terminal article measured along the mid-line of the dorsal face from tip to dorsal membrane 1.7 mm. Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Figure 5. Distribution of Potamonautes mutandensis. Star, type locality; black circles, other localities. Scale bar 70 km. Journal of Natural History 1845

P. mutandensis but absent and smooth in P. emini; the distal margin of the subterminal segment of GO1 at the dorsal membrane is diagonal in P. mutandensis but U-shaped in P. emini; and the medial and lateral margins of the dorsal membrane of GO1 are of subequal width in P. mutandensis, whereas the lateral margin is longer than the medial margin in P. emini; finally, the medial and lateral folds of the terminal article of GO1 are even in P. mutandensis, whereas the lateral fold is higher than the medial fold in P. emini.

Potamonautes lirrangensis (Rathbun, 1904) (Figures 6–8, Table 2)

Potamon (Potamonautes) lirrangensis Rathbun 1904, pl. 14, fig. 8; Rathbun 1905: 169; 1921: 413–415, pl. 25,26, fig. 3, 8; Balss 1914: 404; 1929: 374–348; Chace 1942: 188– 189, fig. 1. Potamon (Potamonautes) orbitospinus Cunnington 1907: 250–251, pl. 16, fig. 1. Potamonautes orbitospinus: Balss 1929: 439, 1936: fig. 18. Potamonautes lirrangensis: Balss 1936: 188–189, fig. 24. Potamon orbitospinus: Chace 1942: 218. Potamonautes (Lirrangopotamonautes) lirrangensis: Bott 1955: 268–270, pl. 26, fig. 2a–d, 38, 39, 83. Potamonautes lirrangensis: Reed and Cumberlidge 2006: 23–25, pl. 5a–d, fig. 41–51, 153–154, 177; Ng et al. 2008: 171.

Material examined Democratic Republic of Congo. Subadult male, Idjwi Island, Lake Kivu, February 1939, coll. A. Loveridge (MCZ 11224). Rwanda. Juvenile male (CW 30.0, CL 23.7, CH 11.2, 9.8) Lake Kivu at Gisenye, March 1936, coll. J. C. Bequaert (MCZ 9177). Malawi. Adult male (CW 46.5, CL 33.5, CH 12.8, FW 10.2) 7.2 km east-northeast of Monkey Bay, Lake Malawi, 23 May 1968, coll. D. H. Eades (NMU TRW 1972.05). Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Type locality Lirranga, at the junction of the Congo and Ubangi Rivers, Democratic Republic of Congo.

Diagnosis Carapace medium height (CH/FW 1.25); postfrontal crest distinct, complete; grooves on posterior part of carapace deep; exorbital tooth large, forward pointing spine; epibranchial tooth small spine; anterolateral margin behind epibranchial tooth curv- ing strongly outward, then curving inward over posterolateral margin, lined by either granules or small teeth (Figure 6A); vertical sulcus on ischium of third maxilliped faint to absent; suborbital, subhepatic regions of carapace sidewall with granules; subor- bital margin and horizontal sulcus of carapace sidewall both granulated (Figure 6B); first carpal tooth on carpus of cheliped large, sharp spine; second carpal tooth small 1846 N. Cumberlidge and K.S. Meyer Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Figure 6. Potamonautes lirrangensis (Rathbun, 1904). (A) Dorsal view; (B) frontal view; (C) sternal view. Adult male (NMU TRW 1972.05), CW 46.5 mm. Journal of Natural History 1847

Figure 7. Potamonautes lirrangensis (Rathbun, 1904). (A) GO1, ventral view; (B) GO1, dorsal view; (C) GO2, ventral view. Adult male (NMU TRW 1972.05), length of the terminal article measured along the mid-line of the dorsal face from tip to dorsal membrane 3.7 mm.

spine, smaller than first tooth; ventral margins of merus of pereiopod 1 both heavily granulated; distal meral tooth sharp spine (Figure 6A,C).

Distribution Lake Kivu, Democratic Republic of Congo and Rwanda, in Tanzania, and Lake Malawi in Malawi (Figure 8). Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 Conservation status Potamonautes lirrangensis was assessed as Least Concern (LC) using the IUCN Red List criteria (IUCN 2003; Cumberlidge et al. 2009, appendix) because it has a wide distribution, has been caught recently from a number of different localities, is well represented in museum collections, and has no known threats (Cumberlidge 2008c).

Remarks A number of previous authors (Cunnington 1907; Balss 1929, 1936) have reported on the presence of P. lirrangensis in Lake Kivu (as Potamon orbitospinus), and Chace (1942) illustrated the carapace and GO1 of the specimen of P. lirrangensis from the lake (MCZ 11224). However, Bott (1955) was the first to consider Potamonautes lir- rangensis to be the valid name for the species also described as Potamon orbitospinus Cunnington, 1907, with P. lirrangensis being the senior synonym. Reed and 1848 N. Cumberlidge and K.S. Meyer

Figure 8. Distribution of Potamonautes lirrangensis. Star, type locality; black circles, other localities. Scale bar 508 km.

Cumberlidge (2006) upheld this opinion and provided a redescription, photographs and illustrations of taxonomically important characters for P. lirrangensis,aswellasa detailed distribution map for the species, but they did not include any localities from Lake Kivu. Another taxon, Potamonautes (Lirrangopotamonautes) lirrangensis ade- leae Bott, 1968, from the Democratic Republic of Congo near the Angolan border, was originally described as a subspecies of Potamonautes (Lirrangopotamonautes) lir- rangensis, but was later recognized as the separate species P. adeleae Bott, 1968, by

Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 Cumberlidge and Tavares (2006) and Ng et al. (2008). The type locality of P. lirrangen- sis is Lirranga on the Congo River in the Democratic Republic of Congo, and its range includes the Upper Congo River in Central Africa and a number of localities along the Rift Valley in Lakes Kivu, Tanganyika and Malawi (Reed and Cumberlidge 2006).

Potamonautes bourgaultae,sp.nov. (Figures 9–12, Table 2)

Potamon emini: Chace 1942: 197, fig. 7 (not Telphusa emini Hilgendorf, 1892) Potamon berardi: Chace 1942: 207 (not Telphusa berardi Audouin, 1825)

Type locality Idjwi Island, Lake Kivu, Democratic Republic of Congo. Journal of Natural History 1849

Type material Democratic Republic of Congo. Holotype. Subadult male (CW 17.3, CL 11.0, CH 6.5, FW 4.8) Idjwi Island, Lake Kivu, February 1939, coll. A. Loveridge (MCZ 11231) (Potamon emini of Chace 1942); subadult female (CW 17.3, CL 12.5, CH 7.3, FW 4.9) Idjwi Island, Lake Kivu, February 1939, coll. A. Loveridge (MCZ 11231) (Potamon emini of Chace 1942); subadult female (CW 17.3, CL 12.6, CH 6.4, FW 4.7) Idjwi Island, Lake Kivu, February 1939, coll. A. Loveridge (MCZ 11230) (Potamon berardi of Chace 1942).

Diagnosis Carapace surface smooth; highly arched (CH/FW 1.4); postfrontal crest incomplete, strongest at lateral edges (Figure 9A,B, 11A,B); ischium of third maxilliped with faint vertical groove (Figures 9B, 11I); sternal sulcus s3/s4 incomplete, deep at sides but missing in middle (Figure 11E); distal meral tooth reduced to large granule; first carpal tooth small, pointed; second carpal tooth reduced to granule, followed by several other granules (Figures 9A,C; 11C,D); dactylus of major cheliped lined by alternat- ing large and small teeth; fixed finger of propodus of major cheliped lined by low, rounded teeth, first of two large teeth in line with large tooth on dactylus (Figures 9B, 11G,H); distal margin of GO1 subterminal segment highest on medial side, forming pronounced shoulder; terminal article of GO1 slim, straight, tapering evenly to tip, curving slightly outward (Figures 10A,D, 12A,D); lateral, medial folds of GO1 ter- minal article low, even; dorsal membrane broad, widest at lateral edge, narrowest at medial edge, proximal margin U-shaped (Figures 10B,D, 12B,E).

Description Based on holotype, subadult male (CW 17.3). Carapace moderately wide (CW/FW 3.6), high (CH/FW 1.4); surface texture completely smooth; front strongly deflexed, relatively narrow (FW/CW 0.28); postfrontal crest incomplete, strongest at lateral edges, gap between postorbital crests and epigastric crests; mid-groove between epigastric crests faint (Figures 9A, 11A); epibranchial, exorbital teeth low/absent; Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 suborbital margin smooth; anterolateral margin completely smooth, continuous with smooth posterolateral margin; cardiac groove faint to absent, semicircular, urogastric grooves faint, transverse branchial, cervical grooves absent (Figures 9A,B, 11A,B); sidewalls completely smooth with distinct longitudinal suture; vertical suture on cara- pace sidewall faint, not meeting anterolateral margin (Figures 9B, 11B). Mandibular palp with simple setose terminal segment; epistomial tooth triangular, margins granu- lated; third maxilliped exopod with long flagellum; third maxilliped ischium with faint vertical groove (Figures 9B, 11I). Sternal sulcus s1/s2 short, very faint; s2/s3 faint, complete; s3/s4 incomplete, deep at sides but missing in middle; episternal sulci faint (Figures 9C, 11E); abdomen slim, triangular, tapered, widest at base; telson outline triangular with rounded apex and slightly concave sides (Figure 9C, 11F); s6/s7 meeting abdomen at a5/a6. Distal margin of GO1 subterminal article lowest on lateral side, highest on medial side, forming pronounced shoulder; GO1 terminal article slim, directed straight upward, tapering evenly to tip (Figures 10A,C, 12A,D); lateral and medial folds of 1850 N. Cumberlidge and K.S. Meyer Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Figure 9. Potamonautes bourgaultae, sp. nov. (A) Dorsal view; (B) frontal view; (C) sternal view. Holotype subadult male (MCZ 11231), CW 17.3 mm. Journal of Natural History 1851

Figure 10. Potamonautes bourgaultae, sp. nov. (A) GO1, ventral view; (B) GO1, dorsal view; (C) detail of GO1 tip, ventral view; (D) detail of GO1 tip, dorsal view; (E) GO2. Holotype subadult male (MCZ 11231), length of terminal article measured along the mid-line of the dorsal face from tip to dorsal membrane 1.4 mm.

GO1 terminal article low, even; groove on terminal article not visible on dorsal face; dorsal membrane broad, widest at lateral edge, narrowest at medial edge, proximal margin U-shaped; junction between terminal and subterminal segments of GO1 vis- ible on ventral side (Figures 10A,C, 12A,D); GO2 terminal article long, straight, flagellum-like, about as long as subterminal segment (Figures 10E, 12C). Dactylus of major cheliped slightly arched, upper margin smooth, closed fin- gers enclosing long narrow interspace, lined by alternating large, small teeth; fixed finger of propodus of major cheliped with series of low, rounded teeth, plus two large teeth, first large tooth in line with large tooth on dactylus; lower margin of propodus slightly indented (Figures 9B, 11G,H); first carpal tooth small, pointed; second carpal tooth reduced to small granule, followed by other granules; dis- tal meral tooth reduced to large granule; outer face of merus smooth, superior margin with faint carinae; ventral margins of merus of cheliped with small granules (Figure 11C,D); ischium of cheliped smooth; walking legs p2–p5 slender, length nor- mal, neither elongated or shortened; dactyli of p2–p5 tapering to point, each bearing Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 four rows of downward-pointing short, sharp spines. Small species; holotype male (CW 17.8) almost adult (subadult); pubertal moult estimated to be between CW 18 and 20 mm.

Distribution This species is endemic to Idjwi Island (40 × 12 km, 275 km2), Lake Kivu, Democratic Republic of Congo.

Etymology This species is named in honour of the late Dr Louise M. Bourgault of Northern Michigan University, Marquette, MI, USA, in recognition of her outstanding contri- butions to the study of HIV-AIDS in Africa. 1852 N. Cumberlidge and K.S. Meyer Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011

Figure 11. Potamonautes bourgaultae, sp. nov. (A) Carapace, dorsal view; (B) carapace, frontal view; (C) carpus and merus of right pereiopod 1 (major cheliped), dorsal view; (D) carpus and merus of right pereiopod 1 (major cheliped), ventral view; (E) male sternum; (F) male abdomen; (G) major (right) cheliped; (H) minor (left) cheliped; (I) left third maxilliped. Scale bars 10 mm, A–H; 5 mm, I. Journal of Natural History 1853

Figure 12. Potamonautes bourgaultae, sp. nov. (A) GO1, ventral view; (B) GO1, dorsal view; (C) GO2; (D) detail of GO1 tip, ventral view; (E) detail of GO1 tip, dorsal view. Scale bars: 1 mm, A–C; 0.67 mm, D, E.

Remarks Potamonautes bourgaultae is similar to P. idjwiensis and P. mutandensis, which are also found in Lake Kivu. All of these are small or medium-sized crabs with a smooth untoothed carapace with a faint or absent postfrontal crest. However, P. bourgaultae can be easily distinguished from P. idjwiensis as follows. Potamonautes idjwiensis has a deep complete, sternal sulcus s3/s4, which meets the top of the sternoabdominal cav- ity, but s3/s4 is deep at the sides but missing in the middle in P. bourgaultae; and the dorsal membrane of GO1 of P. idjwiensis has equal lateral and medial margins with a diagonal proximal margin, whereas the medial margin is narrower, and the prox- imal margin is U-shaped in P. bourgaultae. Potamonautes bourgaultae can be easily distinguished from P. mutandensis as follows. The distal meral tooth is distinct and pointed in P. mutandensis but reduced to a large granule in P. bourgaultae; the grooves on the posterior carapace are deep in P. mutandensis but absent in P. bourgaultae;the Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 junction between the subterminal and terminal segments of GO1 lacks a shoulder in P. mutandensis but has a pronounced medial shoulder in P. bourgaultae; and the terminal article of GO1 curves strongly outward in P. mutandensis but is straight in P. bourgaultae. Chace (1942) assigned two specimens of P. bourgaultae to P. b e ra rd i and another specimen to P. emini, and indeed, P. bourgaultae is similar to these species in that all three have a smooth untoothed carapace. However, P. bourgaultae can be easily distinguished from P. b e ra rd i as follows. The ischium of the third maxilliped com- pletely lacks a groove in P. b e ra rd i but has a faint but distinct groove in P. bourgaultae; the ventral margins of the merus of the cheliped of P. b e ra rd i are lined with small, pointed teeth whereas these margins are lined by small granules in P. bourgaultae; the distal meral tooth is large and pointed in P. b e ra rd i but reduced to a large gran- ule in P. bourgaultae; and the first carpal tooth is small and pointed in P. b e ra rd i but small and rounded in P. bourgaultae. Potamonautes bourgaultae can be distinguished from P. emini by the postfrontal crest, which is distinct and complete in P. emini but 1854 N. Cumberlidge and K.S. Meyer

faint and incomplete in P. bourgaultae; by the distal meral tooth, which is large and surrounded by granules in P. emini but is isolated as a single granule in P. bourgaultae; by the junction between the subterminal and terminal segments of GO1, which lacks a shoulder in P. emini but has a pronounced medial shoulder in P. bourgaultae;andby the terminal article of GO1, which curves strongly outward in P. emini but is straight in P. bourgaultae.

Comparisons Of the four species of freshwater crabs found in Lake Kivu P. idjwiensis and P. mutandensis are the most similar. Both species have a medium body size, a smooth untoothed carapace, and a faint to absent postfrontal crest; both lack an epibranchial tooth; both have a faint groove on the ischium of the third maxilliped; both have a low and blunt first carpal tooth followed by granules; both have a complete ster- nal sulcus s2/s3, and both have faint episternal sulci. However, the two species can be easily distinguished by the following characters: the cervical groove is short in P. idjwiensis but long and faint in P. mutandensis; the distal meral tooth is low and blunt in P. idjwiensis but distinct and pointed in P. mutandensis; sternal sulcus s3/s4 is deep in P. idjwiensis, meeting the top of the sternoabdominal cavity, but incomplete, deep at the sides, and missing in the middle in P. mutandensis. The terminal article of gonopod 1 is straight with an upturned tip in P. idjwiensis, but curved strongly outward in P. mutandensis; the junction between the terminal article and the subter- minal article of gonopod 1 is visible on the ventral face in P. mutandensis but not in P. idjwiensis. Both P. idjwiensis and P. mutandensis are easily distinguished from P. lirrangensis, which is a large species with a large pointed exorbital tooth. The postfrontal crest is absent in both of the former species but distinct, complete and lined with small granules in P. lirrangensis; the exorbital and epibranchial teeth are both absent in P. idjwiensis and P. mutandensis, whereas the exorbital tooth is a large, forward pointing spine and the epibranchial tooth is a small spine in P. lirrangensis.The anterolateral margin, which is smooth in P. idjwiensis and P. mutandensis, is lined by either large granules or small teeth in P. lirrangensis; the carapace sidewalls are smooth in P. idjwiensis and P. mutandensis but are roughened by carinae and granules Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 in P. lirrangensis. The first carpal tooth in both P. idjwiensis and P. mutandensis is low and blunt, but a large pointed spine in P. lirrangensis. Finally, both P. idjwiensis and P. mutandensis are medium-sized species with an adult size range between CW 21–25 and CW 31–39 respectively, whereas P. lirrangensis is a large species with an adult size range between CW 45 and 65 (Table 2). A few characters are unique in each of these three species. For example, the distal meral tooth is low and blunt in P. idjwiensis, distinct and pointed in P. mutanden- sis and a sharp spine in P. lirrangensis. The terminal article of gonopod 1 is straight with an upturned tip in P. idjwiensis and curved strongly outward in P. mutanden- sis;inP. lirrangensis the first half is straight, the second half is bent strongly outward, tapering to a broad, upcurved tip. Sternal sulcus s3/s4 is complete and deep, reaching the top of the sternoabdominal cavity in P. idjwiensis, but incom- plete in both P. mutandensis and P. lirrangensis. Two characters are shared by all three species: a complete s2/s3 and a faint groove on the ischium of the third maxilliped. Journal of Natural History 1855

Biogeography Two genera of freshwater crabs (Potamonautes and ) are found in the African Great Lakes and both belong to the Potamonautidae, a family that is found throughout the African continent and which is endemic to the Afrotropical region (Daniels et al. 2006; Cumberlidge et al. 2008; Yeo et al. 2008; Cumberlidge 2009). Of these genera, Potamonautes is widespread and is found throughout sub- Saharan Africa and the Nile River basin, while Platythelphusa is endemic to Lake Tanganyika (Cumberlidge et al. 1999; Marijnissen et al. 2004). Lakes Kivu (with two endemic species of Potamonautes) and Tanganyika (with nine endemic species of Platythelphusa and one endemic species of Potamonautes) are the only two African lakes that have endemic species of freshwater crabs (Table 1). Lake Kivu has one species (P. mutandensis) that also occurs in the Nile catchment, one species (P. lirrangensis) that occurs in the Congo basin (Rwanda and Democratic Republic of Congo), and two species (P. idjwiensis and P. bourgaultae) that are endemic to the lake (Table 2). Lake Kivu shares no species with Lakes Edward and Albert, and one (P. lir- rangensis) with Lake Tanganyika’s tributaries. While freshwater crabs are represented in the other African lakes, species richness overall is low and none are lake endemics. For example, even the two largest lakes – Lake Victoria (two species of Potamonautes) and Lake Malawi (one species of Potamonautes) – lack endemic crabs and are species poor (Table 1). The generally low faunal richness and endemism rates of freshwater crabs in the African lakes contrast sharply with the impressive species richness and endemism seen in the fish in these lakes (Beadle 1981).

Key to the species of Potamonautes from Lake Kivu 1. Postfrontal crest distinct, complete; anterolateral margin with either small teeth or large granules; exorbital tooth large, forward pointing spine; epi- branchial tooth small spine; first carpal tooth large, sharp spine ...... P. lirrangensis Postfrontal crest faint to absent, incomplete; anterolateral margin smooth; exorbital, epibranchial teeth low or absent; first carpal tooth low ...... 2

Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 2. Sternal sulcus s3/s4 complete, meeting top of sternoabdominal cavity; telson sidesstronglyconcave...... P. idjwiensis Sternal sulcus s3/s4 missing in middle, not meeting top of sternoabdominal cavity;telsonsidesslightlyconcaveorstraight...... 3 3. Distal meral tooth distinct, pointed; distal margin of GO1 low, lacking shoul- der; dorsal membrane of GO1 broad, lateral and medial margins equal, proximal margin straight; GO1 terminal article evenly curved strongly outward ...... P. mutandensis Distal meral tooth granular; distal margin of GO1 highest medially, forming pronounced shoulder; medial margin of dorsal membrane of GO1 nar- rower than lateral margin, proximal margin U-shaped; GO1 terminal article straight,taperingevenlytotip...... P. bourgaultae 1856 N. Cumberlidge and K.S. Meyer

Acknowledgements Paul F. Clark and Miranda Lowe (NHM) are thanked for loaning specimens and for their sup- port and warm hospitality during a series of visits to the museum, and Dr Rafael Lemaitre and Marilyn Schotte (USNM) are thanked for their support during work by the first author on the USNM collection. Furthermore, Ardis Johnson and Adam Baldinger (MCZ) are thanked for their assistance and kind hospitality during visits by the first author to that museum. Erica M. Hattis (NMU Freshman Fellows Program) is thanked for her contributions to ear- lier versions of parts of this work. We would also like to acknowledge support from the NMU Peter White Scholar Award (N.C.) and the NMU University Scholars Research Grant Program (K.S.M.).

References Balss H. 1914. Decapode Crustaceen von den Guinea-Inseln, Sud-Kamerun und dem Congogebiet. Ergebnisse der zweiten Deutscher Zentral-Africa-Expedition 1910–1911, 1 (Zool.): 97–108, Abb. 1–12. Balss H. 1929. Über Ostafrikanischer Potamonidae (Decapoda). Zool Jb. 58:339–358. Balss H. 1936. Beiträge zur Kenntnis der Potamonidae (Süâwasserkrabben) des Kongogebietes. Rev Zool Bot Afric, 28(2):195–204. Beadle LC. 1981. Volcanic-barrier lakes: Lake Kivu. The inland waters of tropical Africa. 2nd edition. London and New York: Longman House. pp.267–275. Bott R. 1955. Die Süβwasserkrabben von Afrika und ihre Stammesgeschichte. Ann Mus Congo belge (C, 3, 3) 1 (3): 209–352, Taf. 1–30, Abb. 1–103. Bott R. 1970. Betrachtungen über die Entwicklungsgeschichte und Verbreitung der Süßwasser- Krabben nach der Sammlung des Naturhistorischen Museums in Genf/Schweiz. Rev suisse Zool. 77(2):327–344. Chace FA. 1942. Scientific results of a fourth expedition to forested areas in eastern Africa, III: Decapod Crustacea. Bull Mus Comp Zool Harvard College 91(3):185–233, Abb. 1–10. Coulter GW. 1991. Lake Tanganyika and its life. New York: Oxford University Press. Cumberlidge N. 1997. The African and Madagascan freshwater crabs in the Museum of Natural History, Vienna (Crustacea: Decapoda: Brachyura: Potamoidea). Ann naturh Mus Wien 99B:571–589. Cumberlidge N. 1998. The African and Madagascan freshwater crabs in the Zoologische Staatssammlung, Munich. Spixiana 21(3):193–214. Cumberlidge N. 1999. The Freshwater Crabs of , Family Potamonautidae. Faune et Flore tropicales 35. Paris: IRD. pp.1–382.

Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 Cumberlidge N. 2008a. Potamonautes idjiwiensis (sic). In: IUCN 2010. IUCN Red List of Threatened Species [Internet]. Version 2010.2. [cited 2010 July 30]. Available from: www.iucnredlist.org. Cumberlidge, N. 2008b. Potamonautes mutandensis. In: IUCN 2010. IUCN Red List of Threatened Species [Internet]. Version 2010.2. [cited 2010 July 30]. Available from: www.iucnredlist.org. Cumberlidge, N. 2008c. Potamonautes lirrangensis. In: IUCN 2010. IUCN Red List of Threatened Species [Internet]. Version 2010.2. [cited 2010 July 30]. Available from: www.iucnredlist.org. Cumberlidge N. 2009. Chapter 27, Freshwater Crabs and Shrimps (Crustacea: Decapoda) of the Nile Basin. In Dumont HJ. editor. The Nile. Origin, Environments, Limnology and Human Use. Monographiae Biologicae, Vol. 89. New York: Springer. pp. 547–561. Cumberlidge N, Clark PF. 2010. A redescription of Potamonautes loveni (Colosi, 1924), a med- ically important freshwater crab from western Kenya and eastern Uganda, East Africa (Brachyura: Potamoidea: Potamonautidae). Studies on Brachyura: a homage to Danièle Guinot. Crustaceana Monogr. 11:61–74. Journal of Natural History 1857

Cumberlidge N, Ng PKL, Yeo DCJ, Magalhaes C, Campos MR, Alvarez F, Naruse T, Daniels SR, Esser LJ, Attipoe FYK, et al. 2009. Freshwater crabs and the biodiversity crisis: importance, threats, status, and conservation challenges. Biol Cons. 142(8):1665–1673. Cumberlidge N, Sternberg RV, Bills IR, Martin HA. 1999. A revision of the genus Platythelphusa A. Milne-Edwards, 1887 from Lake Tanganyika, East Africa (Decapoda: Potamoidea: Platythelphusidae). J Nat Hist. 33:1487–1512. Cumberlidge N, Sternberg Rv, Daniels SR. 2008. A revision of the higher taxonomy of the Afrotropical freshwater crabs (Decapoda: Brachyura) with a discussion of their biogeography. Biol J Linn Soc. 93:399–413. Cunnington W. 1907. Zoological Results of the Third Tanganyika Expedition, conducted by Dr. W.A. Cunnington, 1904–1905. Report of the Brachyurous Crustacea. Proc Zool Soc. 258–276, Taf. 16–17, Abb 84. Daniels SR, Cumberlidge N, Pérez-Losada M, Marijnissen SAE, Crandall, KA. 2006. Evolution of Afrotropical freshwater crab lineages obscured by morphological conver- gence. Mol Phylo Evol. 40:227–235. Dumont HJ. 1986. The Tanganyika Sardine in Lake Kivu – Another Ecodisaster for Africa. Environ Conserv. 13:143–148. Isumbisho M, Sarmento H, Kaningini B, Micha J-C, Descy J-P. 2006. of Lake Kivu, East Africa, half a century after the Tanganyika sardine introduction. J Plankton Res. 28:971–989. IUCN. 2003. Guidelines for Application of IUCN Red List Criteria at Regional Levels: ver- sion 3.0. IUCN Species Survival Commission. Gland, Switzerland and Cambridge, UK: IUCN. Kaningini M, Isumbisho M, Ndayike N, Micha, J.-Cl. 2003. Étude du zooplancton du lac Kivu: composition, variations d’abondance et distribution, Bull Séanc Acacd R Sci Outre-Mer. 49:145–160. Marijnissen SAE, Schram FR, Cumberlidge N, Michel E. 2004. Two new species of Platythelphusa A. Milne-Edwards, 1887 (Decapoda, Potamoidea, Platythelphusidae) and comments on the taxonomic position of P. denticulata Capart, 1952 from Lake Tanganyika, East Africa (Brachyura: Potamoidea: Potamonautidae, Platythelphusidae, Deckeniidae). Crustaceana 77:513–532. Ng PKL, Guinot D, Davie PJF. 2008. Systema Brachyurorum: Part 1. An annotated checklist of extant brachyuran crabs of the world. Raffles Bull Zool. 17:1–286. Rathbun M. 1904. Les Crabes d’Eau Douce (Potamonidae). Nouv Arch Mus Hist Nat. (4)6:225–312, Taf. 9–18, Abb. 1–37. Paris.

Downloaded By: [Cumberlidge, Neil] At: 01:23 16 June 2011 Rathbun M. 1905. Les Crabes d’Eau Douce (Potamonidae). Nouv Arch Mus Hist Nat. (4)7:159–322. Paris. Reed SK, Cumberlidge N. 2006. Taxonomy and biogeography of the freshwater crabs of Tanzania, East Africa. Zootaxa 1262:1–139. Snoeks J, De Vos L, van Den Audenaerde T. 1997. The ichthyogeography of Lake Kivu. S Afr J Sci. 93:579–584. Williams TR 1991, Freshwater crabs and Simulium neavei in East Africa. III. morphological variation in Potamonautes loveni (Decapoda: Potamidae). Trans R Soc Trop Med Hyg. 85:181–188. Yeo DCJ, Ng PKL, Cumberlidge N, Magalhães C, Daniels SR, Campos MR. 2008. A global assessment of freshwater crab diversity (Crustacea: Decapoda: Brachyura). In: Balian EV, Lévequè C, Segers H, Martens M. editors. Freshwater Diversity Assessment. Hydrobiologia 595:275–286.