Afrithelphusa Bott, 1969

Cumberlidge, Neil, Mvogo Ndongo, Pierre A., Clark, Paul F., Salieu, Sankoh & von Rintelen, Thomas, 2023, A revision of the West African freshwater crab genus Afrithelphusa Bott, 1969 (Brachyura: Deckeniidae: Deckeniinae) based on new morphological and genetic data, Journal of Natural History 57 (13 - 16), pp. 924-946 : 928-932

Afrithelphusa Bott, 1969

( Figures 1–8 ; Tables 1–3 )

Globonautes Bott, 1959: 997–999 ; 1969: 360; Monod 1977: 1209; 1980: 380; Cumberlidge 1987: 2210–2214.

Afrithelphusa Bott, 1969: 359 ; 1970: 25–27; Monod 1977: 1208–1210; 1980: 380; Cumberlidge 1996a: 684–688, table 1; 1996b: 814, 1999: 218–219; Ng et al. 2008: 169; Cumberlidge et al. 2008: 402, 405, 407–411, tables 1,2, fig. 2; Cumberlidge and Daniels 2022: 1276, 1279, 1299–1300, 1303, table 2.

Type species

Afrithelphusa gerhildae Bott, 1969 , by original designation, gender feminine.

Diagnosis

Carapace smooth, lacking visible granules, lateral carinae; carapace highly arched ( CH / FW = 1.4–1.8; Table 2 ); front medium width (CW/FW = 3.5–3.7) ( Figures 2 (a–d), 3(a–d), 4(a–c), 7(a,b,e,f); Table 2 ), postfrontal crest sharp-edged completely traversing carapace, meeting carapace lateral margins at epibranchial teeth,anterolateral margin lacking intermediate tooth between exorbital, epibranchial teeth ( Figures 2 (a–d), 3(a–d)). Vertical sulcus on carapace branchiostegite meeting anterolateral margin at epibranchial tooth ( Figure 4a–c ). Mandibular palp consisting of basis followed by two articles; terminal article (MPTA) distinctly bilobed (MPAL/MPTA = 0.5–0.7) ( Figure 4 (h–k); Table 3 ). Third maxilliped exopod lacking flagellum ( Figure 6 (m–p)); Cumberlidge 1999, fig. 49A). Cheliped carpus inner margin with large pointed distal tooth, small proximal tooth, followed by series of small teeth; cheliped merus inferior margins lined with small granules ( Figures 2 (a–d), 5(i–p), 7(a–d)).Sternal sulci Sl/ 2, S2/3, S3/4 deep, all completely crossing thoracic sternum; anterior margin of sterno-pleonal cavity terminating half-way along S4 ( Figure 4 (d–g)). G1TA medium length (G1TA/G1SA = 0.4), slim, broadest proximally, tapering to broad tip; medial, lateral folds on G1TA equal sized, low; G1TA-G1SA junction with clearly visible sulcus on ventral, dorsal sides ( Figure 6 (a,c,d,f,g,i,j,l). G2TA medium length,flagellum-like (G2TA/G2SA = 0.4–0.5) ( Figure 6 (b, e, h, k)).Maximum size up to 29.5 mm.

Distribution

Afrithelphusa is found only in the Upper Guinea forests of West Africa from Guinea to Sierra Leone ( Cumberlidge 1999); most species have a restricted distribution and are known only from a small type series or from a single locality ( Figure 1 ).

Species included

Afrithelphusa afzelii Colosi, 1924 , A. gerhildae Bott, 1969 , A. leonensis ( Cumberlidge, 1987) , and A. monodosa (Bott, 1959) .

Remarks

Afrithelphusa leonensis and A. monodosa were formerly assigned to Globonautes but were transferred to Afrithelphusa by Cumberlidge (1996a) in recognition of significant differences between these taxa and the type species, G. macropus , with respect to the gonopods and carapace ( Cumberlidge 1996a, 1996b, 1999; Cumberlidge and Daniels 2022). For example, the postfrontal crest of the four species of Afrithelphusa is sharp-edged and runs uninterrupted across the carapace ( Figures 1 (a–d), 2(a–d)); Cumberlidge 1999, fig. 46A–D), (vs postfrontal crest poorly defined and periodically interrupted in G. macropus ( Cumberlidge 1999, fig. 46E)), the G2TA of all four species of Afrithelphusa is a medium-length flagellum (G2TA/G2SA = 0.4– 0.5) ( Figure 6 (b,e,h,k)), (vs a G2TA that is extremely short and stub-like (G2TA/G2SA = 0.1) in G.macropus )( Table 3 ; Cumberlidge 1999,fig.53Z),and each of the four species of Afrithelphusa has a G1TA with a visible sulcus on the ventral and dorsal sides of the G1TA-G1SA junction ( Figure 6 (c,d,i,l)); Cumberlidge 1999, fig. 52AA, BB, CC, DD) (vs an obscured sulcus on the ventral side of the G1TA-G1SA junction in Globonautes ; Cumberlidge 1999, fig. 52EE).

Balss (1936, p. 200) and Bott (1955) questioned the validity of Sierra Leone as the collection locality of A. afzelii , and incorrectly speculated that this taxon was actually not even from Africa. This question was later resolved by Bott (1970) who included A. afzelii in Afrithelphusa , a genus he had earlier established (Bott 1969) for A. gerhildae from Guinea, West Africa. Cumberlidge (1996a, 1996b) subsequently added A. monodosa from Guinea and A. leonensis from Sierra Leone to this genus.

Cumberlidge and Daniels (2022) revised the higher classification of the Afrotropical freshwater crabs, recognising the family Deckeniidae with Globonautinae (for Afrithelphusa , Globonautes Bott, 1959 , Deckenia Hilgendorf, 1869 and Seychellum Ng, Stevcic and Pretzmann, 1995 ) and Hydrothelphusinae Bott 1955 (for all genera of Malagasy freshwater crabs). The Deckeniidae are reported from West Africa including Liberia, Guinea and Sierra Leone ( Afrithelphusa and Globonautes ), and East Africa including Tanzania, Kenya, Somalia ( Deckenia ), the granitic Seychelles ( Seychellum ) and Madagascar (12 endemic genera) ( Ng et al. 1995; Cumberlidge 1999; Reed and Cumberlidge 2006; Cumberlidge and Daniels 2022).

Figures

Figure 1. Distribution map of West Africa showing the known localities of all Afrithelphusa Bott, 1969 species in Guinea and Sierra Leone. Afrithelphusa afzelii (Colosi, 1924) (black triangle, not shown to scale); A. leonensis (Cumberlidge, 1987) (black circles, not shown to scale); A. monodosa (Bott, 1959) (black squares, not shown to scale); A. gerhildae Bott, 1969 (black diamond, not shown to scale). For exact localities see text. Scale bar = 111 km.

Figure 2. Afrithelphusa afzelii (Colosi 1924), adult ♂, CW 25.0 mm, ZMB Crust. 34,607, from Moyamba District, Sierra Leone: a, whole animal, dorsal view. Afrithelphusa gerhildae Bott, 1969, adult ♂ CW 22.5 mm, SMF 2619a, Le Voile de la Mariée, Kindia, Guinea: b, whole animal, dorsal view. Afrithelphusa leonensis (Cumberlidge, 1987), adult ♂, CW 26.4 mm, ZMB Crust. 34,606, from Guma Lake, Sugar Loaf Mountain, Sierra Leone: c, whole animal, dorsal view. Afrithelphusa monodosa (Bott, 1969), adult ♂, CW 24.3 mm, NMU 24.IV.2005, Sarabaya, Guinea: d, whole animal, dorsal view. Photographs a, c by PAMN; b by Michael Türkay; d by N. Cumberlidge and M. Lorenz. Scale bar: a = 17.2 mm; b = 15.5 mm; c = 18.9 mm; d = 15.7 mm. CW = carapace width, ZMB = Museum für Naturkunde, Berlin, Germany, SMF = Senckenberg Museum, Frankfurt, Germany, NMU = Northern Michigan University,USA,PAMN = Pierre Armand Mvogo Ndongo.

Figure 3. Afrithelphusa afzelii (Colosi 1924), adult ♂ CW 25.0 mm, ZMB Crust. 34,607, from Moyamba District,Sierra Leone: a, carapace,dorsal view. Afrithelphusa gerhildae Bott, 1969, adult ♂ CW 22.5 mm, SMF 2619a, Le Voile de la Mariée, Kindia, Guinea: b, carapace, dorsal view. Afrithelphusa leonensis (Cumberlidge, 1987), adult ♂, CW 26.4 mm, ZMB Crust. 34,606,from Guma Lake, Sugar Loaf Mountain, Sierra Leone: c, carapace, dorsal view. Afrithelphusa monodosa (Bott, 1969), adult ♂, CW 24.3 mm, NMU 24.IV.2005, Sarabaya,Guinea: d, carapace, dorsal view. Photographs a, c by P. A. Mvogo Ndongo; b by Michael Türkay; d by N. Cumberlidge and M. Lorenz. Scale bar: a = 7.8 mm, b = 7.1 mm, c = 8.3 mm, d = 7.6 mm. CW = carapace width, ZMB = Museum für Naturkunde, Berlin, Germany, SMF = Senckenberg Museum, Frankfurt, Germany, NMU = Northern Michigan University, USA.

Figure 4. Afrithelphusa afzelii (Colosi 1924), adult ♂ CW 25.0 mm, ZMB Crust. 34,607, from Moyamba District, Sierra Leone: a, carapace, frontal view; d, thoracic sternum, h, mandible frontal view. Afrithelphusa gerhildae Bott, 1969, adult ♂ CW 22.5 mm, SMF 2619a, Le Voile de la Mariée, Kindia, Guinea: e, thoracic sternum, i, mandible frontal view (Cumberlidge 1999, fig. 48A). Afrithelphusa leonensis (Cumberlidge, 1987), adult ♂, CW 26.4 mm, ZMB Crust. 34,606, from Guma Lake, Sugar Loaf Mountain, Sierra Leone: b, carapace, frontal view; f, thoracic sternum, j, mandible frontal view. Afrithelphusa monodosa (Bott, 1969), adult ♂, CW 24.3 mm, NMU 24.IV.2005, Sarabaya, Guinea: c, carapace,frontal view; g, thoracic sternum, k, mandible, frontal view. Photographs a, c by P. A. Mvogo Ndongo; d by Neil Cumberlidge and Margaret Lorenz; e by Michael Türkay. Scale bar: a = 8.9 mm; b = 9.6 mm; c = 11.6 mm; d–g = 8.0 mm; h–k = 3.1 mm. CW = carapace width, ZMB = Museum für Naturkunde, Berlin, Germany, NMU = Northern Michigan University, USA.

Figure 5. Afrithelphusa afzelii (Colosi 1924), adult ♂ CW 25.0 mm, ZMB 34607, from Moyamba District, Sierra Leone: a, right cheliped, frontal view;b, left cheliped, frontal view;i, right cheliped carpus superior view; m, right cheliped merus superior view. Afrithelphusa gerhildae Bott, 1969, adult ♂ CW 22.5 mm, SMF 2619a, Le Voile de la Mariée, Kindia, Guinea: c, right cheliped, frontal view (Cumberlidge 1999, fig. 50A); d, left cheliped, frontal view (Cumberlidge 1999, fig. 50A); j, right cheliped carpus superior view; n, right cheliped merus superior view. Afrithelphusa leonensis (Cumberlidge, 1987), adult ♂, CW 26.4 mm, ZMB Crust. 34,606, from Guma Lake, Sugar Loaf Mountain, Sierra Leone: e, right cheliped, frontal view; f, left cheliped, frontal view; k, right cheliped carpus superior view; o, right cheliped merus superior view. Afrithelphusa monodosa (Bott, 1969), adult ♂, CW 24.3 mm, NMU 24.IV.2005, Sarabaya, Guinea: g, right cheliped, frontal view; h, left cheliped, frontal view; l, right cheliped carpus superior view; p, right cheliped merus superior view. Photographs a, b, e, f, i, k, m, o by P. A. Mvogo Ndongo; g, h, l, p by Neil Cumberlidge and Margaret Lorenz; j, n by Michael Türkay. Scale bar: a–h = 11.2 mm; i–p = 5.6 mm. CW = carapace width, ZMB = Museum für Naturkunde, Berlin, Germany, SMF = Senckenberg Museum, Frankfurt, Germany, NMU = Northern Michigan University, USA.

Figure 6. Afrithelphusa afzelii (Colosi 1924), adult ♂ CW 29.5 mm, SMNH 168, Sierra Leone: a, G1 ventral view; b, G2 ventral view; c, G1 dorsal view; m, third maxilliped, frontal view. Afrithelphusa gerhildae Bott, 1969, adult ♂ CW 22.5 mm, SMF 2619a, Le Voile de la Mariée, Kindia, Guinea: d, G1 ventral view; e, G2 ventral view (Cumberlidge 1999, fig. 53AA); f, G1 dorsal view (Cumberlidge 1999, fig. 52B); n, third maxilliped, frontal view (Cumberlidge 1999, fig. 49A). Afrithelphusa leonensis (Cumberlidge, 1987), adult ♂, CW 26.4 mm, ZMB Crust. 34,606, from Guma Lake, Sugar Loaf Mountain, Sierra Leone: g, G1 ventral view; h, G2 ventral view; i, G1 dorsal view; o, third maxilliped, frontal view.Afrithelphusa monodosa (Bott, 1969), adult ♂, CW 24.3 mm, NMU 24.IV.2005, Sarabaya, Guinea: j, G1 ventral view; k, G2 ventral view; l, G1 dorsal view; p, third maxilliped,frontal view. Photographs a–c, g–i, m, o by P. A. Mvogo Ndongo; j–l, p by Neil Cumberlidge and Margaret Lorenz;d by Michael Türkay.Scale bar:a, c, d, f, g, i, j, l = 10.0 mm; b, e, h, k = 5.8 mm; m–p = 2.4 mm. CW = carapace width, SMNH = Swedish Museum of Natural History, Stockholm,Sweden,G1 = gonopod 1, G2 = gonopod 2, ZMB = Museum für Naturkunde,Berlin,Germany, SMF = Senckenberg Museum, Frankfurt, Germany, NMU = Northern Michigan University, USA.

Figure 7. Afrithelphusa afzelii (Colosi 1924), lectotype, adult ♂ CW 29.5 mm, SMNH 168, Sierra Leone: a, whole animal, dorsal view; c, whole animal, sternal view; e, carapace, frontal-dorsal view. Afrithelphusa leonensis (Cumberlidge, 1987), holotype, adult ♂, CW 26.4 mm, NHM 1955.10.7.42–43, Sugar Loaf Mountain, Sierra Leone: b, whole animal, dorsal view; d, whole animal, sternal view; f, carapace, frontal view. Photographs a, c, e by Neil Cumberlidge, b, d, f by Phillip Crabb (NHM). Scale bar: a, c = 19.7; b, d = 20.3 mm; e = 12.0 mm; f = 11.0 mm. CW = carapace width, SMNH = Swedish Museum of Natural History, Stockholm, Sweden, NHM = The Natural History Museum, London, UK.

Figure 8. Maximum likelihood (ML) tree topology of the four species of Afrithelphusa from West Africa based on mtDNA sequences corresponding to partial 16S rRNA and COI genes. Two outgroup taxa (Louisea edeaensis and Buea mundemba) are also shown. BI and ML statistical values on the nodes indicate posterior probabilities and bootstrap support, respectively. BI = Bayesian Inference.