Louisea balssi (Bott, 1959)

Mvogo Ndongo, Pierre A., von Rintelen, Thomas & Cumberlidge, Neil, 2019, Taxonomic revision of the endemic Cameroonian freshwater crab genus Louisea Cumberlidge, 1994 (Crustacea, Decapoda, Brachyura, Potamonautidae), with descriptions of two new species from Nkongsamba and Yabassi, ZooKeys 881, pp. 135-164 : 135

publication ID	https://dx.doi.org/10.3897/zookeys.881.36744
publication LSID	lsid:zoobank.org:pub:B058CA15-6A3D-41A1-9ADF-D00384234D8E
persistent identifier	https://treatment.plazi.org/id/710D45B5-BAE1-50C4-B497-98CDDBE05016
treatment provided by	ZooKeys by Pensoft
scientific name	Louisea balssi (Bott, 1959)
status

Treatment

Louisea balssi (Bott, 1959) Figs 2b View Figure 2 , 3b View Figure 3 , 4b View Figure 4 , 5b View Figure 5 , 6b View Figure 6 , 7b View Figure 7 , 8c, d View Figure 8 , 9b View Figure 9 , 10b View Figure 10 , 11b View Figure 11 , 12b View Figure 12 , 13b View Figure 13 , 14b View Figure 14 , 15b View Figure 15

Globonautes balssi Bott 1959: 999, fig. 7; Cumberlidge 1987: 2210; 1994: 127, figs 2 a, b, 3 ( j–l only), tables 1-2 (ZIM K 3506 only).

Globonautes macropus balssi Bott 1970: 25, pl. 1, figs 6-8.

Louisea balssi Cumberlidge 1999: 231, figs 53EE, 54-57, 62G, 68F, tables V, X–XIII, pl. 4 (not figs 46G, 48F, 49G, 52G, table IX); Ng et al. 2008: 169 (list); Mvogo Ndongo et al. 2018: 400.

Material examined.

CAMEROON. Holotype: juvenile male (CW 12.5 mm), Barombi Mbo [formerly Johann Albrechtshöhe (Government Station Johann Albrecht Mountain), Barombi Station] (4.666686N, 9.392042E), 323 m asl, 10 September 1909, coll. Carl Rathke (ZIM K3506). Paratypes: 3 adult females (CWs 22.0, 21.0, 21.0 mm) (ovigerous), subadult female (CW 13.5 mm), Barombi Mbo [formerly Johann Albrechtshöhe (Government Station Johann Albrecht Mountain), Barombi Station] (4.666686N, 9.392042E), 323 m asl, 10 September 1909, coll. Carl Rathke (SMF 5093, donated by ZIM K3506). Other material examined is given in Table 3 View Table .

Diagnosis.

Amended from Cumberlidge (1994, 1999); Mvogo Ndongo et al. (2018). Carapace smooth, urogastric groove faint; postfrontal crest faint, complete, meeting anterolateral margin behind intermediate tooth ( Fig. 3b View Figure 3 ); exorbital, intermediate teeth small, low, distinct ( Figs 4b View Figure 4 , 7b View Figure 7 ). Mandibular palp 2 segmented; terminal segment (TS) bilobed, with large distinct anterior lobe 0.5 × terminal segment length ( Fig. 15b View Figure 15 ). Third maxilliped ischium with distinct vertical groove ( Fig. 14b View Figure 14 ). Episternal sulci s4/e4, s5/e5, s6/e6 faint or missing, s7/e7 complete ( Fig. 5b View Figure 5 ). Major cheliped dactylus relatively slender, highly arched enclosing oval interspace when closed, with two large teeth (one proximal, one medial) ( Fig. 8b View Figure 8 ); propodus of major cheliped with two large proximal teeth, large medial tooth, small distal tooth ( Fig. 8b View Figure 8 ); cheliped carpus inner margin with long, broad distal tooth, slim subequal proximal tooth ( Fig. 10b View Figure 10 ); cheliped merus medial inferior margin with large jagged distal tooth followed by six distinct smaller teeth decreasing in size proximally ( Fig. 9b View Figure 9 ). G1TA short (TA/SS 0.3), directed outwards at 45° angle to longitudinal axis of G1SS, with distinct longitudinal groove, proximally distinctly broad, abruptly narrow, slim and tube-like at distal two-thirds ( Figs 11b View Figure 11 , 12b View Figure 12 ). G1SS tapering slightly from wide basal margin to relatively wide distal margin (0.6 × SS basal margin); dorsal face with broad dorsal membrane (maximum width 0.1 × SS length) at TA/SS junction ( Fig. 11b View Figure 11 ). G2TA long (TA/SS = 0.40), flagellum-like, almost as long as G2SS. Mature between CW 13-17 mm.

Redescription.

A re-description of L. balssi is given in Mvogo Ndongo et al. (2018). Additional character state descriptions are added here in the light of the new material to further distinguish between L. balssi and its congeners.

Remarks.

Specimens of L. balssi are known only from Kumba and Mt. Manengouba in southwestern Cameroon. The morphological features of L. balssi are mainly defined from the adult male specimens collected from Mt. Manengouba ( Mvogo Ndongo et al. 2018). The only available specimens from Kumba are sub-adults whose gonopod, sternal, and cheliped characters are not fully developed, which makes them less useful for taxonomic studies ( Cumberlidge 1999). Further systematic surveys at the type locality near Kumba are needed to resolve this taxonomic problem but current social issues in this part of Cameroon preclude such surveys. Distinctions between L. balssi and its congeners are given below under general remarks.