Louisea edeaensis (Bott, 1969)

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/753C9217-7DAB-5B4E-83A2-B578150518A8
treatment provided by	ZooKeys by Pensoft
scientific name	Louisea edeaensis (Bott, 1969)
status

Treatment

Louisea edeaensis (Bott, 1969) Figs 2a View Figure 2 , 3a View Figure 3 , 4c View Figure 4 , 5a View Figure 5 , 6a View Figure 6 , 7a View Figure 7 , 8a, b View Figure 8 , 9a View Figure 9 , 10a View Figure 10 , 11a View Figure 11 , 12a View Figure 12 , 13a View Figure 13 , 14a View Figure 14 , 15a View Figure 15

Globonautes macropus edeaensis Bott 1969: 360; 1970: 24, pl. 1, figs 3-5, pl. 26, fig. 8; Cumberlidge 1987: 2215, table 2.

Louisea edeaensis Cumberlidge 1994: 124, fig. 1, table 1; 1997: 577; 1999: 227, 5300, 54-57, figs 46F, 47E, 48E, 49F, 51F, 52F, 53DD, 54-57, 62F, 68F, table IX, plate 3; Ng et al. 2008: 169 (list); Cumberlidge et al. 2009: 6; Mvogo Ndongo et al. 2017a: 273, figs 1-3; 2017c: 440, fig. 1.

Material examined.

CAMEROON. Holotype: adult male (CW 22.5 mm), Edea, Jan 1910, coll. Riggenbach (ZSBS 1118/1). Adult male, 2 adult females (CWs 19.4, 17.5 mm), Yaounde, 1907, coll. Haberer (NHMW 1877). See Table 2 View Table for details of the material examined from Lake Ossa.

Diagnosis.

Amended from Cumberlidge (1994, 1999); Mvogo Ndongo et al. (2017a). Carapace smooth, urogastric groove faint ( Figs 2a View Figure 2 , 3a View Figure 3 , 4c View Figure 4 ). Postfrontal crest faint, complete, meeting anterolateral margin behind intermediate tooth ( Fig. 7a View Figure 7 ). Exorbital, intermediate teeth small, low, distinct ( Figs 2a View Figure 2 , 3a View Figure 3 , 4c View Figure 4 , 7a View Figure 7 ). Third maxilliped ischium with distinct vertical groove ( Fig. 14a View Figure 14 ). Terminal segment (TS) of mandibular palp bilobed, with large distinct anterior lobe (0.6 × terminal segment length) ( Fig. 15a View Figure 15 ). Major cheliped dactylus relatively stout, straight, with two large teeth (one proximal, one medial) ( Fig. 8a View Figure 8 ); cheliped propodus with four large teeth (three proximal, one distal); cheliped carpus inner margin with long, broad distal tooth followed by slim, smaller proximal tooth ( Fig. 10a View Figure 10 ). G1TA short (TA/SS = 0.3), directed outward at 45° angle to longitudinal axis of G1SS, proximally broad, distal two-thirds narrowing abruptly to form slim tube ( Figs 11a View Figure 11 , 12a View Figure 12 ). G1SS tapering slightly from broad 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. 11a View Figure 11 ). G2TA long (TA/SS = 0.40), flagellum-like, almost as long as G2SS ( Fig. 13a View Figure 13 ). Mature between CWs 14-23 mm.

Re-description.

Amended from Cumberlidge (1994, 1999). Carapace ovoid, high, slightly arched (CH/FW 1.41, N = 22), wide (CW/FW 3.14, N = 22), smooth; postfrontal crest poorly defined, completely crossing carapace, meeting anterolateral margins of carapace behind intermediate tooth ( Fig. 7a View Figure 7 ); mid-groove broad, shallow, epigastric crests poorly defined ( Fig. 7a View Figure 7 ); external orbital tooth small, low; epibranchial tooth reduced to granule, almost undetectable ( Figs 4a View Figure 4 , 7a View Figure 7 ); intermediate tooth on anterolateral margin between external orbital, epibranchial teeth small but detectable ( Figs 4a View Figure 4 , 7a View Figure 7 ); anterolateral margin lined by small granules ( Figs 4a View Figure 4 , 7a View Figure 7 ); posterolateral margin continuous with anterolateral margin, curving inward; posterior margin of carapace wide (2/3 CW). Carapace branchiostegal wall with 2 sutures dividing it into 3 parts ( Fig. 6a View Figure 6 ); longitudinal suture beginning at respiratory opening dividing suborbital, subhepatic regions from pterygostomial region ( Fig. 6a View Figure 6 ); vertical suture beginning at epibranchial tooth curving sharply down to meet longitudinal suture, marked by row of granules ( Figs 6a View Figure 6 , 7a View Figure 7 ). Sternal sulcus s2/s3, deep, complete, s3 lacking depression ( Fig. 5a View Figure 5 ); s3/s4 reduced to 2 short, distinct notches on each side of sternum ( Fig. 5a View Figure 5 ); episternal sulci s4/e4, s5/e5, s6/e6 faint or missing, s7/e7 complete ( Fig. 5a View Figure 5 ). Mandibular palp 2 segmented; terminal segment (TS) bilobed, anterior lobe 0.6 × length of terminal segment ( Fig. 15a, d View Figure 15 ). Third maxillipeds ( Fig. 6a View Figure 6 ) filling entire buccal cavern, except for transversely oval efferent respiratory openings in superior lateral corners; ischium with distinct vertical groove ( Fig. 14a View Figure 14 ); exopod lacking flagellum ( Fig. 14a View Figure 14 ).

Male chelipeds greatly unequal, right cheliped larger than left cheliped ( Figs 3a View Figure 3 , 6a View Figure 6 ). Dactylus, propodus of right (major) cheliped slim, elongated; fixed finger (propodus) with 4 large pointed teeth (3 proximal, 1 distal); movable finger (dactylus) relatively stout, straight, with 2 large teeth (1 proximal, 1 medial) ( Fig. 8a View Figure 8 ). Dactylus, propodus of left (minor) cheliped slender, with small teeth on occluding margins ( Figs 2a View Figure 2 , 3a View Figure 3 ). Medial inferior margin of cheliped merus with large jagged distal tooth angled outward at 90°, followed by numerous distinct smaller teeth decreasing in size proximally ( Figs 6a View Figure 6 , 9a View Figure 9 ; see Mvogo Ndongo et al. 2017a: fig. 1B). Cheliped carpus inner margin with 2 large pointed teeth, distal tooth long, broad with pointed tip; proximal tooth longer than distal tooth ( Fig. 10a View Figure 10 ). Walking legs (p2-p5) slender, p4 longest, p5 shortest; dactyli (p2-p5) tapering to point, each bearing rows of downward-pointing sharp bristles, p5 dactylus shortest ( Figs 2a View Figure 2 , 3a View Figure 3 ).

Male pleon triangular, telson (a7) rounded at distal margin ( Fig. 5a View Figure 5 ). G1TA short (TA/SS 0.3), directed outward at 45° angle to longitudinal axis of G1SS, proximally distinctly broad, abruptly narrow, slim and tube-like at distal two-thirds ( Figs 11a View Figure 11 , 12a View Figure 12 ). G1SS tapering slightly from broad 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. 11a View Figure 11 ); ventral face with raised triangular flap extending halfway across segment forming roof of chamber for G2, flap tapering diagonally from broad base to narrow point at SS/TA junction ( Fig. 12a View Figure 12 ). G2TA long (TA/SS = 0.40), flagellum-like, almost as long as G2SS ( Fig. 13a View Figure 13 ); G2SS wide at base, tapering sharply to long, thin process with raised rim at junction with TA ( Fig. 13a View Figure 13 ). Mature between CW 14-23 mm.

Remarks.

The description and diagnosis of L. edeaensis by Cumberlidge (1994) was based on characters of specimens from Edea and Yabassi. Mvogo Ndongo et al. (2017a) updated these characters following the discovery of a large series of L. edeaensis from Bedimet Island in Lake Ossa in August 2015. These specimens included only one adult male that agreed well with the diagnostic characters of the holotype from Edea, and with other specimens from Yaounde and Yabassi. Nevertheless, the morphological variations raised by Cumberlidge (1994) that distinguished the specimens from Yabassi from those from Yaounde, Edea, and Lake Ossa still remained. The specimens of Lake Ossa examined in this study included five adult males whose morphological characters are consistent with those from Edea and Yaounde, but different from the specimens from Yabassi. This resulted in the present re-description of L. edeaensis . Differences between L. edeaensis and its congeners are given below under general remarks.