Raddaus mertensi ( Bott, 1956 )

Magalhães, Célio & Wehrtmann, Ingo S., 2025, Taxonomic revision and distribution of the freshwater crabs of the family Pseudothelphusidae (Decapoda, Brachyura) from Guatemala, with the descriptions of two new species and keys to the species of all genera, Zoosystema 47 (26), pp. 581-615 : 600

Raddaus mertensi ( Bott, 1956)

( Figs 6D, E; 16)

Pseudothelphusa cobanensis mertensi Bott, 1956: 231 , pl. 30, fig. 3ac, pl. 35, fig. 3a, b.

Raddaus mertensi – Cumberlidge et al. 2014: 147 (in table). — Wehrtmann et al. 2016: 781 (in list). — Acevedo-Alonso & Cumberlidge 2022: 583 (Appendix 2, in list).

TYPE MATERIAL EXAMINED. — Holotype. El Salvador • 1♂ (37.3:24.4); Santa Ana, Los Planes Farm [northeast of Metapán, Montecristo National Park; 14°24’N, 89°22’W]; 1830 m elev.; 30.X.1950; R. Mertens leg.; SMF 1822 .

OTHER MATERIAL EXAMINED. — Guatemala • 1 ♂ (soft carapace) 3 juv. ♀; Chiquimula, Río Atulapa, 3 miles east of Esquipulas, on road CA 10 ; [ 14°33’45”N, 89°18’37”W; 916 m elev.]; 5.IV.1971; R. M. Bailey leg.; USNM 1089229 .

DISTRIBUTION. — Guatemala ( Chiquimula) ( Fig. 16), Honduras ( Ocotepeque) and El Salvador ( Santa Ana) ( Bott 1956; Wehrtmann et al. 2016; Acevedo-Alonso & Cumberlidge 2022; Magalhães & Wehrtmann 2025; this study).

DESCRIPTION OF G1 ( Fig. 6D, E)

Stout, straight in mesial view, narrow in proximal 2/3, very wide in distal third, moderately compressed mesolaterally; caudal and cephalic margins straight in mesial view. Marginal suture on mesial surface straight up to apex along most of stem, slightly curved in caudal direction in distal quarter, with short row of large marginal setae along proximal portion. Marginal process somewhat narrow, rounded, not extending beyond mesial margin of apex. Lateral suture incomplete, marked by shallow sulcus on caudal surface. Mesial process greatly widened, slightly wider (roughly 1.2 times) than main stem, subretangular, directed cephalad, bilobed, with proximal lobe bearing broadly subtriangular teeth pointing basally; distal lobe as narrow subtriangular teeth slightly shorter than proximal lobe in mesial view; mesial lobe with proximal margin bearing short row of minute setae; distal margin slightly crenulate, cephalic surface slightly concave in lateral view, bearing strong triangular, subdistal spine pointing cephalad, and small, rounded protuberance located just below subdistal spine.Apex oblong, short, situated obliquely, open, mesial slightly higher than lateral one; field of apical spines moderately developed, with short small spines; spermatic channel opening on apex cavity, situated towards caudal end.

REMARKS

This species was known only from its type locality, in the department of Santa Ana, in northwestern El Salvador. Later, Acevedo-Alonso & Cumberlidge (2022) listed the occurrence of this species in Guatemala and Honduras without specifying voucher material or distributional data. Thus, our report herein represents the first published record of this species for Guatemala.