Alvarezius zongolicae ( Alvarez, Villalobos & Moreno, 2012 ) Moreno-Juárez & Villalobos & Álvarez, 2022

Moreno-Juárez, Eric G., Villalobos, José Luis & Álvarez, Fernando, 2022, Two new genera and one new species of freshwater crabs of the subfamily Pseudothelphusinae (Decapoda: Brachyura: Pseudothelphusidae) from southwestern Mexico, Zootaxa 5200 (1), pp. 24-36 : 32-33

Alvarezius zongolicae ( Alvarez, Villalobos & Moreno, 2012) n. comb.

Pseudothelphusa zongolicae Alvarez, Villalobos & Moreno, 2012 , figs. 2, 3. — Villalobos et al., 2019: 157 ( Table 1 ). — Álvarez et al., 2020: 10 (Supplementary material, Table 1 ).

Type material. Holotype: CNCR 26641 ; 1 ♂, CL 18.1 mm, CW 30.0 mm; spring at Choapa (18°43’32”N, 96°57’07”W, 1053 m asl), Municipality of Zongolica , Veracruz, Mexico; colls. E. Moreno, O. Trejo; 19 April 2011 . Paratype: CNCR 26642 ; 1 ♂, CL 17.7 mm, CW 28.7 mm; same locality as holotype; 12 June 2011 .

Other material examined. CNCR26643 , 4♂, 1♀,CL 15.8–22.8mm,CW 25.5–37.5 mm, Macuilca (18°38’49”N, 96°56’58”W, 528 m asl), Municipality of Zongolica, Veracruz, Mexico, coll. E. Moreno & O. Trejo, 11 June 2011 ; CNCR 29494 , 5 ♂, CL 8.9–19.9 mm CW 13.6–32.7 mm, spring of water, Tepeplampa (18°33’41”N, 96°56’51”W, 891 m asl), Municipality of Zongolica, Veracruz, Mexico, coll. E. Moreno & S. Rodríguez, 12 December 2012 ; CNCR 29495 , 6 ♂, 1 ♀, CL 11.2–23.3 mm, CW 12.5–40.6 mm, stream near Tepetlampa (18°33’10”N, 96°56’30”W, 110 m asl), Municipality of Zongolica, Veracruz, Mexico; colls. E. Moreno & S. Rodríguez; 11 December 2012 ; CNCR 35458 , 2 ♂, 2 ♀, CL 18.1–21 mm, CW 22.4–36.2 mm, same locality as holotype, coll. E. Moreno, A. Soto & R. Rodríguez , 10 October 2019 ; CNCR 36478 , 4 ♂, 4 ♀, CL 7.8–9.8 mm, CW 10.6–15.6 mm, spring inside cave, Cintalapa (18°38’12”N, 96°54’0.4”W, 1050 m asl), Municipality of Zongolica, Veracruz, Mexico; colls. E. Moreno & L. Gómez; 3 April 2022 . CNCR 36479 ; 2 ♂, spring in Acahualco , Cuahutilica (18°36’19.6”N, 96°56’26”W, 1169 m asl), Municipality of Zongolica, Veracruz, Mexico; colls. E. Moreno & L. Gómez, 3 April 2022 ; CNCR 36480 , 1 ♂, CL 23.2 mm, CW 39.9 mm, waterfall on the road, Coapa-Pinopa (18°37’16.2”N, 96°56’21.5”W, 1063 m asl), Municipality of Zongolica, Veracruz, Mexico, coll. E. Moreno & L. Gómez, 3 April 2022 ; CNCR 36481 , 3 ♂, CL 20.7–24.2 mm, CW 34.9–41.4 mm, Acahualco Cave , Cuahutilica (18°36’16”N, 96°56’09”W, 1,111 m asl), Municipality of Zongolica, Veracruz, Mexico, coll. E. Moreno & L. Gómez, 3 April 2022 .

Description. Carapace transversely oval, dorsal surface slightly convex, smooth, finely punctate, regions faintly marked, except for moderately swollen mesobranchial region ( Fig. 5a ). Superior frontal border present, incomplete towards middle portion, formed by incomplete row of granules, in frontal view inclined towards median groove ( Fig. 5b ). Inferior frontal border complete, thick, slightly rounded in dorsal view, bilobed in frontal view, extending laterally to form superior margin of orbits. Median groove deep, narrow, arising above inferior frontal border, extending posteriorly beyond postfrontal lobes. Postfrontal lobes low, well defined. Cervical grooves wide, shallow, straight towards margin of carapace, ill- defined, slightly arching towards central portion of carapace, not reaching anterolateral margin. Walking legs typical of genus. Chelipeds asymmetrical. Major chela right, palm somewhat swollen, movable finger half-length of chela, fingers not gaping; both fingers with irregular arrangement of teeth of varying sizes, both fingers curved inwards ( Fig. 5c ). Third maxilliped with merus showing complete rounded external margin, ischium rectangular, ratio ischium/exopod 0.85 ( Fig. 5d ).

G1 moderately slender, distal half of principal axis showing mesial torsion of caudo-marginal projection. In mesial view ( Fig. 5e ), marginal suture evident, arching distally, disappearing under caudo-marginal projection; lobe of caudo-marginal projection (Cmp) axe-shaped, large, about half length of gonopod, cephalic border smooth; caudo-marginal distal crest straight, spinulated at cephalic curvature. In cephalic view ( Fig. 5f ), mesial process (Mp) oriented laterally, slightly inclined proximally, tapering laterally, ending in two acute tips, superior margin closing apex cavity, extending towards internal portion of apex cavity forming central crest; caudo-marginal projection with single large, axe-shaped lobe, extending proximally slightly beyond half-length of gonopod, cephalic margin armed with small, acute teeth; crest of caudo-marginal projection becoming less thick cephalically; conical prominence (Cp) on caudal angle of lateral crest bearing apical setae. In lateral view ( Fig. 5g ), mesial process with two tips oriented laterally; caudo-marginal projection (Cmp) appearing as large tongue-shaped lobe; conical prominence (Cp) emerging from lateral crest. In caudal view ( Fig. 5h ), caudal surface showing torsion of gonopod; mesial process (Mp) subtriangular; conical prominence (Cp) of lateral crest evident; lobe of caudo-marginal projection (Cmp) elongate, slender, extending parallel to main axis of gonopod; marginal suture straight, visible along proximal two thirds of gonopod. In apical view ( Fig. 5i ), apex cavity approximately rectangular, field of spines (Sf) on lateral side of cavity, extending to conical prominence (Cp); central crest of apex cavity sharp, slightly undulated; distal crest of lateral surface straight; mesial process (Mp) subtriangular, distal margin rounded; lobe of caudo-marginal projection (Cmp) as undulated sheet, cephalic margin with minute spines; opening of sperm channel caudal.

Distribution. Mexico, Veracruz, in the surroundings of the Municipality of Zongolica.

Type locality. Spring at Choapa (18°43’32”N, 96°57’07”W; 1,053 m asl), Municipality of Zongolica , Veracruz, Mexico ( CNCR 26641 ) .

Remarks. The term “conical projection” of the latero-caudal portion of the distal border of the apical cavity from the original description by Álvarez et al. (2012) is now changed to “conical lobe”, since the former suggests the fusion of two plates in a single apical process ( Hobbs 1942, 1945; Smalley 1964); however, in this case the structure develops directly from the lateral surface.

Figures

FIGURE 5. Alvarezius zongolicae n. comb. a) carapace dorsal view, b) carapace frontal view, c) chela, d) third maxilliped. G1 views: e) mesial, f) cephalic, g) lateral; h) caudal, i) distal. Abbreviations: Cmp) caudo-marginal projection; Csp) Conical setiferous prominence; Mp) Mesial process; Sf) spine field. Scales as broad lines e-h: 2 mm; i: 1 mm (taken and modified from Alvarez et al. 2012).