Caecidotea mintzita García-Vázquez & Pedraza-Lara & Rodríguez-Almaraz 2021, sp. nov.

Caecidotea mintzita sp. nov.

(Figs 14–17)

Material examined: Holotype, male (CNCR 35510), length 7.6 mm, Channel that flows next to the Mintzita spring, 19°38’53.74”N, 101°16’15.53”W, elev. 1892 m, Municipality La Mintzita, Michoacan, Mexico, 20 March 2018, coll. L. García-Vázquez and C. Pedraza-Lara.

Paratypes, male (CNCR 35511), length 7.0 mm; same data of collection and collectors as holotype; dissected parts pereiopod I, pereiopod IV, pleopod II; dissected structures for right pleopod drawings I, III, IV and V in the specimen tube. Females present in the same container.

Diagnosis. Male body length 3.7 times width; postmandibular lobes not produced; antennula flagellum exceeds last antennal segment, with pectinate setae in each article; antenna flagellum reaches anterior edge pereionite 6; antenna flagellum with 73 articles. Uropods 1.2 times pleotelson length.

Description. Male (CNCR 35511) 7.6 mm (Fig. 14A); head width 1.6 length, anterior margin concave. Eyes present, oval, dark pigmented, length 0.5 times longer than wide. Postmandibular lobes not produced. Subrectangular pereionites ornamented with lateral setae.

Pereionite 1 length 1.0 pereionite 2 length; pereionite 1 1.1 pereionite 3 length; pereionites 6–7 with subrectangular margins, widening posterior.

Antennula flagellum with 11 articles, reaching distal edge antenna podomere; last four segments with aestetascs in formula 1–1–1–1. Antenna flagellum with 73 articles with pectinate setae in each article; proximal article longer than wide; last 15 elongated.

Pereiopod I (Figs 14B, 15A–B) dactylus as long as palm, with simple setae; inner and outer palmar margin with row simple setae; proximal process with 3 robust setae; mesial process acute exceeding dactylus, distal process subacute; 0.5 mesial process length. Pereiopods II–III (Fig. 14C–D) similar length. Pereiopod IV (Figs 14E, 15C) propodus with spine in dactylus, robust 0.6 times dactylus width, dactylus length 0.6 propodus length, dactylus with row 3 strong spines. Pereiopod V (Fig. 14F) basis length 1.2 propodus length. Pereiopod VI (Fig. 14G) similar length to pereiopod VII, basis length 1.2 propodus length. Pereiopod VII (Fig. 14H) 0.6 body length.

Pleopod I (Fig. 16A) length 1.1 pleopod II length; protopod subrectangular, proximal margin rounded, length 1.5 width, inner margin with 4 retinacula, subrectangular distal segment, outer margin curved, length 2.0 width, margins with 21 simple setae.

Pleopod II (Fig. 17A–F), protopod subrectangular, proximal edge rounded, distal border with cuticular scales; exopod base with 2 spines in right upper corner; exopod oval with cuticular scales, distal margin with 20–22 plumose setae; slender endopod, mesial curved, length 3.9 width, exopod length 0.7 protopod length, internal and external process prominent, endopod apex with 3 processes: cannula conical, similar to a rolled blade; mesial process evident; caudal process robust, subconical, with rounded apex, armed on subapical dorsal surface with 4–18 cuticular scales.

Pleopod III (Fig. 16B), exopod oval with distal margin setose, length 1.1 endopod length, width 1.6 endopod width, transverse suture in proximal half, distal margin with 12 plumose setae, external margin with 34 simple setae; endopod short oval, 0.8 exopod length.

Pleopod IV (Fig. 16C), length 1.6 width, outer margin exopod with 6 proximal setae, endopod length 0.9 exopod length.

Pleopod V (Fig. 17D), exopod oval, as long as 1.9 width; transverse suture not evident; outer margin with 5 proximal setae, endopod as long 0.9 as wide exopod.

Pleotelson (Fig. 17E), subsquare, width1.0 length, lateral margins curved, with several simple setae, caudomedial lobe subacute produced.

Uropods (Fig. 17E), 1.2 pleotelson length, armed with robust marginal setae; endopod length 1.3 exopod length; exopod as long as protopod.

Habitat. The specimens of Caecidotea mintzita sp. nov. were collected in a channel that flows next to La Mintzita spring, 60 cm wide and 40 cm deep, just below of submerged rocks and at the roots of the riparian vegetation.

Distribution. Only known from the type locality.

Etymology. This species is named after the Mintzita spring.

Remarks. Caecidotea mintzita sp. nov. is similar morphologically to the species C. xochimilca Rocha-Ramírez & Peñaloza-Daniel, 2011. The former species can be differentiated by the endopod apex cuticular scales conformation, which is 4–18 while in C. xochimilca 3–10 cuticular scales. The endopod length is 1.1 protopod length in C. xochimilca while in Caecidotea mintzita sp. nov. the endopod length 1.3 exopod length.