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Caecidotea chicoensis sp. nov. (Figs 10–13) Material examined: Holotype, male (CNCR 35516), length 9.5 mm, National Park Mineral del Chico, spring behind the visitor center, 20°11’01”N, 98°42’57”W, elev. 2985 m, Municipality Mineral del Chico, Hidalgo, Mexico, 12 December 2018, coll. L. García-Vázquez and M. C. Jordán-Hernández. Paratypes, male (CNCR 35517) length 9.5 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 3 times its width. Head rectangular, width 2.7 length, anterior margin concave; eyes small, oblique oval, length 1.5 width, postmandibular lobes produced. Pleotelson lateral margins parallel, caudomedial lobe subacute produced. Pleopod II protopod ventral surface with cuticular scales on dorsal edge; exopod with ornamentation on ventral surface; endopod medial surface with elongated transverse striations. Uropods irregular, lanceolate. Description. Male (CNCR 35516) 9.5 mm (Fig. 10A); head rectangular, width 2.7 times length, anterior margin concave. Eyes present, oval, dark pigmented, length 0.4 width. Postmandibular lobes produced. Subrectangular pereionites lateral margins straight with setae, as well as on dorsal surface. Pereionite 1 length 1.0 pereionite 2 length; pereionite 1 0.9 pereionite 3 length; pereionites 6–7 with subrectangular margins, posterior narrowing. Antennula flagellum with 11 articles, reaching distal antenna podomere middle, when projecting forward; last four segments with aestetascs in formula 0–1–1–1. Antenna flagellum with 67 articles; proximal article longer than wide, following articles decreasing in length. Pereiopod I (Figs 10B, 11A–B) propodus slender triangular, dactylus outer edge with simple setae as long as palm, irregular inner edge; inner and outer palmar margin with row simple setae; proximal process with 3 robust setae; mesial process acute, exceeding dactylus width. Pereiopods II–III (Fig. 10C – D) similar length. Pereiopod IV (Figs 10E, 11C), propodus with spine in dactylus; dactylus robust; dactylus length 0.5 propodus length, lower margin with five strong spines. Pereiopod V (Fig. 10F), basis similar length to propodus. Pereiopod VI (Fig. 10G) as long as pereiopod VII, basis length similar to carpus length. Pereiopod VII (Fig. 10H) 1.2 body length. Pleopod I (Fig. 12A) as long as pleopod II; protopod subrectangular, proximal margin rounded, length 1.6 width, inner margin with 3 retinacula, distal segment subrectangular, outer margin concave, length 2.6 times width, margins with 10 simple setae. Pleopod II (Fig. 13A–F), protopod subrectangular, distal edge with cuticular scales; exopod base triangular with distal spines; exopod oval, with small cuticular scales, distal margin with 20–25 long plumose setae; slender endopod, as length 4.6 width, 1.1 exopod length 0.8 times protopod length, mesial surface curved, with irregular reticulations, internal and external process prominent; endopod apex with 3 processes: cannula subcylindrical, apex truncated with transverse striations on mesial surface, caudal process present; mesial process subtriangular, striated surface; caudal process robust, subconical, rounded apex, armed with 2–6 cuticular scales directed proximally. Pleopod III (Fig. 12B), exopod oval with distal margin setose, length 1.4 endopod length, width 1.6 endopod width, transverse suture in proximal half, 20 plumose setae on distal margin, external margin with 40 simple setae; endopod short oval, 0.7 exopod length. Pleopod IV (Fig. 12C), exopod length 1.6 width, external margin with 10 proximal setae; endopod length 0.9 exopod length. Pleopod V (Fig. 12D), exopod oval, length 1.9 width, transverse suture not evident; endopod length 0.9, width 0.9 exopod length. Pleotelson (Fig. 12E), as wide as long, lateral margins parallel, rounded with several simple setae, caudomedial lobe produced subacute. Uropods (Fig. 12E), subsquare, length 0.9 pleotelson width, armed with robust setae; endopod irregular, lanceolate, length 1.1 pleotelson length, exopod as long as protopod. Habitat. The specimens of Caecidotea chicoensis sp. nov. were located in a small spring, approximately 1 meter in diameter, located behind the visitor center of Mineral del Chico National Park. The water that emerges from the spring runs through a small channel approximately 50 cm wide; algae growths and anuran larvae were also found. Distribution. Only known from the type locality. Etymology. This species is named after the Mineral del Chico National Park. Remarks. Caecidotea chicoensis sp. nov. can be distinguished from other Mexican species of Caecidotea by the presence of elongated striations on the medial surface of pleopod II endopod., Published as part of García-Vázquez, Leonardo, Pedraza-Lara, Carlos & Rodríguez-Almaraz, Gabino, 2021, Six new epigean species of Caecidotea (Isopoda: Asellidae) distributed along the Trans-Mexican Volcanic Belt in Central Mexico, pp. 45-77 in Zootaxa 4965 (1) on pages 56-61, DOI: 10.11646/zootaxa.4965.1.2, http://zenodo.org/record/4723078

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., Published as part of García-Vázquez, Leonardo, Pedraza-Lara, Carlos & Rodríguez-Almaraz, Gabino, 2021, Six new epigean species of Caecidotea (Isopoda: Asellidae) distributed along the Trans-Mexican Volcanic Belt in Central Mexico, pp. 45-77 in Zootaxa 4965 (1) on pages 61-64, DOI: 10.11646/zootaxa.4965.1.2, http://zenodo.org/record/4723078

Caecidotea alvarezi sp. nov. (Figs 2–5) Material examined: Holotype, male (CNCR 35519), length 5.0 mm, shore of the Chapala Lagoon, Jamay, 20°17’07.00”N, 102°42’36.97”W, elev. 1524 m, Municipality of Jamay, Jalisco, Mexico, 19 March 2018, coll. L. García-Vázquez and C. Pedraza-Lara. Paratypes, male (CNCR 35520), length 4.7 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 2.8 times longer than wide. Head trapezoidal, width 0.6 length, anterior margin straight; eyes 3 times longer than wide, postmandibular lobes not produced. Pleotelson lateral margins parallel, caudomedial lobe produced, broad, rounded. Pleopod II exopod with cuticular scales directed distally, as long as those in medial margin cannula; endopod with flagella, mesial process almost high as cannula. Uropods long as pleotelson length. Description. Male (CNCR 35519) 5.0 mm (Fig. 2); head width 2.8 length, anterior margin straight. Eyes present, oval, dark pigmented, length 0.6 width. Postmandibular lobes not produced. Subrectangular pereionites lateral margins ornamented with setae, pereionites 1–2 rounded, pereionites 3–5 straight, pereonites 6–7 rounded, posterior angle produced. Pereionite 1 length 1.1 pereionite 2 length; pereonite 1 0.9 pereionite 3 length; pereionites 6–7 wider, widening in posterior angle. Antennula flagellum with 10 articles, longer than distal antenna podomere middle; last four segments with aestethascs in formula 1–1–1–0. Antenna flagellum with 50 articles; proximal article wider than long; following articles decreasing in length. Pereiopod I (Figs 2B, 3A–B) propodus slender, dactylus longer than palm with five simple setae on outer surface, irregular inner edge; palmar margin with row simple setae; proximal process with robust spine length 0.3 mesial process length; mesial process acute, exceeding dactylus width. Pereiopods II–III (Fig. 2C–D) similar length. Pereiopod IV (Figs 2E, 3C–D), propodus with spine in dactylus; dactylus length 0.5 propodus length with 3 spines on lower margin. Pereiopod V (Fig. 2F) basis 1.3 propodus length. Pereiopod VI (Fig. 2G) similar length to pereiopod VII length, basis length 1.4 propodus length. Pereiopod VII (Fig. 2H) 0.5 body length. Pleopod I (Fig. 4A) length 1.1 pleopod II length; protopod trapezoidal, proximal margin straight, length 1.5 width, inner margin with 5 retinacula, distal segment subrectangular, outer margin concave, length 2.3 width, margins with 20 simple setae. Pleopod II (Fig. 5A–F), protopod subrectangular, proximal edge rounded; exopod oval, in dorsal view with two vertical rows cuticular scales adjacent to inner margin, distal margin with 20 short plumose setae; slender endopod, as long as 3.8 width, similar to exopod 0.7 protopod length, curved mesial surface with flagella, internal and external process prominent, with suture close to base; endopod apex with 3 processes: cannula short, shaped as ribbed blade, not closed, tip truncated rounded, almost reaching apex caudal process, ventral groove present, extending proximally from base to cannula more than 3.0 its length; mesial process evident, with transverse grooves on surface; caudal process robust, conical, rounded apex, armed on subapical dorsal surface with 7–17 cuticular scales directed proximally. Pleopod III (Fig. 4B), exopod oval with distal margin setose, length 1.1 endopod length, width 1.6 endopod width, transverse suture in proximal half, 15 plumose setae on distal margin, external margin with 6 simple setae; endopod short oval, 0.9 exopod length. Pleopod IV (Fig. 4C), exopod as long as 1.7 width, with pronounced notch, on outer margin, close to pleopod joint; endopod 0.9 exopod length. Pleopod V (Fig. 4D), exopod oval, as long as 1.8 width; transverse suture not obvious; endopod length 0.9 exopod length, width 0.7 exopod width. Pleotelson (Fig. 4E), subsquare, width 1.1 length, lateral margins parallel, with simple setae, caudomedial lobe broad rounded. Uropods (Fig. 4F), length equal to pleotelson length, armed with robust setae; length 0.5 endopod length; endopod linear, length 0.8 protopod length, exopod length 1.1 protopod length. Habitat. This species was collected on the shoreline of the Chapala lagoon within the roots of the water lily Eichornia crassipes, along with other crustaceans (e.g., crayfish of the genus Cambarellus and amphipods of the genus Hyalella). Distribution. Only known from the type locality. Etymology. This species is named in honor to Dr. Fernando Alvarez, curator of the National Crustacean Collection, in recognition to his career in the study of Mexican crustaceans. Remarks. C. alvarezi sp. nov. is similar to the species C. williamsi Escobar-Briones & Alcocer, 2002 from Laguna de Alchichica, Puebla. The two species, however, can be distinguished by the number of retinacula in pleopod I (3 in C. williamsi and 5 in C. alvarezi sp. nov.) and the shape of pereiopod I. C. williamsi has only mesial process, while C. alvarezi sp. nov. has both mesial and proximal processes., Published as part of García-Vázquez, Leonardo, Pedraza-Lara, Carlos & Rodríguez-Almaraz, Gabino, 2021, Six new epigean species of Caecidotea (Isopoda: Asellidae) distributed along the Trans-Mexican Volcanic Belt in Central Mexico, pp. 45-77 in Zootaxa 4965 (1) on pages 48-50, DOI: 10.11646/zootaxa.4965.1.2, http://zenodo.org/record/4723078

Caecidotea zacapuensis sp. nov. (Figs 22–25) Material examined: Holotype, male (CNCR 35522), length 7.5 mm, Laguna de Zacapu, 19°49’37.00”N, 101°47’23.00”W, elev. 1993 m, Municipality Zacapu, Michoacan, Mexico, 20 March 2018, coll. L. García-Vázquez and C. Pedraza-Lara. Paratypes, male (CNCR 35523), length 7.6 mm; same data of collection and collectors as holotype; dissected parts left pereiopod I, left pereiopod IV, pleopod II; dissected structures for right pleopod drawings I, III, IV and V in the specimen tube. 20 Males and 15 females (CNCR 35524). Diagnosis. Male body length 3.4 width. Head trapezoidal, width 2.4 length, anterior margin concave; eyes length 3.8 width. Pleopod III with 36 plumose marginal setae. Exopod pleopod IV with proximal incomplete transverse suture. Uropods length 0.7 pleotelson length. Description. Male (CNCR 35522) 7.5 mm (Fig. 22A); head trapezoidal, width 2.4 length, anterior margin concave; eyes present, oval, dark pigmented, length 3.8 width. Postmandibular lobes not produced. Subrectangular pereionites lateral margins with simple setae, pereionites 1–5 straight, pereionites 6–7 rounded. Pereionite 1 length 1.2 pereionite 2 length; pereionite 1 1.1 pereionite 3 length; pereionites 6–7 with lateral margins rounded, widening posterior. Antennula flagellum with 10 articles, longer than distal antenna podomere middle; last four segments with aestetascs in formula 1–0–1–1. Antenna flagellum with 65 articles; proximal article width 1.2 length; following articles decreasing in length. Pereiopod I (Figs 22B, 23A – B) dactylus outer edge with 10 simple setae; dactylus longer than palm; palmar margin with row simple setae; proximal process with 3 robust spines; mesial process acute, as wide as dactylus; distal process small acute triangular. Pereiopods II–III (Fig. 22C–D) similar length. Pereiopod IV (Figs 22E, 23C) propodus with spine in dactylus, dactylus length 0.6 propodus length, dactylus with 4 slender spines on lower margin. Pereiopod V (Fig. 22F) basis length 1.2 propodus length. Pereiopod VI (Fig. 22G) similar length to pereiopod VII, basis length 1.3 propodus length. Pereiopod VII (Fig. 22H) length 0.6 body length. Pleopod I (Fig. 24A) length 2.2 pleopod III length; basal segment oval, proximal margin straight, length 1.4 width, inner margin with 6 retinacula, distal segment oval, external margin medially straight, length 1.9 width, margins with 20 simple setae. Pleopod II (Fig. 25A–F), protopod subrectangular, proximal edge rounded, internal margin with 2 simple spines; exopod oval with small cuticular scales on inner and outer margin, exopod margin with 22 plumose setae; endopod slender, curved mesial surface, length 3.2 width, length 0.9 exopod length, length 0.7 protopod length, internal and external processes prominent; endopod apex with 3 processes: cannula short subcylindrical surpassing caudal process, like a semi-rolled sheet; mesial process evident; caudal process robust, subconical, with rounded apex, armed on subapical dorsal surface with 2–17 cuticular scales. Pleopod III (Fig. 24B), exopod oval, length 1.5 width, width 1.6 endopod length, transverse suture in proximal half, 36 plumose setae in distal and proximal margins; endopod subrectangular, length 0.9 exopod length. Pleopod IV (Fig. 24C), exopod length 1.6 width, external proximal margin with incomplete transverse suture, close to pleopod joint; endopod length 0.8 exopod length. Pleopod V (Fig. 24D), exopod oval, length 1.8 width, transverse suture not evident; endopod length 0.9 exopod length, width 0.8 exopod width. Pleotelson (Fig. 24E), subsquare, length 1.0 width, lateral margins parallel, with simple marginal setae, caudomedial lobe produced subacute. Uropods (Fig. 24E), length 0.7 pleotelson length, armed with robust marginal setae, apical endopod setae, exopod length 1.2 endopod length; protopod length 1.1 exopod length. Habitat. This species was located on the shore of the Zacapu lake, between the roots of the aquatic vegetation, in the water lily Eichornia crassipes. Distribution. Known only from the type locality. Etymology. This species is named after the municipality Zacapu, where it inhabits. Remarks. The pleopod IV of Caecidotea zacapuensis sp. nov. is similar to the one of Caecidotea buzwilsoni sp. nov. from Yuriria Lagoon. Both can be differentiated using the transverse suture in pleopod IV: incomplete in Caecidotea zacapuensis sp. nov., and complete in Caecidotea buzwilsoni sp. nov., Published as part of García-Vázquez, Leonardo, Pedraza-Lara, Carlos & Rodríguez-Almaraz, Gabino, 2021, Six new epigean species of Caecidotea (Isopoda: Asellidae) distributed along the Trans-Mexican Volcanic Belt in Central Mexico, pp. 45-77 in Zootaxa 4965 (1) on pages 70-75, DOI: 10.11646/zootaxa.4965.1.2, http://zenodo.org/record/4723078

Six new epigean freshwater species of the genus Caecidotea in Mexico are described. These species were collected in waterbodies located along the Trans-Mexican Volcanic Belt (TMVB) and the eastern slope of the country: Caecidotea buzwilsoni sp. nov., Caecidotea chicoensis sp. nov., Caecidotea alvarezi sp. nov., Caecidotea mintzita sp. nov., Caecidotea zacapuensis sp. nov., and one additional species Caecidotea villalobosi sp. nov. is described from the Papaloapan basin at the Atlantic Slope of Mexico. The taxonomic treatment for each species includes a detailed description, figures of characters of diagnostic importance and comments. We also provide an updated map of Caecidotea records in Mexico. This work substantially increases the number of epigean Caecidotea known to occur in Mexico to 11 species, a new total of 99 species described to North America.

Caecidotea alvarezi sp. nov. (Figs 2–5) Material examined: Holotype, male (CNCR 35519), length 5.0 mm, shore of the Chapala Lagoon, Jamay, 20°17’07.00”N, 102°42’36.97”W, elev. 1524 m, Municipality of Jamay, Jalisco, Mexico, 19 March 2018, coll. L. García-Vázquez and C. Pedraza-Lara. Paratypes, male (CNCR 35520), length 4.7 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 2.8 times longer than wide. Head trapezoidal, width 0.6 length, anterior margin straight; eyes 3 times longer than wide, postmandibular lobes not produced. Pleotelson lateral margins parallel, caudomedial lobe produced, broad, rounded. Pleopod II exopod with cuticular scales directed distally, as long as those in medial margin cannula; endopod with flagella, mesial process almost high as cannula. Uropods long as pleotelson length. Description. Male (CNCR 35519) 5.0 mm (Fig. 2); head width 2.8 length, anterior margin straight. Eyes present, oval, dark pigmented, length 0.6 width. Postmandibular lobes not produced. Subrectangular pereionites lateral margins ornamented with setae, pereionites 1–2 rounded, pereionites 3–5 straight, pereonites 6–7 rounded, posterior angle produced. Pereionite 1 length 1.1 pereionite 2 length; pereonite 1 0.9 pereionite 3 length; pereionites 6–7 wider, widening in posterior angle. Antennula flagellum with 10 articles, longer than distal antenna podomere middle; last four segments with aestethascs in formula 1–1–1–0. Antenna flagellum with 50 articles; proximal article wider than long; following articles decreasing in length. Pereiopod I (Figs 2B, 3A–B) propodus slender, dactylus longer than palm with five simple setae on outer surface, irregular inner edge; palmar margin with row simple setae; proximal process with robust spine length 0.3 mesial process length; mesial process acute, exceeding dactylus width. Pereiopods II–III (Fig. 2C–D) similar length. Pereiopod IV (Figs 2E, 3C–D), propodus with spine in dactylus; dactylus length 0.5 propodus length with 3 spines on lower margin. Pereiopod V (Fig. 2F) basis 1.3 propodus length. Pereiopod VI (Fig. 2G) similar length to pereiopod VII length, basis length 1.4 propodus length. Pereiopod VII (Fig. 2H) 0.5 body length. Pleopod I (Fig. 4A) length 1.1 pleopod II length; protopod trapezoidal, proximal margin straight, length 1.5 width, inner margin with 5 retinacula, distal segment subrectangular, outer margin concave, length 2.3 width, margins with 20 simple setae. Pleopod II (Fig. 5A–F), protopod subrectangular, proximal edge rounded; exopod oval, in dorsal view with two vertical rows cuticular scales adjacent to inner margin, distal margin with 20 short plumose setae; slender endopod, as long as 3.8 width, similar to exopod 0.7 protopod length, curved mesial surface with flagella, internal and external process prominent, with suture close to base; endopod apex with 3 processes: cannula short, shaped as ribbed blade, not closed, tip truncated rounded, almost reaching apex caudal process, ventral groove present, extending proximally from base to cannula more than 3.0 its length; mesial process evident, with transverse grooves on surface; caudal process robust, conical, rounded apex, armed on subapical dorsal surface with 7–17 cuticular scales directed proximally. Pleopod III (Fig. 4B), exopod oval with distal margin setose, length 1.1 endopod length, width 1.6 endopod width, transverse suture in proximal half, 15 plumose setae on distal margin, external margin with 6 simple setae; endopod short oval, 0.9 exopod length. Pleopod IV (Fig. 4C), exopod as long as 1.7 width, with pronounced notch, on outer margin, close to pleopod joint; endopod 0.9 exopod length. Pleopod V (Fig. 4D), exopod oval, as long as 1.8 width; transverse suture not obvious; endopod length 0.9 exopod length, width 0.7 exopod width. Pleotelson (Fig. 4E), subsquare, width 1.1 length, lateral margins parallel, with simple setae, caudomedial lobe broad rounded. Uropods (Fig. 4F), length equal to pleotelson length, armed with robust setae; length 0.5 endopod length; endopod linear, length 0.8 protopod length, exopod length 1.1 protopod length. Habitat. This species was collected on the shoreline of the Chapala lagoon within the roots of the water lily Eichornia crassipes, along with other crustaceans (e.g., crayfish of the genus Cambarellus and amphipods of the genus Hyalella). Distribution. Only known from the type locality. Etymology. This species is named in honor to Dr. Fernando Alvarez, curator of the National Crustacean Collection, in recognition to his career in the study of Mexican crustaceans. Remarks. C. alvarezi sp. nov. is similar to the species C. williamsi Escobar-Briones & Alcocer, 2002 from Laguna de Alchichica, Puebla. The two species, however, can be distinguished by the number of retinacula in pleopod I (3 in C. williamsi and 5 in C. alvarezi sp. nov.) and the shape of pereiopod I. C. williamsi has only mesial process, while C. alvarezi sp. nov. has both mesial and proximal processes.

Caecidotea villalobosi sp. nov. (Figs 18–21) Material examined: Holotype, male (CNCR 35506), length 11 mm; Lago de Catemaco, Coyame, 18°26’12”N, 95°01’27”W, elev. 359 m, Municipality Catemaco, Veracruz, Mexico, 2 November 2017, coll. L. García-Vázquez and C. Pedraza-Lara. Paratypes, male (CNCR 35507), length 10.0 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. 2 males and 3 females (CNCR 35508, CNCR 35509), Laguna Mahahual, 18°39’36”N, 95°18’30W, Municipality San Andrés Tuxtla, Veracruz, Mexico, coll. J. L. Villalobos, E. Moreno and I. Toledano. Diagnosis. Male body 3.2 times longer than wide. Head width 1.4 length, anterior margin concave, lateral margins straight; eyes width 2.1 length, postmandibular lobes not produced; Pereiopod I with dactylus inner edge serrated; dactylus pereiopod IV serrated. Description. Male (CNCR 35506) 11 mm (Fig. 18A); head trapezoidal, head width 1.4 length, anterior margin concave. Eyes present, oval, dark pigmented, width 2.1 length. Postmandibular lobes not produced. Subrectangular pereionites, lateral margins with setae. Pereionite 1 length 0.9 pereionite 2 length; pereionite 1 1.1 pereionite 3 length; pereionites 6–7 with oval margins; posterior widening. Antennula flagellum with 9 articles, longer than distal antenna podomere middle; last four segments with aestetascs with formula 1–0–1–0. Antenna flagellum with 57 articles with pectinate setae; proximal article longer than wide; following articles decreasing in length. Pereiopod I (Figs 18B, 19A–B) dactylus with robust seta on dactylus, inner edge serrated; proximal process with 3 robust setae; acute mesial process not exceeding dactylus width, bicuspid distal process. Pereiopods II– III (Figs 18C–D) similar length. Pereiopod IV (Figs 18E, 19C–D), propodus with robust finger-like projection in dactylus, dactylus length 0.9 propodus length, dactylus serrated. Pereiopod V (Fig. 18F) length basis 1.4 propodus length, dactylus curved hooked. Pereiopod VI (Fig. 18G) smaller than pereiopod VII, basis length 1.3 propodus length, dactylus with spine on lower margin. Pereiopod VII (Fig. 18H) length 0.4 body length. Pleopod I (Fig. 20A) length 1.1 pleopod II length; basal segment oval, proximal margin straight, length 1.3 width, internal margin with 3 retinacula, distal segment oval, outer margin curved in apical portion, length 1.8 width, margins with 12 simple setae. Pleopod II (Fig. 21A–F), protopod subsquare, inner proximal edge straight, with simple short distal seta, dorsal distal edge with cuticular scales; exopod base with spine on right distal border, exopod oval, with rows cuticular scales, distal margin with 15–19 long plumose setae; slender endopod, as long as 3.5 width, exopod length 0.7 protopod length; inner surface curved; internal and external processes prominent, apex with 3 terminal processes: caudal process rounded, cannula short subcylindrical, with a circular apex; mesial process present; endopod subapical portion armed with 14–16 cuticular scales. Pleopod III (Fig. 20B), exopod oval with distal margin setose, length 1.2 endopod length, width 1.9 endopod width, transverse suture in proximal half, 21 marginal plumose setae, external margin with 8 simple setae; endopod oval, 1.2 exopod length. Pleopod IV (Fig. 20C), exopod length 1.5 width, external margin with 4 proximal setae, endopod length 1.1 exopod length. Pleopod V (Fig. 20D), exopod oval, exopod length 1.9 width; external margin with 4 simple setae; transverse suture not evident; endopod notched on outer proximal edge, endopod width 1.2 exopod width. Pleotelson (Fig. 20E), subsquare, width 1.1 length, lateral margins parallel, with simple setae, caudomedial lobe produced subacute. Uropods (Fig. 20F), length 0.7 pleotelson length, armed with robust setae; endopod and exopod lanceolate, endopod length 1.0 exopod length, exopod length 1.1 protopod length. Habitat. The Caecidotea villalobosi sp. nov. specimens were collected on the shore of Catemaco Lake, below rocks submerged in water, as well as on the roots of the water lily Eichornia crassipes. It is important to mention that this species is not abundant in the region. Distribution. Known from the type locality and Laguna Mahahual, San Andrés Tuxtla, Veracruz. Etymology. This species is named after Dr. José Luis Villalobos Hiriart for being an exemplary mentor for the first author and for being an exceptional carcinologist, as well as his contributions to the knowledge of Mexican crustaceans. Remarks. Argano (1977) reported C. communis (Say, 1818) in the Catemaco lake in similar conditions where we collected Caecidotea villalobosi sp. nov., between the roots of a water lily and under submerged rocks on the shore of the lake. Argano mentioned that C. communis has a wide distribution in Mexico and also takes up Bowman’s (1975) hypothesis about an artificial introduction to Mexico due to human action. However, morphological comparisons with the species C. communis sensu Williams (1970), allow it to be clearly distinguished by the following characters: rounded head, anterior margin concave; pleotelson in C. communis is subcircular, as long as wide; caudomedial lobe obtuse produced; pleopod I wider and subrectangular, with 24 simple setae in distal margin, while Caecidotea villalobosi sp. nov. has 12 simple setae. The number of retinacula is 5 in C. communis while Caecidotea villalobosi sp. nov. has 3 retinacula; Regarding the apical elements of the pleopod II endopod, the cannula of C. communis is thin, simple, and elongated, surpassing the distal edge of the caudal process, which lacks cuticular scales. The cannula of Caecidotea villalobosi sp. nov. is short, subcylindrical, does not reach the distal edge of the caudal process and has cuticular scales., Published as part of García-Vázquez, Leonardo, Pedraza-Lara, Carlos & Rodríguez-Almaraz, Gabino, 2021, Six new epigean species of Caecidotea (Isopoda: Asellidae) distributed along the Trans-Mexican Volcanic Belt in Central Mexico, pp. 45-77 in Zootaxa 4965 (1) on pages 67-70, DOI: 10.11646/zootaxa.4965.1.2, http://zenodo.org/record/4723078, {"references":["Argano, R. (1977) Asellota del Messico meridionale e Guatemala (Crustacea, Isopoda). Accademia Nazionale dei Lincei, 171, 101 - 124.","Say, T. (1818) An account of the Crustacea of the United States, part 7. Journal of the Academy of Natural Sciences of Philadelphia, 1, 374 - 401.","Bowman, T. E. (1975) Three new troglobitic asellids from Western North America (Crustacea: Isopoda: Asellidae). International Journal of Speleology, 7, 339 - 356. https: // doi. org / 10.5038 / 1827 - 806 X. 7.4. 3","Williams, W. D. (1970) A revision of North American epigean species of Asellus (Crustacea: Isopoda). Smithsonian Contributions to Zoology, 49, 1 - 79. https: // doi. org / 10.5479 / si. 00810282.49"]}

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.

Caecidotea zacapuensis sp. nov. (Figs 22–25) Material examined: Holotype, male (CNCR 35522), length 7.5 mm, Laguna de Zacapu, 19°49’37.00”N, 101°47’23.00”W, elev. 1993 m, Municipality Zacapu, Michoacan, Mexico, 20 March 2018, coll. L. García-Vázquez and C. Pedraza-Lara. Paratypes, male (CNCR 35523), length 7.6 mm; same data of collection and collectors as holotype; dissected parts left pereiopod I, left pereiopod IV, pleopod II; dissected structures for right pleopod drawings I, III, IV and V in the specimen tube. 20 Males and 15 females (CNCR 35524). Diagnosis. Male body length 3.4 width. Head trapezoidal, width 2.4 length, anterior margin concave; eyes length 3.8 width. Pleopod III with 36 plumose marginal setae. Exopod pleopod IV with proximal incomplete transverse suture. Uropods length 0.7 pleotelson length. Description. Male (CNCR 35522) 7.5 mm (Fig. 22A); head trapezoidal, width 2.4 length, anterior margin concave; eyes present, oval, dark pigmented, length 3.8 width. Postmandibular lobes not produced. Subrectangular pereionites lateral margins with simple setae, pereionites 1–5 straight, pereionites 6–7 rounded. Pereionite 1 length 1.2 pereionite 2 length; pereionite 1 1.1 pereionite 3 length; pereionites 6–7 with lateral margins rounded, widening posterior. Antennula flagellum with 10 articles, longer than distal antenna podomere middle; last four segments with aestetascs in formula 1–0–1–1. Antenna flagellum with 65 articles; proximal article width 1.2 length; following articles decreasing in length. Pereiopod I (Figs 22B, 23A – B) dactylus outer edge with 10 simple setae; dactylus longer than palm; palmar margin with row simple setae; proximal process with 3 robust spines; mesial process acute, as wide as dactylus; distal process small acute triangular. Pereiopods II–III (Fig. 22C–D) similar length. Pereiopod IV (Figs 22E, 23C) propodus with spine in dactylus, dactylus length 0.6 propodus length, dactylus with 4 slender spines on lower margin. Pereiopod V (Fig. 22F) basis length 1.2 propodus length. Pereiopod VI (Fig. 22G) similar length to pereiopod VII, basis length 1.3 propodus length. Pereiopod VII (Fig. 22H) length 0.6 body length. Pleopod I (Fig. 24A) length 2.2 pleopod III length; basal segment oval, proximal margin straight, length 1.4 width, inner margin with 6 retinacula, distal segment oval, external margin medially straight, length 1.9 width, margins with 20 simple setae. Pleopod II (Fig. 25A–F), protopod subrectangular, proximal edge rounded, internal margin with 2 simple spines; exopod oval with small cuticular scales on inner and outer margin, exopod margin with 22 plumose setae; endopod slender, curved mesial surface, length 3.2 width, length 0.9 exopod length, length 0.7 protopod length, internal and external processes prominent; endopod apex with 3 processes: cannula short subcylindrical surpassing caudal process, like a semi-rolled sheet; mesial process evident; caudal process robust, subconical, with rounded apex, armed on subapical dorsal surface with 2–17 cuticular scales. Pleopod III (Fig. 24B), exopod oval, length 1.5 width, width 1.6 endopod length, transverse suture in proximal half, 36 plumose setae in distal and proximal margins; endopod subrectangular, length 0.9 exopod length. Pleopod IV (Fig. 24C), exopod length 1.6 width, external proximal margin with incomplete transverse suture, close to pleopod joint; endopod length 0.8 exopod length. Pleopod V (Fig. 24D), exopod oval, length 1.8 width, transverse suture not evident; endopod length 0.9 exopod length, width 0.8 exopod width. Pleotelson (Fig. 24E), subsquare, length 1.0 width, lateral margins parallel, with simple marginal setae, caudomedial lobe produced subacute. Uropods (Fig. 24E), length 0.7 pleotelson length, armed with robust marginal setae, apical endopod setae, exopod length 1.2 endopod length; protopod length 1.1 exopod length. Habitat. This species was located on the shore of the Zacapu lake, between the roots of the aquatic vegetation, in the water lily Eichornia crassipes. Distribution. Known only from the type locality. Etymology. This species is named after the municipality Zacapu, where it inhabits. Remarks. The pleopod IV of Caecidotea zacapuensis sp. nov. is similar to the one of Caecidotea buzwilsoni sp. nov. from Yuriria Lagoon. Both can be differentiated using the transverse suture in pleopod IV: incomplete in Caecidotea zacapuensis sp. nov., and complete in Caecidotea buzwilsoni sp. nov.

Caecidotea buzwilsoni sp. nov. (Figs 6–9) Material examined: Holotype male (CNCR 35528), length 8.0 mm, Laguna de Yuriria, 20°13’11”N, 101°11’05”W, elev. 2275 m, Municipality Yuriria, Guanajuato, Mexico, 22 October 2019, coll. L. García-Vázquez and C. Pedraza-Lara. Paratypes, male (CNCR 35529), length 7.6 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. 15 Males and 10 females (CNCR 35530). Diagnosis. Male body length 3.2 width. Head trapezoidal, width 1.9 length, anterior margin straight; eyes large oval, length 2.0 width. Pleopod IV exopod suture transverse complete. Uropod endopod elongated, oval, length 2.2 width; exopod lanceolate, slender, length 2.7 width. Description. Male (CNCR 35528) 8.0 mm (Fig. 6A); head width 1.9 length, anterior margin concave. Eyes present, oval, dark pigmented, length 2.0 width. Postmandibular lobes not produced. Subrectangular pereionites, ornamented with marginal setae. Pereionite 1 length 1.2 pereionite 2 length; pereionites 6–7 wider, with diagonal margins, widening in posterior angle. Antennula flagellum with 11 articles, longer than distal antenna podomere middle; last four segments with aestetascs in formula 1–1–1–1. Antenna flagellum with 67 articles; proximal article wider than long; following articles increasing in length. Pereiopod I (Figs 6B, 7A), triangular propodus, dactylus curved, propodus palm longer than dactylus; palm with inner and outer edges, ornamented with simple setae; proximal process with 3 robust setae; mesial process acute, not exceeding dactylus width; distal process Subacute length 0.3 mesial process length. Pereiopods II–III (Figs 6C–D), with similar length. Pereiopod IV (Figs 6E, 7B–C), propodus with spine in dactylus; dactylus length 0.6 propodus length, with four spines on lower margin. Pereiopod V (Fig. 6F), basis length 1.3 propodus length. Pereiopod VI (Fig. 6G), similar length to pereiopod VII, basis length 1.2 propodus length. Pereiopod VII (Fig. 6H), length 0.7 body length. Pleopod I (Fig. 8A) length 2.3 pleopod III length; protopod oval, proximal margin straight; protopod 1.7 width, inner margin with 5 retinacula, distal segment subrectangular, outer margin medially straight, length 2.0 width, margins with 23 simple setae. Pleopod II (Fig. 9A–F), protopod subsquare, proximal edge rounded; in dorsal view, exopod base with one distal spine on inner edge, exopod oval with small cuticular scales directed distally on inner dorsal margin, exopod distal margin with 21 plumose setae; slender endopod, with pubescent surface, mesial portion curved, length 3.5 width, similar length to exopod 0.6 protopod length, internal and external process prominent, external with suture close to base, endopod apex with 3 processes: cannula conical, short, with truncated apex lower than caudal process, extending proximally from cannula more than 3.0 its length; mesial process evident; caudal process robust, conical, rounded apex, armed on subapical dorsal surface with 1–17 cuticular scales directed proximally; cuticular scales with pubescence, similar to short villi. Pleopod III (Fig. 8B), exopod oval with distal margin setose, length 1.2 endopod length, width 1.8 endopod width, transverse suture in proximal half, 18 distal plumose setae, external margin 13 simple setae; endopod short oval, length 0.8 exopod length. Pleopod IV (Fig. 8C), exopod oval, as long as 1.9 width, external proximal margin with transverse suture, close to pleopod joint; endopod 0.9 exopod length. Pleopod V (Fig. 8D), exopod oval, length 1.8 width, transverse suture not evident; endopod length 0.9 length, width 0.9 exopod width. Pleotelson (Fig. 8E), subsquare, width 1.2 length, lateral margins parallel, with simple setae, caudomedial lobe broad rounded. Uropods (Fig. 8E), length 0.8 pleotelson length, armed with robust setae; endopod oval, as long as protopod; exopod length 0.9 protopod length. Habitat. This species was collected between roots of the water lily Eichornia crassipes, which floated in a channel of approximately 2 meters wide by one meter deep. Distribution. Known only from the type locality. Etymology. This species is named in honor to Dr. George D. F. Wilson (Buz), Saugatuck Natural History Laboratory, in recognition to his career with the isopods and for being a mentor and for his friendship with the first author. Remarks. Caecidotea buzwilsoni sp. nov. represents the first record of Caecidotea for the Mexican state of Guanajuato. Its morphology is similar to Caecidotea zacapuensis sp. nov. both species can be differentiated by the transverse suture of pleopod IV, which in Caecidotea zacapuensis sp. nov. is incomplete while in Caecidotea buzwilsoni sp. nov. is complete., Published as part of García-Vázquez, Leonardo, Pedraza-Lara, Carlos & Rodríguez-Almaraz, Gabino, 2021, Six new epigean species of Caecidotea (Isopoda: Asellidae) distributed along the Trans-Mexican Volcanic Belt in Central Mexico, pp. 45-77 in Zootaxa 4965 (1) on pages 53-56, DOI: 10.11646/zootaxa.4965.1.2, http://zenodo.org/record/4723078

Caecidotea villalobosi sp. nov. (Figs 18–21) Material examined: Holotype, male (CNCR 35506), length 11 mm; Lago de Catemaco, Coyame, 18°26’12”N, 95°01’27”W, elev. 359 m, Municipality Catemaco, Veracruz, Mexico, 2 November 2017, coll. L. García-Vázquez and C. Pedraza-Lara. Paratypes, male (CNCR 35507), length 10.0 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. 2 males and 3 females (CNCR 35508, CNCR 35509), Laguna Mahahual, 18°39’36”N, 95°18’30W, Municipality San Andrés Tuxtla, Veracruz, Mexico, coll. J. L. Villalobos, E. Moreno and I. Toledano. Diagnosis. Male body 3.2 times longer than wide. Head width 1.4 length, anterior margin concave, lateral margins straight; eyes width 2.1 length, postmandibular lobes not produced; Pereiopod I with dactylus inner edge serrated; dactylus pereiopod IV serrated. Description. Male (CNCR 35506) 11 mm (Fig. 18A); head trapezoidal, head width 1.4 length, anterior margin concave. Eyes present, oval, dark pigmented, width 2.1 length. Postmandibular lobes not produced. Subrectangular pereionites, lateral margins with setae. Pereionite 1 length 0.9 pereionite 2 length; pereionite 1 1.1 pereionite 3 length; pereionites 6–7 with oval margins; posterior widening. Antennula flagellum with 9 articles, longer than distal antenna podomere middle; last four segments with aestetascs with formula 1–0–1–0. Antenna flagellum with 57 articles with pectinate setae; proximal article longer than wide; following articles decreasing in length. Pereiopod I (Figs 18B, 19A–B) dactylus with robust seta on dactylus, inner edge serrated; proximal process with 3 robust setae; acute mesial process not exceeding dactylus width, bicuspid distal process. Pereiopods II– III (Figs 18C–D) similar length. Pereiopod IV (Figs 18E, 19C–D), propodus with robust finger-like projection in dactylus, dactylus length 0.9 propodus length, dactylus serrated. Pereiopod V (Fig. 18F) length basis 1.4 propodus length, dactylus curved hooked. Pereiopod VI (Fig. 18G) smaller than pereiopod VII, basis length 1.3 propodus length, dactylus with spine on lower margin. Pereiopod VII (Fig. 18H) length 0.4 body length. Pleopod I (Fig. 20A) length 1.1 pleopod II length; basal segment oval, proximal margin straight, length 1.3 width, internal margin with 3 retinacula, distal segment oval, outer margin curved in apical portion, length 1.8 width, margins with 12 simple setae. Pleopod II (Fig. 21A–F), protopod subsquare, inner proximal edge straight, with simple short distal seta, dorsal distal edge with cuticular scales; exopod base with spine on right distal border, exopod oval, with rows cuticular scales, distal margin with 15–19 long plumose setae; slender endopod, as long as 3.5 width, exopod length 0.7 protopod length; inner surface curved; internal and external processes prominent, apex with 3 terminal processes: caudal process rounded, cannula short subcylindrical, with a circular apex; mesial process present; endopod subapical portion armed with 14–16 cuticular scales. Pleopod III (Fig. 20B), exopod oval with distal margin setose, length 1.2 endopod length, width 1.9 endopod width, transverse suture in proximal half, 21 marginal plumose setae, external margin with 8 simple setae; endopod oval, 1.2 exopod length. Pleopod IV (Fig. 20C), exopod length 1.5 width, external margin with 4 proximal setae, endopod length 1.1 exopod length. Pleopod V (Fig. 20D), exopod oval, exopod length 1.9 width; external margin with 4 simple setae; transverse suture not evident; endopod notched on outer proximal edge, endopod width 1.2 exopod width. Pleotelson (Fig. 20E), subsquare, width 1.1 length, lateral margins parallel, with simple setae, caudomedial lobe produced subacute. Uropods (Fig. 20F), length 0.7 pleotelson length, armed with robust setae; endopod and exopod lanceolate, endopod length 1.0 exopod length, exopod length 1.1 protopod length. Habitat. The Caecidotea villalobosi sp. nov. specimens were collected on the shore of Catemaco Lake, below rocks submerged in water, as well as on the roots of the water lily Eichornia crassipes. It is important to mention that this species is not abundant in the region. Distribution. Known from the type locality and Laguna Mahahual, San Andrés Tuxtla, Veracruz. Etymology. This species is named after Dr. José Luis Villalobos Hiriart for being an exemplary mentor for the first author and for being an exceptional carcinologist, as well as his contributions to the knowledge of Mexican crustaceans. Remarks. Argano (1977) reported C. communis (Say, 1818) in the Catemaco lake in similar conditions where we collected Caecidotea villalobosi sp. nov., between the roots of a water lily and under submerged rocks on the shore of the lake. Argano mentioned that C. communis has a wide distribution in Mexico and also takes up Bowman’s (1975) hypothesis about an artificial introduction to Mexico due to human action. However, morphological comparisons with the species C. communis sensu Williams (1970), allow it to be clearly distinguished by the following characters: rounded head, anterior margin concave; pleotelson in C. communis is subcircular, as long as wide; caudomedial lobe obtuse produced; pleopod I wider and subrectangular, with 24 simple setae in distal margin, while Caecidotea villalobosi sp. nov. has 12 simple setae. The number of retinacula is 5 in C. communis while Caecidotea villalobosi sp. nov. has 3 retinacula; Regarding the apical elements of the pleopod II endopod, the cannula of C. communis is thin, simple, and elongated, surpassing the distal edge of the caudal process, which lacks cuticular scales. The cannula of Caecidotea villalobosi sp. nov. is short, subcylindrical, does not reach the distal edge of the caudal process and has cuticular scales.

A new freshwater isopod, Caecidotea camaxtli sp. nov. (Isopoda, Asellidae) is described from Mexico. The new species can be distinguished from all other species of Caecidotea by the presence of cuticular scales on the caudal process, as well as a short and simple cannula in the apex of the endopodite of pleopod II. [Zoobank URL: urn:lsid:zoobank.org:act:082CF870-ABC3-4E25-B5F2-8CA59359C2B0]

Mexistenasellus floridensis sp. n. is described from Hole in Wall Cave, Jackson County, Florida. The discovery of this unique isopod nearly doubles the range of the Family Stenasellidae in North America, which was previously known from Oaxaca, Mexico to southern Texas, USA. This is the first stenasellid reported swimming in the water column of a cave, a curious finding for an isopod that belongs to a group that is generally more adapted to inhabiting interstitial spaces. Mexistenasellus floridensis occurs syntopically with the subterranean asellid Caecidotea putea. Both species have been observed swimming in the water column, although neither has apparent anatomical adaptations for swimming as compared to the natatory pereopods of Remasellus parvus, an asellid that occurs in caves in Alachua, Madison and Wakulla counties, Florida.

Caecidotea mausi Lewis & Bowman, 2009 (in Lewis 2009) (Figs 1, 5 i) Range. This obligate subterranean species is known from two caves about 80 km apart in Washington Co., Maryland and adjacent Warren Co., Virginia (Lewis, 2009)., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on page 62, DOI: 10.5281/zenodo.207750, {"references":["Lewis, J. J. (2009) Three new species of Caecidotea, with a synopsis of the asellids of Virginia (Crustacea: Isopoda: Asellidae). Virginia Museum of Natural History Special Publication No. 16, 245 - 259."]}

Caecidotea vandeli (Bresson, 1955) (Figs 1, 5 g, 6) Material examined. MARYLAND: Frederick Co., Gum Spring, Brunswick Town Park, DJF, 16 April 1994, 33, 2 ��; Montgomery Co.: Edwards Ferry Spring # 11, 0.65km NE from mouth of Goose Creek, C& O NHP, DJF, 26 March 1996, 131��; northeast spring, Three Spring Hollow, C& O Canal, DJF, 1 April 1994, 13; same, southwest spring, 33, 3 ��; Washington Co.: Roundtop Hollow Mine # 2, DJF, 1 May 1992, 13; same locality, DJF, R. Bartgis, 11 June 1993, 23; spring # 1, Seneca Creek State Park, DJF, C. Lee, 16 March 1994, 53, 6 ��. Range. This species has been reported from seven counties in Virginia (Holsinger & Culver 1988; Lewis 2009). Similar to C. pricei, this species has dispersed from the Appalachians into the Piedmont. The relatively wide range of this species is probably related to its ability to disperse through non-cave groundwaters., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on page 63, DOI: 10.5281/zenodo.207750, {"references":["Bresson, J. (1955) Un asellide nouveau de l'Amerique du Nord. Archives de Zoologie Experimentale et Generale, Notes et Revue, 94, 37 - 43.","Holsinger, J. R. & Culver, D. C. (1988) The invertebrate cave fauna of Virginia and a part of eastern Tennessee. Brimleyana, 14, 1 - 162.","Lewis, J. J. (2009) Three new species of Caecidotea, with a synopsis of the asellids of Virginia (Crustacea: Isopoda: Asellidae). Virginia Museum of Natural History Special Publication No. 16, 245 - 259."]}

Caecidotea kenki (Bowman, 1967) (Figs 5 c, 6) Material examined. MARYLAND: Allegany Co., Cresatown, small stream behind high school, AN, 5 January 1980, 20��; Cumberland Blue Spring, DJF, 10 March 1989, 13��; Pinto Mine, deep pool of water in mine shaft, DJF, D. Grove, 29 July 1987 13; Potomac Blue Hole Spring, DJF, 9 June 1988, 53; Red Hill spring, DJF 26 May 1988, 232��; small spring, Dan���s Mountain, DJF, ET, no date, 237 ��; small spring feeding Murley Branch, DJF, 13 February 1988, 4��; two springs near Pinto Mine, DJF, 1 April 1988, 5��; Garrett Co.: spring near Junction of Westernport & Russell roads, AN, 16 August 1981, 52��; Bear Creek springs, DJF, 14 July 1989, 133��; Little Bear Creek springs, DJF, 12 July 1989, 9��; small spring fed pool in sandstone shelter, DJF, 5 March 1988, 131��; spring on north side of Salt Block Run, DJF, 15 February 1988, 19��; spring, unnamed tributary of Lower Savage River, DJF, 17 June 1991, 23, 2 ��; The Glades Spring, DJF, 22 May 1992, 6��; Vansicles Rock Spring, DJF 27 May 1992, 131��; Wolf Swamp spring, DJF., 10 June 1991, 10��; Montgomery Co.: spring at end of Susan Lane feeding Ruck Creek J. Hill, J. Royte, 13 April 1990, 82��; spring in Glen Echo Heights Quarry, DJF, 9 March 1996, 13; Washington Co.: Big Spring, DJF, 23 July 1988, 7��; Canal Culvert Spring, DJF, 14 April 1993, 3��; Cedar Grove Spring # 1, DJF, 14 April 1993, 4��; Flatworm Spring, DJF 19 April 1993, 5��; Indian Spring, DJF, 19 March 1989, 15��; Karst Window Spring, DJF 20 April 1993, 3��; Keedysville Spring, DJF, 23 July 1988, 20��; Lime Mill Spring, DJF, 29 April 1992, 23, 2 ��; Roundtop Hollow Spring, DJF, R. Bartgis, 11 June 1993, DJF, R. Bartgis, 1 ��; Roundtop Siding springs, DJF, no date, 4 ��. Range. This species is an inhabitant of springs and has been recorded from northern Virginia, the District of Columbia, Maryland and Pennsylvania (Bowman 1967). It is sympatric with C. alleghenyensis in western Maryland, but no cases of co-occurrence have yet been recorded. As noted by Lewis (2009), some populations (e.g., Glen Echo Springs) are stygomorphic., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on pages 61-62, DOI: 10.5281/zenodo.207750, {"references":["Bowman, T. E. (1967) Asellus kenki, a new isopod crustacean from springs in the eastern United States. Proceedings of the Biological Society of Washington, 80, 131 - 140.","Lewis, J. J. (2009) Three new species of Caecidotea, with a synopsis of the asellids of Virginia (Crustacea: Isopoda: Asellidae). Virginia Museum of Natural History Special Publication No. 16, 245 - 259."]}

Caecidotea nordeni Lewis & Bowman, 2010 (Figs 1, 5 d) Range. This species is known only from the type-locality, a spring stream near Ernstville, in Washington Co., Maryland. The eyeless, unpigmented appearance of this isopod indicates that it is a subterranean species, presumably discharged into the spring stream in which it was collected. Numerous attempts to find it again have been unsuccessful., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on page 62, DOI: 10.5281/zenodo.207750, {"references":["Lewis, J. J. (2010) The subterranean asellids of Maryland: Description of Caecidotea nordeni, new species, and new records of C. holsingeri and C. franzi ((Crustacea: Malacostraca: Asellidae). Journal of Cave and Karst Studies, 72, 100 - 104."]}

Caecidotea alleghenyensis Lewis & Bowman, new species (Figs 1���4, 5 a���b, 6) Material examined. MARYLAND: Garrett Co., Holotype: 8.8 mm 3, Swallow Falls State Park, spring # 1, Daniel J. Feller (DJF), 20 May 1992 (USNM 1138994). Paratypes: 113, 3 ��, same data as holotype (USNM 1138995). Other material: Spring 35 meters south of Swallow Falls Road, opposite entrance to Maple Glade Road, A. W. Norden (AWN), B. Norden, 17 September 1978, 35�� (USNM 1138996); springs feeding Deep Creek along west side of Oakland-Sang Road, E. Thompson (ET), 4 April 1986, 13, 4 �� (USNM 1138997); spring flowing into tributary of Herrington Run, DJF, ET, 15 May 1987, 113, 3 �� (USNM 1138998); same locality, DJF, 16 May 1987, 233�� (USNM 1138999); spring between Herrington Manor Road & Zenas Mellott Road, outlet 0.2 mile [0.3km] SE of Junction, Swallow Falls State Forest, DJF, 17 May 1987, 23 (USNM 1139000); springs between Herrington Manor Road & Zenas Mellott Road, outlets 0.3, 0.5 and 0.7 mile [0.5, 0.8 and 1.1km] SE of Junction (3 vials), Swallow Falls State Forest, DJF, 20 May 1987, 33 (USNM 1139001); 334 �� (USNM 1139002); 233 �� (USNM 1139003); spring flowing into tributary of Chisolm Run 1.1 [1.8km] miles east of Hutton (2 vials), DJF, ET, 17 June 1987, 537�� (USNM 1139004); 734 �� (USNM 1139005); spring below John Friend Cave, DJF, 3 March 1988, 33, 5 �� (USNM 1139006); spring flowing into Sang Run, DJF, 5 March 1988, 13, 1 ��; Herrington Run Spring Complex, DJF, 11 May 1988, 13 (USNM 1139007); spring along Deep Creek, ca. 0.3 miles [0.5km] W Oakland-Sang Run Road, DJF, 4 October 1989, 534�� (USNM 1139008); spring at confluence of Muddy Creek and Youghiogeny River, AN, 29 August 1993, 43, 4 �� (USNM 1139009); Swallow Falls spring, AWN, 29 August 1993, 36�� (USNM 1139010). Diagnosis. Member of the hobbsi Group of Caecidotea (Lewis 1982, 2009), with male gnathopod propodus armed with well developed processes. Pleopod 1 exopod with plumose setae along distal margin. Pleopod 2 endopod tip with cannula extending parallel to the axis of the endopod, obscured by broadly rounded mesial process and smaller lateral process. Uropods shorter than pleotelson. Description of male. Longest to 9 mm, approximately 3.6X as long as wide. Body appears unpigmented to naked eye, dorsum of head and pereonites with light diffuse pigmentation under low magnification, most pronounced on head, then decreasing progressively from pereonites 1���4. Eyes small, but distinct and pigmented. Margins of head, pereonites and pleotelson densely setose. Head approximately 1.8X as wide as long, pleotelson moderately produced. Pleotelson slightly longer than wide. Antenna 1 extending to middle of last article of antenna 2 peduncle, flagellum to 10 articles, distal 3 each with 1 esthete. Antenna 2, penultimate article of peduncle about 2 / 3 length of distal article, flagellum to 50 articles, reaching to pereonite 7 when bent. Mouthparts per diagnosis of genus (Lewis 2009). Pereopod 1, propodus 1.4X as long as wide, palmar margin proximally with low, stout setae, mature adult with large blade-shaped median process extending well beyond outer margin of recumbent dactyl, distal bicuspid process lower in height relative to median process. Pleopod 1, protopod approximately 0.6X length of exopod, with 3 retinacula. Exopod approximately 2 X as long as wide, lateral margin weakly concave, 3 very elongate plumose setae along distal margin. Pleopod 2, exopod distal article with approximately 20 + elongate plumose setae along margins. Endopod with rounded basal apophysis of varying prominence, tip with 4 processes in anterior view: (1) cannula low, conical, obscured; (2) mesial process broadly rounded, (3) lateral process similar to mesial process, lower and smaller; (4) caudal process broadly rounded forming apex of endopod. Pleopod 3 exopod, proximolateral margin with non-plumose setae, distolateral and apical margin with plumose setae increasing in size toward apical margin. Pleopod 4 exopod with transverse false suture, proximolateral margin with numerous non-plumose setae of moderate length. Pleopod 5 exopod, proximolateral margin with 3 non-plumose elongate setae. Uropods 0.75 length of pleotelson, protopod spatulate, about equidistant in length with endopod, exopod 0.75X length of endopod. Etymology. The name refers to the Allegheny Mountains. The suggested vernacular name is the Allegheny spring isopod. Range. Known only from the Allegheny Mountains of western Maryland. Ecological notes. This species is known only from springs, where it was found associated with leaf litter and decaying wood. Ovigerous females were present in collections from May and June, and ranged in size from 3.8 to 6.2 mm in length., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on pages 55-61, DOI: 10.5281/zenodo.207750, {"references":["Lewis, J. J. (1982) A diagnosis of the hobbsi Group, with descriptions of Caecidotea teresae, n. sp., and C. macropropoda Chase and Blair (Crustacea: Isopoda: Asellidae). Proceedings of the Biological Society of Washington, 95 (2), 338 - 346.","Lewis, J. J. (2009) Three new species of Caecidotea, with a synopsis of the asellids of Virginia (Crustacea: Isopoda: Asellidae). Virginia Museum of Natural History Special Publication No. 16, 245 - 259."]}

Caecidotea franzi (Holsinger & Steeves, 1971) (Figs 1, 5 f, 6) Material examined. MARYLAND: Allegany Co., Fort Hill Spring, AWN, 27 June 1985, 33, 2 ��; same locality, DJF, 23 June 1990, 63, 3 ��; Pinto Mine, deep pool of water in mine shaft, DJF, D. Grove, 29 July 1987, 1312��. WEST VIRGINIA: Mineral Co., Kites Cave, DJF, 11 June 1992, 23, 6 ��. Range. This species occurs in western Maryland and adjacent West Virginia, with disjunct populations in Centre Co., Pennsylvania and Harlan Co., Kentucky (Lewis 2010)., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on page 61, DOI: 10.5281/zenodo.207750, {"references":["Holsinger, J. R. & Steeves, H. R. (1971) A new species of subterranean isopod crustacean (Asellidae) from the central Appalachians, with remarks on the distribution of other Isopods in the region. Proceedings of the Biological Society of Washington, 84,189 - 200.","Lewis, J. J. (2010) The subterranean asellids of Maryland: Description of Caecidotea nordeni, new species, and new records of C. holsingeri and C. franzi ((Crustacea: Malacostraca: Asellidae). Journal of Cave and Karst Studies, 72, 100 - 104."]}

Caecidotea pricei Levi, 1949 (Figs 1, 5 e, 6) Material examined. MARYLAND: Cecil Co., Folks Pond Spring, DJF, 14 April 2010, 434��; Montgomery Co., Chilton Woods Spring # 8, DJF, 15 April 1994, 133��; Chilton Woods Spring # 9, DJF, 15 April 1994, 336��; Chilton Woods Spring # 10, DJF, 15 April 1994, 332��; Washington Co., Antietam Quarry Spring, DJF, 13 April 1993; 4 ��; Artz Cave, DJF, 17 June 1992, 13; Canal Culvert Spring, DJF, 14 April 1993, 3��; Cedar Bluff Spring, DJF, 29 April 1992, 6��; Dargan Seep # 2, DJF, 13 April 1992, 8��; Dargan Spring, DJF, 13 April 1993, 10��; Dellinger Culvert Spring, DJF, R. Bartgis, 28 April 1993, 4��; Flatworm Spring, DJF 19 April 1993, 6��; Hagerstown City Park Pond Springs, DJF, 11 Oct 1989, 3��; Howell Cave, DJF, 23 June 1989, 2��; Karst Window Spring, DJF 20 April 1993, 8��; Kemps Spring # 1, DJF 28 March 1989, 4��; Kemps Spring # 2, DJF, 28 March 1989, 235��; Kemps Spring # 3, DJF, 28 March 1989, 10 ��; Lime Mill Spring, DJF, 29 April 1992, 3��; Neck Bluff Spring # 1, DJF, R. Bartgis, 28 April 1993, 2��; Neck Bluff Spring # 2, DJF, R. Bartgis, 28 April 1993, 8��; Neck Spring near Falling Waters Road, DJF, 22 March 1989, 233��; Quarry Spring, DJF, 5 February 1992; 5 ��; Sump Spring, DJF, R. Bartgis, 28 April 1993, 9��; Two Locks Spring # 2, DJF, 28 April 1992, 131��; Watercress Pool Spring, DJF, 29 April 1992, 23; Williamsport Spring, DJF, 28 March 1989, 123. Range. As indicated by the records above, this is the predominant stygobiotic Caecidotea in the Ridge and Valley region of Maryland. It occurs in Virginia and adjacent West Virginia, through Maryland into Pennsylvania. In the latter two states C. pricei has crossed the Blue Ridge into the Piedmont (Steeves 1969; Lewis 2009)., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on pages 62-63, DOI: 10.5281/zenodo.207750, {"references":["Levi, H. (1949) Two new species of cave isopods from Pennsylvania. Notulae of the Academy of Natural Sciences of Philadelphia, 220, 1 - 6.","Steeves, H. R. (1969) The origin and affinities of the troglobitic asellids of the southern Appalachians. Pages 51 - 65, in P. C. H olt (editor), The distribution history of the biota of the southern Appalachians. Part 1. Invertebrates. Virginia Polytechnic Institute and State University, Research Division Monograph 1.","Lewis, J. J. (2009) Three new species of Caecidotea, with a synopsis of the asellids of Virginia (Crustacea: Isopoda: Asellidae). Virginia Museum of Natural History Special Publication No. 16, 245 - 259."]}

Caecidotea mausi Lewis & Bowman, 2009 (in Lewis 2009) (Figs 1, 5 i) Range. This obligate subterranean species is known from two caves about 80 km apart in Washington Co., Maryland and adjacent Warren Co., Virginia (Lewis, 2009).

Caecidotea holsingeri (Steeves, 1963) (Figs 1, 5 h, 6) Material examined. MARYLAND: Garrett Co., John Friend Cave, DJF, D. Hubbard, 29 August 1992, 33. Range. Summarized by Lewis (2009, 2010) and Fong et al. (2009) this species occurs primarily in caves from southwestern Virginia through eastern West Virginia, to Garrett Co., Maryland., Published as part of Lewis, Julian J., Bowman, Thomas E. & Feller, Daniel J., 2011, A synopsis of the subterranean asellids of Maryland, U. S. A., with description of Caecidotea alleghenyensis, new species (Crustacea: Isopoda: Asellota), pp. 54-64 in Zootaxa 2769 on page 61, DOI: 10.5281/zenodo.207750, {"references":["Steeves, H. R. (1963) Two new species of troglobitic asellids from West Virginia. American Midland Naturalist, 70 (2), 462 - 465.","Lewis, J. J. (2009) Three new species of Caecidotea, with a synopsis of the asellids of Virginia (Crustacea: Isopoda: Asellidae). Virginia Museum of Natural History Special Publication No. 16, 245 - 259.","Lewis, J. J. (2010) The subterranean asellids of Maryland: Description of Caecidotea nordeni, new species, and new records of C. holsingeri and C. franzi ((Crustacea: Malacostraca: Asellidae). Journal of Cave and Karst Studies, 72, 100 - 104.","Fong, D. W., Culver, D. C., Hobbs, H. H. & Pipan, T. (2009) The invertebrate cave fauna of West Virginia, Second edition. West Virginia Speleological Society Bulletin, 16, 163 pp."]}

Nine species of asellid isopods are reported from groundwater habitats in Maryland. Three of these species are habitually found in springs: Lirceus brachyurus, Caecidotea kenki, and C. alleghenyensis, n. sp. The latter, described herein, is a member of the hobbsi group known only from the Allegheny Mountains in Garrett Co. Six species are obligate inhabitants of subterranean waters and are found primarily in Appalachian caves, although some have broad ranges that span noncavernous areas. The obligate subterranean species are Caecidotea pricei, C. franzi, C. holsingeri, C. mausi, C. vandeli and C. nordeni.