Craugastor cueyatl, Jameson & Streicher & Manuelli & Head & Smith, 2022

Jameson, Tom J. M., Streicher, Jeffrey W., Manuelli, Luigi, Head, Jason J. & Smith, Eric N., 2022, Miniaturization in Direct-Developing Frogs from Mexico with the Description of Six New Species, Herpetological Monographs 36 (1), pp. 1-48 : 23-25

Craugastor cueyatl sp. nov.

Microbatrachylus hobartsmithi: Duellman 1961:33 (in part, based on field IDs EHT-HMS Nos. 18292–18352, includes CAS 87816). [Misidentification].

Eleutherodactylus hobartsmithi: Castro-Franco et al. 2006:107 . [Misidentification].

Holotype. — UTA A-62348 (field ID: JAC 27244; Fig. 24B ), male collected by J.W. Streicher, C.L. Cox, J. ReyesVelasco, G. Weatherman, and C.M. Sheehy, III, on the road from Avandaro to El Manzano , East of Cerro Gordo , Estado de México, Mexico, 19.12209°N, 100.13969°W, 2311 mon 18 June 2008 .

Paratypes (2). —MZFC-HE-35614 ( Fig. 24A ), female with developed ova covered in mildly pigmented connective tissue, same data as holotype, except 19.11735°N, 100.13940°W, 2282 m. AMNH A- 57809 ( Fig. 24 C ), male from Tepozteco, Morelos, Mexico ( Aztec archaeological site, 19.00079°N, 99.10156°W, 2000 m) .

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Referred specimens (4). — USNM 122054–55, and USNM 139380 from Estado de México and Morelos, respectively. MZFC 1089, from Tepoztlán, Barrio de Ixcaltepec, central Morelos.

Diagnosis. —A species of Craugastor distinguished by the following combination of characters: (1) small adult size (maximum SVL ¼ 15.7 mm); (2) reduced ossification of the skeleton relative to other members of the series, lacking ossification of any skeletal elements beyond Stage 2 ( Table 3 ); (3) presence of posterolateral projection of frontoparietal; (4) absence of vomerine odontophores; (5) presence of raised tubercles on eyelids; (6) supratympanic fold absent or poorly developed; (7) face flank barred, with snout–nostril– canthal–supratympanic stripe; (8) on postrictal tubercle; (9) gular region lightly pigmented; (10) dorsal surface unicolored dark; (11) dark middorsal ridge; (12) evenly tubercular dorsum; (13) body flank unicolored pale with or without a dark supra- or postaxillary band, shagreened; (14) inguinal glands present and axillary glands absent in adults; (15) when leg adpressed to body, heel reaches anterior corner of eye; (16) outer tarsal ridge with 3–7 rounded tubercles, no raised fringe; (17) finger tips round and not expanded, toe tips slightly lanceolate and barely expanded; (18) similar sizes of inner and outer metatarsal tubercles.

Comparisons. — Craugastor cueyatl can be differentiated from C. candelariensis , C. mexicanus , C. montanus , C. omiltemanus , C. portilloensis , and C. saltator by the presence of vomerine odontophores (absent in C. cueyatl ). It can be differentiated from C. bitonium , C. hobartsmithi , C. polaclavus , and C. pygmaeus by the absence of posterolateral projections of the frontoparietal (present in C. cueyatl ). It can be differentiated from C. rubinus by a larger inner metatarsal tubercle than outer metatarsal tubercle (inner and outer metatarsal tubercles are similar sizes in C. cueyatl ).

Description of the holotype. — Holotype small male (SVL ¼ 12.3 mm); highly pigmented testes; snout rounded and short (0.6 mm naris–snout; 4% SVL); medium eye– nostril distance (1.4 mm; 11% SVL); tympanum 1.2 mm (10% SVL); supratympanic fold terminating in small shoulder tubercle; finger length formula III <IV <II <I; single palmar tubercle; single prepollical tubercle; subarticular tubercles present on all fingers; supernumerary tubercles not present on hand; left arm removed for genetic analysis; toe length formula IV <III <V <II <I; inner metatarsal tubercle and outer metatarsal tubercle equal in size; subarticular tubercles present on all toes; supernumerary tubercles present on plantar surface; small supracloacal fold; 1–2 bands of melanocytes on remaining arm; bands on legs evident in life barely visible in preserved specimen.

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Variations in paratypes. —Body sizes (SVL) 15.7 mm (MZFC-HE-35614), 11.7 mm (AMNH A-57809); eye–nostril distance 7% SVL (female), unavailable (male); tympanic ratios 8% (female), 11% (male); crus ratio 51% (female), 54% (male).

Etymology. —The specific epithet is taken from the word for frog in Nahuatl, an Aztec language that has been spoken in the Valley of Mexico since the 7th century, a region that includes the type locality of C. cueyatl .

Distribution. —The new species occurs throughout the central region of the Trans Volcanic Mexican Cordilleras slopes, those facing the Río Balsas, in the states of Mexico and Morelos (1670–2264 m), an area of mesic pine–oak forest habitat. Castro-Franco et al. (2006) associated C. cueyatl (as E. hobartsmithi ) with dry tropical forests and cultivated areas.

Diet. —The holotype’s stomach was found to contain a small spider of unknown taxonomy.

Phylogenetics. — Craugastor cueyatl was inferred to be the sister taxon of C. bitonium þ C. pygmaeus with strong support in the concatenated analysis (87 ML; 0.99 BAYES; Fig. 3 ). The placement of C. cueyatl was less certain in the mtDNA and nDNA-only analyses ( Figs. 4 and 5 ). In terms of genetic distances, Craugastor cueyatl is most similar to C. pygmaeus (5.9%; Table 4 ).

Remarks. —The skull of C. cueyatl is similar to that of C. hobartsmithi , C. montanus , and C. pygmaeus with a more posteriorly placed anterior suture of the frontoparietal and prootic than in other species. Several of the referred specimens are based on geographic occurrence and general gestalt and should be further examined. One referred specimen of C. cueyatl (USNM 139380) is reported to be collected from Distrito Federal (¼ Mexico City). We georeferenced this locality as being in the city ( Fig. 8 ), but it is most likely the specimen was collected from outside the metropolis. Very rarely do species of vertebrate occurring near or in major metropolitan areas remain hidden from science; the late discovery of this new species is likely explained by the diminutive size of C. cueyatl and previous confusion with C. hobartsmithi and C. pygmaeus .

Figures

FIG. 24.—Female paratype (A, MZFC-HE-35614, SVL ¼ 15.8 mm) and male holotype (B, UTA A-62348, SVL ¼ 12.3 mm) of Craugastor cueyatl from type locality; male paratype (C, AMNH A-57809, SVL ¼ 11.7 mm) from Tepozteco, Morelos, Mexico, ~2000 m (C). Leaf litter habitat near the type locality east of Cerro Gordo, Estado de México, Mexico, 2282 m (D).

FIG. 3.—Concatenated Maximum Likelihood analyses of two mitochondrial (12S and 16S) and two nuclear (RAG1 and TYR) gene fragments sequenced from the Craugastor mexicanus series (total of 2230 base pairs). Node values correspond to bootstrap support from Maximum Likelihood analysis and posterior probabilities from a Bayesian analysis of the same data set, respectively. Support values are not reported for nodes that had,50/0.50. NS indicates no support in the Bayesian analysis for a depicted relationship. Locality abbreviations are as follows: COL ¼ Colima, HID ¼ Hidalgo, GRO ¼ Guerrero, JAL ¼ Jalisco, MEX ¼ Estado de México, OAX ¼ Oaxaca, PUE ¼ Puebla, and VER ¼ Veracruz.

FIG. 4.—Maximum Likelihood analyses of mitochondrial DNA (mtDNA) markers sequenced from the Craugastor mexicanus series (total of 1047 base pairs). Black circles indicate nodes receiving bootstrap support values.90 from the Maximum Likelihood analysis and 0.90 posterior probabilities in corresponding Bayesian analyses. Where posterior probabilities were.0.90 but Maximum Likelihood bootstrap support was,90, a number indicates the bootstrap support. NS indicates no support in the Bayesian analysis for a depicted relationship. Locality abbreviations are as follows: COL ¼ Colima, HID ¼ Hidalgo, GRO ¼ Guerrero, JAL ¼ Jalisco, MEX ¼ Estado de México, OAX ¼ Oaxaca, PUE ¼ Puebla, and VER ¼ Veracruz.

FIG. 5.—Maximum Likelihood analysis of nuclear DNA (nDNA) markers sequenced from the Craugastor mexicanus series (total of 1183 base pairs). Black circles indicate nodes receiving bootstrap support values.90 from the Maximum Likelihood analysis and 0.90 posterior probabilities in corresponding Bayesian analyses. Where posterior probabilities were.0.90 but Maximum Likelihood bootstrap support was,90, a number indicates the bootstrap support. NS indicates no support in the Bayesian analysis for a depicted relationship. Locality abbreviations are as follows: COL ¼ Colima, GRO ¼ Guerrero, JAL ¼ Jalisco, MEX ¼ Estado de México, OAX ¼ Oaxaca, PUE ¼ Puebla, and VER ¼ Veracruz.

FIG. 8.—Distribution of Craugastor hobartsmithi, C. cf. hobartsmithi, C. omiltemanus and six new species from Mexico. Dots inside symbols indicate individuals used in the molecular analyses in this study. Inset depicts region of Oaxaca where three of the new species exist in near sympatry. A question mark indicates uncertain georeferencing. Relevant type localities are indicated by text and arrows.