Craugastor omiltemanus ( Günther 1900a )

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 : 30-31

Craugastor omiltemanus ( Günther 1900a)

Syrrhaphus omiltemanus Günther 1900 a:213 . Holotype unsexed ( BMNH 1901.12.19.7) from ‘‘Omilteme, Guerrero, Mexico.’’ [Examined] .

Hylodes calcitrans Günther 1900 b:229 . Holotype unsexed ( BMNH 1901.12.19.25) from ‘‘Omilteme, Guerrero, Mexico.’’ [Examined] .

Eleutherodactylus omiltemanus (Günther) : Lynch 1970:175.

Craugastor omiltemanus (Günther) : Crawford and Smith 2005:536.

Diagnosis. —Based on Hylodes calcitrans type series of 25 individuals and 1 additional specimen. Aspecies of Craugastor distinguished by the following combination of characters: (1) large adult size (maximum SVL ¼ 38.8 mm); (2) reduced ossification of skeleton in adults relative to other members of series, lacking ossification of any elements beyond Stage 2 ( Table 3 ) except for the sphenethmoid; (3) presence of posterolateral projection of frontoparietal; (4) presence of vomerine odontophore; (5) presence or absence of raised tubercles on eyelids, smooth, six round and only slightly protruding tubercles, sometimes a few aligned at the outer edge; (6) supratympanic fold developed; (7) face flank barred or dark; canthus dark, pale, or spotted; canthus with or without a stripe (complete or broken); (8) one or two postrictal tubercles; (9) gular region from evenly scattered fine pigmentation, to densely pigmented with a mid-pale stripe; (10) dorsal surface unicolored pale brown or grey; unicolored to lightly spotted above the scapular and/or rump areas, or tubercles and ridges (if present), interorbital bar; (11) with or without a middorsal ridge; (12) dorsum smooth with only few fine tubercles toward flanks and urostyle or with ridges forming hourglass patterns and medium tuberculation; (13) body flank darker anteriorly (postaxillary) due to posterolateral expansion of supratympanic stripe; sometimes with contrasting white and dark blotching inguinal area, otherwise pale colored; shagreened; (14) inguinal gland present and axillary gland present in adults; (15) when leg adpressed to body, heel reaches middle of eye to mid-canthal area; (16) outer tarsal ridge 0–5 rounded and only slightly raised tubercles, no raised fringe; (17) finger and toe pads round, fingertips slightly or not expanded, toe tips expanded; (18) inner metatarsal tubercle larger than outer metatarsaltubercle.

Comparisons. — Craugastor omiltemanus can be differentiated from all other members of the C. mexicanus series by the combination of rough (and often raised) areolate skin on its venter and a massive inner metatarsal tubercle ( Figs. 21G and 29 ; Lynch 1970, 2000).

Description. —In previous literature described as largebodied, short-legged, with Toe III <Toe V; innermetatarsal tubercle up to five times larger than outer metatarsal tubercle ( Fig. 29A ); subarticular tubercles conical; vomerine odontophores; few supernumerary plantar tubercles ( Taylor 1941; Lynch 2000).

There are two syntypes of C. omiltemanus, BMNH 1901.12.19.7 (reregistered as BMNH 1947.2.16.62; Fig. 1 J ) and BMNH 1901.12.19.8 (reregistered as BMNH 1947.2.16.63). We designate the former as the lectotype and the latter as the paralectotype of this species. Both specimens appear to have partially desiccated at some point in their history, whereas the type series of Hylodes calcitrans is in much better condition ( Fig. 1K ; Fig. 23A and B ). We designate BMNH 1901.12.19.29 (reregistered as BMNH 1947.2.16.47) as the lectotype of H. calcitrans . Relative finger lengthsof the typesare III> IV> II> Iandrelative toe lengths are IV <III <V <II <I. Dorsal skin texture raised, often with an Xpattern of sebaceous glands in life ( Fig. 30A–D ).

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Distribution. —Prior to our study, C. omiltemanus was known only from Guerrero ( Günther 1900a; Crawford and Smith 2005). Our discovery of a specimen from Oaxaca (UTA A-64264) that is both phylogenetically and morphologically assignable with C. omiltemanus extends the distribution of this species eastward. This species occurs in high-elevation pine–oak forest habitats of the Sierra Madre del Sur in the states of Guerrero and Oaxaca ( Fig. 8 ; Fig. 30E and F ).

Phylogenetics. —In all analyses, C. omiltemanus was found to be monophyletic with strong support (ML> 90; BAYES> 0.90; Figs. 3 and 4 ). In the concatenated analysis C. omiltemanus was found to be the sister taxon of C. saltator , although with limited support (ML ¼ 44; BAYES ¼ 0.74; Fig. 3 ). There was less support for the sister relationship with C. saltator in the mtDNA-only analysis (ML ¼ 33; BAYES ¼ 0.82; Fig. 4 ). In the nDNA-only analysis (which did not include C. saltator ), C. omiltemanus was placed in basal polytomy with two other clades: (1) C. mexicanus and (2) all other species of the C. mexicanus series ( Fig. 5 ). In terms of genetic distances ( Table 4 ), C. omiltemanus was most similar to C. mexicanus (4.9%), followed by similarity to C. saltator (5.6%).

Remarks. —The skull of C. omiltemanus is similar to C. mexicanus and C. saltator with a more anteriorly placed anterior suture of frontoparietal and prootic than that in other species. Skull examination also was conducted on a smaller subadult individual (UTA A-55240, SVL ¼ 16.5 mm) that had only Stage 1 of the ontogenetic sequence complete and only two features of Stage 2 present. Unlike the adult specimen, the nasals are completely unossified and the frontoparietal greatly reduced, and while vomerine odontophores are present the posterolateral projection of the frontoparietal is absent. Craugastor omiltemanus likely shares a similar distribution with other Craugastor species endemic to the Sierra Madre del Sur (e.g., C. uno ; Streicher et al. 2011). Lynch (2000) reports that C. omiltemanus has white testes, but we observed pigmented testes in this species ( Table 5 ). Throughout its range, C. omiltemanus likely co-occurs with C. bitonium , C. mexicanus , C. pygmaeus , and C. saltator . Male C. omiltemanus have significantly larger tympana than do female C. omiltemanus ( Lynch 2000; this study).

Figures

FIG. 21.—Ventral surface of the foot in representative specimens of the Craugastor mexicanus series. Female paratype of C. bitonium (A, UTA A-66118, SVL ¼ 16.7 mm); female paratype of C. candelariensis (B, UTA A-55247, SVL ¼ 18.6 mm); female paratype of C. cueyatl (C, MZFC-HE-35614. SVL ¼ 17.2 mm); male C. hobartsmithi (D, UMMZ 94231, SVL ~11 mm, photo by J. David Curlis); male C. mexicanus (E, UTA A-6907, SVL ¼ 22.3 mm); male Craugastor montanus (F, UMMZ 88002, SVL ¼ 21.8 mm); male C. omiltemanus (G, UTA A-66139, SVL ¼ 18.1 mm); female holotype of C. polaclavus (H, UTA A-62392, SVL ¼ 14.7 mm); female paratype of C. portilloensis (I, MZFC-HE-35581, SVL ¼ 12.1 mm); female C. pygmaeus (J, UTA A-54809, SVL ¼ 17.3 mm); male paratype of C. rubinus (K, MZFC-HE-35616, SVL ¼ 10.8 mm); female C. saltator (L, UTA A-55239, SVL ¼ 38.2 mm). A color version of this figure is available online.

FIG. 29.—Ventral coloration and areolate skin texture of Craugastor omiltemanus. Venter in preservative, an arrow indicates the large inner metatarsal tubercle that is characteristic of the species (A, BMNH 1947.2.16.44, SVL ¼ 36.5 mm, photo by W.-Y. Cooper); venter in preservative (B, BMNH 1947.2.16.47, SVL ¼ 39.6 mm, photo by W.-Y. Cooper); venter in life (C, UTA Field ID: JAC 27695); venter in life (D, UTA Field ID: JAC 27694). A color version of this figure is available online.

FIG. 1.—Male holotype of Eleutherodactylus hobartsmithi Taylor (A, FMNH 100114, SVL ¼ 14.4 mm); female holotype of Leiuperus mexicanus Brocchi (B, MNHNP 6318, SVL ~ 40 mm); male holotype of Microbatrachylus oaxacae Taylor (C, FMNH 100001, SVL ¼ 18.1 mm); male holotype of Microbatrachylus lineatissimus Taylor (D, FMNH 100036, SVL ¼ 20.0 mm); female holotype of Microbatrachylus montanus Taylor (E, USNM 115507, SVL ¼ 27.0 mm); female holotype of Eleutherodactylus pygmaeus Taylor (F, UIMNH 16125, SVL ¼ 17.0 mm); female holotype of Microbatrachylus albolabris Taylor (G, FMNH 100071, SVL ¼ 16.5 mm); male holotype of Microbatrachylus minimus Taylor (H, FMNH 100323, SVL ¼ 15.0 mm); female holotype of Microbatrachylus imitator Taylor (I, USNM 115508, SVL ¼ 14.2 mm); male lectotype of Syrrhaphus omiltemanus Günther (J, BMNH 1947.2.16.62, SVL ¼ 19.8 mm); female lectotype of Hylodes calcitrans Günther (K, BMNH 1947.2.16.47, SVL ¼ 34.9 mm); female holotype of Eleutherodactylus saltator Taylor (L, FMNH 100166, SVL ¼ 44.0 mm). Symbols correspond to current taxonomic assignments (square ¼ C. hobartsmithi, triangle ¼ C. mexicanus, crossedsquare ¼ C. montanus, pentagon ¼ C. omiltemanus, circle ¼ C. pygmaeus, rotated-triangle ¼ C. saltator). A color version of this figure is available online.

FIG. 23.—Male paratype of Craugastor candelariensis (MZFC-HE- 35617, SVL ¼ 12.4 mm) from Sierra Madre del Sur, 1.2 mi on the road between Candelaria and Portillo del Rayo, Pluma Hidalgo, Oaxaca, Mexico, 1051 m. A color version of this figure is available online.

FIG. 30.—Adult Craugastor omiltemanus (A, MZFC-HE-35699 [field ID: TJD 780], SVL ¼ unavailable, photo by Thomas Devitt) from near Mazatlán, Guerrero; female (B, UTA A-66140, SVL ¼ 30.5 mm) from habitat along the road between Chichihualco and Chilpancingo, Guerrero, 2221 m; male (C, UTA A-64264, SVL ¼ 12.9 mm) from near Ayutla, Oaxaca, 1900 m; female (D, UTA A-60796, SVL ¼ 27.5 mm) from Sierra de Malinaltepec (Carretera San Luis Acatlán–Tlapa de Comonfort), 2298 m; habitat found 13.2 km west of Mazatlán, Sierra Madre del Sur (E, photo by Thomas Devitt); habitat found in the Sierra Madre del Sur west of Chilpancingo, Guerrero (F). A color version of this figure is available online.

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.

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.