Craugastor hobartsmithi ( Taylor 1936 )

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 : 25-27

Craugastor hobartsmithi ( Taylor 1936)

Eleutherodactylus hobartsmithi Taylor 1936:355 . Holotype male ( FMNH 100114 ) from ‘‘Uruapan, Michoacán, Mexico.’’ [Examined] .

Microbatrachylus hobartsmithi (Taylor) : Taylor 1940:501.

Craugastor hobartsmithi (Taylor) : Crawford and Smith 2005:536.

Microbatrachylus pygmaeus Duellman 1961:34 . [Misidentification].

Craugastor pygmaeus Ahumada-Carrillo et al. 2013:1338 . [Misidentification].

Diagnosis. —Based on six specimens. Aspecies of Craugastor distinguished by the following combination of characters: (1) small adult sizes (males 11.3–15.2 mm, females ~ 16.7 mm; Table 5 ); (2) full ossification of most skeletal elements in adults, lacking ossification beyond Stage 4 ( Table 3 ); (3) absence of vomerine odontophores; (4) absence of posterolateral projection of frontoparietal; (5) presence of a row of 4–6 rounded tubercles along outer edge, and 1–3 in mid upper eyelid; (6) supratympanic fold poorly developed; (7) face flank barred with or without distinctive canthal stripe; (8) one or two postrictal tubercles; (9) gular region peppered with melanocytes; (10) dorsal surfaces finely blotched, usually with dark interorbital bar and suprascapular ^-shape, some individuals with pale dorsal color and four stripes, paravertebral and lateral, originating at corners of eyes and ending above groin (lateral more prominent); (11) middorsal ridge (dark or background color); (12) mostly smooth dorsum or with just fine tubercles or folds toward back; (11) body flank darker anteriorly, around axilla, slightly tubercular; (14) inguinal glands present and axillary glands absent in adults; (15) when leg adpressed to body, heel reaches between anterior corner of eye and snout; (16) outer tarsal ridge with 4–6 rounded to slightly pointed tubercles, no raised fringe; (17) finger and toe tips round, finger tips slightly expanded, toe tips expanded; (18) similar sizes of inner and outer metatarsal tubercles.

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Comparisons. — Craugastor hobartsmithi can be differentiated from C. bitonium , C. mexicanus , C. montanus , C. omiltemanus , C. polaclavus , C. pygmaeus , and C. rubinus by an inner metatarsal tubercle that is twice the size of the outer (these are similar sizes in C. hobartsmithi ). It can be differentiated from C. candelariensis and C. saltator by the presence of vomerine odontophores (absent in C. hobartsmithi ). It can be differentiated from C. cueyatl and C. portilloensis by the presence of posterolateral projections of the frontoparietal (absent in C. hobartsmithi ).

Description. —In previous literature, C. hobartsmithi has been described as small-bodied with pigmented gonads ( Taylor 1936, 1940); presence of tubercles on the tarsus ( Duellman 1961); two palmar tubercles ( Lynch 1965); tarsus bearing a row of tubercles along its outer edge ( Lynch 1970).

Holotype (FMNH 100114) small male (13.5 mm); snout rounded and short (0.9 mm naris–snout; 6% SVL); short eye–nostril distance (1.18 mm; 8.7% SVL); tympanum 1.9 mm (14% SVL). We further examined two specimens of C. cf. hobartsmithi from coastal Michoacán (UTA A-66133–34; Fig. 25B and C ) and noted the following characteristics: supratympanic fold terminating in two postrictal tubercles; finger length formula III <IV ¼ II <I; toe length formula IV <III <V <II <I; inner metatarsal tubercle and outer metatarsaltubercle equal size.

Distribution. — Craugastor hobartsmithi occurs in the pine–oak forest of Michoacán. Craugastor cf. hobartsmithi occurs throughout western Mexico in low to intermediate habitats of Jalisco, Nayarit, Michoacán, Guerrero, and Sinaloa ( Fig. 8 ; Hardy and McDiarmid 1969). FloresCobarrubias et al. (2012) reported C. hobartsmithi from Hostotipaquillo, Jalisco. García and Ceballos (1994) reported C. hobartsmithi from coastal Jalisco. The records of C. pygmaeus reported in Duellman (1961) and AhumadaCarrillo et al. (2013) are all likely C. hobartsmithi or C. cf. hobartsmithi because our molecular results indicate that C. pygmaeus does not occur west of Guerrero. Similarly, many iNaturalist (https://www.inautralist.org, accessed June 2019) accounts of C. cf. hobartsmithi are listed under C. pygmaeus —these accounts also suggest that C. cf. hobartsmithi is much more widely distributed in western Mexico than museum collections indicate.

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Phylogenetics. — Craugastor cf. hobartsmithi was found to be the sister taxon of C. rubinus with strong support (ML ¼ 100; BAYES ¼ 1.0) in both the concatenated and separate mtDNA and nDNA analyses ( Figs. 3 , 4 , and 5). The pairwise P -distances between C. cf. hobartsmithi and C. rubinus is 3.4% ( Table 4 ); this is the smallest genetic distance between any species of the C. mexicanus series, suggesting recent divergence.

Remarks. —The skull of C. hobartsmithi is similar to C. montanus and C. pygmaeus , with more posteriorly placed anterior suture of frontoparietal and prootic than in other species. We tentatively referred several museum collections to C. hobartsmithi ( Fig. 8 ) as C. cf. hobartsmithi , but these should be further examined. The specimens of C. pygmaeus reported by Duellman (1961) from Arteaga, Michoacán, are referred to C. cf. hobartsmithi because we examined several C. pygmaeus from Oaxaca with tubercles on the outer edge of the tarsus rendering Duellman’s (1961) apomorphic character for C. hobartsmithi unreliable. Craugastor hobartsmithi may co-occur with C. pygmaeus in southcentral Guerrero ( Figs. 6 and 8 ). The tissues of C. cf. hobartsmithi used in our phylogenetic analysis originated from Colima. Although we lack a voucher specimen for the tissue, the collector of the tissue (J. Reyes-Velasco) provided us with photographs of C. cf. hobartsmithi from Montitlan, near where the tissue was collected ( Fig. 25E and F ). One female specimen of C. hobartsmithi from near Uruapan (UMMZ 94230) had several intradermal trombiculid mites on its venter ( Fig. 15D ).

Figures

FIG. 25.—View from the type locality of Craugastor hobartsmithi, Uruapan, Michoacán, looking toward Cerro Tancitaro (A). Craugastor cf. hobartsmithi; female (B, UTA A-66134, SVL ¼ 13.2 mm); male (C, MZFC-HE-35613, SVL ¼ 9.6 mm); female (D, UTA A-66133, SVL ¼ 18.3 mm); all from near Las Playitas (Carretera Playitas–Torre de Microndas), Michoacán, Mexico, 1565 m. Craugastor cf. hobartsmithi from Montitlan, Colima, Mexico photographed 13 April 2020 (E, F, not collected, photo by J. Reyes-Velasco). 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. 6.—Distribution of Craugastor mexicanus, C. montanus, C. pygmaeus, and C. saltator in Mexico and Guatemala. Dots inside symbols indicate individuals used in the molecular analyses in this study. Relevant type localities are indicated by text and arrows.

FIG. 15.—Ventral body surface in representative specimens of the Craugastor mexicanus series. Female holotype of C. bitonium (A, UTA A-64254, SVL ¼ 15.8 mm); male holotype of C. candelariensis (B, UTA A-64253, SVL ¼ 13.3 mm); male holotype of C. cueyatl (C, UTA A-62348, SVL ¼ 13.0 mm); female C. hobartsmithi (D, UMMZ 94230, SVL ~12 mm, photo by J. David Curlis); female C. mexicanus (E, UTA A-28754, SVL ¼ 35.9 mm); male C. montanus (F, UMMZ 88002, SVL ¼ 21.8 mm); female C. omiltemanus (G, UTA A-66140, SVL ¼ 30.9 mm); female holotype of C. polaclavus (H, UTA A-62392, SVL ¼ 14.7 mm); female holotype of C. portilloensis (I, UTA A-62393, SVL ¼ 11.4 mm); female C. pygmaeus (J, UTA A-54809, SVL ¼ 17.3 mm); male holotype of C. rubinus (K, UTA A-62345, SVL ¼ 12.6 mm); female C. saltator (L, UTA A-55239, SVL ¼ 38.2 mm). A color version of this figure is available online.