Miniaturization in Direct-Developing Frogs from Mexico with the Description of Six New Species Author Jameson, Tom J. M. Author Streicher, Jeffrey W. Author Manuelli, Luigi Author Head, Jason J. Author Smith, Eric N. text Herpetological Monographs 2022 2022-04-04 36 1 1 48 http://dx.doi.org/10.1655/0733-1347-36.1.1 journal article 10.1655/0733-1347-36.1.1 6518587 Craugastor polaclavus sp. nov. Holotype . — UTA A-62392 (field ID: JAC 21230; Fig. 31 ), female collected by E.N. Smith and colleagues in Portillo del Rayo , Distrito San Pedro Pochutla , Sierra Madre del Sur , Oaxaca , Mexico , 15.973038N , 96.997118W , 1550–1585 m , 24 September 2001 . Paratypes (4). — UTA A- 55246, a recent hatchling collected by E . N . Smith and José Luís Camarillo Rangel from Río Salado, Sierra Madre del Sur, Oaxaca , Mexico , 16.1941678N , 97.09758W , 1245 m , 26 September 1997 . UTA A- 66098 and MZFC-HE-35582–83, adult or subadult specimens all collected with the holotype . Referred specimen (1). — UTA A- 66097, female, same data as holotype . Diagnosis. —A species of Craugastor distinguished by the following combination of characters: (1) small adult size (maximum SVL ¼ 14.7 mm ); (2) highly reduced ossification of skeleton in adults relative to other members of series; (3) presence of posterolateral projection of the 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 no distinctive canthal stripe, 1–2 particularly dark bars below eye; (8) one or two postrictal tubercles; (9) gular region with pale spotting; (10) dorsal surface blotched; suprascapular chevron, interorbital bar; (11) pale or as background middorsal ridge; (12) dorsum smooth with only large scattered tubercles; (13) body flank darker anteriorly, no sharp delineation of color change, smooth to shagreened; (14) inguinal glands present and axillary glands absent in adults; (15) when leg adpressed to body, heel reaches nostril; (16) outer tarsal ridge with 0–4 extremely small, flat, and round tubercles, no raised fringe; (17) finger and toe pads round, finger tips not expanded, toe tips slightly expanded; (18) inner metatarsal tubercle larger than outer metatarsal tubercle. FIG. 31.—Subadult female holotype of Craugastor polaclavus (UTA A-62392, SVL ¼ 14.7 mm) from San Pedro Pochutla district, Portillo del Rayo, Oaxaca, Mexico, 1550–1585 m. Acolor version of this figure is available online. Downloaded From: https://bioone.org/journals/Herpetological-Monographs on 04 May 2022 Comparisons. — Craugastor polaclavus can be differentiated from C. candelariensis , C. mexicanus , C. montanus , C. omiltemanus , and C. saltator by the presence of vomerine odontophores (absent in C. polaclavus ). It can be differentiated from C. bitonium , and C. cueyatl by the condition of adpressed leg where the heel does not reach the nostril (reaches nostril in C. polaclavus ). It can be differentiated from C. hobartsmithi and C. pygmaeus by the absence of a posterolateral projection of the frontoparietal (present in C. polaclavus ). It can be differentiated from C. portilloensis by metatarsal tubercles of equal size (unequal in C. polaclavus ). It can be differentiated from C. rubinus by relative finger lengths of IV ¼ II (IV> II in C. polaclavus ). Description of holotype . — Holotype small female (SVL ¼ 14.7 mm ); snout rounded and short ( 0.8 mm naris–snout; 5% SVL); short eye–nostril distance ( 1.4 mm ; 7% SVL); tympanum 1.4 mm (10% SVL); mild supratympanic fold terminating in small shoulder tubercle; finger length formula III <IV ¼ II <I; single palmar tubercle; single prepollical tubercle; subarticular tubercles present on all fingers; supernumerary tubercles not present on hand; toe length formula IV <III <V <II <I; inner metatarsal tubercle larger than outer metatarsal tubercle; subarticular tubercles present on all toes; supernumerary tubercles present on plantar surface; small supracloacal fold; dark supratympanic fold in life with orange shoulder tubercle ( Fig. 25 ), shoulder tubercle color not visible in preservative; many bands present on arms and legs; left leg removed for genetic analysis. FIG. 32.—Female holotype of Craugastor portilloensis (UTA A-62393, SVL ¼ 11.4 mm) from Portillo del Rayo, Oaxaca, Mexico, 1550 m. The specimen’s leg was removed for genetic analysis. Acolor version of this figure is available online. Variations in paratypes . —Body sizes in SVL 8.2 mm (UTA A-55246), 12.3 mm (UTA A-66098), 11.6 mm (MZFC-HE-35582), 13.5 mm (MZFC-HE-35583); eye–nostril distance 11–13% SVL; tympanic ratios 7–8%. Distribution. —Intermediate elevations in the foothills of the Sierra Madre del Sur in Oaxaca 1245–1585 m ( Fig. 7 ). These habitats consist of mixed tropical dry and temperate sierra forests. Etymology. —The specific epithet is a combination of the Latin pola meaning small and clavus meaning wart. The name is an allusion to the small size and rugose appearance of several individuals in the type series. Phylogenetics. — Craugastor polaclavus was inferred to be the sister taxon of C. candelariensis with strong support in the concatenated analysis (90 ML; 0.99 BAYES; Fig. 3 ) and nDNA-only analysis (ML> 90, BAYES> 0.90; Fig. 5 ). The placement of C. polaclavus was less certain in the mtDNA, where it was found to be the sister taxon of a clade containing C . cf. hobartsmithi þ C. rubinus (ML ¼ 51, BAYES ¼ 0.74; Fig. 4 ). In terms of genetic distances ( Table 4 ), C. polaclavus was most similar to C. portilloensis (5.8%), followed by similarity to C. bitonium (5.9%). Remarks. —The skull of C. polaclavus is similar to C. mexicanus , C. omiltemanus , and C. saltator , with more anteriorly placed anterior suture of the frontoparietal and prootic than in other species. Specimens were dissected; three (UTA A-62392, 66098, and MZFC-HE-35582) seem to be subadult females with unpigmented ovaries and thin undeveloped oviducts, UTA A-66097 is an adult female with a thickened oviduct and also unpigmented ovaries containing yolked eggs, UTA A-66098 adult and MZFC-HE-35582 subadult are males with pigmented testes (smaller on second specimen), and the hatchling ( 8.2 mm SVL) was not dissected. This species likely co-occurs with C. candelariensis , C. portilloensis , and C. pygmaeus in southcentral Oaxaca ( Figs. 6 and 8 ). It was collected in sympatry with C. portilloensis at Portillo del Rayo, Oaxaca, Mexico ( Fig. 8 ). The hatchling paratype specimen (UTA A-55246) had no evidence of skeletal ossification ( Fig. 11 ).