The Tadpole of The Mexican Tree frog Charadrahyla taeniopus ( anura : hylidae )

The tadpole of Charadrahyla taeniopus is described. This tadpole is a typical streamdweller with a long depressed body, oral disc completely surrounded by marginal papillae with numerous small submarginal papillae lateral to the mouth, and several rows of teeth on the posterior labium (6–7).


inTroducTion
The Mexican genus Charadrahyla comprises six species of large, stream-dwelling frogs that inhabit the highlands of the Sierra Madre Oriental, Sierra Madre Occidental, and the sierras of Oaxaca and Chiapas (Duellman, 2001;Campbell et al. 2009).One of these species, Charadrahyla taeniopus Gunther 1901 inhabits cloud forest between 1200 and 2100 m along the Sierra Madre Oriental in the Mexican states of Hidalgo, Puebla, and Veracruz (Duellman, 1965(Duellman, , 2001)).
The identity of the tadpole of Charadrahyla taeniopus is still uncertain.Duellman (1965) assigned a tadpole from Puebla (KU 68498) with labial tooth row formula (hereafter LTRF) 2(2)/3 and one row of large submarginal papillae to C. taeniopus, but no conclusive evidence (i.e., molecular or developmental) supports this hypothesis.
We collected tadpoles from various locations along the Sierra Madre Oriental in Mexico and determined they are Charadrahyla taeniopus.Herein, we describe the tadpole of C. taeniopus.

MaTerialS and MeThodS
We obtained previously undescribed tadpoles from various locations in the Mexican states of Hidalgo, Puebla, and Veracruz between March and June 2004 (see Comparative Materials).Most tadpoles were reared through metamorphosis to either juvenile and adult stages, except for few that were preserved in formalin (10%) at various developmental stages.All the transformed individuals were unambiguously identified as Charadrahyla taeniopus using the diagnoses of this species provided by Duellman (1965Duellman ( , 2001: 445): 445).

reSulTS
A tadpole in Stage 31 (UMMZ 239907) (Fig. 1) (measurement in mm): body length 16.2; maximum body width 8.9; tail length 27.3; total length 43.5; oral disc diameter (transverse) 5.4; eye diameter 1.9; interorbital distance 5.2; internostril distance 4.8; width of caudal musculature 4.9; maximum tail height 9.5; body slightly depressed; snout rounded in dorsal view and profile; eyes small (diameter of eye 11.7 % of body length), dorsal, not protuberant; nostril opening ovoid, not prominent, anterolaterally directed, located slightly closer to eye than to tip of snout; spiracle sinistral, angled 45 degrees with respect to horizontal plane of body; opening of spiracle located at midline of body, slightly closer to end of body than to tip of snout; inner wall of spiracle free from body (Altig and McDiarmid, 1999;Fig. 3.5 C); vent tube dextral with right wall displaced anteriorly (Altig and McDiarmid, 1999;Fig 3.5 F); tail highest at anterior third of tail, gradually tapering posteriorly, ending in a narrow round tip; dorsal fin not extending onto body; dorsal fin slightly higher than ventral fin; posterior tip of tail musculature curved dorsally.
Oral disc ventral (Fig. 1), small (diameter of oral disc 60% of body width), elliptical, not emarginate, completely surrounded by marginal papillae; marginal papillae biserial anteriorly, uniserial laterally, biserial to triserial posteriorly; one nearly complete row of medium submarginal papillae anterior to A-1; clumps of 9−12 small submarginal papillae lateral to posterior rows of teeth; LTRF 2(2)/6; gap in A-2 narrow; relative lengths of tooth rows A-1>A-2>P-1-P-5>P-6; P-6 intermittent; relative length of labial teeth rows A-1, A-2, P-1, P-2, P-3>P-4>P-5>P-6; spaces between teeth rows of posterior labium gradually diminishes from anterior to posterior; oral surface of upper jaw sheath long, wide, flat to slightly convex with wide, long, well-pigmented, lateral projections; upper and lower jaw sheaths well-keratinized, gradually more pigmented toward their serrated edges; two darkly-pigmented narrow processes extend posterodorsally from the lateral edges of the upper jaw sheath; serrated edges of upper and lower jaw sheaths slightly convex and U-shaped, respectively; upper and lower jaw sheaths bearing small, roundtipped, well-defined, discrete serrations.In preservative, body light brown, tail musculature cream; small, poorly defined spots on anterior part of dorsal fin.In life, a tadpole (UMMZ 239971-3) has body reddish brown with golden flecks, tail musculature reddish cream, and fins grayish.
Tadpoles in developmental stages later than 31 can have large blotches on tail musculature and a pigmented vent.Tadpoles in various developmental stages can have the musculature of the posterior part of the tail straight, body gray in preservative, upper jaw sheath poorly or not pigmented (UMMZ 239906-8, 239966, 239968-9, 239971-5) and poorly keratinized (i.e., with the medial part of the serrated edge slightly to sharply concave) (UMMZ 239906-8, 239972), upper jaw sheath short, serrations of upper and/or lower jaw sheaths barely distinct to absent (UMMZ 239908), P-6 continuous, row of submarginal papillae between A-1 and marginal papillae absent (UMMZ 239907), and P-1 split in two short segments and positioned on both sides of lower jaw sheath (UMMZ 239974).Tadpoles in developmental stages 26−41 can have LTRF 2(2)/5 (UMMZ 239907-8) or 2 [1](2)/6 (UMMZ 239973).Tadpoles in stage 25 can have LTRF 2(2)/4-6.Some tadpoles (UMMZ 239968, 239974-5) have LTRF 2(2)/7.One tadpole has two rows of submarginal papillae anterior to A-1 (UMMZ 239979).diScuSSion Duellman (1965) assigned the tadpole KU 68498 with LTRF 2(2)/3 and one row of submarginal papillae to Charadrahyla taeniopus.This is incorrect.This study shows that the tadpole of C. taeniopus has LTRF 2(2)/6−7 and it is a typical stream-dweller with body depressed, eyes dorsal, oral disc completely surrounded by marginal papillae, large number of teeth rows on posterior labium, and short teeth (Altig & McDiarmid, 1999).We think that the tadpole KU 68498 is Plectrohyla arborescandens, a species also found in Tezuitlan Puebla, because it has LTRF 2(2)/3, complete marginal papillae, uniserial marginal papillae surrounding the oral disc, submarginal papillae forming one row around the mouth, and P-3 shorter that P-1 and P-2, and lacks clumps of papillae laterally to the mouth (Kaplan & Heimes, 2011).Duellman (2001:921) assigned a tadpole with LTRF 2(2)/6 to Plectrohyla arborescandens Taylor 1939 but Kaplan & Heimes (2011) identified the correct tadpole of this species as one having LTRF 2(2)/3.We think that Duellman's tadpole is Charadrahyla taeniopus because it has the same labial tooth row formulae and clumps of lateral submarginal papillae as the tadpoles described in this study and also because it was collected near Tezuitlan Puebla, a locality where C. taeniopus is abundant.Altig (1987) assigned a tadpole from Hidalgo (no museum number provided) with LTRF 2(2)/7 to Plectrohyla charadricola Duellman.We think this tadpole is Charadrahyla taeniopus because it has the same labial tooth row formula as the tadpoles from Hidalgo described in this study and because C. taeniopus is very common in Hidalgo.
The tadpole of Charadrahyla taeniopus resembles those of C. altipotens Duellman 1968 andC. nephila Mendelson &Campbell 1999 by having clumps of many small submarginal papillae lateral to the rows of teeth and by lacking rows of large, discrete submarginal papillae between teeth rows and marginal papillae (Duellman, 2001); C. taeniopus differs from these species by having 6−7 posterior teeth rows.The tadpole of C. taeniopus differs from that of C. trux Adler & Dennis 1972 by having two rows of teeth on the anterior labium (Duellman, 2001).The tadpoles of C. chaneque Duellman 1961 andC. tecuani Campbell et al. 2009 are still unknown.