CERATOPHRYIDAE

Candioti, M. Florencia Vera, 2007, Anatomy of anuran tadpoles from lentic water bodies: systematic relevance and correlation with feeding habits, Zootaxa 1600, pp. 1-175 : 26-43

CERATOPHRYIDAE

Ceratophrys cranwelli . A description of the chondrocranium of this species was provided by Lavilla and Fabrezi (1992), Fabrezi and García (1994), and Wild (1997b). Palavecino (1999) studied part of the musculature. Ulloa Kreisel (2003) described the buccopharyngeal cavity. In Vera Candioti (2005), the skeleton, musculature, oral apparatus, buccal cavity, and feeding of a new set of tadpoles were analyzed. Regarding this latter paper, the disposition of the m. tympanopharyngeus is corrected.

Chondrocranium and hyobranchial skeleton (N = 5, stage 33. Fig. 11). The chondrocranium of these larvae represents 32% of the body length, and it shows a robust construction. The maximum width is at the plane of posterior part of the subocular bar. The suprarostral cartilage is a single, posteriorly curved structure with a median constriction. The region of articulation with the trabecular horns is represented by two dorsal depressions. In the middle, ventral part, there is a stout spike ventrally oriented. The trabecular horns are quadrangular, scarcely divergent, and very short (11% of the total length of the chondrocranium). In the ethmoid region, the nasal septum, the tectum nasi, and the lamina orbitonasalis are differentiated. The cranial floor is completely cartilaginous, and on its posterior margin, the notochordal canal extends 15% of the chondrocranium length. The lateral walls of the chondrocranium are formed by the orbital cartilages. The chondrocranium is dorsally closed. The otic capsules are quadrangular, occupy nearly 25% of the chondrocranium total length, and are fused to the posterior part of the cranial roof. The fenestra ovalis (27% of the capsule length) is located ventrolaterally on each otic capsule. The palatoquadrate has a short and wide articular process, and a low, robust muscular process. The subocular bar has a smooth margin, and it is posterolaterally rounded and slightly wider. The palatoquadrate attaches to the braincase via three points: the quadratocranial commissure, the ascending process, and the larval otic process. The quadratocranial commissure is very wide and bears a well-developed quadratoethmoid process. The ascending process attaches to the braincase below the oculomotor foramen (low attachment). The lower jaw includes the Meckel’s and infrarostral cartilages, joined by a cartilaginous intermandibular commissure. Meckel’s cartilages are short, polyhedral, robust, and articulate with the articular process via the retroarticular process. The infrarostral cartilages are fused, constituting a wedge-like structure. In the hyobranchial skeleton, the ceratohyals are robust and bear low and massive anterior, lateral, and posterior processes; the anterolateral process is slightly outlined, and the articular condyle is rounded and robust. The ceratohyals are joined medially by a rectangular pars reuniens. The basihyal is absent, and the basibranchial, fused to the pars reuniens, is posteriorly wider and bears a short, rounded urobranchial process. The hypobranchial plates are subquadrangular and articulate medially, remaining a posterior, ovoid gap. The ceratobranchials, distally joined by terminal commissures, are bar-like, devoid of lateral projections and spicules.

Musculature (N = 5, stage 33. Table 4 and Fig. 12). Twenty-nine muscles appear in this species.

Oral apparatus and buccopharyngeal cavity (N = 2, stage 33. Figs. 13 and 14). The oral disc (21% of the body length) is circular with small indentations in the commissures. It has well-developed protruding lips with conical marginal papillae sparsely dispersed. Gape width occupies 20% of the body length. The suprarostrodont is very thin, V-shaped, well-keratinized, with short, pointed serrations. The infrarostrodont is well-developed and wider than the suprarostrodont; serrations are similar, short and acute. The keratodonts are arranged in eight upper and eight lower rows. The eight rows next to the rostrodonts are discontinuous, with gaps that increase their length towards the rostrodonts. The length of the rows thus decreases towards the rostrodonts, with the exception of the two lowest rows, which are respectively ¾ and ½ shorter than the immediately anterior. The keratodonts have a short, cylindrical sheath, slightly wider than the head, which is conical, spikelike. The buccal roof is triangular and scarcely pigmented. The prenarial arena lacks any structure. The choanae are elongate and obliquely arranged at an angle of 38º from the transversal line; there are no prenarial papillae on the anterior margin, and the narial valve is well-developed. Posteriorly, there is a pair of tall, laminar and trifurcate postnarial papillae. The median ridge is tall, thin and with an irregular margin. Lateral ridge papillae are absent. The buccal roof arena is not defined, due the lack of papillae; it has only a few pustules. Conspicuous groups of peritrich ciliates of the genus Vorticella are fixed on the papillae, the choanae and the prenarial and postnarial arena. Finally, dorsal velum is highly reduced or absent. In the buccal floor, there are three pairs of tall, flat and multifid infralabial papillae, transversally aligned. The tongue anlage has one pair of conical lingual papillae. The buccal floor arena is poorly defined, with scarce short, conical papillae restricted to the lateral and posterior region. Several pustules are scattered among buccal floor papillae and on the central area of the ventral velum. The buccal pockets are shallow, not perforated, and transversally arranged. The ventral velum is short, without spicular support; its margin is smooth, without marginal projections, and on the middle region, the median notch is broad and shallow. Small secretory pits appear on the posterior margin of the velum.

Gut content (N = 7, stages 35–37. Tables 21 and 22). The most frequent food-category were colonial algae (Volvocales, 45.56%) followed by crustaceans and insects. The sizes distribute between 1–50% of the tadpole body length, with modes around 4% and 20%. Furthermore, some Ceratophrys cranwelli tadpoles were kept alive and fed on Pleurodema borelli tadpoles. Ceratophrys cranwelli has a sit-and-wait feeding mode and tadpoles are consumed whole, those of smaller sizes (up to 60% of the predator size), or captured and torn apart before ingest.

Lepidobatrachus llanensis . The cartilaginous skeleton of these larvae was described by Lavilla and Fabrezi (1992) and Wild (1997b). Part of the musculature was analyzed by Palavecino (1999). Ulloa Kreisel (2003) described the buccopharyngeal cavity.

Chondrocranium and hyobranchial skeleton (N = 5, stage 33. Fig. 15). The chondrocranium of these larvae represents 35% of the body length. The maximum width is at the level of the muscular process of the palatoquadrate. The suprarostral cartilage is a single, curved structure, articulated to the trabecular horns via a thick articular region. The trabecular horns correspond to 33% of the total length of the chondrocranium and are markedly divergent. The nasal septum and the lamina orbitonasalis are formed at the analyzed stages. The cranial floor is completely cartilaginous and the carotid and craniopalatine foramina are visible. In the posterior margin of the cranial floor, the notochordal canal extends 29% of the chondrocranium length. The lateral walls of the chondrocranium are formed by the orbital cartilages. The chondrocranium is open dorsally through the frontoparietal fenestra bordered by the taeniae tecti marginales. The taenia tecti medialis is outlined. The otic capsules are quadrangular and small, occupy nearly 21% of the chondrocranium total length, and bear a small anterolateral process. The otic capsules are dorsally joined by the tectum synoticum. The palatoquadrates diverge anteriorly. The articular process is thin and short, and the muscular process is low and thick, with two angular projections in its external margin. The subocular bar is short, thin and with uniform width. The palatoquadrate attaches to the braincase via two points: the quadratocranial commissure –curved, longer than the subocular bar, devoid of processes–, and the ascending process, thin and fused to the neurocranium above the oculomotor foramen. The lower jaw includes the Meckel’s and infrarostral cartilages, joined by a cartilaginous intermandibular commissure. Meckel’s cartilages are bar-like, slightly distally wider, and lack processes. The infrarostral cartilages are fused constituting a curve structure with rounded edges. In its medial region, there is a triangular projection posteriorly oriented. In the hyobranchial skeleton, the ceratohyals are long and have conspicuous, quadrangular anterior and posterior processes; the anterolateral process is a small protuberance near the distal edge, and the lateral process is very wide and flat: the articular condyle is a robust protuberance visible from a dorsal view. The ceratohyals are medially joined by a V-shaped pars reuniens, with thin branches fused to the anterior processes. The basihyal is absent and the basibranchial is wide and short, with the caudal edge showing a short and wide urobranchial process. The hypobranchial plates are medially fused, forming a flat structure with concave posterior margin. The ceratobranchials are bar-like, devoid of lateral projections and spicules, and are distally joined by terminal commissures.

Musculature (N = 5, stage 33. Table 5 and Fig. 16). Twenty-nine muscles appear in this species.

Oral apparatus and buccopharyngeal cavity (N = 2, stages 33 and 34. Figs. 17 and 18). The mouth is slitshaped, with a gape width that reaches almost 65% of the body length. The upper lip has two small lateral flaps pending on the suprarostrodont. Small, regularly spaced papillae appear in a continuous margin surrounding the oral apparatus. The rostrodonts are very long and thin, represented by individual serrations without a common sheath; serrations are conical, acute, and larger in the infrarostrodont than in the suprarostrodont. The buccal roof shows numerous small pustules scattered on the entire roof surface. The choanae are small, almost circular, and lack prenarial papillae and narial valve. All other structures, e.g., median ridge, postnarial papillae, lateral ridge papillae, buccal roof papillae, are absent. The dorsal velum is absent. The buccal floor shows one pair of conspicuous, short, irregular infralabial papillae and numerous pustules scattered in front and behind them. The tongue anlage is scarcely visible and shows two small pustules on the medial region. The buccal pockets are unperforated and slightly obliquely oriented. The buccal floor is nearly naked, with small pustules on the lateral region and the ventral velum. The buccal floor arena is not defined, due the lack of papillae. The ventral velum is very short, with an undulate margin, and lacks spicular support, median notch, marginal projections, and a glandular epithelium.

Gut content (N = 4, stages 31–36. Tables 21 and 22). The gut content of the specimens analyzed was composed of tadpoles and large crustaceans with sizes representing 90–150% of the tadpole size.

Telmatobius cf. atacamensis . Lavilla (1983b) described the oral apparatus of this species. The remaining data here presented are unpublished.

Chondrocranium and hyobranchial skeleton (N = 2, stages 34 and 36. Fig. 19). The chondrocranium of these larvae represents 42% of the body length. The maximum width is at the plane of the posterior part of the subocular bar. The suprarostral cartilage is tetrapartite, formed of a distinguishable corpus and dorsally articulated alae. Two rectangular cartilages ventrally wider form the corpus. The alae have a well-developed processus dorsalis posterior. Near the dorsal edge of each ala, there is a pair of small, polyhedral adrostral cartilages. The trabecular horns correspond to 24% of the total length of the chondrocranium; they have relatively straight anterior margins, and on the lateroventral margin, the processus lateralis trabeculae is well-developed. The cranial floor is completely cartilaginous and in its posterior margin, the notochordal canal extends 18% of the chondrocranium length. The carotid and craniopalatine foramina are visible. The lateral walls of the chondrocranium are formed by the orbital cartilages. The chondrocranium is open dorsally through the frontoparietal fenestra lined by the taeniae tecti marginales. The nasal septum and the antorbital processes are welldeveloped, the latter approaching the dorsal tip of the muscular process. The otic capsules are ovoid, and occupy nearly 28% of the chondrocranium total length. They bear developed anterolateral process, and are dorsally joined by the tectum synoticum. The fenestra ovalis reaches 41% of the capsule length, and it is located ventrolaterally on each otic capsule. The palatoquadrate has a wide articular process, a short, subtriangular muscular process and a subocular bar posteriorly wider and rounded. The palatoquadrate attaches to the braincase via two points, the quadratocranial commissure and the ascending process. The quadratocranial commissure bears a wide, well-developed quadratoethmoid process and a long and thin pseudopterygoid process. The ascending process attaches to the braincase below the oculomotor foramen. In the lower jaw, Meckel’s cartilages are stout and elongate, with conspicuous ventromedial and retroarticular processes. The infrarostral cartilages are short and oblong. In the hyobranchial apparatus, the ceratohyals are long and have a wide, triangular anterior process, a thin, medially directed anterolateral process, an acute lateral process, and a broad posterior process; the articular condyle is a rounded protuberance visible dorsally. The ceratohyals are joined medially by the pars reuniens. The basihyal is absent and the basibranchial is longer than the pars reuniens, distally wider, and with a short, rounded urobranchial process (25% of the basibranchial length). The hypobranchial plates are triangular and flat, and they articulate medially leaving a posterior ovoid gap. The ceratobranchials are long, thin and have numerous lateral projections. They are distally joined by terminal commissures. Four well-developed cartilaginous spicules arise dorsally from each ceratobranchial.

Musculature (N = 2, stages 34 and 36. Table 6 and Figs. 20 and 21). Thirty-one muscles appear in this species.

Oral apparatus and buccopharyngeal cavity (N = 1, stage 34. Fig. 22). The oral disc represents nearly 24% of the body length and lacks lateral constrictions. Gape width reaches 17% of the body length. The papillar margin is simple, interrupted in a dorsal gap, and it is accompanied by large submarginal papillae in the commissures and lower lip. The rostrodonts are well-developed and keratinized. The keratodonts are arranged in five rows, two upper (anterior) and three lower (posterior), resulting in a LTRF 2(2)/3(1). In the buccal roof, the prenarial arena is naked. The choanae are large and obliquely arranged at an angle of 41º from the transversal line. Prenarial papillae are absent, and the narial valve is developed. The postnarial arena shows three pairs of tall, conical papillae; the medial pair is the largest. Several pustules distribute among these papillae. The lateral ridge papillae are well-developed, with three or four pustulate points. The median ridge is triangular, high, with an irregular free margin. The buccal roof arena is delimited on both sides by 7–8 tall, conical papillae, accompanied by several pustules and short papillae. Posterolaterally to the lateral ridge papillae, there appear 2-3 short, conical or bifid papillae. The glandular zone is well-developed and shows large secretory pits. The dorsal velum is large and smooth, and it is broadly interrupted medially. In the buccal floor, posteriorly to the infrarostrodonts, there is a pair of small, scarcely prominent, keratinized, bicuspidate spurs. Posteriorly, there are two pairs of infralabial papillae: the medial ones are short and conical, and the lateral ones are well-developed, tall, flat and multifid. The tongue anlage is small, and bears one pair of simple, conical lingual papillae. The buccal floor arena shows numerous papillae symmetrically arranged on the lateral and central regions. The marginal papillae are the tallest, conical and thin, in a number of 20–25 on each side; the papillae placed medially to the buccal pockets are flat, wide and bifid. In the prepocket region, there are 6– 7 small papillae. The buccal pockets are elongate and transversally oriented. The ventral velum is long and supported by spicules, and it has three pronounced, medially directed marginal projections on the filter plates and a deep median notch surrounded by rounded projections; large secretory pits appear on the posterior margin of the velum.

Gut content (N = 4, stages 25–36. Tables 21 and 22). The gut content was mainly composed of insects with sizes that represent up to 20% of tadpole size.