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Skull of adult Ceratophrys cornuta (KU 205884, 78.5-mm, left) and large adult (KU 205075, right). A: Dorsal view. B: Ventral view. C: Lateral view. col, columella; cr par, crista parotica; exoc, exoccipital; fpar, frontoparietal; jug f, jugular foramen; max, maxilla; nas, nasal; npal, neopalatine; occ con, occipital
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The adult skeleton and tadpole chondrocranium of the leptodactylid frog, Ceratophrys cornuta (Ceratophryinae), are described in detail, including the ontogenetic development of the chondrocranium and the ossification sequence of the skeleton. The chondrocranium of the carnivorous larvae is unique in lacking a frontoparietal fontanelle and possessin...
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... dorsal view, the skull of adult Ceratophrys cornuta is triangular with a broad base and a rounded apex (Fig. 1). The skull is wide and low, ca. 1.63 wider than long and ca. 0.73 lower than long. The skull is large relative to the body, which seems to be a function of the enormous jaws; the greatest width and posterior extreme of the skull are at the angles of the wide jaws. The postorbital skull roof (posterior half of the frontoparietals and ...
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... it makes a sharp angle with the steeply sloped face and sides, forming an interocular crest. The endocranium is poorly ossified and the braincase is small relative to the overall dimensions of the skull. Ossification of the prootics and sphenethmoid do not meet one another, and the sphenethmoid does not invade the region of the planum antorbitale (Fig. 1, left). These elements, however, meet to enclose the braincase as a result of ossification with age, and ossification of the sphenethmoid completely invades the region of the planum antorbitale (Fig. 1, right). The crista parotica and exoccipitals are well ossified. The skull is completely roofed. Dorsal exocranial investing bones are well ...
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... Ossification of the prootics and sphenethmoid do not meet one another, and the sphenethmoid does not invade the region of the planum antorbitale (Fig. 1, left). These elements, however, meet to enclose the braincase as a result of ossification with age, and ossification of the sphenethmoid completely invades the region of the planum antorbitale (Fig. 1, right). The crista parotica and exoccipitals are well ossified. The skull is completely roofed. Dorsal exocranial investing bones are well developed, with most of them exostosed with extensive pitted ornamentation and coossification. The large subtemporal fenestra is enclosed by the squamosal dorsally and posteriorly, the maxilla anteriorly ...
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... half of the chondrocranium is slightly narrower than the posterior half; the greatest width is slightly anterior to the level of the auditory capsules. The chondrocranium possesses robust jaw elements, a well-developed dorsal roof of cartilage covering nearly the entire braincase, and a robust hyobranchial apparatus with reduced ceratobranchia (Fig. ...
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... tadpole of Ceratophrys cornuta possesses large, well-keratinized jaw sheaths that are supported by supra-and infrarostral cartilages. In dorsal view (Fig. 10), the suprarostral is a single, solid (not fenestrated), wide, arcuate element. The central corpus of the suprarostral is flattened in the horizontal plane and has a broadly curved anterior edge and a shallow, medial, semicircular notch on the posterior edge. The alae are directed posterolaterally. The distal onethird of the alae of the ...
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... elements of the chondrocranium of Ceratophrys cornuta are considerably modified throughout development (Figs. 10-13). Most major modifications of the chondrocranium occur during Stages ...
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... 35 (Figs. 10, 11A). The chondrocranium of Ceratophrys cornuta at Stage 35 was described above. The most prominent features are the dorsal roof of cartilage that completely covers the braincase and the robust palatoquadrate cartilage with a very broad commissura quadratocranialis ...
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... 43 (Figs. 11B, 12A,B, 13A,B). Many changes have taken place since Stage 42 indicating metamorphosis has started. Nearly every element of the chondrocranium is modified, some profoundly. The two remaining pieces of the suprarostral are even more eroded and are just arches of cartilage with a slight spur of the processus posterior dorsalis remaining on ...
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... 45 (Figs. 11D, 12D, 13D). Several changes have taken place since Stage 44 and many of the modified structures reach their terminal metamorphic form. In one speci-men (KU 215769), the infrarostral is a bit more elongate laterally and arched posteriorly. In another (KU 215539), the infrarostral is even thinner lateral to its medial ends reaching essentially the ...
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... and exoccipitals. Both the exoccipitals and prootics are first observed at Stage 38. Each exoccipital arises from one center of ossification at the medial wall of the jugular foramen and lateral wall of the foramen magnum (Fig. 14A). The bones expand in all directions so that by Stage 40, each encompasses the medial half of the jugular foramen. Ossification of the exoccipitals proceeds dorsally and ventrally; posteroventrally the bones reach the base of the parasphenoid ala as early as Stage 44 (Fig. 15A), and dorsally the bones reach the frontoparietal in a ...
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... wall of the jugular foramen and lateral wall of the foramen magnum (Fig. 14A). The bones expand in all directions so that by Stage 40, each encompasses the medial half of the jugular foramen. Ossification of the exoccipitals proceeds dorsally and ventrally; posteroventrally the bones reach the base of the parasphenoid ala as early as Stage 44 (Fig. 15A), and dorsally the bones reach the frontoparietal in a 49.9-mm subadult. In a 31.4-mm juvenile, the exoccipitals completely surround the jugular foramen in bone. The exoccipitals do not completely encircle the region of the foramen magnum and meet one another medially until in the adult, and then they are united dorsally first. The ...
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... Each frontoparietal arises from two centers of ossification, which are first observed simultaneously at Stage 38 (Fig. 14A). Bone appears on the dorsal roof of cartilage along the taenia tecta marginalis and posterolaterally above the medial wall of the auditory capsule. During Stage 38, the two centers fuse and ossification spreads anteriorly, medially, and posteriorly. There is little change in the posterior end of the frontoparietal after this stage, ...
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... frontoparietals make medial contact posteriorly above the tectum synoticum. Postmetamorphically (25.9-mm juvenile), the frontoparietals reach the nasals anteriorly; posterolaterally the otic flange of each frontoparietal extends to reach the zygomatic ramus of the squamosal to form the postorbital arch of bone that encloses the orbit posteriorly (Fig. 16). Complete medial contact between the frontoparietals was first noted in a 28.8-mm juvenile, but the timing of this event varies. Some larger individuals lack complete medial contact between frontoparietals, and one individual (a 29.8-mm juvenile) lacks any medial contact between the elements. However, at 34.3-mm and larger, all ...
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... dorsal to the antorbital process, on what is to become the maxillary process. Ossification is first observed at Stage 44 (KU 215768) and rapidly progresses anteromedially along the posteromedial edge of the naris and posteriorly dorsal to the taenia tecta marginalis until it reaches the tip of the frontoparietal postmetamorphically (25.9-mm; Fig. 16). Laterally, in a 25.9-mm juvenile, the maxillary process of each nasal meets the zygomatic ramus of the squamosal beneath the orbit (Fig. 16) and, in a 26.5-mm juvenile, reaches the maxilla. The maxillary process continues to broaden with further development. Medial articulation of the nasals first occurs in a 28.8-mm juvenile. The ...
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... rapidly progresses anteromedially along the posteromedial edge of the naris and posteriorly dorsal to the taenia tecta marginalis until it reaches the tip of the frontoparietal postmetamorphically (25.9-mm; Fig. 16). Laterally, in a 25.9-mm juvenile, the maxillary process of each nasal meets the zygomatic ramus of the squamosal beneath the orbit (Fig. 16) and, in a 26.5-mm juvenile, reaches the maxilla. The maxillary process continues to broaden with further development. Medial articulation of the nasals first occurs in a 28.8-mm juvenile. The pattern of appearance of exostosis of the nasal follows the sequence of ossification; exostosis is first observed laterally on the maxillary ...
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... The parasphenoid is first observed at Stage 38 where it has welldeveloped cultriform and alary processes (Fig. 14A). There is little change in the parasphenoid other than lengthening of the cultriform process anteriorly and the alae laterally; the latter make contact with the exoccipitals posteroventrally at Stage 44 ( Fig. 15A) and reach the medial process of the pterygoid at Stage 45. The cultriform process reaches the level of the anterior edge ...
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... The parasphenoid is first observed at Stage 38 where it has welldeveloped cultriform and alary processes (Fig. 14A). There is little change in the parasphenoid other than lengthening of the cultriform process anteriorly and the alae laterally; the latter make contact with the exoccipitals posteroventrally at Stage 44 ( Fig. 15A) and reach the medial process of the pterygoid at Stage 45. The cultriform process reaches the level of the anterior edge of the orbit postmetamorphically in a 25.9-mm juvenile, but is not in contact with the neopalatines or vomers until in large adults. Posteroventrally, the parasphenoid alae are united with the exoccipitals and ...
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... The neopalatines are first observed postmetamorphically in a 25.9-mm juvenile as narrow slivers of bones overlying cartilage of the planum antorbitale (Fig. 16). Ossification proceeds medially and laterally; in a 28.8-mm juvenile, the neopalatine is in contact with the pars palatina of the maxilla laterally. In a 49.9-mm subadult, the neopalatine articulates with the vomer anteromedially, but the neopalatines do not meet each other or the cultriform process of the parasphenoid until in mature ...
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... Each vomer arises from two centers of ossification. Ossification is first observed at Stage 44 near what will be the center of the vomer (Fig. 15A). The second center of ossification is first observed at Stage 45, located on the lateral edge near the location of the prechoanal process of the presumptive bone. During Stage 45 these two centers unite when the prechoanal process is completely ossified with ossification present laterally along the posterior edge of the anterior ...
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... the prechoanal process of the presumptive bone. During Stage 45 these two centers unite when the prechoanal process is completely ossified with ossification present laterally along the posterior edge of the anterior process. Postmetamorphically, in a 25.9-mm juvenile, ossification of the anterior process reaches the pars palatina of the maxilla (Fig. 16). Vomerine ossification progresses until it reaches the neopalatine posteromedially and the premaxilla anterolaterally in a 49.9-mm subadult. Articulation between the vomer and the cultriform process of the parasphenoid is present only in larger adults. The vomers are edentate. Odontoids are present in postmetamorphic juveniles, and are ...
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... Each premaxilla arises from a single center of ossification located in the region of the pars dorsalis. Ossification is first observed at Stage 42, in which the premaxilla is represented by an inverted T-shaped element (Fig. 14B) that is ossified in the region of the pars dorsalis, and laterally and medially along the dorsal edge of the pars dentalis. Teeth first appear at Stage 43. Ossification of each premaxilla proceeds laterally, medially, and dorsally. Posteroventromedially, the palatine processes of each pars palatina develop and articulate medially at ...
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... 14B) that is ossified in the region of the pars dorsalis, and laterally and medially along the dorsal edge of the pars dentalis. Teeth first appear at Stage 43. Ossification of each premaxilla proceeds laterally, medially, and dorsally. Posteroventromedially, the palatine processes of each pars palatina develop and articulate medially at Stage 45 (Fig. 15B). Postmetamorphically, ossification lateral to the palatine processes makes the pars palatina less pronounced. Laterally, the pars dentalis of the premaxilla meets the pars dentalis of the maxilla in a 25.9-mm juvenile (Fig. 16). Ven-trally, in the same individual, the posterolaterally directed maxillary process of the premaxilla ...
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... Posteroventromedially, the palatine processes of each pars palatina develop and articulate medially at Stage 45 (Fig. 15B). Postmetamorphically, ossification lateral to the palatine processes makes the pars palatina less pronounced. Laterally, the pars dentalis of the premaxilla meets the pars dentalis of the maxilla in a 25.9-mm juvenile (Fig. 16). Ven-trally, in the same individual, the posterolaterally directed maxillary process of the premaxilla broadly invests the pars palatina of the maxillae ventrally. The distal terminus of the maxillary process of the premaxilla reaches the pars palatina of the maxilla in a 27.5-mm juvenile, and the vomer in a 49.9-mm subadult. Ventral ...
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... Ossification proceeds during Stage 43 with the pars facialis expanding dorsally and laterally, and a distinct pars dentalis expanding anteromedially and posterolaterally; teeth are apparent at this stage as well. At Stage 44 the pars dentalis is extended far posterolaterally. At Stage 45, the pars facialis begins to develop posterodorsally (Fig. 15B). Postmetamorphically, in a 25.9-mm juvenile, the pars dentalis articulates with the pars dentalis of the premaxillae and the pars palatina articulates with the vomer. Also in this specimen, the posteromedial process of the maxilla articulates with the ventral edge of the anterior process of the pterygoid and the pars facialis ...
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... juvenile, the pars dentalis articulates with the pars dentalis of the premaxillae and the pars palatina articulates with the vomer. Also in this specimen, the posteromedial process of the maxilla articulates with the ventral edge of the anterior process of the pterygoid and the pars facialis articulates with the zygomatic ramus of the squamosal (Fig. 16). The pars facialis articulates with the maxillary process of the nasal in a 26.5-mm juvenile. Posteroventrally, the pars palatina contacts the neopalatine in a 28.8-mm juvenile. Exostosis is first observed on the pars facialis in a 34.3-mm juvenile and completely covers this part of the maxillae as in the adult in a 41.0-mm ...
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... The quadratojugal arises from a single center of ossification. Ossification is first observed as a small V-shaped bone dorsal to the articular process of the palatoquadrate at Stage 44, and by Stage 45, bony articulation is made with both the maxilla and the squamosal, with the articulation of the former being much broader (Fig. 15B). Medially the quadratojugal articulates with the pterygoid; this surface of the quadratojugal is the last to develop, ossifying and enlarging gradually reaching the adult form in a 28.8-mm juvenile. There is no exostosis of the ...
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... at Stage 43 (KU 215986); there is a vertical element along the lateral side of the ventral ramus just above the lateral margin of the palatoquadrate extending from the articular process to the muscular process. Ossification of the zygomatic ramus appears as a horizontal element (KU 215768), just dorsal to the posterior end of the ventral ramus (Fig. 15A). Ossification of the otic ramus (5 otic element 5 supratemporal of Griffiths, '54a) appears more posteriorly above the lateral extreme of the auditory capsule (KU 215768). Ossification of the ventral ramus expands dorsally to reach the zygomatic ramus, and ventrally to articulate with the quadratojugal in Stage 45. Ossification of the ...
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... extreme of the auditory capsule (KU 215768). Ossification of the ventral ramus expands dorsally to reach the zygomatic ramus, and ventrally to articulate with the quadratojugal in Stage 45. Ossification of the otic ramus extends anteriorly to unite with the union of the zygomatic and ventral rami thereby forming a T-shaped element in Stage 45 (Fig. 15B). Postmetamorphically, in a 25.9-mm juvenile, the squamosal articulates with the maxillary process of the nasal, the pars facialis of the maxillae anterolaterally below the orbit, the frontoparietal (via the zygomatic ramus) posterior to the orbit thus forming the postorbital arch, the anterior process of the pterygoid ventromedially, ...
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... squamosal articulates with the maxillary process of the nasal, the pars facialis of the maxillae anterolaterally below the orbit, the frontoparietal (via the zygomatic ramus) posterior to the orbit thus forming the postorbital arch, the anterior process of the pterygoid ventromedially, and the posterior process of the pterygoid posteroventrally (Fig. 16). The otic ramus expands posteromedially and in a 49.9-mm individual, the otic ramus and the ossified crista parotica are in contact with each other reaching the adult form. There is little additional change, other than the posterior expansion of the otic ramus as a horn-shaped process and exostosis of the otic, ventral, and zygomatic ...
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... The pterygoid arises from a single center of ossification at the base of the anterior and posterior processes ventral to the posteromedial edge of the palatoquadrate cartilage. Ossification is first observed at Stage 44 and quickly spreads along the anterior process, and less so up the posterior and medial processes (Fig. 15A). The medial process articulates with the parasphenoid ala at Stage 45. In a postmetamorphic 25.9-mm juvenile, the medial and posterior processes are fully developed and the anterior process reaches the pars palatina of the maxilla, the zygomatic ramus of the squamosal (variably so though in postmetamorphic specimens), and the nasal; ...
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... 25.9-mm juvenile, the medial and posterior processes are fully developed and the anterior process reaches the pars palatina of the maxilla, the zygomatic ramus of the squamosal (variably so though in postmetamorphic specimens), and the nasal; the base of the anterior process articulates with the posteromedial process of the maxilla (Fig. 16). The posterior process invests the medial end of Stippling indicates bone. angspl, angulosplenial; den, dentary; fpar, frontoparietal; nas, nasal; pro, prootic; pter, pterygoid; qj, quadratojugal; spmax, septomaxilla; sq, squamosal; vom, vomer. the palatoquadrate. Hyperossification in large adults completely obscures the articulations ...
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... angulosplenial and dentary arise simultaneously at Stage 44, each from a single center of ossification (Fig. 15A). Both the angulosplenial and dentary appear as long slivers of bone-the angulosplenial along the medial edge of the posterior half of the mandible, and the dentary along the anterior edge of the mandible, just lateral to the mandibular symphysis. The dentary is thinner and shorter than the angulosplenial and their lengths do not ...
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... symphysis. The dentary is thinner and shorter than the angulosplenial and their lengths do not overlap. Ossification of both elements spreads both anteriorly and posteriorly, but posterior ossification of the dentary is less extensive than that of the angulosplenial. At Stage 45, both elements broadly overlap lengthwise, but there is no contact (Fig. ...
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... mentomeckelian bones first appear in a postmetamorphic, 25.9-mm juvenile, and the angulosplenial constitutes most of the posterolateral aspect of the mandible, whereas the dentary forms the anterodorsal surface (Fig. 16). The elements are in broad contact along their anterior edges. The dentary possesses a low, sharp dorsal ridge. In a 26.5-mm juvenile, the mentomeckelian bones are completely ossified and in contact with the angulosplenial posterolaterally. The mentomeckelian bones expand posteriorly, forming the precursors of the palatine processes, ...
Citations
... According to Dias et al. (2019Dias et al. ( , 2023, the cartilago suprarostralis forming a single element, with fully fused pars corporis, is a synapomorphy for Dendropsophus, although the pars corporis with a medial notch has been recorded for D. ebraccatus (D. leucophyllatus group), D. molitor (D. molitor group), and D. soaresi (D. marmoratus group) (Haas, 2003;Arenas-Rodríguez et al., 2018;present study). This configuration of the cartilago suprarostralis forming a single element is not common (Dias et al., 2019), although it arose independently in several families (Ceratophryidae, Dicroglossidae, Hylidae, and Microhylidae; Ruibal and Thomas, 1988;Wild, 1997;Candioti, 2005Candioti, , 2007Haas et al., 2014). ...
Although data from the internal oral anatomy and chondrocranium of anuran larvae can be used to resolve taxonomic questions, there is no information on these characteristics for species of the Dendropsophus marmoratus group. Herein, we provide a complete description of the tadpole of D. soaresi, presenting additional information about the external larval morphology and unpublished data on internal oral anatomy and chondrocranium of specimens collected in the state of Piauí, northeastern Brazil. The measurements and morphological characters were based on 10 tadpoles in stages 35−36. Two tadpoles in stage 36 and one in stage 35 were dissected for analysis of the internal oral anatomy. To describe the chondrocranium, six stage 36 tadpoles were cleared and double-stained. We find small differences concerning the original description of the external morphology, such as body shape, oral disk size, shape and height of the fins, and position of the vent tube. We also present additional information on coloration in life and morphometric details. Similar to other species of the genus, the tadpole of D. soaresi has a reduced number of structures in the buccopharyngeal region, although presenting lingual papillae and a rounded cornified structure in the prenarial arena. Also, D. soaresi presents a set of chondrocranial traits that are not found in other species of the genus and are possible synapomorphies for the D. marmoratus group. This variation highlights the potential of larval morphology as a source of evidence for Dendropsophus systematics. However, additional research on the internal anatomy of Dendropsophus species, especially those of the D. marmoratus group, are essential to clarify the phylogenetic relationships of the genus.
... In early limbed vertebrates (i.e., Tetrapoda sensu lato, or Stegocephali sensu Laurin, 2020; Fig. 1) the "cheek" ancestrally consisted of the jugal, postorbital, squamosal, and quadratojugal. Often, the maxilla extended posteriorly to form the ventral "cheek" margin as well (e.g., Clack, 1997;Holmes et al., 1998;Sigurdsen & Bolt, 2010;Porro et al., 2015), which can be observed similarly in anurans (e.g., Wild, 1997;Paluh et al., 2020). The ancestral skull table incorporated the parietal, postfrontal, supratemporal, postparietal, tabular, and -in some groups -the intertemporal. ...
... However, cases of secondary hyperossifications of the skull bones are known in various anurans (Paluh et al., 2020), where the latters can result in a fully closed temporal region. Nonetheless, in many taxa an infratemporal fenestra is present, and sometimes a supratemporal fenestra appears (Boas, 1915;Wild, 1997;AmphibiaTree & Gosselin-Ildari, 2008;Paluh et al., 2020). In most of these groups, the temporal openings evolved independently from amniotes. ...
The diversity and evolution of the temporal skull region is a classical text book example of comparative anatomy. In the earliest land vertebrates this region was, in most cases, completely covered by an armor of dermal bones. This armor has been successively reduced over time, leading most famously to the evolution of temporal fenestrae and marginal excavations. Such temporal openings are widespread in extant Tetrapoda, but especially their great diversity within Amniota (mammals and reptiles, including birds) inspired many early studies on the potential phylogenetic and evolutionary implications of temporal openings. In the early 20th century, this led to various researchers naming new taxa that were mainly defined by their temporal morphology, with Anapsida, Synapsida, Diapsida, and Euryapsida being the most known. Most of these taxa are not considered to represent natural groupings anymore; instead, new fossil findings and analyses confirmed that similar types of temporal openings independently evolved several times within, as well as outside of Amniota. Thus, the main focus of temporal region research has been on their functional morphology. The forces generated by the external jaw adductors hereby seem to play an essential role, but additionally the impact of neck mechanics, skull shape, developmental biology, and others are being discussed. In this short review, we summarize the research history and the current state of art to inspire a more integrative morphofunctional and evolutionary discussion of this widely-known character complex in research and education.
... Reis et al. (2020) identified that one of the main variations in the skull of the genus Brachycephalus is related to the shape of the frontoparietal and indicates that species of the B. ephippium group have a more derived and hyperossified skull. The development and degree of the ossification of bones can be related to heterochronic processes (Alberch et al. 1997;Wild 1997), although Trueb and Alberch (1985) suggests that size and the degree of ossification can be variables independent of heterochrony. In this way, the evolution and development of hyperossification and fusion of bone elements (including the frontoparietal) in the skull of species of the Brachycephalus genus is not completely elucidated and more studies related to osteology in the genus, mainly related to the ontogeny of the skeleton, are necessary. ...
The number of described species of Brachycephalus has rapidly increased in the last decade (n = 22, which represents 56% of the total). Species of the genus Brachycephalus are mostly distributed in isolated mountaintops from Bahia (northeastern Brazil) to Santa Catarina states (southern Brazil), each one occupying only one or a few adjacent mountaintops. Herein, we described a new species of Brachycephalus of the B. pernix group, from Serra do Tabuleiro in Santa Catarina state, which also represents the southernmost known species. The new species can be distinguished from its congeners by a combination of characters, including the following: (1) “bufoniform” body; (2) small adult SVL: 9.57–11.10 mm for males and 10.88–12.70 mm for females; (3) head proportionally small (HL/SVL 19–28%) and eye proportionally large (ED/HL 36–56%); (4) dorsum texture rough; (5) snout shape rounded in dorsal and lateral views; (6) general dorsal body color olive green with head, arms and legs yellow-orangish scattered with olive green, and an orangish vertebral stripe spotted with white and brown colors; (7) skull and skeleton without hyperossification; (8) frontoparietal and sphenethmoid not fused; (9) advertisement with one or two high-frequency notes (6,115–6,562 Hz), and 2–4 pulses per note. The type locality is adjacent to Parque Estadual da Serra do Tabuleiro, a protected area, but we observed various agricultural activities in this locality, including the presence of exotic plants, which can change the amount and the quality of leaf litter, somehow compromising the population of the new species. Another aggravating factor is that the municipality of São Bonifácio has conflicts over land use with irregular occupation and unfinished expropriation processes in Parque Estadual da Serra do Tabuleiro. Considering that Brachycephalus sp. nov. is probably a mountaintop microendemic species, it is paramount that future studies quantifying the new species’ full distribution and evaluating population trends to accurately assess its conservation status.
... Rage (1981) mentioned the presence of two other fragmentary skulls closely resembling those published by De Stefano (1903) in the material recovered at that time from the new excavations in the late Eocene Phosphorites du Quercy, and came to the conclusion that they correspond to ceratophryids (at the time classified within an expanded concept of Leptodactylidae), an extant South American group, fossils of which were known from the Palaeogene and Neogene of Patagonia (Schaeffer 1949, Báez and Gasparini 1977, Barcelos and dos Santos 2023. Such taxonomic allocation was seemingly supported by developmental studies which revealed that during the development of Ceratophrys Maximilian zu Wied-Neuwied, 1824, the lamella alaris of its squamosum expands far anteriorly between the nasal and maxilla (Wild 1997). Accordingly, affinities with leptodactylids (or ceratophryids, depending on the nomenclature) were assumed by subsequent workers (Roček and Lamaud 1995, Sanchiz 1998, Rage 2006, Rage and Roček 2007, Roček 2013. ...
... As mentioned above, however, one peculiar character of Thaumastosaurus is shared with the early postmetamorphic Ceratophrys, namely the elongated anterior portion of the lamella alaris of the squamosum along the dorsal margin of the maxilla, thus excluding the maxilla from the orbital margin (Lynch 1978: fig. 74D-E;Wild 1997). However, in other characters perceived as more notable at the higher taxonomic level, Thaumastosaurus does in fact differ from Ceratophrys (broad postorbital connection between the squamosum and frontoparietal, all vertebrae procoelous with V 8 not biconcave, and pectoral girdle arciferal). ...
We present new disarticulated cranial elements of the Eocene frog Thaumastosaurus from several localities in the Phosphorites du Quercy, France, providing novel information about the variation of its anatomical characteristics. With the use of micro-computed tomography (μCT) scanning technology, we examine and discuss various types of dermal cranial ornamentation in extant Pyxicephalus, the closest extant relative of Thaumastosaurus, in which these features are useful in species diagnoses, paying particular attention to the individual and ontogenetic variation, and sexual dimorphism, as well as interspecific variation among extant species. We suggest that various types of dermal cranial ornamentation in Thaumastosaurus could be potentially used in diagnoses at species level, although ontogenetic variation should be taken into consideration. Apart from ornamentation, the size and general morphology of the maxillae and squamosa in Thaumastosaurus reveal an unexpected disparity of morphotypes, which suggests the potential presence of cryptic taxa. Some squamosa reveal that their processus zygomaticus extended up to the postnasal wall, so their associated maxillae were excluded from the orbital margin, whereas others were short and their respective maxillae participated in the formation of the orbital margin. Thaumastosaurus is envisaged as the product of an Early Palaeogene direct, potentially overseas, dispersal from isolated Afro-Arabia to Europe.
... Specializations in fiber composition of the jaw-adductor muscles of Ceratophrys frogs, to assist in subduing prey, would not be surprising given that they possess several characteristics that make them formidable biters. The disproportionately large head, large jaw width-to-length ratio, and heavily ossified skull of these frogs are associated with forceful biting and the consumption of large prey (Emerson, 1985;Paluh et al., 2020;Wild, 1997). These traits are combined with an especially strong motivation to capture and consume large prey, as indicated by accounts of these frogs attempting to consume animals larger than themselves (Chávez et al., 2011), as well as roadkill (Székely et al., 2019). ...
Most frogs have weak jaws that play a relatively minor role in tongue-mediated prey capture. Horned frogs (Ceratophrys spp.), however, follow the projection of a large tongue with a vice-like grip of their jaws to hold and immobilize prey. Prey include relatively large vertebrates, which they may restrain for minutes to possibly hours. High endurance behaviors, such as prolonged biting, require that muscles be capable of sustained force production. The feeding behavior of Ceratophrys suggests that their jaw-adductor muscles may be capable of powering sustained bites for long periods. We examined the capacity for sustained bite force by conducting an in situ experiment during which we measured bite force while bilaterally and supramaximally stimulating the jaw-adductor muscles of euthanized Cranwell's horned frogs (C. cranwelli). Muscles were stimulated for at least 60 min with a series of tetanic trains, with one experiment lasting over 6 h. We found that a significant sustained force develops during the first few minutes of the experiment, and this force is present between tetanic trains when the muscles are not being stimulated. The sustained force persists long after tetanic forces are barely detectable. The observed sustained force phenomenon parallels that observed for the jaw-adductor muscles of alligator lizards (Elgaria), another animal capable of sustained biting. The ability to bite with sustained and significant force by C. cranwelli may be facilitated by a configuration of different muscle fiber types, such as slow tonic fibers, as well as specializations in the muscle fibers that mitigate the effects of fatigue.
... Pronounced dermal sculpture is characteristic of skull in Pelobates and Ceratophrys species (Pelobatidae and Ceratophryidae, respectively). And it is in the ontogeny of P. fuscus and C. cornuta that the appearance of an "additional" dermal bone, which later fuses with the frontoparietal, was observed (Sewertzow, 1891;Roček, 1981;Wild, 1997). According to W. Reinbach (1939), in P. fuscus this bone appearing on the roof of the otic capsule is homologous to the supratemporal of fossil amphibians. ...
The relative independence of ontogenetic processes, which is characteristic of amphibians, determines the possibility of shifts in the rate and timing of the ontogenetic events, or heterochronies. Heteroch-ronies give rise to ontogenetic and morphological diversity in amphibians, which can occur without significant genetic changes. Heterochrony-related neoteny, miniaturization and paedomorphic underdevelopment, as well as loss of ancestral traits due to their transition into a latent capacities state with the possibility of secondary recapitulation are phenomena typical of both recent and fossil amphibians.
... Due to the loss of the jugal and postorbital in anurans, the infratemporal fenestra in such hyperossified taxa is anteriorly bordered by the maxilla (e.g. Wild, 1997). ...
The morphology of the temporal region in the tetrapod skull traditionally has been a widely discussed feature of vertebrate anatomy. The evolution of different temporal openings in Amniota (mammals, birds, and reptiles), Lissamphibia (frogs, salamanders, and caecilians), and several extinct tetrapod groups has sparked debates on the phylogenetic, developmental, and functional background of this region in the tetrapod skull. This led most famously to the erection of different amniote taxa based on the number and position of temporal fenestrae in their skulls. However, most of these taxa are no longer recognised to represent natural groupings and the morphology of the temporal region is not necessarily an adequate trait for use in the reconstruction of amniote phylogenies. Yet, new fossil finds, most notably of parareptiles and stem-turtles, as well as modern embryological and biomechanical studies continue to provide new insights into the morphological diversity of the temporal region. Here, we introduce a novel comprehensive classification scheme for the various temporal morphotypes in all Tetrapoda that is independent of phylogeny and previous terminology and may facilitate morphological comparisons in future studies. We then review the history of research on the temporal region in the tetrapod skull. We document how, from the early 19th century with the first recognition of differences in the temporal region to the first proposals of phylogenetic relationships and their assessment over the centuries, the phylogenetic perspective on the temporal region has developed, and we highlight the controversies that still remain. We also compare the different functional and developmental drivers proposed for the observed morphological diversity and how the effects of internal and external factors on the structure of the tetrapod skull have been interpreted.
... Although osteological development of anurans has been studied since the 19th century (Parker, 1875), only a few studies have documented a relatively complete development of both the cranial and postcranial skeletons (Banbury & Maglia, 2006;Barrionuevo, 2013;Fabrezi et al., 2012;Hoyos et al., 2012;Maglia & Púgener, 1998;Púgener & Maglia, 1997;de Sá, 1988;de Sá & Trueb, 1991;Shearman & Maglia, 2015;Trueb & Hanken, 1992;Trueb et al., 2000;Vera & Ponssa, 2014;Wiens, 1989;Wild, 1997). Moreover, the quantitative data on cranial and postcranial changes over the course of larval development in anurans remain rare (Larson, 2005). ...
... Based on the literature (Banbury & Maglia, 2006;Barrionuevo, 2018;Dunlap & Sanchiz, 1996;Fabrezi et al., 2012;Gaudin, 1973;Haas, 1999;Maglia & Púgener, 1998;Púgener & Maglia, 1997;de Sá, 1988;de Sá & Trueb, 1991;Shearman & Maglia, 2015;Trueb et al., 2011;Trueb & Hanken, 1992;Wiens, 1989;Wild, 1997), the relative osteological ossification sequences of Microhyla fissipes and 18 species from Neobatrachia, Mesobatrachia and Archaeobatrachia were compared (see Table S2). To identify ossification heterochronic patterns within the phylogenetic context, a heatmap was utilized to show the relative cranial and postcranial ossification sequences of these species using SigmaPlot 12.5. ...
Describing osteological development is of great importance for understanding vertebrate phenotypic variations, form‐functional transitions and ecological adaptations. Anurans exhibit dramatic changes in their morphology, habitat preferences, diet and behaviour between the tadpole and frog stages. However, the anatomical details of their cranial and postcranial development have not been extensively studied, especially in Microhylidae. In this work, we studied the microhylid Microhyla fissipes, commonly known as the ornamented pygmy frog, a small‐sized frog with fast metamorphosis. Its osteological development was comprehensively described based on 120 cleared and stained specimens, including six tadpoles for each stage between 28 and 45, six juveniles and six adults. Additionally, 22 osteological traits of these specimens involved in food acquisition, respiration, audition and locomotion were selected and measured to reflect the changes in tadpole ecological functions during metamorphosis. Our study provides the first detailed qualitative and quantitative developmental information about these structures. Our results have confirmed that skeletal elements (viz., neopalatines, omosternum, clavicles and procoracoids) absent in adults are not detected during development. Our data reveal that morphologically, radical transformations of the cranial structures related to feeding and breathing are completed within stages 42–45 (72 h), but the relative length and width of these skeletons have changed in earlier stages. The postcranial skeletons correlated with locomotion are well developed before stage 42 and approach the adult morphology at stage 45. Indeed, the relative length of the pectoral girdle and forelimb reaches the adult level at stage 42 and stage 45, respectively, whereas that of the vertebral column, pelvic girdle and hind limbs increases from their appearance until reaching adulthood. Based on published accounts of 19 species from Neobatrachia, Mesobatrachia and Archaeobatrachia, cranial elements are among the first ossified skeletons in most studied species, whereas sphenethmoids, neopalatines, quadratojugals, mentomeckelians, carpals and tarsals tend to ossify after metamorphosis. These results will help us to better understand the ecomorphological transformations of anurans from aquatic to terrestrial life. Meanwhile, detailed morphological and quantitative accounts of the osteological development of Microhyla fissipes will provide a foundation for further study. Microhyla fissipes (Anura, Neobatrachia, Microhylidae) is known as a small‐sized and fast metamorphic frog. We provide the anatomical details of its cranial and postcranial development and quantify 22 skeletal traits mainly related to food acquisition, respiration and locomotion based on 120 cleared and stained specimens. The results will help us to better understand the ecomorphological transformations of anurans from aquatic to terrestrial life.
... Their oddlooking appearance, with large heads, wide gapes and fang-like teeth, bizarre carnivorous larvae and aggressive behaviour, coupled with the small size of the family, have made ceratophryids particularly attractive for diverse scientific studies. Ongoing research topics on this group include diverse aspects of their larval anatomy (Quinzio et al. 2006;Ziermann et al. 2013;Quinzio & Fabrezi 2019), their sound-producing mechanism (Natale et al. 2011), the development of various body parts (Fabrezi 2011;Quinzio & Fabrezi 2012Fabrezi & Cruz 2014;Amin et al. 2015;Fabrezi et al. 2016;Grosso et al. 2020), adult osteology (Wild 1997;Fabrezi 2006;Fabrezi et al. 2016;B aez & G omez 2018), myology ) and other aspects of their adult soft anatomy (Kleinteich & Gorb 2014), karyology (Vieira et al. 2006), diet (Schalk et al. 2014;Sz ekely et al. 2019), behaviour and performance (Zaidan & Leite 2012;Ortiz et al. 2013;Schalk & Fitzgerald 2015;Lappin et al. 2017), ecotoxicology (Salgado Costa et al. 2018) and phylogeny (Fabrezi 2006;Fabrezi & Quinzio 2008;Faivovich et al. 2014;B aez & G omez 2018;Brusquetti et al. 2018), among others. ...
... Ceratophrys aurita has been considered more closely allied to Ce. cornuta than to Ce. ornata by various authors (e.g. Cochran & Goin 1970;Wild 1997;Agnolin 2005), but the inverse hypothesis gained support from phylogenetic studies based on different types of data (Lynch 1982;Maxson & Ruibal 1988;Per ı 1993a;Faivovich et al. 2014). Among the latter, hypotheses based on morphology regard Ce. aurita and Ce. ...
... In agreement with the molecular phylogeny of Faivovich et al. (2014), we find sister-group relationships between Ce. cranwelli and Ce. ornata with low node support values, which in other quantitative morphological analyses have been recovered as successive sister taxa of Ce. aurita or all other species of the genus (Lynch 1982;Per ı 1993a;Wild 1997), and between Ce. cornuta and Ce. calacarata with high jackknife values. ...
South American horned frogs (Ceratophryidae), with their large heads, wide gapes and fang-like teeth, are among the most charismatic, best-known and well-studied neobatrachian anurans. The family comprises 12 extant species with hyperossified skulls and has a relatively rich fossil record, particularly in the Pampas, which dates back to the late Miocene. However, several records have been overlooked in recent summaries, and many taxonomic assignments remain indeterminate or are questionable and have yet to be tested within a quantitative phylogenetic framework. Here we provide a complete up-to-date survey of the palaeontological record of Ceratophryidae, including some remarkable new records. We also tested their systematic position through comprehensive phylogenetic analyses based on osteological data, providing several synapomorphies for all relevant nodes. Finally, we discuss these integrated data in relation to divergence time estimates, and propose a set of fossil calibrations that provide hard minimum bounds for crown-group Ceratophryidae and the subclades within it, and illuminate the acquisition of polyploidy within the group.
... The symmetry, serial patterns, and development of the vertebral column and ilio-sacral complex in anurans have been well-documented in a broad range of studies that can serve as references for the norm of the anuran body plan (e.g., Gaupp 1896, Lynch 1973, Wiens 1989, Wild 1997, Maglia & Pugener 1998, Haas 1999, Trueb et al. 2000, Sheil & Alamillo 2005, Banbury & Maglia 2006, Handri gan & Wassersug 2007, Pugener & Maglia 2009a,b, Hoyos et al. 2012, Kovalenko & Kruzhkova 2013b, Vera & Ponssa 2013, Biton et al. 2016, Soliz & Ponssa 2016, Senevirathne et al. 2020. Although Shearman & Maglia (2014) concluded that the available accounts on anuran skeletal morphology cover only a small fraction of the known number of species (Frost 2020), many of the anuran subclades are actually covered by reports of exemplar species. ...
We present accounts of vertebral anomalies in 17 individuals representing 13 species of anuran amphibians. These cases were detected while perusing a larger survey on the skeleton of frogs, for which µCT scans of a broad range of species were collected and evaluated. Our data and reports from the literature suggest that malformations, asymmetries, and irregularities, if present, appear to be particularly prevalent in the posterior region of the axial skeleton in frogs. Anomalies at the trunk-tail boundary, i.e., at the sacrum and neighbouring segments, were relatively common. Malfor-mations at the trunk-tail boundary often include sacralization of pre-and postsacral elements with asymmetrically or symmetrically developed diapophyses, fusion with the posteriormost presacral vertebra, occurrence of postsacral vertebrae , unusual transverse processes at the proximal end of the urostyle, formation of additional zygapophyses, or fusion of elements that normally articulate. Vertebral fusion in the anterior vertebral column (Presacral Vertebrae I+II) has been reported both in evolutionary context and in cases of individual developmental anomalies. Malformations in the middle section of the vertebral column, such as the case of Epidalea calamita reported herein, are rare.
