Developmental Changes in the Orientation of the Anuran Jaw Suspension

Wassersug, Richard J.; Hoff, Karin

doi:10.1007/978-1-4615-6968-8_5

Cited by 64 publications

(24 citation statements)

References 50 publications

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“…Note the major differences between the position of the craniovertebral joint and the caudal (i.e., the articular) end of the jaws in the different species. The magnitude of the metamorphic transformation in the length of the lower jaw determines the gape at the end of metamorphosis (Wassersug & Hoff, ). The experimental manipulation shown in the oval at the bottom of the figure demonstrates how TH can alter the length of the jaws and their position in relation to the caudal end of the skull as indicated by the position of the craniovertebral joint.…”

Section: Discussionmentioning

confidence: 99%

Differences in responsiveness and sensitivity to exogenous disruptors of the thyroid gland in three anuran species

2019

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Anuran larval development comprises tissues/organs/systems that are: exclusively of larvae, able to be remodelled, and those of postmetamorphic stages. Also, the anuran larval development is characterized by inter‐related parameters: time, size and shape forming part of growth and differentiation. The anuran metamorphosis starts when growth and differentiation achieve a threshold that differs among species since it is regulated by a number of external (environmental) and internal (hormonal) processes. Here we explore the consequences of exogenous disruptors on the thyroid gland (e.g., methimazole and thyroxine as T4) of three species by immersing premetamorphic tadpoles in predetermined concentrations of the disruptors for short periods (10 or 16 days). The species were Pleurodema borellii, Leptodactylus chaquensis, and Dermatonotus muelleri, which all breed in small temporary ponds during the summer, but differ in their ecomorphology. The experiments were conducted to evaluate the effects of these substances on larval development (based in Gosner larval stages), morphometric variation in body parameters (snout‐vent and total length by larval stages), and thyroid gland histopathology at the end of the assays. In P. borelli and L. chaquensis, methimazole produces significant increment of size measurements (nonparametric Kruskal–Wallis, p < .05) during stages of digit differentiation and induced thyroid gland hypertrophy. In the three species, T4 exposure accelerated limb development and caused atrophy of thyroid gland. Prolonged T4 exposure in L. chaquensis and D. muelleri triggered metamorphic transformation in the gut and skull cartilages. Discussion about interspecific differences in responsiveness and sensitivity elucidates the importance of hormonal signals to morphological evolution.

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Section: Discussionmentioning

confidence: 99%

Differences in responsiveness and sensitivity to exogenous disruptors of the thyroid gland in three anuran species

2019

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“…The corpus is short and stout and, thus, the jaw articulation is located ventral to the eye. In all other anuran larvae, the palatoquadrate is considerably longer, oriented in a shallow angle (lateral view), and the jaw articulation is located well anterior to the eye (Wassersug and Hoff, 1982).…”

Section: Mandibulolabialis Inserting In Soft Tissue Of Lipmentioning

confidence: 99%

Phylogeny of frogs as inferred from primarily larval characters (Amphibia:Anura)★

Haas

2003

Cladistics

117

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This paper presents larval evidence and evaluates its contribution to the discussion of frog phylogeny; 136 larval characters, 6 reproductive biology characters, and 14 adult morphology characters were scored for 81 frog and 4 caudate species. More than 90% of the data matrix entries represent original data derived from personal direct examination of specimens. Some larval characters are described for the first time and many others have not been assessed for specific taxa or in a broad phylogenetic context before. Homoplasy appears common in this and other amphibian morphological data sets. The data supported and confirmed various wellknown clades, among others the Anura, Bufonidae, Ceratophryinae, Discoglossidae, Dendrobatidae, Hyperoliidae, Microhylidae, South American microhylids, Phyllomedusinae, Pseudinae, Pipoidea, Pipidae, and Scoptanura. The Ascaphidae was sister group to all other anurans and the Pipoidea was placed more basally than in some previous analyses. The Eurasian pelobatids formed a clade, whereas Spea and Pelodytes did not group robustly with them. Pelobatoid frogs emerged as a paraphyletic ''transitional'' assemblage including Heleophryne. The resolution of basal neobatrachian splits remained labile, although some subclades within the Neobatrachia were robustly supported. The ''Hylidae'' was paraphyletic, and hyline species were paraphyletic with respect to the Pseudinae. Hemisus clearly was in a clade with the Hyperoliidae and is proposed to be included in that family. Scaphiophryne was confirmed as basal taxon within the Microhylidae. Compared to the larval stages of the most recent common ancestor of anurans, members of the Scoptanura (microhylids except scaphiophrynines) have accumulated the highest number of apomorphic character states in anuran evolution.

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“…Frogs almost certainly have evolved from an ancestor, possibly similar to branchiosaurs (Caroll et al, 1999), in which larval and postlarval stages were not as dramatically different as in extant forms (Wassersug and Hoff, 1982;Fritsch, 1990;Hanken, 1999). This condition is still seen in the extant caudate and gymnophione amphibians.…”

Section: Evolution Of Anuran Larval Jaw Musclesmentioning

confidence: 99%

Mandibular arch musculature of Anuran tadpoles, with comments on homologies of amphibian jaw muscles

2000

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Developmental Changes in the Orientation of the Anuran Jaw Suspension

Cited by 64 publications

References 50 publications

Differences in responsiveness and sensitivity to exogenous disruptors of the thyroid gland in three anuran species

Differences in responsiveness and sensitivity to exogenous disruptors of the thyroid gland in three anuran species

Phylogeny of frogs as inferred from primarily larval characters (Amphibia:Anura)★

Mandibular arch musculature of Anuran tadpoles, with comments on homologies of amphibian jaw muscles

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