Evolution of Facultative Paedomorphosis in Salamanders

Whiteman, Howard H.

doi:10.1086/418540

Cited by 171 publications

(253 citation statements)

References 79 publications

Supporting

Mentioning

236

Contrasting

Order By: Relevance

“…1;Whiteman 1994;Denoël et al 2005). The expression of each morph is considered to be a response to the individual's expected success in the aquatic versus terrestrial environment (Wilbur and Collins 1973).…”

Section: Introductionmentioning

confidence: 99%

“…The expression of each morph is considered to be a response to the individual's expected success in the aquatic versus terrestrial environment (Wilbur and Collins 1973). Facultative paedomorphosis is characterized as an environmental threshold trait, i.e., there is genetic variation with an environmental trigger (Harris 1987;Harris et al 1990;Roff 1996), and there is considerable support for the hypothesis that the origin and maintenance of facultative paedomorphosis is a result of selection (reviewed in Whiteman 1994;Denoël et al 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Two major mechanisms have been proposed for explaining how environmental conditions can select for the production and maintenance of facultative paedomorphosis in salamanders (Whiteman 1994; Table 1). The "paedomorph advantage" mechanism assumes that paedomorphosis is selected when growing conditions are better in the aquatic environment (e.g., lower conspecific densities, higher food levels, optimal temperatures, and/or lower risk of predation) than in the terrestrial environment.…”

Section: Introductionmentioning

confidence: 99%

“…The paedomorph advantage hypothesis predicts that paedomorphosis will be negatively related to population size structure, as estimated by size variation; as size variation increases, a greater proportion of larvae should metamorphose to escape competition with larger individuals. Numerous field and experimental studies support the idea that the development of paedomorphs is an adaptive response to good growth/survival conditions in the aquatic environment (Whiteman 1994;Denoël et al 2005). Alternatively, the "best of a bad lot" mechanism asserts that paedomorphosis arises as a default strategy when the growing conditions are so poor that larvae cannot reach the minimum critical size for metamorphosis (Wilbur and Collins 1973;Wilbur 1980).…”

Section: Introductionmentioning

confidence: 99%

“…Best of a bad lot paedomorphosis is predicted to be positively density-dependent, with the frequency of paedomorphosis increasing as salamander density increases, and positively related to population size structure, as more larvae are forced into paedomorphosis because of competition with larger individuals. Fewer empirical data are consistent with this mechanism as compared to the paedomorphic advantage (Whiteman 1994;Denoël et al 2005Denoël et al , 2007Doyle and Whiteman 2008).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Larval growth in polyphenic salamanders: making the best of a bad lot

et al. 2011

View full text Add to dashboard Cite

Polyphenisms are excellent models for studying phenotypic variation, yet few studies have focused on natural populations. Facultative paedomorphosis is a polyphenism in which salamanders either metamorphose or retain their larval morphology and eventually become paedomorphic. Paedomorphosis can result from selection for capitalizing on favorable aquatic habitats (paedomorph advantage), but could also be a default strategy under poor aquatic conditions (best of a bad lot). We tested these alternatives by quantifying how the developmental environment influences the ontogeny of wild Arizona tiger salamanders (Ambystoma tigrinum nebulosum). Most paedomorphs in our study population arose from slow-growing larvae that developed under high density and size-structured conditions (best of a bad lot), although a few faster-growing larvae also became paedomorphic (paedomorph advantage). Males were more likely to become paedomorphs than females and did so under a greater range of body sizes than females, signifying a critical role for gender in this polyphenism. Our results emphasize that the same phenotype can be adaptive under different environmental and genetic contexts and that studies of phenotypic variation should consider multiple mechanisms of morph production.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Larval growth in polyphenic salamanders: making the best of a bad lot

et al. 2011

View full text Add to dashboard Cite

show abstract

Development and Evolution

Schoch¹

2014

Amphibian Evolution

View full text Add to dashboard Cite

Synapsids and sensitivity: Broad survey of tetrapod trigeminal canal morphology supports an evolutionary trend of increasing facial tactile specialization in the mammal lineage

Miyamae,

Benoit,

Ruf

et al. 2024

The Anatomical Record

View full text Add to dashboard Cite

The trigeminus nerve (cranial nerve V) is a large and significant conduit of sensory information from the face to the brain, with its three branches extending over the head to innervate a wide variety of integumentary sensory receptors, primarily tactile. The paths of the maxillary (V2) and mandibular (V3) divisions of the trigeminus frequently transit through dedicated canals within the bones of the upper and lower jaws, thus allowing this neuroanatomy to be captured in the fossil record and be available to interpretations of sensory ability in extinct taxa. Here, we use microCT and synchrotron scans from 38 extant and fossil species spanning a wide phylogenetic sample across tetrapods to investigate whether maxillary and mandibular canal morphology can be informative of sensory biology in the synapsid lineage. We found that in comparison to an amphibian and sauropsid outgroup, synapsids demonstrate a distinctive evolutionary pattern of change from canals that are highly ramified near the rostral tip of the jaws to canals with increasingly simplified morphology. This pattern is especially evident in the maxillary canal, which came to feature a shortened infraorbital canal terminating in a single large infraorbital foramen that serves as the outlet for branches of V2 that then enter the soft tissues of the face. A comparison with modern analogues supports the hypothesis that this morphological change correlates to an evolutionary history of synapsid‐specific innovations in facial touch. We interpret the highly ramified transitional form found in early nonmammalian synapsids as indicative of enhanced tactile sensitivity of the rostrum via direct or proximal contact, similar to tactile specialists such as probing shorebirds and alligators that possess similar proliferative ramifications of the maxillary and mandibular canals. The transition toward a simplified derived form that emerged among Mid‐Triassic prozostrodont cynodonts and is retained among modern mammals is a unique configuration correlated with an equally unique and novel tactile sensory apparatus: mobile mystacial whiskers. Our survey of maxillary and mandibular canals across a phylogenetic and ecological variety of tetrapods highlights the morphological diversity of these structures, but also the need to establish robust form‐function relationships for future interpretations of osteological correlates for sensory biology.

show abstract

Evolution of Facultative Paedomorphosis in Salamanders

Cited by 171 publications

References 79 publications

Larval growth in polyphenic salamanders: making the best of a bad lot

Larval growth in polyphenic salamanders: making the best of a bad lot

Development and Evolution

Synapsids and sensitivity: Broad survey of tetrapod trigeminal canal morphology supports an evolutionary trend of increasing facial tactile specialization in the mammal lineage

Contact Info

Product

Resources

About