Caudal vertebral development and morphology in three salamanders with complex life cycles (Ambystoma jeffersonianum,Hemidactylium scutatum, andDesmognathus ocoee)

Babcock, Sharon K.; Blais, Jennifer L.

doi:10.1002/1097-4687(200102)247:2<142::aid-jmor1009>3.0.co;2-y

Cited by 20 publications

(8 citation statements)

References 33 publications

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“…From a lateral view, the haemal arch on the last caudosacral vertebrae is smaller and directed more ventrally than the haemal arch on the first caudal vertebra. It also exhibits a greater haemal spine angle than those on subsequent caudal vertebrae (Babcock and Blais 2001). Images, vertebral counts and centrum measurements were taken and caudal morphology described using a Nikon SMZ1000 with Spot Insight Imaging software.…”

Section: Specimen Preparation and Measurementsmentioning

confidence: 99%

“…On the other hand, direct-developing Batrachoseps adds at a constant rate through life, resulting in approximately one new vertebra per 2 mm of TL (Dickie 1999). Many of the biphasic species add a large number of new vertebrae either soon after hatching or following metamorphosis (Vaglia et al, 1997;Babcock and Blais 2001;current study). The padeomorphic pattern remains elusive, but our initial data suggest that A. mexicanum adds vertebrae at a steady rate throughout life.…”

Section: Do Salamanders Add Vertebrae Throughout the Life Cycle?mentioning

confidence: 99%

“…Specifically, vertebrate species known to add segments postembryonically do so via terminal addition to the tail bud. (Vaglia et al 1997;Babcock and Blais 2001). Our research investigates ongoing addition of caudal vertebrae in salamanders, with current emphasis on species within the genus Eurycea (Plethodontidae; Hemidactyliini; Ryan and Bruce 2000;Chippindale et al 2004) as well as one Ambystoma species, Ambystoma mexicanum (Ambystomatidae).…”

Section: Introductionmentioning

confidence: 99%

“…Yet other salamanders have paedomorphic life cycles where the sexually mature adults retain larval features, such as gills and a laterally compressed, finned tail. Species thus far shown to continually elongate via the addition of caudal segments are found across all life-history patterns, represent different families, inhabit different environments and exhibit different tail morphologies (Noble 1931;Jockusch 1997;Vaglia et al 1997;Babcock and Blais 2001) (Table 1). Many of the species that continually elongate also undergo tail autotomy, or 'voluntary' dropping of the tail when threatened by predation.…”

Section: Introductionmentioning

confidence: 99%

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Evolving possibilities: postembryonic axial elongation in salamanders with biphasic (Eurcyea cirrigera, Eurycea longicauda, Eurycea quadridigitata) and paedomorphic life cycles (Eurycea nana and Ambystoma mexicanum)

Vaglia¹,

White²,

Case³

2010

Acta Zoologica

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Typically the number of vertebrae an organism will have post-embryonically is determined during embryogenesis via the development of paired somites. Our research investigates the phenomenon of post-embryonic vertebral addition in salamander tails. We describe body and tail growth, and patterns of postsacral vertebral addition and elongation in context with caudal morphology for four plethodontids (Eurycea), and one ambystomatid. Eurycea nana and A. mexicanum have paedomorphic life cycles; E. cirrigera, E. longicauda and E. quadridigitata are biphasic. Specimens were collected, borrowed and/or purchased, and cleared and stained for bone and cartilage. Data collected include snout-vent length (SVL), tail length (TL), vertebral counts and centrum lengths. Eurycea species with biphasic life cycles had TLs that surpassed SVL following metamorphosis. Tails in paedomorphic species elongated but rarely exceeded body length. Larger TLs were associated with more vertebrae and longer vertebrae in all species. We observed that rates of postsacral vertebral addition varied little amongst species. Regional variation along the tail becomes prominent following metamorphosis in biphasic developers. In all species vertebrae in the posterior one-half of the tail taper towards the tip. We suggest a developmental link might exist between the ability to continually add vertebrae and regeneration in salamanders.

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Section: Specimen Preparation and Measurementsmentioning

confidence: 99%

Section: Do Salamanders Add Vertebrae Throughout the Life Cycle?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evolving possibilities: postembryonic axial elongation in salamanders with biphasic (Eurcyea cirrigera, Eurycea longicauda, Eurycea quadridigitata) and paedomorphic life cycles (Eurycea nana and Ambystoma mexicanum)

Vaglia¹,

White²,

Case³

2010

Acta Zoologica

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“…Accordingly, parallels are easy to pick out between caudal vertebral development in urodelean larvae and megophryid tadpoles. For example, caudal centra form as complete, perichordal spools in Eurycea bislineata (Wake and Lawson 1973) and Hemidactylium scutatum (Vaglia et al 1997;Babcock and Blais 2001) as in Leptobrachella mjobergi. The Bogenbasen mode, as seen in Megophrys and Xenophrys species, instead resembles caudal vertebral formation in the Hynobiidae.…”

Section: Interpreting the Variation: Evolutionary Considerationsmentioning

confidence: 99%

Bony‐tailed tadpoles: the development of supernumerary caudal vertebrae in larval megophryids (Anura)

Handrigan

Haas

Wassersug

2007

Evolution and Development

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The axial skeleton in most anuran families consists of or=7). Tadpoles from each genus are typically found in streams, where their extended caudal skeleton anchors muscles that facilitate tadpoles wiggling between plant debris and rocks or even burrowing into the stream bed. The extra centra of megophryids ossify differently in each genus. In Leptobrachella and Ophryophryne, the caudal centra ossify around the entire notochord, whereas in Megophrys and Xenophrys each develops from dorsal and ventral pairs of ossifications that expand to meet each other. The evolutionary loss of caudal centra, an apomorphic anuran trait, is reversed in larval megophryids and confirms that the machinery for caudal vertebral development has been retained in some modern anurans. A likely driving force in the reappearance of the trait in megophryids is the selective pressure associated with a riparian lifestyle.

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Heterochrony in limb evolution: developmental mechanisms and natural selection

et al. 2009

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The tetrapod limb provides several examples of heterochrony-changes in the timing of developmental events. These include species differences in the sequence of skeletal chondrogenesis, in gene transcription in the developing limbs, and in the relative time at which forelimb and hind limb buds develop. Here, we examine (i) phylogenetic trends in limb heterochrony; (ii) changes in developmental mechanisms that may lead to heterochrony; and (iii) the possible role that heterochrony plays in generating adaptive traits. We analyze the published literature and present preliminary data on turtle (Emys orbicularis) and bat (Rousettus amplexicaudatus) limb development. Teleosts, marsupials, and some urodeles show extreme timing differences between forelimb (or pectoral fin) and hind limb (or pelvic fin) development; this heterochrony may, in some cases, be adaptive. Published data on limb chondrogenesis reveal sequence elements that are strongly conserved (possibly owing to constraints); and others that vary between higher taxa (for unknown reasons). We find little evidence that chondrogenic sequences are modified by selection for limb functional traits. There are a few examples of developmental mechanisms that may be modified under heterochrony to produce adaptive changes in the limb (e.g. some cases of hyperphalangy or limb reduction). In conclusion, numerous examples of limb heterochrony have been recorded. However, few cases are obviously adaptive. Indeed, current data and methodologies make it difficult to identify the developmental changes, or selective pressures, that may underlie limb heterochrony. More integrative studies, including studies of heterochrony within populations, are needed to assess the role of timing shifts in limb evolution.

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Caudal vertebral development and morphology in three salamanders with complex life cycles (Ambystoma jeffersonianum,Hemidactylium scutatum, andDesmognathus ocoee)

Cited by 20 publications

References 33 publications

Evolving possibilities: postembryonic axial elongation in salamanders with biphasic (Eurcyea cirrigera, Eurycea longicauda, Eurycea quadridigitata) and paedomorphic life cycles (Eurycea nana and Ambystoma mexicanum)

Evolving possibilities: postembryonic axial elongation in salamanders with biphasic (Eurcyea cirrigera, Eurycea longicauda, Eurycea quadridigitata) and paedomorphic life cycles (Eurycea nana and Ambystoma mexicanum)

Bony‐tailed tadpoles: the development of supernumerary caudal vertebrae in larval megophryids (Anura)

Heterochrony in limb evolution: developmental mechanisms and natural selection

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