Amphibians From the Middle Jurassic Balabansai Svita in the Fergana Depression, Kyrgyzstan (Central Asia)

Averianov, A. O.; Martin, Thomas; Skutschas, Pavel P.; Rezvyi, Anton S.; Bakirov, Aizek A.

doi:10.1111/j.1475-4983.2007.00748.x

Cited by 25 publications

(47 citation statements)

References 21 publications

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“…Salientians first appear in the fossil record in the Early Triassic (Rage and Roček 1989;Evans and Borsuk-Białynicka 2009), followed by Gymnophionomorpha in the Early Jurassic (Jenkins et al 2007) and by Caudata in the Middle Jurassic (Evans et al 1988;Averianov et al 2008;Skutschas and Martin 2011). Of these earliest lissamphibians, only the morphology is known in any detail.…”

Section: Introductionmentioning

confidence: 97%

“…Another set of biological data, unexploited so far in these taxa, bone histology, can yield valuable information on the growth pattern, gross physiology and ecologic adaptation of early amphibians. Below, we provide the first histological data on one of these clades, the karaurids, known from Central Asia (Karaurus, Kokartus: Averianov et al 2008;Skutschas and Martin 2011), Britain (Marmorerpeton, Salamander A: Evans et al 1988) and Portugal (cf. Marmorerpeton: Evans, personal observation).…”

Section: Introductionmentioning

confidence: 99%

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Histological study of karaurids, the oldest known (stem) urodeles

et al. 2014

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Little is known about the initial phases of lissamphibian history (before the Cretaceous), because their fossil record is quite scanty. Only the morphology of the earliest members has been investigated, although other sets of data, from bone microanatomy and histology, are known to yield valuable paleobiological information. In the present study, we provide the first histological and microanatomical data on the oldest known stem-urodeles, the karaurids, from the Middle Jurassic. Three humeri from the Upper Bathonian, Oxfordshire, referred to juvenile or subadult individuals of Marmorerpeton and to an unnamed caudate of undetermined (but obviously non-larval) ontogenetic stage, were sampled in order to shed new light on the habitat and ontogeny of these basal caudates. The great compactness of the three humeri suggests that these salamanders were aquatic. The presence of extensive amounts of calcified cartilage in the humeri greatly strengthens the case for the presence of neoteny in these taxa, a suggestion that had initially been made on the basis of a few morphological characters. This constitutes the oldest known occurrence of neoteny in lissamphibians. Finally, bone histology reveals that the growth of Marmorerpeton and the related unnamed caudate was fairly slow and cyclic, a characteristic of extant lissamphibians.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Histological study of karaurids, the oldest known (stem) urodeles

et al. 2014

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“…These fossils come from the Kirtlington locality and are interpreted as possible karaurids (Marjanović and Laurin, 2014). Given the Middle Jurassic age (Bathonian) of this locality (Evans et al, 1988), no older urodele remains are known (Averianov et al, 2008;Evans and Waldman, 1996;Skutschas, 2013). Finally, we also refined our inference model for urodeles (Organ et al, 2011) by adding three new extant urodele taxa for which the genome size is known, in order to yield more reliable paleogenomic estimates.…”

Section: Introductionmentioning

confidence: 97%

Early genome size increase in urodeles

Laurin

Canoville

Struble

et al. 2016

Comptes Rendus Palevol

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a b s t r a c tUrodeles have the largest genomes among extant tetrapods, varying greatly between metamorphic and neotenic species, which have the smallest and the largest genomes of the group, respectively. The evolutionary tempo and mode of genome size expansion in urodeles are poorly documented, especially because genome size does not directly fossilize. Consequently, the ancestral state for genome size, and therefore, the polarity of its evolution in urodeles are uncertain. However, recent studies have demonstrated that osteocyte (lacuna) size is correlated with genome size. Below, we present histological data, on osteocyte lacuna size from one of the oldest known stem-urodeles, Marmorerpeton, from the Middle Jurassic (Bathonian,(166)(167)(168), as well as on five extant urodele species. Our analysis of these taxa, coupled with previously published data, suggests that stem-urodeles had already evolved large genomes, typical of extant urodeles by the Bathonian.

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“…Salamanders first appear in the fossil record in the Middle Jurassic (Bathonian). Remains of the oldest salamanders are known from geographically distant areas such as Western Siberia (Russia), Great Britain and Kyrgyzstan (Evans et al 1988;Nesov, 1988;Evans & Milner, 1994;Evans & Waldman, 1996;Nesov et al 1996;Milner, 2000;Averianov et al 2008;Skutschas & Krasnolutskii, 2011;Skutschas & Martin, 2011;Skutschas, 2013). Notably, the first salamanders in the Bathonian vertebrate assemblages of Western Siberia (Russia) and Great Britain were diverse, and are represented by primitive stem-group taxa and probably also crown-group taxa (Milner, 2000;Skutschas, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Notably, the first salamanders in the Bathonian vertebrate assemblages of Western Siberia (Russia) and Great Britain were diverse, and are represented by primitive stem-group taxa and probably also crown-group taxa (Milner, 2000;Skutschas, 2013). All stem salamanders are usually referred to the family Karauridae, which is considered to be paraphyletic (Evans et al 2005;Averianov et al 2008). According to another opinion, only two taxathe Middle Jurassic (Bathonian) Kokartus honorarius from Kyrgyzstan and the Late Jurassic (Kimmeridgian) Karaurus sharovi from Kazakhstan, constitute the monophyletic Karauridae, and the attribution of any other stem-group salamanders (e.g.…”

Section: Introductionmentioning

confidence: 99%

Long bone histology of the stem salamander Kokartus honorarius (Amphibia: Caudata) from the Middle Jurassic of Kyrgyzstan

Skutschas

Stein

2015

Journal of Anatomy

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Kokartus honorarius from the Middle Jurassic (Bathonian) of Kyrgyzstan is one of the oldest salamanders in the fossil record, characterized by a mixture of plesiomorphic morphological features and characters shared with crown-group salamanders. Here we present a detailed histological analysis of its long bones. The analysis of a growth series demonstrates a significant histological maturation during ontogeny, expressed by the progressive appearance of longitudinally oriented primary vascular canals, primary osteons, growth marks, remodelling features in primary bone tissues, as well as progressive resorption of the calcified cartilage, formation of endochondral bone and development of cartilaginous to bony trabeculae in the epiphyses. Apart from the presence of secondary osteons, the long bone histology of Kokartus is very similar to that of miniaturized temnospondyls, other Jurassic stem salamanders, miniaturized seymouriamorphs and modern crown-group salamanders. We propose that the presence of secondary osteons in Kokartus honorarius is a plesiomorphic feature, and the loss of secondary osteons in the long bones of crown-group salamanders as well as in those of miniaturized temnospondyls is the result of miniaturization processes. Hitherto, all stem salamander long bong histology (Kokartus, Marmorerpeton and 'salamander A') has been generally described as having paedomorphic features (i.e. the presence of Katschenko's Line and a layer of calcified cartilage), these taxa were thus most likely neotenic forms. The absence of clear lines of arrested growth and annuli in long bones of Kokartus honorarius suggests that the animals lived in an environment with stable local conditions.

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Amphibians From the Middle Jurassic Balabansai Svita in the Fergana Depression, Kyrgyzstan (Central Asia)

Cited by 25 publications

References 21 publications

Histological study of karaurids, the oldest known (stem) urodeles

Histological study of karaurids, the oldest known (stem) urodeles

Early genome size increase in urodeles

Long bone histology of the stem salamander Kokartus honorarius (Amphibia: Caudata) from the Middle Jurassic of Kyrgyzstan

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