Comparative analysis of osteoderms across the lizard body

Maliuk, Anastasiia; Marghoub, Arsalan; Williams, Catherine J. A.; Stanley, Edward; Kéver, Loïc; Vickaryous, Matthew; Herrel, Anthony; Evans, Susan E.; Moazen, Mehran

doi:10.1002/ar.25418

Cited by 3 publications

(1 citation statement)

References 47 publications

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“…The distribution and structure of ossified dermal armor among Scincoidea is highly variable 47 , but cycloid, compound osteoderms, encircling the body, occur only in Scincidae 14 , 27 , 48 ; ventral compound osteoderms are also found gerrhosaurs (two gerrhosaurid species also possess dorsal compound osteoderms— Gerrhosaurus skoogi and Cordylosaurus subtessellatus ). Among fossil taxa, only Parmeosaurus scutatus shows some ventral compound osteoderms or duplex osteoderms, formed by two units 41 , but these are more rectangular and arranged in a grid-like pattern, being similar to the dorsal osteoderms of gerrhosaurs and quite unlike the cycloid, imbricate, staggered arrangement of osteoderms of extant skinks.…”

Section: Introductionmentioning

confidence: 99%

Compound osteoderms preserved in amber reveal the oldest known skink

Daza,

Stanley,

Heinicke

et al. 2024

Sci Rep

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Scincidae is one of the most species-rich and cosmopolitan clades of squamate reptiles. Abundant disarticulated fossil material has also been attributed to this group, however, no complete pre-Cenozoic crown-scincid specimens have been found. A specimen in Burmite (99 MYA) is the first fossil that can be unambiguously referred to this clade. Our analyses place it as nested within extant skinks, supported by the presence of compound osteoderms formed by articulated small ostedermites. The specimen has a combination of dorsal and ventral compound osteoderms and overlapping cycloid scales that is limited to skinks. We propose that this type of osteoderm evolved as a response to an increased overlap of scales, and to reduced stiffness of the dermal armour. Compound osteoderms could be a key innovation that facilitated diversification in this megadiverse family.

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Section: Introductionmentioning

confidence: 99%

Compound osteoderms preserved in amber reveal the oldest known skink

Daza,

Stanley,

Heinicke

et al. 2024

Sci Rep

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Review of osteoderm function and future research directions

Ebel,

Herrel,

Scheyer

et al. 2024

Journal of Zoology

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Osteoderms, bone plates in the skin, are widely but discontinuously distributed across the phylogeny of tetrapods. This and their pronounced morphological disparity has inspired many hypotheses on possible osteoderm functions. Most of these have not been systematically studied or summarised based on the published disparate literature. We provide here a comprehensive overview of the current state of knowledge in this field with a focus on extant non‐avian reptiles. We also discuss functions in other extant osteoderm‐bearing taxa and those inferred from the fossil record. The hypotheses are categorised into protection, lifestyle and locomotion, physiology, and visual functions. A comprehensive overview of future directions in this field is provided. With this review, we hope to encourage future research to investigate the functional aspect of osteoderms. This might inspire biomimetics and shed light on the role that osteoderm expression may have played in shaping present‐day biodiversity.

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New diverse amphibian and reptile assemblages from the late Neogene of northern Greece provide novel insights into the emergence of extant herpetofaunas of the southern Balkans

Georgalis,

Villa,

Ivanov

et al. 2024

Swiss J Palaeontol

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We here describe abundant new fossil material of amphibians and reptiles from different late Neogene localities of northern Greece: the Early Pliocene (MN 14) of Spilia 0, Spilia 1, and Spilia 2; the Early Pliocene (MN 15) of Spilia 3, Spilia 4, Spilia 5, and Vevi; and the Late Miocene or Pliocene of Chalicorrema and Rema Marmara. These new late Neogene herpetofaunas are highly diverse, documenting a considerably rich herpetofauna allowing the identification of at least two salamander, seven frog, two turtle, seven lizard, and eight snake taxa. Salamanders are represented by the salamandrid genera Ommatotriton and Ichthyosaura. Frogs are represented by the bombinatorid Bombina, the discoglossids Latonia cf. ragei and Latonia sp., the pelobatid Pelobates aff. praefuscus and Pelobates sp., the ranids Pelophylax and Rana cf. dalmatina, the hylid Hyla gr. arborea, and the bufonid Bufotes gr. viridis. Turtles are represented by the emydid Emys and an indeterminate geoemydid. Lizards are represented by the scincid Ophiomorus, two lacertids (one of which potentially pertaining to Lacerta), amphisbaenians, agamids, the anguid Pseudopus, and a potential varanid. Snakes are represented by the erycid Eryx, the natricid Natrix aff. rudabanyaensis, a small-sized elapid, an “Oriental viper”, the colubriforms Periergophis and Paraxenophis, as well as two further distinct but still indeterminate morphotypes of colubriforms. For the material from Spilia tentatively referred to Ommatotriton, this is only the third occurrence in the fossil record globally. The new material of Ichthyosaura and Bombina mark the first documentation of these genera in the Greek fossil record. Abundant cranial and postcranial material from Spilia is tentatively referred to Latonia ragei, a taxon previously known from the Early Miocene of Western Europe. The new record of Pelobates represents the oldest documented occurrences of the genus in the Greek fossil record. Interestingly, the Pelobates from Spilia bears much resemblance to an extinct taxon, Pelobates aff. praefuscus, which is otherwise known from the Late Miocene of the Caucasus, and not to the extant species that currently inhabits the area. The identification of Pelophylax and Rana adds to the rather poor Neogene record of ranids from Greece. Particularly for the case of Rana cf. dalmatina from Spilia 4, this corresponds to the only documented occurrence of this extant taxon in the Greek fossil record. Similarly, the identification of Hyla gr. arborea in Spilia 1, Spilia 3, and Spilia 4, marks only the third documented occurrence of this genus in the Greek fossil record. The Bufotes material from Spilia 1, Spilia 3, and Spilia 4 represents the first documented fossil occurrence of the extant Bufotes viridis complex in Greece. The material of Emys gr. orbicularis from Vevi marks the only known pre-Quaternary record of the genus in Greece and one of the only few Neogene members of the genus known from Europe. The scincid Ophiomorus is identified in Spilia 4, known from several cranial and postcranial remains, well outside the extant range of the genus. Practically, the Spilia Ophiomorus is only the fourth known fossil occurrence of this extant genus globally and also represents one of its oldest known occurrences. Material from Spilia 1 and Spilia 3 is tentatively referred to cf. Lacerta sp., and this would mark the first known occurrence of this emblematic extant genus in the Greek fossil record, denoting the presence of the genus since at least the Early Pliocene. The new amphisbaenian specimens from Spilia 4 add to the recently described single vertebra from the same locality, and represent the youngest occurrence of amphisbaenians from continental Eastern Europe. The new agamid material from Vevi and Chalicorrema add substantially to the record of this group, which was in Greece so far known exclusively from the latest Miocene/earliest Pliocene of Maramena. A similarly important addition is the record of Pseudopus from Spilia 4, as this genus had been known in the Greek fossil record only from a very few localities. The potential varanid from Spilia represents one of the few Pliocene occurrences of this group in Europe. We identify Natrix aff. rudabanyaensis among the material from Spilia 0, Spilia 4, and Vevi, adding to the previously known record of this taxon from Maramena, however, its precise species level assignment should await a revision of Neogene European Natrix spp. The find of a small elapid from Spilia 4 represents the youngest occurrence of a coral snake from Europe, extending their statigraphic range up to the Early Pliocene (MN 14). Periergophis and Paraxenophis, two bizarre snakes, so far exclusively known from their type locality in Maramena, could be also present here, even if tentatively identified. Most notably, the new material from these localities comprises forms that are now extinct (e.g., Periergophis and Paraxenophis) or extirpated from Europe (e.g., Latonia, Varanidae, Elapidae) but at the same time also loudly attests the emergence of the extant genera that dominate the extant herpetofaunas of Greece (Ichthyosaura, Bombina, Pelobates, Pelophylax, Rana, Hyla, Bufotes, Emys, Ophiomorus, Lacerta, Pseudopus, Eryx, and Natrix), for some of which their fossil record is documented here for the first time in the area.

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Comparative analysis of osteoderms across the lizard body

Cited by 3 publications

References 47 publications

Compound osteoderms preserved in amber reveal the oldest known skink

Compound osteoderms preserved in amber reveal the oldest known skink

Review of osteoderm function and future research directions

New diverse amphibian and reptile assemblages from the late Neogene of northern Greece provide novel insights into the emergence of extant herpetofaunas of the southern Balkans

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