An assemblage of lizards from the Early Cretaceous of Japan

Evans, Susan E.; Matsumoto, Ryoko

doi:10.26879/519

Cited by 10 publications

(6 citation statements)

References 54 publications

(127 reference statements)

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“…9), although the state of preservation means that other foramina could have been missed. This presents a greater degree of variation than has been recognized in other titanosaur taxa, which show a consistent posterior location of the pneumatic foramina ( Bonitasaura , Gallina & Apesteguía, 2015; Gondwanatitan , Kellner & de Azevedo, 1999; Lirainosaurus , Díez Díaz et al, 2013; Malawisaurus , Gomani, 2005; Maxakalisaurus , Kellner et al, 2006; Mnyamawamtuka , Gorscak & O'Connor, 2019; Overosaurus , Coria et al, 2013). Further examination with attention to serial position of the ribs will be needed to confirm whether TMM 45891 is truly unique among titanosaurs in this respect.…”

Section: Discussionmentioning

confidence: 66%

Patterns and function of pneumaticity in the vertebrae, ribs, and ilium of a titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Texas

Fronimos

2023

Journal of Vertebrate Paleontology

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Many sauropod dinosaurs exhibit extensive postcranial skeletal pneumaticity that may have facilitated the evolution of extreme body sizes. Among titanosauriforms, complex, irregularly branching camellate chambers are found throughout the presacral vertebral column, often invading the ribs and ilium as well. To explore the function of these camellae, including reduction in bone volume, pneumaticity was examined in a titanosaur sauropod from the Upper Cretaceous Black Peaks Formation of Big Bend National Park, Texas, that includes pneumatic dorsal ribs and ilia. Using natural breaks to non-destructively observe the internal structure, patterns of camellate pneumaticity are described for the dorsal vertebrae, ribs, and ilium. The space occupied by camellae is quantified as the airspace proportion, which is reported here in a sauropod ilium for the first time. Airspace proportions exceed 70% in parts of the dorsal vertebrae and ilium, with lower values near the cotyles of the vertebral centra and the acetabulum. Values in the ribs decrease distally. These values are not appreciably different from those of sauropods with simpler camerate pneumaticity. If camellae did not offer greater weight reduction than camerae, they may have enhanced structural strength, as the chambers appear to align with stress in the vertebral centra and ilium. Apneumatic trabecular bone around the acetabulum, preacetabular process, and postzygapophyses, however, may indicate stresses too great for camellate bone to bear, although an ontogenetic influence cannot be ruled out.

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Section: Discussionmentioning

confidence: 66%

Patterns and function of pneumaticity in the vertebrae, ribs, and ilium of a titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Texas

Fronimos

2023

Journal of Vertebrate Paleontology

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“…Allowing for immaturity, Retinosaurus also differs from other roughly contemporaneous fossil squamates known from Europe, Asia, and the Americas in the following combination of characters: depressed (box-shaped) skull; nasal process of unpaired premaxilla long, almost reaching frontals; anterior width of nasals exceeds nasofrontal joint width; elongate frontal plate only weakly emarginated by orbits (contra Eichstaettisaurus Kuhn 34 , Liushusaurus Evans and Wang 35 , Meyasaurus Vidal 36 , Huehuecuetzpalli Reynoso 37 ); anteriorly well-developed subolfactory processes that extend toward the ventral midline; interdigitated fronto-parietal suture (as in Yabeinosaurus Endo and Shikama 38 , Sakurasaurus Evans and Manabe 39 , but contra Huehuecuetzpalli , Tepexisaurus and extant xantusiids), with parietal tabs underlying frontals; paired parietals lacking ventral fossa for supraoccipital processus ascendens (contra Yabeinosaurus, Sakurasaurus, Kuroyuriella Evans and Matsumoto 40 , Hoyalacerta Evans and Barbadillo 41 , Dorsetisaurus Hoffstetter 42 , Purbicella Evans et al . 43 , Jucaraseps Bolet and Evans 44 , Huehuecuetzpalli , paramacellodids, polyglyphanodontians); lacrimal bone absent (contra Purbicella ); palatal dentition absent (contra e.g., Dalinghosaurus Ji 45 , Yabeinosaurus, Purbicella ); ectopterygoid with hooked posterior process that is laterally exposed (as Tepexisaurus Reynoso and Callison 46 ); ectopterygoid contacts palatine to exclude the maxilla from the lateral margin of the suborbital fenestra; large, deeply recessed lateral opening of the recessus scalae tympani; jaw joint lies well anterior to level of occipital condyle (contra e.g., Huehuecuetzpalli , Tepexisaurus ); open Meckel’s groove (contra derived state in extanct xantusiids); retention of a separate splenial and angular (contra derived state in extant xantusiids); homodont pleurodont dentition of moderately pointed and unicuspid tooth crowns (contra bicuspid as in Meyasaurus, Hakuseps Evans and Matsumoto 40 , Pedrerasaurus Bolet and Evans 47 ; multicuspid in Asagaolacerta Evans and Matusmoto 40 and many polyglyphanodontians including Kuwajimalla Evans and Manabe 48 ; robust and striated, as in Saurillodon Estes 49 ; truncated with anteroposteriorly directed apical groove in contogeniids, or rounded in Gueragama Simões et al 50 ); splenial short, not reaching mid-point of dentary; long straight retroarticular process (e.g., contra Meyasaurus, Tepexisaurus, Huehuecuetzpalli ); zygapophysial facet between atlas and axis; first and second intercentrum small and not in contact with each other; cruciform interclavicle with long anterior ...…”

Section: Systematic Palaeontologymentioning

confidence: 99%

A new Early Cretaceous lizard in Myanmar amber with exceptionally preserved integument

Čerňanský

Stanley

Daza

et al. 2022

Sci Rep

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We here report on a well-preserved juvenile lizard specimen in Albian amber (ca. 110 mya) from the Hkamti site (Myanmar). This new taxon is represented by an articulated skull and the anterior portion of the trunk, including the pectoral girdle and forelimbs. The scleral ossicles and eyelid are also visible, and the specimen exhibits pristine detail of the integument (of both head and body). In a combined molecular and morphological analysis, it was consistently recovered as a scincoid lizard (Scinciformata), as sister to Tepexisaurus + Xantusiidae. However, the phylogenetic position of the new taxon should be interpreted with caution as the holotype is an immature individual. We explored the possibility of miscoding ontogenetically variable characters by running alternative analyses in which these characters were scored as missing data for our taxon. With the exception of one tree, in which it was sister to Amphisbaenia, the specimen was recovered as a Pan-xantusiid. Moreover, we cannot rule out the possibility that it represents a separate lineage of uncertain phylogenetic position, as it is the case for many Jurassic and Cretaceous taxa. Nonetheless, this fossil offers a rare opportunity to glimpse the external appearance of one group of lizards during the Early Cretaceous.

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“…The position of this large and important fossil group therefore remains problematic, but it is attributed to Teiioidea in Figure 2.1. The earliest attributed polyglyphanodonts are Kuwajimalla kagaensis [54] and Asagaolacerta tricuspidens [89] from the Tetori Formation (Barremian-Aptian, Japan). An unnamed lizard specimen preserved in amber (Albian-Cenomanian, Myanmar) was also described as a crown lacertoid [64], but this attribution was based primarily on comparison with polyglyphanodonts.…”

Section: Lacertoideamentioning

confidence: 99%

The Origin and Early Diversification of Squamates

Evans¹

2022

The Origin and Early Evolutionary History of Snakes

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Squamata, the group that encompasses snakes, lizards, and amphisbaenians, is the largest (>10,500 sp.) and most disparate group of modern reptiles. Extant squamates are distributed over all but the coldest parts of the world; range in size (snout-vent length, SVL) from millimetres to metres; and show a diversity of diets, shapes, locomotor patterns, and reproductive strategies. Snakes (Serpentes) account for roughly 35 per cent of all extant squamate species and their origin and relationships, which have long intrigued herpetologists, are the focus of this volume. This chapter aims to provide a foundation for subsequent chapters, by reviewing what is currently known of the early stages of squamate evolution and diversification.Most researchers recognize eight extant major squamate clades (Fig. 2.1): Dibamidae; Gekkota; Scincoidea (=Scinciformata [1]), encompassing Xantusiidae, Scincidae, and Cordyliformes; Lacertoidea (=Laterata [1]), encompassing Lacertidae and Teiioidea; Amphisbaenia; Iguania; Anguimorpha; and Serpentes. Although Camp [2] considered Gekkota to be primitive squamates (part of his Ascalabota), the first comprehensive cladistic analysis [3], based on morphological characters, placed Iguania as the sister group of other squamates (Scleroglossa). Within Scleroglossa, Estes et al. [3] united Scincoidea + Lacertoidea in Scincomorpha, and Scincomorpha + Anguimorpha as Autarchoglossa. The position of three limb-reduced clades, Dibamidae, Amphisbaenia, and Serpentes, was unresolved within Scleroglossa. The topology of Estes et al. [3] remained the working hypothesis for most herpetologists until 2004 with the publication of phylogenies based on molecular data [4,5]. The molecular trees placed Gekkota rather than Iguania as the sister group of other squamates (invalidating Scleroglossa), with Scincoidea, and then Lacertoidea (including Amphisbaenia) as successive outgroups to a Toxicofera that

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An assemblage of lizards from the Early Cretaceous of Japan

Cited by 10 publications

References 54 publications

Patterns and function of pneumaticity in the vertebrae, ribs, and ilium of a titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Texas

Patterns and function of pneumaticity in the vertebrae, ribs, and ilium of a titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Texas

A new Early Cretaceous lizard in Myanmar amber with exceptionally preserved integument

The Origin and Early Diversification of Squamates

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