Content uploaded by Kevin de Queiroz
Author content
All content in this area was uploaded by Kevin de Queiroz on Aug 29, 2014
Content may be subject to copyright.
A preview of the PDF is not available
Phylogenetic Relationships within Squamata
Figures
Figures - uploaded by Kevin de Queiroz
Author content
All figure content in this area was uploaded by Kevin de Queiroz
Content may be subject to copyright.
... The teeth of Paleochelco occultato are medially concave and spaced closer to each other, and have evident replacement pits at their bases ), which are not observed here. The mode of pleurodont implantation differs from teiioids (subpleurodont), in which the teeth are surrounded by heavy deposits of cementum (Estes et al. 1988;Nydam and Cifelli 2002). Based on these observations, MML-PV 1066 is tentatively assigned to Scincoidea. ...
... Only one foramen is preserved in MML-PV 1065, but the presence of two openings is inferred since the size and placement of the foramen in the premaxillary process, which is located in a distinct groove bordered medially by a well-developed crista transversalis, matches the placement and morphology of the subnarial arterial foramen observed in several iguanians with two openings (Smith 2009b(Smith , 2011, and the anterior superior alveolar foramen is typically located close to or at the base of the facial process ( Figure 4D), a region that is not preserved in MML-PV 1065. A weak supradental shelf is common in iguanians (Estes et al. 1988), however the size of the supradental shelf throughout the maxilla remains unknown. Only few traits that indicate iguanian affinities are present, since the specimen is known only from a small fragment, but pleurodontan affinities are further supported by the presence of pleurodont dentition consisting of robust, slightly conical teeth, with blunt crowns and without defined accessory cusps, as observed in Leiosauridae ( Figure 3F; Van Devender 1977; Albino et al. 2020). ...
... It further differs from both by its smaller size. LATERATA Vidal andHedges, 2005 TEIIOIDEA Estes, de Queiroz, andGauthier, 1988 Family indet. (Figure 4) Referred specimen MML-PV 1064, isolated fragment of right maxilla. ...
... Aff. Glyptosaurus walbeckensis lacks the following derived characters of Anguioidea (Estes et al. 1988;Gauthier et al. 2012): the splenial anterior inferior alveolar foramen is located between the splenial and the dentary (usually marked by the splenial spine) and the Meckelian canal opens ventrally in the anterior region (not medially for most of length). Moreover, the sulcus dentalis is present, whereas in anguimorphs, the dental crest is shallow and extends medioventrally. ...
... The specimen MLU.GeoS.4059 represents a lacertid since it exhibits the synapomorphies of the family (Estes et al. 1988;Gauthier et al. 2012), such as sulcus dentalis and lateral overlap of the posterodorsal margin of the dentary by the coronoid. The tooth morphology also indicates a lacertid rather than other groups: presence of bicuspid teeth, weak striations and sometimes a weakly-developed lingual cusp is common among members of Lacertidae, including Lacerta (see Kosma 2004;Čerňanský and Syromyatnikova 2019). ...
... In our analysis, in any case, this Paleocene taxon was never recovered as an amphisbaenian. According to morphological data, many studies show them grouping with snakes and other limbless squamates (e.g., Rage 1982;Estes et al. 1988;Conrad 2008;Gauthier et al. 2012). However, recent molecular analyses using DNA sequencing suggest that amphisbaenians is the sister group to Lacertidae (e.g., Townsend et al. 2004;Vidal and Hedges 2005;Pyron et al. 2013;Reeder et al. 2015;Zheng and Wiens 2016;Burbrink et al. 2020). ...
We studied at least part of Kuhnʼs original material of lizards from the Paleocene (~MP 5) of the Walbeck locality in Germany. The collection was considered to be lost but is consistently discussed in the literature due to its importance. We restudied the type material of aff. Parasauromalus paleocenicus and aff. Glyptosaurus walbeckensis described by Kuhn in 1940. The former was originally allocated to Iguania, the latter to Anguimorpha, though later on these identifications were questioned by several authors. We show such a classification of both cannot be upheld. P. paleocenicus resembles the morphology of lacertids showing their presence in Europe already around MP 5. We consider the name P. paleocenicus as a nomen dubium. The material of aff. G. walbeckensis was later suggested to belong to Lacertidae and also considered as a potential amphisbaenian. Although it differs from modern amphisbaenians, it shares features with one supposed polyodontobaenid – Camptognathosaurus parisiensis . The Walbeck form is identical to this species. Since the Walbeck taxon was described in 1940, the principle of priority makes Camptognathosaurus parisiensis a junior synonym of the species erected by Kuhn. We propose a new combined name for this form, Camptognathosaurus walbeckensis comb. nov. The specimen figured by Kuhn is currently lost, thus we designate a neotype from Walbeck. However, this taxon differs significantly from Polyodontobaena and new data doubt the attribution of Camptognathosaurus to Amphisbaenia. This taxon is tentatively assigned here to Lacertidae, as further confirmed by phylogenetic analyses. Material of Scincoidea is also described.
... Aff. Glyptosaurus walbeckensis lacks the following derived characters of Anguioidea (Estes et al. 1988;Gauthier et al. 2012): the splenial anterior inferior alveolar foramen is located between the splenial and the dentary (usually marked by the splenial spine) and the Meckelian canal opens ventrally in the anterior region (not medially for most of length). Moreover, the sulcus dentalis is present, whereas in anguimorphs, the dental crest is shallow and extends medioventrally. ...
... The specimen MLU.GeoS.4059 represents a lacertid since it exhibits the synapomorphies of the family (Estes et al. 1988;Gauthier et al. 2012), such as sulcus dentalis and lateral overlap of the posterodorsal margin of the dentary by the coronoid. The tooth morphology also indicates a lacertid rather than other groups: presence of bicuspid teeth, weak striations and sometimes a weakly-developed lingual cusp is common among members of Lacertidae, including Lacerta (see Kosma 2004;Čerňanský and Syromyatnikova 2019). ...
... In our analysis, in any case, this Paleocene taxon was never recovered as an amphisbaenian. According to morphological data, many studies show them grouping with snakes and other limbless squamates (e.g., Rage 1982;Estes et al. 1988;Conrad 2008;Gauthier et al. 2012). However, recent molecular analyses using DNA sequencing suggest that amphisbaenians is the sister group to Lacertidae (e.g., Townsend et al. 2004;Vidal and Hedges 2005;Pyron et al. 2013;Reeder et al. 2015;Zheng and Wiens 2016;Burbrink et al. 2020). ...
We studied at least part of Kuhnʼs original material of lizards from the Paleocene (~MP 5) of the Walbeck locality in Germany. The collection was considered to be lost but is consistently discussed in the literature due to its importance. We restudied the type material of aff. Parasauromalus paleocenicus and aff. Glyptosaurus walbeckensis described by Kuhn in 1940. The former was originally allocated to Iguania, the latter to Anguimorpha, though later on these identifications were questioned by several authors. We show such a classification of both cannot be upheld. P. paleocenicus resembles the morphology of lacertids showing their presence in Europe already around MP 5. We consider the name P. paleocenicus as a nomen dubium. The material of aff. G. walbeckensis was later suggested to belong to Lacertidae and also considered as a potential amphisbaenian. Although it differs from modern amphis-baenians, it shares features with one supposed polyodontobaenid-Camptognathosaurus parisiensis. The Walbeck form is identical to this species. Since the Walbeck taxon was described in 1940, the principle of priority makes Camptognathosaurus parisiensis a junior synonym of the species erected by Kuhn. We propose a new combined name for this form, Camptognathosaurus walbeck-ensis comb. nov. The specimen figured by Kuhn is currently lost, thus we designate a neotype from Walbeck. However, this taxon differs significantly from Polyodontobaena and new data doubt the attribution of Camptognathosaurus to Amphisbaenia. This taxon is tentatively assigned here to Lacertidae, as further confirmed by phylogenetic analyses. Material of Scincoidea is also described.
... Molecular analyses have yet to convincingly resolve relationships among gekkotans, dibamids and unidentatans (all other lizards) that they place at the base of Squamata [2,6]. By contrast, morphological trees [3,7] firmly root between Iguania and the rest of squamates (Scleroglossa), including gekkotans, which are the next crown divergence among scleroglossans. To further complicate matters, molecular analyses never find Iguania as sister to the rest of crown squamates [2]. ...
... These include the fusion of the frontals observed in Gekkota (except in the sphaerodactylid Teratoscincus), with paired frontals being retained in most stem gekkotans (including †Helioscopus dickersonae; figure 3c), but with fusion occurring in some stem species such as †Schoenesmahl dyspepsia [27] and †Hoburogekko suchanovi [29]. An absence of pterygoid dentition (indicating an edentulous palate) is shared between the gekkotan crown [7] and †H. dickersonae. ...
Geckos are a speciose and globally distributed clade of Squamata (lizards, including snakes and amphisbaenians) that are characterized by a host of modifications for nocturnal, scansorial and insectivorous ecologies. They are among the oldest divergences in the lizard crown, so understanding the origin of geckoes (Gekkota) is essential to understanding the origin of Squamata, the most species-rich extant tetrapod clade. However, the poor fossil record of gekkotans has obscured the sequence and timing of the assembly of their distinctive morphology. Here, we describe the first North American stem gekkotan based on a three-dimensionally preserved skull from the Morrison Formation of western North America. Despite its Late Jurassic age, the new species already possesses several key characteristics of the gekkotan skull along with retained ancestral features. We show that this new stem gekkotan, and several previously named species of uncertain phylogenetic relationships, comprise a widespread clade of early crown lizards, substantiating faunal homogeneity in Laurasia during the Late Jurassic that extended across disparate ecological, body-size and physiological classes.
... Among all known vertebrate hosts parasitized by ticks, animals classified within Reptilia have been the least studied. Traditional "Reptiles" include five extant paraphyletic clades, Squamata (e.g., lizards and snakes), Sphenodontia (Tuatara), Testudines (e.g., turtles), Aves, and Crocodilia (alligators and crocodiles) (Doneley, 2017;Estes et al., 1988;Ruta et al., 2003) (Figure 2). Ticks are broadly classified into two families, hard ticks (Ixodidae) known for harboring and transmitting a diverse array of human pathogens including Lyme borreliae, and soft ticks (Argasidae), recognized as the first ticks to vector a distinct lineage of Borrelia causing tick-borne relapsing fever (TBRF), or Relapsing Fever Borreliosis (Barbour & Gupta, 2021; F I G U R E 1 Host dilution and amplification effects on B. burgdorferi s.l. ...
Emerging and re‐emerging pathogens often stem from zoonotic origins, cycling between humans and animals, and are frequently vectored and maintained by hematophagous arthropod vectors. The efficiency by which these disease agents are successfully transmitted between vertebrate hosts is influenced by many factors, including the host on which a vector feeds. The Lyme disease bacterium Borrelia burgdorferi sensu lato has adapted to survive in complex host environments, vectored by Ixodes ticks, and maintained in multiple vertebrate hosts. The versatility of Lyme borreliae in disparate host milieus is a compelling platform to investigate mechanisms dictating pathogen transmission through complex networks of vertebrates and ticks. Squamata, one of the most diverse clade of extant reptiles, is comprised primarily of lizards, many of which are readily fed upon by Ixodes ticks. Yet, lizards are one of the least studied taxa at risk of contributing to the transmission and life cycle maintenance of Lyme borreliae. In this review, we summarize the current evidence, spanning from field surveillance to laboratory infection studies, supporting their contributions to Lyme borreliae circulation. We also summarize the current understanding of divergent lizard immune responses that may explain the underlying molecular mechanisms to confer Lyme spirochete survival in vertebrate hosts. This review offers a critical perspective on potential enzootic cycles existing between lizard‐tick‐Borrelia interactions and highlights the importance of an eco‐immunology lens for zoonotic pathogen transmission studies.
... The ventral surface has a longitudinal furrow, which probably increased in size towards caudal. The best preserved anterior caudal was mistaken with a pygal vertebra of a mosasaur (Arbour and Currie, 2016), however the articular face is not procoelic like in these squamates (Estes et al., 1988). Only one neural peduncle is preserved, but incomplete. ...
The first dinosaur discovered in the Antarctic continent was the ankylosaur Antarctopelta oliveroi in the 1980s.
Nevertheless, since then several hypotheses of phylogenetical relationships have been proposed because these have been
depended on how the skeletal remains have been interpreted. The main obstacle for clarifying its phylogenetic position is that
many portions of the skeleton remain unknown, in addition to the presence of unknown characters in typical ankylosaurs.
Considered an ankylosaurid, nodosaurid, or even a chimaera, a recent proposal based on mostly complete material of a new
ankylosaur from Chilean Patagonia provided support for a novel phylogenetic hypothesis: Antarctopelta and other southern
ankylosaurs are an early branching clade, the Parankylosauria, whose origin probably dates to the Late Jurassic. In the light of
this new view, a redescription of the available skeletal remains is provided together with a new reconstruction of the first
Antarctic dinosaur known to the science community.
... Its enlargement resulted in the loss of many other dermic bones. Skull characters are so important to snakes that the taxon is diagnosticated based in some features, as the absence of the lacrimal, squamosal, and epipterygoid bones (Estes et al. 1988) and the absence of bony mandibular symphysis and contact between frontal and maxilla bones (Conrad 2008) (Fig. 7). ...
Based on high-resolution computed tomography scanning, we provide new insights into the inner ear and stapedial morphology of Morganucodon from the Early Jurassic of St Brides. At the base of mammaliaforms, Morganucodon plays a pivotal role in understanding the sequence of character acquisition from basal cynodonts to mammals, including the detachment of the middle ear and the evolution of high-frequency hearing. Advancements in imaging technology enabled us to revise or newly describe crucial anatomy that was not accessible for the original description of Morganucodon. Based on 37 petrosals, we can confirm that the apex of the cochlear canal is expanded in Morganucodon, suggestive of a lagena macula. A gently raised crest along the abneural margin is reminiscent of (although much shallower than) the secondary lamina base of other Mesozoic mammaliaforms. The venous circum-promontorial plexus, which surrounded the inner ear in several basal mammaliaforms, was connected to the cochlear labyrinth in Morganucodon through numerous openings along the secondary lamina base. Two petrosals contain fragmentary stapes, which differ substantially from previously described isolated stapes attributed to Morganucodon in having peripherally placed crura and an oval and bullate footplate. Based on the revised stapedial morphology, we question the traditional view of an asymmetrical bicrural stapes as the plesiomorphic condition for Mammaliaformes.
Although many early anatomical papers touched on lizard ears, the absence of accurate tools severely limited progress. After 1950, new techniques permitted detailed anatomical descriptions and revealed the remarkable variations between the auditory papillae of different lizard families and a recognition of their usefulness of the variations for systematics. From the late 1960s, much new anatomical and physiological work ensued from a number of labs, including recordings from the auditory nerve. Cochlear microphonic recordings were initially dominant, but lost significance due to their poor interpretability. The various studies led to a new understanding of the relationships between structure and function and of the evolutionary and functional significances of the large differences between lizard families. The structural characteristics of lizard papillae enabled modeling of how hair cells couple to produce both sensitive- and frequency-selective responses in the auditory nerve. They also permitted a localization of the active process of lizard ears to the hair cell bundle.
Myrmecophagy is one of the most common dietary specializations among vertebrates. Ants are an important food resource for many lizard species. Here, we use a large dataset on ant consumption by lizards (345 species, 33 families) to explore evolutionary and ecological correlates of myrmecophagy across the evolutionary history of lizards. Based on literature and previous empirical work, we develop and test the following hypotheses about myrmecophagy: (i) it does not occur randomly across Squamata; it is correlated with (ii) foraging mode, (iii) habitat, (iv) body size, (v) aridity, and/or (vi) species range size. We found that ant ingestion is not distributed randomly in the phylogeny, with higher ingestion concentrated in some Iguania. Myrmecophagy also evolved in Lacertoidea and it is a derived trait with relatively recent origin. Foraging mode, habitat, body size, and aridity do not influence ant ingestion. Species with smaller range sizes show high variability in ant ingestion, whereas lizards with larger ranges tend to eat a lower proportion of ants. This result confirms the general ecological pattern that specialization is more common in narrowly distributed species. We suggest that future studies should also explore dietary specialization more broadly and provide a better taxonomic resolution of ant species in the diet of lizards.
French zoologist and naturalist Georges Cuvier (1769–1832), one of the most eminent scientific figures of the early nineteenth century, is best known for laying the foundations of comparative anatomy and palaeontology. He spent his lifetime studying the anatomy of animals, and broke new ground by comparing living and fossil specimens - many he uncovered himself. However, Cuvier always opposed evolutionary theories and was during his day the foremost proponent of catastrophism, a doctrine contending that geological changes were caused by sudden cataclysms. He received universal acclaim when he published his monumental Le règne animal, which made significant advances over the Linnaean taxonomic system of classification and arranged animals into four large groups. The sixteen-volume English translation and expansion, The Animal Kingdom (1827–35), is also reissued in the Cambridge Library Collection. First published in 1817, Volume 1 of the original version covers mammals and birds.