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Thomas Wilms - One of the best experts on this subject based on the ideXlab platform.
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Evolutionary history of spiny-tailed lizards (Agamidae: Uromastyx) from the Saharo-Arabian region
Zoologica Scripta, 2018Co-Authors: Karin Tamar, Thomas Wilms, Andreas Schmitz, Margarita Metallinou, Pierre-andré Crochet, Philippe Geniez, Salvador CarranzaAbstract:The subfamily Uromastycinae within the Agamidae is comprised of 18 species: three within the genus Saara and 15 within Uromastyx. Uromastyx is distributed in the desert areas of North Africa and across the Arabian Peninsula towards Iran. The systematics of this genus has been previously revised, although incomplete taxonomic sampling or weakly supported topologies resulted in inconclusive relationships. Biogeographic assessments of Uromastycinae mostly agree on the direction of dispersal from Asia to Africa, although the timeframe of the cladogenesis events has never been fully explored. In this study, we analysed 129 Uromastyx specimens from across the entire distribution range of the genus. We included all but one of the recognized taxa of the genus and sequenced them for three mitochondrial and three nuclear markers. This enabled us to obtain a comprehensive multilocus time‐calibrated phylogeny of the genus, using the concatenated data and species trees. We also applied coalescent‐based species delimitation methods, phylogenetic network analyses and model‐testing approaches to biogeographic inferences. Our results revealed Uromastyx as a monophyletic genus comprised of five groups and 14 independently evolving lineages, corresponding to the 14 currently recognized species sampled. The onset of Uromastyx diversification is estimated to have occurred in south‐west Asia during the Middle Miocene with a later radiation in North Africa. During its Saharo‐Arabian colonization, Uromastyx underwent multiple vicariance and dispersal events, hypothesized to be derived from tectonic movements and habitat fragmentation due to the active continental separation of Arabia from Africa and the expansion and contraction of arid areas in the region.
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On the distribution of Uromastyx alfredschmidti Wilms and Böhme, 2000 (Squamata: Agamidae: Uromastycinae)
Acta Herpetologica, 2012Co-Authors: Roberto Sindaco, Thomas Wilms, Alberto VenchiAbstract:The article reports on two new findings of Uromastyx alfredschmidti Wilms and Bohme, 2000 that allow for a more precise definition of its distribution range and, consequently, a new conservation assessment in compliance with IUCN parameters. Following review of available museum specimens, the Hoggar Mts. (Algeria), should not to be considered within the natural range of the species. Nomenclatorial clarifica- tions on existing literature are also provided.
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Mitochondrial DNA Variability within Uromastyx ornata philbyi (Agamidae: Squamata) from Southwestern Saudi Arabia.
Comparative and functional genomics, 2012Co-Authors: Sayed A. M. Amer, Mohammed Shobrak, Thomas Wilms, Mohamed Ahmed, Yoshinori KumazawaAbstract:Approximately 2.4 kbp of mitochondrial DNA was sequenced from 9 individuals of Uromastyx ornata philbyi originating from Taif, Namas, Al-Baha, and Jazan in southwestern Saudi Arabia. The sequenced regions cover eight tRNA genes (, , , , , , , and ) and two protein-coding genes (NADH dehydrogenase subunit 2 and cytochrome b). U. ornata philbyi had an insertion of 170 bp length between and genes. The first 128 bp of this insertion was similar to the one identified earlier in U. ornata ornata and can be folded into a stem-and-loop structure, which was less stable in U. ornata philbyi than in U. ornata ornata, or the second gene. The next 42 bp of the insertion was unique in U. ornata philbyi and additionally retained a stable stem-and-loop structure. Most base substitutions found in the sequenced genes were synonymous transitions rather than transversions. Tree analyses supported the sister group relationship between the two U. ornata subspecies and divided U. ornata philbyi into two groups: Taif
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On the Phylogeny and Taxonomy of the Genus Uromastyx Merrem, 1820 (Reptilia: Squamata: Agamidae: Uromastycinae) - Resurrection of the Genus Saara Gray, 1845
2009Co-Authors: Thomas Wilms, Wolfgang Böhme, Philipp Wagner, Andreas Schmitz, Zoologisches Forschungsmuseum, Alexander KoenigAbstract:We assessed the taxonomic relationships within the genus Uromastyx Merrem, 1820 using morphologi- cal and genetic methods, resulting in the resurrection of the genus Saara Gray, 1845 for Saara hardwickii, S. as- mussi and S. loricata and in changes of the taxonomic rank of Uromastyx nigriventris, U. aegyptia leptieni and U. shobraki. A synopsis of all taxa considered to be valid is provided, including differential diagnosis, description and data on their respective distribution. A key for the species of Saara and Uromastyx is presented.
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A new polytypic species of the genus Uromastyx M ERREM 1820 (Reptilia: Squamata: Agamidae: Leiolepidinae) from southwestern Arabia
Zootaxa, 2007Co-Authors: Thomas Wilms, Andreas SchmitzAbstract:We describe Uromastyx yemenensis sp. nov. from south-western Arabia, comprising two geographic subspecies, U. y. yemenensis and U. y. shobraki ssp. nov. The new species is a member of the Uromastyx ocellata species group, closely related to U. benti. It is differentiated from its sister taxon by smaller scales around midbody and smaller ventrals. The new species is restricted to the extreme south-western tip of the Arabian Peninsula. The western populations of U. yemenensis differ genetically and are constantly distinct in respect to their colour pattern and are therefore recognized as a subspecies.
Michael J. Fagan - One of the best experts on this subject based on the ideXlab platform.
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Biomechanical assessment of evolutionary changes in the lepidosaurian skull
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Mehran Moazen, Susan E. Evans, Neil Curtis, Paul O'higgins, Michael J. FaganAbstract:The lepidosaurian skull has long been of interest to functional morphologists and evolutionary biologists. Patterns of bone loss and gain, particularly in relation to bars and fenestrae, have led to a variety of hypotheses concerning skull use and kinesis. Of these, one of the most enduring relates to the absence of the lower temporal bar in squamates and the acquisition of streptostyly. We performed a series of computer modeling studies on the skull of Uromastyx hardwickii, an akinetic herbivorous lizard. Multibody dynamic analysis (MDA) was conducted to predict the forces acting on the skull, and the results were transferred to a finite element analysis (FEA) to estimate the pattern of stress distribution. In the FEA, we applied the MDA result to a series of models based on the Uromastyx skull to represent different skull configurations within past and present members of the Lepidosauria. In this comparative study, we found that streptostyly can reduce the joint forces acting on the skull, but loss of the bony attachment between the quadrate and pterygoid decreases skull robusticity. Development of a lower temporal bar apparently provided additional support for an immobile quadrate that could become highly stressed during forceful biting.
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Assessment of the role of sutures in a lizard skull: A computer modelling study
Proceedings of The Royal Society B: Biological Sciences, 2008Co-Authors: Mehran Moazen, Marc E H Jones, Neil Curtis, Susan E. Evans, Paul O'higgins, Michael J. FaganAbstract:Sutures form an integral part of the functioning skull, but their role has long been debated among vertebrate morphologists and palaeontologists. Furthermore, the relationship between typical skull sutures, and those involved in cranial kinesis, is poorly understood. In a series of computational modelling studies, complex loading conditions obtained through multibody dynamics analysis were imposed on a finite element model of the skull of Uromastyx hardwickii, an akinetic herbivorous lizard. A finite element analysis (FEA) of a skull with no sutures revealed higher patterns of strain in regions where cranial sutures are located in the skull. From these findings, FEAs were performed on skulls with sutures (individual and groups of sutures) to investigate their role and function more thoroughly. Our results showed that individual sutures relieved strain locally, but only at the expense of elevated strain in other regions of the skull. These findings provide an insight into the behaviour of sutures and show how they are adapted to work together to distribute strain around the skull. Premature fusion of one suture could therefore lead to increased abnormal loading on other regions of the skull causing irregular bone growth and deformities. This detailed investigation also revealed that the frontal–parietal suture of the Uromastyx skull played a substantial role in relieving strain compared with the other sutures. This raises questions about the original role of mesokinesis in squamate evolution.
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Rigid-body analysis of a lizard skull: modelling the skull of Uromastyx hardwickii.
Journal of biomechanics, 2008Co-Authors: Mehran Moazen, Susan E. Evans, Neil Curtis, Paul O'higgins, Michael J. FaganAbstract:Lizard skulls vary greatly in their detailed morphology. Theoretical models and practical studies have posited a definite relationship between skull morphology and bite performance, but this can be difficult to demonstrate in vivo. Computer modelling provides an alternative approach, as long as hard and soft tissue components can be integrated and the model can be validated. An anatomically accurate three-dimensional computer model of an Uromastyx hardwickii skull was developed for rigid-body dynamic analysis. The Uromastyx jaw was first opened under motion control, and then muscle forces were applied to produce biting simulations where bite forces and joint forces were calculated. Bite forces comparable to those reported in the literature were predicted, and detailed muscular force information was produced along with additional information on the stabilizing role of temporal ligaments in late jaw closing.
Wolfgang Böhme - One of the best experts on this subject based on the ideXlab platform.
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On the Phylogeny and Taxonomy of the Genus Uromastyx Merrem, 1820 (Reptilia: Squamata: Agamidae: Uromastycinae) - Resurrection of the Genus Saara Gray, 1845
2009Co-Authors: Thomas Wilms, Wolfgang Böhme, Philipp Wagner, Andreas Schmitz, Zoologisches Forschungsmuseum, Alexander KoenigAbstract:We assessed the taxonomic relationships within the genus Uromastyx Merrem, 1820 using morphologi- cal and genetic methods, resulting in the resurrection of the genus Saara Gray, 1845 for Saara hardwickii, S. as- mussi and S. loricata and in changes of the taxonomic rank of Uromastyx nigriventris, U. aegyptia leptieni and U. shobraki. A synopsis of all taxa considered to be valid is provided, including differential diagnosis, description and data on their respective distribution. A key for the species of Saara and Uromastyx is presented.
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Review of the taxonomy of the spiny-tailed lizards of Arabia (Reptilia: Agamidae: Leiolepidinae: Uromastyx)
2007Co-Authors: Thomas Wilms, Wolfgang BöhmeAbstract:A b s t r a c t : Currently six species of the genus Uromastyx (Reptilia: Agamidae: Leiolepidinae), representing three phylogenetic lineages, are known to occur in Arabia: Uromastyx aegyptia, U. benti, U. leptieni, U. ornata, U. thomasi and U. yemenensis. The present paper gives an overview of the taxonomy of these lizards and presents new data on the morphology and ecology of Uromastyx leptieni.
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A new Uromastyx species from south-eastern Arabia, with comments on the taxonomy of Uromastyx aegyptia (FORSKAL, 1775) (Squamata: Sauria: Agamidae) Eine neue Uromastyx - Art aus dem südöstlichen Arabien, mit Kommentaren zur Taxonomie von Uromastyx ae
2000Co-Authors: Thomas Wilms, Wolfgang BöhmeAbstract:KURZFASSUNG Es wird ein Oberblick uber die taxonomischen Verhaltnisse innerhalb der Uromastyx aegyptia - Gruppe gegeben, insbesondere wird der taxonomische Rang der Taxa aegyptia und microlepis diskutiert Es werden ein Neotypus fur aegyptia und ein Lectotypus fur microlepis designiert Uromastyx leptieni sp. n. wird aus dem sudostlichen Arabien beschrieben. Die neue Art unterscheidet sich von ihrem Schwestertaxon U. aegyptia durch grosere Ventralia und durch eine abweichende Farbung und Zeichnung der Jungtiere. Uromastyx leptieni sp. n. ist im nordlichen Oman und im Osten der Vereinigten Arabischen Emirate beheimatet.
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Zur Taxonomie und Verbreitung der Arten der Uromastyx-ocellata-Gruppe (Sauria: Agamidae)
Zoology in the Middle East, 2000Co-Authors: Von Thomas Wilms, Wolfgang BöhmeAbstract:Abstract An overview of the taxonomy of the ocellata group (benti, macfadyeni, ocellata, ornata, philbyi) is given and information on their distribution is provided. We distinguish five taxa within the ocellata group which are assigned to four species: Uromastyx benti, U. macfadyeni, U. ocellata and U. ornata. A lectotype of benti is designated and the type locality of Uromastyx ocellata is restricted to Suakin (north-eastern Sudan). Furthermore, a redescription of the holotype of macfadyeni is given and the specimen is figured. A key to the species of the ocellata group is provided.
I. Choshniak - One of the best experts on this subject based on the ideXlab platform.
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Microbial digestion in the herbivorous lizard Uromastyx aegyptius (Agamidae)
Journal of Zoology, 1992Co-Authors: William J. Foley, Amos Bouskila, A. Shkolnik, I. ChoshniakAbstract:The utilization of a diet rich in plant cell walls was studied in a large, desert-dwelling, herbivorous lizard, Uromastyx aegyptius (Agamidae). The diet eaten by U. aegyptius in spring in the ‘Arava Valley, Israel, consisted almost entirely of leaves and fruits of short-lived annual plant species. The leaves contained only moderate levels of fibre compared with grasses and tree leaves, but those fruits eaten were markedly higher in fibre and lignin. All items had notably high contents of ash. Following oral doses of [14C] cellulose, 14CO2 was detected in respired air from U. aegyptius, demonstrating that the cellulose was digested and that the lizards gained oxidative energy from cellulose degradation. The hind gut was the principal site of microbial activity and the apparent digestibility of the cell-wall fraction was 69%. Similarly, the caecum/proximal colon had the highest concentrations of SCFA (76–120 mM). The mean rate of SCFA production at 40 C in vitro was 31 mmol/1 h-1. Assuming that this is representative of daily production rate, 69 kJ/kg d-1 would be made available to the animal. This is 47% of the mean digestible energy intake estimated in free-living animals. Microbial fermentation contributes an important part of the energy budget of U. aegyptius but the effects of variation in body temperature on digestion and fermentation need further consideration.
Yoshinori Kumazawa - One of the best experts on this subject based on the ideXlab platform.
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Mitochondrial DNA Variability within Uromastyx ornata philbyi (Agamidae: Squamata) from Southwestern Saudi Arabia.
Comparative and functional genomics, 2012Co-Authors: Sayed A. M. Amer, Mohammed Shobrak, Thomas Wilms, Mohamed Ahmed, Yoshinori KumazawaAbstract:Approximately 2.4 kbp of mitochondrial DNA was sequenced from 9 individuals of Uromastyx ornata philbyi originating from Taif, Namas, Al-Baha, and Jazan in southwestern Saudi Arabia. The sequenced regions cover eight tRNA genes (, , , , , , , and ) and two protein-coding genes (NADH dehydrogenase subunit 2 and cytochrome b). U. ornata philbyi had an insertion of 170 bp length between and genes. The first 128 bp of this insertion was similar to the one identified earlier in U. ornata ornata and can be folded into a stem-and-loop structure, which was less stable in U. ornata philbyi than in U. ornata ornata, or the second gene. The next 42 bp of the insertion was unique in U. ornata philbyi and additionally retained a stable stem-and-loop structure. Most base substitutions found in the sequenced genes were synonymous transitions rather than transversions. Tree analyses supported the sister group relationship between the two U. ornata subspecies and divided U. ornata philbyi into two groups: Taif
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MOLECULAR AFFINITY OF SOMALI AND EGYPTIAN MASTIGURES AMONG THE AFRO-ARABIAN Uromastyx -
THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY, 2009Co-Authors: Sayed A. M. Amer, Yoshinori KumazawaAbstract:Mitochondrial DNA of approximately 1040 bp from 16S rRNA and cytochrome b genes were amplified and sequenced from 11 taxa belonging to 9 Uromastyx species. These species were U. hardwickii from India, U. macfadyeni from Somali, U. dispar from Sudan, U. acanthinura from Morocco, U. geyri from Mali, U. aegyptia from Egypt and Arabia, U. benti from Yemen, U. ocellata from Egypt and Sudan and U. ornata from Sinai and Arabia. Nucleotides from these genes were used in combination with 1700 aligned sites from the mitochondrial DNA segment located between NADH dehydrogenase subunit 1 (ND1) to cytochrome oxidase subunit 1 (CO1) genes -that was previously sequenced for the same taxa to- test the phylogenetic position of U. aegyptia and U. macfadyeni. Different tree building methods were used and only single tree was given in which the positions of both Uromastyx taxa were identical to those produced by the previous molecular data but with stronger statistical supports. U. aegyptia was clustered within the Arabian clade and U. macfadyeni was clustered within the African clade.
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Mitochondrial DNA sequences of the Afro-Arabian spiny-tailed lizards (genus Uromastyx; family Agamidae) : phylogenetic analyses and evolution of gene arrangements
Biological Journal of the Linnean Society, 2005Co-Authors: Sayed A. M. Amer, Yoshinori KumazawaAbstract:Approximately 1.7 kbp of mitochondrial DNA were sequenced from 29 individuals assignable to 11 Uromastyx species or subspecies and two other agamids. U. ocellata and U. ornata had an insertion between the glutamine and isoleucine tRNA genes, which could be folded into a stable stem-and-loop structure, and the insertion for U. ornata additionally retained a sequence similar to the glutamine tRNA gene. This corroborates the role of tandem duplication in reshaping mitochondrial gene arrangements, and supports the idea that the origin of light-strand replication could be relocated within mitochondrial genomes. Molecular phylogeny from different tree-building methods consistently placed African and Arabian taxa in mutually monophyletic groups, excluding U. hardwickii inhabiting India and Pakistan. Unlike previous studies based on morphology, U. macfadyeni did not cluster with morphologically similar Arabian taxa, suggesting convergent evolution to be responsible for the morphological similarities. Divergence times estimated among the Uromastyx taxa, together with geological and palaeontological evidence, suggest that the Uromastyx agamids originated from Central Asia during the Eocene and colonized Africa after its connection with Eurasia in the early Miocene. Their radiation may have been facilitated by repeated aridification of North Africa since the middle Miocene, and geological events such as the expansion of the Red Sea and the East African Rift Valley.
