The Fragmentation of Gondwanaland: Influence on the Historical Biogeography and Morphological Evolution within Dragon Lizards (Squamata: Agamidae)

Following the break up of the Pangaea, landmasses were aggregated into two super-continents, Laurasia in the northern hemisphere and Gondwanaland in the southern hemisphere. Both have been considered ancestral areas where many of today’s taxonomic groups originated. However, during the Devonian, Gondwanaland began to fragment with micro-continental blocks breaking and rafting northwestwards across the Tethys Sea. These micro-continents eventually collided into Laurasia transforming into what today is Southeast Asia and parts of Wallacea. These micro-continental blocks carried Gondwanan lineages that evolved in isolation as they rafted across the Tethys Sea and subsequently dispersed into Laurasia. This geologic scenario has been used to explain why there are Asian lineages of lizards, birds, fish, and land snails that are more closely related to Australian and Papuan taxa than they are to other Asian lineages. One well-documented case of this biogeographic hypothesis is with Dragon Lizards. There have been two previous comprehensive studies on Dragon Lizard relationships, one based on discrete morphological characters and one using molecular data, and both predicted Gondwanan origins for all Dragon Lizards commensurate with the geologic scenario outlined above. Both studies, however, were based on limited sampling and reported problematic relationships that hindered their ability to unequivocally explain the geographic and evolutionary origins of this lizard family. In this dissertation, I use phylogenomic data to resolve long-standing contentious Dragon Lizard relationships in order to revisit hypotheses of their Gondwanan origins and Tethys Sea migrations. I first use this phylogeny to test the hypothesis of an Indian (Gondwanan) origin for Southeast Asian Dragon Lizards and reevaluate the colonization of the Indian and the Indo-Himalaya regions. Once these problematic relationships and biogeographic origins were resolved, it enabled me to use unprecedented taxonomic sampling to provide the first estimate of a Dragon Lizard tree of life in order to test previous published hypotheses of Gondwanan origins and the morphological evolution within Dragon Lizards. Lastly, I use a dataset of 122 discrete morphological characters from a previous study and sum the number of unambiguous synapomorphies in the cranial and post-cranial skeletal characters associated with cephalic and axial body modifications in lineages that have morphological specializations in these regions. Lastly, I use the Dragon Lizard Tree of Life and these synapomorphies to perform a phylogenetic logistic regression analysis to show that the evolution of the higher number of relative synapomorphies associated with cephalic and axial body modifications are phylogenetically independent of one another. This study contributes to our knowledge of Gondwanan and Laurasian biogeography as well as how shared environmental pressures affect the external and internal morphology of unrelated species within Dragon lizards

Another new species of Dixonius (Squamata, Gekkonidae) from Gia Lai Province in the Central Highlands, Vietnam

Another new species of Dixonius, D. fulbrighti sp. nov., is described from Gia Lai Province, in the Central Highlands of Vietnam, using an integrated approach based on morphological, categorical (color pattern), and mitochondrial NADH dehydrogenase subunit 2 gene (ND2) and its flanking tRNAs data. Phylogenetic analyses recovered Dixonius fulbrighti sp. nov. as closely related to D. gialaiensis from Gia Lai Province and part of a clade that includes D. minhlei, D. siamensis, and D. somchanhae. Multivariate (PCA, DAPC, and MFA) and univariate (ANOVA) analyses of 15 meristic (scale counts), six morphometric (mensural), and five categorical (color pattern and morphology) characters from 44 specimens of all eight species of Dixonius from Vietnam, Laos, and Cambodia clearly demonstrated that Dixonius fulbrighti sp. nov. is statistically different and diagnostically distinct from all closely related species of Dixonius. This new species discovery highlights the underestimated gecko diversity and the importance of continued fieldwork in the Central Highlands of Vietnam

The biogeography of bent-toed geckos, Cyrtodactylus (Squamata: Gekkonidae)

The gekkonid genus Cyrtodactylus is the third largest vertebrate genus on the planet with well over 300 species that range across at least eight biogeographic regions from South Asia to Melanesia. The ecological and morphological plasticity within the genus, has contributed to its ability to disperse across ephemeral seaways, river systems, basins, land bridges, and mountain ranges—followed by in situ diversification within specific geographic areas. Ancestral ranges were reconstructed on a mitochondrial phylogeny with 346 described and undescribed species from which it was inferred that Cyrtodactylus evolved in a proto-Himalaya region during the early Eocene. From there, it dispersed to what is currently Indoburma and Indochina during the mid-Eocene— the latter becoming the first major center of origin for the remainder of the genus that seeded dispersals to the Indian subcontinent, Papua, and Sundaland. Sundaland became a second major center of radiation during the Oligocene and gave rise to a large number of species that radiated further within Sundaland and dispersed to Wallacea, the Philippines, and back to Indochina. One Papuan lineage dispersed west to recolonize and radiate in Sundaland. Currently, Indochina and Sundaland still harbor the vast majority of species of Cyrtodactylus

The Eurasian invasion: phylogenomic data reveal multiple Southeast Asian origins for Indian Dragon Lizards

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Background: The Indian Tectonic Plate split from Gondwanaland approximately 120 MYA and set the Indian subcontinent on a ~ 100 million year collision course with Eurasia. Many phylogenetic studies have demonstrated the Indian subcontinent brought with it an array of endemic faunas that evolved in situ during its journey, suggesting this isolated subcontinent served as a source of biodiversity subsequent to its collision with Eurasia. However, recent molecular studies suggest that Eurasia may have served as the faunal source for some of India’s biodiversity, colonizing the subcontinent through land bridges between India and Eurasia during the early to middle Eocene (~35–40 MYA). In this study we investigate whether the Draconinae subfamily of the lizard family Agamidae is of Eurasian or Indian origin, using a multi locus Sanger dataset and a novel dataset of 4536 ultraconserved nuclear element loci. Results: Results from our phylogenetic and biogeographic analyses revealed support for two independent colonizations of India from Eurasian ancestors during the early to late Eocene prior to the subcontinent’s hard collision with Eurasia. Conclusion: These results are consistent with other faunal groups and new geologic models that suggest ephemeral Eocene land bridges may have allowed for dispersal and exchange of floras and faunas between India and Eurasia during the Eocene

Two new species of Dixonius from Vietnam and Laos with a discussion of the taxonomy of Dixonius (Squamata, Gekkonidae)

Integrated analyses using maximum likelihood (ML), Bayesian inference (BI), principal component analysis (PCA), discriminate analysis of principal components (DAPC), multiple factor analysis (MFA), and analysis of variance (ANOVA) recovered two new diagnosable species of gekkonid lizards in the genus Dixonius, one from the Central Highlands, Gia Lai Province, Vietnam and another from the Vientiane Province, Laos. Phylogenetic analyses based on the mitochondrial NADH dehydrogenase subunit 2 gene (ND2) and adjacent tRNAs showed that Dixonius gialaiensis sp. nov. is the sister species of D. minhlei from Dong Nai Province, Vietnam and is nested within a clade that also includes the sister species D. siamensis and D. somchanhae. Dixonius muangfuangensis sp. nov. is the sister species to D. lao from Khammouane Province, Laos and is embedded in a clade with D. vietnamensis, D. taoi, and undescribed species from Thailand. Multivariate (PCA, DAPC, and MFA) and univariate (ANOVA) analyses using combinations of 15 meristic (scale counts), six morphometric (measurements), and five categorical (color pattern and morphology) characters from 44 specimens encompassing all eight species of Dixonius from Vietnam and Laos clearly illustrate Dixonius gialaiensis sp. nov. and Dixonius muangfuangensis sp. nov. are statistically different and discretely diagnosable from all closely related species of Dixonius. These integrative analyses also highlight additional taxonomic issues that remain unresolved within Dixonius and the need for additional studies. The discovery of these new species further emphasizes the underappreciated herpetological diversity of the genus Dixonius and illustrates the continued need for field work in these regions

Phylogenetic and multivariate analyses of Gekko smithii Gray, 1842 recover a new species from Peninsular Malaysia and support the resurrection of G. albomaculatus (Giebel, 1861) from Sumatra

An integrative taxonomic analysis of Sundaic populations of Gekko smithii from the Thai-Malaya Peninsula, Sumatra, and Borneo recovered four deeply divergent mitochondrial lineages that are separated by major geographic barriers (mountains and seaways). Furthermore, they bear a number of concordant statistically significant differences in meristic and morphometric features, morphospatial separation in multivariate space, and discrete differences in color pattern. Gekko smithii sensu stricto is restricted to southern Thailand south of the Isthmus of Kra and Peninsular Malaysia west of the Banjaran (mountain range) Titiwangsa, being that the type locality is on Penang Island, Penang. Gekko hulk sp. nov. is a new species from extreme southern Thailand and Peninsular Malaysia east of the Banjaran Titiwangsa and five east coast islands—the type locality being Pulau (island) Tioman, Pahang. Gekko cf. albofasciolatus is tentatively used to include Bornean populations west of the Iran Mountains in Sabah and Sarawak which, in the absence of molecular data, cannot unequivocally be separated morphologically from G. albofasciolatus from the type locality at Banjarmasin, Kalimantan, Indonesia east of the Iran Mountains. In the absence of molecular data, G. albomaculatus is resurrected to include mainland Sumatran, Nias Island, and Banyak Islands populations which, based on their morphology, cannot be separated from descriptions of G. albomaculatus from the type locality of Bangka Island, 15 km off the southeast coast of mainland Sumatra. Further integrative analyses of all Sumatran and Bornean populations are currently underway as well as the enigmatic Wallacean populations from Sulawesi. Data are presented that strongly suggest all references to G. smithii from Java stem from a 151 year-old misidentification of a specimen of G. gecko of unknown provenance. Additionally, there are no vouchered records of G. smithii from Myanmar. The phylogeographic patterns of Sundaic populations of the G. smithii complex are concordant with those of a plethora of other Sundaic lineages

First report on the herpetofauna of Pulau Aur, Johor, West Malaysia

With the exception ofTweedie's (1983) account ofCalamaria lovii, published accounts on the herpetofauna of Pulau Aur, located 63 km off the south-east coast of peninsular Malaysia in the South China Sea did not exist prior to this report. The only species known from the island were based on the museum records ofLimnonectes blythii, Mabuya multi/asciata, Bronchocela cristatella, Gehyra mutilata, Varanus nebulosus and Ahaetulla prasina deposited in the Raffles Museum of Biodiversity Research. A short expedition to the island on 15-16 July 2001 yielded an additional 12 species, comprising 10 lizards and two snakes: Limnonectes blythii; Bronchocela cristatella; Cnemaspis cf. Nigridia; Cosymbotus platyurus; Cyrtodactylus consobrinus; Gehyra mutilata; Gekko monarchus; Hemidactylus frenatus; Dasia o/ivacea; Emoia atrocostata; Lygosoma bowring;;; Mabuya multi/asciata; Sphenomorphus scotophi/us; Varanus nebulosus; Varanus salvator; Ramphotyphlops cf. braminus; Calamaria lovii and Macropisthodon flaviceps