Session 19: ASIH Stoye General Herpetology IIRoom: Ballroom 111A2022-07-29 10:00 - 11:45 |
| Moderator: Brad Shaffer |
|
1. 10:00 Life History Differences Along the Fast-Slow Continuum in Introduced Lizards in Hawaii. Spencer Alascio*, University of Hawaii at Manoa; Jose Carranza, University of Hawaii at Manoa; Amber Wright, University of Hawaii at Manoa salascio@hawaii.edu
A species’ life history is the set of traits related to the timing and nature of events related to growth, reproduction, and survival. Life history traits often occur along a ‘fast’ vs. ‘slow’ continuum, and fast life histories are frequently associated with invasion success. We documented life history traits in introduced brown anole (Anolis sagrei), green anole (Anolis carolinensis) and gold dust day gecko (Phelsuma laticauda) lizards to determine whether species differences along the fast-slow axis can help explain community changes over time. Single species populations were established in replicate 10m x10m seminatural enclosures and censused weekly for one year to track growth and survival of colonists and their offspring. We fit capture-mark-recapture models and logistic-by-weight growth models to estimate population size, survival rate, and time to sexual maturity. Brown anoles females reached sexual maturity twice as fast as female green anoles and almost three times as fast as female day geckos. Male brown anoles had a monthly survival rate of 50%, the lowest survival rate compared to any other group regardless of species or sex with the next closest group averaging 82%. Brown anole populations achieved stable densities up to 3 times higher than the other species under the same resource availability. Our findings are consistent with community changes on Oahu; brown anoles are the most widespread and abundant of our three focal species, and this may be driven in part by the ability for both individuals and populations to grow quickly, and for populations to achieve high densities. |
|
2. 10:15 Urban Ecology of DeKay's Brown Snake, Storeria dekayi. Tianqi Huang*, Rutgers University-New Brunswick; Peter Morin, Rutgers University-New Brunswick; Sara Ruane, The Field Museum of Natural History th431@scarletmail.rutgers.edu
The process of urbanization has changed natural landscapes and threatened the survival of wildlife, which draws increasing attention to the conservation of urban biota. Currently, most work assessing the effect of urbanization on wildlife has been predominately focused on birds and arthropods, with few studies conducted on other taxa, such as the elusive reptiles. DeKay’s brown snake (Storeria dekayi) is a small, semi-fossorial snake species found throughout the Eastern and Central United States. They frequently inhabit urban areas and form aggregations, providing an opportunity to explore how reptiles respond to urban environments. Using a combination of occurrence records, museum specimens, and contemporary sampling of S. dekayi from sites with different urbanization levels in New Jersey, we 1) compared morphological traits between populations to test whether traits are influenced by urban environs, and 2) built ecological niche models of S. dekayi throughout North America to predict how different environmental variables affect distributions, and how future distributions would change with the anthropogenically influenced climate regimes. Initial results suggest that human disturbance contributes to current S. dekayi distributions and that the range size of S. dekayi would expand in the future. Head shape differs among S. dekayi from sites with different urbanization levels. Populations from some more urbanized sites exhibit less distinct sexual dimorphism. This work highlights the need to further explore lesser known yet potentially abundant urban species to understand what traits are influenced by urban environs and to maintain this component of urban biodiversity. |
|
3. 10:30 Ecological Opportunity Drives Morphological Evolution in the Ecologically Diverse Garter and Water Snakes (Thamnophiini). Leroy Núñez*, American Museum of Natural History; Frank Burbrink, American Museum of Natural History lnunez@amnh.org
North American Thamnophiini (gartersnakes, watersnakes, brownsnakes, and swampsnakes) are a clade of colubroid snakes that exhibits a high level of ecological variance and a wide variety of diet preferences inhabiting many disparate biomes. Additionally, Thamnophiini represents an asymmetric radiation where 57% of species diversity is represented by the garter snakes. Furthermore, the group is geographically unevenly distributed; Thamnophis is the only genus that naturally occurs west of the Western Continental Divide in North America. As a result, ecological specializations occur independently throughout the clade in both Eastern and Western taxa. However, it is unclear if this ecological convergence extends to deeper morphological traits. Using high-dimensional shape data collected from µCT-scans and a well-resolved phylogeny of Thamnophiini inferred from genomic data, we conducted geometric morphometrics to analyze the tempo and mode of trait evolution of the snake skull. Morphology of the snake skull has been shown to be influenced by natural history traits such as diet. Furthermore, we conducted Bayesian phylogenetic comparative methods that explicitly incorporate background rate heterogeneity across the tree to assess the impact of natural history traits, such as diet and microhabitat, and geography on morphological evolution. Our results support morphological convergence of skull shape across different ecotypes. Moreover, our results provide evidence that morphological rate is influenced by habitat and geography, with western taxa exhibiting higher rates of morphological evolution than eastern taxa. This suggests that Thamnophiini diversification is driven by ecological opportunity following the westward expansion of Thamnophis lineages. |
|
4. 10:45 Assessing Biogeographic Trends in Body Size of Gila Monsters Using Mechanistic and Correlative Models. Connor Hughes*, Center of Excellence for Field Biology, Austin Peay State University; Jason L. Jones, Wildlife Diversity Division, Nevada Department of Wildlife; C. M. Gienger, Center of Excellence for Field Biology, Austin Peay State University connorhughes926@gmail.com
Gila monsters are a large, cryptic, and long-lived lizard native to the desert southwest. Environmental conditions vary drastically across their range from the extreme northern Mojave to the extreme southern Sonoran Desert and Thornscrub. We collected over 800 measurements of body size from individuals across their range and clustered them into relevant geographically explicit populations. Using a combination of mechanistic microclimate and biophysical models, we generate a spatial matrix of predicted potential surface activity times across the species range based on the overall thermal constraints on this species. We then compared the mechanistically derived variable of potential activity time with several a priori correlative variables, each representing either existing hypotheses about biogeographical patterns in body size, or parameters that have been shown to significantly influence desert ectotherm growth rates. We compare each variable’s ability to explain body size trends across geographic units and use this to generate hypotheses related to the driving forces of variation in body size for this species. Results will be presented and discussed. |
|
5. 11:00 Systematics and Biogeography of Australasian Keelback Snakes (Natricidae: Tropidonophis Jan, 1863). Jackson Roberts*, Louisiana State University; Bulisa Iova, Papua New Guinea National Museum and Art Gallery; Fred Kraus, University of Michigan; Allen Allison, Bernice P. Bishop Museum; Christopher Austin, Louisiana State University roberts.jackson265@gmail.com
Australasian Keelback Snakes (Natricidae: Tropidonophis Jan, 1863) comprise a diverse lineage of Pacific aquatic snakes that have had limited investigations of their systematics and evolutionary history. Biogeographically, these aquatic snakes are widespread with a distribution that spans three major Pacific biogeographic barriers: Wallace's, Weber's, and Lydekker's Lines. Despite growing contemporaneous field collections, no study to date has used high throughput sequencing to assess phylogenetic relationships in this group. Using thousands of ultraconserved elements (UCEs), we constructed the most comprehensive (14 of 20 species) phylogenies, species trees, and biogeographical hypotheses for this genus. We found Tropidonophis to be monophyletic, and that this genus originated in the Philippines during the mid-to-late Miocene (~8-14 mya). In addition, New Guinea Tropidonophis are strongly supported as monophyletic, with a most recent common ancestor that appears to have dispersed to New Guinea through use of a stepping-stone model across oceanic island arcs from the Philippines to New Guinea during the late Miocene. Tectonic oceanic arc movements transported these islands closer to the Australian (Sahul) Shelf during the early Pliocene. Island arc tectonic movement served first as a physical dispersal transporter, and subsequent arc accretion and mountain building of the Central Cordillera drove allopatric speciation on mainland New Guinea. |
|
6. 11:15 More than Meets the Eye: Widespread UV Reflectance Across the Snake Tree of Life is Structured by Ontogeny and Ecology. Hayley Crowell*, University of Michigan; John David Curlis, University of Michigan; Hannah Weller, Brown University; Alison Davis Rabosky, University of Michigan hlcrowel@umich.edu
UV (ultra-violet) reflective coloration is present across many vertebrate taxa and is particularly well-studied as a mechanism of social signaling and sexual selection in lizards. Additionally, research on UV reflectance generally assumes that UV reflectance is the exception and not the rule, with the implied null hypothesis that it should be near-absent in species with minimal sexual dichromatism. To test for UV coloration in a system that does not rely on color cues for intraspecific communication, we used multispectral imaging to photograph the dorsal and ventral sides of 432 individuals representing 108 neotropical snake species in both visible and UV light spectra. We scored individuals for the presence of UV reflection and quantified average percentage body coverage of UV-reflective coloration, reflectance intensity, and which scale colors in the visible spectrum produced UV-reflectance across body parts. Overall, the majority of snake species were recorded as having UV reflectance. We found that age, diel activity cycles, and habitat were the strongest predictors of UV-reflectance. Importantly, we found that coloration in the visible spectrum has little power for predicting reflectance in UV spectra, such that the full reflectance profile of a snake is simply not quantifiable from the color pattern visible to the human eye alone. We detected low phylogenetic signal in our analyses, suggesting that this trait may be under selection and that future potential for major research discoveries regarding the adaptive purpose of these “invisible” elements is high. |
|
7. 11:30 Trends in Indian herpetology over the last 70 years: A view from scientific pursuit and gender lenses. Vivek Cyriac, The Liana Trust; Sneha Dharwadkar*, Freshwater Turtles and Tortoises Foundation; Anuja Mital, Freshwater Turtles and Tortoises Foundation; Ashwini Mohan, Department of Evolutionary Biology, Zoological Institute, Braunschweig University of Technology sneha.dharwadkar@okstate.edu
Herpetology in India has grown rapidly since India’s independence in 1947, in terms of studies published. Many studies have outlined the history of herpetology pre-independence, but few have traced the growth of this field since India’s independence. We analysed trends in Indian herpetology focusing on authorship, subfields, and taxa over approximately the past 70 years (1947-2019). We analysed 1177 scientific papers. Gender-wise, the ratio was male-dominated, with only 29.7% of articles having women authors. Only 14.8% of articles had women as first authors, and 15% had women as corresponding authors. The overall proportion of women authors has not changed significantly over decades, but we detected a significant decrease in women first authors and the proportion of women authors when the corresponding authors were men. Women authors were substantially lower in the subfield of Taxonomy & Systematics, and women published significantly more on amphibians compared to reptiles. We found a significantly greater number of publications on Diversity & Distribution (34.2%), Taxonomy & Systematics (21.5%) and Ecology (19.2%) compared to other subfields, and there were far more publications on reptiles (64.9%) compared to amphibians (26.5%) and overall herpetofaunal studies (8.6%). Overall, we highlight the growth of herpetology in India from two key viewpoints: gender parity among herpetologists and scientific pursuits. |