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    Amphibian Biogeography and Systematics

    2021-07-23   13:45 - 15:30

    Moderator: Eli Greenbaum

    1.  13:45  VIRTUAL    Effects of Corticosterone on Salamander Immunity and Behavior. Kenzie Pereira*, Duquesne University; Jenna Mulreany, Duquesne University; Sarah Woodley, Duquesne University

    Emerging infectious diseases (EIDs) drive wildlife biodiversity loss. Because EID outbreaks have been associated with environmental stressors, it is broadly hypothesized that susceptibility is influenced by the host’s stress response, which is characterized by elevations in circulating glucocorticoid hormones (GCs). GCs are known to modulate changes in immunity and behavior, thereby, influencing host-susceptibility to disease. Amphibians face numerous natural and anthropogenic stressors that elevate circulating GC levels. We used the salamander model, Notophthalmus viridescens, to test the hypothesis that elevations in GC levels alter innate and adaptive immune function, and behavior. We predicted that short-term GC elevations will be immunoenhancing, while long-term elevations will be immunosuppressive. To do this, captive adult newts were treated with repeated exogenous corticosterone (CORT, primary GC in amphibians) doses over one (short-term treatment) or four-weeks (long-term treatment) using established methods for increasing plasma CORT. We estimated innate immunity by quantifying neutrophil-lymphocyte ratios, bacteria killing ability of plasma compliment proteins, and lysozyme from stomach tissue. We estimated adaptive immunity by quantifying lymphocytes in spleen tissue and melanomacrophage centers in liver tissue. Prior to collecting immunity data, we recorded behavior videos. Videos were analyzed in Image J. The analyses of immunity and behavioral data are currently underway.

    2.  14:00  IN-PERSON    Lost and found: a 10-year review and analysis of recently rediscovered amphibian species. Luke Linhoff*, Smithsonian's National Zoo and Conservation Biology Institute; Allison Bryne, Smithsonian's National Zoo and Conservation Biology Institute; Randall Jimenez, Smithsonian's National Zoo and Conservation Biology Institute; Roberto Ibanez, Smithsonian Tropical Conservation Research Institute; Carly Muletz Wolz, Smithsonian's National Zoo and Conservation Biology Institute; Brian Gratwicke, Smithsonian's National Zoo and Conservation Biology Institute

    Discerning if rare, cryptic species are extinct may require considerable effort, time and funding. Lengthy gaps spanning years or decades between confirmed sightings of individual species hampers effective monitoring and conservation planning. While the number of threatened and extinct amphibian species continues to increase, paradoxically, many species thought to be extinct have been rediscovered. These rediscovered species may even be found outside their historical distributions, either after making meticulous surveys or by accident. Rediscoveries of supposedly extinct species can garner intense media coverage and even controversy. We will review and discuss several issues relating to publications of rediscovered amphibian species. First, the terminology relating to rediscoveries is inconsistent across the scientific literature and popular media. Secondly, there has not been a systematic review of amphibian rediscoveries since 2010. Analyzing rediscoveries of amphibians in the last ten years are particularly relevant because one of the primary drivers of global amphibian declines has been the amphibian chytrid fungus disease. But there have been a number of indicators that some species have recently rebounded following initial catastrophic declines. In our current study we: 1) define multiple categories of rediscovery types and quantify all amphibians rediscovered in the last 10 years, 2) explore the geographic and taxonomic variety of amphibian rediscoveries, 3) examine if there has been an increase in species rediscovers in the last ten years compared to previous decades by connecting our dataset to previously published information by Scheffers et al. 2011. Results will be presented.

    3.  14:15  IN-PERSON    Evolution of African spiny reed frogs (Anura: Hyperoliidae: Afrixalus), with the description of a new species from the Albertine Rift. Eli Greenbaum*, University of Texas at El Paso; Daniel Portik, California Academy of Sciences; Kaitlin Allen, University of Kansas; Michael Barej, Museum für Naturkunde Berlin; Nancy Conkey, University of Texas at El Paso; Legrand Nono Gonwouo, University of Yaoundé I; Mareike Hirschfeld, Museum für Naturkunde Berlin; Félix Igunzi Alonda, Réserve Naturelle d’Itombwe; Chifundera Kusamba, Centre de Recherche en Sciences Naturelles; Jesús Reyes, University of Texas at El Paso

    The Albertine Rift of Central Africa is renowned as the most species-rich montane area in continental Africa, but paradoxically, much of its biodiversity remains poorly known. Herein, we focus on the region’s spiny reed frogs of the genus Afrixalus (Anura: Hyperoliidae) to elucidate their phylogenetic relationships, identify cryptic species, and understand historical processes that contributed to their speciation patterns within the Rift. Approximately 2,040 base pairs of mitochondrial (16S and cyt b) and nuclear (RAG1) genes were sequenced from 25 Afrixalus samples. Maximum-likelihood, Bayesian inference, and multiple species-delimitation analyses of these data and additional samples from GenBank demonstrated thatthe populations from the Albertine Rift previously assigned to A. laevisare an undescribed taxon, which we describe as a new species. Dating analyses with BEAST confirm patterns from previous studies that a global cooling trend in the late Miocene/early Pliocene likely isolated populations of forest-endemic amphibians within highland refugia of the Rift, leading to their allopatric speciation.

    4.  14:30  IN-PERSON    Systematics of the cryptic frog complexLimnonectes kuhlii (Anura: Dicroglossidae) from volcanic regions of Java and Sumatra. Thornton Larson*, University of Texas at Arlington; Thomas Firneno, University of Texas at Arlington; Amir Hamidy, Museum Zoologicum Bogoriense, Indonesian Institute of Sciences; Nia Kurniawan, Brawijaya University; Matthew Fujita, University of Texas at Arlington; Eric Smith, University of Texas at Arlington

    The cryptic species group Limnonectes kuhlii currently consists of over 22 identified lineages across Southeast Asia, many of which remain undescribed. Furthermore, Indonesia has remained poorly explored, and the exact number of lineages within even the larger Sunda islands remains unknown. In an ongoing study to evaluate the evolutionary relationships and identify cryptic species within the group, 12S through 16S were sequenced, along with ddRADs from 64 samples across the islands of Java and Sumatra; 31 additional samples which contain sequences from 12S through 16S regions were included from GenBank. Data were analyzed with maximum-likelihood and Bayesian inference criteria using RAxML-HPC BlackBox v.8.2.12 and MRBAYES v.3.2.7a on the CIPRES Science Gateway. Appropriate models of nucleotide substitution were identified in the program jModelTest v2.1.10. Species trees and divergence times were generated in BEAST v.2.6.1. Population structure was revealed using STRUCTURE, Admixture, and the FRS package in R. Results demonstrate four large clades between the islands of Sumatra and Java. Double-digest RADseq data further supports these clades and demonstrate deeper population structure within those clades. Careful consideration of type material to determine “true” L. kuhlii still present a challenge for some clades in Java and southern Sumatra, but these lineages suggest the taxonomic diversity of the L. kuhliigroup remains underestimated.

    5.  14:45  VIRTUAL    Occurrence of Shasta Salamanders (Hydromantesspp.) in Little-Studied Portions of Their Range, with Implications for Optimizing Survey Design. Brian Halstead*, U.S. Geological Survey, Western Ecological Research Center; Patrick Kleeman, U.S. Geological Survey, Western Ecological Research Center; Graziella DiRenzo, U.S. Geological Survey, Massachusetts Cooperative Fish and Wildlife Research Unit; Jonathan Rose, U.S. Geological Survey, Western Ecological Research Center

    Shasta salamanders (collectively, Hydromantes samweli, H. shastae, and H. wintu; hereafter Shasta salamander) are endemic to northern California in the general vicinity of Shasta Lake reservoir. Although generally associated with limestone, they have repeatedly been found in association with other habitats, calling into question the distribution of the species complex. Further limiting our knowledge of the species’ distributions is that they are only active or available for sampling on the soil surface for a small portion of the year, and detection probabilities for the species have never been estimated. We developed and implemented a survey protocol designed to estimate detection, availability, and occurrence probabilities from December 2019 through March 2020, and used it to provide inference on Shasta salamander occurrence in portions of their range that have received little survey effort. We found that Shasta salamander occurrence was positively associated with the percent cover of embedded rock, and their availability (i.e., probability of being active on the soil surface during sampling) was positively related to relative humidity. The probability of occurrence of Shasta salamanders in our study area was low, and our winter-to-spring survey protocol was effective for estimating detection, availability, and occurrence probabilities in the study area and at specific sites. Our results indicate that conducting replicate surveys that quantify animal availability and detection probabilities will facilitate a better understanding of the habitat associations of Shasta salamanders and other rare species that might often be unavailable for detection.

    6.  15:00  VIRTUAL    Cryptic and Elevational Diversification in Sulawesi Fanged Frogs (Genus: Limnonectes). Jeffrey Frederick*, UC Berkeley; Djoko Iskandar, Bandung Institute of Technology; Jim McGuire, UC Berkeley

    The radiation of fanged frogs on the Indonesian island of Sulawesi features stunning variation in morphology, reproductive modes, and microhabitat use. However, the extent of Limnonectes species diversity on the island remains poorly understood with only a small fraction of the known species having been formally described. This challenge is due in part to the difficulty in discriminating between morphologically and phenotypically similar animals, as well as in recognizing when morphological variation reflects interspecific versus intraspecific differentiation. Here, we report findings from our ongoing investigations of Sulawesi Limnonectes, focusing on the monophyletic assemblage largely confined to Sulawesi’s Southwest Peninsula. Using an integrative approach that includes extensive field sampling, phylogenomic analysis of exome-capture data, morphometrics, and acoustic analyses, we reveal an example of cryptic speciation as well as two remarkable examples of apparent elevational speciation. Whereas two species of Limnonectes have been reported in the literature from the Southwest Peninsula, we find that this clade is actually comprised of six species, five of which are restricted to the Southwest Peninsula, south of the Tempe Depression biogeographical boundary.

    7.  15:15  VIRTUAL    Using Geometric Morphometrics to Evaluate the Diversity Within the Genus Siren. Joshua Rivera*, Southeastern Louisiana University; Christopher Murray, Southeastern Louisiana University; Brian Crother, Southeastern Louisiana University

    Sirenids are enigmatic in their biology, behavior, and phylogenetic relationships. These eel-like salamanders are morphologically unique, with slender bodies and absent lower extremities. Species in the genusSirenall maintain this body plan, with some slight variation in phenotype and body length. Additionally, these species sometimes have sympatric distributions. These attributes can present a challenge in differentiatingSirenat the species level. The phylogenetic reconstruction from Graham et al. (2018) suggested that certain populations ofSiren intermediawere more closely related toSiren lacertinathan to conspecific populations. This study employs geometric morphometric analyses to evaluate this paraphyletic relationship and compare interspecific morphological variation. Using these analyses, we have quantified variation in morphology among different species within the genusSiren, as well as populations ofSiren intermediafrom throughout their distribution. Canonical variates analyses, principal components analyses, and Procrustes ANOVAs were conducted using dorsal head morphology. The results of this study suggest that the purportedSiren intermedia nettingiandSiren intermedia intermedia, are morphologically distinct. Reevaluating species within this genus, i.e. elevation from subspecies to species, may have conservation implications moving forward.

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