Ecology and Evolutionary Biology Commons^™

American Bullfrog (Lithobates Catesbeianus) Diet In Uruguay Compared With Other Invasive Populations In Southern South America, Gabriel Laufer, Noelia Gobel, Mauro Berazategui, Matías Zarucki, Sofía Cortizas, Alvaro Soutullo, Claudio Martinez Debat, Rafael O. De Sá

Biology Faculty Publications

Between 2000-2020, more than ten new populations of the invasive American bullfrog (Lithobates catesbeianus) have been reported in the southern cone of South America. We studied the stomach contents of 126 bullfrogs from a population at an early invasion stage in Uruguay (Acegua, Cerro Largo Department). We observed a rich diet, with extensive prey volume range (1 mm3 to more than 7 000 mm(3)); the most frequent items were Hymenoptera (19.6%), Coleoptera (16.4%), Amphipoda (13.3%), Anura (8.9%) and Heteroptera (8.7%). Despite some overlap, differences were observed in volume (chi(2) = 54.6, p <0.001, d.f. = 2) and prey quantity (F = 8.1, p <0.001, d.f. = 79) between males, females, and juveniles. Juveniles showed significantly higher consumption of terrestrial prey by count (82% of their total ingestion) than adults (29% for males and 32% for females) (chi(2) = 28.5, p <0.001, d.f. = 2). Adults, especially females, showed a high frequency of cannibalism (33% of their total ingestion; chi(2) = 20.9, p <0.001, d.f. = 2). Comparing our data with other bullfrog regional studies, we found great plasticity in trophic habits and differences in the incidence of cannibalism (higher incidence in the populations of Acegua, Uruguay, and Buenos Aires, Argentina). These differences could be related to local biodiversity, but also could be affected by the invasion phase. Cannibalism frequency was higher in small bullfrog populations, where it could be favoring the establishment success. This shift in foraging strategies during the invasion process had been insufficiently evaluated in amphibians. Knowing the ecological determinants for the invasion by bullfrogs can be useful to the development of management strategies.

Larval Chondrocranial And Internal Oral Morphology Of The Neotropical Treefrog Boana Crepitans (Wied-Neuwied, 1824; Amphibia, Anura, Hylidae), Marianna Isabella Rosa Rodrigues De Oliveira, Luiz Norberto Weber, Johnny Sousa Ferreira, Anna Evelin Coimbra Liborio, André Masahide Guimaraes Takazone, Rafael O. De Sá

Biology Faculty Publications

We describe the internal oral morphology and chondrocranial anatomy for Boana crepitans tadpoles, and compare them with available descriptions for other species in the subfamily Cophomantinae. Among species of the Boana faber group, the chondrocranial anatomy has been reported only for one species internal oral morphology and cranial anatomy are similar to other described species of Boana and Cophomantinae. B. crepitans lacks unique features in the oral cavity and chondrocranium that would distinguish it from other congeneric species. We identify six characters from the internal oral anatomy of tadpoles unique for Cophomantinae. In addition, Boana has infralabial papillae projections, buccal …

Larval Anatomy Of Monotypic Painted Ant Nest Frogs Lithodytes Lineatus Reveals Putative Homoplasies With The Leptodactylus Pentadactylus Group (Anura: Leptodactylidae), Filipe A.C Do Nascimento, Rafael O. De Sá, Paulo C. De A. Garcia

Biology Faculty Publications

The morphological diversity of anuran larvae made them an important source of information for evolutionary and systematic studies. For the monotypic frog genus Lithodytes, which has an interesting taxonomic history, including its past synonymizing with Adenomera and its placement as a subgenus of Leptodactylus, the information provided from its larvae can help to understand its systematics interrelationships and also provide insights about its evolutionary trajectories. Herein, we provide a detailed description of the larval morphology of Lithodytes lineatus, including novel data of internal morphology (buccopharyngeal cavity and skeleton), and discuss some morphological and evolutionary aspects in relation …

Taxonomic Review Of South American Butter Frogs: Phylogeny, Geographic Patterns, And Species Delimitation In The Leptodactylus Latrans Species Group (Anura: Leptodactylidae), Felipe De M. Magalhães, Mariana L. Lyra, Thiago R. De Carvalho, Diego Baldo, Francisco Brusquetti, Pamela Burella, Guarino R. Colli, Marcelo C. Gehara, Rafael O. De Sá, Et Al.

Biology Faculty Publications

The Leptodactylus latrans species group currently comprises eight medium- to large-sized frog species with a convoluted taxonomic history, particularly related to the specific limits of the L. latrans complex, and the species pair Leptodactylus chaquensis–Leptodactylus macrosternum. Their homogeneous external morphology and continental geographic distribution in South America have posed severe limitations to a comprehensive review, such that taxonomic consensus and species limits remain uncertain. This is further worsened by the presence of chromatic polymorphism among coexisting species that can hardly be distinguished by external morphology. Based on a large-scale geographic sampling including multilocus DNA analyses, and acoustic …

Climate-Related Geographical Variation In Performance Traits Across The Invasion Front Of A Widespread Non-Native Insect, Lily M. Thompson, Sean D. Powers, Ashley Appolon, Petra Hafker, Leila Milner, Dylan Parry, Salvatore J. Agosta, Kristine L. Grayson

Biology Faculty Publications

Aim

Invasive species are ideal systems for testing geographical differences in performance traits and measuring evolutionary responses as a species spreads across divergent climates and habitats. The European gypsy moth, Lymantria dispar dispar L. (Lepidoptera: Erebidae), is a generalist forest defoliator introduced to Medford, Massachusetts, USA in 1869. The invasion front extends from Minnesota to North Carolina and the ability of this species to adapt to local climate may contribute to its continuing spread. We evaluated the performance of populations along the climatic gradient of the invasion front to test for a relationship between climate and ecologically important performance traits. …

Presence And Distribution Of Leptodactylus Guianensis Heyer And De Sa, 2011 In Colombia: Comparisons With Other Species In The L. Latrans Group., Mariela Osorno Muñoz, Doris L. Gutiérrez-Lamus, Rafael O. De Sá

Biology Faculty Publications

Leptodactylus guianensis is reported for the first time for Colombia along with a distributional map of the species. The species is the fifth species of the L. latransspecies group documented in the country. Males possess a single, conical and slightly chisel-shaped thumb spine; only three species in the group have a single thumb spine. In collections, specimens of L. guianensis are misidentified as L. macrosternum, L. latrans or L. bolivianus. We provide morphological, colouration and habitat descriptions for where the species occurs in Colombia.

Multiple Connections Between Amazonia And Atlantic Forest Shaped The T Phylogenetic And Morphological Diversity Of Chiasmocleis Mehely, 1904 (Anura: Microhylidae: Gastrophryninae), Rafael O. De Sá, João Filipe Riva Tonini, Hannah Van Huss, Alex Long, Travis Cuddy, Mauricio C. Forlani, Pedro L.V. Peloso, Hussam Zaher, Célio F.B. Haddad

Biology Faculty Publications

Chiasmocleis is the most species-rich genus of Neotropical microhylids. Herein, we provide the first comprehensive multilocus phylogeny for the genus, including all but 3 of the 34 recognized species and multiple individuals per species. We discuss cryptic speciation, species discovery, patterns of morphological evolution, and provide a historical biogeographic analysis to account for the current distribution of the genus. Diversification of Chiasmocleis from other New World microhylids began during the Eocene, app. 40 mya, in forested areas, and current diversity seems to be a product of recurrent connections between the Atlantic Forest and Amazonia. Small-sized species evolved independently three times …

Review Of The Family Rivulidae (Cyprinodontiformes, Aplocheiloidei) And A Molecular And Morphological Phylogeny Of The Annual Fish Genus Austrolebias Costa 1998, Marcelo Loureiro, Rafael O. De Sá, Sebastián W. Serra, Felipe Alonso, Luis Esteban Krause Lanés, Matheus Vieira Volcan, Pablo Calviño, Dalton Nielsen, Alejandro Duarte, Graciela Garcia

Biology Faculty Publications

The family Rivulidae is the fourth most diverse clade of Neotropical fishes. Together with some genera of the related African family Nothobranchiidae, many rivulids exhibit a characteristic annual life cycle, with diapausing eggs and delayed embryonic development, which allows them to survive in the challenging seasonal ponds that they inhabit. Rivulidae also includes two species known as the only the self-fertilizing vertebrates and some species with internal fertilization. The first goal of this article is to review the systematics of the family considering phylogenetic relationships and synapomorphies of subfamilial clades, thus unifying information that is dispersed throughout the literature. From …

First Record Of The Genus Leptodactylus (Anura: Leptodactylidae) In Cuba: Leptodactylus Fragilis, A Biological Invasion?, Tomás M. Rodríguez-Cabrera, L. Yusnaviel García-Padrón, Andrés R. Acosta Galvis, Rafael O. De Sá, Roberto Alonso Bosch

Biology Faculty Publications

The Neotropical genus Leptodactylus is currently represented by three species in the West Indies (Leptodactylus albilabris, Leptodactylus fallax and Leptodactylus validus). Based on morphological, acoustic and molecular evidence, we document the presence of a fourth species in the Caribbean region, Leptodactylus fragilis (Brocchi, 1877). The species was found at two localities in western Cuba, and molecular data suggest a northern South American origin, possibly Venezuela, for these populations. We discuss the potential invasive status of L. fragilis, based on its known distribution, relative abundance, behaviour and possible impacts on native species of Cuban amphibians.

Cross-Life Stage Effects Of Aquatic Larval Density And Terrestrial Moisture On Growth And Corticosterone In The Spotted Salamander, Julie F. Charbonnier, Jacquelyn Pearlmutter, James R. Vonesh, Caitlin R. Gabor, Zachery R. Forsburg, Kristine L. Grayson

Biology Faculty Publications

For organisms with complex life cycles, conditions experienced during early life stages may constrain later growth and survival. Conversely, compensatory mechanisms may attenuate negative effects from early life stages. We used the spotted salamander, Ambystoma maculatum, to test how aquatic larval density and terrestrial moisture influence juvenile growth, food intake, evaporative water loss and water reuptake rates, and corticosterone levels. We conducted an outdoor mesocosm experiment to manipulate larval density and transferred metamorphosed salamanders into low and high terrestrial moisture treatments in laboratory terrariums. After the larval stage, high-density salamanders were significantly smaller and had higher corticosterone release rates …

Thermal Physiology And Developmental Plasticity Of Pigmentation In The Harlequin Bug (Hemiptera: Pentatomidae), Carly D. Sibilia, Kelly A. Brosko, Christopher J. Hickling, Lily M. Thompson, Kristine L. Grayson, Jennifer R. Olson

Biology Faculty Publications

Traits that promote the maintenance of body temperatures within an optimal range provide advantages to ectothermic species. Pigmentation plasticity is found in many insects and enhances thermoregulatory potential as increased melanization can result in greater heat retention. The thermal melanism hypothesis predicts that species with developmental plasticity will have darker pigmentation in colder environments, which can be an important adaptation for temperate species experiencing seasonal variation in climate. The harlequin bug (Murgantia histrionica, Hemiptera: Pentatomidae, Hahn 1834) is a widespread invasive crop pest with variable patterning where developmental plasticity in melanization could affect performance. To investigate the impact of temperature …

Geographic Variation In Larval Metabolic Rate Between Northern And Southern Populations Of The Invasive Gypsy Moth, Carolyn May, Noah Hillerbrand, Lily M. Thompson, Trevor M. Faske, Eloy Martinez, Dylan Perry, Salvatore J. Agosta, Kristine L. Grayson

Biology Faculty Publications

Thermal regimes can diverge considerably across the geographic range of a species, and accordingly, populations can vary in their response to changing environmental conditions. Both local adaptation and acclimatization are important mechanisms for ectotherms to maintain homeostasis as environments become thermally stressful, which organisms often experience at their geographic range limits. The spatial spread of the gypsy moth (Lymantria dispar L.) (Lepidoptera: Erebidae) after introduction to North America provides an exemplary system for studying population variation in physiological traits given the gradient of climates encompassed by its current invasive range. This study quantifies differences in resting metabolic rate (RMR) across …

Leptodactylus Validus Garman, 1888 In Colombia: Its Distribution And Identification, Andres R. Acosta Galvis, Rafael O. De Sá

Biology Faculty Publications

Leptodactylus validus is reported for the first time for Colombia, corresponding to the tenth species of the L. melanonotus species group occurring in the country. In collections, all L. validus specimens were identified as L. colombiensis. Morphological, coloration, and ecological characters are provided to differentiate the two species in Colombia. Furthermore, the distribution of L. validus is expanded based on the examination of specimens in both collections and literature records. In addition, the advertisement call of L. validus from Colombia is compared with those reported for other continental and insular populations; the calls are slightly more similar to those …

Physiological Responses To Elevated Temperature Across The Geographic Range Of A Terrestrial Salamander, Alexander J. Novarro, Caitlin R. Gabor, Cory B. Goff, Tori D. Mezebish, Lily M. Thompson, Kristine L. Grayson

Biology Faculty Publications

Widespread species often possess physiological mechanisms for coping with thermal heterogeneity, and uncovering these mechanisms provides insight into species responses to climate change. The emergence of non-invasive corticosterone (CORT) assays allows us to rapidly assess physiological responses to environmental change on a large scale. We lack, however, a basic understanding of how temperature affects CORT, and whether temperature and CORT interactively affect performance. Here, we examine the effects of elevated temperature on CORT and whole-organism performance in a terrestrial salamander, Plethodon cinereus, across a latitudinal gradient. Using water-borne hormone assays, we found that raising ambient temperature from 15 to 25°C …

Current Status Of American Bullfrog, Lithobates Catesbeianus, Invasion In Uruguay And Exploration Of Chytrid Infection, Gabriel Laufer, Noelia Gobel, Claudio Borteiro, Alvaro Soutullo, Claudio Martinez-Debat, Rafael O. De Sá

Biology Faculty Publications

The American bullfrog Lithobates catesbeianus is an invasive species that can strongly affect native amphibian communities through competition, predation, or introduction of diseases. This frog has invaded multiple areas in South America, for which niche models predict suitable environments across much of the continent. This paper reveals the state of the invasion of this species in Uruguay and its possible relationship with the chytrid pathogenic fungus, Batrachochytrium dendrobatidis. Surveys at invaded sites were conducted from 2007 to 2015, identified two populations undergoing recent range expansion (one of them exponential), two populations that failed to establish, and a new record …

Chondrocranium And Internal Oral Morphology Of The Tadpole Of Corythomantis Greeningi (Anura: Hylidae), Marianna Isabella Rosa Rodrigues De Oliveira, Luiz Norberto Weber, Rafael O. De Sá, Johnny Sousa Ferreira, Anna Evelin Coimbra Libório, André Masahide Guimarães Takazone

Biology Faculty Publications

Corythomantis greeningi is a casque-headed frog that occurs in xeric and sub-humid regions of northeastern Brazil. Individuals are often found on rocks on banks of temporary streams or in ponds upon “lajedos”. Suctorial tadpoles are often found clasping to the rocks in the streams so as not to be dragged by the current; therefore, they have modified external and internal morphology. Here, we describe the internal oral anatomy and the chondrocranium of the tadpole of C. greeningi and compare it to the available descriptions of Lophyohylinae and other suctorial tadpoles. The internal oral morphology in C. greeningi resembles pond-dwelling casque-headed …

A Global Community Effort To Decipher The Unique Biology Of Annual Killifish, Nibia Berois, Graciela Garcia, Rafael O. De Sá

Biology Faculty Publications

Over the past 50 years, annual killifishes arose as alternative model organisms for studies of vertebrate biology. The annual fish offers exceptional advantages for studies of genetics, genomics, developmental biology, population dynamics, ecology, biogeography, and evolution. They inhabit extremely variable freshwater environments in Africa and South America, have a short lifespan and a set of unique and fascinating developmental characteristics. Embryos survive within the dry substrate during the dry season, whereas the adult population dies. Thus, the survival of the populations is entirely dependent on the buried embryos that hatch the next rainy season. Although Old and New World species …

Assessment Of The Calling Detection Probability Throughout The Day Of Two Invasive Populations Of Bullfrog (Lithobates Catesbeianus) In Uruguay, Gabriel Laufer, Noelia Gobel, Alvaro Soutullo, Claudio Martinez-Debat, Rafael O. De Sá

Biology Faculty Publications

Bullfrog invasion is a major conservation concern in South America, so there is an urgent need to detect and monitor its many invasion foci. Amphibian sampling methods commonly use calling display, specifically the nuptial calls of males. With the aim of obtaining the better day period to sample and monitor Lithobates catesbeianus presence, we recorded its calls at three ponds in two invaded localities in Uruguay (Aceguá, Cerro Largo, and San Carlos, Maldonado) during the reproductive season. Then, we studied the records, obtaining a subsample of calling intensity at the first 5 minutes for each hour. We detected that vocalization …

Molecular And Morphological Data Reveal Three New Cryptic Species Of Chiasmocleis (Mehely 1904) (Anura, Microhylidae) Endemic To The Atlantic Forest, Brazil, Mauricio C. Forlani, João F. R. Tonini, Carlos A. G. Cruz, Hussam Zaher, Rafael O. De Sá

Biology Faculty Publications

Three new cryptic species of Chiasmocleis from the Atlantic Forest of Brazil are described. Two of these species occur in the northeastern states of Sergipe and Bahia, whereas the third species is found in the southeastern state of São Paulo. The new species can be distinguished from other congeneric species by the molecular data, as evidenced in the phylogeny, and by a combination of morphological characters including: size, foot webbing, dermal spines, and coloration patterns. Chiasmocleis species differ in osteological traits, therefore we also provide an osteological description of each new species and comparisons with data reported for other species …

Photography-Based Taxonomy Is Inadequate, Unnecessary, And Potentially Harmful For Biological Sciences, Luis M. P. Ceríaco, Eliécer E. Gutiérrez, Alain Dubois, Rafael O. De Sá, Et Al.

Biology Faculty Publications

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per …

Endless Symbioses Most Intricate, W. John Hayden

Biology Faculty Publications

Orchids, such as our Wildflower of the Year for 2016, Downy Rattlesnake Plantain (Goodyera pubescens) (Fig. 1), exemplify the interconnectedness of life on Earth. As would be the case for many kinds of plants, pollination comes readily to mind as a prominent example of mutualistic symbiosis. Downy Rattlesnake Plantain is pollinated by bumblebees and other native bees. The bees gain nectar and the orchid gets an efficient means to move pollen from one flower to another; each organism gains benefit from the interaction, the very definition of mutualism. Pollination by bees is widespread among the orchids, but there …

Seed Dispersal: A Tale Of Two Species, W. John Hayden

Biology Faculty Publications

Orchids have minute, dustlike seeds. In this respect, Goodyera pubescens (Downy Rattlesnake Plantain), the 2016 VNPS Wildflower of the Year, is a typical orchid. Like all other orchids, Goodyera seeds contain little more than a few embryonic cells enclosed in a thin seed coat. There are two advantages to small seed size in orchids: minute seeds can be produced in prodigious quantities, and they can disperse over great distances by wind.

High Genetic Diversity But Low Population Structure In The Frog Pseudopaludicola Falcipes (Hensel, 1867) (Amphibia, Anura) From The Pampas Of South America, José A. Langone, Arley Camargo, Rafael O. De Sá

Biology Faculty Publications

Relative to South America’s ecoregions, the temperate grasslands of the Pampas have been poorly studied from a phylogeographic perspective. Based on an intermediate biogeographic setting between subtropical forest (Atlantic Forest) and arid ecosystems (Chaco and Patagonia), Pampean species are expected to show unstable demographic histories due to the Quaternary climatic oscillations. Herein, we investigate the phylogenetic relatedness and phylogeographic history of Pseudopaludicola falcipes, a small and common frog that is widely distributed across the Pampean grasslands. First, we use molecular data to assess if P. falcipes represents a single or multiple, separately evolving cryptic lineages. Because P. falcipes is …

Book Reviews, Robert D. Aldridge, Michael B. Thompson, Malorie M. Hayes, Rafael O. De Sá, Christopher G. Lowe

Biology Faculty Publications

Reproductive Biology and Phylogeny of Lizards and Tuatara. J. L. Rheubert, D. S. Siegel, and S. E. Trauth (Eds.). 2014. CRC Press. ISBN 9781466579866. 760 p. $143.96 (hardcover).—

According to the authors, this book was intended to summarize the current knowledge of phylo- geny and reproduction of the Lepidosauria. I believe the authors have achieved their goal. Many of the chapters in this book are derived from presentations that took place at the Symposium on Reproductive Biology of Lizards at the Joint Meeting of Ichthyologists and Herpetologists held in Chattanooga, Tennessee in 2014. Although the majority of the authors are …

Systematics Of The Neotropical Genus Leptodactylus Fitzinger, 1826 (Anura: Leptodactylidae): Phylogeny, The Relevance Of Non-Molecular Evidence, And Species Accounts, Rafael O. De Sá, Taran Grant, Arley Camargo, W. R. Heyer, María Laura Ponssa, Edward Stanley

Biology Faculty Publications

A phylogeny of the species-rich clade of the Neotropical frog genus Leptodactylus sensu stricto is presented on the basis of a total evidence analysis of molecular (mitochondrial and nuclear markers) and non-molecular (adult and larval morphological and behavioral characters) sampled from > 80% of the 75 currently recognized species. Our results support the monophyly of Leptodactylus sensu stricto, with Hydrolaetare placed as its sister group. The reciprocal monophyly of Hydrolaetare and Leptodactylus sensu stricto does not require that we consider Hydrolaetare as either a subgenus or synonym of Leptodactylus sensu lato. We recognize Leptodactylus sensu stricto, Hydrolaetare, Adenomera, and Lithodytes …

Persistence And Stability Of Eastern Afromontane Forests: Evidence From Brevicipitid Frogs, Simon P. Loader, F. Sara Ceccarelli, Michele Menegon, Kim M. Howell, Roman Kassahun, Abebe A. Mengistu, Samy A. Saber, Fikirte Gebresenbet, Rafael O. De Sá, Et Al.

Biology Faculty Publications

Aim: The persistence and stability of habitats through time are considered predictors of high levels of biodiversity in some environments. Long-term habitat persistence and stability may explain the species-rich, endemic forest fauna and flora of the Eastern Afromontane Biodiversity Region (EABR). Using comple- mentary phylogenetic and biogeographical approaches, we examine evolution- ary patterns in EAR brevicipitid frogs. Using these data, we test whether brevicipitid history reflects patterns of long-term forest persistence and/or sta bility across the EABR.

Location: East Africa.

Methods: A dated phylogeny for brevicipitids was constructed using two nuclear and three mitochondrial markers. Alternative diversification modes were used …

A Threat To New Zealand's Tuatara Heats Up, Kristine L. Grayson, Nicola J. Mitchell, Nicola J. Nelson

Biology Faculty Publications

No matter how many times we head to one of New Zealand's offshore islands, the feelings are always a mix of sheer awe at the beauty and biodiversity preserved in these special refuges and lingering nerves. Did we remember all the gear? Do we have enough food and water in case we get stuck? Can the helicopter land on the side of a cliff in these winds? These epic journeys are in pursuit of a lone remnant of the reptile evolutionary tree, with a unique ecology that has big implications under climate change.

A New Species Of Chiasmocleis (Microhylidae, Gastrophryninae) From The Atlantic Forest Of Espírito Santo State, Brazil, João Filipe Tonini, Maruicio Forlani, Rafael O. De Sá

Biology Faculty Publications

Among Neotropical microhylids, the genus Chiasmocleis is exceptionally diverse. Most species ofChiasmocleis were described in recent years based on external morphology, but recent studies using molecular data did not support the monophyly of the species groups clustered based on feet webbing. Furthermore, a phylogeographic study of C. lacrimae estimated high genetic divergence and low gene flow among populations across small geographic ranges. Increasing the molecular and geographic sampling, and incorporating morphological data, we identified new cryptic species. Herein, we used novel genetic and morphological data to describe a new species of Chiasmocleis.

The Neotropical Genus Austrolebias: An Emerging Model Of Annual Killifishes, Nibia Berois, María J. Arezo, Rafael O. De Sá

Biology Faculty Publications

Annual fishes are found in both Africa and South America occupying ephemeral ponds that dried seasonally. Neotropical annual fishes are members of the family Rivulidae that consist of both annual and non-annual fishes. Annual species are characterized by a prolonged embryonic development and a relatively short adult life.

Males and females show striking sexual dimorphisms, complex courtship, and mating behaviors. The prolonged embryonic stage has several traits including embryos that are resistant to desiccation and undergo up to three reversible developmental arrests until hatching. These unique developmental adaptations are closely related to the annual fish life cycle and are the …

Sex Ratio Bias And Extinction Risk In An Isolated Population Of Tuatara (Sphenodon Punctatus), Kristine L. Grayson, Nicola J. Mitchell, Joanne M. Monks, Susan N. Keall, Joanna N. Wilson, Nicola J. Nelson

Biology Faculty Publications

Understanding the mechanisms underlying population declines is critical for preventing the extinction of endangered populations. Positive feedbacks can hasten the process of collapse and create an ‘extinction vortex,’ particularly in small, isolated populations. We provide a case study of a male-biased sex ratio creating the conditions for extinction in a natural population of tuatara (Sphenodon punctatus) on North Brother Island in the Cook Strait of New Zealand. We combine data from long term mark-recapture surveys, updated model estimates of hatchling sex ratio, and population viability modeling to measure the impacts of sex ratio skew. Results from the mark-recapture …