Frogs of Victoria: A Guide to Identification, Ecology and Conservation

By Nick Clemann and Michael Swan

Amphibians are one of the world’s most rapidly declining fauna groups. In an era of devastating climate change, habitat destruction and irreplaceable loss of biological diversity, it has never been more important to have effective resources for identifying and managing wildlife.

Tapping into the deep knowledge of the best frog experts in south-eastern Australia, Frogs of Victoria not only provides the tools to identify Victorian frogs – including keys, photographs and comparative information on similar species – it also presents detailed information on their biology, habitats, status and threats. Importantly, the authors also detail the urgent actions required to prevent further loss of amphibian diversity in Victoria.

Including stunning images from some of Australia’s finest wildlife photographers, Frogs of Victoria is an authoritative resource for ecologists, land managers, conservationists and all who are fascinated by frogs.

• Language: English
• Publisher: CSIRO PUBLISHING
• Release date: Jul 3, 2023
• ISBN: 9781486313839

Nick Clemann

Nick Clemann has been leading programs on threatened wildlife throughout south-eastern Australia for 25 years. He advises government on threatened species research, management, policy and scientific permits. He works for Zoos Victoria and holds an honorary position with Museums Victoria.

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© Nick Clemann and Michael Swan 2023

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Nick Clemann and Michael Swan assert their right to be known as the authors of this work.

A catalogue record for this book is available from the National Library of Australia.

ISBN: 9781486313815 (pbk)

ISBN: 9781486313822 (epdf)

ISBN: 9781486313839 (epub)

How to cite:

Clemann N, Swan M (2023) Frogs of Victoria: A Guide to Identification, Ecology and Conservation. CSIRO Publishing, Melbourne.

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Front cover: (top, left to right) Dendy’s Toadlet (Pseudophryne dendyi) (photo by Peter Robertson), Spotted Tree Frog (Litoria spenceri) (photo by M. G. Swan), Southern Brown Tree Frog (Litoria ewingii) tadpole (photo by M. G. Swan), Victorian Smooth Froglet (Geocrinia victoriana) (photo by Nick Clemann); (bottom) Baw Baw Frog (Philoria frosti) (photo by Damian Goodall)

Back cover: (left to right) Plains Brown Tree Frog (Litoria paraewingi) (photo by M. G. Swan), Common Froglet (Crinia signifera) (photo by Marion Anstis), Southern Giant Burrowing Frog (Heleioporus australiacus flavopunctatus) (photo by Nick Clemann)

Edited by Brooke Clark

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Foreword

What a wonderful bird the frog are!

When he hop he fly almost.

When he stand he sit almost;

He ain’t got no sense hardly;

He ain’t got no tail hardly either.

When he sit, he sit on what he ain’t got almost.

Anonymous

A bird? Perhaps not. But wonderful: absolutely! I can’t agree that he got no sense hardly, but other than that, the unknown author of this gem of whimsy has managed to nail the essence of frogginess quite successfully. If you were composing it today the frog might have to be ‘it’ instead of ‘he’, though that would certainly erode the folksy charm of the piece.

The focus is sharply on the frog’s architecture, notably the absence of a tail, a rare condition among tetrapods (though we and the other apes share it). The technical name of the group to which frogs belong highlights it: Anura (Greek an, without; oura, tail). The frog backbone is short (only nine vertebrae) and rigid, and typically the hindlegs are longer and more heavily muscled than the forelegs. Hence the frog’s ‘stance’ (he sit almost), with the front end elevated and the rear end on the ground. When he hop he fly almost, by pushing off from the ground using his powerful thigh musculature (that’s the bit that some people – emphatically not me – eat). But in fact he doesn’t always hop; in many species the usual gait is walking or crawling. Some are also proficient climbers or burrowers.

Structurally, then, the frog can lay claim to being ‘among the weirdest of tetrapods’. But if you’re not enthralled with frog anatomy it’s quite likely that other elements of frogdom might shape your thinking. Size, for one thing: frogs are small; the biggest species in the world measures a little over 30 cm and weighs a little over 3 kg. (At the other end of the scale, a recently described midget frog species in Madagascar is less than 10 mm in length.) Coupled with their naked skin and lack of formidable teeth or claws, this makes frogs seem humble and vulnerable, though many produce skin venoms that may be quite potent. And again, frogs are visually inconspicuous, hiding by day, active at night, and rarely revealing their presence except by being noisy when breeding.

But the most significant element of the vulnerability of frogs stems from their dependence on moist terrestrial niches and non-saline waters to sustain the stages of their two-part life cycles. Whatever changes might be taking place in earth, air or water will impinge on frogs in their egg, tadpole and adult stages. Hence a world that has become dominated by a large animal that is addicted to introducing exotic species, clearing forests, farming, mining, damming rivers, heating the atmosphere, over-consuming resources and producing unimaginable amounts of waste of an unimaginable variety … is precisely what frogs don’t need. And they particularly don’t need the human-driven global spread of a fatal and presently untreatable disease.

This book is successor to the Frogwatch Field Guide to Victorian Frogs, which was published in 1991, co-authored by three experts with an immense combined body of frog wisdom; their book is still worth consulting. But beware: several of the family, genus and species names have now changed, and there have turned out to be some species in the state whose presence was not then known. Surely more significantly, however, frog population declines and the need for active conservation measures receive only a brief passing mention; just three species are described as endangered or declining. This is not a criticism of the authors; I don’t doubt that it fairly represents the situation at the time. The infectious and lethal frog disease chytridiomycosis doesn’t feature at all – why? Because although the existence of the causative agent (the fungus Batrachochytrium dendrobatidis) was known by then, the threat that it represented to frog populations and its extensive and expanding distribution in Victoria (and elsewhere) had not yet been generally recognised.

The publication of an up-to-date Victorian frog book by two authors whose livings and passions have been frog-centred for decades is to be welcomed and celebrated. But at the same time, they would be deeply disappointed if their book did not generate widespread concern for the future of the state’s frog fauna: it is in serious trouble. When I first became acquainted with it in the early 1960s it was commonplace to be able to listen to a springtime froggy chorus not far from Melbourne for a few minutes and identify the calls of at least six species; the declines in both the diversity and the abundance of frogs since then are stark and unquestionable.

The keys, descriptions and excellent photographs of frogs will certainly enable you to identify Victoria’s frogs and to learn more about them, but the book wants to do much more than that. There are photos not only of the frogs, but also of their habitats, including instances of the kinds of damage that those habitats suffer. Without habitats there would be no frogs, and if we want to have frogs it’s their habitats that we need to understand and protect. Save the habitat! is of course the conservationist’s repeated cry, but this book does more than just reiterate it. The current Victorian and Commonwealth regulations and legislation that apply to frogs are summarised; more importantly, the major changes and practices that threaten frogs are described and listed. For each identified threat, furthermore, measures for its mitigation are specifically detailed. To everything there is a season, and to every threat there is a means of mitigation. What are needed are the understanding, the investment and – first and foremost – the will, to employ them.

If you’re interested in or fond of frogs, then I’m sure I don’t need to recommend this book to you; you’ll buy it and dive enthusiastically into it and probably skip this foreword anyway. But if frogs aren’t in your top 10 then I think your need for this book and the value to you in studying it remain paramount. Why? For the very reason that the habitat requirements of frogs encompass pretty much all of the range of terrestrial and aquatic ecosystems in Victoria (or anywhere else). If you meet the needs of frogs, you will be meeting the needs of biodiversity at large. Is that an ambitious enough goal for you?

Angus Martin

Contents

Foreword

Acknowledgements

Introduction

1: Naming and classifying frogs

2: Biology of frogs

3: The amphibian fauna of Victoria

4: Victorian zoogeographic regions and ecosystems, and their frogs

5: Conservation of Victorian frogs

6: Victorian amphibians

Family: Limnodynastidae

Family: Myobatrachidae

Family: Pelodryadidae

Family: Salamandridae

Appendix 1: Wildlife legislation and regulations

Appendix 2: Frogs Victoria

Glossary

Selected bibliography

Index of common names

Index of scientific names

Acknowledgements

We dedicate this book to those herpetologists who not only laid the modern foundations of our understanding of the frogs of Victoria, and share their knowledge generously, but also gave us the information, perspective and wisdom that underpin our fight to conserve Victorian frogs: Murray Littlejohn, Angus Martin, Peter Rawlinson, Graeme Watson and Peter Robertson.

Angus Martin, as well as being a prominent contributor to the most productive era of research on Victorian frogs, exemplifies the finest characteristics of science communicator and educator; we are humbled that he was willing to write the foreword for this book.

As well as the scientific literature, we necessarily relied on existing guides to Australian frogs, and, while our sources were many, those of particular value in the preparation of this book were the works of Hero et al. (1991), Barker et al. (1995), Cogger (2014) and Anstis (2013; the second edition was published in 2019). We are grateful to the authors of these books and suggest that no frog-lover’s library is complete without them. We have intentionally structured this book along the lines of Reptiles of Victoria: A Guide to Identification and Ecology by Peter Robertson and A John Coventry (2019); reptiles and frogs are often considered collectively (as ‘herpetofauna’), and we hope our book is a worthy companion to Peter and John’s book.

We are indebted to Murray Littlejohn, Angus Martin, Peter Robertson and Graeme Watson for sharing information, publications, data, field notes, insights, interpretation and wisdom from their studies of the frogs covered in this book.

Passionate and dedicated people are working hard to improve our understanding of frogs in south-eastern Australia, to stop declines, and to promote recovery. They have been generous with their time and knowledge, provided beautiful photographs, and helped to ensure that the latest and most accurate information on each species is included, that the conservation information is accurate, and that the mitigation guides reflect the best available knowledge from those on the frontline of frog conservation in south-eastern Australia. Nick Clemann thanks: Kirstin Abley, Marion Anstis, Zak Atkins, Rohan Bilney, Phoebe Burns, Renee Catullo, Craig Cleeland, Damien Cook, Vanessa Craigie, Angela Duffy, Rena Gaborov, Deon Gilbert, Damian Goodall, Paul Gullan, Geoff Heard, Dave Hunter, Scott Keogh, Melanie Lancaster, Murray Littlejohn, Angus Martin, Peter Menkhorst, Garry Peterson, Peter Robertson, Michael Scroggie, Glenn Shea, Arn Tolsma, Danielle Wallace, Graeme Watson and Matt West. Nick is especially grateful to Angus Martin and Peter Robertson for labouring through the entire manuscript; their herculean efforts and patient honing of the text resulted in marked improvements. Michael Scroggie provided a helpful review of the dichotomous keys. Michael Swan thanks: Marion Anstis, Jon Birkett, Kwai Chang, Matt Clancy, Greg Clarke, Louise Durkin, Adam Elliot, Greg Fyfe, Harry Hines, Mike Mahony, Stephen Mahony, Charlie Parker, Greg Parker, Mahalia Booth-Remmers, Marcus Whitby and Steve K Wilson. We thank Rachael Hammond for assistance with images.

Paul Gullan (Viridans Biological Databases; www.viridans.com) produced descriptions of Victorian ecosystems that we believe are the best available for characterising the habitats of Victorian fauna. We have followed the example of Peter Robertson and John Coventry for their book on Victorian reptiles by using the Viridans descriptions and maps, and some images. We thank Paul for generously allowing us to do so.

Most of the data for the distribution map for each species were sourced from Viridans and the Victorian Biodiversity Atlas. We thank Paul Gullan from Viridans, and Bev Yen and Mel Hardie of the Victorian Department of Environment, Land, Water and Planning, for providing access to this data. All maps were generated by Viridans geographic software. Peter Robertson led the preparation of the distribution map for each species.

Despite considerable effort, we have not been able to identify the person who took the photograph of Murray Littlejohn in the field (page 12). If this person, or others knowing of this person, can identify the photographer, please contact Nick Clemann so that full acknowledgement can be given in the future.

We thank Eloise Moir-Ford, Mark Hamilton and Tracey Kudis at CSIRO Publishing for support and guidance during the preparation of this book, and consultant editor Brooke Clark for guidance during the final editing phase.

Nick Clemann is thankful for the friendship, support and wise counsel during trying times provided by Phoebe Burns, Zak Atkins and Peter Robertson, and is ever humbled by the support, wisdom and friendship of Angus Martin and Murray Littlejohn.

Mike Swan is particularly grateful to Bernie O’Keefe for his companionship and support over many trips to find and photograph Victoria’s frogs. The ongoing support from his wife Stephanie and family has allowed him to maintain his herpetological endeavours.

Introduction

Vertebrates (animals with backbones) fall into five distinct groups known as classes. One class, Mammalia, contains mammals: endothermic (warm-blooded) animals with hair or fur, which suckle their young and mostly don’t lay eggs (the egg-laying exceptions being the monotremes: platypus and echidna). The class Aves, birds, is an endothermic group defined by their possession of feathers; they reproduce by laying and incubating shelled eggs. Mammals and birds are endothermic vertebrates, and the remaining classes are ectothermic (often called ‘cold-blooded’, although the blood of many ectotherms can be warmer than endotherm blood at times); this means that the body temperature of animals in these groups is mostly determined by external factors and the animal’s behaviour. The class Reptilia (reptiles) demonstrates this well; in temperate areas like Victoria a reptile’s body temperature can be low at night or in winter, matching the temperature of its surroundings, but much higher if the reptile basks in the sun on cool days. Reptiles have scaly skin and may lay shelled eggs or give birth to ‘live’ young. Pisces (fish) comprise a class of aquatic animals with fins, not limbs, with bodies usually covered in scales, and mostly reproducing by laying eggs.

This book focuses on the members of a fifth class – Amphibia, or amphibians – that occur in the state of Victoria. Amphibians lay unshelled eggs, usually in water or moist microhabitats, and their early development occurs mostly in the water. Adults have ‘naked’ skin (i.e. without fur, feathers or scales) and are typically found on land in moist habitats.

The previous field guide to Victorian frogs, Frogwatch Field Guide to Victorian Frogs (Hero, Littlejohn and Marantelli 1991), was published 30 years ago. Prior to that, several authors published checklists of the state’s amphibian fauna, and two authors in particular, Murray Littlejohn and Angus Martin, published keys to some of the frogs, frog calls, tadpoles and eggs of Victorian frogs (these publications are listed in the bibliography). Since the publication of the Frogwatch book, additional species have been discovered in the state, some species have been ‘split’ into more than one species, knowledge of species’ ecology and distributions has improved, and – sadly – concerns about frog declines and disappearances that were just starting to be discussed 30 years ago have been confirmed, and the status of many species has worsened.

Hence the time is right for a new guide to the frogs of Victoria. And because amphibians are one of the most rapidly declining faunal groups throughout much of the world, this book emphasises the declines of Victorian frogs, the known or probable causes of those declines, and what must happen if we are not to lose more populations, and ultimately species, of Victorian frogs.

Almost half of Victoria’s frog fauna is listed as threatened. One species has probably already been lost from the state, and others are on trajectories that, if not arrested, will also result in loss. It can be difficult to interpret rates of loss; some people believe that if a species has declined for several decades, yet is not extinct, we need not worry. But the reality is that if a species declines from common to rare (or extinct) in mere decades, or even a century or two, those losses are almost certainly ‘unnatural’, and they should cause real concern, especially when they are part of a clear pattern of accelerating loss of biological diversity around the world. We hope that one function of this book will be to improve awareness and understanding of the processes that can and do lead to human-caused extinction.

Before disease wiped out most populations in the High Country of south-eastern Australia, the Alpine Tree Frog Litoria verreauxii alpina was common and abundant in the higher elevations of this region. Photograph: Matthew West

We have tried to use conspicuous external characteristics of frogs to provide the information necessary to identify species. We use some technical jargon (such as dorsal surface, ventral surface, tubercles, tympanum) because of its greater precision. A glossary of such terms is provided in the back of this book. We use both common and scientific names somewhat interchangeably throughout the text; we have tried to use both at the first mention of a species in a chapter, and subsequently sometimes use common names when we are confident they will not cause any confusion. However, in each species’ profile we have stuck with scientific names to allow a clinical consideration of each species relative to others. Although many people find scientific names daunting, using them avoids the confusion that can arise due to some species having two or more common names (such as Limnodynastes dumerilii, which is variously known as the Pobblebonk, Banjo Frog or Bullfrog). We encourage readers to become comfortable with using scientific names to avoid confusion in conversations about these species.

Three species, Limnodynastes dumerilii, Heleioporus australiacus and Litoria verreauxii, have recognised subspecies – five (three of which occur in Victoria) for the former, and two each for the other species, although only the subspecies H. australiacus flavopunctatus occurs in Victoria. We have provided a full profile for the subspecies Alpine Tree Frog L. verreauxii alpina but not for the three Victorian subspecies of L. dumerilii. We have elected to do this because, other than distribution, body pattern and toe webbing, the subspecies of L. dumerilii are thought to be mostly similar in their biology and ecology; in contrast, L. v. alpina occupies (or once occupied!) a distinctive high elevation niche, is morphologically distinct, and has undergone precipitous declines that seem not to have happened, or at least not as severely, in the lowland form, L. v. verreauxii, in Victoria.

Eggs and tadpoles

The number of published guides to Australian frogs greatly exceeds the number dedicated to eggs and tadpoles (larvae), even though these stages are obviously as important as the adult stage. There are several reasons for this: when describing the tadpoles of the Melbourne area, Martin (1965) noted that minute examination of the mouthparts of tadpoles is often necessary for definitive identification. This is impractical for most casual field observers; it necessitates capturing the tadpole, which can injure it; and the eggs and tadpoles of most species, being aquatic, need to be removed from the water to confirm identification (or to have their nests disturbed, in the case of terrestrial breeders) – activities that can damage habitats and spread pathogens, in particular the Amphibian Chytrid Fungus Batrachochytrium dendrobatidis. Adult frogs are easier than eggs and tadpoles to identify via their calls and physical attributes, and these identification features are easier for an author to describe and illustrate with photographs.

Eggs of the Southern Brown Tree Frog Litoria ewingii contained in clear jelly masses attached to stems of vegetation just below the water surface in a small, artificial pool in South Gippsland. Photograph: Nick Clemann

Therefore, we provide only brief notes on eggs and tadpoles. Exhaustive and beautifully illustrated coverage of Australian frogs’ life history stages is provided in the books by Sydney biologist Marion Anstis, which are essential and uniquely valuable references (see bibliography).

We have included dichotomous keys to aid in the identification of adult frogs; these are best used in combination with the distribution maps, photographs and the similar species sections in each species’ profile. Each profile starts with the most widely used (in Victoria) common name and alternative common names for the species, as well as the scientific name and a list of synonyms (previously used scientific names). The features most helpful in distinguishing a species from others are highlighted with bold text. The sizes given are for mature adult males and females; they are not necessarily the maximum size recorded for a species. The similar species section lists the simplest and most obvious features of the frog that allow it to be distinguished from similar species. Characteristics of the eggs and some features of a fully grown tadpole are given: its overall length, its approximate body shape when viewed from above, the relationship between the width and depth of its abdomen, and its dorsal