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Frog Facts: New Species Has Fangs and Gives Birth to Live Tadpoles!

Limnonectes with tadpoles

Uploaded to Wikipedia Commons by Djoko T. Iskandar, Ben J. Evans, Jimmy A. McGuire

While working at the Bronx Zoo, I had the good fortune to breed Kihansi Spray Toads – an endangered species that gives birth to fully-formed toadlets – and the amazing skin-brooding Surinam Toad. Yet these are but two examples of the amazing diversity of odd frog breeding strategies, none of which resemble what might be called “normal” frog behavior! Among the world’s 6,400+ frog species, we find tadpoles that eat bark, their mother’s eggs and even their father’s skin, along with parents that carry eggs or young in skin pouches, vocal sacs and even stomachs. None, however, were known to give birth to live tadpoles. As you’ll see below, a herpetologist’s extremely lucky catch, at just the right moment, changed that recently – one can only guess at what will come next!

 

Crested Macaque

Uploaded to Wikipedia Commons by Yi Chen

Strange Frog in a Strange Land

The Indonesian island of Sulawesi, located between Borneo and the Philippines, is home to some of the world’s most unique and (to most of us) unexpected animals. From invertebrates to mammals, the island’s fauna is “rule-breaking” and astonishing (take a look at the Sulawesi Black “Ape”, pictured here). So the UC Berkeley biologists working there recently were well-used to surprises. But when a herpetologist grabbed at a frog and came up with a handful of tadpoles as well, he knew that new ground had been broken.

 

Fanged Frogs

The frog in question, Limnonectes larvaepartus, had been collected before, but has only now been recognized as a new species. Endemic to Sulawesi, it belongs to a little-studied group known as the Fanged Frogs. Armed with sharp bones that project from the lower jaw (similar to the odontoids borne by Horned Frogs and African Bullfrogs), male Fanged Frogs battle one another, presumably for mates and territory.

 

Tailed Frog

Uploaded to Wikipedia Commons by Mokele

Internal Fertilization and Live Birth

But where Limnonectes larvaepartus is concerned, peculiar dentition is only the beginning of the story. Following the timely capture of a female in the process of giving birth, it was determined that this new species also employs a new (to us, anyway!) form of reproduction. It is the only frog known to produce live tadpoles rather than eggs or small frogs. What’s more, fertilization is internal – a strategy used by only 8-10 of the world’s 6,455 frog species (including the USA’s Pacific and the Rocky Mountain Tailed Frogs; please see photo). The new species is described in the journal PLOS One (12-31-14, Iskander et al; see link below).

 

This discovery may help herpetologists to understand the evolution of the amazing diversity of Fanged Frogs on Sulawesi and elsewhere in Southeast Asia. Many more than the currently described 62 species are expected to be found, and as with all creatures on Sulawesi, they likely hold wonderful surprises for us.

 

Habitat type

Uploaded to Wikipedia Commons by Killerscene

Natural History of the New Species

We know very little about Limnonectes larvaepartus. There is some speculation that males may guard the tadpoles, but this remains to be confirmed. Females seem to rely upon small forest pools in which to deposit their tadpoles. This may be an attempt to reduce the threat of predation by larger relatives that inhabit nearby streams, but further research is needed.

 

Learning More About Amphibian Breeding Strategies

I can’t seem to stop writing about the amazing breeding strategies of frogs, caecilians and salamanders. Please see the articles below for more on wood-eating tadpoles and others. The article first describing Limnonectes larvaepartus is also linked.

Tree-Dwelling Tadpoles that Feed Upon Bark

Skin-Eating Tadpoles

Novel Reproductive Mode in a New Species of Fanged Frog

 

2 comments

  1. avatar

    We noble humans think we are the only “unique” beings in the universe, but we have only to look on our own planet to see amazing contraditions to our superiority!

    Thanks for sharing these amazing creatures.

    Karen

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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