Wednesday, January 25, 2006

Graeme’s Pleistocene megafrog


I didn’t talk much to people today: I spent most of it sat in front of a PC, dealing with over-due email responses and sorting through manuscripts I’m handling for my editing job. Jeff Liston phoned though, and I also caught up briefly with Dave Martill for a catch-up on the British dinosaurs project we’re working on (deadline end of this month… gack). I need not labour the point that a disturbing amount of time is passing without me working on my phd thesis. And then Graeme Elliott came to see me. He saw that I was printing out Pounds et al’s (2006) recently published Nature paper on global lissamphibian extinctions. Make no mistake, frogs and toads are in big trouble, with populations and species disappearing at a disturbing rate.

What does Graeme think about this? He thinks that there should be a giant Pleistocene frog somewhere out there in the fossil record, the size of a Labrador at least and able (theoretically, were these organisms contemporaneous) to eat puppies and small children. Skull Island should harbour relict descendants of such forms, though I doubt they would fare well among giant V. rexes, terrestrial predatory crocodyliforms and truck-sized arthropods. Are there any particularly big fossil frogs? Not really. Aubrey Smith, Marc Jones and Susan Evans have been giving conference presentations on a Cretaceous Madagascan fossil they’re referring to as a ‘hyperossified megafrog’ - I think I detect a hint of hyperbole. It’s the biggest Mesozoic frog yet reported, but even so it was probably not much bigger than, say, Ceratophrys (the extant Horned frog). I doubt if Cenozoic fossil frogs got much bigger than extant forms.

Indeed the biggest frog of all time, so far as we know, is the Goliath frog Conraua goliath (and not Rana goliath as said in some older sources, though Conraua was included in Rana until Nieden separated them in 1908) of Cameroon. Described in 1906, it’s one of six Conraua species, sometimes called the slippery frogs. I don’t have Mark Carwardine’s Guinness Book of Animal Records by my side right now, but I think they get to about 60 cm (with legs outstretched) and over 3 kg. For a frog, that’s big. Of course there’s always the unverified carn-pnay of the New Guinean highlands – a crypto-frog supposedly bigger than C. goliath.

Why aren’t there frogs the size of labradors? I don’t know if it’s been discussed in the literature, but I’ve always liked the idea that lissamphibians are constrained in size by the fact that most of them rely on cutaneous respiration. Bigger lissamphibians, having a small relative surface area, should find it more difficult to respire compared to their small relatives, and this prediction seems to be confirmed by the fact that the biggest lissamphibians (the cryptobranchid salamanders) are aquatic. Surely there’s stuff in the herpetological literature that covers this. Maybe I should check.

The picture above is taken from the University of California's amphibian pages.

Coming soon on this blog site… Why rabbits are just wrong; Birds in crevices; Transatlantic manatees; and Eagle owls take over Britain. For the latest news on Tetrapod Zoology do go here.

Ref - -

Pounds, J. A. Bustamante, M. R., Coloma, L. A., Consuegra, J. A., Fogden, M. P. L., Foster, P. N., La Marca, E., Masters, K. L., Merino-Viteri, A., Puschendorf, R., Ron, S. R., Sánchez-Azofeifa, G. A., Still, C. J. & Young, B. E. 2006. Widespread amphibian extinctions from epidemic disease driven by global warming. Nature 439, 161-167.

9 Comments:

Anonymous Anonymous said...

No i've years searched in literature and other sources about this enigma ,Giant Frogs what really intriges me, the idea of a frog that can swallow a dog!But the biggest i think we're the late PLeistocene Giant from Fiji ,;Platymantis megabotoniviti that could grow large like the C. goliath ,about than 30-34 cm body length ,what got extinct sadly due to human intervention and predation from faunal intruders that didn't belong there,like Bisamrats,mongoose and cats,what harm we have already done does it ever stop!?
ALso very noticeble is Pixycephalus Adspersus that can get more than 26 cm in body length ,from Central Africa,it is recorded at over 2,000 grams ,and maybe the rare CAudiverbera caudiverbera,from Chili also more than 20 cm,..
From a book I have i read about the record Goliath at 112 cm and about 9 pounds ,.but stories of natives tell about larger frogs ,...the same day the frog was caught ,a larger one escaped...so told the catcher..A Cameroon fishermen.
Please let me know more about the Graeme Mega frog,its very interesting,I am a late student Eco-physiology & nature conservation ,after being a military specialist the green world attracts !!!
Keep in touch !
Marc marc-abuys@hotmail.com

9:22 AM  
Anonymous Anonymous said...

hello ,do you have any information about the Carn-Pnag from N.Guinea ? i ve read some material in a book on Amphibians ..or maybe where i can find some,..are there any pictures yet about it,!? Or is it like the European TAtzelwurm a cryptid that maybe doesnt even exist,..
I know large frogs do,and more like we have still about 78 % to discover of land organisms...Ecologists say,....
Ok also o hope to hear from the titel Artikel too,.
Thanks,... Marc
marc-abuys@hotmail.com

9:31 AM  
Blogger Darren Naish said...

Thanks for your comments Marc, much appreciated. The carn-pnay or agak of New Guinea is tremendously obscure and I have very little information on it: it is a cryptid (i.e., reported by local people and unknown from specimens) and apparently there has been one scientific expedition in quest of it. According to Trevor Beebee's 1985 book Frogs & Toads, an academic paper does exist on the subject but I have yet to find the reference (I am presently asking around). Beebee's book also includes the only picture I've ever seen of a carn-pnay, but it's a cartoon showing an immense frog (as big as an elephant) hiding behind trees while exploring scientists walk by. Neither 'carn-pnay' nor 'agak' are mentioned in any of the cryptozoology encyclopedias I have checked, and there is nothing on the web, bar a link to this blog post.

Given the huge number of frog species that continue to be discovered (the number of recognised anurans has increased by over 40% since 1985), it remains possible that a few big species await recognition. In Throwim Way Leg (1998), Tim Flannery discusses a mid-sized, round-bodied New Guinea frog bristling with dark papillae, and if accurate then this description surely refers to an unknown species. A few other frogs, known from eyewitness accounts but not from formally accessioned specimens, have been reported, including an arboreal species from the Cameroons that reportedly has a glowing snout and an unidentified white frog from Rwanda. The carn-pnay is supposed to exceed Conraua in size - though by how much I'm not sure - and while it's conceivable that a particularly huge frog might remain undiscovered in New Guinea, it's unlikely.

So, in the absence of information I'm not sure how seriously we should take the carn-pnay.

12:58 AM  
Anonymous Marc Abuys said...

Thanks for mentioning ,i can look further now on the Carn-Pnay .......So than that makes the legendary Carn-Pnay a cryptic Cryptid ,doesn't it ? Ive heard more from the gigantic Frog of Papua in other books mentioned ,further on television they show something about these Frogs but that 's long ago,at least ten to fifteen years back,..tell me what is your specialty on herpetology,or do you have more groups,..also an intriging Animal is the Large Aquatic Telmatobius culeus,.From Lake Titicaca,Peru, it should be the largest freshwater frog in the world,legs stretched between 50 to 60 cm, It developed a special adaptation physiology to stay permanently under water also in cold periods and it's skin is so widely folded it has more surface of skinparts it can contain more oXygen to protect if from the fact the water holds less oxygen in colder water at high Attitude which allows an aquatic life in cool (10 degrees C) O2-saturated (at 100 mm Hg) waters at high altitude (3812 m). The skin surgace area is increased by pronounced folds and the cutaneous capillaries penetrate to the outer layers of the skin. The erythrocyte volume (394 mu3) is the smallest reported for amphibians .....Its a recordholder on many fronts!!!
i'll look for the Article ,but if you have anything on the mega Frog AGak or the Graeme Mega frog ,or other specialties pelase send me or post a link please..also cartoons you mentioned is fine ,i'll look for some for my coming issue of The Rana ,our field and specilized magazine on Herpetology .
maybe you can write al little piece about it ,..and i'll send you a copy.......
By the way have you heard maybe of the Tatzelwurm,!? A legendary cryptid reptile from Austria ,And Switserland......it's a strange one.
Marc says hii..

5:23 PM  
Anonymous Marc Abuys said...

Thanks for mentioning ,i can look further now on the Carn-Pnay .......So than that makes the legendary Carn-Pnay a cryptic Cryptid ,doesn't it ? Ive heard more from the gigantic Frog of Papua in other books mentioned ,further on television they show something about these Frogs but that 's long ago,at least ten to fifteen years back,..tell me what is your specialty on herpetology,or do you have more groups,..also an intriging Animal is the Large Aquatic Telmatobius culeus,.From Lake Titicaca,Peru, it should be the largest freshwater frog in the world,legs stretched between 50 to 60 cm, It developed a special adaptation physiology to stay permanently under water also in cold periods and it's skin is so widely folded it has more surface of skinparts it can contain more oXygen to protect if from the fact the water holds less oxygen in colder water at high Attitude which allows an aquatic life in cool (10 degrees C) O2-saturated (at 100 mm Hg) waters at high altitude (3812 m). The skin surgace area is increased by pronounced folds and the cutaneous capillaries penetrate to the outer layers of the skin. The erythrocyte volume (394 mu3) is the smallest reported for amphibians .....Its a recordholder on many fronts!!!
i'll look for the Article ,but if you have anything on the mega Frog AGak or the Graeme Mega frog ,or other specialties pelase send me or post a link please..also cartoons you mentioned is fine ,i'll look for some for my coming issue of The Rana ,our field and specilized magazine on Herpetology .
maybe you can write al little piece about it ,..and i'll send you a copy.......
By the way have you heard maybe of the Tatzelwurm,!? A legendary cryptid reptile from Austria ,And Switserland......it's a strange one.
Marc says hii..

5:25 PM  
Anonymous Marc Abuys said...

Further i would like to mention something about the fact that indeed many species ,still awaiting ,or maybe they're not waiting ..but still have to be discovered and some numbers i've recently seen on a Ecological source, are from the Hexapodidae ,from the 1,350,000 known species are probably more than 30 to 33 million species alive !,
and from Amfibians they noted maybe about 27,500 to over 30,000 species from the now ,about 6,000 known...That's an incredible high number but very up-to-date.the sama on the other genera on reptiles they talked about a staggering 40.000 to more than 45,000 species they think probably exist .So i think on the amount of researchers come with new material on new species and genera,there's a good chance to find incredible species of Frogs and salamanders which will surprise us definitely.

5:49 PM  
Anonymous Marc Abuys said...

Further would like to mention something about the fact that indeed many species ,still awaite ,or maybe they're not waiting ..but still have to be discovered and some numbers i've recently seen on a Ecological report, are from the Hexapodidae ,from the 1,350,000 known species are probably more than 30 to 33 million species alive !,
and about Amfibians they noted that about 27,500 to over 30,000 species from the about 6,000 known..exist...That's an incredible high number but very up-to-date.the sama on the other genera on reptiles they talked about a staggering 40.000 to more than 45,000 species they think probably exist .So i think on the amount of researchers come with new material on new species and genera,there's a good chance to find incredible species of Frogs and salamanders which will surprise us definitely. Some Giants will occur but more average kind of species ,that have a limited range or distribution.

6:00 PM  
Blogger Darren Naish said...

Thanks for your messages Marc - I will reply soon; I regret I haven't had time yet. Yes, I am familiar with the tatzelwurm!

10:59 PM  
Anonymous Ecoman said...

Hello Darren ,for quite some time know,i've been curious to know if you have soms more data ,or publications mentioned the Papua Giant Carn Pnay,or some other explanation about this biological enigma what you call the Graeme’s Pleistocene megafrog.its mighty interesting but said that many large and strange snakes are still found ,also monitor lizards but still no Extremely out of Proportions of an Anuran. The fact that Giant Amphibians do occur after the Temnospondyli (Labyrinthodontia) evolved and Anurans came up,from these magnificent creatures...These were about half a ton and like 4 metrs long in that order.

Also im very curious in what you seen or heard on the Megalania Prisca that is often mentioned and reported from both Arnhemland and Queensland...lately also scientist should have encountered this giant monitor from the Pleistocene....

Ill hear from you,

Marc Greets

7:53 PM  

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