By: Brendan Atkins, Category: Science, Date: 27 Mar 2014
Professor Ronn Altig visited the Museum to describe tadpole specimens collected by Dr Jodi Rowley in Vietnam.
Jodi Rowley sent me tadpoles of the Vampire Flying Frog [Rhacophorus vampyrus] and I had never seen a tadpole like that. They are so weird. It has a number of characteristics that no other tadpole in the world has, let me put it that way. It wasn’t just the fangs – there’s other things that we still don’t understand.
Its lower jaw assembly, as far as I can see using a dissecting microscope, seems very different. It’s a very strange animal. I’d be surprised if we don’t also find other oddities about the larval skull (which in tadpoles is cartilage, not bone). I’m sending specimens to a researcher in Argentina who does histological reconstruction. She’ll cut it into sections about 10 microns thick, photograph each section and then the computer will put each of the sections back together, so she can look at the skull and everything more closely in three dimensions.
In general (and there is much variation) a genus of frog will often have tadpoles that are representative of that genus. They’ll vary and so forth, but every once in a while throughout frogs we have these novelties show up. Is vampyrus a complete novelty of its own, or is it the only living representative of a lineage that was novel? It’s likely that vampyrus is a living lineage within the genus Racophorus, all of whose ancestors are not available any more.
The genetics of the frog say it’s nothing special at all. The interesting part is that frogs have tadpoles, frogs have morphology, tadpoles have morphology, but within the genetics of frogs, those two ‘programs’ [for the adult and larva] can operate fairly independently. So there can be a change in the tadpole part of the genes that makes it do something weird and it only affects the tadpole.
While I’m here with Jodi I’m primarily working on stuff she’s collected in Vietnam. Jodi doesn’t just collect adults – she photographs and collects the eggs and tadpoles and sorts them in the field. She also collects a small piece of tissue from the frogs and tadpoles and genetically she can identify them so she knows which tadpole goes with which frog. That means the job I do [describing the tadpoles] can be much more accurate because I’m not having to guess which tadpole goes with which frog. But she doesn’t specialise in tadpole morphology and would like to have this information available.
So I applied for the Geddes Fellowship and that’s why I’m here, to try and work out as much of that stuff from Vietnam as I can. I think by the time I go home, after four weeks, I’ll have eight manuscripts in various states of completion that I can go home and finish. Seven of them have to do with tadpoles and eggs in Vietnam.
To describe the tadpoles, it’s all done with photography, measurements and verbal descriptions. These are known species of frogs whose tadpoles have not yet been described – you can publish a description of a new species of frog without describing the tadpole. (And actually you can do the opposite, name a new frog based on a description of the tadpole only – there’s nothing in the Code that governs such thing to say you can’t, though I don’t know what people would think about that.)
I’m based at Mississippi State University. I retired fourteen years ago but haven’t gotten brave enough to quit! I got tired of the teaching – I enjoyed 28 years of it, but the last two I didn’t. And I suddenly realised I had my 30 years, I was only 59 and I said ‘I’m out of here’, and they said ‘As long as you produce and behave yourself, you can have an office’, so I’m still truckin’.
I don’t get out in the field much anymore – gettin’ too dang old for that regretfully. I’ve been to Vietnam about 20 years ago and it was a great place and I wish I could go back, but I just know I can’t handle the physical side of field work. I have to rely on people like Jodi to send the samples.
Why did I get into frogs and tadpoles? The only thing I can say is when I went from a little farm boy in Central Illinois to the University of Illinois, I went from a country town of 600 to a university of 42,000. I mean, I was pretty amazed! Well I met a fellow there who was a famous herpetologist, [Hobart Smith] (who died in 2013 aged 100), and he kind of took me under his wing. He worked almost exclusively on reptiles and he introduced me to one of his graduate students, Ron Brandon, who worked almost exclusively on salamanders. So I just always seemed to take the opposite: OK, Smith’s got reptiles, Brandon’s got salamanders, I’ll take frogs! When Ron went to Southern Illinois University I went down as his Masters student.
But previous to that, in 1962, I rode one of the first Honda motorcycles that came into central Illinois to the World’s Fair at Seattle [over 3200 kilometres] and was totally blown away – I found out there are areas of the US that are not covered by corn and soya beans! And I said I’ve got to get back here. So I went down to Southern Illinois and got my Masters, then I went to Oregon State University.
On the way out there [to Oregon] (and of course Illinois is quite flat, especially the part where I lived, it’s really flat) well I went up over Tioga Pass and Yellowstone National Park at 9000 feet in August and it was snowing! And I walked out there because I could hear frogs calling and there, at 9000 feet in the snow, I saw tadpoles in the water! And that’s the story I tell that got me into tadpoles.
And the other overriding thing, in anything, I don’t care what it is, I don’t like doing the same thing everybody else does. And almost nobody else is interested in tadpoles, so . . .
I did eventually find out what those tadpoles in the snow were. One of them’s extinct and the other’s almost extinct. The one frog is close to extinction, they‘ve flown over all those high altitude lakes and dropped thousands and thousands of hatching trout, just so people can go out and catch a fish. And a trout can live in a pretty small area of water, so anything a trout can live in, a tadpole’s not going to make it.
And the other thing is this chytrid fungus, which has affected so many species, is messing with them pretty badly. The future’s not looking great for frogs. I don’t keep up with it that much, but there’s some new diseases coming along behind the chytrid fungus, viruses and things, which means there’s likely to be another whole wave of extinctions.
An edited version of this interview was published in Explore 36(1) (2014).