Ventastega curonica

From Science News, a newly described fossil gives evidence of the transition from fish to land-dwelling tetrapods. This is Ventastega curonica, from the late Devonian (365 million years ago) of Latvia, in a recent article in the journal Nature. It's the most primitive Devonian tetrapod, and is intermediate transitional form between Tiktaalik (our favorite early tetrapod) and the later Devonian tetrapods like Acanthostega and Ichthyostega. So I guess it's a fishomander, of sorts?

Alas! One more missing link means two more gaps in the fossil record!

Anyway, to stay on topic, here is the illustration being shown on all the news sites:

Illustration by Philip Renne - click for big

He looks so happy! I had to piece this together since most of the news sites are showing a cropped version sans the bottom-dwelling Bothriolepis in the background, and the only full-version I could find has poor resolution. And Philip Renne doesn't seem to have a website, unless all the media sites are mispelling his name, in which case, Philip, I appologize for my lack of link.

Anyway, I like the painting itself. It's colorful, has a nice balance, looks like it may have been designed for a book cover. But we're missing the most important part of the animal. The innovations of Ventastega are in its legs, and all we get to see here is the big smiley head! Man, that reflection on the eyeball is nice, though. And the angle is so dynamic; I feel like I'm right there in the water with him!

Here's an illustration from Devonian Times showing the nearly complete braincase, shoulder girdle, and partial pelvis:

Illustration by Dennis C. Murphy

Maybe the reason the illustrations don't show details of the foot is we don't have them represented by fossils.

I'd never browsed Devonian Times before; their illustrations have a lovely consistency: black sillouette with red bones. Check out the pages for Tiktaalik, Ventastega, Ichthyostega, and Acanthostega. The site makes it really easy to compare fossil forms. Though I would have put them in chronological and not alphabetical order.

I'm going to try to track down the full Nature article at the library this weekend, so hopefully another update on Ventastega will follow.

Frogamander vs. Crocoduck!

Allow me to rant for a moment. I love listening to science podcasts, especially ones focusing on skepticism, but there have been a couple of irritating mistakes in the last week. It's also possible I'm getting uptight over nothing and being the evolutionist equivalent of the dreaded Grammar Nazi, but anyway...

The first offense was on the May 7 episode (#146) of the "Skeptic's Guide to the Universe," in which host Steven Novella was discussing transitional fossils and mentioned Confusciusornis, one of the feathered dinosaurs of China, referring to it as "a beautiful half-reptile/half-bird." He then made it much worse by reinforcing his idea with the phrase "it really is LITERALLY half-bird and half-reptile." I was irritated, but after some calming tea, I eventually got over it.

But then today I was catching up on "Skepticality," (episode #078) and host Swoopy, in referring to the fossil amphibian Gerobatrachus hottoni said the following:

"...and in Texas, a part-frog/part-salamander is the only fossil found to shed new light on how amphibians evolved into two separate species."

First of all, the fossil represents a possible common ancestor of frogs and salamanders, not some sort of frogamander hybrid, and second of all... two separate species? Living amphibians include three orders: Salientia (frogs and toads), Caudata (salamanders), and Gymnophiona (caecilians), each of which contain many, many, species. Picky? Maybe. This could just be an example of a poorly-phrased remark, and I'm sure Swoopy knew what she meant to say, but there's a point to my rant, so stay with me here.

At least they got it right on the notes section of their website for the episode:

"Just this week, the discovery of the 300-million year old Gerobatrachus hottoni ("Hotton's elder frog") confirmed the previously contentious inference that modern frogs and salamanders evolved from one group of ancient primitive amphibians. The dispute arose because of a lack of transitional forms; but, like so many "missing links," this newly discovered fossil sealed the gap."

If we want people to accept evolution, they have to understand it. We must avoid this confusing language! The missing link between A and B is not "half-A/half-B"; that's not how evolution works! And saying it that way is misleading and confusing and yet... oh, so common.

It's no wonder the Kirk Camerons out there are saying fossil evidence for evolution would have to include something like the Crocoduck:

...

Well, then.

To anyone who has studied and understands evolution, this is, of course, ridiculous. But look at it from the point of view of someone without that education and imagine hearing a news report about a frogamander or dinobird and it becomes clearer how people can become confused and decide to discard the idea of evolution entirely.

Bonus reconstruction of Gerobatrachus hottoni! (From the NGS article)

(awesome)

Even the National Geographic article (linked above) calls the creature a "Frog-amander," and comparative biologist Jason Anderson said of it:

"It had an overall amphibian gestalt...you know, kind of a froggy salamander-y sort of look... so it's kind of a frogamander, if you will."

But he also remarked:

"It pretty convincingly settles the question [that the] frog and salamander shared origins from the same fossil group."

Evolution of course predicts the existence of just such a fossil, but it's so important to keep in mind that a common ancestor of A and B won't necessarily look like an A/B hybrid. Take our common ancestor with chimpanzees, which was most certainly more chimp-like than human-like. We can't accidentally lead people to think that evolution occurs in a manner I once heard referred to as "Pokemon style evolution" in which individual organisms just kind of morph into something else.

It also reminds me of the Nickelodeon cartoon "Avatar: The Last Airbender," in which every animal species is a combination of two or three other things. Platypus bears. Saber-tooth moose lions. Lemur-bats. Rhino-lizards. In fact, the characters became confused upon finding out that the Earth King owned a bear.

Katara: The King is throwing a party at the palace tonight for his pet bear.

Aang: Don't you mean platypus bear?

Katara: No, it just says, 'bear'.

Sokka: Certainly you mean his pet skunk bear?

Toph: Or his armadillo bear?

Aang: Gopher bear?

Katara: Just, 'bear'.

(short pause)

Toph: This place is weird.

So unless we're talking about actual hybrids like ligers and camas (so cute), let's leave our half-and-half animals in the land of fantasy and talk about a reality of missing links and shared ancestors. It's actually much more interesting that way, anyway.

Although...
(sabertooth moose lion picture courtesy of AvatarSpirit.net)