Friday, April 4, 2014

The Coelacanth has had its day

Who hasn’t wanted to bring an extinct species back into existence? Sure, there are risks, both physical (T. rex and pathogens) and ethical (Neanderthals), and sure, we’re better off without some species (smallpox and mososaurs), but how about the gastric brooding frog and the thylacine and the dodo and so on? Surely the world would be a better – or at least not worse – place if we hadn’t lost them. Enter the de-extinction movement, which seeks to bring extinct critters back to life. It hasn’t happened yet, of course, and it might never happen given not only the risks but the costs and difficulties. Even better than de-extinction – and without any of the ethical baggage – is when things thought to be extinct are found not to be (unextinction?).

Being a fish guy, one of the most inspiring unextinction stories is the discovery of the coelacanth – though to be extinct for more than 60 million years. Found on December 22, 1938, in the bottom of a pile of fish on a trawling ship by the young curator (Marjorie Courtenay-Latimer) of a tiny museum in East London, South Africa, this first specimen was bundled into a cab with the help of a very reluctant cab driver, sketched iconically and the sketch mailed to Professor J.L.B. Smith at nearby Rhodes University. The discovery rocked the scientific world but was less than ideal given the lack of preservative available in East London. Then came the search for another specimen, found only 14 years later in the Comoros. Here the story only gets better, with midnight calls to the Prime Minister of South Africa, a clandestine military evacuation, and an indignant French establishment. And then, in 1998, a second coelacanth species was found in Indonesia in a fish market by a couple on their honeymoon. This one was quickly named by French scientists who hadn’t seen it, in apparent retaliation for the loss of the Comoros specimen. (If these tidbits intrigue you, read the full coelocanth story in A Fish Caught in Time.)

Marjorie Courtenay Latimer and the famous sketch that started it all.
De-extinction the way it should be – unextinction! This story had always been one of my favorites and so I had long been excited to see a coelacanth – if only in a big vat of preservative. However, few coelacanths are in North American museums, partly because of the monopoly the French exerted for years after the Comoros scoop by the Brits. So I didn’t get to see one until I went to France, where every Podunk museum and aquarium in every tiny town seems to have one – I saw mine in Biarritz. My daughter even got to see it, although I am not sure at the age of one she had much appreciation for its scientific significance. Truly an inspiring moment – although some day I would love to see one in the wild (probably harder to see than nearly anything else).

The Biarritz coelacanth - a treat for me and for Aspen!
Of course, coelacanths remain very rare, perhaps forever at risk of re-extinction, something we should surely seek to prevent. Indeed, the goal of preserving truly unique species is gaining steam in conservation biology. The basic idea is that many species are likely at risk of extinction and we need some sort of criterion for deciding which to preserve. One criterion that has been put forth is phylogenetic distinctiveness. That is, the species that warrant the most protection are those that represent the last remaining bits of long isolated branches of the evolutionary tree – lose that last species and forever lose a big chunk of the history of life. A recent incarnation of this idea is EDGE (evolutionarily distinct globally endangered), which seeks to prioritize species conservation based on a joint consideration of phylogenetic distinctiveness and degree of endangerment. So far so good; finally conservation biologists are fully using evolutionary criteria for species conservation! Something all evolutionary biologists can get behind – or is it?

A few weeks ago, I was in College Station, at Texas A&M University, as one of the invited speakers for the Ecological Integration Symposium organized by graduate students (my host was Emily Rose). My talk was on ecological speciation, David Reznick spoke on eco-evolutionary dynamics, Brian Bowen discussed marine speciation, and Tom Lovejoy gave an overview of global climate change effects. At the end of our plenary session, we had a panel discussion. At first, the four of us thought it might be awkward as our talks had been on very different things – but we quickly converged on a topic to which we could all provide perspectives: What, precisely, should we be conserving? A large part of the discussion focused on the importance of preserving not only species but also intra-specific variation, but we also discussed which species should be preserved. At one point, I went through the above rationale about phylogenetic distinctiveness being an important criterion and then Brian grabbed the mic out of my hand.

“THE COELACANTH HAS HAD ITS DAY” was the first sentence out of his mouth. He then went on to describe how species come and go all the time and those old rare relicts just hanging on (coelacanths, tuataras) are probably not long for this world (extinctive?) regardless of human influence – so perhaps we shouldn’t bother. Instead, we should focus our efforts on groups that are rapidly diversifying – African cichlids was his prime example – as they are the future of biodiversity. Ok, sure, I like cichlids as much as (probably more than) the average person, but let the coelacanth go? Heresy. Fear. Fire. Foes. Right then and there I excommunicated him from the pantheon of evolutionary biologists, revoked his citizenship in a compassionate humanity, unfriended him on Facebook, and started a smear campaign to discredit him.

Me and Brian Bowen, the most dangerous man alive - for coelacanths anyway. (Photo by Melissa Giresi.)
On sober (actually just the opposite) subsequent refection, however, I began to question my reaction. Try this thought experiment. How many cichlid species is the coelacanth worth? I think we can surely say at least one. Taking inspiration from Phil Pister’s “species in a bucket”, if I had all of the world’s Pseudocrenilabrus multicolor in a bucket in my left hand and all the world’s coelacanths in a bucket in my right hand, I would probably saw through my left wrist before dropping the bucket in my right. (I might hesitate longer if the hands were reversed.) I would probably decide the same for 10 cichlids or maybe a hundred but what about a thousand or ten thousand – what if it was the entire cichlid fauna of Lake Tanganika or Malawi or Victoria? By the EDGE perspective, I expect that I would save the coelacanth. By the de-extinction perspective, I would probably do the same (it would be much harder to re-evolve the coelacanth than start a new radiation of cichlids – after all, they do it all over the place). But by the Bowen perspective, I would clearly drop the coelacanth without a second thought. And at some level, I see the point. Coelacanths aren’t going to give us anything new. At best, they will still be around a million years in the future looking pretty much the same. The cichlids, however, will likely produce many new species in that time. The future of biodiversity is perhaps better off with the cichlids than coelacanths.

Fortunately, I am not a manager and don’t have to make such decisions, because the truth is I want both cichlids and coelacanths! But perhaps I could do without ticks and chiggers and dengue and AIDS and TB and definitely poison ivy.

An amazing giant isopod in the Texas A and M invertebrate collection. (Photo by Melissa Giresi.)

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