A new species of Acanthocephala (shameless self-promotion!)

My first paper for 2013 is out. If you’re interested in learning about a new species of Acanthocephala from fish, then this is the paper for you.

Weaver HJ and Smales LR (2013) Filisoma filiformis n. sp. (Echinorhynchida: Cavisomidae), a New Species of Acanthocephala from Kyphosus spp. (Perciformes: Kyphosidae) from the South Pacific, and a Key to the Genus Filisoma. Comparative Parasitology 80, 33 – 38.

Find it here: http://www.bioone.org/doi/full/10.1654/4571.1 If you can’t access it, let me know by leaving a comment and I can email it to you.

Here’s the abstract: 

“We describe a new species of acanthocephalan from the reef fish Kyphosus bigibbus Lacepede, Kyphosus sydneyanus (Gunther) and Kyphosus vaigiensis (Quoy and Gaimardi)  from Heron Island, Queensland; Ningaloo Reef, Western Australia; and Moorea, French Polynesia, respectively. Filisoma filiformis n. sp. is differentiated primarily from other species by its long, slender proboscis, with 16–18 longitudinal rows of 42–48 hooks. The wide distribution and multiple host species of F. filiformis suggest that it could be found in other localities around the Indo-Pacific region where kyphosid fish occur. The differing patterns of host range and geographic distribution within the genus Filisoma are discussed.”

 

It’s been so long since I posted last. But my current project is nearly finished, so hopefully the blogging can recommence soon.

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Taxonomy goings-on.

Perhaps as a taxonomist, I don’t get terribly excited about new species in the same way that the general public does. I do love the satisfaction of discovering and describing something new, but I have not yet named a species after a famous person (only my Honours supervisor, who thought having a parasite named after him was a rather dubious honour), or found anything exceptional-looking. But, this week, I’ve found newly described species who are both those things. And I also found some other extra-interesting bits.

David Attenborough’s spider

P. attenboroughi (image via Museum WA)

Via the BBC News, I learned that taxonomists from the Queensland Museum and the Museum of Western Australia have described a new species of goblin spider and named it after Sir David Attenborough. It’s called Prethopalpus attenboroughi, lives in a very small island off northern Queensland, and is less than 2mm long. I’d be far too timid to name something so tiny after someone so great, but maybe there’s an irony there that I’m missing.

The genus Homo gets larger

Taxonomy papers rarely get published in Nature. So I won’t begrudge Maeve Leakey et al. for having the audacity to submit a species description to said journal, because it’s on a new species of Homo. Fossils examined suggest that there was more than just H. erectus and H. habilis roaming around Africa about 2 million years ago. NewScientist has a nice summary for those who can’t get through the Nature paywall. Homo rudolfensis was found in the 1970s and initially considered to be a morphological anomaly and was disregarded. More recent discoveries of similarly-shaped skulls enabled the comparison with the original and the hypothesis that they were anomalus H. habilis was rejected, reinstating H. rudolfensis as a species. Nice.

New caecilian looks like a penis…

…well, it does. I quote a tweet I got from Science Mag: “The penis-snake is an amphibian![link to MongaBay.com]”. A new species of caecilian, Atretochoana eiselti, was discovered in Brazil last year, during the earthworks for a new dam. It’s quite large, around 75cm long (twice the size of your usual, garden-variety caecilian), and, it looks fairly phallic. Most unfortunate.

Atretochoana eiselti (photo by Matt Roper, via MongaBay)

This photo of A. eieslti is necessary for context. Same credit as above.

Want to name a new species?

All this could be yours, via irisauction.com

Conservation scientists in South Africa have found a new species of iris. Not knowing what to name it, they have set up an online auction, to let the highest bidder have a crack at it instead. Check it out at the NewScientist website. Proceeds from the auction will go to the Overberg Lowlands Conservation Trust, which includes looking after the critically endangered habitats where the iris lives. I think it’s a nice way of generating some interest in taxonomy and species discovery, and also generating some funding for research and conservation at the same time. Get your thinking caps on, and your wallets out. When I looked, the auction was at 1100 pounds sterling (I don’t have the little wiggly pounds sign on my Australian computer).

So there you have it – some highlights of taxonomy from the past week. The beauty of taxonomy is that you never know what you might find!

Q: When is a species not a species?

A: When it’s a subspecies. While there are many other potential answers to the question I posed, this is the answer I’m going to explore today.

As a taxonomist, I got quite upset yesterday by the many news outlets describing Lonesome George’s death as “the end of a species”. Because it wasn’t and it is not correct to say so. This isn’t really surprising though, given that sub-editors who write headlines on science articles often aren’t fussed with accuracy. Lonesome George was a particular subspecies of Galapagos tortoise (Chelonoidis nigra abingdonii (Gunther, 1877)). While it was almost certainly the end of a subspecies, the species proper will continue as long as there are Galapagos tortoises to propagate it.

Firstly, the reason why Lonesome George was (is?) important is more to do with history, than anything that George himself had to offer. The Galapagos tortoises, Chelonoidis nigra (Quoy and Gaimard, 1824), as a group, helped Charles Darwin figure out the theory of natural selection. They are fairly important creatures from that point of view. Put very simply, Darwin noticed that the tortoises on different islands of the Galapagos group had distinctly different physical characteristics (traits). But as they must have come from a common ancestor or geographical place, how did these changes happen?

When can we have a subspecies?

We know now that evolution is a continuous process, and we apply artificial dividers to designate species that are all, really, in a state of flux. New species are the result of different traits being selected for via breeding, over a very long time (or not, if the organism reproduces quickly). As generations of tortoises are born with particular traits, their overall appearance changes and they begin to look less like their ancestors and more like their own version. When they are deemed to be different enough, they are designated as their own species. But it’s the intermediate part that gets a bit weird, and has been subject to a range of controversy over the years. The arguing about species has resulted in two camps of taxonomists: the ‘lumpers’, who don’t like subspecies and prefer to bunch all together under species level regardless of population variation; and the ‘splitters’, who do the opposite of the lumpers.

A subspecies is a valid form of taxonomy. It is the name given to a species that has two or more discernible versions (‘races’) but that aren’t morphologically or genetically distinct enough to warrant separate species status. Often subspecies are the result of geographical boundaries, for example the water between all the Galapagos islands. There can never be one subspecies though. It’s either one species, or two or more subspecies. There is no real limit to the number of subspecies that can be recognised, as long as there is enough valid evidence to support the designation (Mallet 2001). Modern molecular techniques can reveal a new level of difference between races of a species, and is a major driver in the increase in species complexes (or often called cryptic species) being discovered.

The tortoise case study

Phylogenetic analysis of the Galapagos tortoises revealed that there is three distinct lineages within the subspecies found on Santa Cruz, which was already part of a species complex. The combination of morphological characters and genetic data indicated that one of these lineages should be described as a new taxon (presumably at subspecies level) (Russello et al. 2005). Interestingly, however, I found a paper from 2012 where each subspecies of Galapagos tortoise had been raised to species level (Poulakakis et al. 2012). While this arrangement may suit sub-editors who write bad news headlines, it is not correct, though. Consultation with the most recent annotated checklist of turtle taxonomy (van Dijk et al. 2011) revealed that the Galapagos tortoises are still being treated as a species complex – i.e., a species that comprises numerous subspecies.

Is it the end?

Yes. The world has indeed lost a subspecies – but it’s not really a big deal and we lose subspecies all the time. For this reason, incidentally, you don’t hear much about ‘species conservation’ anymore. The loss of a subspecies means even less to the public than the loss of a species, despite each subspecies contributing to biodiversity. However, with increasing sophistication and precision of molecular techniques, we may find more subspecies of Galapagos tortoises within the extant and extinct populations. Lonesome George may have had more cousins that we originally thought.

References:

Mallet (2001) Subspecies, semispecies, superspecies. In: Encyclopedia of biodiversity. SA Levin (ed). Academic Press.

Poulakakis et al. 2012. Unravelling the peculiarities of island life: Vicariance, dispersal and the diversification of the extinct and extant giant Galapagos tortoises. Molecular Ecology 21, 160-173.

Russello et al. 2005. A Cryptic taxon of Galapagos tortoise in conservation peril. Biology Letters 1, 287-290.

van Dijk et al. 2011. Turtles of the world, 2011 update: Annotated checklist of taxonomy, synonymy, distribution, and conservation status. Chelonian Research Monographs no. 5.