• Tag Archives species count
  • It’s over 9,000!

    Last year was a busy year for me. As such the site had to go into dormancy yet again. This year doesn’t look to be any less hectic, but I couldn’t bear to have the site continue to stagnate. So in an attempt to jump-start things again I am going to try and push out some smaller updates.

    Which brings us to our topic.

    The Reptile-Database recently released the current known/generally accepted species count for reptiles. It is now at a whopping 9,952 species! For comparison, when I was growing up the standard species count for reptiles hovered around 6500–6700 species. In fact one can still probably find this widely cited figure in books today. Even when I started the Reptipage some 16 years ago, the total species count was approximately 7,500 species. So in the span of those 16 years, our knowledge of extant reptile diversity has grown by 33%. That’s pretty impressive. Especially when compared to other amniotes. For instance birds are routinely cited as having 10,000 species. The most recent species count for Aves is: 10,530 (IOC World Bird List), an increase of just 5.3%. Mammals were cited as having 5000 species when I was growing up. The most recent (2008) count I could find shows that this class now contains 5,488 species (IUCN Red List); an increase of only 9.8%.

    Part of the reason for the larger spike in reptile species counts vs. mammals and birds is due to a new interest in reptiles themselves. Much of the history of Reptilia is one of revulsion, lumping, and overall wastebinning. However, now with the rise of herpetoculture and the acknowlegement that reptiles represent more than just a “stepping-stone” towards mammals and birds, herpetology has seen a bit of a renaissance in taxonomy. Another reason for this spike in species counts for reptiles can be attributed to the use of molecular techniques to ascertain differences in populations, along with better morphological data (such as those used to help determine that Crocodylus suchus was a real species and not just a variant of the C. niloticus) as well as better ecological data. This spike in species count has come about largely through the elevation of subspecies rather than the discovery of new species (though that is still happening). Herpetology has had a long history of lumping taxa that seem similar enough. This reluctance to split populations into distinct species rather than populations variations had artificially limited the actual species counts. Along with the elevation of subspecies to full species, there has also been a trend to elevate many subgenera to full genus status. This move is somewhat more controversial as the question always pops up of what the ever moving criteria for a genus are. Of course the criteria for species are hardly set in stone either. Ultimately taxonomy is a largely arbitrary affair of biological bookkeeping. Despite this, the need to have these criteria is paramount. The human brain doesn’t work well without categories, even if they are largely self-imposed ones. The appeal of splitting up Reptilia like this is that it reflects a changing attitude about reptiles in general. Though it has been long known that reptiles outnumber mammals, there always seems to be an undercurrent of “but they’re all just the same lizard.” A view that reptiles may be speciose, but are still limited in their body shapes compared to mammals and birds, still pervades today. Hence one reason why there are 29 orders of mammals, some 23 orders of birds, but only 4 orders of reptiles. A move to upgrade subspecies to species and subgenera to genera adds greatly to dispelling the myth that reptiles are the forgettable “intermediate forms” on the tree of life.

    Example of the different “genericometers” of taxonomists. Top left–right: Different members of the Anolis genus: A. proboscis and A. sagrei. Bottom left–right: Different genera of wild cats: Leopardus pardalis and Leptailurus serval. Anolis photos from: Lucas Bustamante and lanare (wikipedia). Serval photo from Giuseppe Mazza. Ocelot photos is unattributed but widely found on the internet

    Regardless of these higher order relationships it looks like Reptilia will officially comprise over 10,000 species by the end of the year [Note: See the comments].

    That is pretty awesome.