Tuesday, June 28, 2016

Mark Witton Delves Into Giant Azhdarchid Pterosaur Arambourgiania

When people talk about giant azhdarchid pterosaurs (odds are most readers of this blog don't need an introduction to azhdarchids, but if you do, click here) they typically mention two taxa. The first is Quetzalcoatlus northropi, a giant Texan pterosaur discovered in the 1970s and now one of the most famous pterosaurs of all (Lawson 1975, Langston 1981). The second is Hatzegopteryx thambema, a relatively robust giant discovered in the 1990s and initially - because of its size and reinforced bone construction - thought to be a giant predatory dinosaur (see Buffetaut et al. 2003). From internet forums to TV show producers, if you want to chat about giant pterosaurs, these species are your most likely subjects.

Many readers will be aware that these aren't the only giant azhdarchids, however. The record of these animals cannot be described as extensive, but it is sufficient to indicate that they were present across most of the world and probably not particularly rare in Late Cretaceous ecosystems. But most fossils of giant azhdarchids are unnameable on account of being too fragmentary, being represented by parts of undiagnostic anatomy, or being too poorly preserved. This makes it all the more surprising that the third named giant azhdarchid doesn't get much attention: the Maastrichtian species Arambourgiania philadelphiae, known from several bones from phosphate mines in Jordan.

I'm not sure why we generally overlook this giant. Perhaps it's because Arambourgiania - 'Arambourg's giant' - is one of those old-fashioned names which works better in translation than the original Greek. It certainly doesn't sound as evocative or exotic as Quetzalcoatlus or Hatzegopteryx. Moreover, it's the least known of the three named giants, being primarily represented by a long - 620 mm - cylindrical neck vertebra, and not much else. The other named giants are not well represented either, but we have more than a handful of bones for them, and they're represented by intuitively intriguing anatomies: giant wing skeletons, bits of skull and jaw and so on. But whatever the cause, there are reasons to consider our relative neglect of Arambourgiania as unwarranted. It may not be as well-known as Quetzalcoatlus, or as immediately intriguing as Hatzegopteryx, but if you're interested in giant azhdarchids (and, hey, who isn't?) you this animal deserves your attention just as much as the other species. Here are just three reasons why.

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