Were azhdarchid pterosaurs really terrestrial stalkers? The evidence says yes, yes they (probably) were | Tetrapod Zoology, Scientific American

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Regular Tet Zoo readers will be familiar with azhdarchid pterosaurs and the debate that’s surrounded their ecology and behaviour. Within recent decades, these remarkable, often gigantic, long-necked, long-billed but proportionally short-winged toothless Cretaceous pterosaurs have been imagined as ‘mega-skimmers’, as heron-like waders, as obligate scavengers of dinosaur carcasses, and even as sandpiper-like littoral foragers.

Back in 2008, Mark Witton and I argued that azhdarchids possess a suite of anatomical features that make it most likely that they were terrestrial stalkers: that is, that – while they were adept, specialised soarers, great at rapidly covering extraordinary distances – they seemingly foraged on foot in both wooded and open terrestrial environments, walking quadrupedally with an efficient, narrow gait, reaching down with their long necks and bills to grab small animals, bits of carrion and perhaps fruits and other edible bits of plants (Witton & Naish 2008). Azhdarchids don’t have any precise modern analogues, but we suggested that their behaviour and lifestyle most closely resembled that of modern ground horbills and terrestrial-foraging populations of marabou stork. [Adjacent ground hornbill photo - I really, really love the composition of this image - by Rod Waddington.]

This view of terrestrial stalking azhdarchids receives support from the anatomy and proportions of these animals, from the environments and animal communities in which their remains are preserved, and from trackway evidence (there’s a long, continuous trackway preserved in Upper Cretaceous Korean sediments, seemingly made by a quadrupedally walking azhdarchid*) (Witton & Naish 2008).

* A trackway argued to have been produced by a bipedal giant azhdarchid was recently published. There are some issues with the conclusions of this study. Stay tuned.

If you need a refresher on any of this, check out the articles linked to below – there’s quite a bit on azhdarchids in the Tet Zoo archives, plus the Witton & Naish (2008) paper is open-access and available to all.

Written By: By Darren Naish
continue to source article at blogs.scientificamerican.com

5 COMMENTS

  1. Astonishing beast. Very long, tubular neck vertebrae suggests to me that neck elongation was favoured so that the head/beak killing/eating machinery can sweep out a large horizontal patch while the body & limbs can remain absolutely still in “quadruped” mode. Could be useful in peering down from a great height into long vegetation to locate & zoom in on hidden, ground-dwelling prey & their nests. A prehistoric drone attack if you’re a small, fluffy dino.

  2. Cretaceous pterosaurs have been imagined as ‘mega-skimmers’, as heron-like waders, as obligate scavengers of dinosaur carcasses, and even as sandpiper-like littoral foragers.

    If we look at modern wading birds, we see flight as a means of escape from predators and as transport to new feeding grounds. Once they arrive at mudflats, they become terrestrial foragers.

    Similarly, some bats on islands in isolated habitats, have become more terrestrial in their foraging, in the absence of competition for those ecological niches.

    Unlike most bats which catch their prey in the air, the short-tailed bat has adapted to hunting on the ground. It is regarded as the world’s most terrestrial bat, and has evolved to fill the niche of mice or shrews in other parts of the world. The terrestrial behaviour of the species makes it particularly vulnerable to predation by rats and feral cats, which were introduced to New Zealand by Europeans.

  3. There was a BBC program on a few years back called Planet Dinosaur, and its last episode featured an azhdarchid genus known as Hatzegopteryx. The program depicted them as island-hopping apex predators, landing on all fours and walking about, snatching up smaller dinosaurs and swallowing them whole.

    They did strongly resemble herons as they hunted. I remember noting that herons swallow their prey whole right after snatching it up, and in a moment of morbid curiosity, I wondered what it would be like for the prey in its last moments. Not a pleasant way to go.

    Even eerier, these creatures were the size of giraffes, but probably weighed as much as a man, and their beaked heads were huge. It’s probably just as well they went extinct, given how they managed to be both terrestrial and aerial hunters.

  4. Its amazing to think that recent humans of a few thousand years ago had to deal with giant vultures and condors capable of taking children and were often depicted as such on ancient monuments in south America and the middle east..

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