In keeping with Richard’s aquatic theme for the previous TotW, this week the ichthyosaur Hauffiopteryx typicus has the honour of being the last TotW of January 2014. It also has the honour of being the first post to announce some exciting work (unpublished at time of writing) being carried out by Ryan on the first 3D reconstruction of an ichthyosaur (amongst other firsts, see below!).
During the Mesozoic, marine environments were very different. In modern oceans, marine reptiles (turtles, sea snakes, marine iguanas, saltwater crocs etc.) aren’t hugely important in the grand scheme of things, with only around 100 species around today (compared to the 30,000 ish species of teleost fish swimming about). However, take it back to the Mesozoic (especially from the Jurassic onwards, for everything except ichthyosaurs) and marine reptiles dominated the higher trophic levels, with 5 big groups (ichthyosaurs, plesiosaurs, pliosaurs, mosasaurs and thalattosuchians) emerging by the Cretaceous. We see a huge range in morphological diversity, from long necked plesiosaurs (e.g. Elasmosaurus, and the amazingly named Attenborosaurus), pliosaurs with heads reaching over 2.5m in length, crocodiles trying to be sharks, and finally ichthyosaurs.
Whilst ichthyosaurs seem a little less awesome than ‘shark crocs‘, Predator X and the Loch Ness Monster, ichthyosaurs have a wealth of published literature that makes them really cool. Looking at the organisms’ gross anatomy, it looks fish-like, and true, it is the first tetrapod to adapt a fish-like body plan, allowing them to adopt (over the course of the Triassic and the early Jurassic) a more thunniform body plan, aiding more efficient swimiming. This has led ichthyosaurs to conquer both shallow sea and open ocean environments. Ichthyosaurs also have incredible eyesight (see Motani 1999), allowing them to be efficient deep-water predators. Speaking of feeding, they also may adopt suction feeding (although heavily debated). Shastasaurus is also the largest marine reptile ever described (take that Predator X). They’ve also been shown to give birth to live young, as modern whales and some sharks do. As well the aforementioned cool stuff, ichthyosaurs have made a splash (heh) in Nature recently, with an ichthyosaur (along with a mosasaur) providing the first direct evidence of skin pigmentation in the fossil record which aren’t feathers. This has lead to the conclusion that ichthyosaurs may have been dark coloured all over (rather than countershading, seen in some modern cetaceans, for example).
However, poor little Hauffiopteryx, as yet, has received little attention. Up until 2008 the genus Hauffiopteryx was previously described as just another species of Stenopterygius (S. hauffianus, von Huene 1931). In 2008, Maisch et al. redescribed S. haffianus specimens, leading to the establishment of a new genus, Hauffiopteryx , with H. typicus being the only species within it. H. typicus has significantly larger orbits and a much more slender rostrum (snout) than S. hauffianus (amongst other apomorphies).
More Hauffiopteryx trivia:
- Up to 3m long
- From the Toarcian (early Jurassic, 182.7-181.8 Ma) of England, Luxembourg and Germany.
- Small size thought to possibly indicate ventures into shallower waters to feed.
Yet, in 2011 Caine & Benton described 8 rediscovered specimens (initially from Somerset, England), all infants and juveniles. These 8 individuals (both H. typicus and S. triscissus) are all remarkably preserved (with some soft tissue preservation). One specimen in particular, M1399, may well turn out to be incredibly important.
As you can see from the pictures of M1399, it is exceptionally preserved in 3D, which is uncommon in the usually laterally compressed ichthyosaur fossil material. This is extremely exciting, because it means we can CT scan it and explore the cranial anatomy of ichthyosaurs in three dimensions. Which by the way, has never really been done before (aside for some work on ichthyosaur teeth, see references), and is even more amazing considering M1399 is a wee juvenile. And that’s exactly what I’ve been up to lately. For the past few months I’ve been beavering away in the tomography lab, attempting to create M1399’s (which I’ve come to affectionately call ‘The Hauff’) 3D cranial reconstruction. So far results have been really interesting, we’ve seen some things which (according to my research so far) has never been seen in ichthyosaurs before. Due to the great 3D preservation, we’re hoping to reconstruct one of the first ichthyosaur endocast (and maybe alongside some more functional/musculature stuff). Unfortunately that’s all I can say right now, as it’s still a long way off from being published (hopefully later this year/2015). As soon as I can tell you guys more, I’ll post right here on TDS.
Motani, R. et al. (1999). Large eyes in deep diving ichthyosaurs. Nature 402, 747.
Lindgren, J. et al. (2014). Skin pigmentation provides of convergent melanism in extinct marine reptiles. Nature doi:10.1038/nature12899.
Motani, R. (2005). Evolution of fish-shaped reptiles (Reptilia: Ichthyopterygia) in their physical environments and constraints. Annu. Rev. Earth Planet. Sci. 33, 395–420.
Motani, R. (2009). The Evolution of Marine Reptiles. Evo Edu Outreach 2, 224-235.
Fröbisch, N., B. et al. (2013). Macropredatory ichthyosaur from the Middle Triassic and the origin of modern trophic networks. PNAS, 110(4), 1393-1397.
Sanders, P., M. et al. (2011). Short-Snouted Toothless Ichthyosaur from China Suggests Late Triassic Diversification of Suction Feeding Ichthyosaurs. PLoS ONE 6(5): e19480.
Motani R. et al. (2013) Absence of Suction Feeding Ichthyosaurs and Its Implications for Triassic Mesopelagic Paleoecology. PLoS ONE 8(12): e66075. doi:10.1371/journal.pone.0066075
Caine, H. & Benton M., J. (2011). Ichthyosauria from the Upper Lias of Strawberry Bank, England. Palaeontology 54 (5), 1069-1093.
Motani, R. (2005) Detailed tooth morphology in a durophagous ichthyosaur captured by 3D laser scanner,
Journal of Vertebrate Paleontology, 25:2, 462-465, DOI: 10.1671/0272-4634(2005)025[0462:DTMIAD]2.0.CO;2