Controversial ceratopsids revisited: woolly Pachyrhinosaurus and scavenging Styracosaurus

Spurned on by a print request, I've spent free time this week revising two images of ceratopsids which may be familiar to long-term readers: my woolly Pachyrhinosaurus perotorum and scavenging Styracosaurus albertensis. The former is now just over two years old, and the latter a whopping eight years old - wow, have I really been messing about with internet palaeoart for that long?

Maastrichtian Alaska was quite chilly, but woolly Pachyrhinosaurus perotorum doesn't care. See this post for the original image and exploration of the concept shown here. Prints are available.

Because I appreciate some folks are fond of my original paintings, I haven't deviated too far from the original compositions and instead just added more detail, tweaked colour values and tidied up some sketchy areas. I'm very conscious of not 'pulling a Lucas' on my old work. Most importantly, the science has been improved/corrected: the cranial morphology of Pachyrhinosaurus perotorum is now correct to that species (like a doofus, I based the morphology in the original image on a different Pachyrhinosaurus species) and the tyrannosaur in the scavenging scene is appropriately filamentous. Thanks to Darren Naish, Zachary Miller and Christian Kammerer for discussions of Styracosaurus horn shape.

Have these depictions have been supported or refuted by any new discoveries? As far as I'm aware, skin impressions still remain elusive for Pachyrhinosaurus, although new data has emerged on the facial integument of juveniles (Fiorillo and Tykoski 2013). The 2014 discovery of Kulinadromeus and its assortment of filament-like scales, true filaments and other integumentary oddities (Godefroit et al. 2014) might indirectly add credence to the idea of shaggy ceratopsids, however. Along with Psittacosaurus and Tianyulong, Kulindadromeus shows that the evolution of ornithischian integument was complex, that single animals can bear a suite of different integument types, and that the assumption of dinosaur skin being ancestrally scaly is uncertain. The weird scales in (unpublished) skin impressions of Triceratops are further evidence that 'one skin fits all' approaches to reconstructing these animals are likely flawed, and that even clades with relatively limited anatomical disparity - like ceratopsids - had diverse integuments. Thus, the idea that some members of Dinosauria may have looked very different to our traditional interpretations is being strengthened by genuine data, and shaggy arctic ceratopsids remain a fun extrapolation of that concept. For further discussion on these points, check out my discussion of version one of the woollysaur painting.

The Campanian centrosaurine Styracosaurus albertensis scavenges the remains of a tyrannosaurid. He was going for warpaint on his face, but he ended up at 'Tonto'. For fun, the original 2007 version can be seen here. Prints are available.

What of scavenging ceratopsids, as in the reworked 2007 image of a tyrannosaurid-eating Styracosaurus? Ceratopsid omnivory has yet to be explored in the technical literature and, to my knowledge, remains best represented by a short paragraph in Paul (1991). More recently, Mallon and Anderson (2013) provided reasoning for why ceratopsids were not predatory animals, although their discussion seems to consider 'carnivory' synonymous with 'predation': opportunistic scavenging or omnivory are not explored. This leaves most discussion of ceratopsid scavenging online, and several famous denizens of the online palaeontological community seem to support it. Back in 2007 I wrote a long essay substantiating the idea. That essay is no longer online*, but the argument is pretty straightforward:

*After eight years, I figured it's time to archive my old Flickr stream. The bulk of the content there is not representative of modern science or a good representation of my work, so it's been taken offline. I won't pretend I'm not a bit sad to do so, but there's obviously reason for bringing internet searches to my best, most recent work, not images I created when first learning how to paint.

1. As is well-known, a number of modern herbivores eat animal remains on occasion. This may reflect nutrient stress (thought to explain carrion use by hippos, which is not as common as 'common knowledge' might suggest) or else a method of supplementing a mineral-deficient diet (as in deer, cows, giraffes and a host of other hoofed mammals - Hutson et al. 2013). Remarkably, some cases of hippo carnivory involve the hippos killing animals first, and they will also scare other carnivores from kills to obtain carcass access (Dudley 1998). Of further interest is that entire herds of hippos will chew on carcasses when available - these are not the acts of rogue, aggressive or aberrant individuals (Dudley 1998). Note that studies on the carnivorous tendancies of generally herbivorous animals are in their infancy, and it may be that this behaviour is more common and opportunistic than we currently realise.
2. Other species, such as pigs, ingest animal matter as part of their normal diets. Studies on some pigs suggest 28% of their diet is derived from animals, either being invertebrates or carrion (e.g. Thomson, and Challies 1988). There is no reason to think that large extinct animals were incapable of comparable omnivory, but we restrict most discussion of it to smaller dinosaurs and pterosaurs. We can predict that such animals should have jaws mostly adapted for herbivory (e.g. teeth suited to browsing and grazing, long 'cheek' toothrows, vertically displaced jaw joints etc.) but would also have some means to process animal remains (e.g. crushing teeth to break bones, caniform teeth or sharp beaks for ripping meat etc.).
3. Ceratopsid jaws certainly belonged to primarily herbivorous species capable of chewing their food, but their approach to herbivory was unusual. Their teeth and jaws, unlike other herbivorous dinosaurs and mammals, were incapable of grinding plant matter. Instead, they sliced food into pieces, their teeth sliding vertically past one other like scissors. Ceratopsid beaks are also unusually deep and narrow compared to other dinosaurian herbivores, and recall the beaks of parrots in many respects. The beaks of these birds are famously powerful, enabling their owners to access a range of nuts, seeds and animal matter (e.g. Greene 1999). The diet of of ceratopsids has been questioned by palaeontologists because chopping plant matter is not common among modern herbivores. To the contrary, most food slicers are carnivores - meat is easier to chop and slice into easily digested chunks than it is to grind into a paste. One sensible suggestion is that ceratopsids ingested particularly fibrous, woody plant matter (see Mallon and Anderson 2013 and references therein). We might imagine them devastating Cretaceous shrubs, removing entire chunks of tree - leaves, branches and bark - with each bite, or overturning plants with their huge heads to access their roots and tubers. However, it is odd that their jaws aren't more convergent with those of other herbivores, as grinding mechanisms have developed so many times in multiple tetrapod lineage and might be considered optimal for breaking down plant matter. So, maybe ceratopsid jaws were used for more than simply eating plants, and their shearing teeth and hooked beaks are the traits of omnivory we mentioned above, equally capable of slicing plants and animal remains. Opening carcasses, snapping smaller bones and slicing meat was almost certainly possible with their jaws and beaks, and we might imagine ceratopids as Mesozoic variants of pigs: largely herbivorous species with opportunistic carnivorous tendencies, and certainly capable of competing with strict carnivores for carcass access. The possibility that they could occasionally kill other animals for food, as demonstrated by the aforementioned hippos, is not unreasonable.

Back in 2007 I mentioned a possible smoking gun for this idea - a rumoured Psittacosaurus specimen with bony gut content. Since then, it's become apparent that that specimen either doesn't exist, has disappeared or has otherwise been forgotten about - it's best to consider that an unsubstantiated rumour for now. Despite this, I still think the concept of ceratopsian omnivory has legs: maybe a technical paper on the topic would be worthwhile.

Bumblebee Conservation Trust charity prints: an update

In my last post I mentioned you can buy a print of my Tyrannosaurus vs. bees painting and donate money to the Bumblebee Conservation Trust. I'm happy to say £55 has been raised in the last week for this cause, and thanks to those who've bought in. It would be great to make even more money however: if you'd like to contribute, find out more here.

Of course, prints are available for all my other work too, including the ceratopsid pieces above. Contact me at wittonprints@gmail.com to order one, and check out this page for prices and other details.

References

• Dudley, J. P. (1998). Reports of carnivory by the common hippo Hippopotamus amphibius: short communication. South African Journal of Wildlife Research, 28(2), 58-59.
• Fiorillo, A. R., & Tykoski, R. S. (2013). An immature Pachyrhinosaurus perotorum (Dinosauria: Ceratopsidae) nasal reveals unexpected complexity of craniofacial ontogeny and integument in Pachyrhinosaurus. PloS one, 8(6), e65802.
• Godefroit, P., Sinitsa, S. M., Dhouailly, D., Bolotsky, Y. L., Sizov, A. V., McNamara, M. E. & Spagna, P. (2014). A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science, 345(6195), 451-455.
• Greene, T. C. (1995). Aspects of the ecology of Antipodes Island Parakeet (Cyanoramphus unicolor) and Reischek's Parakeet (C. novaezelandiae hochstetten) on Antipodes Island, October-November 1995. Notornis 46: 301-31
• Hutson, J. M., Burke, C. C., & Haynes, G. (2013). Osteophagia and bone modifications by giraffe and other large ungulates. Journal of Archaeological Science, 40(12), 4139-4149.
• Mallon, J. C., & Anderson, J. S. (2014). The functional and palaeoecological implications of tooth morphology and wear for the megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta, Canada. PloS one, 9(6), e98605.
• Paul, G.S. (1991). The many myths, some old, some new, of dinosaurology. Modern Geology, 16: 69-99
• Thomson, C., & Challies, C. N. (1988). Diet of feral pigs in the podocarp-tawa forests of the Urewera Ranges. New Zealand journal of ecology, 11, 73-78.

Tyrannosaurus, Mesozoic bees, and bee-friendly palaeoart!

The stem-birds and the bees - two juvenile Tyrannosaurus rex investigate a Cretaceous honey bee nest. Prints are available, and you'll be contributing to bee conservation if you buy one in February 2015. See below for details.

Here's something you don't see every day - a depiction of a beehive in the Mesozoic. Bees rarely make it into Mesozoic palaeoart, but genuine bees were certainly contemporaneous with non-avian dinosaurs. The oldest bees have been found in Early Cretaceous amber inclusions (Poinar and Danforth 2006) and their fossils show that many traits of modern bees - including those related to collecting pollen - were already present by this time. Indeed, one of the oldest known bees is preserved with bits of pollen stuck to its hair. Trace fossils also suggest that many modern bee behaviours - nest building, burrowing etc. - were also taking place in the Mesozoic (e.g. Genise et al. 2002).

Calibrating the Mesozoic diversification of bees is difficult because their fossils are exceedingly rare. However, the likelihood that early bees were pollinating early flowering plants means that their diversification is of interest to not only palaeoentomologists but also those trying to understand the establishment of modern ecosystems. The Mesozoic can seem like a time of weird and wonderful plants and animals, but this view is skewed by our interest in unusual Mesozoic megafauna. A lot of our modern biota and ecologies have their origins around these animals, so much so that time-travelling humans would probably find many Mesozoic settings quite familiar. It seems that Mesozoic bee diversity fits this idea, as studies of bee DNA suggests crown-group bees evolved in the Early Cretaceous and quickly diversified into groups we would recognise from the modern day (Cardinal and Danforth 2011, 2013). This radiation likely included the adoption of at least ancestral variants of complex social behaviour we associate with modern bees (Cardinal and Danforth 2011).

One of my favourite implications of this work is the suggestion that the Apini were present in the Late Cretaceous (Cardinal and Danforth 2011, 2013). Apini are better known as honey bees, and, assuming their ability to make and store honey in nests was ancestral to the entire group, we may have seen Late Cretaceous reptiles raiding their colonies like modern animal rob their nests today. I find concepts like this really 'ground' the behaviour of fossil animals - the idea that a theropod or small ornithopod might partake in sting-filled nest vandalism to obtain energy-filled honeycomb seems like a very real, likely concept, and far more grounded than the gladiator matches we often see associated with dinosaur foraging. I've tried to capture some of that reality in the image above, showing dog-sized juvenile Tyrannosaurus rex taking on a colony of increasingly angry honey bees. Getting past the bee defenses is not proving easy, and the smaller Tyrannosaurus is close to adopting a full-on duck-and-cover defensive response to his aggressors. Videos of bears failing nest raids often show them hunkering down and covering their faces with their paws - I thought it would be fun to have Tyrannosaurus try that with it's proportionally small arms.

Bee-friendly palaeoart. Yes, it's a thing now.

My sudden interest in Mesozoic bees was catalysed by a donation request for an auction at Cumberland House, Portsmouth's Natural History Museum. The auction is raising money for a new beehive at the museum and, rather than just printing off some old work, I thought it would be fun to produce something new and relevant to the event. I'll be providing a framed version of the above work as a lot for sale - check out the Cumberland House Natural History Museum Friends Facebook page for the latest on the auction.

The Cumberland House auction is not the only way to get a piece of palaeoart while helping bee-related causes - for the next month, any copy of this print I sell will directly help a leading UK bee charity. Yes, bees need charities now, being in trouble globally thanks to habitat loss, climate change and the wide use of insecticides (see, for instance, this, this, and this for a taster of this issue). Several national populations and species have gone extinct in recent years, and more are set to follow. This is not just a problem for the 'natural' world: we rely on bees to pollinate many of our crops. Food prices and availability are set to change for the worse as bee populations and diversity dwindle so, whether you consider conservation an issue or not, we need to do something about their decline. For this reason, all February 2015 sale proceeds of my Tyrannosaurus and bees print will be donated to the Bumblebee Conservation Trust, a UK charity devoted to restoring bee habitats, encouraging bee-friendly policies at local, national and European governmental level, and raising awareness of the bee conservation crisis. Prices for my prints start at £20 (+£5 shipping) - most of that will go straight to the bees, and you get a print out of the deal. Contact me at wittonprints@gmail.com if your want to know more.

References

• Cardinal, S., & Danforth, B. N. (2011). The antiquity and evolutionary history of social behavior in bees. PLoS One, 6(6), e21086.
• Cardinal, S., & Danforth, B. N. (2013). Bees diversified in the age of eudicots. Proceedings of the Royal Society of London B: Biological Sciences, 280(1755), 20122686.
• Genise, J. F., Sciutto, J. C., Laza, J. H., González, M. G., & Bellosi, E. S. (2002). Fossil bee nests, coleopteran pupal chambers and tuffaceous paleosols from the Late Cretaceous Laguna Palacios Formation, Central Patagonia (Argentina). Palaeogeography, Palaeoclimatology, Palaeoecology, 177(3), 215-235.
• Poinar, G. O., & Danforth, B. N. (2006). A fossil bee from Early Cretaceous Burmese amber. Science, 314(5799), 614-614.