New artwork: reconstruction of a remingtonocetid whale

Some time last fall I sat down and sketched out a drawing of Remingtonocetus, after Bajpai et al. (2011) was published. This new study described a new, nearly complete (and beautifully preserved) skull of Remingtonocetus harudiensis from India. The remingtonocetids are possible one of the only monophyletic groups of archaeocetes, and all appear to be relatively small-bodied, with ridiculously big heads and long rostra, very tiny and dorsally placed orbits, heterodont dentitions, and long tails. Perhaps the best way to imagine a remingtonocetid is to picture an otter with the (furry) head of a gharial.

The skull of Remingtonocetus harudiensis, from Bajpai et al. 2011.

The holotype skeleton of Kutchicetus minimus, from Bajpai and Thewissen (2000).

I had inadvertently sketched the head too small on the body, so when I completed the drawing over Christmas break with my wife's family in Montana, I ended up with a critter with a head that is way too small (although it looks like a less absurd beast, to be quite honest).

The original, unaltered drawing.

To fix this, I did some editing in photoshop after I had scanned the image - mostly by enlarging it's head about 20% or so. I also decided to experiment with texturing, and ended up with something that fairly convincingly looks like fur; I'm still experimenting with drawing fur in pencil, and as you can see between these two - the photoshopped version looks quite a bit better. Texturing can be pretty difficult on a small drawing - the original is only about 6" long from nose to tail. I was also able to make the wet fur on 'his' nose a little 'spikier'.

The modified version of the artwork. Overall, I'm quite satisfied with this piece, and am rather surprised that I was able to portray an archaeocete cetacean as "cute" - archaeocetes in general are pretty nasty, scary looking beasts, like Ambulocetus, Basilosaurus, Georgiacetus, and Dorudon.

The skull of Andrewsiphius, from Thewissen and Bajpai (2009).

There are a number of different remingtonocetids, including Remingtonocetus, Andrewsiphius, Kutchicetus, Attockicetus, and Dalanistes. Only Andrewsiphius and Remingtonocetus are known from good, well preserved crania. Bajpai et al. (2011) suggested that, based on the strange skull anatomy of Remingtonocetus, that remingtonocetids were ambush predators that were heavily reliant upon hearing rather than sight. The muscle attachment area is very large, and coupled with the very narrow jaws - suggests that remingtonocetids had a weak, but very fast bite, well suited for ambushing and catching small fish. Additionally, because Remingtonocetus was aquatic, the extremely long snout was probably not an adaptation for improved olfaction; Bajpai et al. (2011) hypothesize that as Remingtonocetus was one of the first marine cetaceans, this may have been an adaptation towards retention of freshwater during respiration.

Next up - continuation of the southern California research trip, Kolponomos, my Purisima vertebrate assemblage paper, desmatophocid taxonomy, etc.

Further reading:

A different kind of Whale, at Laelaps

Bajpai, S., and J.G.M. Thewissen. 2000. A new, dimunitive Eocene whale from Kachchh (Gujarat, India) and its implications for locomotor evolution of cetaceans. Current Science, 79(10):1478-1482.

Thewissen, J., & Bajpai, S. (2009). New Skeletal Material of Andrewsiphius and Kutchicetus, Two Eocene Cetaceans from India. Journal of Paleontology, 83 (5), 635-663.

Bajpai, S., Thewissen, J.G.M., and R.W. Conley. 2011. Cranial anatomy of Middle Eocene Remingtonocetus (Cetacea, Mammalia) from Kutch, India. Journal of Paleontology 85(4):703-718.

New artwork IV: Tyrannosaurus rex maxilla

For quite a while I've wanted to draw a theropod maxilla. They're pretty neat looking elements, and tyrannosaurid maxillae at that are pretty rugose, and have some interesting textures. I did this drawing once I got back from New York earlier in the month. I'm very happy with this piece, and it isn't very big - maybe 8" wide.
Here's a quiz: what's important about this specimen? The specimen # is UCMP 118742.

New artwork III: Smilodon life restoration

Late last year I was asked by my buddy/coauthor Morgan Churchill to draw a life restoration of Smilodon or some other machairodontid for a new exhibit at the University of Wyoming Geology Museum.
Unfortunately, I didn't really get a chance to start it until January, and I finished it a few weeks ago. This was largely an experiment for me, as I've never really drawn fur before; I've had plenty of experience drawing hair in portraits of people, but never really furry mammals. I've never really drawn any life restorations of (non-human) mammals before, for that matter. I suspect that doing something hairless like marine mammals might be quite a bit easier. Anyway, I clearly need more practice. Perhaps next time, I'll try and copy a photograph, to at least get some experience with texturing fur, instead of attempting to "paste" it onto a fossil face I've never seen before.

Any way, I'm relatively happy with the outcome. I initially wanted to draw it with it's mouth closed, but I figured that would look less impressive for the museum exhibit. So, yawning is a behavior that inadvertently shows off an animal's oral weaponry that is far more common than snarling, baring of teeth, etc. - and very few paleoartists have attempted Smilodon yawning. Almost all Smilodon art I've seen depicts the animal snarling, which of course looks very impressive, but it does get a little boring.

New artwork II: 'rediscovered' specimen drawing

About two months ago, I was cleaning off my desk and found a sheet of vellum paper with an old specimen drawing I had done. This drawing was is of a pair of associated dentaries of the Pliocene fur seal Callorhinus gilmorei. I first presented on this fantastic specimen on my 2007 SVP poster at the Austin, TX meeting.


Unfortunately, I discovered this about three months after my manuscript describing this fossil was accepted in JVP, and there was no way to include it in the published article. To be honest, I could probably do better now, but I think it turned out reasonably well for a journal article figure. In the future I'm going to do a lot more technical illustrations of individual specimens, partly as practice, but also to showcase myself.

Stay tuned! The article will be published in the March 2011 issue of JVP: that's sometime in the next couple of weeks. (Holy god, it's March in only 48 hours!). More artwork is on its way.

Boessenecker, R.W. In Press. New records of the fur seal Callorhinus (Carnivora: Otariidae) from the Plio-Pleistocene Rio Dell Formation of Northern California and comments on otariid dental evolution. Journal of Vertebrate Paleontology 31:2. 14pp.

New artwork I: Cynthiacetus reconstruction

Hey folks,

Some of you cetophiles may have already seen photos of this specimen floating around on the internet. I thought the mount was pretty dynamic, and would work well as a skeletal reconstruction - so I did it. A photo of this specimen which has thus far only been identified as cf. Cynthiacetus is featured in a recent paper by Christian de Muizon.


Cynthiacetus is a dorudontine archaeocete that was originally described from the Eocene of Mississippi by Mark Uhen. He also referred a few vertebrae and a partial skeleton to this taxon from the Eocene of Egypt. This new skeleton (and I am not sure how complete it is) is from the Eocene of Peru, and is part of a large new collection of Peruvian archaeocete cetaceans we will be hearing about over the next few years.

New artwork for Fall 2010

Hey Folks,

I'll have some more on taphonomy in the next few days, but before I get to that, I've got some new artwork to post instead. As I've previously alluded to, this has been an absolute heinous semester, even though I've only taken 1 credit in courses. I've spent the entire semester working on several manuscript projects (at least one of which is about to come to fruition; more on that in the coming weeks). Just over this weekend alone, I've received page proofs for my first paper, received final acceptance for another paper, and submitted the revisions for a third paper. Life is good.From left to right: Agujaceratops, Pentaceratops, Anchiceratops, Arrhinoceratops, and adult Triceratops (="Torosaurus").

In addition to all these, I've been busy with several art projects. The longest project (and still incomplete) is a series of cranial drawings of chasmosaurine dinosaurs for Denver Fowler, for his research he presented earlier this month at SVP for his Romer prize presentation.

Agujaceratops mariscalensis for Denver Fowler's Romer presentation.Subadult Triceratops for John Scannella's Romer presentation.

John Scannella, another Ph.D. student here at MSU/MOR, has recently earned some time in the limelight for killing "Torosaurus" (now known to be just the adult form of Triceratops) - although many people over the summer misinterpreted his study as somehow killing Triceratops instead. John asked me back in September to redraw one of Hatcher's beautiful plates of Triceratops for his Romer presentation. Unfortunately, the skull that Hatcher figured lacked a nasal horn, and he needed it to have one... so I drew it with one, and I can only hope that my drawing doesn't make Hatcher roll over in his grave.

Here's the paleontological 800-lb gorilla in the room: formerly Torosaurus, but what has convincingly shown by Scannella and Horner (2010) to simply the adult form of Triceratops, although many unfortunately still cling to the olde wayes of palaeontological research. This was actually for Denver Fowler's talk rather than John's, and is based on a rather complete "Torosaurus" skull here at Museum of the Rockies.
This I just did for fun over the summer - I actually did this up at Lake Tahoe (and only took about 3 hours, even though it's about two feet wide) while I was on vacation there over the summer. This I believe is some kind of Diplodocus. Some dinosaurs are pretty, although in many cases I could care less which one it actually is. Drawing sauropod dinosaurs is OK, because they're almost as big and almost as cool as a baleen whale. Sorry dinosaur fans, they just never quite made it, but they get an A for effort.Lastly, this is one of my most recent drawings - this is part of a big bird bone. But that's all I'll say for now; I only put this up here because its a good example of a specimen drawing I've done. This one only took about 4 hours.

Anyway, time for shameless self promotion: I auctioned a bunch of prints off at the SVP benefit auction earlier this month, and made a total of ~350$ for the auction, which, according to Denver F., is something like 1.7% of the entire proceeds from the auction. That feels pretty damn good on multiple levels- for one, just knowing that I helped raise that much money (and it only cost me about six bucks to print all that stuff out, including the plastic sleeves) and two, that it was because people liked my artwork and were willing to bid anywhere from 30-80 bucks for prints. Unframed, unmatted prints in a plastic bag.

Anyway, due to the overwhelmingly positive reaction I got for my artwork at the auction, I recently started an account on ETSY.com so that I can try and sell some prints of this stuff, and be able to afford food, and gas, and things that are usually denied to graduate students. I'm just kidding about that, but being able to make a few bucks off doing what I love would be pretty fulfilling. Anyway, if you're interested, go ahead and take a look at my Etsy account.

Reconstructing a fossil walrus, part 2: the finished product

So, quick rehash of part 1, in case you're really that lazy. To reconstruct the cranium and jaws of Dusignathus santacruzensis (which has an 'exploded' holotype cranium with isolated parts that don't quite match up well), I used more complete material of a younger species, Dusignathus seftoni, from the late Pliocene San Diego Formation. I used the skull of D. seftoni as a template to 'hang' the various parts of D. santacruzensis on to.

Cranial mosaic of Dusignathus seftoni with holotypic fragments of Dusignathus santacruzensis 'hung on'.

From here, it was pretty much an exercise in printing it off, tracing it, and inking it out (followed of course by scanning and some image editing). Below is the finished product.

New cranial restoration of Dusignathus santacruzensis.

Cranial restoration of Mitchell (1975).

Compare this with the older cranial restoration of Dusignathus santacruzensis by Mitchell (1975); there are some obvious differences, including a significantly smaller orbit, and a dorsoventrally shallower cranium, which serves to make the dentary appear much more massive.

Cranial reconstruction of Dusignathus santacruzensis with photos of crania
of Dusignathus seftoni and Gomphotaria pugnax. Not to scale.

So... that's basically that. During my lifetime, I want to test this hypothesis of what this animal looked like by finding a new cranium of D. santacruzensis; this won't be easy, and will probably take a lot more searching (i.e. decades). Wishful thinking, I know... Otherwise, I hope that this gives you folks some ideas on how to tackle similar problems with incomplete material you may be studying.

Mitchell, E.D., jr. 1975. Parallelism and convergence in the evolution of the otariidae and phocidae. In Biology of the Seal, p. 12-26.

Reconstructing a fossil walrus, part 1: the enigmatic Dusignathus santacruzensis

For a recent manuscript project I found myself in need of a cranial reconstruction of the strange pinniped Dusignathus santacruzensis. D. santacruzensis was named from the Purisima Formation in 1927 by Remington Kellogg, the father of modern marine mammal paleontology. Research and interviews conducted by F.A Perry have successfully relocated the type locality, which evaded Kellogg and later forays by E.D. Mitchell in the early 1960's. The holotype specimen consists of a few cranium fragments including a partial maxilla bearing a procumbent canine, a squamosal, and a fragment of the 'vertex' of the skull (a term usually relegated to cetaceans, but utilized for odobenids by Demere [1994]), as well as both dentaries. The 'exploded' nature of the cranium is actually fairly literal; interviews by F.A. Perry indicate the collector 'poked it with a stick and the skull exploded', and only some of the cranium fragments were recovered. The dentaries are thus far the most distinctive element of the taxon; they are very robust, also with a procumbent canine, curious postcanine teeth with anterior and posterior wear facets, and a sinuous ventral border of the dentary (the first and last are synapomorphies of the Dusignathinae - Demere [1994]). Mitchell (1975) depicted the first reconstruction of the cranium of D. santacruzensis.

Mitchell's 1975 reconstruction of Dusignathus santacruzensis.

Unfortunately, no more cranial remains of Dusignathus santacruzensis have been recovered from the Purisima Formation since. Trust me, this isn't for lack of trying - dozens of dedicated amateurs and professionals (myself included, for the last few years) have been scouring the coastal exposures of the Purisima Formation nonstop since the 1970's. Plenty of odobenid postcrania have been collected, in addition to an edentulous odobenine walrus cranium (Barnes and Perry, 1989).

Former display at the Santa Cruz Museum of Natural History of casts of the Dusignathus santacruzensis holotype (without squamosal) based on Mitchell's reconstruction. Done by my colleague, Frank Perry. I apologize for the reversed image.

A gigantic pinniped skeleton was unearthed in the late 1980's from the Capistrano Formation, and was named Gomphotaria pugnax (Barnes and Raschke, 1991). This very strange animal was initially perceived as being very different from Dusignathus in terms of its mandibular morphology. Gomphotaria, which had a 40cm+ skull, bore two stout, worn, procumbent tusks - in the cranium and in the mandible.

Gomphotaria pugnax, a pinniped straight from hell.

Collections from the late Pliocene San Diego Formation of southern California included two new species of walruses - the extremely bizarre toothless Valenictus chulavistensis (which deserves several posts by itself), and the 'bizarrer' Dusignathus seftoni, both described by Tom Demere (1994a), the curator of SDNHM. D. seftoni is known from several crania and jaws, a partial skeleton, and a handful of postcranial elements. This animal had a cranium generally similar to the well known Imagotaria, and very similar to the 'killer walrus' Pontolis, and Gomphotaria. A trait shared with Gomphotaria were the possession of upper and lower (but less procumbent) tusks, also highly worn. The dentary shared similarities with both taxa; the sinuous ventral border, but it had a gigantic lower canine.

Referred crania of Dusignathus seftoni, described by Demere (1994).

Although the holotype of D. santacruzensis does not have very large canines, Demere (1994b) suggested that the specimen represents a female. Indeed, the canines are relatively small for any male pinniped, although the skull fragments do preserve a sagittal crest. The root of the lower canine is also exceptionally long, suggesting some potential.

The holotype right dentary of Dusignathus santacruzensis, from
Repenning and Tedford (1977).

Sure enough, in March 2008 I collected (from near the type locality) a pair of associated tusks (one upper, one lower) - one is straight, and the other curved posteriorly and laterally; these are adult teeth (based on root pulp cavity closure), and lack the highly abraded and parasagittally oriented tusks of Gomphotaria, and instead have tusks more similar to D. seftoni (albeit unworn). Additionally, these tusks are substantially smaller than in Gomphotaria, which was a monster in comparison (although dwarfed by Pontolis magnus, another dusignathine, one of the largest carnivorans of all time, possibly only smaller than elephant seals). These are best identified as male tusks of D. santacruzensis. These tusks are larger than any male D. seftoni specimen, and indicate an animal that is pretty damn sexually dimorphic. One of the tusks exhibits curvature in a parasaggital plane, but also lateral curvature. Tom Demere has successfully convinced me that the curved tusk is the lower canine, very similar to D. seftoni.

Unfortunately, dentaries of female D. seftoni are not yet known, and male dentaries of D. santacruzensis are not yet known. I guess I just have to keep looking in the Purisima Formation!

Coming up - the actual reconstruction process I used, now that the essential (albeit convoluted) backstory is done.

T. A. Demere. 1994a. Two new species of fossil walruses (Pinnipedia: Odobenidae) from the Upper Pliocene San Diego Formation, California. Proceedings of the San Diego Society of Natural History 29:77-98

Demere, T.A. 1994b. The family Odobenidae : a phylogenetic analysis of fossil and living taxa. Proceedings of the San Diego Society of Natural History 10:99-123.

R. Kellogg. 1927. Fossil Pinnipeds from California. Contributions to Palaeontology from the Carnegie Institution of Washington 27-37

Mitchell, E.D., jr. 1975. Parallelism and convergence in the evolution of the otariidae and phocidae. In Biology of the Seal, p. 12-26.

Repenning, C. and Tedford, T., 1977. Otarioid seals of the Neogene. USGS Professional Paper 992.

New skeletal drawing: Acrophoca longirostris

Hey all,

Here's a new drawing I was able to complete on one of my days off between Geology Field Camp projects. It's a skeletal drawing of Acrophoca longirostris, a very strange pinniped from the early Pliocene Pisco Formation of Peru (as well as from Chile; Walsh and Naish 2002). Acrophoca is a Monachine true seal (family Phocidae), and as stated above, is known from the early Pliocene of the Southeast Pacific. According to the phylogeny of Demere et al. 2003, Acrophoca is the sister taxon of the fearsome Leopard seal, Hydrurga leptonyx. Acrophoca was originally named by Muizon (1981). The skeleton I drew this from can be seen on display at the USNM. Ordinarily I'd give more information, but I need to pack up for my road trip.



Demere, T.A., A. Berta and P.J. Adam. 2003. Pinnipedimorph evolutionary biogeography. Bulletin of the American Museum of Natural History 13:32-76.

C. Muizon. 1981. Les vertebres fossiles de la Formation Pisco (Perou). Premiere parti: Deux nouveaux Monachina (Phocidae, Mammalia) du Pliocene de Sud-Sacaco. Recherche sur les grandes civilisations Memoire 6:1-150

Walsh, S. A. & Naish, D. 2002. Fossil seals from late Neogene deposits in South America: a new pinniped (Carnivora, Mammalia) assemblage from Chile. Palaeontology 45: 821-842.

Another skeletal reconstruction

Here's another skeletal reconstruction I've done. This time, it's of the large Middle-Late Miocene pinniped Allodesmus.
Allodesmus is a genus of very large sea lion-like pinniped. This is based on a skeletal mount of Allodesmus kernensis from the Middle Miocene Sharktooth Hill Bonebed of Central California. Allodesmus is known from the early Middle Miocene of California (Allodesmus packardi, found near Stanford University) and even the early Late Miocene of California (Santa Cruz County). Several species of Allodesmus have also been recovered from Baja California, the late Miocene of Washington state, and Japan. Thus, it appeared that Allodesmus had a circum-North Pacific distribution for a substantial chunk of the Miocene.

Allodesmus kernensis was approximately 10' long, and about in the size range of extant Steller's Sea Lions (Eumetopias jubatus). It is placed in the extinct family Desmatophocidae, which it shares with the much smaller Desmatophoca, two species of which are known from the early and middle Miocene of Oregon and Washington.

Correction...

So, I totally forgot a very important part of the walrus anatomy, which my girlfriend reminded me...

But I'm not going to tell you. Its time for you to play 'which of these is not like the others...'

What's different?

AND, more importantly, does anyone out there (I.E. any of Annalisa's ex-students) have any suggestions on how to improve the reconstruction?

If noone does, then I'll assume my artwork is 100% perfect (as it usually is).

Reconstruction of a fossil walrus

At left is another reconstruction, this time of a fossil walrus, Valenictus chulavistensis. Valenictus chulavistensis was described by Tom Demere, the Paleontology Curator of the San Diego Natural History Museum.

Valenictus is a very odd pinniped, for several reasons. For one, V. chulavistensis (the only well known species of Valenictus) lacks all of its teeth, save the two elongate canines, which are fairly similar to the tusks of the extant walrus, Odobenus rosmarus. Nevertheless, modern walruses do not use their dentition for feeding, so while the disappearance of the noncanine dentition is unprecendented in other pinnipeds, it is not completely unsurprising as modern walrus noncanine teeth are nearly vestigial, so to speak.

Valenictus also has a number of postcranial features that are highly derived; the fore- and hind-limb bones do not closely resemble those of other fossil or modern Odobenidae (walruses). Also, the skeleton of Valenictus is pachyostotic and osteosclerotic (pachyostotic = thick bones, osteosclerotic = dense bones, more or less). This is possibly a ballast-like adaptation for maintaining bouyancy in a warm water environment.

These adaptations are also seen in sirenians. This is probably an adaptation for feeding in shallow, warm waters: the extant walrus feeds on benthic molluscs in shallow (but very, very cold) water, and (most) sirenians feed on seagrass in the photic zone. Valenictus chulavistensis evidently had many of the same feeding adaptations for molluscivory as does Odobenus, and Valenictus thus far has been found in relatively warm-watter settings, based on mollusc and microfossil assemblages. Additionally, other fossils of Valenictus are known from the proto-gulf of California (i.e. the Salton trough), which was hypersaline - this would have made a large, fat animal even more positively bouyant in the water column, a major hindrance to a critter that relies on benthic invertebrates as a food source.

I'll do some more in-depth posts on this fascinating fossil walrus in the future.

Reconstruction of a fossil mysticete

At left is a skeletal reconstruction I recently did, which was supposed to go in my talk for SVP this year on a bizarre baleen whale named Herpetocetus bramblei. This skeletal reconstruction is based on a referred skeleton of Herpetocetus sendaicus from the early Pliocene of Japan.

Herpetocetus is a very weird type of baleen whale, and I will most likely be posting about some of its oddities in the future.

For example, there is a very odd 'style' of the suturing between the rostral elements (e.g. maxillae, premaxillae, nasals) and the posterior cranium (particularly the frontals). The mandible of this taxon is extremely strange, as is the jaw joint itself (e.g. glenoid fossa), and the auditory/temporal region of the cranium. The postcranial skeleton is, however, fairly normal for a cetacean.

Lastly, most species of Herpetocetus would have been in the ballpark of 4-5 meters in length, while H. bramblei, the largest known species, would have been in the 5-6 meter range. Still, in American, thats about 15-18 feet, for a large Herpetocetus. Most modern mysticetes occur in the 10 meter-plus range (again, 30 feet or more in American). There are a couple of smallish freaks, such as the Dwarf Minke Whale (an unnamed subspecies of Balaenoptera acutorostrata) and the Pygmy Right Whale (Caperea marginata), in the 6-8 meter and 4-6 meter range, respectively.

Another odd feature about fossil mysticetes is the tendency towards small size with respect to extant mysticetes. For one, this could be climatically controlled (large mysticetes are pretty much relegated to cold, nutrient rich waters much of the year). This also, however, could be sampling bias; several authors have suggested that because the majority of fossil mysticete crania are small (e.g. Herpetocetus), then fossil mysticetes probably were all that small (strongly paraphrased). However, the problem with this statement is that the skull of a 90 foot blue whale is over 12 feet long and 6+ feet wide; thats not exactly easy to excavate as a fossil, and not exactly easy to find complete, either.

Size in fossil cetaceans is worth a post all by itself; that'll come later.