Sunday, January 29, 2012

Southern California Research Trip, Part 4: Page Museum at the La Brea tar pits

After our last day of research at NHMLAC, Sarah, Morgan, and I drove to LAX to drop Morgan off for his flight back to the rockies. Sarah and I continued on, and had a two day trip planned ahead: first, we would visit the Page Museum of La Brea Discoveries in Hollywood, and then we'd drive north on Highway 1 from Santa Monica north through Malibu, Oxnard, Santa Barbara, Santa Maria, San Luis Obispo, Big Sur, and eventually through Monterey on our way back to the San Francisco area. We took a ton of great photos at the Page Museum which we arrived at just before opening; I've included some of the better and more informative photos here.

The front of the uniquely designed Page Museum. The museum is shaped like a square with a botanical garden courtyard, and above the museum, a large bas-relief is supported by that scaffolding.

A poor Columbian Mammoth is in deep... stuff.

My wife snapped this photo of tar bubbling up outside the museum. It's amazing how much tar is still seeping up. On my last visit in 2004, I didn't see anything around the park that was half this good; you can clearly see here the leaf litter and detritus that covers and camouflages the tar, while also seeing some obviously viscous, black, cartoon style tar bubbling up.

The famous Pit 91 excavation, which is temporarily on hold during the project 23 excavation a stone's throw away.
One of the panels from the bas relief above the museum, depicting a teratorn confronting a ground sloth.
A Columbian Mammoth skeleton, which I look way too happy to see (considering it's not marine, that is).
One of these things is not like the other ones...
My wife attempting to pull the plunger, showing how damned difficult it is.
The right canine is not the thing that's important in this shot, it's the left canine; although this is not a marine carnivoran, I'm interested in tooth eruption in carnivorans in general, and this made my day.
Skull and life restoration of Merriam's giant condor, Teratornis merriami. Still not as big as Pelagornis, but impressive and terrifying none the less.
Lots and lots of dire wolves (Canis dirus). This has to be my favorite display in the entire museum... it's beautifully constructed.
The spectacularly large and robust skeleton of the American Lion, Panthera atrox.
What? I thought this was the American Lion? Some recent studies have indicated the skull and mandibular morphology of Panthera atrox is more similar to the extant Jaguar (Panthera onca) than it is to African Lions (Panthera leo). There is a conflicting molecular study done with ancient DNA, however, but I'll save that for another time. Here's a question for any readers in the know: who the hell is Naegele? Joseph Leidy named the damn thing after all, so why isn't it named Leidy's Giant Jaguar?

A new American Lion specimen named "Fluffy" was recently excavated, and there was this temporary case which had in it what I thought was one of the better exhibits in the whole place: a three dimensional representation of the skeleton, using the same skeletal elements of a housecat. As a taphonomist, I particularly enjoyed this.
The bubble prep lab at the Page.
I love seeing stuff like this in prep labs. Apparently Arctodus is a patriot.
Is that a walrus in there? Damn, it's just a Smilodon. I really loved this display showing the three dimensional configuration of bones.
Smilodon again.
A bee outside the Page Museum. This has no relevance to the rest of the post, but it is a pretty picture, no?
A composite of two panoramic shots my wife took showing the bas relief.

A great shot taken by my wife of the wall of dire wolf skulls.

Up next: Southern California Research Trip, Part 5 - detailing the Santa Barbara Museum, the coast, and the conclusion of the series of posts.

Friday, January 27, 2012

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.

Thursday, January 26, 2012

Southern California Research Trip, Part 3: Natural History Museum of Los Angeles County (collections)

The purpose for our trip to visit the LACM collections was to examine a large collection of pinniped fossils housed there. Curator Emeritus Dr. "Larry" Barnes has been studying fossil pinnipeds since his master's thesis in the late 1960's (which he published in 1972, on Allodesmus and other desmatophocid pinnipeds), and has researched a wide variety of fossil pinnipeds including the early diverging and 'primitive' enaliarctines (a paraphyletic group of early pinnipeds), the relatively large and aberrant desmatophocids (an extinct group of phocoids known only from the North Pacific), all manners of fossil walruses, and fossil sea lions and fur seals. Larry has named quite a few fossil pinniped taxa from the northeastern Pacific region (Enaliarctos mitchelli, Pteronarctos goedertae, Pteronarctos piersoni, Pacificotaria hadromma, Desmatophoca brachycephala, Allodesmus gracilis, Proneotherium repenningi, Pelagiarctos thomasi, Gomphotaria pugnax, and Proterozetes ulysses), and there are a whole slew of holotype specimens to look at at the LACM - including a number of other important finds, including crania and jaws of the walrus Imagotaria downsi and the even earlier Neotherium mirum (but not quite as old as Proneotherium...). Our goal was to photograph all of these skulls and jaws, and take all sorts of measurements of them for our research. Between Morgan and I, we took about 5 gigabytes of photographs of these fossils. At the moment, we have two concurrent research projects which will soon be culminating in submittable manuscripts: a phylogenetic analysis of fossil and modern sea lions and fur seals (Otariidae; Morgan gave a talk on this at SVP this last fall), and another project describing some new material of the extinct "killer" walrus Pelagiarctos, originally described by Larry Barnes from the Sharktooth Hill Bonebed, and discovered by LACM head preparator and all around fun guy Howell Thomas. At bare minimum, we needed to examine, photograph, and measure the holotype "chin" and the referred teeth. Anything else we got done was a bonus - and our bonus included looking at dozens and dozens of skulls, jaws, and teeth of various other pinnipeds.

The hollywood hills can be seen very well from the prep lab, which is several floors up. You can just make out the hollywood sign below the top of the mountains.

The holotype "chin" of Pelagiarctos thomasi.

A referred lower left third or fourth premolar of Pelagiarctos, published by Barnes (1988).

My wife borrowed some of the clay we used for propping oddly shaped specimens up during photography and made a walrus and a manatee; the manatee even has
motorboat propeller scars (just for J. Velez-Juarbe!)

A referred lower jaw of Neotherium mirum from the Sharktooth Hill Bonebed, published by Barnes (1988); this is the only other early walrus from the middle Miocene bonebed.

My wife happened to find a book of 3D cat photos with 3D glasses. Don't ask.

Three different jaws of Allodesmus from the Round Mountain silt; but how many species? According to Barnes, there are three species: the topmost is the holotype of Allodesmus kelloggi, the middle is the holotype of Allodesmus kernensis, and the bottom one is Allodesmus gracilis. Others would lump all these in to Allodesmus kernensis (which would have taxonomic priority).

Three different early walruses! From left to right, they are Proneotherium repenningi from the Astoria Formation of Oregon (early Middle Miocene), Neotherium mirum from the Sharktooth Hill Bonebed of California (late Middle Miocene), and Imagotaria downsi from the Santa Margarita Sandstone (early Late Miocene) of Santa Cruz County, California.

The beautifully preserved holotype skull of Pacificotaria hadromma from the Astoria Formation of Oregon. According to Berta (1994), this may be a junior synonym of Pteronarctos.

Morgan and I conducting research amid a chaotic mess of fossil pinnipeds and other paleontological debris.

Downtown Los Angeles from the window in the prep lab. The US Bank tower can be seen in the middle. If you recall, it was blown to smithereens in Independence Day.

The rostrum and upper dentition of a referred snout of Desmatophoca oregonensis.

Morgan photographing the obscenely gigantic jaw of the bizarre double tusked behemoth of a walrus Gomphotaria pugnax. Seriously, that thing is offensively large.

The holotype skull of Allodesmus kelloggi, described by Ed Mitchell in the mid 1960's from the Sharktooth Hill Bonebed.

An undescribed late Pleistocene jaw of a California sea lion, Zalophus sp., from the Newport Bay mesa.

Last, but not least, another shot of those three walruses -
Proneotherium, Neotherium, and Imagotaria.

What's up next? One or two more posts on the southern CA trip including the Page Museum as well as the Santa Barbara Museum of Natural History, and eventually, I should probably try and cover some recent marine mammal research, I still have to cover a paper I got published on our wedding day, Kolponomos, and a bazillion other things.

Monday, January 23, 2012

Southern California Research Trip, Part 2: Natural History Museum of Los Angeles County (exhibits)

After two and a half days at the San Diego MNH, Morgan, Sarah, and I said our goodbyes to our friends and colleagues there (Joe El Adli, Eric Ekdale, and Tom Demere), and piled into my tiny honda for the drive up to LA - we decided that spending another morning at SDNHM would allow us to drive up to LACM and miss all the morning traffic. We arrived at the museum at about 2 in the afternoon, and after chatting with Curator Emeritus Dr. Lawrence ('Larry') Barnes for a little bit, we got right to work examining fossil pinnipeds. I'll discuss the collections visit in the next post - first I'd like to talk a bit about the new mammal paleontology hall.

The new "Age of Mammals" hall has been in the works for several years, and has taken quite a bit of time on behalf of most of the Paleontology Dept. employees at LACM. I've seen a few photos on the internet prior to my visit, so I knew a little of what to expect. I don't have much of a research interest concerning terrestrial mammals - so, sorry terrestrial paleomammalogists who happen to be reading this blog (admittedly a very, very, very small fraction of humanity), but I'm going to ignore the land mammals. Some of the marine mammal highlights include a mounted skeleton of the sperm whale Aulophyseter morricei from the Sharktooth Hill Bonebed, as well as the holotype skeleton of the phocoid pinniped Allodesmus kelloggi (which, according to some, may be a junior synonym of Allodesmus kernensis), and adult and juvenile mounted skeletons of the late Miocene dugongid Dusisiren jordani, which were collected from the Santa Margarita Sandstone in Santa Cruz County. Lastly, and arguably the centerpiece of the marine mammal exhibits - is a beautiful new skeleton of Paleoparadoxia (which apparently may be named as a new genus in the near or distant future). Aside from these, there are a handful of skulls and pinniped fossils on display, including the world's oldest delphinid dolphin fossil - a complete skull from the Monterey Formation, unnamed and still undescribed. Overall, however - I must admit I was a bit underwhelmed. Certainly on the lower floor, there are plenty of fossil land mammals just packed in. But the top floor, which was an odd mix of La Brea specimens and marine mammals, there was just a lot of empty space, and there wasn't really that much marine mammal material on display, which is surprising given that the LACM holds one of the largest fossil marine mammal collections in North America.

Not in the Age of Mammals hall, but I had to include a picture of my favorite
pinniped, Callorhinus ursinus.

The juvenile skeleton of Aulophyseter morricei from the Sharktooth Hill Bonebed. This individual is under 50% adult size. The only known skeleton of this taxon.

This also was not taken in the Age of Mammals hall - but it goes to show that my wife likes to photobomb fossils all the time. I mostly put this up here to demonstrate to others that she is an awful person.

The holotype skeleton of Allodesmus kelloggi.

A cast of the holotype (and only known specimen) skull and jaw of the desmatophocid pinniped Atopotarus courseni. Atopotarus has occasionally been recombined as Allodesmus courseni, but desmatophocid taxonomy will have to be covered in a separate post.

A referred lower jaw of the Miocene sirenian Dioplotherium allisoni.

The adult female and juvenile skeletons of Dusisiren jordani from the Santa Margarita Sandstone in Santa Cruz County. The juvenile is so damn cute...

A Paleoparadoxia ulna with sharktooth bite marks. This specimen belongs to the mounted skeleton shown below.

A rather bizarrely portrayed fossil dolphin in some artwork related to sharktooth bite marks; I'm sure the artist was more interested and familiar with depicting sharks than cetaceans.

One of the exhibits I was looking forward to as a taphonomist - the gut contents of a Basilosaurus cetoides skeleton from Mississippi! It had as gut contents when it died
a mass of fish bones.

The articulated forelimb of the late Miocene delphinoid Albireo whistleri, originally described by Larry Barnes from the Almejas Formation at Cedros Island in Baja California.

The business end of the new Paleoparadoxia skeleton.

I'll leave you with this large size image of the Paleoparadoxia skeleton - my dslr camera doesn't have a wide angle lens, so I had to stitch these photos together for an ultra-size photo (I have a much larger version; contact me if you want it). And yes, that is the intrepid Morgan Churchill standing behind its ass.