A new Pelagiarctos specimen, part 1

Late last year on the fossil forum (www.thefossilforum.com) where I help identify fossils for amateur collectors, I saw a photo of a pinniped tooth collected by my good friend and Tate Museum preparator JP Cavigelli from the Sharktooth Hill bonebed. It looked like it had a few too many cusps to represent any pinniped other than Pelagiarctos thomasi, so I asked JP to take a few measurements - and sure enough, the tooth is huge, and double the size of the smaller walrus Neotherium mirum. The additional cusps and presence of a cuspate lingual cingulum (cingulum is a ridge of enamel just above the base of the crown, and lingual means the tongue side of the tooth) are unique among walruses to Pelagiarctos and Imagotaria. Imagotaria is far younger (late Miocene, rather than middle Miocene). JP was kind enough to donate the specimen to the Tate museum where he worked, and Morgan Churchill and I actually referred the specimen to Pelagiarctos thomasi in our PLoS article on Pelagiarctos.

The new specimen of Pelagiarctos thomasi (TATE 2694) collected by J.P. Cavigelli in 2012.

Preparator Sophie sculpts a pedestal onto the broken root of the tooth.

Morgan is down here in New Zealand and Australia for a two month EAPSI (East Asia and Pacific Summer Institute) fellowship, with the intent to utilize a statistical analysis to test the phylogenetic position of the problematic Pleistocene sea lion Neophoca palatina from New Zealand. About two months ago my labmate Carolina Loch-Silva suggested Morgan bring a Pelagiarctos tooth with him in order to secure an enamel fragment to examine its enamel structure - possibly as a way to take another stab at the feeding ecology of Pelagiarctos. To recap, Larry Barnes (1988) originally hypothesized Pelagiarctos to be a macrophagous 'killer' walrus, although our reevaluation of the data (Boessenecker and Churchill 2013) suggests that it was a dietary generalist like most modern pinnipeds, including robust sea lions.

The tooth on its pedestal.

Even though Carolina's sampling method will not remove much of a tooth fragment, I was still interested in molding and casting the specimen. There are less than a dozen teeth of Pelagiarctos in museum collections (many more exist in private hands, which us researchers have to ignore for all intents and purposes), it would be useful to provide casts of the specimen to various west coast museums such as UCMP, LACM, the San Diego NHM, and the Cooper Center; casts of the specimen will also be sent back to the Tate Museum, the Smithsonian, and the National Museum of Nature and Science in Tokyo.

Mixing silicone and silicone catalyst requires careful measuring on a scale.

 The tooth on its pedestal and base, with a single coat of silicone painted on to capture fine detail. Unfortunately, this coat never cured - we're using somewhat expired silicone, and it can be finicky when it cures, often requiring extra catalyst. We ended up pulling the rubber off and redoing it as a single pour.

For an easy small fossil like a tooth, comparably fewer steps are necessary for molding and casting. Firstly, in order to keep silicone (or latex for that matter) from invading small pores and cracks and pulling out fragments of bone, a consolidant such as vinac or PVB needs to be painted on the specimen. For a small specimen like this, there are three ways to mold it: 1) with latex, paint several layers on to make a sleeve, which can be pulled off the tooth (or cast) and inverted; 2) a two part mold, or 3) a single pour 'plug' mold. For small specimens, my friend and fellow student at MSU Denver Fowler suggested cutting up older latex molds, pouring the fragments in to a film canister, embedding the small fossil within said latex clippings, and then pouring in latex to fill the voids and form a nice plug; after enough casts are made, you recycle the latex and do it again with another specimen. We decided to do a similar single pour mold. Instead of using a film canister, Sophie made a small cylinder of clay as a base, planted it on a flat sheet of clay, and then taped a cylinder of plastic sheet and planted that into the clay to act as a dam. We first tried to paint a layer of silicone onto the tooth to capture fine details, but for whatever reason it never cured properly, so Sophie stripped that layer off and we mixed up some more silicone for a single pour. We ended up having too much silicone mixed up, and asked Ewan if he had anything handy which we could mold, so he gave us a small squalodontid tooth.

The squalodontid tooth showing the acetate sheet dam. At this stage, once the silicone is mixed, it can be poured directly into the tube.

Both plug molds, with dental plaster freshly poured and waiting to cure.

Next up: pouring plaster and resin casts.

Morphometric analysis of NZ bivalves

A sample of Cyclocardia bivalves from the Otekaike Limestone, Hakataramea Valley, south island.

Although in the Otago Geology department we mainly focus on fossil marine vertebrates from the South Island, some occasional work is done on marine invertebrates. One of Ewan's undergraduate students was interested in doing a morphometric analysis of bivalves, and Ewan suggested she work on the small cockle-like bivalve Cyclocardia. Cyclocardia is not abundant within the late Oligocene Otekaike Limestone, but it is distinctive and easily identified in the field.

Some of these have naticid gastropod borings, probably from Magnatica.

On one of our last field days in Hakataramea Valley in the austral fall, we took a break from excavating a large mysticete to collect some Cyclocardia specimens for the student project. Over about a 20 minute period, the four of us (Ewan, lab tech Sophie, fellow student Yoshi Tanaka, and myself) picked up about 120 specimens or so. Some have margins that are too chipped.
 

 It must be nice to have large sample sizes...

Berardius stranding in Southland

 Back in January, two Arnoux's beaked whales stranded down near Invercargill, and Ewan was interested in obtaining flippers for fellow Ph.D. student Moyna Mueller's dissertation on the comparative forelimb anatomy and myology of odontocetes. Collectively species of Berardius are known as the giant beaked whales, and include the northern hemisphere Berardius bairdii (Baird's beaked whale), and the southern hemisphere Berardius arnuxii. Little is known about these cetaceans, and the Arnoux's beaked whale in particular is rarely seen - Ewan encouraged me to come down, as it is probably a once in a lifetime experience for a northern hemisphere cetacean researcher to witness. Ewan and others headed down the day before to start work on the first carcass, while I stayed in town to get some more dissertation work done, and headed down the next day with Alan Tennyson (paleornithologist at Te Papa/National Museum of NZ) and Travis Park (Ph.D. student, Monash University) who were in town for the Southern Connections conference. Labmate Felix Marx joined us for the second day, and we were also joined by Aussie paleontologist Maria Zammit, who did her Ph.D. with Benjamin Kear at the South Australian Museum in Adelaide.

We arrived at Omaui Beach after missing a few turns and driving all the way into Bluff - alarmingly, Ewan's team was nowhere to be found, and more problematic - there was no carcass either! After a few minutes a local DOC volunteer showed up and told us that the carcass probably floated north along the beach, although an earlier search failed to locate it.

 Our half of the team heading off down the beach towards the probable location of the carcass.

 

 On our way up the shore to the stranding, we came across a single Fiordland Crested Penguin - Eudyptes pachyrhynchus - a rare penguin to spot. Photo courtesy Travis Parker.

 

A better photo of the penguin. This guy was not feeling well - he had been bitten by a shark, taken in by some locals to DOC, and after keeping him/her over night they put it back on the beach. Photo courtesy Travis Park.

This was my first penguin sighting in the wild - pretty exciting! Especially since I had not yet seen the far more common little blue penguins (Eudyptula) or Yellow-eyed penguin (Megadyptes).

Carcass spotted! The carcass as we first smelled it. Actually, it didn't smell too badly. Photo courtesy Travis Park.

Te Papa (National Museum of New Zealand) paleornithologist Alan Tennyson examines the carcass.
Photo courtesy Travis Park.

The carcass was a bit bloated even after only about 24-48 hours of decay, and the tongue and vulva were already quite swollen and extruding from the body. It also left this bloody puddle around the rock. 

 Shark bite marks, almost certainly from a great white (Carcharodon carcharias). It's unclear whether or not this set is partially healed or not. Photo courtesy Travis Park.

A glamor shot of the carcass on the coastline.

 Yours truly posing alongside the dead ziphiid.

Travis Park after enjoying the dissection. Photo courtesy Travis Park.

The pathologist Stu, from Massey, washing off his hands.

Alan switching out tools. Photo courtesy Travis Park.

Travis sharpens his flensing knife a bit. Photo courtesy Travis Park.

On the way back to the cars we found a bone sticking out of the beach sands - turned out to be the occipital condyles of a large cetacean skull. We're still not sure what it is; my initial impression was a very large ziphiid or a small Eubalaena, but looking back at the photos I think it very well could be a Balaenoptera. We were unable to budge it, and with numb hands substituting for actual tools, not to mention the driving rain, high wind, and rapidly cooling conditions typical of a balmy summer day in Southland (think northern Scotland), we quickly decided to leave it and head back into town to get some much needed food. From left: Alan Tennyson, Travis Park (in hat), Marcus Richards (in khaki coveralls).

We were actually fairly far from the dunes, so the spot is probably only accessible during low tides. Fellow marine tetrapod paleontologist Maria Zammit watches with amusement as she keeps her hands nice and warm. The local DOC volunteer wasn't quite as excited by the prospect of bones.

Due to the water level, any sand we removed would just settle back in around the skull.

Our half of the team heading back to Omaui Beach near Bluff.

Lost photos from the Smithsonian

I recently came across some photos that Ewan had emailed me a long time ago from our Smithsonian visit last fall, from the Garber oversize facility in Maryland.

This was my first time seeing a skeleton of a southern sea lion (Otaria byronia). Unfortunately, I didn't get much time to check out the skeleton of this or any other modern pinnipeds, as my offsite visits were focused on fossil and modern mysticetes relating to my Ph.D. research.

Another first: the totally bizarre skull of the Ganges river dolphin (Platanista gangetica) from Indo-Pakistan. One of the few odontocetes with obvious heterodonty, and with strange bony crests on either side of the face (part of the maxilla) that extend dorsally and wrap around the lateral and dorsal sides of the melon; the function of this structure is still not entirely understood.

New Delphinapterus illustration

I recently attempted a new drawing and experimented with adding a bit more detail than I normally do. I find that every drawing is a learning process, and I try to challenge myself by learning new techniques and styles every time I put a pencil to paper. Until about a year ago, I had never really used anything other than a #2 pencil - which is a relatively soft lead. More recently I have started using somewhat harder pencils, including a 3H - which remains sharper for longer, and can be sharpened more finely - allowing for much more detailed work.

Skull and mandible of Delphinapterus leucas from the MNHN, borrowed from Wikipedia.

Occasionally I'll see a photograph that speaks to me and looks like it would be fun (or challenging) to illustrate. A few weeks ago I found a neat looking photo of a beluga (Delphinapterus leucas) skull and mandible from the MNHN in Paris (shown above). It's a rather old mount as can be gathered from the nails and wires securing the teeth. This one was of sufficiently high resolution to elaborate minute details of the bone texture, and was an excellent candidate for an experiment in substantially more detailed illustration than what I've previously attempted.

 

The completed illustration, measuring about ~14" wide or so.

This illustration took about 20 or so hours to complete - perhaps double the time I've invested in similar sized illustrations previously. I spent about 6 hours just on the temporal region of the skull. Altogether, I am really pleased with the end result. Come to think about it, I should probably post some illustrating tutorials at some point in the future.

 Close up of the temporal region. I went a bit crazy here.

The best marine mammal-themed graffiti you'll see all day

After being here for a few weeks, Sarah and I finally walked around the Botanical Gardens in Dunedin rather than through them, and we spotted a quasi-familiar looking patch of graffiti in the canal for the Leith, the local river in North Dunedin that flows through campus (usually with a few rugby or soccer balls floating in the eddies). After a few times walking by it, I finally took a photo, and have been neglecting to put it up here for almost a year. So there you are, Viva La Walrus!

 Interesting choice to modify Che...

With near certainty I can say this is probably the last graffiti I will see for a long while that panders to my interest in odobenids.

More original content is coming, I promise! Next up will be some photos of a Berardius stranding from February, and an excavation of a couple mysticetes back in February and March.

An original Douglas Emlong painting emerges

Last week I got an email out of the blue from reader Ole Juul in British Columbia who told me that his father had purchased an original painting by Douglas Emlong, and that this painting was among his father's collection. Ole wrote:

"My parents and I both like paintings and when my dad died a few years ago, I took the remaining few from their house. This one was among them and to my surprise I had not seen it before. We used to live in Vancouver, but this one they must have gotten in their little remote town of Bralorne where they had retired. It's a great puzzlement how that painting could have gotten there. I can see that the image is one that would have enticed my father, who himself was a painter. It took me a while to warm up to it, but when I finally realized the depth of experience it contained, decided to look up the name. You, no doubt, know the small body of information that is publicly available. Emlong was indeed a very interesting person."

I was pretty happy to receive this email - there are a couple photos of paintings by Emlong in the USNM Emlong archive, as well as a couple of other paintings. Included in the archive is a photo of this painting - although it's unclear when the photo was taken and stored within the Emlong archive. I forwarded Ole's email to Ray Troll, who sent me back a photo of a photo of this painting he had taken from the archive; he was pretty happy to see a much higher resolution photo of the specimen.

Like Ole, the more I look at the painting the more I warm up to it. The swirls and small brush strokes are evocative of Van Gogh's work, but not as painstakingly composed. I love the whimsical tree above the cliff, and the rich color of the rocks. It's no wonder that Emlong painted a scene of the coast - his life, and his passion for finding incredible fossils - revolved entirely around the shoreline.

Is this a scene from Emlong's imagination - or his memory? That spire on the right hand side should be fairly easy to identify, if its the latter. However, the headland in the distance suggests that this is some sort of a large embayment - but many of the embayments along the Oregon coast have nice beaches instead of steep, rocky shores along their "inside" shores. Of course, Emlong took some trips to Alaska, and as far south as Bakersfield to visit Sharktooth hill - so it's possible that it could come from anywhere along the Pacific coast; Ray Troll said it reminded him a bit of Destruction Bay in Alaska. Furthermore - if anyone has informed suggestions for where this scene may be intended to represent - I'd be happy to hear some educated guesses.

 

 "Palisades of the Pacific" - Douglas Emlong, date unknown. Courtesy Ole, from British Columbia

As I've discussed before, Emlong was a bit of a gifted - but tortured soul. He was, most significantly, an abnormally talented amateur paleontologist, responsible for the single largest collection of marine mammal fossils amassed by a single person - including numerous "missing links" which have illuminated evolutionary transformations and the relationships of pinnipeds (Enaliarctos), desmostylians (Behemotops), early odontocetes (Simocetus), and baleen whales (Aetiocetus). Some later posts should really focus on some of the specific instances of his fossil genius. Emlong, however, had other pursuits in addition to paleontology. As shown above, he was an artist (something I can relate to) - and like his paleontology work, I assume that he received little formal training, and achieved what he did with nothing more than personal motivation (and of course, paint). Furthermore, Emlong had spent years working on a novel, which apparently was pretty psychedelic - but not enough to attract a publisher, even in the 1970's; he spent all sorts of money trying to get his book published, and even sent a copy of the manuscript to Clayton Ray at the USNM. Emlong was also a musician, and played at local concerts in Oregon. As D. R. Wallace wrote in his book Neptune's Ark, Emlong had an IQ of 138, but failed to complete college or hold down a full time job. Clayton Ray remarked that Emlong was impatient and often did not listen or consider advice given to him - another factor why I think he didn't receive formal training. The picture painted in my mind of Emlong is a bit of an inspired but headstrong genius - a dreamer whose passion and inspiration too rapid and ephemeral to always listen to criticism or instruction. I am far from anything remotely near what you could call a genius - but thanks to where and how I do fieldwork, I do feel a certain connection with Emlong; I understand that 'itch' to pack my tools and head out to the beach in search of the 'holy grail', and translate an image from my imagination onto paper. I can never hope to become even half the field paleontologist that Emlong was (with the exception of making plaster jackets and taking field notes, of course! Emlong didn't care much for either), but his unusual ability to find incredible fossils serves as a touchstone example of what we can aspire towards in west coast paleontology.

Thanks again to Ole Juul for alerting me to the existence/current whereabouts of the piece, sending me a good photo of it, and letting me post it here!