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!

Odontocete trifecta in the latest issue of Journal of Vertebrate Paleontology

I apologize for the lack of posts over the past month - the last few weeks I have been working furiously in order to complete a long list of manuscript revisions for a long manuscript for the journal Geodiversitas. Additionally, I've been trying to complete a laundry list of collaborations, which are slowly being completed. Now that I have breathing room again, welcome to the 200th post on Coastal Paleo (down under)!

Last week I was pleased to see the publication of not one, not two, but three different papers on cetaceans in the most recent JVP issue. I was also amused by the lamentation by some of my former fellow students from MSU that there weren’t enough dinosaur papers in JVP (one only!). It’s a welcome change, from my perspective – to be honest, roughly half of JVP issues have no marine mammal articles, and the majority have multiple (boooring…) dinosaur papers. To be fair, there are a hell of a lot more dinosaur researchers than there are marine mammal paleontologists, so it’s to be expected. On the other hand, despite the disappointment that comes with scrolling through brand new but marine mammal-less issues of journals, it does come with the upside that we often don’t have to add citations for numerous articles coming out while your manuscript is in review (unless it’s a long article that takes a while for review and revisions; I had a revised article I recently resubmitted which had taken about eight months from submission to completion of revisions, and I had to add citations for about a dozen new articles).

 

Comparison of Brachydelphis mazeasi (above) and Brachydelphis jahuayensis (below). 

From Lambert and Muizon (2013).

The new studies are published by my colleagues Giovanni Bianucci and Olivier Lambert, and several of their European and South American colleagues. The first paper is by Olivier and prominent French paleocetologist Christian de Muizon on a new species of Brachydelphis from the Pisco Formation of Peru. The genus was named by Muizon (1988) who described Brachydelphis mazeasi, a short-beaked pontoporiid dolphin from the Cerro La Bruja vertebrate level of the Pisco Formation in Peru, a late middle Miocene locality. Pontoporiids today are represented only by the franciscana, aka La Plata River Dolphin, Pontoporia blainvillei. It’s my wife’s favorite cetacean, which she just refers to as “francis”. They don’t really look much like dolphins the public is familiar with – it’s got odd triangular fins and an elongate beak. It’s also tiny, topping out at 1.8 meters in length (5’ for American readers). It’s not quite as freaky looking as the Ganges/Indus river dolphin (Platanista; more on this one further down), or the Amazon river dolphin (Inia), and is actually pretty cute as far as cetaceans go (so is the Yangtze river dolphin, Lipotes). Note for the Californian readers: one of the most common fossil dolphins in California, Parapontoporia, was originally considered to be a franciscana relative, but is most closely likely related to the recently extinct Lipotes. One thing all modern river dolphins share in common, aside from generally plesiomorphic skull morphology, is an elongate and narrow rostrum. Platanista and Inia also retain what are arguably the least homodont dentition of any odontocete; modern river dolphins are sort of a relic of the Miocene fauna. Note: for the rest of the article, when you see the term “river dolphins” in quotes, I’m referring to all modern and fossil platanistids, pontoporiids, iniids, and lipotids; these taxa do not form a natural monophyletic grouping, and appear to have independently evolved (a topic for another post, I think).

The holotype (top) and paratype (bottom) of Brachydelphis jahuayensis from the 

Pisco Formation of Peru. From Lambert and Muizon (2013).

Up until the description of Brachydelphis, all fossil “river dolphins” also shared an elongate rostrum (or, if not complete, the indication of an elongate rostrum) – Pontistes, Pliopontos, Ischyorhynchus, Parapontoporia, Zarhachis, Pomatodelphis, the list goes on and on. Brachydelphis on the other hand bore a tiny little rostrum, to the point where it must have resembled something like a true porpoise with weird flippers. A subsequent study reinterpreted the fragmentary Protophocoena minima from the Miocene of Belgium as a brachydelphinine (Lambert and Post 2005). The new study by Lambert and Muizon (2013) focuses on the description of a new species of Brachydelphis with a less stunted rostrum, and in a way is a bit more normal-looking. The rostrum of Brachydelphis jahuayensis, however, is still quite short relative to other “river dolphins”, and perhaps in that aspect still evocative of the name Brachydelphis. They reported on numerous new skulls which are preserved beautifully. The most fascinating aspect of the paper is the age of Brachydelphis jahuayensis – it’s from the El Jahuay vertebrate level of the Pisco Formation, which is younger than Cerro La Bruja, and thus younger than the shorter-snouted Brachydelphis mazeasi. Assuming an ancestor-descendant relationship (which I consider to be reasonable) between the two, it implies that Brachydelphis first evolved a short rostrum, and was then reversed during the late Miocene. It may not be surprising, as we already know that the cetacean rostrum is a fairly plastic feature that is readily adjusted to changes to feeding ecology (presumably, anyway). I actually was one of the reviewers for this paper, and I’m pleased to see it published. Interestingly, this younger, longer-snouted taxon was preliminarily recognized by Gutstein et al. (2009) from similarly aged strata from the Bahia Inglesa locality in Chile, which Lambert and Muizon (2013) referred to Brachydelphis jahuayensis.

 

Yet another skull of Brachydelphis jahuayensis. From Lambert and Muizon (2013).

The second paper is by the Italian paleocetologist Giovanni Bianucci on a new genus and species of oceanic dolphin from the Pliocene of Italy, Septidelphis morii. At first look, it is similar in overall proportions to many extant long beaked delphinines such as Stenella longirostris, and other Italian Pliocene delphinids such Etruridelphis giulii and Astadelphis gastaldii. It does differ from all other delphinids in having a fairly wide mesorostral groove, among other subtle features. Bianucci (2013) included it within a limited phylogenetic analysis which he used a molecular tree as a “backbone” constraint – in other words, forcing the extant species on the tree to conform to the molecular tree, and using the morphological characters to position the fossil taxa relative to the extant species. The analysis resulted in the recovery of Astadelphis, Etruridelphis, and Septidelphis as the earliest diverging delphinines, with the exception of extant Sousa chinensis. This information, in concert with molecular divergence dates, led Bianucci (2013) to suggest that perhaps extant genera of delphinids may be nearly lacking entirely in the Pliocene, and that aside from a few cases of extinct species in extant genera (e.g. Orcinus citoniensis), most modern lineages probably did not originate until the Pleistocene. One piece of evidence for this is that the majority of nodes in the molecular phylogeny of extant delphinids occur in the Pleistocene (again, based on molecular divergence dating). To summarize, this suggests perhaps an even more rapid divergence among delphinids than has been previously hypothesized.

 

The holotype cranium of Septidelphis. From Bianucci (2013).

The last (and shortest) paper is on a single earbone, also by Giovanni Bianucci, Olivier Lambert, and colleagues. This paper reports a fossil earbone of a platanistine river dolphin – closely related to the modern Ganges River dolphin – from the Amazon river basin in eastern Peru. A Ganges River dolphin relative in South America. How cool is that? It’s also only the second reported platanistine fossil ever – the first is an admittedly less convincing chunk of mandible from the early Miocene Nye Mudstone of Oregon. This new earbone is fairly strange looking (a requirement for a platanistine, to be honest), with a long and strangely curved anterior process. It shares several feature with modern Platanista. This specimen is middle Miocene in age, and indicates that platanistines used to inhabit South America. One of the more interesting aspects of this earbone is where it was preserved, environment wise: it’s found with a number of terrestrial mammals, and occurs in fluvial-lacustrine deposits with occasional marine influence. Fossils of freshwater cetaceans are notoriously rare, and include some eurhinodelphinids material from Australia (Fordyce, 1983; possibly platanistoid, according to research presented by Erich Fitzgerald at the 2010 SVP meeting), Ischyorhynchus from South America (Cozzuol, 2010) and some Pomatodelphis material from Florida. Bianucci et al. (2013) proposed the following sequence of events in the biogeographic history of Platanista: platanistines evolved in the Pacific as primarily marine odontocetes, with some becoming adapted to freshwater environments of the Amazon basin during the middle Miocene, and finally dispersing and adapting to freshwater environments of southern Asia (Platanista), with all other platanistines (as yet unknown) becoming extinct. Interestingly, where the platanistine fossil occurs is now inhabited by the Amazon river dolphin, Inia geofrrensis. Bianucci et al. (2013) also noted that an odontocete historically regarded as an iniid, Ischyorhynchus, was recovered as the sister taxon to Platanista in the Geisler et al. (2012) cladistic analysis. Further analysis is required to be sure, as many taxa jump around depending upon the type of analysis and changes in coding, but it is a tantalizing possibility that two platanistines may have been in Miocene rivers of South America.

The fossil platanistine periotic (left), compared to a modern Platanista gangetica periotic (right). From Bianucci et al. (2013).

References cited

Bianucci, G. 2013. Septidelphis morii, n. gen. et. sp., from the Pliocene of Italy: new evidence of the explosive radiation of true dolphins (Odontoceti, Delphinidae). Journal of Vertebrate Paleontology 33: 722-740.

Bianucci, G., Lambert, O., Salas-Gismondi, R., Tejada, J., Pujos, F., Urbina, M., and Antoine P.O. 2013. A Miocene relative of the Ganges River dolphin (Odontoceti, Platanistidae) from the Amazonian Basin. Journal of Vertebrate Paleontology 33:741-745.

Cozzuol, M. A. 2010. Fossil record and the evolutionary history of Inioidea; pp. 193–217 in M. Ruiz-García and J. Shostell (eds.), Biology, Evolution and Conservation of River Dolphins within South America and Asia. Nova Science Publishers, New York.

Fordyce, R.E. 1983. Rhabdosteid dolphins (Mammalia: Cetacea) from the middle Miocene, Lake Frome, South Australia. Alcheringa 7: 27-40.

Geisler, J. H., S. J. Godfrey, and O. Lambert. 2012. A new genus and species of late Miocene Inioid (Cetacea, Odontoceti) from the Meherrin River, North Carolina, U.S.A. Journal of Vertebrate Paleontology 32:198–211.

Gutstein, C. S., M. A. Cozzuol, A. O. Vargas,M. E. Su´ arez, C. L. Schultz, and D. Rubilar-Rogers. 2009. Patterns of skull variation of Brachydelphis (Cetacea, Odontoceti) from the Neogene of the southeastern Pacific. Journal of Mammalogy 90:504–519.

Lambert, O., and Muizon, C. de. 2013. A new long-snouted species of the Miocene pontoporiid dolphin Brachydephis and a review of the Mio-Pliocene marine mammal levels in the Sacaco Basin, Peru. Journal of Vertebrate Paleontology 33:709-721.

Muizon C. de 1988. Les vertébrés fossiles de la Formation Pisco (Perou). Troisieme partie: Les odontocètes (Cetacea, Mammalia) du Miocène. Editions Recherche sur les Civilisations 78: 1-244.