Dots in Deep Time

Quill knobs vs. Intermuscular line

2010-09-10T04:40:00.000-07:00

Lately Concavenator has caused quite a buzz among the dinosaur researchers. And there is no doubt that there is a lot to talk about regarding it's phylogenetic position and it's relationship and possible synonymy to Becklespinax. It now seems that the discussion has shifted focus to Concavenators quill knobs .
To give a brief summary (Ortega et al,2010) in their description of Concavenator noted series of small bony bumbs running in a single line on the ulna and proposed that these are homologous to quill knobs. Darren Naish and Mickey Mortimer came independently to the conclusion that instead of quill knobs the structure represents intermuscular line. And indeed looking at the Alligator forelimb musculature the line of knobs fits rather nicely between flexor ulnaris and the extensor carpi radialis brevis:

Image is from Mickey Mortimers blog

However let us not forget our feathered winged friends. If we are going to make conclusions based on muscular reconstruction, then we must also take into account the birdies
And here's a nice comparison modified from an excellent chart done by John Conway.

As you can see Birds simply do not have the large extensor carpi radialis brevis complex of crocodilians and the flexor ulnaris attachment area is above the mid line of the ulna.

So how should we reconstruct the musculature? It's problematic. Especially when we consider the locomotary difference between the two extant animals. Crocodilian with it's terrestrial/aquatic lifestyle, quadrupedality and postural diversity and in the other hand flying bipedal birds with heavily limited wrist motion. I tend to lean on birds due to closer relationship, locked radii&ulnae which would pose limitations to musculature and bipedal locomotion which provides similar pressures for forelimb musculature.

So it seems that the whole intermuscular line hypothesis isn't all that straightforward. In phylogenetic bracketing terms it's level II inference. It might or it might not be intermuscular line but that's depending on muscular reconstruction.

Sketches: Microraptor gui

2010-08-18T06:09:00.000-07:00

Ok one more. I swear I just discovered this one from my WIP folder. Didn't even remember that I had done this quick study of M. gui, but I really like it.

Sketches: sphenosuchians

2010-08-15T12:02:00.000-07:00

Something I did for my finnish paleo blog.
Dibothrosuchus and Pseudohesperosuchus. Not too happy about how Pseudohesperosuchus came out. Sigh, This is a third sketch post in a row. I think I need to find something to write about.

Sketches: adorable and slightly creepy

2010-08-13T09:55:00.000-07:00

And that is why you don't see anurognathids often depicted this way.

Sketches

2010-08-12T12:20:00.000-07:00

I sketch all the time. way too often actually and at times when I really should be doing something else. I was originally thinking of starting another blog just for my sketches, but then I remembered that I have a blog that has remained inactive for far too long now. I think I'll start posting these sketches here. At least it will keep this blog active even when I have nothing smart or interesting to write about.

So here are the first ones. Anurognathus and Platecarpus that was originally done for my 'Platecarpus and its fluke' post. The platecarpus one was supposed to illustrate the facial scalation preserved in LACM 128319, but then I decided to leave it out.

Platecarpus and its fluke

2010-08-12T11:18:00.000-07:00

Platecarpus tympaniticus (LACM 128319) in it's full glory. See high res version here

Paleontology is mostly bare bones, but on occasion we are treated with discovery of exceptional specimen that brings us that much closer on how the animal looked and lived when it was still alive. I love those specimens. To see a skin impression, or halo of feathers, or to see insect in amber and to realise that what you are seeing are details of an animal that once lived and breathed in this planet millions of years ago...it's simply amazing.

This time the treat is a mosasaur. A complete articulated specimen of Platecarpus tympaniticus from famous niobrara chalk formation that preserves possible remains of retina, numerous skin impressions (including parts of the facial scalation), cartilaginous rings that supported the windpipe, possible remains of internal organs, last meal (partially digested fish bones) and partial body outline. Amazing stuff. But what really got peoples attention was the tail.

The tail is distinctly kinked downward in similar fashion that is seen in other extinct marine reptiles like ichthyosaurs and thalattosuchian crocodiles. Not only that but the length pattern of individual vertebral bodies in the tail is typical for animals that have (dun dun dunh!) a two-lobed tail fluke.

Yes indeed, this animal had tail fluke. Now this isn't the first case of mosasaur with such thing to be reported. The first one was Plotosaurus. A very derived form, so the tail fluke in this animals was thought to be anomalous and typical for only this mosasaur. Now Platecarpus is more typical mosasaur indicating that two-lobed tail fluke is far more widely present among mosasaurids.

Furthermore this means that these mosasaurs were far better adapted to swimming than previously thought. Unfortunately we don't know the exact shape of the whole tail fluke. Apparently the outline was possibly present , but was destroyed before the preparator realised that there was soft tissue preserved.

It would be interesting to see how the tail vertebral metrics of mosasaurs match against some ichthyosaurs. Ichthyosaurs have pretty nice fossil record that documents the evolution of aquatic adaptations including the fluke, so comparison between Ichthyosaurs and mosasaurs could shed some light to how far mosasaurids got with this whole fluke thing, and perhaps give an indication of the fluke shape. Should be rather interesting indeed.

Ofcourse the cherry on top of this whole thing is the fact that it was published in PLOS.
Open access and high res photos. Awesome.

Lindgren J, Caldwell MW, Konishi T, Chiappe LM (2010) Convergent Evolution in Aquatic Tetrapods: Insights from an Exceptional Fossil Mosasaur. PLoS ONE 5(8): e11998. doi:10.1371/journal.pone.0011998

vertebrata palasiatica 2009-1973 online

2009-08-09T14:01:00.000-07:00

Issues of Vertebrata Palasiatica from 2009-1973 are now available at IVPP website.

If your chinese has gotten a bit rusty, you can use handy dandy babelfish translator.

It's not perfect but hey, atleast it provides some hilarity.

For example:

Liaoxi Yi County group parrot mouth dragon (bird buttocks item, ceratopsia) new material and stratigraphy significance

Inside nature's giants: Whale and Elephant

2009-07-26T08:13:00.000-07:00

Ever since I heard of this series I have been trying to find some footage of it. Series focusing on functional anatomy of largest modern tetrapods sounded like very novel and very interesting idea.
So there I was searching for some video clips of the series but instead finding mear clips I stumbled upon playlist of two full episodes of it! Yes, some wonderful person has uploaded two episodes to youtube, and after watching those I can't wait to see the other two episodes. It's really interesting , educational and gory, so be warned if you have weak stomach.

first video:

and playlist

NG clip with new pachycephalosaur featured

2009-07-17T09:29:00.000-07:00

The clip starts with talk about Dracorex and headbut theories but towards the end of the clip a new little pachy makes it appearance.
I'm not sure if this is old news but it's certainly first time I have seen mention of this critter.

Richard Prum at skeptics guide to the universe podcast

2009-07-17T07:02:00.000-07:00

Richard Prum appeared recently at the skeptics guide to the universe podcast where he shared hes views on the new Ruben & Quick bird abdominal airsac paper and BAND movement.

You can listen the podcast here .

New in Digimorph: Incisivosaurus

2009-07-15T12:29:00.000-07:00

Ever since the detailed description of Incisivosaurus was published in American museum novitates I have been hoping that this would happen.
And now it has. Incisivosaurus is now featured at Digimorph website. Go and look at everyone's favourite Bugsbunnysaurus in 3d.

http://digimorph.org/specimens/Incisivosaurus_gauthieri/

more old issues of Acta Palaeontologica Polonica available

2009-06-17T10:24:00.000-07:00

It seems that APP old issue archive has expanded back to the year 1980. Some of the individual issues seem to be missing but there's still loads of goodies in there so check it out.

Also, Journal of Anatomy has gone free access.

From Journal of Anatomy website:

"Journal of Anatomy archive - free online!
For free access to the full archive of Journal of Anatomy from volume 1, issue 1 (1867) up to 2005 click here. Access the most recent articles from 1997 to the latest OnlineEarly articles online. All issues more than two years old are made free."

Pterosaur goodies

2009-06-08T07:18:00.000-07:00

Yes, another expedition to youtube has provided results. Here is very nice animation of Anhanguera taking of via quadrupedal launch, as suggested by Michael Habib in a paper that I still have not acquired nor read (oh the shaaame).

It look nice but I would think that when the animation is in the "Launch" position the animal would already be in the air, but regardless it's very nice animation and great illustration how quadrupedal launch works.

More goodies. I just discovered website called Pterosaur net . It's an excellent website with some nice articles, like pterosaur myths by Darren Naish, pterosaur locomotion by Mark Witton, restoring pterosaurs by John Conway and sections for pterosaur origins, ecology and popular culture. There's also small gallery of some of the most beautiful pterosaur artwork I have ever seen. However as great as all of that is, I must confess my favourite section of the website is the gallery of famous pterosaur fossils. Beautiful photos of classic pterosaur specimens and new Tischlinger UV treats.

Putting Brachiosaurus into perspective

2009-05-23T16:28:00.000-07:00

I was just browsing trough the google image search trying to find some reference photos and came across this neat photo.(Photo from here)

I bet those folks at SV-POW would love this....sigh..those Brachiosaur fanboys.
But seriously, it really does not get much cooler than this, although I kinda feel sorry for the Diplodocus down below.

Darwinius masillae hubub

2009-05-20T01:49:00.000-07:00

The discovery of the new messel primate, Darwinius masillae, has brought out unprecedented media storm. The photos of this new discovery are popping out everywhere and the titles of the news repeatedly shout out the most annoying and useless of terms, missing link. Don't get me wrong, I'm all for publishing new and exciting discoveries (Which this is, among being one of the most beautiful fossil ever found) in the mainstream media, all I'm asking is, do it right and get your facts straight!

Here's a fun little party game. Can you count the facepalm moments in this news clip?

Puijila darwini

2009-04-22T15:05:00.000-07:00

PaleoArt #4

2009-03-21T13:04:00.000-07:00

As you might have noticed this blog has been on hiatus for a while. It all started from week long intensive course on skeletal anatomy and more recently I have been occupied by sediments. Luckily I have escaped the dungeons of sediment laboratory to bring you teh ultimate Tianyulong confuciusi skeletal.

Some old sauropod papers available at Biodiversity Heritage library

2009-03-01T05:12:00.000-08:00

Did some paper digging today at the BHL website and found some interesting stuff that I though I would share.
Below is author, date, tittle, link to preview page and pdf download link.
BHL will host the download link 30 days.

Young, 1975
Brachiosaurus: the biggest dinosaur of them all

http://biodiversitylibrary.org/page/2831990
http://www.biodiversitylibrary.org/pdf1/000249100021272.pdf

Jensen, 1987
New Brachiosaur material from the late jurassic of utah and colorado

http://biodiversitylibrary.org/name/Brachiosaurus_altithorax
http://www.biodiversitylibrary.org/pdf1/000249200035774.pdf

Holland, 1915
A New Species of Apatosaurus (A. louisae)

http://biodiversitylibrary.org/page/9967578
http://www.biodiversitylibrary.org/pdf1/000249300038133.pdf

Gilmore,1933
On a Newly Mounted Skeleton of Diplodocus in the United States National Museum

http://biodiversitylibrary.org/page/7616479
http://www.biodiversitylibrary.org/pdf1/000249400032577.pdf

Art Evolved: it's alive!

2009-03-01T02:58:00.000-08:00

Yes, it's the hot new paleo-art blog that everyone is talking about (Well at least they SHOULD be talking about).

See the world famous ceratopsian gallery here.

When I get bored

2009-02-28T16:17:00.000-08:00

This happens:

Learn to recognize symptoms early on.

1.5 MYO Hominin footprints from Ileret, Kenya

2009-02-26T13:56:00.000-08:00

New in Science!

Matthew R. Bennett et al., “Early Hominin Foot Morphology Based on 1.5-Million-Year-Old Footprints from Ileret, Kenya,” Science 323, no. 5918 (February 27, 2009): 1197-1201, doi:10.1126/science.1168132.

Abstract:

Hominin footprints offer evidence about gait and foot shape,but their scarcity, combined with an inadequate hominin fossilrecord, hampers research on the evolution of the human gait.Here, we report hominin footprints in two sedimentary layersdated at 1.51 to 1.53 million years ago (Ma) at Ileret, Kenya,providing the oldest evidence of an essentially modern human–likefoot anatomy, with a relatively adducted hallux, medial longitudinalarch, and medial weight transfer before push-off. The size ofthe Ileret footprints is consistent with stature and body massestimates for Homo ergaster/erectus, and these prints are alsomorphologically distinct from the 3.75-million-year-old footprintsat Laetoli, Tanzania. The Ileret prints show that by 1.5 Ma,hominins had evolved an essentially modern human foot functionand style of bipedal locomotion.

who are I?

2009-02-25T11:51:00.000-08:00

Since exams keep me quite busy I thought I would rely on the traditional way to deal with blog hiatus.

Yes...it is time for skull trivia.

Probably way to easy but it's the only one I got handy at the moment.

Miragaia: the freakishly cool long necked stegosaur

2009-02-25T09:51:00.000-08:00

You know, paleontological community is not making my geology studies any easier.
I have enviromental geology exam tommorrow and while I'm reading calmly all that super interesting exam material what happens? They go and publish something freakishly awesome like Miragaia.

You can read the paper here.

The mighty Physeter

2009-02-22T15:15:00.000-08:00

I got slightly derailed from lemurs, which is something that I would never ever usually do
*Cough*cough*.

Whales got me . All this began when I was browsing books at our local bookshop. I came across this book called "Whales dolphins and seals: a field guide to the mammals of the world".
It looked interesting and was cheap enough for my student budget so I decided to buy it, and oh boy I'm happy I did. It covers all of the marine mammals of the world, covering whales, dolphins, seals, manatees, polar bear and marine otter. every taxa is covered with fieldguide fashion and accompanied by gorgeous illustrations.

Blasted be my damn ignorance I had no idea that such diversity of marine mammals existed.
Quoting Darwin, my mind is chaos of delight.

So I have basically been reading all the literature about fossil whales I have been able to collect. Among all that I have tried to learn the whale anatomy which lead to me to redraw Sperm whale skeleton from old plate I discovered from the web

*I love those old plates but that's a ramble for another day.

(Click for larger view)

I love to draw skeletals like this. Sure it's tedious at times but I for one have found it to be absolutely the most efficient way to learn skeletal anatomy. If I draw it I pretty much remember it. It's also excellent way to notice things that you might not make any note of just by "superficial" look of the skeleton.
For example while I was tracing the caudal vertebrae I made notice of small but noticeable foramina on the mid caudals. I have no idea what they are for, but if someone does please let me know.

Dinosaurs of the Gobi

2009-02-19T07:36:00.000-08:00

Where did these kind of documentaries go?
I sure miss the times when there was actual content in the dino docs rather than just 3D dino screaming.

Playlist

Weirdest of lemurs: Megaladapidae

2009-02-17T08:46:00.000-08:00

And so we get back to the lemurs...which we actually never left.

*Unfortunately this will be a shortie simply because I wasn't able to find all that much material on these guys. it seems that most of the recent papers deal with Archaeolemurids and Palaeopropithecids and poor Megaladapids have received only limited ammounts of attention.

It could easily be said that Megaladapids are the posterboys of extinct Madagascan lemurs.
Their markedly elongated large and massive skull with large canines makes them look spectacularly prehistoric, and so perhaps their popularity is not all too unexpected.

Megaladapidae is monogeneric family that includes three species (Megaladapis madagascariensis, M. edwardsi and M. grandidieri). All of them exceed the body size of largest lemur living today (Indri indri 13 kg). Smallest species, M. madagascariensis, reaching weight of 38 kg while largest, M. edwardsi achieved mass of 78 kg.

Skull is obviously large compared to body size. The tapering snout and large mandibular apron makes the silhouette of the skull somewhat reminiscent of some basal perissodactyl.
Stout limbs with relatively large hands and feet plus moderately curved and long phalanges provide support for the idea that Megaladapis was mainly arboreal creature, although perhaps not the most agile of climbers. The absence of upper incisors, well developed molar shearing crests and microwear point to folivorous diet.

Arboreal habit with folivorous diet paint a picture of somewhat (Dunh dunh dunh!) koala like animal, that employs slow vertical climbing to reach those delicious young leaves.

The peculiar condition of total reduction of upper incisors is shared with sportive lemurs of today and this together with other morphological features have been used to demonstrate close relationship between sportive lemurs (Lepilemuridae) and megaladapids. However more recent analysis based on subfossil dna samples, place Megaladapidae as sister group to Lemuridae (Karanth et al, 2005).

Megaladapis to survived shockingly recent times, latest occurrences being dated to AD 1280-1420 (Burney et al,2004).

References:

Burney DA, Burney LP, Godfrey LR, et al. A chronology for late prehistoric Madagascar. Journal of Human Evolution. 2004;47(1-2):25-63.

Hartwig WC. The Primate Fossil Record. 1st ed. Cambridge University Press; 2008.

Karanth KP, Delefosse T, Rakotosamimanana B, Parsons TJ, Yoder AD. Ancient DNA from giant extinct lemurs confirms single origin of Malagasy primates. Proceedings of the National Academy of Sciences of the United States of America. 2005;102(14):5090-5095.

Rafferty K.L.,Teaford M.F., Jungers W.L. Molar microwear of subfossil lemurs: improving the resolution of dietary inferences. Journal of Human Evolution. 2002;43:645-657.

double canines of doom

2009-02-15T14:13:00.000-08:00

I came across this bit of shear awesomeness while I was reading about the giant lemurs.
It belongs to fork-marked lemur (Phaner furcifer) which is small lemur (300-500 g) that feeds mainly on tree gum. But look at those teeth! The first one if canine alright but second is the first premolar trying to act all tough and canine looking. If I'm not terribly mistaken the lower canine is not canine either but again the first premolar.

By the way those who are beginning to think that I have unholy fixation to skulls.....I think you're right.

Next up :
(if I don't get something short and snappy to blog about in the meanwhile) koala lemurs and sloth lemurs.

References:

Tattersall, Ian. Schwartz, Jeffrey H. 1974
Craniodental morphology and the systematics of the Malagasy lemurs (Primates, Prosimii). Anthropological papers of the AMNH ; v. 52, pt. 3

Weirdest of lemurs: Archaeolemuridae

2009-02-15T05:43:00.000-08:00

Last spring I had a chance to see some fragmentary subfossil remains discovered from Pleistocene/Holocene deposits of Madagascar. Although fragmentary, many of the bones were readily identifiable, especially the humongous distal end of bird metatarsal belonging to Aepyornis.

In my opinion there is something quite special about subfossil animals.
Perhaps it's the fact that they were still around literally blink of an eye ago, and partly because often the animals were large to gigantic in size and thus "prehistoric" by nature.

And what's there not to like about Madagascan megafauna? It's all full of goodies like:

-Humongous Aepyornithid birds (Mullerornis spp, Aepyornis spp.)
-Giant tortoises (Dipsochelys spp.)
-Robust Horned crocodiles (Voay robustus)
-Dwarf Hippos (Hippopotamus spp.)
-Giant examples of still existing madagascan animals, like Giant Aye Aye (Diabenton robustus) and giant fossa (Cryptoprocta spalae) among them.

There would be so much stuff to talk about (and I hope I'll find time to do so in the future)
, but now I want to tell you about the most famous and charismatic animals of Madagascan megafauna, the giant lemurs.

There are three families that are often labeled under the general term "Madagascan giant lemurs".

These are the monkey lemurs (Archaeolemuridae), koala lemurs (Megaladapidae) and sloth lemurs (Palaeopropithecidae).

Contrary to what people might think (Well..I used to think so) they do not form one single monophyletic group, but are actually related to different lemur lineages as we shall see later on.

Today I'll be serving you the Monkey lemurs.

Archaeolemuridae contains 2 genera and 3 species (Archaeolemur majori, Archaolemur edwardsi and Hadropithecus stenognathus).
Largest of these, Hadropithecus stenognagthus, reached weight of about 27 kg while Archaeolemur was about the size of modern Indri at 15 kg.
These guys are not called monkey lemurs for no reason. Their flat face, bilophodont molars and the incomplete material known at the time, lead the first workers to misidentify the remains as anthropoids. This was soon after corrected by the discovery of more complete remains that revealed their true identity as one of the more unusual lemurs ever discovered.

These lemurs were also among the brainiest of their kin approaching body/brain ratio of Haplorrhines (Ryan et al, 2008).

The detailed morphology of postcranial remains show that archaeolemurids had specialisations for terrestrial locomotion. Limb proportions seems to imitate those of terrestrial old world monkeys (Jungers et al, 2005). The skeleton skeleton lacks any adaptations for leaping and the semicircular canals indicate reduction in agility (Tattersall, 2008). The carpal tunnel seems to be shallow, as inferred from carpal bones, and short and less curved metacarpals corroborate the interpertation that Archaeolemurids preferred land over trees (Lemelin et al, 2008).

Life reconstruction of Hadropithecus stenognathus by Stephen Nash from (Tattersall,2008)

All in all monkey lemurs seem to parallel those of more terrestrial old world monkeys, but still it would be mistake to say that they are identical in habits.

While both Archeolemur and Hadropithecus seems to have been able to process hard food items the anatomical differences show that there must have been divergence in food processing and diet between the two taxa. One of the more noticeable differences between Hadropithecus and Archaeolemur is that while the latter had very large bugs bunny incisors, it's larger relative Hadropithecus went another direction and reduced the size of incisors.

Skulls of Archaeolemur majori (on the left) and Hadropithecus stenognathus (on the right)

Another cool feature seen in Archaeolemur is the unique shearing blade formed by premolars. Obviously such shearing blades could be utilized for consuming small animal prey and such interpertation seems to have been confirmed from fecal pellets (supposedly belonging to young Archaeolemur cf. edwardsi) that contained small animal bones and fragments of gastropod shells (Godfrey et al, 2005). The shearing dentition is party present in Hadropithecus but seems to be limited to the first two premolars.

Based on craniodental morphologies archaeolemurs have been thought to be sister taxon to clade that includes Indrids and sloth lemurs (Palaeopropithecidae). This was subsequently confirmed by (Orlando et al 2008) via phylogenetic analysis based on DNA extracted from subfossil samples.

Aleast Archaeolemur seems to have been able to survive quite long, youngest remains dating to early second millenia AD. (Godfrey et al, 2005).

Folklores of Madagascar still tell tales about terrestrial lemur called Kidoky(Godfrey et al, 2005), and it's more than tempting to think that these stories are refering to Archaeolemurid but unfortunately we can never be sure.

References:

Godfrey LR, Semprebon GM, Schwartz GT, et al. New Insights into Old Lemurs: The Trophic Adaptations of the Archaeolemuridae. International Journal of Primatology. 2005;26(4):825-854.

Godfrey L, Jungers W, Burney D, et al. New discoveries of skeletal elements of Hadropithecus stenognathus from Andrahomana Cave, southeastern Madagascar. Journal of Human Evolution. 2006;51(4):395-410.

Jungers W, Lemelin P, Godfrey L, et al. The hands and feet of Archaeolemur: metrical affinities and their functional significance. Journal of Human Evolution. 2005;49(1):36-55.

Lemelin P, Hamrick MW, Richmond BG, et al. New hand bones of Hadropithecus stenognathus: implications for the paleobiology of the Archaeolemuridae. Journal of Human Evolution. 2008;54(3):405-413.

Orlando L, Calvignac S, Schnebelen C, et al. DNA from extinct giant lemurs links archaeolemurids to extant indriids. BMC Evol Biol. . 2008;8:121

Ryan TM, Burney DA, Godfrey LR, et al. A reconstruction of the Vienna skull of Hadropithecus stenognathus. Proceedings of the National Academy of Sciences. 2008;105(31):10699-10702.

Tattersall I. Reconstruction of an extraordinary extinct primate from Madagascar. Proceedings of the National Academy of Sciences. 2008;105(31):10639-10640.

Well cooked coot

2009-02-14T09:30:00.000-08:00

I thought I would follow the blue lake rhino post with another exceptional case of preservation.

The external mould and some microscopic detail from (Channing et al,2005)

This external mould of probably Pleistocene-Holocene American coot (Fulica americana) was discovered from extinct hot springs deposit at Yellowstone national park.
The animal died either at the hot springs vent pool OR in associated pool and was crusted by silica due to rapid microbial activity.
The specimen is preserved in amazing detail, showing the fleshy cranial crest, and even the microscopic detail of the plumage.

References:

Channing A, Schweitzer MH, Horner JR, McEneaney T. A silicified bird from Quaternary hot spring deposits. Proceedings of the Royal Society B: Biological
Sciences. 2005;272(1566):905-911.

Rhino among the pillows

2009-02-13T16:35:00.000-08:00

in summer of 1935 three people were hiking near blue lake Washington, when they came across small cave on the basalt cliff. On the floor of this small cavern there was bone fragments scattered all around and among them fragments of jaw with teeth still in place. Fortunately enough these people found their discovery interesting enough to collect some of the bones, and bring them back to specialist, who could tell them to what kind of animal did these remains belong to. News of this find reached the ears of Mr. Beck who together with hes assistant, Mr. Freschette visited the strange cavern. It wasn't all that big, approximately 80 cm in diameter and some 1.8 m in length with strange pipe like extensions on the side of main cavity. From these extensions Mr. Freschette was able to collect few very fragmented bones. The jaw and the newly excavated remains were sent for identification to Chester Stock who came to conclusion that remains belonged to Aphelops kind of rhinoceros (Later identified as common late Oligocene to Miocene rhino Diceratherium). Bit by bit it became more and more clear exactly what this cavity in the basalt cliff was, and in hes paper about the discovery, Beck proposed that it might represent mould of extinct rhinoceros.

When cast was made of the cavity there were no room for doubt. The animal was lying on it's left side with legs sticking out, as is typical for dead animal in rigor mortis condition. The body is obviously bloated in and very little detail can be extracted from it, except possible skin folds in the neck.

Drawing of the mold and life reconstruction of blue lake rhino (Chappel et al, 1951)

So how the heck did this rhino get trapped in basalt?

Well underneath the basalt strata there was section of fine sandy sediment indicating water environment perhaps a lake. Above this sediment layer there is ellipsoid pillow lavas that forms the walls of the cavity, indicating that lava had contact with water. Moving on up the basalt turns in to massive in form indicating a lava flow with no contact with water.

Bloated body and rigor mortis position indicates that the rhino had been dead for a while, and was possibly floating on water. When lava flow came in contact with water it formed pillow lavas that wre cool enough to not to destroy the rhino carcass but still plastic enough to preserve the form of the rhino. Pillow lavas piled over the rhino preserving it's form and when the rhino was covered, another lava flow came and entombed the pillow lavas.

Cool and weird case of preservation, but what I would really like to know is the reaction when the hikers learned that they climbed into ancient rhinoceros. ;)

References:

CHAPPELL WM, DURHAM JW, SAVAGE DE. MOLD OF A RHINOCEROS IN BASALT, LOWER GRAND COULEE, WASHINGTON. Geological Society of America Bulletin. 1951;62(8):907-918.

Putting Mrs. Ples under stress

2009-02-13T16:00:00.000-08:00

SD: High-tech Tests Allow Anthropologists To Track Ancient Hominids Across The Landscape

2009-02-13T14:51:00.000-08:00

Here's the link to Science Daily article.

Interesting bit from the text:

"Other intriguing research under way by Sponheimer and his colleagues hints that some female australopithecines, including members of the Paranthropus genus, died in different geographic areas than where they were born. The researchers are comparing such data to social patterns of chimpanzees, in which females generally migrate away from their original ranges and move into new areas -- the opposite of behavior charted in most other primates, said Sponheimer."

Paleoart #3

2009-02-13T14:26:00.000-08:00

Yet another of those lateral view head profiles. I wish had more time and inspiration to do more "complete" paleoart.

Anyways, those who didn't recognize this guy already it's the recently described South American abelisaurid, Skorpiovenator bustingorryi. Beautiful specimen. It's rather interesting that usually when there's articulated abelisaurid specimen they're found in very similar position and they lack most of their tails. Could be that because tail "sticks out" it's eaten away by erosion. Interesting nonetheless.

Clips from national geographic new evolution series

2009-02-13T03:00:00.000-08:00

Not bad but I must admit there are parts that made me cringe.
Rodhocetus sems to have unique fusion of occipital and atlas in the 3d skeleton model. ;)

Bipes biporus in action

2009-02-13T02:57:00.000-08:00

(I can't embed the video because embedding option has been disabled by the youtube user, BUT you can still see the video here.)

This thing is surreal. I must admit that when I first saw photo of one I was sure it was photoshop creation. It looks like bizarre mix of mole, armadillo and worm lizard.
Bipes or ajolote lizard, is basalmost genus of the living Amphisbaenians, and unlike all of it's living relatives (as you can clearly see) it retains fully functional forelimbs. It also has vestigial hindlimbs presented by femora but these are small and do not manifest externally. Like most of it's relatives, Ajolote is fossorial in habit and employs unique combination of forelimb+headfirst digging using it's powerful forelimbs and claws to dig away the dirt kind of like Moles. As can be expected it's diets consist invertebrate prey with ants and termites being the most preferred food item (Kearney, 2003).

Oh, and it has a wicked skull:

References:

Nathan J. Kley and Maureen Kearney.
Chapter 17 : Adaptations for digging and burrowing,
in Hall BK. Fins into Limbs: Evolution, Development and Transformation. New edition. Chicago University Press; 2007.

Maureen Kearney. Diet in the Amphisbaenian Bipes biporus. Journal of Herpetology. 2003;37(2):404-408.

SSE Darwin Birthday Card

2009-02-12T08:27:00.000-08:00

*1:18 And that is how you do it in Finnish style. :)
Dangit, we should have done something like that on our university.

Standford university lecture series: Darwins legacy

2009-02-12T08:10:00.001-08:00

Youtube playlist here.

Aldabra

2009-02-12T07:40:00.000-08:00

Aldabra is slightly raised coral atoll in the Indian ocean, some 400 km northwest from northern coast of Madagascar. When it comes to atolls, Aldabra is somewhat unique not
only because of it's current fauna, but also for preserving terrestrial sedimentary record which can tell us tales about aldabras recent past.
Admittedly this record is not very extensive. Stratigraphy of Aldabra shows fluctuation between limestone, and terrestrial sediments which accumulated to
cavities that erosion had carved into the limestone.

These fluctuations of marine and terrestrial sediments tell quite clear tale, that in the past there were periods of time when Aldabra was swallowed by the sea and then re-emerged again from the waves. Considering the Pleistocene age of these sediments the most likely culprit for these sea level changes was the alternating periods of glacials and interglacials.

So what is in these sediments you may ask? well luckily enough we do have fossils. Terrestrial gastropods are abundant but there is also vertebrates,
including several different lizards (Geckos,iguanids and skinks are represented). Nile crocodile was there and so was small, now extinct species of
crocodile, Aldabrasuchus. Few genera of birds are recognized including gadfly petrel (Pterodroma) extinct anatid (Aldabranas) and the White-throated Rail (Dryolimnas)
which is still with us today.

And then there is the ever famous giant tortoise (Dipsochelys). Dipsochelys has been found from the very earliest of the terrestrial sediments, and it seems to have always made it's way to Aldabra every time when the atoll was raised from the sea, and so it has been suggested that tortoises had colonized Aldabra at least on three different occasions.

Today Aldabra has the largest population of giant tortoises anywhere on this planet with 85 000 tortoises spread over 155.4 km² constituting largest biomass
of any grazing animal (21 tons of turtle per km²). But this wasn't always so.

during seventeenth century, once widespread species found all over of Indian ocean was ravaged by heavy collecting of sailors and colonials, who probably
found these tortoises just as tasty as Galapagos ones. Dipsochelys was rapidly exterminated from majority of it's past range. Aldabra was mostly saved probably due to it's rather isolated location.

in 1874 several important scientist of the day, Charles Darwin among them, sent petition to the governor of Mauritius to protect Aldabra and it's remaining
population of giant tortoises. At the beginning of nineteenth century the population numbers were in few hundreds, but thanks to protection of this unique
habitat, during following decades the population recovered and grew to amazing numbers we see today.

References:

Photo from animal diversity website

Dupre A, Devaux B, Bonin F. Turtles of the World. A & C Black Publishers Ltd; 2007.

Stoddart DR, Savy S. Aldabra: Island of Giant Tortoises. Ambio. 1983;12(3/4):180-185.

Taylor JD, Braithwaite CJR, Peake JF, Arnold EN. Terrestrial Faunas and Habitats of Aldabra During the Late Pleistocene. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences (1934-1990). 1979;286(1011):47-66.

Happy birthday Mr. Darwin

2009-02-12T00:52:00.000-08:00

200 years and still partying like it's 1859.

Neofelis diardi: First by genetics, then by pelt and now by skull

2009-02-11T02:29:00.000-08:00

Diard's clouded leopard got quite a bit of media attention in 2006 when it was shown by genetics and pelt morphometrics that the population at Sumatra and Borneo differed enough from mainland population to warrant new species status.
(See excellent post about this by Darren Naish HERE)

(Christiansen, 2008) strengthens this distinction even further by performing morphometric analysis to 25 skulls of N. diardi and 17 skulls of N. nebulosa. The results show conclusively that the variation between two population goes way further than that seen between subspecies of pantherine cats.

Among other features, N. diardi differed from N. nebulosa by having longer and flatter upper canine, narrower palate between canines but wider across pterygoids, thicker upper carnassials across the paracone, larger lower premolar 4 and smaller lower premolar 3.

Per Christiansen has previously made valuable work noting convergent sabertooth characteristics seen in Neofelis (Christiansen, 2006, 2008b) . Especially interesting is the grand
similarity between Neofelis and basal Machairodont cat, Paramachairodus ogygia.
One of the more impressive manifestations of this convergence is that Neofelis has the largest gape of any cat. It can open it's jaws up to 85 degrees.

(Adjacent picture is from (Salesa et al, 2005).

I find it very intriguing that Diard's Clouded leopard goes further in in these sabertooth convergences than it's mainland relative and I can't help but
wonder what drives such development. The burning question is how does this small basal Pantherine cat make it's kills?

Unfortunately we know pitifully little about how clouded leopards hunt and kill in nature (Not to mention the differences between N. Diardi and N. nebulosa on this matter).
What is knows is that it's diet consist of variety of arboreal prey (Monkeys etc.) but apparently it's also able to subdue prey of it's own size or larger
like muntjak, bearded pig and hog deer (Christiansen, 2006).
Odly enough reports suggest that instead of attacking the throat, clouded leopard uses powerful nape bite to subdue their prey (Christiansen, 2006).

Risking those long canines like that seems counter intuitive to me, but nature hardly holds any value what derived African ape thinks about what is and what is not counter intuitive.

References:

Christiansen P. 2006. Sabertooth characters in the clouded leopard (Neofelis nebulosa Griffiths 1821). Journal of Morphology.267(10):1186-1198.

Per Christiansen (2008). Species distinction and evolutionary differences in the clouded leopard (Neofelis nebulosa) and Diard's clouded leopard (Neofelis diardi) Journal of Mammalogy, 89 (6), 1435-1446

Christiansen P. 2008b Evolutionary convergence of primitive sabertooth craniomandibular morphology: the clouded leopard ( Neofelis nebulosa ) and Paramachairodus ogygia compared. Journal of Mammalian Evolution. 15(3):155-179.

Salesa MJ, Anton M, Turner A, Morales J. 2005. Aspects of the functional morphology in the cranial and cervical skeleton of the sabre-toothed cat Paramachairodus ogygia (Kaup, 1832) (Felidae, Machairodontinae) from the Late Miocene of Spain: implications for the origins of the machairodont killing bite. Zoological Journal of the Linnean Society. 144(3):363-377.

Lady of the La Brea

2009-02-10T01:52:00.000-08:00

In January 1914 staff of Museum of history, Science and Art of Los Angeles started to work on new excavation pit at famous site of rancho la brea.
They discovered (as was expected) hundrends of fossils of mammals. There, at the depth of 2 m , mingled among fossil animal remains, they discovered upper jaw of a human. Further excavation churned out rest of the skull and some postcranial remains scattered quite widely over the excavation area. The remains belonged to one individual. Female about 25 year old .

I don't know why the discovery of human remains from tar pit came such a surprise to me. I guess it's just the naive thought that the remains discovered from la brea belonged to "stupid" mammals that were unaware of the danger.

Although the human remains were discovered from la brea, it is interesting to note that the associated fauna lacked many of the classic animals like Dire wolf, sloths and saber toothed cats. Indeed the excavated fauna was very much like we see today, indicating that the human remains discovered from pit 10 are relatively recent of origin, perhaps latest Pleistocene.

Interestingly there was one quite iconic la brean animal discovered from pit 10.

The great Teratorn.

Think about that.

References:

Merriam JC. PRELIMINARY REPORT ON THE DISCOVERY OF HUMAN REMAINS IN AN ASPHALT DEPOSIT AT RANCHO LA BREA. 1914.

Kroeber AL. The Rancho La Brea Skull. American Antiquity. 1962;27(3):416-417.

Kolponomos: the bear that wanted to live in the sea

2009-02-08T12:46:00.000-08:00

Ok, this is one of those creatures that gave me "What the heck is this and why haven't I heard about it before!" moments.

Kolponomos is ursid known from early Miocene near marine sediments of Washington and Oregon.
It was first described by Stirton in 1960 based on partial cranium discovered from Clallam county, Washington.
He named this find as Kolponomos clallamensis* and placed it into family Procyonidae (Raccoons etc.)
Additional material and new species, Kolponomos newportensis, was described by (Tedford et al 1994).
Based on phylogenetic analysis (Tedford et al 1994) found Kolponomos to be ursid and not only that, but sister group to basal pinniped Enaliarctos.

*I don't know the etymology but if someone does please tell me.

Skull reconstruction of Kolponomos newportensis
(Redrawn from Tedford et al 1994)
with sillhouette of rigth upper post canine dentition

Now look at that thing! I don't know where to start!
Skull is obviously very robust. The mandibular symphysis is very deep, canines and incisors are enlarged and the post canine teeth are large and wide.
Nasal opening is retracted, Infraorbital foramen (Hole right in the front of the eye socket) is large and so are the mandibles mental foramina.
All of this and the discovery of bones from near shore sediments would indicate diet and mode of life similar to sea otter (Enhydra) which dines on marine invertebrates (Mussels etc.) Interestingly the teeth are well worn in all known specimens indicating that there was perhaps sediment among it's food creating additional wear to the teeth.
The large infraorbital and mental foramina would indicate thick tactile lips with perhaps long vibrassae (Tedford et al 1994).
Interestingly mastoid processes (The large downward projection behind mandibular joint) is enlarged in similar manner like those of sabertoothed cats, indicating powerful neck muscles for flexing the head downwards. What little is known of the postcrania seems to indicate that despite of these adaptations Kolponomos doesn't seem all that developed swimmer, perhaps no more better than brown bears are today.

What and extraordinary animal and yet we know so regrettably little about it.
Sigh, sometimes paleontology is so frustrating.

And that is it folks! I won't promise anything but there are things like Diard's clouded leopard and fauna of Aldabra atoll moving about my brain, so perhaps I'll write about them somewhere in near future.

References:

Tedford RH, Barnes LG, Ray CE. The early Miocene littoral ursoid carnivoran Kolponomos: systematics and mode of life. Contributions in marine mammal paleontology honoring Frank C. Whitmore, Jr; Proceedings of the San Diego Society of Natural History. 1994, No. 29:11–32.

Heron fishing with bait

2009-02-08T06:00:00.000-08:00

Another youtube discovery.

I dream of digital museum

2009-02-07T15:10:00.000-08:00

This recent news about digitalizing Lucy's remains is perhaps one of the more invigorating news for some time, because it brings up a trend that has been on it's way for some time now, and that is the digitalizing of fossil specimens. We already have constantly developing databases like MorphoBrowser, Paleoview and Digimorph which gives ANY person with Internet access to see remains of modern and ancient beasts in 3d models. The ability to turn and roll or to watch digital dissection of the actual specimens....oh I can't emphasise enough how much these websites have extended my knowledge on animal morphology.

I dream of times when 3d scanning is included on the procedure of cataloging new specimens.
I dream of times when specimens are not only available in some dark museum vaults but accessible to anyone. I dream of times when there's 3d prototyper printer in every major university and all you need to do to access copy of the specimen is to download the scan data, inputting the data to prototyper and voila! You got physical model of fossil specimen on your hands. No damaging casting to unique specimens and endless supply of copies from scan data.

I can only dream that there's something like that in the future. It's easy to dream.
Dreams have no budget nor technological limitations.

Lucy is a good start...let us hope that many more fossils will follow Lucy's example into digital realm.

David Attenborough on Darwin and birds of paradise

2009-02-07T13:05:00.000-08:00

The most unusual hyaenid

2009-02-07T07:08:00.000-08:00

When people usually think of hyenas they tend to think about the brutal predator of African savanna, spotted hyena, with blood stained heads in a feeding frenzy making that creepy creepy laughing sound. That's not all that surprising since almost without exception every nature documentary about African wildlife features spotted hyenas and their antagonistic relationship with lions. Few docs show brown hyena but I have yet to see documentary that features either striped hyena or the aardwolf, latter of which will be the topic of this post.

At first glance it really is hard to believe that it has anything to do with it's brutish cousins. aardwolf (Proteles cristatus) is the smallest living hyaenid reaching 8-10 kg in weight.

It's small stature, big ears and big eyes makes it look more a kin to a viverrid than a hyena and at first glance there's nothing especially weird about it.

The real weirdness starts from it's skull.

First thing that is inherently obvious is the extreme reduction of it's post canine teeth. Unusual in contrast to other living hyenids which are infamous for their large bone cracking dentition. Palate is extremely wide all the way trough giving it quadrangle shape. The lower jaw is anteriorly expanded and spade like in form, quite like that of the young warthog (Kingdon, 1988).

The large frontal sinuses, that are so characteristic for hyaenids from all the way from Miocene Ictitherium to modern hyenas, are very reduced in aardwolf. To me this seems to be paedomorphic state since in spotted hyena the frontal sinuses enlarge ontogenically (Joeckel,1998).

These extreme adaptations reflect aardwolves specialised diet which almost entirely consists nothing but termites. On few instances small vertebrate prey (Small reptiles,rodents) have been observed from stomach contents and on one occasion some scavenged carrion was reported. Termites are captured via tongue and sticky saliva. Due to obvious lack of any ”tools” for cracking into termite mound aardwolves diet is limited to termite species that forage in the open. Species of harvester ants (Trinervimites, Hodotermes) are preferred menu.

It seems that such extreme specialisation pays off. There's very little competition since pangolins and other ant eaters seem to avoid aardwolf's preferred prey item.

The termites are extremely nutritious, rich in fat and protein. Well fed aardwolf doesn't need to feed soon after and usually remains in it's den couple of days doing apparently nothing else than resting and occasionally sun bathing in the morning sun.

Unfortunately aardwolves fossil record is pretty scanty. Fossils from famous pleistocene sites suchs as kromdraai, swartkrans and bolts farm have provided remains of Proteles. Most occasions specimens are indistinguishable from modern species (Proteles cristata) but one apparently larger and more primitive species has been named from swartkrans and kromdraai, Proteles amplidenta (Gingerich 1974, Werdelin&Solounias 1991).

Aardwolves extreme specialisations bring obvious challenges to determining it's systematic position.

(Werdelin & Solounias 1991) Found it to be closest to Plioviverrops, which is one of the more basal fossil hyaenids knows. This would put aardwolf's divergence somewhere around 20 MY. However the lack of Proteles fossils older than pleistocene would indicate younger divergence date (Werdelin&Solounias,1991).

The younger date is corroborated by recent study on molecular systematics of hyaenidae by (Koepfli et al. 2006). Based on molecular clock estimates they proposed divergence somewhere around 10.6 MYA.This would be in late Miocene and (Koepfli et al. 2006) go on to suggest that Proteles might share close relationship with Lycyaena-Chasmaporthetes* lineage.

(*Chasmaportetes is genus of hyena ranging from late Miocene to Pleistocene. It is commonly referred to running hyena dues to it's longer limbs which suggest more cursorial way of life. It's also the only hyena to ever to cross the landbridge into North American continent.)

What is generally accepted is that Aardwolf is the most basal living hyaenid and darn weird one to.

*Finnished just in time to see the last episode of Life in Cold Blood. yay!

References:

Images from IUCN Hyaena Specialist Group Website

Kingdon J. East African Mammals: An Atlas of Evolution in Africa, Volume 3, Part A: Carnivores. University Of Chicago Press; 1988.

Joeckel RM. Unique Frontal Sinuses in Fossil and Living Hyaenidae (Mammalia, Carnivora): Description and Interpretation. Journal of Vertebrate Paleontology. 1998;18(3):627-639.

Koepfli K, Jenks SM, Eizirik E, et al. Molecular systematics of the Hyaenidae: Relationships of a relictual lineage resolved by a molecular supermatrix. Molecular Phylogenetics and Evolution. 2006;38(3):603-620.

Gingerich PD. Proteles cristatus (Hyaenidae, Carnivora) from the Pleistocene of South Africa, with a note on tooth replacement in the aardwolf. Annals of the Transvaal Museum. 1974;29:49-55.

Werdelin L, Solounias N. The Hyaenidae: Taxonomy, Systematics and Evolution. Fossils and Strata. 1991;(30):1-104.

New paleoart blog event is evolving

2009-02-07T00:21:00.000-08:00

ART Evolved: Life's Time Capsule.

See details here.

Lucy's jaw in 3d

2009-02-06T09:10:00.000-08:00

Lucy needs no introduction.

Birds Have Theropod wings

2009-02-05T13:48:00.000-08:00

Interesting new study published in Paleobiology. The authors of this paper tracked morphological character changes in forelimb+pectoral girdle trough theropod evolution. The pattern that emerges shows three distinct punctuations where number of character changes is higher than the normal trend. These punctuations occur in Tenanurans, Eumaniraptorans and Ornithothoraces.

Noticed it yet? Aves is not among the punctuations. Indeed between Eumaniraptora and Aves there seems to be stasis with Little or no morphological change. In short bird wings evolved prior to the emergence of Aves. Now this really isn't all that unexpected. Anyone who has been following the recent discoveries in bird evo area will know of the basal dromaeosaur Microraptor gui and it's asymmetrical feathers. And anyone comparing the forelimbs of Microraptor and Archaeopteryx can see how truly similar they are. Now interesting question is weather the flight evolved prior to the emergence of birds or weather the forelimbs of Eumaniraptors were co adapted for flight purposes. Microraptor seems to point to the direction of first hypothesis. We need more discoveries and the Jurassic lägerstatte of Dhaohugou holds lot's of promises, especially after the discovery of Epidexipteryx.

T. Alex Dececchi, Hans C. E. Larsson (2009). Patristic evolutionary rates suggest a punctuated pattern in forelimb evolution before and after the origin of birds Paleobiology, 35 (1), 1-12

PaleoArt #2

2009-02-05T06:15:00.000-08:00

Temnocyonine Amphicyonid from John Day beds, Temnocyon ferox.

You see! Mammals are taking over my brain.

Dinocrocuta: the real airhead

2009-02-05T05:48:00.000-08:00

The past few days I have been unusually mammal oriented.
Hyaenids, Canids, Amphicyonids, Ursids, Pinnipeds and Archaeocetes have all been on my reading list recently, and it doesn't help that they go and find such awesome new mammalian things as the new Protocetid whale Maiacetus inuus / (Blog coverage: Laelaps, The Loom

Well atleast some refreshing reptilian news came today in the newest issue of nature when the discovery of absolutely gigantic snake, Titanoboa, was announced. At 13 m in length and weighting 1,135 kg this snake was a whopper to say the least. (I guess the name Titanoboa was expected, but I would have advocated Crikeyboa instead.)
(Blog coverage: Not Exactly Rocket Science, Dracovenator)

However since both of these finds have been covered already by many excelent blogs in detail I find Little reason to repeat the same stuff again. Instead I'll cover something that seems to have passed most bloggers attention, and as title has foretold this will be about Dinocrocuta.

First little background. Although Dinocrocuta looks very much like a hyena and despite the fact that it shares many of the bone cracking adaptations that hyenas do, it is not one of them. Instead it belongs to Percrocutids, group of enigmatic carnivorans with high degree of convergence with true hyaenids, but differentiated from them based on dental and basicranial characters.

It was originally described from dental remains discovered from Chinese drugstore in 1903 by Schlosser. Schlosser Placed it as new species of Hyaena (Hyaena gigantea). It was not placed into genus Dinocrocuta till the discovery of first skull in 1988. At this time it came truly clear how distinctive this animal really was. It was big (Duh!), with condylobasal length about 32 cm (In comparison brown bear skull is somewhere around 35 cm). Skull has distinct stepped profile with deep zygomatic arches and massive post canine teeth.

It is quite clear to any observer that this skull is constructed for power and the clear convergence with true hyaenids indicates similar ecological niche.

To test exactly how well Dinocrocuta would do in a bone crunching task, the skull was run trough finite element analysis (Tseng, 2009).
Tested against modern grey wolf and spotted hyena, Dinocrocuta performed as expected, experiencing less stress on premolar 3 and 4 bite than either of it's rivals in this study.

The paper is really interesting, and future comparisons with other bonecracker , like derived Borophagine canids, will bring valuable information of the true convergence, and perhaps interesting divergent solutions to common problems that bonecracking lineages shared. However there was especially one figure in this study that peaked my interest.

(From (Tseng, 2009). Color emphasis mine)

Now what you are looking is saggital midskull section showing the internal structure of the skull.

(A. Spotted hyena B. Dinocrocuta C. Grey wolf)

Abreviation Fs indicates the frontal sinuses. It is well known that the posteriorly elongated
frontal sinuses of hyenas are expanded anteriorly and caudally extended (Joeckel, 1998).
This conditios is generally accepted as adaptation to greated loads and forces caused by premolar bonecracking (Ferretti, 2007).

This is obviously seen in both Spotted hyena and Dinocrocuta. But look at the size of the frontal sinus in Dinocrocuta! The cavity is larger than that reserved for the brains!

Indeed the brain seems to be half the size of that seen in both spotted hyena and and grey wolf.
I hope we are going to see somewhere in the future digital endocats study of Dinocrocuta.
Who knows, perhaps we learns something new of it's behaviour and phylogenetic position.

It seems that Zhijie Zheng is well on hes way making more interesting studies on fossil hyenid skulls and frankly I can't wait for the results.
By the way I wish to take this chance to advertice the blog, where he is one of the authors, called
Research and Expeditions. Go check that out...now.

References:

Joeckel RM. Unique Frontal Sinuses in Fossil and Living Hyaenidae (Mammalia, Carnivora): Description and Interpretation. Journal of Vertebrate Paleontology. 1998;18(3):627-639.

Ferretti MP. Evolution of bone-cracking adaptations in hyaenids (Mammalia, Carnivora). Swiss Journal of Geoscience. 2007;100(1):41-52.

TSENG ZJ. Cranial function in a late Miocene Dinocrocuta gigantea (Mammalia: Carnivora) revealed by comparative finite element analysis. Biological Journal of the Linnean Society. 2009;96:51-67.

Paul Sereno: What can fossils teach us?

2009-01-15T08:49:00.000-08:00

*11:08
That's one wicked croc skull.

Past issues of Acta Palaeontologica Polonica online!

2009-01-03T07:25:00.000-08:00

Now available from 1994-.

http://www.app.pan.pl/archives.html

Oh, and late happy new year 2009.

Speaking of Gobiderma...

2008-12-02T15:22:00.000-08:00

Heres a portrait of Gobiderma pulchrum I did last summer.

Out of print issues of PaleoBios available online

2008-12-02T13:51:00.000-08:00

Get your crispy old papers here.

New stuff at digimorph

2008-12-02T13:31:00.000-08:00

Digimorph is just one of those sites I just love to browse every now and then.
Nothing beats checking out skulls and drinking bloo....erhm....coffee.
Theres three new scans that certainly got my attention.

- Skull of fossil Monstersaur, Gobiderma pulchrum
- Skull of fossil iguanid, Temujinia ellisoni
- Braincase of Acrocanthosaurus atokensis

I found something cool today

2008-11-27T06:42:00.000-08:00

In the good old days roaming in dusty libraries in search of one paper was common practise. I must admit that there was a hint of excitement in trying to find that one precious paper, but one can hardly describe disappointment and frustration when one finally arrives to the right section, starts to browse trough the issues, and find out that the particular issue you were looking for is not where it's bloody supposed to be!

Frankly I don't miss those moments at all. Lucky for us we live at time where journals are making pdf copies of the papers, and monographs available. There are even whole websites like Biodiversity library, dedicated in preserving old papers and books in pdf form.

For student with limited budget these freely available sources are absolute goldmine, and certainly makes the literature search much faster and efficient.

Sometimes one can even stumble upon something interesting by shear luck while trying to find information about weirdest things.

Today, while I was trying to find papers about cloacal gill respiration of Fitzroy river turtle (Rheodytes leukops) I stumbled upon whole book about Australian herpetofauna freely available for anyone here.

Well illustrated with colour plates this seems like fantastic review of the amazing reptiles and amphibians of Australia. I was thrilled to find out that the same website hold second book on the same series. This time about Australian mammals!

Well, after moments of excitement and horrendous downloading fever, I continued my search for obscure turtle anatomy, and came across yet another book in pdf form, The anatomy of sea turtles.

Certainly good and well illustrated guide to anatomy of sea turtles.

I has bookls!

2008-07-10T02:55:00.001-07:00

Unexpected burst of inspiration caused catastrophic explosion of painting frenzy, so as you propably noticed this blog has been on sligth hiatus. But now couple of books have arrived to bring my mind back to paleo and animals. Magnificent mihirungs and Varanoid lizards of the world have just minits ago arrived and I'm exited.
You migth be hearing about varanids soon.

paleoart vol.1; Megalapteryx didinus- the highland moa

2008-06-25T10:10:00.000-07:00

Megalapteryx didinus was first described by Richard Owen in 1886. Like the other moas, it's known from multiple specimens, but what's even more awesome is that among those remains there are multiple naturally mummified specimens.
This portrait is based on mummified head and neck (MNZ S 27950) of Megalapteryx didinus.
I'm thinking of doing some Moa-Nalos next. Chelychelynechen is deliciously bizarre looking bird in desperate need of illustration.

Coming soon: giant lemurs of madagascar

double switch-blade of doom

2008-06-23T13:27:00.000-07:00

Anyone who has ever seen a rooster trotting on the farmyard, and has paid attention to their feet, knows that they have horn covered cone like spurs on their metatarsus. However perhaps less known is the fact that some birds bear similiar structures on their wings, specifically on their metacarpus.

I wasn't aware of such things existed, untill I read blog post by Darren Naish about recent litterature on phorusrhacids, where he mentions presence of carpal spurs in Anseriforms.

(How does phorusrhacids and anseriforms fit into one blog post? see full story here)

Carpal spurs are bony, horn covered projections originating usually from process of metacarpal 1, and in one case from radial carpal (Spurse-winged goose,Plectropterus gambensis). The shape and size varies from ”double switch-blade” of Screamers, to more often occurring single cone like spike, to blunt club like spur. They are present in both females and males of the species, and display slight sexual dimorphism, females having slightly larger spurs than males do.

Fig. 1 from (Rand,1954) Showing diverity of carpal spurs. A,Alectoris rufa; B,Haematopus ostralegus; C, Chauna chavaria; D, Plectropterus gambensis; E,Merganetta armata; F, Actophilornis africana;G 1,Jacana spinosa;G 2, Jacana spinosa;H, Belonopterus chilensis;I, Pezophaps solitaria

These structures are not widespread among birds. In fact well developed spurs are present in only two families, Anseriformes and Charadriiformes.

Within anseriformes Anhimidae(3 out of 3 taxa) and Anatidae (2 out of 144 taxa). Among Charadriiformes, Jacanidae (2 out of 7 taxa)
and Vannelinae (10 out of 25 taxa) are reported to have well developed spurs. (Rand,1954)

Although not carpal spurs per se, some birds have developed another ways to arm their wings.Those jacanas that lack spurs (Actophilornis africana,A. Albinucha,Metopidius indicus,Irediparra gallinacea) The radii are flattened and are heavy, much heavier than ulnae. Recently extinct fligthless solitaire,Pezophops solitaria, also evolved weaponry to their carpal area. In large specimens, presumably males, the distal end of the radius is expanded and proximal end of carpometacarpus forms blunt projection.

Spurs are used for some courtship purposes but more often for fight and defence.Powered by the massive flight muscles even spurless birds, like swans, can do quite bit of damage.
One can only imagine the damage that can be done with double blades of screamers.

I will never think of birds the same way again.

References:

Rand, A.L. 1954. On the spurs on birds' wings.
Wilson Bulletin: Vol. 66, No. 2.

Welcome!

2008-06-23T08:44:00.000-07:00

This is my attempt to make a foray into the vast and glorious world of blogging.

As those who are more familiar with the subject and may have pieced it together from the title and the quote below it, this blog will be heavily natural history oriented. Blog will mainly contain stuff what I find interesting in the natural world. What the interesting stuff exactly is, varies quite a bit. A while ago this blog would have been fully dinosaur oriented, but in these last 3 years I have opened my eyes to a much wider scope of interest. For that I can partly blame such excellent blogs like Tetrapodzoology, Laelaps, Catalogue of organisms, Blog of Mark Witton, World that we don't live in and many others.

Occasionally I might post some paleoart of mine, and discuss the subject of it, but mainly this blog is intended for my thoughts and ponderings about the natural history.

Soon to come: Double Switch-blade of doom