Some cool extinct animals images:
Saber-Toothed Cat Skull
Image by Travis S.
This is a closeup of a saber-toothed cat skull. The white strips show how the masseter muscles fit through the zygomatic arch and down to the mandible, making up the animal's cheek. On the side of the skull is a white plane showing the size of the muscle attachment. A similar display is shown for the nuchal muscles on the back of the skull of the cat with the atlas vertebra.
Also note the angle of the jaw which is larger than 90 degrees.
Effie the Woolly Mammoth
Image by Travis S.
In August of 1948, an unusual fossil was washed out of the much at a gold mine located on Fairbanks Creek, north of Fairbanks. It was the head, foreleg, and shoulder of a very young Pleistocene mammoth. It was nicknamed "Effie," after the Fairbanks Exploration (FE) branch of the United States Smelting, Refining, & Mining Company. A carbon 14 date from Effie's skin indicated that it died approximately 21,300 years ago.
The preservation of the skin, muscles, and connective tissue makes Effie the best preserved mammoth to be found in North America. These remains have furnished comparative material for the identification of blood stains on Alaskan stone artifacts that were used to kill and/or butcher mammoths. In addition, DNA analysis from Effie's tissue will help us understand to what extent the breeding lines of mammoth have diverged from a common ancestor.
Effie was in several parts when discovered. The mummy was the carefully embalmed, and the tears stitched together by University of Alaska scientists. The tearing was probably due to scavenging before burial. Effie would have been eaten almost entirely because the bones of such a young animal are soft and poorly ossified. The tip of the trunk was missing because it was eaten off. It is difficult to estimate the season of death because Effie lacked teeth, hair, and internal organs. Burial would have taken place during spring when snow was melting or possibly after a rare summer thunderstorm. It would have taken very little silt to bury this mammoth because it was so small. The skull and the rest of the skin were probably dragged away and not covered by silt, or the miners did not recognize the remains as they were washed away.
Age and the Circumstances of Death
Effie's size is the only clue to its age. An elephant in its first year averages about a meter at the shoulder, and based on this, Effie probably died during its first year. Elephants lose about half of their young during the first couple of years, and this probably held true for mammoths as well. Few elephant calves are actually killed by predators as the mother is too good a protector. However, since the female has to nurse the calf through its first winter, her condition is critical. Any female who produces less than optimum amounts and quality of milk is likely to lose her young. In this case, the young would be more likely to catch some disease, have an accident, or simply starve.
In conclusion, Effie was probably not killed by a predator, but died from malnutrition or an accident. The carcass would have been protected by the mother for a few days, then abandoned. Scavengers such as wolves, wolverines, or lions would have moved in, tearing through the tough skin to get to the other, more choice parts. Effie's death was not unusual. It was a natural and common part of the mammoth's life history. The death of such a young animal had little impact on the mammoth population as the mother soon came into estrous and had another young a couple of years later. The gestation period of elephants is about 22 months, a trait fairly constant in proboscideans. Mammoths probably had similar gestation periods.
You’re dirty, sweet and you’re my girl
Image by Mark Witton
Tell you what: of late I’ve done nothing but talk. Thanks to covering my PhD supervisor’s teaching load while he’s away on fieldwork for a month, I’ve been delivering 3 hour lectures, tutorials, assisting in practical classes, invigilating in-class tests and all sorts: I’ve been rambling on at students more than Led Zepplin II. The funny thing is, save for one seminar I’ve given on my own research, none of what I’ve said has been my own words. No, instead I’ve been regurgitating the songs of other researchers, putting what they’ve said into my own words and launching them at students. It’s a bit weird, really: I must’ve said thousands of words more than normal over the last week and yet, in a strange way, I feel like I haven’t really spoken to many people at all.
While I’ve been busy putting other people’s words into my mouth, a milestone in my career has drifted by virtually un-noticed. Yup, last week saw not only the publication of my first ever solo paper, but also my first ever contribution to the big list of animal species known to exist across time. Enter, stage left, Lacusovagus magnificens, a brand-spanking new pterosaur from Lower Cretaceous deposits of Brazil, described, illustrated and named entirely by yours truly. Given that a half-decent new taxon will be forever referenced and discussed in scientific literature until kingdom-come, this is, I guess, a reasonably big deal. Shame, therefore, that my reaction to its publication was something more akin to ‘oh, that’s nice’ than ‘hot-damn, I’ve been immortalised in the scientific literature’. Even as I write this, I can’t shake the feeling that I really have more pressing concerns to address like putting a lecture together or reading through some proofs but, dammit, it’s been ages since I wrote anything other than some hastily worded E-mails, so write I will: the words of other people will have to wait for a few minutes longer.
So, what is this Lacusovagus beastie all about, then? Well, the holotype specimen (that is, the specimen to which the name Lacusovagus magnificens is attached to) was sourced from the Crato Formation of Brazil, the age of which isn’t entirely clear. Based on fossil spores and pollen, the Crato Formation seems to have a ballpark age of about 110 million years old, dumping it towards the top of the Lower Cretaceous. This stretch of time records one of the richest, most diverse pterosaur faunas we know of: between the famous Jehol Group of China (you know, the place that's blossoming with all those fuzzy dinosaurs you see splashed across the news every-so-often), the Crato Formation, the neighbouring Santana Formation and a few other sites, we know of at least ten major groups of pterosaurs around at this time, and God-knows how many different species. So, Lacusovagus doesn’t exactly rewrite our knowledge of pterosaur temporal distribution, then: in this respect, it simply adds another name to the already-long list of pterosaurs known from this time.
What is a bit more exciting, though, is what Lacusovagus is. It took a little while to verify exactly what Lacusovagus was because of the, frankly rather crappy, nature of the holotype. Affectionately known to its friends as SMNK PAL 4325, the only known specimen of Lacusovagus is simply a fragmentary rostrum – essentially the front end of the upper beak and elements of the bars making up most of the skull length (to be all technical, we’ve got the complete pre-nasoantorbital fenestral rostrum, most of the right maxillary bar, some of the left maxillary bar and a short stretch of the posterodorsal extension of the premaxillae). Unusually for a Crato pterosaur, SMNK PAL 4325 is preserved with the roof of its mouth flat in the sediment, making it damned difficult to see even the most basic features of it - like the presence of absence of teeth. Adding to this problem was the fact that the chaps who collected the specimen decided that, because the limestone slab housing the skull was quite thin and delicate, they would secure another slab to the underside. In theory, this is an excellent idea because, hey, no-one wants their sexy new pterosaur skulls to split in two, but they used car body filler to cement the slabs together. We removed a section of the bottom limestone slab pretty easily, but the infernal car filler was a real cow to get through. In fact, only a tiny portion was removed before the juxtaposition of bloody inert car filler and delicate fossil became too much of a liability for preparation to continue. What you can see of the underside of the jaw shows no sign of teeth, and we later CT scanned the specimen to find a similar result. Thus, whatever Lacusovagus was, it didn’t have any teeth.
Thankfully, other aspects of Lacusovagus ‘s skull weren’t so difficult to see. Although pretty fragmentary, we’ve got enough of the skull preserved to show that the skull was quite long – at least 655 mm and probably well-over 700 mm when complete – but, based on doubling the width of the widest part of the skull, it’s also unusually wide. This is something you don’t get too often in pterosaurs: their skulls are typically quite slender (though no-where near as paper-thin as suggested by some workers), with only aberrant, derived things like istiodactylids and tapejarids having proportionally wide skulls. Lacusovagus stands out with weird skull proportions, combining a long snout with a relatively wide skull. In fact, only one toothless pterosaur, Tapejara, has a wider skull for its length than Lacusovagus.
And that’s not the only weird thing about Lacusovagus. For a long-jawed pterosaur, its rostrum – the bit of the beak in front of its nasal opening (although, of course, pterodactyloid pterosaurs have fused nasals and antorbital fenestrae – but you knew that already, didn’t you?) is pretty short. Given that the jaw is not entirely complete (but I figure most of it is there), the ratio of jaw length to rostral length will be even shorter in a complete specimen. The unusually wide skull is also reflected in the rostrum, which is pretty chunky along much of its length. However, unlike an awful lot of edentulous pterosaurs from the Lower Cretaceous, there’s not a hint of a headcrest anywhere along the skull. Given that the specimen is osteologically mature, it’s unlikely that it’s crestlessness (um... that may not be a real word) can be put down SMNK PAL 4325 being an immature individual still awaiting the crest development, shoegaze music and moodiness that would arrive with puberty.
So, are these features enough to give an idea of what SMNK PAL 4325 actually is? Well, it looks like Lacusovagus can be quite reliably shoved inside the pterosaur group Azhdarchoidea, the social club that also features thalassodromids, tapejarids and azhdarchids. However, it can’t be placed in any of these ‘classic’ azhdarchoid groups: no, Lacusovagus finds its closest chums in a relatively new pterosaur group, Chaoyangopteridae. These chaps – like Lacusovagus - have long, edentulous jaws with shallow, crestless rostra, big nasoantorbital fenestra and - a bit like azhdarchids - long neck vertebrae. Now, when I submitted the Lacusovagus manuscript to Palaeontology I hadn’t verified the chaoyangopterid affinities of SMNK PAL 4325 with any kind of cladistic analysis, but I managed to work one into my PhD thesis: in all recovered trees, Lacusovagus hangs out with the likes of Jidapterus, Eoazhdarcho, Eopteranodon, Chaoyangopterus and Shenzhoupterus - certified chaoyangopterids - to the exclusion of all other azhdarchoids. Interestingly, I found Chaoyangopteryidae to form a little clade with Azhdarchidae, suggesting that long necks only evolved once within Azhdarchoidea. Neat.
Now, if pterosaur palaeobiogeography floats your boat, finding a chaoyangopterid in Brazil is extremely cool. Chaoyangopterids, y’see, have thus far only been found in the Jehol Group of China. Lacusovagus, therefore, provides the first record of these guys outside of Asia and suggests that this otherwise poorly-known group were far more widespread than previously realised. It also heightens the faunal similarity between these two localities, suggesting that we should expect pretty similar pterosaur diversity between China and Brazil. All in all, it goes to show that we’ve still got a hell of a lot to learn about pterosaur diversity and biogeography and emphasises just how reliant we are on fossil lagerstätte – sites of exceptional fossil preservation like Crato and Jehol – to tell us what pterosaurs were up to at any given time in their evolutionary history.
Anyway, that’s about all I’ve got time to tell you about Lacusovagus for now. Only two more things are worthy of mention: with an estimated wingspan of 4 – 5 m, Lacusovagus is the biggest chaoyangopterid yet known and the biggest pterosaur from the Crato Formation (estimated mass of 20 kg, wingspan-mass regression fans). I mention this because, like all palaeontologists, my main concern is that any animal with my name attached will kick the asses of its contemporaries and closely-related animals. Finally, a quick word about the name: I really wanted to avoid another terribly dull place-name-opterus or something like that with my first scientific moniker. Hence, Lacusovagus magnificens translates from Latin to ‘magnificent lake wanderer’, a reference to the fact that the specimen comes from the Crato water body and was of some magnitude in size. This name, for some reason, really makes me want to listen to The Beatles’ Magical Mystery Tour album. Hmm: probably just me, that one.
Oh, and as usual, there's been no mention of the picture at the top of the text: what you've got there is the first ever restoration of Lacusovagus, suitably wandering around the margins of the Crato lagoon. Which is nice. Anywho, thanks to all those who helped out on the paper and with figuring out the specimen. Much appreciated.
UPDATE (4/12/08): Well, bugger me: this whole Lacusovagus thing has gone crazy in the last few days. It's been in the national papers, national radio, is all over the internet like a cheap suit and may even end up on the TV. It's funny to think that I only contacted our press office with the idea that someone - maybe, one, two bloggers, tops, would find Lacusovagus interesting: now it's a bona fide international megaevent. Crazy stuff. The best bit, is though, that the BBC have used my scale graphic for their picture caption of the week competition. So far, I've been likened to John Lennon, David Bowie, Rod Hull, Noddy Holder and at least two people can't figure out what sex I am. Superb (the BBC stuff, that is: not gender confusion. Not that there's anything wrong with that, you understand - I'll freely admit to dressing in a rather androgynous fashion on occasion and am perhaps favourably compared to women somewhat more often than I should be comfortable with. And I do moan about men a lot, so, hey, gender confusion is savvy with me. Um, where are we going with this? This is a sort of corner I've written myself into here: best trail off...)