Thylacoleo carnifex, ancient Australia’s marsupial lion

31 08 2007

My home state of New Jersey is the epitome of suburban sprawl, McMansions and cul de sacs being about as common as the White-Tailed Deer that take advantage of the grass and brush on the side of the Garden State Parkway year round. There is seemingly no place you can go in the state where the rumble and roar of traffic cannot be heard, although the sprawling network of impervious surface does allow for easy travel to almost anywhere in the “Garden State.” On these roads, usually on warm summer nights, you’re likely to see what appears to be a large white rat shuffling across the lanes. While there are no hackneyed jokes that I know of about the Virginia Opossum crossing the road (“To eat your garbage” would be the most realistic answer), the critters turn up as roadkill quite often, not a very dignified end for the only marsupial mammal to live north of the Rio Grande in North America. While the scruffy Virginia Opossum represents the whole of marsupial mammals in the U.S., it has many close relatives throughout South America (Order Didelphimorphia), and is a bit more distantly related (but still close) to the Australian “possums” (Suborder Phalangeriformes), the marsupial forms of “the island continent” being perhaps the most familiar and oddly charismatic of any members of the Infraclass Marsupialia.

Kangaroo
A Red Kangaroo (Macropus rufus) at the Philadelphia Zoo (taken in February, 2007). The Red Kangaroo is probably the world’s most recognizable living marsupial mammal.

Much like any group of living mammals, however, the fossil record of marsupial mammals is full of bizarre forms that have left no living descendants. We should not regard such lines of extinct fauna as somehow inferior or flawed, however. As famed paleontologist Stephen Jay Gould once wrote in his book Wonderful Life;

First, in an error that I call “life’s little joke”, we are virtually compelled to the stunning mistake of citing unsuccessful lineages as classic “textbook cases” of “evolution.” We do this because we try to extract a single line of advance from the true topology of copious branching. In this misguided effort, we are inevitably drawn to bushes so near the brink of total annihilation that they retain only one surviving twig. We then view this twig as the acme of upward achievement, rather than the probable last gasp of richer ancestry.

I can scarcely think of a better example of this notion of the spectacular diversity of past life than the extinct marsupial Australian Megafauna, and the carnivorous Thylacoleo carnifex would remind any fossilist that just because an animal is extinct, such status does not imply that it was not a terror in its heyday. Deemed the “Marsupial Lion” Thylacoleo carnifex developed many of the predatory adaptations we seen in living big cats (hence the “leo”, meaning “lion”, in the genus name), and despite the superficially rodent-like appearance of it’s front teeth, it was certainly a powerful predator.

In order to understand why Thylacoleo was such a formidably hunter we first need to understand something about living Carnivora (civets, otters, cats, dogs, bears, etc.) and the way their teeth were arranged. While their have been many large carnivorous mammals since in the past 65 million years, carnivores are set apart by their carnissal, or “scissor”, teeth. If we look at the massive skull of the predatory mesonychid Andrewsarchus of the Eocene, for example, the front teeth appear useful for piercing but the teeth further back in the jaw a large and a bit blunted. While useful in tearing flesh from bone and crushing, they were not especially well-adapted to cutting slicing flesh and such creatures probably ate a fair amount of bone (and possibly had problems with bone splinters in their gastrointestinal tracts) as well.

Andrewsarchus
The only known skull of Andrewsarchus, on display at the American Museum of Natural History in New York City. Note the large, blunted teeth towards the back of the jaw.

The likely ancestors of today’s extant carnivores had their start long before Andrewsarchus was roaming what is present-day Asia. Miacids were weasel-like mammals and are known from the Paleocene and Eocene epochs, and are the first mammal group known to have teeth called “carnissals.” These are the teeth that group all living carnivores together, robust and pointed teeth that seem to be essential to consuming flesh. Another group of mammals, the creodonts (the first of which were discovered by E.D. Cope), also possessed carnissal teeth, but their line died out about 8 million years before the present. Still, the success of the carnivorous mammals seemed to depend on the specialization of the some of the premolar and molar teeth into a sharp, cutting edge, commiting many of the group to a strictly carnivorous lifestyle. Cats are the most specialized today, as they have lost some teeth in the front of their jaw in order to allow their dagger-like canines to have the maximum effectiveness and they no longer have flattened molars at the back of their jaw like canids (dogs) have, allowing those animals a little bit more of a diverse diet in tough times. Indeed, overspecialization in a predatory niche, called “hypercarnivory,” can often put a species at risk if they cannot effectively process other food sources if prey stocks dwindle (such a hypothesis has been put forward about the recent “bone-crunching wolf” discovered in Alaska).

Thylacoleo
A replica of the skull of Thylacoleo, on display at the American Museum of Natural History.

Thylacoleo, however, was an entirely different branch of the mammalian tree, but it seems that its skull and jaws were adapted to similar ends (although arguably were more extreme in their modifications). As easily seen from the skull of Thylacoleo, this marsupial predator was adapted to have it’s own fearsome shearing teeth. The premolars essentially became laterally-compressed blades, more high-ridged and pointed at the front, yet still sharp all the way down their length. These teeth in the upper and lower jaw even helped to sharpen each other as they slid past, allowed the predator to retain a sharp edge. Flattened teeth that might be useful for grinding or processing other foods are entirely absent behind the premolars, showing the Thylacoleo was a specialist of the highest order, having much more scissor-like teeth than the placental carnivores on other continents. Such a gape would have been absolutely fearsome, as exemplified by this recent reconstruction by Jeanette Muirhead;

Thylacoleo
Thylacoleo carnifex, used with permission of artist Jeanette Muirhead.

What is even more surprising than the blade-like teeth of Thylacoleo, however, is how strong its jaws were for a creature of its size. A recent study by Wroe, McHenry, and Thomason found that Thylacoleo, a predator that was less than four-feet long and probably weighed only 220 pounds, had the a bite force equivalent to a modern lion twice its size. The unusual dental arrangement of its jaw might have mitigated this somewhat and technical trials still have to be carried out, but if what the researchers found holds then Thylacoleo could probably have preyed upon most animals living in its range up to sub-adult size on its own, perhaps being the fiercest mammalian predator ever known.

How did Thylacoleo attain such high bite forces? The answer might have to do with the brain and skull differences between marsupials and placental mammals. Many carnivores have relatively large brains in comparison with marsupials, lessening the amount of bone they can devote to massive muscle attachments to enhance bite force. Thylacoleo, by contrast, seems to have had stronger muscle attachments and a smaller brain, and it’s skull superficially resembles that of a big cat. While canids often have elongated skulls, cats have foreshortened ones, and oddly enough Wrote and his colleagues seem to have found that carnivorous mammals that are known to be bone crunchers (primarily dogs or dog-like carnivores) appeared to have overall weaker bite forces than those that did not have the same osteophagous tendencies. This may have to do with the actual killing of prey, big cats and similarly-designed predators depending on strong bite forces in order to choke their prey to death or tear out a large chunk of the prey’s neck with a jugular bite. There are exceptions to this, the bite of saber-toothed cats often being calculated as relatively weak, but overall it seems that a shorter skull with a deep mouth is better of achieving high bite forces than a longer and narrower one. Hence, Thylacoleo actually is not a bad name for the “pouched lion”; it seems to share a large amount of convergences with its modern-day namesake, although it may have been less bright (and less sociable) with a more powerful bite.

Thylacoleo
Ventral view of the skull of Thylacoleo. From E.D. Cope’s “The Tertiary Marsupialia” in The American Naturalist, Vol. 18, No. 7. (Jul., 1884), pp. 686-697.

The predatory affinities of this animal did not always seem so obvious, however. Paleontologist E.D. Cope, in a paper entitled “The Tertiary Marsupiala,” recaps some of the controversy about the feeding habits of Thylacoleo that formed in the late 1800’s;

The discussion between Professor Owen on the one side, and Messrs. Falconer, Krefft and Flower on the other, as to the nature of the food of Thylacoleo, is known to paleontologists. From the form of the teeth alone, Professor Owen inferred the carnivorous nature of the food of this genus, while his opponents inferred a herbivorous diet from the resemblance between the dentition and that of the herbivorous Hypsiprymnus. I have pointed out that the comparison of Thylacoleo with Hypsiprirnnus is weakened by two considerations :

First, the cutting teeth in the two genera are not homologous ; second, the grinding series of molars, complete in Hypsiprymnus, is almost wanting in Thylacoleo. It evidently does not follow that because Hypsiprymnus is herbivorous Thylacoleo is so also. Professor Flower refers to the reduction of the molars in Thylacoleo as slightly complicating the problem, and concludes that the food of that animal may have been fruit or juicy roots, or even meat. It is difficult to imagine what kind of vegetable food could have been appropriated by such a dentition as that of Ptilodus and Thylacoleo. The sharp, thin, serrate or smooth edges are adapted for making cuts and dividing food into pieces. That these pieces were swallowed whole is indicated by the small size and weak structure of the molar teeth, which are not adapted for crushing or grinding anything but very small and soft bodies. It is not necessary to suppose that the dentition was used on the same kind of food in the large and the small species… In Thylacoleo carnifex it might have been larger eggs, as those of the crocodiles, or even the weaker living animals. The objection to the supposition that the food consisted of vegetables, is found in the necessity of swallowing the pieces without mastication. In case it should have been of a vegetable character the peculiar premolar teeth would cut off pieces of fruits and other soft parts as suggested by Professor Flower, but that these genera could have been herbivorous in the manner of the existing kangaroos, with their full series of molars in both jaws, is clearly an inadmissible supposition.

I have to agree with Cope; it is hard to imagine what sort of vegetable matter Thylacoleo would be eating with its specialized dentition. It would have been able to chop plants, surely, but whatever food was not inside the mouth would fall into the ground, that inside the mouth would have to be swallowed whole. This would results in Thylacoleo chewing much more low-quality plant food than other animals with teeth adapted to herbivory, and I doubt that Thylacoleo had a caecum or a habit of swalling smooth stones to aid in the digestion of the hypothetical greenery. Even in 1969, however, there seemed to be some doubt as to whether Thylacoleo was a herbivore, an omniovore, a carnivore, or a hypercarnivore. Leigh Van Valen, in the paper “Evolution of Dental Growth and Adaptation in Mammalian Carnivores”, wrote;

The jaw musculature of Thylacoleo was generally similar to but more powerful than that of Trichosurus, but whether all this increase was an adaptation to greater size is unknown. The question of the diet of Thylacoleo is unresolved. If Thylacoleo was carnivorous, it was in several respects a relatively inefficient carnivore. However, large carnivores were rare in Australia, and the condition of Thylacoleo is what would be expected if a Trichosurus-like phalanger became carnivorous. But the herbivorous diet advocated especially by Flower, Krefft, Lydekker, Charles Anderson, and Gregory remains a real possibility. A decision on this matter will probably not be possible until there is adequate knowledge of the appendicular skeleton.

The initial descriptions of Thylacoleo by Richard Owen were more certain of the carnivorous habits of the marsupial, however. One December 16, 1858, Owen’s paper “On the Fossil Mammals of Australia. Part I. Description of a Mutilated Skull of a Large Marsupial Carnivore (Thylacoleo carnifex, Owen), from a Calcareous Conglomerate Stratum, Eighty Miles S. W. of Melbourne, Victoria” was read before the Royal Society. It states;

The evidence of a large carnivorous marsupial, from pliocene formations in Australia, reached me not many years after my determination of the still larger herbivorous marsupial, Diprotodon australis, which first suggested the idea of the coexistence. The evidence was received in the year 1846…

Thylacoleo
The fragmentary skull of Thylacoleo from Owen’s paper “On the Fossil Mammals of Australia. Part I. …”

The initial fragmented skull of Thylacoleo carnifex (Owen), pictured above, was obtained and sent to the great naturalist by Dr. Hobson of Melbourne. Upon receiving the fossils, it seems that Owen almost immediately recognized the convergences in the skull with modern carnivores, the extant lion (Panthera leo) being his foil for the characters in the new skull. Owen describes the deterministic state and characters of the skull as follows;

The ‘skull’ consisted of the cranial part, similar in size and in the development of the temporal ridges and fossae to that of a Lion. The ‘incisor’ was a large tooth with a trenchant or incisive crown, implanted, with a small tubercular tooth, in a portion of the right superior maxillary bone, including part of the orbit and lacrymal bone. The latter specimen gave decisive confirmation of the carnivorous character of the fossil, the ‘incisor’ tooth answering in shape and function to the great sectorial or ‘carnassial’ and the tubercular tooth to the small tubercular molar of the Lion; being situated, as in that animal, on the inner side of the back part of the sectorial tooth.

Indeed, the bladelike teeth alone were enough to convince Owen of the ferocious nature such an animal must have possessed, writing;

In existing carnivorous mammals the ferocity of the species is in the ratio of the ‘carnassiality’ of the sectorial molar, i. e, of the predominance of the ‘blade’ over the ‘tubercle;’ and this ratio is shown more particularly in the upper sectorial, in which, as the tubercular part enlarges, the species becomes more of a mixed feeder, and is less devoted to the destruction of living prey. From the size and form of the carnassials of Thylacoleo, especially of the upper one, we may infer that it was one of the fellest and most destructive of predatory beasts.

Thylacoleo
A second, more complete skull of Thylacoleo carnifex, from Owen’s paper “On the Fossil Mammals of Australia. Part II. Description of an Almost Entire Skull of the Thylacoleo carnifex, Owen, from a Freshwater Deposit, Darling Downs, Queensland”

Owen’s assertions did not go unchallenged, however. In a later 1886 paper “Additional Evidence of the Affinities of the Extinct Marsupial Quadruped Thylacoleo carnifex (OWEN),” the anatomist includes a quite humorous remark in response to one of his critics. As noted before, some scientists believed that Thylacoleo was essentially a living Cuisinart specializing in cutting up fruit, no more terrifying than some of the arboreal relatives of the Virginia Opossum noted above. Owen, in classic style, writes;

These eminent authors received the support, in reference to objections to my conclusions, of the (then) Curator of the Australian Museum, Sydney, Mr. GERARD KREFFT, who, in his contribution to the ‘Annals and Magazine of Natural History,’ series 3, vol. 18, 1866, p. 148, records his opinion that “the famous marsupial Lion was not much more carnivorous than the Phalangers of the present time.”

The species of carnivorous Phalanger is not named. No evidence of such by fossil specimens has reached me, nor have I found such exceptional habit of an existing species of Phalangista elsewhere noted.

Thylacoleo
Lower jaw (outside view) of Thylacoleo carnifex, as seen in Plate I of Owen’s “Additional Evidence of the Affinities of the Extinct Marsupial Quadruped Thylacoleo carnifex (OWEN)”

Indeed, armed with a more complete lower jaw of the animal, Owen even further extrapolated its carnivorous habits, postulating that it had been the “check” on the large herbivores known from the same period in Australia. All the large forms, in Owen’s view, ceased to exist when “bimanous” forms came to the continent, either eliminating Thylacoleo or putting it out of a job through competition, although the wholesale slaughter of Australia’s megafauna by the people who would become the Aborigines is not an open and shut case. Even beyond the skull, Owen was provided with a claw complete with retractable teeth, now known to occupy the “thumb” position of this carnivore. Some have speculated that its size, ferocity, and retractable claw allowed it to climb trees like a leopard, although others have doubted this an account of how robust Thylacoleo probably was (being twice the weight of modern leopards), which 1) would have made it difficult to climb trees, and 2) would have allowed it to chase off most of the competing predators/scavengers of it’s day. I doubt that there were many creatures that would have crossed the path of Thylacoleo and survived if the “pouched lion” was hungry or territorial.

Despite it’s fearsome reputation, Thylacoleo seems to have disappeared from the land “down under” around 40,000 years ago, probably the very last of its lineage. Indeed, while I have primarily focused on Owen’s T. carnifex here, there were many other earlier species and related genera, each showing different aspects of the skull and form. Why these bizarre creatures, once so prominently disputed, have disappeared from the public understanding of paleontology I cannot say, but it is probably to the relief of living kangaroos and other Australian fauna that they are long gone.

Thylacoleo
Partial skull elements, most notably the incisors, from Owen’s paper “On the Fossil Mammals of Australia. Part IV. Dentition and Mandible of Thylacoleo carnifex, with Remarks on the Arguments for Its Herbivority”





Icon of Delusion: Jonathan Wells

31 08 2007

If ever there were an unsavory, real-life creationist character that should be cryptically referred to as “You Know Who” as in the Harry Potter series, it would have to be Jonathan Wells. While I have not actually tested this as yet, the very mention of his name seems to make my blood pressure rise, and perhaps his goal is to be so annoying and deceitful that evolutionary scientists all die of stress-induced heart attacks because they can not even stand the mention of his name. If this is indeed the plan, then Wells has certainly taken another step towards its fruition. On the dubiously titled “Evolution News & Views” blog run by the Disco. Institute, Wells has issued a rather hateful screed about the terms “Darwinist” and “Darwinian.”

Starting out with a rather hateful attack on the quality of The Seattle Weekly, stating that “as [a source] of news [it's] probably about as reliable as Minju Choson, the official organ of the Democratic People’s Republic of [North] Korea. But homeless people make good use of [it],” Wells quotes a recent article in the paper in which Eugenie Scott of the NCSE as saying “a real follower of modern science would never call himself a ‘Darwinist’,” because “evolutionary biology has advanced way beyond Darwin’s 19th-century tracts.” This is rather strange, especially the quotation marks that Wells decided to “helpfully” insert as they do not appear in the original article. The original sentence reads as follows;

Scott isn’t buying it, not least because she says evolutionary biology has advanced way beyond Darwin’s 19th-century tracts, so that a real follower of modern science would never call himself a “Darwinist.”

Sounds more like the reporter, Nina Shapiro, tried to condense Scott’s argument down into a shorter sentence and was not quoting Scott directly, so once again Wells has shown us that he is either being deceitful or ignorant of how to properly use the copy-paste function on a computer. Still, he uses his doctored quote as a set-up to try and muddy the waters with cherrypicked examples from historical science, and Wells misses the entire point of the now outdated term “Darwinist.” Wells writes;

The reason that “Darwinism” and “Darwinian” – even “Darwinist” – are used by modern evolutionary biologists is that they are more precise than “evolution” and “evolutionist.” The latter have many meanings, most of them uncontroversial. For example, “evolution” can refer simply to change over time, something no sane person would deny. Or it can refer to minor changes within existing species, which breeders have known about for centuries.

Actually, the reason why “Darwinist” was the most popular term in years past is because Darwin’s mechanism of natural selection (and later sexual selection) proved to be the correct one. Prior to Darwin and even during his time “transmutation” of species was a hot topic, and there were various schools of thought as to how creatures evolved. Thus a more exact term for the school of evolutionary thought Darwin founded, “Darwinism,” was necessary to distinguish it from the competing hypotheses of Lamarck, Agassiz, the thoughts put forth in the popular book Vestiges of the Natural History of Creation by Robert Chambers, and the later criticisms of Darwin put forth by the likes of St. George Mivart. In fact, especially in America, evolution by natural selection was not immediately and fully embraced, the famed scientist Louis Agassiz being a critical of Darwin so vociferous that even Wells would have been likely to get his admiration. Even the noted paleontologist E.D. Cope ascribed to Neo-Lamarckian ideas of evolution, a evolutionary framework that has been long known to be insufficient.

But if Darwin was right, why would Eugenie Scott say his “tracts are outdated”? Well, Darwin was right in terms of his big ideas of natural & sexual selection (as well as many other points), but he did get some things wrong. Heredity was vastly unknown during his time, and even Darwin threw in a pinch of Lamarckism into his writings. In the 2nd edition of The Descent of Man, Darwin wrote the following in the preface;

I may take this opportunity of remarking that my critics frequently assume that I attribute all changes of corporeal structure and mental power exclusively to the natural selection of such variations as are often called spontaneous; whereas, even in the first edition of the ‘Origin of Species,’ I distinctly stated that great weight must be attributed to the inherited effects of use and disuse, with respect both to the body and mind. I also attributed some amount of modification to the direct and prolonged action of changed conditions of life. Some allowance, too, must be made for occasional reversions of structure; nor must we forget what I have called “correlated” growth, meaning, thereby, that various parts of the organization are in some unknown manner so connected, that when one part varies, so do others; and if variations in the one are accumulated by selection, other parts will be modified. Again, it has been said by several critics, that when I found that many details of structure in man could not be explained through natural selection, I invented sexual selection; I gave, however, a tolerably clear sketch of this principle in the first edition of the ‘Origin of Species,’ and I there stated that it was applicable to man.

And so I still cringe when I heard scientists refer to themselves as “Darwinists” (or even worse, “orthodox Darwinists,” as I once heard Ken Miller opine). The term is no longer necessary or even accurate because in scientific understanding Darwin’s big ideas won the day ages ago while some of his subjects he did not fully understand have become better known, the science we now have being based on Darwin but not adhering only to the thoughts within his published works. If we’re going to start tagging schools of thoughts with names, we could very well have “Gouldists,” “Dawkinsists,” “Simpsonists,” “Mayrists,” “Morganists,” “Copeists,” “Agassizists,” etc. etc. etc. The distinction that the term “Darwinist” used to have is now largely lost because of our greater understanding, time proving Darwin to be the victor in the battle that took place in evolutionary through between the late 19th and early 20th centuries, but I know of no scientists who holds On the Origin of Species by Natural Selection who holds the great work to be a holy book that may not be added to or contradicted in any fashion whatsoever. Just like paleontology requires a historical understanding and a long-view of the subject at hand, so does the topic of the evolution of how we think about biological evolution.

After some more jabs at Scott and confusion of the origins of the words he’s talking about, Wells concludes;

So rather than learn Scott’s word games, biology students should begin by learning to distinguish “evolution” from “Darwinism” and “evolutionist” from “Darwinist.” Or “Darwinian” – it’s one and the same.

I assume that he’s not suggesting that school boards should hire Neo-Lamarckian staff to “Teach the Controversy!” about evolution. I think a biology class would largely benefit from understanding the historical aspect of the evolution idea, starting with the Ionians like Thales and Anaximander and working through Darwin and the Modern Synthesis to today. That way it can be clearly seen that there indeed was a time when evolution did not necessarily mean “natural selection, common descent, etc.” in the minds of some notable scientists, and how eventually their ideas (often influenced by their adherence to religious doctrine) came crumbling down. “Teach the Controversy!” seems like it could have just as well been the battle cry of Louis Agassiz or St. George Mivart as that of current ID thinkers, but apparently they cannot be bothered to go back and try and uncover the history of the evolution idea.

To put it concisely, Darwin was a highly intelligent man who uncovered the beginnings of one of nature’s greatest mysteries, but we would be fools to think that he was somehow all-knowing or that no data would later be found that would clarify or possibly refute his ideas. Nearly 150 years after On the Origin of Species by Natural Selection was published, however, natural selection working on variations in organisms is still a major mechanism of evolution, exemplified by Stephen J. Gould in his coral-branch analogy in The Structure of Evolutionary Theory. Can we expect any scientist never to make a mistake or never have their ideas overturned? For every important idea that has been put forth by great minds, how many ideas ended up being stillborn or eventually refuted? Are we to remember scientists for their failures only, disregarding their successes? To do so would mark us imbeciles, and we would pay a heavy price for judging those who strove to bring enlightenment to the work by sharing their ideas. Darwin was one of those great minds, and even though “the long argument” will likely continue, I see no reason why we should exhume the corpses of long-dead competing hypotheses of evolution when Charles so eloquently put laid to rest.





Amalgamated Friday Notes

31 08 2007

So here we are, the last day of August. This morning when I stepped outside to drop the mail into the corner box, the orange light struck the trees and small flocks of chickadees pecking at the sidewalk just right, a few crickets continuing on the evening chorus of chirps. No one was around despite the relatively late hour and I had the sidewalk to myself, reminiscing about such morning in Florida, a place I am much more fond of. Still, it was not a bad moment to part with my summer, and I’ll be counting the days until it comes again.

Indeed, this is the last weekend before school starts, and I’m pretty tied up for most of the weekend. I hope to get some writing done, but I have no idea how much. On the book front, I’ve been trying to get through as many books as possible before school starts. The other night I read T.H. Huxley’s Man’s Place in Nature and it was an utter delight. Some parts were a bit dry, but when let loose from measuring skulls, feet, or hands to pontificate upon the subject of the book named in the title, Huxley is at his best. I am sorry I had not read it sooner.

At the moment I’m reading The Bonehunter’s Revenge aloud to my wife, and it is one of the most enjoyable popular science/history books I’ve come across as of late. The author, Wallace, gets some of his history muddled in only giving it a brief mention (he fumbles a bit in his discussion of Cuvier and Lamarck and at one point calls a titanothere a titanosaur), but overall the prose flows well and tells and exciting story, tying it all together with the famous feud between Cope and Marsh in the Herald. If you’re tired of simply hearing that Cope and Marsh had long-standing ill-will towards each other and want to know why, I highly endorse picking up a copy of this book (and if you like card games, check out Bone Wars, too!). Being that I have to wait until the evening to read Wallace’s book aloud to my wife, I spent most of yesterday evening reading the companion volume to the BBC series The Velvet Claw. I never got to see the series, nor am I likely to as it seems to never have come out on DVD, but the book is definitely a well-illustrated overview of living and extinct carnivorous mammals. It is a bit dated in some of it’s paleontology(Pakicetus was still thought of as a half-seal at this time), and it can be a bit dry at times, but it has been a very useful book.

In fact, The Velvet Claw and Jeremy’s recent post about the scent-marking habits of Binturongs has inspired me to write about something that I have not yet seen covered in full in the blogosphere; genital mimicry in cat-line carnivorans. Spotted Hyena are the most famous example, but they are not alone in appearing androgynous; Binturongs, Fossas, and some other living carnivores on the cat-side branch of the evolutionary tree also express genital mimicry (the parts of the females looking like those of the males), and upon learning this I definitely became more interested in just how widespread such a condition is among civets and their relatives. I’ll have to do a bit of research before I get churn that one out (I’m now even more thankful that I picked up Walker’s Mammals of the World), but hopefully I’ll have it done soon.

Like I mentioned earlier, this weekend sees me pretty booked up, but next weekend I hope to visit the Philadelphia Zoo (I’ve been waiting to go all summer, and other plans continually got in the way), so expect plenty of pictures of the various critters there. Hopefully I’ll snag some shots of the tiger cubs born this past spring, but if I’m going to do that I’m going to have to get there a bit early.

I should probably get back to work on my post about a certain killer marsupial that was roaming Australia until the end of the Pleistocene, though, and I hope everyone returning to school gets to enjoy the long weekend before the semester sets in full-force.

Update: I nearly forgot a few things I meant to add. First, my wife brought home a 6-bottle pack of Woodchuck Draft Cider last night and it was really good. I’m told that Woodpecker Cider is better, but I won’t complain about the Woodchuck brand, especially since it’s got the scientific name on the bottle.

Second, my wife is interested in the Carnivora as much as I am, and she definitely wanted to read The Velvet Claw. Being a bit tired, she picked up the book to flip through it, and when she had stopped I asked for it so I could start it. She held it close and got a distrustful look in her eye and said “Mine.” I replied “But you didn’t even know the book existed until I bought it.” She shot back “Just because I didn’t know about it doesn’t mean it’s not mine.” She soon relented and will start on the book soon herself.

Lastly, my wife related an anecdote to me of her trip to the liquor store to get the aforementioned Marmot Woodchuck Cider. Last night was the 1st football game of the season for Rutgers, so hordes of freshmen swamped the streets and stalls of local purveyors of alcohol. In one such establishment, a young man said to my wife (as related by her to me) “Hey, I’m totally, like, having a party later and you should, like, totally come.” My wife, clever as I know her to be, replied “Oh yeah? I’m having a party too.” The young man, somewhat expectantly said “Oh yeah? Really?”, my wife swiftly interfecting “Yeah, with my husband.” I am told that this attempted suitor was rather deflated upon hearing these words and did not utter any more until he had left.

And yes, I am fully aware that I took on a rather erudite tone in that last passage; perhaps I’ve been reading too much 19th century prose…





If I had known I would have baked a cake….

31 08 2007

Blog Day 2007

Happy Blog Day everyone! This is the 3rd annual celebration, and in keeping with the wishes set forth by those who’ve spread the word, I’ve picked five blogs that I regularly read and think you should, too. I was quite surprised to have been chosen as one of the five over at A Blog Around the Clock (thanks Coturnix!), and I’m going to carry on the meme in quite the same way by picking 5 of my favorites instead of just 5 “new” blogs. Envelope please…

Catalogue of Organisms – Chris admittedly has “An inordinate fondness for systematics,” and a wide range of interests that would have made E.D. Cope and other earlier naturalists proud. His posts are always well documented and researched, and it’s hard not to learn something new on any given visit. Plus, he was nice enough to tag me with the Thinking Blogger Award for a second time, so this is my way of saying “Thanks!”

Clastic Detritus – Brian is another good friend of mine who, in addition to just acquiring a spiffy new title and moving to wordpress, is the father of the new earth sciences blog carnival The Accretionary Wedge. He is far more well-versed in geology than I could ever hope to be, and I am glad that he is helping to lead the charge to get geo-bloggers more involved on the web.

Prehistoric Pulp – Walt reads ‘em so you don’t have to, or rather, Walt reads ‘em so you know which ones actually are pretty good so you know where to turn when you’re in the mood for some good paleo-fiction. Walt’s knowledge of the monsters (real and imagined) lurking in the pages of recent literature is encyclopedic, and his is a wonderful and well-written resource.

Thoughts in a Haystack – And I thought I spent a lot of time trying to understand the history of science. I have only recently discovered John’s blog, but it is an absolute treat to read and his writing is brimming with careful research, measured opinion, and an excellent sense of humor. If you’re not reading Thoughts in a Haystack yet, you darn well should be.

The Ethical Paleontologist – Where would I be without Julia? Outside of directing me to other people extremely helpful in my fields and interest and providing plenty of encouragement, Julia writes an excellent blog that ranges from her “Jurassic Garden” to songs about dinosaurs to her current journey to get her PhD. Her blog, simply put, is a must-read.

Also of note: My friend Zach’s blog When Pigs Fly Returns (if for no other reason that his excellent reconstruction of Arizonasaurus, and Pondering Pikaia, which was duly recommended by Coturnix and will likely be on many more lists.

So what are your five commendations for your readers? You can read all the “official rules” at the Blog Day website, but be sure to add a description as to why each of the blogs is so good. Go on, boost some egos and endorse good blogging wherever you may find it.

[Blog Day Technorati Tag]





The tooth is a big clue…

30 08 2007

It’s going to take a little while to get my latest paleo-post up and running, but in the meantime I thought I would put up a bit of a “teaser.” The following picture is of the remains of the skull studied and described by a persnickety British anatomist during the 19th century, and is the focus of my current project.

Skull

I can’t think of any sort of “prize” that I’d be able to give for anyone who correctly identifies the fossil, although the self satisfaction from figuring it out should be a pretty good ego-boost in-and-of itself.





It’s almost that time again…

30 08 2007

The next installment of the paleo-carnival The Boneyard is coming up this Saturday, and it will be hosted by my good friend Zach over at When Pigs Fly Returns. Be sure to send your submissions to him or to me by Friday evening if you want in on the osteological action.

Also, my friend Brian of Clastic Detritus (formerly …Or Something) has started a earth sciences-based carnival with the absolutely wonderful title of The Accretionary Wedge (it ranks right up there with Highly Allochthonous as a title). The first edition is all about how bloggers came to be interested in the earth sciences to begin with, so if you’re a geo-blogger be sure to contribute to this new conglomeration.

And, lest I forget, the anthropology carnival Four Stone Hearth is up at Hominin Dental Anthropology and Tangled Bank #87 is up at Balancing Life. I really need to get back on top of when carnivals are going up to get some more posts out there…





Waterlogged Weblog

30 08 2007

Evolutionary transitions into and out of the water (imaginary or real) have been a hot topic on this blog lately, so I thought I would provide the links to some of the posts from the past year on that theme. Hopefully I’ll be able to cover icthyosaurs, mosasaurs, plesiosaurs, and other critters in due time, but for now here are some aquatic-oriented works to keep you occupied;

Scuttling the Aquatic Ape Hypothesis

Everyone back in the pool!: From artiodactyl to cetacean

Protosuchus

Alligators? In the sewers?

A different kind of White Shark

Carnivory in Hippos

You can bring a Rhipidistid to land but you can’t make it walk

Idiocy beyond belief: Sharks don’t have webbed feet!

Bluffing in crayfish arm-wrestling

Skimming for supper, or not…

Giant Swimming Sloths of South America

An Iguanodon with flippers








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