Featured Spotlight: Elomeryx

10 10 2010

Good tidings and well-wishes and once again, I must apologize for my lengthy, school-induced posting drought!

As a result of my earlier posts on Coryphodon, Pezosiren, and Estemmenosuchus, it’s fair to say TTT has acquired a history of discussing semi-aquatic and superficially hippo-like animals (though Brian’s blog certainly has mine bested in this field). To shake things up just a wee bit for this particular ‘spotlight’, I’d like to shed some coverage upon Elomeryx sp., an animal which, shockingly, may actually be related to modern hippos! However, as we shall see, this particular creature is arguably much better known for its theoretical kinship with another group of contemporary mammals: the Cetacea (which is hardly surprising, for, as I’ve argued earlier, cetaceans are rapidly becoming the “nonavian theropods” of paleo-mammology).

A reconstruction originally compiled by Philip Gingerich wherein Elomeryx stands in as a model of the earliest artiodactylian ancestors of archaic whales.

Elomeryx is the oldest known constituent of the Anthracotheriidae, a family which, as defined by the genus’ arrival, first evolved in the Mid-Eocene of Eurasia. The group subsequently spread throughout both of the region’s continents along with Africa and, to a lesser extent, North America before its youngest known member, Merycopotomas, went extinct during the late Pliocene. Presumably, the group’s decline in the old world is the result of the spread of primitive hippos whilst their limited tenure in the western hemisphere has often been attributed to a lack of diversity and widespread alterations in habitat.

Elomeryx reconstruction

The Anthracotheriidae is divided into three subfamilies, the Anthracotheriinae, the Microbunodontinae, and the Bothriodontinae, with Elomeryx itself hailing from the latter assemblage. According to Donald G. Kron and Earl Manning, this group is defined on the basis of the following characteristics: “[C]anine tusklike; upper molar mesostyles fully invaded by transverse valley; mesostyle not forming a fully developed cusp in consequence; and ectoloph completely W-shaped.”  

E. crispus skull hailing from Southwestern France.

(Do check out this paper for more details on the above image)

Discovered by Othneil Charles Marsh during the famed “bone wars” of the late nineteenth century (on a side note, I’d most heartily recommend Mark Jaffe’s excellent book on the subject to those interested in this fascinating period of U.S. paleontology), Elomeryx is noteworthy for, among other things, its sexual dimorphism (though its hardly the only Anthracothere to exhibit such diversity in this regard): male specimens sport serrated posterior edges on their upper canines. Alongside this feature, the genus may be recognized by its short rostrum, five-cusped molars, looplike mesostyle, a diestemata-free premolar row, and the presence of accessory cusps on premolars in derived species. Intriguingly, some authors maintain that Elomeryx is paraphyletic, an assertion whose verification will require a more intensive study of North American specimens. The genus is generally considered to have been a consumer of freshwater vegetation on the basis 0f its dental morphology, though it should be noted that its relative lack of specializations render any effort to precisely reconstruct its lifestyle elusive at best.

Earlier, I treaded lightly whilst discussing the phylogenetic affiliations of the Anthracotheriidae. This discretion stems from the fact that these relations have become the focal point of considerable controversy in recent years. While essentially everyone is in agreement over the well-evidenced notion that hippos are the closest living relatives of cetaceans, the precise nature of this linkage is hardly “crystal clear”. The fact that the first Archaeocetes predate Elomeryx in the fossil record all but rules out the possibility that Anthracotheres could have given rise to these earliest of whales, depending, of course, on whether or not future fossil evidence will contradict this assertion. The situation is complicated further by a recent paper which argues that the Anthracotheriidae is akin to the Entelodontoidea and the enigmatic Andrewsarchus which, together, form the proposed Cetacodontamorpha lineage which, according to Michelle Spaulding, Maureen O’Leary, and John Gatesy, is defined as the “Cetancodonta plus all extinct taxa more closely related to extant members of Cetancodonta than to any other living species”.

My 2009 Booklist

31 12 2009

Good tidings and well-wishes!

In light of the fact that 2010 (and, by extension, the decade’s conclusion) is fast upon us, I’ve recently been forced to make my resolutions for the approaching year. These decisions are to improve my physical health & appearance and to increase my personal rate of literary consumption. While the confines of this blog inhibit my capacity to translate the former declaration into any sort of meaningful post, I’ve decided to erect an annual chronicle of each book I’ve read in the preceeding year so that I may better regulate the latter. Additionally, I hope that the following miniature reviews of the aforementioned books will prove to be useful to any of my readers who might consider reading them. Thus, without further ado, I humbly present this year’s entry (in chronological order):

NOTE: This list only contains those volumes which I’ve read cover to cover to the exclusion of those I’ve merely referenced (most of which can be found within the citations of earlier, more technical posts).

‘The Top 10 Myths About Evolution’ by Cameron M. Smith & Charles Sullivan

My Thoughts: If you’re already familiar with the most abundant ill-informed critiques of evolutionary theory, this book most likely isn’t for you. However, both authors receive an enormous amount of credit for re-articulating a number of concepts into terms anyone can understand.

‘Mind of the Raven’ by Bernd Heinrich

My Thoughts: I’ve already highlighted a few excerpts from this deliciously intriguing volume here. This has got to be one of the most philosophically stimulating ‘hard science’ books that I’ve read in quite some time, one which should force every reader to at least consider the idea that Homo sapiens is most certainly not the only form of intelligent life on this planet. My only substantial criticism is based upon Heinrich’s writing style which, while clear and coherent, contains an appreciable amount of undue rambling. Nonetheless, if you’re even remotely interested in psychobiology, ornithology, or naturalism in general, I wholeheartedly recommend this evocative book.

‘Mammoth’ by John Varley

My Thoughts: I don’t often read fiction, but when I do, my fodder of choice almost invariably falls within three categories: literature, philosophical thrillers, or sci-fi. I doubt that I’ll need bother mentioning by which title this novel is generally cited. I found it to be vastly entertaining, despite the fact that it inaccurately depicted a handful of its Pleistocene cast members.

‘Your Inner Fish’ by Neil Shubin

My Thoughts: This book is almost immeasurably more satisfying than the mere discussion of Tiktaalik roseae and its discovery I’d anticipated. Instead, it’s an exquisite introduction to the study of the evolutionary path upon which our bodies have traveled for the past 3.5 billion years which has been blessed with the amazingly readable prose of an obviously passionate author. Additionally, it clearly demonstrates that the human body, complex and engaging as it is, is far from perfect and is riddled with fairly obvious design flaws.

‘Mammoths: Giants Of The Ice Age’ by Adrian Lister & Paul Bahn

My Thoughts: I simply cannot think of a better volume through which to introduce the scientific study of the various Mammuthus species than this well-organized and masterfully illustrated compendium. However, I do wish that Lister and Bahn had included a more comprehensive review of early proboscidean evolution: although I realize that, as the title suggests, this wasn’t the point of the book, it would have been very much appreciated.

‘The Search for the Giant Squid: The Biology And Mythology Of The World’s Most Elusive Sea Creature’ by Richard Ellis

My Thoughts: This one was another recipient of its own review back in February, and my opinion of it has scarcely changed since then: had Ellis spent more time ‘covering the basics’ by further discussing the biology of cephalopods rather than dedicating a third of its textual content to essentially highlighting the giant squid’s celebrity status in pop-culture, it could have easily become an indispensible classic rather than the entertaining but ultimately hollow tome.

‘Ishmael’ by Daniel Quinn

My Thoughts: It’s been said that all novels are, in essence, philosophies expressed through an artistic venue. I can think of no better way to describe Dan Quinn’s ‘Ishmael’.  This is a fiercely intelligent cavalcade of earth-shattering philosophical observations guaranteed to spawn an immense amount of self-consideration long after its completion.

‘The Ghosts Of Evolution: Nonsensical Fruit, Missing Partners, And Other Ecological Anachronisms’ by Connie Barlow

My Thoughts: Barlow does an exquisite job of combining personal experience with scientific inquiry to create what can only be described as a highly thought-provoking review of one of the most interesting aspects of evolutionary biology which had me closely scrutinizing any produce I happened to come across for months thereafter.

‘New Rules: Polite Musings From A Timid Observer’ by Bill Maher

My Thoughts: Although I’ll readily concede that his well-documented disdain for Western medicine and crass overall attitude are simply inexcusable, I can’t deny the fact that Bill Maher often raises some excellent points via his televised program and stand-up routines. Nevertheless, this particular volume is naught but a greatly disappointing collection of recycled material, nearly all of which can be found on Youtube.

‘Moral Minority: Our Skeptical Founding Fathers’ by Brooke Allen

My Thoughts: This is required reading for anyone who has even considered becoming involved in the ongoing controversy about the desired strength of church/state separation in the U.S. Allen completely obliterates the mythology surrounding the concept and its annals by providing an arsenal of historical evidence against such unsubstantiated claims as ‘the founding fathers were deeply religious men’ (the most influential ones were primarily deists, agnostics, and universalists), and ‘the United States was founded as a Christian nation’.

‘Why Evolution is True’ by Jerry Coyne

My Thoughts: From now on, when anyone asks me for a fairly comprehensive overview of the evidence for evolution, Jerry Coyne’s new book is the first thing I’ll suggest. Coyne utilizes examples I’d never heard or thought of to make monstrously-effective points which expose the reader to the absolutely mountainous evidence which supports the theory of evolution and by extension, shows him or her precisely why the scientific community accepts it on a universal scale.

‘The Moral Animal (Why We Are The Way We Are): The New Science Of Evolutionary Psychology’ by Robert Wright

My Thoughts: I have to say that, even in the face of such worthy competitors as ‘Your Inner Fish’, ‘Mind Of The Raven’, ‘The Selfish Gene’, and ‘Ishmael’, this was by an appreciable margin the most evocative and eye-opening book I’ve read this year. Evolutionary psychology is easily one of the most controversial subjects in modern science, recruiting such prestigious supporters as Richard Dawkins and Stephen Pinker and such eminent adversaries as Stephen Jay Gould. Wright does a superb job of introducing the reader to this unambiguously captivating, yet divisive, topic. He also earns extra credit in my opinion for highlighting the philosophical struggle which accompanies the discipline by providing a detailed discussion about why the way things are isn’t necessarily the way they ought to be while simultaneously defending a personal allegiance to John Stuart Mill’s utilitarianism.

‘Carl Sagan: A Life In The Cosmos’ by William Poundstone

My Thoughts: It’s no secret that I’m an enormous Carl Sagan fan. As an avid proponent of increasing and improving science communication aimed at the public, I can’t think of a better model upon which to base my own efforts than this eloquent messenger of the cosmos. Poundstone’s comprehensive biography delves beyond the mystery to reveal not only an entirely human story behind the scientific celebrity, but also some of the most destructive and divisive forces and biases which inhabit the scientific community itself.

‘The Selfish Gene’ by Richard Dawkins

My Thoughts: Though I don’t particularly care for his aggressiveness on the subject of religion, Dawkins is an excellent writer: a contention which, I feel, can be substantiated more effectively by no volume of his other than ‘The Selfish Gene’, which remains one of the most influential books in the history of modern evolutionary biology over three decades after its publication. However, due to the massive exposure the volume’s central concepts have been given by a plethora of subsequent narratives, they didn’t really offer me a challenge when read in their original context. Still, I found “The Selfish Gene” to be well worth my while.

‘Notre Dame de Paris’ (aka: ‘The Hunchback of Notre Dame’) by Victor Hugo

My Thoughts: I opted to read this one after hearing wonderful things about Hugo’s work from my well-read friends and later growing addicted to the song ‘Heaven’s Light/Hellfire’ from the Disney adaptation (the beautiful lyrics and animation of which force me to excuse the indefensibly-comical statues that occupy the first quarter of the piece). This oft-discussed novel has utterly dazzled me, and I now consider Hugo to be one of my favorite authors, for I can think of very few writers who can hope to compete with him in the art of mounting suspense and perfectly capturing the intricacies and subtleties of human emotions. Nowhere is this latter skill more apparent than in Hugo’s execution of Archdeacon Frollo, a complex and somewhat tragic character who fully deserves a place in any discussion regarding the greatest literary villains of the previous millenium.

‘Why Geese Don’t Get Obese (And We Do): How Evolution’s Strategies For Survival Affect Our Everyday Lives’ by Eric P. Widmaier.

My Thoughts: Though I fully realize that the two sciences are fundamentally intertwined, I’ll admit that I’ve always found anatomy to be far more interesting than physiology. Having made such a contention, I can’t help but feel far more enthusiasm for the latter discipline following the conclusion of this readable and passionate compendium. Widmaier clearly adores his area of expertise and has given it’s broader scientific implications a great deal of thought, as evidenced not only by the book’s introduction and epilogue, but nearly every paragraph of its being. However, this esteem appears to be somewhat reserved for physiology to the exclusion of certain other fields, as Widmaier occasionally exhibits factual errors when discussing paleontology (such as claiming that Dimetrodon was a dinosaur) . Still, this is a minor point which no way prevents me from highly recommending ‘Why Geese Don’t Get Obese’ to anyone with an interest in the biological sciences.

Happy new year and may the fossil record continue to enchant us all!

TTT’s Saturnalia Special

23 12 2009

Good tidings and well-wishes and happy holidays!

Since the holiday season is fast upon us (if it hasn’t already arrived for some of us), I felt that my humble corner of the internet display a wee bit of a festive tribute to this ‘most wonderful time of the year’, with a slight twist of course. Below, you’ll find a collection of holiday decorations and excerpts designed to appeal to the nerdiest of web surfers. As a firm believer in giving credit where it’s due, I’ve also attached links to the posts and web pages from whence they’ve come and would encourage everyone to view them in their original context to support the primary uploaders. So grab a cup of ‘cheer’ (whatever that is), open your textbooks and enjoy!

To kick things off, Jen McCreight, author of the ever-popular ‘Blag Hag‘ and president/co-founder of the Purdue Non-Theists Society has presented the following  illustrative evidence in favor of the idea that Santa is in for some competition this year:

And, through the miracle of modern capitalism, one can readily obtain mugs, t-shirts, and other products depicting this most festive of displays from Jen’s online store.

Despite the fact that its content doesn’t exactly conform to that which has generally become associated with this blog, I simply cannot deny my love of CBS’ ‘The Big Bang Theory’. Below, I’ve re-posted an unofficial highlight reel of the show’s Christmas special which was released last December.

What’s Christmas without the decorations? Recently, I’ve stumbled upon this post which highlights a series of nerdy Christmas ornaments, my favorite of which 9despite my hatred of mathematics) can be seen below.

Right then, back to paleontology! Paleo nerds aren’t generally difficult to buy for, but should you find yourself in want of a paleontological gift idea, ReBecca “Dinochick” Hunt-Foster has brought to the blogosphere’s attention what is quite possibly the coolest series of stuffed animals ever manufactured: the Evolvems!

"From Fish To Tetrapod!"

According to the official web-page,

Unzip and flip the creature inside out and you’ll get its evolved form. Watch fins turn to feet and gills grow into lungs right before your eyes. The best part is that all you kids who want to see ’em don’t have to line up at our museum. You can have your own piece of evolution in your own home and bring it in for show n’ tell at school. Show those other monkeys their roots, we say.”

The line contains CoelocanthIchthyostega (pictured), DimetrodonCynognathus, YinlongStyracosaurus, and my personal favorite, PakicetusSqualodon.

Having successfully regurgitated pieces of saturnalia flare from round the world wide web, I feel that this post would be incomplete without providing one of my own. So, in Darren Naish style, I now offer my readers a bit of a geeky puzzle. In honor of everyone’s favorite levitating holiday cervid, I now present ‘TTT’s first annual ‘Winter Solstice Mystery Artiodactyl‘ contest.  The first reader to correctly identify the following even-toed ungulate via sending me their entry through the ‘comments’ section, my personal e-mail account, or any other means available to them will receive an automatic thumbs-up from yours truly along with a shout-out at the onset of my next post. With that, I present your beastie:

Io Saturnalia everyone and, as always, may the fossil record continue to enchant us all!

Week Of Wonders: Coryphodon

16 12 2009

Good tidings and well-wishes!

When asked to cite my favorite sub-discipline of biology by interested parties, I often find myself at an uncharacteristic loss for words. As an academic marriage of geology and bio, my beloved field of paleontology certainly can’t qualify as a finalist for this distinction. This fact results in a three-way tie between evolutionary studies (which, I hardly need tell my fellow nerds, covers an enormous intellectual area), psychobiology (which nicely combines my love of the humanities and social sciences with my passion for evolutionary biology), and the centuries-old subject of comparative vertebrate anatomy.

This latter science is a beautiful thing in that it so very often lends an enormous amount of scientific credence to the notion that ‘looks can be deceiving’. For the proponents of this science have shown that their beloved domain can do much more than assist us in our efforts to ascertain the identities of the various chimeras which have proclaimed their existence to the scientific community through the ages: it can also reveal that those creatures which, at first glance, appear to be entirely mundane are actually far more interesting than anything which we could have possibly imagined. Last spring, I utilized this column to feature the strange case of Sivathertium: a moderately-large giraffid which, according to most any initial inspection, resembled a moose with an elongated skull. Nearly six months later, I’d like to draw the attention of my readership to the anatomical story of another bizarre animal: Coryphodon sp. of the Eocene.

Let’s begin by examining the animal’s skeleton as displayed below:

Coryphodon sp. Skeleton (Courtesy of Wikipedia)

Mammal enthusiasts are likely to assume that this beastie was merely a type of prehistoric Hippopotamus as suggested by its relatively stout limbs, barrel-like chest, and fearsome jaws.

However, perhaps we should now compare it to a skeleton of an actual Hippopotamus:

The two aren’t exactly uniform in composition, are they?

In their excellent book, “Mammoths, Sabertooths, And Hominids: 65 Million Years Of Mammalian Evolution In Europe”, Jordi Augusti and Mauricio Anton write:

“the skeleton of Coryphodon [is] a mixture of traits reminiscent of those of different kinds of animals. The trunk vertebrae have surprisingly weak neural spines for such a big animal [(Coryphodon was approximately 1 meter in height and 2.25 in length)], suggesting a partly amphibious lifestyle, like that of modern hippos. The long bones of the limbs resemble in structure those of heavy perissodactyls like rhinos and tapirs, while the feet, retaining all five digits, are like those of modern elephants in structure. In side view, the head vaguely resembled that of the Paleocene arctocyonids, with huge canines, although this animal was not an omnivore like the latter, but a specialized vegetarian.”

Coryphodon foot reconstruction, which, as the authors have pointed out, really resembles that of an elephant more than anything else.

Although Coryphodon certainly bore distinct resemblances to various members of the artiodactyla, perissodactyla, proboscidea, and arctocyonidae, this intriguing herbivore owed its phylogenetic allegiance to none of these groups. So what the hell was it?

The animal actually belonged to the extinct order pantodonta: one of the first groups of herbivorous mammals to truly attain relatively large sizes.  A list of the group’s distinguishing characteristics may be located here.

Restorations of some pantodonts of the North American Paleocene. A. Coryphodon. B. Barylambda. C Titanoides primaevus. D. Caenolambda. E. Pantolambda cavirictus. E. Pantolambda bathmodon. (Courtesy of paleocene-mammals.de)

As the preceeding image indicates, pantodonts were a wonderfully diverse lot despite their aforementioned similarities. While our hippo-like Coryphodon likely behaved in the manner of the modern creature to which its skeleton was compared at the onset of this article, Barylambda was built like an eccentric ground sloth and likely acted accordingly, Titanoides was a fairly large terrestrial herbivore whose dietary habits largely consisted of tough vegetation, and Pantolambda was a vaguely cat-like creature which nevertheless maintained an herbivorous diet. For an immeasurably more complete description of these incredible organisms, do go here.

A behind-the-scenes look at the Coryphodon cranial reconstruction which was recently employed at the AMNH's recent 'Extreme Mammals' exhibit.

There are certainly many more questions to be answered concerning this magnificent group of creatures (most notably, that of ‘to what other congregation of mammals is the pantodonta most closely related?’), and one would hope that they will soon be answered with the advent of additional research and a host of rising specialists.

May the fossil record continue to enchant us all!