The Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them by Don Prothero is available now for pre-order, and is expected to hit the shelves in mid July. It will provide excellent summer reading!

You know of Prothero because of his many books including the current classic (now in its second edition) Evolution: What the Fossils Say and Why It Matters. The “25” genera includes The Story of the Earth in 25 Rocks: Tales of Important Geological Puzzles and the People Who Solved Them, and The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution.

This book has a chapter devoted to each discovery. The nature of the discovery varies, and the definition of discovery is, necessarily and helpfully, very wide ranging. In many cases, the discovery, recovery, eventual reporting or publication, and integration of a dinosaur species is a long and drawn out process involving multiple field trips, many different characters, and a lot of action. For example, the “discovery” of spinosaurus (from Egypt) comes to us as a story involving two world wars, several expeditions, great human tragedy, and some cool dinosaur bones. Other discoveries are more about how we think about dinosaurs. This is especially true of the first few chapters, which serve to illustrate how clueless early researchers were about certain things, while being pretty smart about other things.

Chapter 6, on Eoraptor, focuses not on a specific discovery, but rather, on the question of what a dinosaur actually is, how taxonomy has changed, and on attempts to identify and define the basal dinosaur (which is not Eoraptor, but it kinda is). There are other similar orienting pauses elsewhere in the book as well.

Although the chapters vary a great deal in the range of time, space, or fossil material covered, they follow a general pattern of putting together in one place most of the pertinent facts about a particular episode in the history of dinosaur research, and the pertinent facts about a particular part of the overall dinosaur bestiary. All in all, there is a good bit of history, history of the science, anatomy, evolutionary biology, scientific drama, greatness and tragedy of the act of discovory (or loss), and many many bones.

It is important for you to know that Prothero brings the reader up to date on many, probably most, of the current dinosaur controversies and conundra. The Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them is divided into four sections. The first is about early finds and early thinking, from the dark ages of dinosaur research. The second focuses on the long-necked giants, the third on theropods, and the fourth on the ornithischians (duck beaked, horned, and spiky armored dinosaurs). I’ve put a current draft of the TOC at the bottom of the post to give you an idea of the detail of coverage.

I highly recommend this book.

Also by Prothero: When Humans Nearly Vanished: The Catastrophic Explosion of the Toba Volcano, Reality Check: How Science Deniers Threaten Our Future, UFOs, Chemtrails, and Aliens: What Science Says, The Princeton Field Guide to Prehistoric Mammals (Princeton Field Guides), California’s Amazing Geology, and coming out in the future: Fantastic Fossils: A Guide to Finding and Identifying Prehistoric Life, and a bunch of other books.

TOC:
Part I. In the Beginning
1. Megalosaurus: The “Great Lizard,” the “Scrotum Humanum”, and the First Named Dinosaur
2. Iguanodon: Gideon Mantell, Louis Dollo, and the First Dinosaur Fauna
3. Cetiosaurus: The “Whale Lizard,” Richard Owen, and the First Known Sauropod
4. Hadrosaurus: Joseph Leidy and the First American Dinosaur
5. Eoraptor: The First Dinosaurs
Part II. The Long-Necked Giants
6. Plateosaurus: Ancestors of the Giants
7. Apatosaurus and Brontosaurus: Marsh, Cope, and the Bone Wars
8. Diplodocus: The Real “Jurassic Park” and Carnegie’s Gift
9. Giraffatitan: The Tallest of the Tall, and the Tendaguru
10. Patagotitan: Who’s the Biggest of Them All?
Part III. Red in Tooth and Claw: The Theropods
11. Coelophysis: The Little Dinosaur of Ghost Ranch
12. Cryolophosaurus: Denizen of the Polar Darkness
13. Spinosaurus: Lost Giants of Egypt
14. Tyrannosaurus: King of the Tyrant Reptiles
15. Giganotosaurus: Biggest Predator of All?
16. Deinocheirus: “Terrible Hands” Lead to Big Surprises
17. Velociraptor: “Terrible Claws” and the Dinosaur Renaissance
18. Sinosauropteryx: Feathered Dinosaurs and the Origin of Birds
Part IV. Horns and Spikes and Armor and Duck Beaks: The Ornithischians
19. Heterodontosaurus: The Origin of Ornithischians
20. Stegosaurus: The “Roofed Lizard” and the Thagomizer
21. Ankylosaurus: Armored Dinosaurs and “Mr. Bones”
22. Corythosaurus: Duckbills with Headgear
23. Stegoceras: The “Unicorn Dinosaur” and the Boneheads
24. Protoceratops: The Griffin Legend and the Origin of Horned Dinosaurs
25. Triceratops: The “Dinosaurian Bison” and the Last of the Dinosaurs

The word comes from the ancient Greek for “Fish Lizard.” One wonders what they were smoking.

But seriously, this category of creature is an entire order unto itself, part of the Reptile class. They first appear in the fossil record around 250 million years ago, and dwindled into extinction about 90 million years ago. There origin occurs at about the same time as the beginning of the Triassic, becoming diversified and abundant by the end of the triassica nd early Jurassic.

Very little is known about how the Ichthyosaur first evolved from a land-based reptilian stock. A separate group, called the Hupehsuchia, date to the very early Ichthyosaur times, and resemble them, but with distinct differences. Hupehsuchia did not last very long. It is likely that Hupehsuchia represent a link between an unknown pre-aquatic reptile and actual Ichthyosaurs, in indirectly, and arose from near the base of the Ichthyosaur linage. This is debated.

But never mind, for now, the early beginnings of the enigmatic fish lizard. Consider instead what it ended up becoming. Even early in their evolutionary history, Ichthyosaurs really do resemble modern day toothed whales, especially the dolphins and porpoises. Here are the skeletons of an Ichthyosaur and a Dolphin compared.

The differences are not small, but they relate more to the underlying skeletal patterns in reptiles vs mammals. For example, reptiles have a lot of vertebra and thus ribs, and the number seems to vary evolutionary across genera as needed, while mammal vertebrae and rib patterns are much more constrained. Also, those weird sclerotic plates in the eyes … these are eye bones found across vertebrates but not mammals (or crocodilians).

So, Ichthyosaurs are basically reptilian dolphins in overall appearance. It turns out they are dolphinesque in another important way as well, according to just published research.

In Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur by Yohan Lindgren, Peter Sjövall, Volker Thiel, Wenxia Zheng, Shosuke Ito, Kazumasa Wakamatsu, Rolf Hauff, Benjamin P. Kear, Anders Engdahl, Carl Alwmark, Mats E. Eriksson, Martin Jarenmark, Sven Sachs, Per E. Ahlberg, Federica Marone, Takeo Kuriyama, Ola Gustafsson, Per Malmberg, Aurélien Thomen, Irene Rodríguez-Meizoso, Per Uvdal, Makoto Ojika & Mary H. Schweitzer, we learn:

Here we show that this resemblance [to Dolphins] is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life.

So they may have been homeothermic (warm blooded, more or less). They may also have had countershading seen in today’s fishy and other swimmy things, with a lighter belly and darker flanks. This may have served as both camouflage and protection from UV light.

The paper was published in Nature.

There is no evidence of life on Mars right now.

NASA just discovered what looks to human palaeontological eyes just like trace fossils, of organisms burrowing through or living in mud, a long time ago. Further study is under way. Meanwhile, this is what the rock of interest looks like:

The trace fossil looking things would be the semi-squiggly darkish tubes shown here in this somewhat blurry blow-up:

Those could be mineral deposits that formed in mud in the absence of any living organism. NASA’s info on this find is here.

On a planet with life, these look like some evidence of that life. On a planet that never had life, these look like natural mineral concretions. But if only life could be so simple!

In my own personal experience, these look closest to iron or manganese (or both) deposits that form in bogs. However, that does not mean that they look to me like natural concretions, because I’m pretty sure that those bog deposits occur with the help of bacteria. In other words, trying to figure out what these Martian items are by reference to “natural mineral concretions” on Earth is going to be more problematic than people may be thinking, because such mineral concretions are often signs of life on our planet even if they are not, themselves, specifically, direct fossils or traces of living organisms.

But here is the thing that I find interesting: The chances that this photograph represents life on Mars is either very high or very low in the eyes of a given observer depending on the answer to this question: How likely to you think life is to begin with? If you think life is very likely to emerge where there are things like sunlight or a chemical source of life-usable energy, and liquid water, is very very high, then we can be pretty certain that Mars at one time had life, and we are simply waiting for NASA to find it. It would be a surprise to NOT find it eventually, and since evidence absent is hard evidence to parse without resorting to useless aphorisms, we’ll just have to wait a long time before giving up on the idea. Alternatively, if you think that life is very unlikely to get started given the basic raw materials, so that what we have on Earth is special and rare, then you should be very agnostic about anything that comes along in the way of lifey-looking stuff from the angry red planet.

But here is the other thing. Which way a particular individual, especially a scientist and especially a NASA scientist, is actually going to break on this has less to do with gut feeling or understanding the origin of life or any of that, than it has to do with worrying that people are going to think you are nuts.

As a person who fully expects that life is likely (generally speaking), and therefore, that it probably emerged on Mars at some point, in some form, here is what I think is going to happen:

Scientists will remain publicly agnostic about life ever existing on Mars. They will become annoyed at anyone that suggests otherwise, but they will always leave the possibility open. They will give a little more wiggle room for a singe celled bacteria like form of life, and bridle at any suggestion of multi-celled life (if these are “trace fossils” that’s multi-celled life, if it was Earth). They will also get mad at anyone who discuses life on Mars mainly in terms of multi-celled life, as thought such an interlocutor was dissing the poor Martian bacteria. Which we shall remain agnostic about.

Then we’ll find definitive evidence of life on Mars. It may be bacteria-like, or it may include colonial or basic multi-cellular forms. Or something else. Whatever.

Then, since the two planets we a) know about and b) can reach, have evidence of life, we’ll thereafter assume life is easy, as it were, and widespread in the Universe, and eventually, only historians will remember when we thought differently!

I just hope that those squiggles aren’t dirt that fell out of the Mars rover’s treads as it went by this site at an earlier time.

Let’s start off with a kid’s book: Grandmother Fish: a child’s first book of Evolution by Jonathan Tweet.

From the blurb:

Grandmother Fish is the first book to teach evolution to preschoolers. While listening to the story, the child mimics the motions and sounds of our ancestors, such as wiggling like a fish or hooting like an ape. Like magic, evolution becomes fun, accessible, and personal. Grandmother Fish will be a full-size (10 x 8), full-color, 32-page, hardback book full of appealing animal illustrations, perfect for your bookshelf. US publishers consider evolution to be too “hot” a topic for children, but with your help we can make this book happen ourselves.

I reviewed the book here before it first came out. This was a kickstarter project, and it may be currently unavailable commercially, but if you click through to the kickstarter project you can probably get a copy of it.

The most recent book to come across my desk is Don Prothero’s The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution. I’ve got a review of Prothero’s book in my draft file, so look for that post coming out over the next few days.

One might ask, “how do you choose 25 fossils, among so many choices, to represent evolution?” Well, Don cheated a little by mentioning more than 25 fossils. Also, you really can’t do this. Don selected fossils using several criteria, but one basis for his choice was the availability of rich historical information about a fossil’s discovery, interpretation, and effect on our thinking about evolution. And, he covers all of that.

Don is one of those rare authors who is both an expert scientist and a great writer, with a proven ability to explain things in a way that is not watered down yet totally accessible.

Here’s a selection of the many other books written by Prothero:

• Abominable Science!: Origins of the Yeti, Nessie, and Other Famous Cryptids

• After the Dinosaurs: The Age of Mammals (Life of the Past)

• Catastrophes!: Earthquakes, Tsunamis, Tornadoes, and Other Earth-Shattering Disasters

• Greenhouse of the Dinosaurs: Evolution, Extinction, and the Future of Our Planet

• Rhinoceros Giants: The Paleobiology of Indricotheres (Life of the Past)

• Evolution: What the Fossils Say and Why It Matters by Prothero, Donald R. 1st (first) Edition [Hardcover(2007)]

Evolution: The Whole Story is an astonishing book that needs to be on the bookshelf of anyone interested in evolution. The work is edied by Steve Parker, but authored by nearly a dozen experts in various subfields of fossils and evolution, so it is authoritative and scholarly. At the same time, it is very accessible and enjoyable. This is not a book you read from cover to cover, though you could. Feel free to skip around, and you;ll find yourself looking stuff up all the time.

The book is divided into major sections, and each section has a series of short pieces on this or that fossil, group of fossils, type of life system, method for studying fossils, etc. There is a running sidebar on the bottom of many pages giving “key events” in evolutionary history of the group of life forms under consideration The book is VERY richly illustrated, with detailed keys to the illustrations. Many of the illustrations are broken down into “focal points” that expand significantly on the illustrations’ details. There are countless additional inserts with more information. The book itself is beautiful, intriguingly organized, and it is full of … well, everything. The book is very well indexed and sourced, and has helpful, up to date, phylogenies and chronological graphics.

The Biology Book: From the Origin of Life to Epigenetics, 250 Milestones in the History of Biology (Sterling Milestones) by Michael Gerald and Gloria Gerald is a compendium of biological topics and key moments in the history of biological science, organized in a sort of chronological framework. Major groups (the insects, the amphibians), major ideas (Pliny’s Natural History, Ongogeny and Phylogeny), key physiological and developmental concepts (meiosis, mitosis, many topics in endocrinology), key fossils (like the Coelocanth) and so on are discussed, very nicely illustrated. This is almost like having a gazillian short articles from Natural History Magazine (or similar) all in one book. There are 250 biological “milestones” in all. The charming part of the book is that a milestone can be an evolutionary event, an extinction episode, the emergence of a great idea, or a particular discover. And, as noted, these are ordered across time, as well as one can, from the beginning of life to a selection of the most recent discovery. The book effectively combines history of biology (and related sciences) and the biological history itself.

Life’s Greatest Secret: The Race to Crack the Genetic Code by the well respected scientist and historian Matthew Cobb is a carefully and clearly written history of the discovery of the nature of DNA, covering a lot more than, and since, Watson and Crick. It is extremely well sourced, indexed, and supported, and very readable.

This is the detailed and authoritative work on all the elements that came together to understand the genetic code. Don’t talk about the discovery and understanding of DNA any more until you’ve read this book. From the publisher:

Life’s Greatest Secret mixes remarkable insights, theoretical dead-ends, and ingenious experiments with the swift pace of a thriller. From New York to Paris, Cambridge, Massachusetts, to Cambridge, England, and London to Moscow, the greatest discovery of twentieth-century biology was truly a global feat. Biologist and historian of science Matthew Cobb gives the full and rich account of the cooperation and competition between the eccentric characters—mathematicians, physicists, information theorists, and biologists—who contributed to this revolutionary new science. And, while every new discovery was a leap forward for science, Cobb shows how every new answer inevitably led to new questions that were at least as difficult to answer: just ask anyone who had hoped that the successful completion of the Human Genome Project was going to truly yield the book of life, or that a better understanding of epigenetics or “junk DNA” was going to be the final piece of the puzzle. But the setbacks and unexpected discoveries are what make the science exciting, and it is Matthew Cobb’s telling that makes them worth reading. This is a riveting story of humans exploring what it is that makes us human and how the world works, and it is essential reading for anyone who’d like to explore those questions for themselves.

Extinction and Evolution: What Fossils Reveal About the History of Life is a an updated version of a classic book about evolution and extinction written by one of the scientists who developed our modern way of thinking about evolution and extinction (especially the extinction part).

Eldredge’s groundbreaking work is now accepted as the definitive statement of how life as we know it evolved on Earth. This book chronicles how Eldredge made his discoveries and traces the history of life through the lenses of paleontology, geology, ecology, anthropology, biology, genetics, zoology, mammalogy, herpetology, entomology and botany. While rigorously accurate, the text is accessible, engaging and free of jargon.

Honorable Mentions: Older books that are great and may now be avaialable for much reduced prices.

I really liked The Great Transition: Shifting from Fossil Fuels to Solar and Wind Energy as an expose of a particular time period and major event in geological history. Greenhouse of the Dinosaurs: Evolution, Extinction, and the Future of Our Planet by Prothero is a classic, again, looking at a fairly narrowly defined moment in prehistory. You can get it used for about five bucks.

The Fossil Chronicles: How Two Controversial Discoveries Changed Our View of Human Evolution by Dean Falk is a great book focusing on one key human fossil. This is a personal story as well as a scientific one. Again, available used for a song.

Have you read Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body yet? I’m sure you’ve heard about it. It is still a great read, and you can get it used cheap.

The only book I would recommend that uses the “paleolithic” to advise you on diet and exercise is The Paleolithic Prescription: A Program of Diet and Exercise and a Design for Living.

The last Giants’ was hosted at The Questionable Authority, here. The next issue will be hosted at The Evilutionary Biologist: All Science, All The Time, which resided here.

Since this is Darwin Month in Darwin Year and almost, indeed, Darwin Day, we start with … Paleontology. We’ll get to Darwin at the end.

Early palaentologists and the Giant killer lungfish from Hell as well as the Revenge of the Giant Killer Lungfish from Hell, at Laelaps, serve as instructive historical arguments worth a read by any paleontologist, fishy or otherwise.

Today, “spooky” in physics means stuff that happens at the smallest scales with photons and other subatomic bits and pieces. But back in the 18th and 19th centuries, simple electricity and magnetism was sufficiently spooky to keep everyone busy. Skullsinthestars writes about the complex history of discovery of the connection between the two, revealing a complex plot involving Faraday, Morichini, Somerville and the rest of them: A physics history-mystery: magnetism from light? Also from Skulls we have “Do optics like Darwin’s Dad!” The same author also has an historical look at the role of Evolution in pulp fiction, here.

We’re coming up on the golden anniversary of some very important experiments that were milestones in confirming relativity and were enabled by a breakthrough in nuclear physics, the Mossbauer effect. Mossbauer’s discovery (published in 1958) of the Mossbauer effect … Read about this in Testing Einstein at Swans on Tea.

The Aetosaur Paper That Changed Everything is very interesting foray into nineteenth century (and later) palaeontology, implicating everyone from Agassiz to Cope to B.J. Small, posted at Chinleana.

Ninja Cats are a recent phenomenon, but the question of the moon’s influence on human behavior has a long history. PodBlack Cat explores this literature: Ninja Kittens Don’t Steal The Moon – Crime Rates And Lunar Phase Research

An excellent post on how the heck alloys work, which in turn is based on models developed during the pre-WWII days, is posted at Materialia Indica: Classics in Materials Science: The Bragg-Williams model of order-disorder transformations.

John J. McKay has produced a tour de force series of blog posts on the history of everything, tied together with the theme of a mysterious specter haunting Europe and Asia from the late seventeenth century onward. “Some said it was a monster that lived underground; others said it lived in the water. No one had seen it alive. It was said to die on exposure to sunlight or air. All, however, agreed that it was an enormous beast–bigger than anything known–and that it had teeth (or horns) longer than a man. The natives called it ….” Click here to find out. And here, here, here, and here. Oh, and here. This is really great stuff. It should be a book!

It seems that almost every important thread of biological research eventually runs through the world of birds at some point or another. Grrrrrrrrrrrl Scientist speaks to this in particular with regards to species radiations in her post: Meet the Great Speciators: The White-Eyes

A book review for you: Tides of History by Michael S. Reidy at The Dispersal of Darwin Blog. … “I received this book from the publisher last year, so I am now finally able to put up my review. But I also had to read it for my current graduate class on historical writing, taught by Michael Reidy (my advisor and the author of the book!).” What luck!

Everybody hates Francis Bacon. Srsly. Chris Mooney covers this, so far, in Part I and Part II of a post of the same name.

Ah, now on to Darwin. We start with Larry Moran, who claims to not really be a Darwinist, Re-reading the Origin of Species. Then we move on to yours truly, re-reading the Voyage of the Beagle.

Then we have Mike Dunford, on Darwin, Experimentalist.

A Primate of Modern Aspect blog discusses Darwin, The Descent of Man, and Human Evolution

This just in from SciCurious: Friday Weird Science: Of Testicles and Cocks

reposted

In the vicinity of Rio Tercero…

Hearing … of the remains of one of the old giants, which a man told me he had seen on the banks of the Parana, I procured a canoe, and proceeded to the place. Two groups of immense bones projected in bold relief from the perpendicular cliff [but] I could only bring away small fragments of one of the great molar-teeth … sufficient to show that the remains belonged to a species of Mastodon. The men who took me in the canoe, said they had long known of them, and had often wondered how they had got there: the necessity of a theory being felt, they came to the conclusion, that … the mastodon formerly was a burrowing animal!

In remote St. Fe …

A tooth which I discovered … interested me much, for I at once perceived that it had belonged to a horse. Feeling much surprise at this, I carefully examined its geological position, and was compelled to come to the conclusion, that a horse, which cannot … be distinguished from the existing species, lived as a contemporary with the various great monsters that formerly inhabited South America. Mr. Owen and myself, at the College of Surgeons, compared this tooth with a fragment of another, probably belonging to the Toxodon, which was embedded at the distance only of a few yards in the same earthy mass. No sensible difference in their state of decay could be perceived; they were both tender, and partially stained red. … Certainly it is a marvellous event in the history of animals, that a native kind should have disappeared to be succeeded in after ages by the countless herds introduced with the Spanish colonist! But our surprise should be modified when it is already known, that the remains of the Mastodon angustidens (the tooth formerly alluded to as embedded near that of the horse, probably belonged to this species) have been found both in South America, and in the southern parts of Europe.

Weighty considerations of the distribution of extinct and extant fauna lead Darwin to the neighborhood of modern geological concepts.

Very few species of living quadrupeds, which are altogether terrestrial in their habits, are common to the two continents, and these few are chiefly confined to the extreme frozen regions of the north. The separation, therefore, of the Asiatic and American zoological provinces appears formerly to have been less perfect than at present. The remains of the elephant and of the ox have been found on the banks of the Anadir (long. 175° E.), on the extreme part of Siberia, nearest the American coast: and the former remains, according to Chamisso, are common in the peninsula of Kamtschatka. On the opposite shores, likewise, of the narrow strait which divides these two great continents, we know, from the discoveries of Kotzebue and Beechey, that the remains of both animals occur abundantly: and as Dr. Buckland has shown they are associated with the bones of the horse, the teeth of which animal in Europe, according to Cuvier, accompany by thousands the remains of the pachydermata of the later periods. With these facts, we may safely look at this quarter, as the line of communication (now interrupted by the steady progress of geological change) by which the elephant, the ox, and the horse, entered America, and peopled its wide extent.

Now, here we have Darwin on the verge of understanding the rise of the Panama Land bridge (or something like that) based on the biogeography. The above passage, the following passage, and other material is very frustrating. If Darwin was not such a geological gradualist he could have advanced geology to the 1950s with a single fell swoop of reasoning!!!!

The occurrence of the fossil horse and of Mastodon angustidens in South America, is a much more remarkable circumstance than that of the animals mentioned above in the northern half of the continent; for if we divide America, not by the Isthmus of Panama, but by the southern part of Mexico, .. where the great table-land presents an obstacle to the migration of species, … we shall then have two zoological provinces strongly contrasted with each other. Some few species alone have passed the barrier, and may be considered as wanderers, such as the puma, opossum, kinkajou, and peccari. The mammalogy of South America is characterized by possessing several species of the genera of llama, …, tapir, peccari, opossum, anteater, sloth, and armadillo. If North America had possessed species of these genera proper to it, the distinction of the two provinces could not have been drawn; but the presence of a few wanderers scarcely affects the case. North America, on the other hand, is characterized by its numerous rodents, and by four genera of solid horned ruminants, of which section the southern half does not possess a single species.

Just so you know, South and North America were separated, and had largely independent mammalian evolution (and migration), until very recently, about five million years ago, when the isthmus of Panama was raised.

Darwin is seeing the very time-deep echo of this event, masked by subsequent migration of North American mammals in to South America, and clouded by the more pressing (to him) question of Old World and New World relationships.

It is interesting that the monkey’s (appearing in both the old world and new world tropics) don’t freak him out. They freak me out.

Visit The Beagle Project Blog

Bahia Blanca is a port at the northern end of Patagonia. Chapter V of The Voyage begins:

THE Beagle arrived on the 24th of August, and a week afterwards sailed for the Plata. With Captain Fitzroy’s consent I was left behind, to travel by land to Buenos Ayres.

I tried Googling that … using “get directions.” Google maps was unable to compute a route. In fact, Google Maps has no roads whatsoever in Argentina. But, I was able to make a map showing the two locations, to give you an idea of what this must have been like. Darwin walked (well, there were horses) between these two points:

And along the way, he found some fossils. Here are brief excerpts describing some of his finds. As you read through this (it’s long, but I’ve tried to edit it down as much as possible) keep in mind the following things: Evidence for evolution, climate change, large scale global synthesis, connections between observations and theory. It is all here. This is Darwin coming to an understanding of the Big Picture of Evolution.

At Punta Alta, a low cliff, about twenty feet high, exposes a mass of [sediment] containing numerous recent shells. We may believe a similar accumulation would now take place … where tides and waves were opposed. In the gravel a considerable number of bones were embedded. … the following list may give some idea of their nature: 1st, a tolerably perfect head of a megatherium, and a fragment and teeth of two others; 2d, an animal of the order Edentata, as large as a pony, and with great scratching claws; 3d and 4th, two great Edentata related to the megatherium, and both fully as large as an ox or horse; 5th, another equally large animal, closely allied or perhaps identical with the Toxodon …, which had very flat grinding teeth, somewhat resembling those of a rodent; 6th, a large piece of the tesselated covering like that of the armadillo, but of gigantic size; 7th, a tusk which in its prismatic form, and in the disposition of the enamel, closely resembles that of the African boar; it is probable that it belonged to the same animal with the singular flat grinders. Lastly, a tooth in the same state of decay with the others: … but the part that is perfect, resembles in every respect the tooth of the common horse.* … the space in which they were collected could not have exceeded one hundred and fifty yards square. It is a remarkable circumstance that so many different species should be found together; and it proves how numerous in kind the ancient inhabitants of this country must have been.

… in another cliff of red earth, I found several fragments of bones. Among them were the teeth of a rodent, much narrower, but even larger than those of the Hydrochærus capybara; the animal which has been mentioned as exceeding in dimensions every existing member of its order. There was also part of the head of a Ctenomys; the species being different from the Tucutuco, but with a close general resemblance.

The remains … were associated … with shells of existing species. … similar to the species now living in the same bay: it is also very remarkable, that not only the species, but the proportional numbers of each kind, are nearly the same [as the modern fauna] … If I had not collected living specimens from the same bay, some of the fossils would have been thought extinct … We may feel certain that the bones have not been washed out of an older formation, and embedded in a more recent one, because the remains of one of the Edentata were lying in their proper relative position (and partly so in a second case) …

…

From the shells being littoral species … we may feel absolutely certain that the remains were embedded in a shallow sea, not far from the coast. From the position of the skeleton being undisturbed, and likewise from the fact that full-grown serpulæ were attached to some of the bones, we know that the mass could not have been accumulated on the beach itself. …

From the general structure of the coast of this part of South America, we are compelled to believe, that the changes of [elevation] have … of late … been in one direction, and … very gradual. If, then, we look back to the period when these quadrupeds lived, the land probably stood at a level, less elevated only by a few fathoms than at present. Therefore, its general configuration since that epoch cannot have been greatly modified; …

The surrounding country, as may have been gathered from this journal, is of a very desert character. … Here, then, is an apparent difficulty: we have the strongest evidence that there has occurred no great physical change to modify the features of the country, yet in former days, numerous large animals were supported on the plains now covered by a thin and scanty vegetation.

That large animals require a luxuriant vegetation, has been a general assumption, which has passed from one work to another. I do not hesitate, however, to say that it is completely false; and that it has vitiated the reasoning of geologists, on some points of great interest in the ancient history of the world. The prejudice has probably been derived from India, and the Indian islands, where troops of elephants, noble forests, and impenetrable jungles, are associated together in every account. If, on the other hand, we refer to any work of travels through the southern parts of Africa, we shall find allusions in almost every page either to the desert character of the country, or to the numbers of large animals inhabiting it. The same thing is rendered evident by the many sketches which have been published of various parts of the interior. When the Beagle was at Cape Town, I rode a few leagues into the country, which at least was sufficient to render that which I had read more fully intelligible.