Broadly, there are two kinds of published paper: review papers, which summarise and synthesise existing knowledge; and research papers, which add something new. (For an example of the former, see my paper Sauropod dinosaur research: a historical review at … istory.pdf and for an example of the latter, the zippily named A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA at … 100073.pdf )

You can certainly write a research paper based on your own blog-posts: the fact that original research is original research isn't negated by its having appeared on blogs before. As an example, yet another of my own papers, Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications at … -10-11.pdf was adapted directly from a series of eight blog-posts linked from … furcation/

Do you need to handle a fossil yourself to write a paper about it? It depends. If it's a purely descriptive paper, as in our description of the awesome sauropod Brontomerus linked above, absolutely yes. Even 3d models are no substitute for the real fossil. But if you're advancing a palaeobiological hypothesis, as in the Smilodon blog-posts, then no. Your research is not about the fossils per se, but about the animals and how they lived. For that, you can rely on previously published descriptive work and photos.

What you propose is possible -- we see it in some other animals, for example in the many spider species where males are much smaller than females -- but I know of no evidence for it. But in this case, lack of evidence doesn't tell us much anyway -- we have so few well-sampled sauropod species that almost nothing can be said about how populations varied.

I think you must have misread whatever it was what Ken said: bone strength would not be the limiting factor, and he would know that. Muscle and cartilage both become issues before bone.

David, I can never get this straight in my head:

"Genetically there is no evidence for human races."

But then:

"The differences in facial and body features we see are caused by subtle differences in gene expression between populations, caused by minor differences (SNPs) in the promoters, regulatory and coding regions of genes. These differences have been selected for over thousands of years to allow adaptation to local differing conditions."

That sounds like you're saying there is a genetic cause for the differences we see between different populations. And indeed I can hardly see how it could be otherwise. What is the story here?

"If the Earth was millions of years old, we would be dying of thirst, or freezing to death."

No. The Earth recycles water -- everything ingested is eventually removed from the body as urine, sweat or some other kind of moisture.

And the Earth is more or less in thermal equilibrium -- the amount of heat is radiates away is about the same as what it receives from the Sun. Obviously there are fluctuations, but overall this holds.

And a great find, too!

(posted in Evolution)

Note though that some other animals have functional cervical ribs, including birds and crocs. Dinosaurs had them, and in particular some sauropods had immensely long cervical ribs. A single cervical rib of Mamenchisaurus sinocanadorum measures over 4 m in length!

BTW., the synsacrum is the hip region: all the verterbrae in that region fuse together, and the hip bones fuse to those, yielding the single object you found. Mistaking them for skulls is very common -- my wife made the same mistake just the other day.

In ecological terms, Sarchosuchus likely functioned very much like a modern crocodile or alligator: lurking in water, grabbing anything unwary, and drowning it or simply tearing it apart. For a croc of that size, the idea that they would not take dinosaurs stretches credibility. Why would they pass up a perfectly good meal?

This is not the advice you want, but here it is anyway ...

Communication is always important, in almost any job. There may be nothing you can do about your stutter (although some forms of therapy can be helpful). But you can work on your written communication.

Your question is full of typos, misspellings, incorrect punctuation and lower-case letters where capitals are required. You can learn to fix all these problems, if you'll take a little more care. Doing this will make you a much more appealing candidate for any job.

Not really what you asked, but I hope it's helpful. Perhaps others will have ideas about specific jobs.

(posted in Fossils)

Then I think all we can say about this is: [citation needed]


Speaking as another member of the palaeontological community: what Dave said.

(posted in Fossils)

I have no idea how you would postulate such a thing. Do you have a reference?

(posted in Fossils)

Much less than 1% of the Earth's surface has been excavated; but fossil deposits cover much more than 1% of the Earth's surface. There just isn't the manpower to excavate all of it (plus much of it is inconveniently covered with forests, cities, etc.)

The same reason explains the number of fossils that have been found -- a number that you seem to think is small). For most of the 4-7 thousand years of modern civilisation, no-one was collecting fossils. For most of the last few hundred years, only a couple of hundred people have been collecting them. It's only in the last few decades that that has really changed -- and, sure enough, the rate of fossil discovery has gone through the roof.

Au contraire, David -- among scientists who study long-necked creatures such as my own sauropods, the RLN is of great interest. Matt Wedel (my co-blogger over at Sauropod Vertebra Picture of the Week) wrote a paper on the RLNs of sauropod a couple of years ago. See his very readable layman's version at … sauropods/

The real question is whether there is life anywhere else in the universe. (As someone has pointed out, but annoyingly I can't remember who, the great thing about that question is that either answer, "yes" or "no", is astounding.)

If there is life, and it has evolved complexity and intelligence, then it doesn't seem particularly unlikely that it's evolved a shape very broadly similar to ours: limbs for locomotion and more limbs for manipulation. Of course they might be built more like centaurs than humans. Or they might be more like an octopus. (Octopuses might be the best bet for intelligence evolving on Earth, if all the vertebrates were to suddenly disappear.)

Hi, George. It depends on what you mean by "toes". The front feet had all five digits, but really only as far down as the metacarpals. In humans, those are the bones that run through the palm of your hand, connection the wrist to the fingers proper. But in sauropods, these bones formed a vertical tube that effectively was the forefoot. You can see those of Giraffatitan in this picture: … jango.jpeg

As you can see, there is one manual phalanx on the end of each metacarpal -- the small bones at the bottom of the forefeet -- but in life these would all have been encased in a tube of flesh. The only distinctive feature of the forefoot of Giraffatitan (as with most sauropods) would have been the single, rather small, claw on the thumb.

The hindfeet are rather different, as you can see in this phooto:

They had five more fuinctional digits, somewhat spread out across the ground -- but they too would have been encased in a pad of muscle, gristle and skin, like the feet of elephants. Only the three inner toes would have been visible in life, as they bore claws.

So the answer to your question is either "five fingers and five toes" or "one thumb and three toes", depending on whether you're talking about the skeleton or the life appearance.

By the way, in the background of that second photo, and facing towards us, is a smaller sauropod, Dicraeosaurus. You can see its thumb claws really clearly from this angle.

These specimens are in the main hall of the Museum fur Naturkunde Berlin. If you can get over there some time (and there are good cheap flights available from the UK), I simply can't recommend it highly enough. It's my favourite room in the whole world.

If vertebrates can evolve flight, why are all vertebrates not flying?

Same question. Just because an organism has the potential to evolve in a certain way doesn't mean that it will: it will evolve in response to the specific pressures exerted by its environment. For many unicellular eukaryotes, their present form is nicely optimised for their evironment, and there would be no benefit to multicellularity.

Because David is a medical doctor, he has to be more careful than the rest of us about being very clear that he is not giving medical advice.

As a palaeontologist, though, I am less constrained, so let me say it clearly: get your kids immunised. Not to do so would be dangerous and irresponsible, not only towards your own children but also towards the broader community. Anti-vaxers are conspiracy nuts of the worst kind. Please ignore them, and instead go along with the literally universal advice of trained medical professionals.

There is nothing especially wonderful about having four limbs, as any snake, insect, spider or millipede will tell you! The fact that so many of our Earth creatures to have four limbs is that so many of us are tetrapods: we inherited the four-limbed condition from a distant ancestor. Some have modified this either by standing upright (humans, kangaroos), changing one pair of limbs into wings (birds, bats) or losing them altogether (snakes, amphisbaenians), but all amphibians, reptiles, birds and mammals started out from a four limbed ancestor.

(If you've seen Avatar you'll remember that most of the wildlife on Pandora has six limbs. That's probably just as good an arrangement -- again, the wild success of insects suggests that it is.)

THat makes sense -- although note that what you're describing is not progress in human evolution, which is to do with changes to genome inherited down the generations, but progress in human culture.

As it happens, I have only one kidney -- it's a congenital defect, not the result of an accident. What's happened is, the other kidney has taken up the slack. It's somewhat bigger than normal, and doing just fine. I call it my superkidney.

The horns of ceratopsians had bony cores -- those are the parts that fossilise -- with a keratin sheath. In that way, they're much like the claws of birds and other animals. In life, ceratopsian horns would have been somewhat longer, thicker and sharper than the fossils alone suggest.

It's actually not a resolved question what ceratopsians used their horns and frills for. We can be pretty sure that they were multi-purpose structures (as nearly all structures are), and that the emphasis in how they were used was different in different species, just as different antelopes use their horns differently.

But you're right that present palaeontological opinion leans towards the idea that the frills and horns were primarily display structures. That said: there is good evidence that they were also used, at least in Triceratops, for interspecific fighting -- establishing dominance over territory or mating partners. And there's this: if I were a Triceratops and I encountered a tyrannosaur, I would not stop and think to myself "Hang on, my horns and frill are primarily display structures", I would do my best to impale that bad boy before he killed me.

The page you linked has many photos and I don't know which one you mean. But I would be astonished if pterosaurs didn't sometimes rear bipedally for threat displays: bears, gorillas and many other animals do it.

A shark is one of the things this can't be, since it's a bone. Sharks (and their relatives, the rays) have soft skeletons made from cartilage instead of bone. So this is almost certainly a vertebra of some other big fish. (Don't forget that sharks are fish, too!)

Close elephant relatives like the extinct mammoths and mastodons belong to the group Proboscidea (which basically means "nose-havers", in reference to the trunk).

This group is contained within the wider group Afrotheria --see -- a group with surprising contents including elephant shrews, aarvarks and (among the groups most closely related to elephants) manatees!

David, I think that B. D. Shenoy is referring more generally to fungi associated with palms on sandy beaches. Do they need to be salt-tolerant to flourish in that environment?

I don't know the answer to the specific question you asked, but one other thing you need to know for your novel: the density of alcohol (ethanol) is much less than that of water -- only 789 kg/m³ -- so there is no way a human could swim in it. Your protagonists will sink straight to the bottom, and so they will drown if they're in there for long -- some time before alcohol poisoning has time to take effect.

Otherwise, the question comes down to the extent to which ethanol can be absorbed be the skin (as opposed to the stomach, as when we drink it). That I don't know.

This page has a good summary of where we're at:

That depends on how old you are, and how much you already know.

I'd recommend these three, to be read in this order. Excuse the dinosaur bias, as that's what I study myself.

1. The Dinosaur Heresies, by Bob Bakker. Written in 1986, this book was at odds with what was then orthodox, but in many respects its ideas have been vindicated by subsequent work. Its age shows, and much of the detail is no longer useful, but it's still the best book I know as an introduction to the excitement of how palaeontology is actually done.

2. Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, by Tom Holtz. Amazingly cheap, very complete, pretty well up to date (it's from 2007), and scientifically impeccable.

3. The Dinosauria, 2nd edition, edited by Weishampel et al. Absolutely hardcore, and definitive about every single dinosaur group. Take a look before buying, though, it's fearsomely technical and will be offputting if you're not ready yet.

That looks like an ulna (the bone of the upper fore-limb) -- or possibly a tibia to me (the main bone of the lower hind-limb). Either way, four inches in length is much too small for it to be human.

Sorry I can't be more specific; others may be able to contribute more.

(posted in Mammals)

Sorry, but there is no way to answer this with any confidence. You're asking how an animal will react to a sudden change in its own size -- something that never happens in real life, and so simply can't be analysed.

What we can say is that a house-cat the size of a lion would not be very well engineered: lions are proportionally more robust than house-cats, as they need to be to function with similar athleticism.

Life is not like Dungeons and Dragons! There are no pre-determined rules that say what combination of character-classes or special powers are possible. Organisms will evolve the sybioses, parasitisms and mutual relationships that best propagate their genes, whether that means zero, one or many such relationships.

(posted in Evolution)

Evolution is backed up by the fossil record, by studies of populations in the wild, and by laboratory studies of populations of bacteria. The evidence is overwhelming, and simply not in dispute within the scientific community.

But: speaking as a Christian myself, I would not attempt to "disprove Biblical study". What I do instead is to recognise what kind of a thing the Bible is and is not, and specifically that it was never intended as (nor until relatively recently read as) a science textbook. The nature of the language that it uses simply doesn't admit that interpretation. In the 139th Psalm, David writes "I was woven together in the depths of the earth". But no-one interprets that as a scientific claim about where babies come from. In the same way, it simply makes no sense to interpret the opening chapters of Genesis as a scientific claim about the origin of diversity of life.

If those chapters mean anything (and although I believe they do, I recognise that others disagree), then they about the nature of God, the nature of humanity, and the relationship between them. That has literally nothing to do with evolution.

I've not seen that show, but I can tell you that there are very solid restrictions on how strong a human can be -- limitations imposed by the properties of bone, cartilage and muscle. Although there is a little variation in muscle between individuals, and between species, all muscle fibre is capable of exerting pretty much the same stress. That means that the strength of a muscle is almost exactly proportional its cross-sectional area, and that is of course limited by the structure of the human body. So you could never have, for example, Captain America lifting a car above his head: there necessary amount of muscle simply won't fit on a human.

As far as we know, diplodocids -- like all other amniotes -- habitually held their necks elevated. See … e-rabbits/

So: browsing, the same as brachiosaurs, and all other sauropods. No doubt some also used those necks for other purpose -- for example, apatosaurs may have used theirs in intraspecific combat -- but they were primarily about getting as much food as possible, as quickly as possible.

Different sauropods would have reared with different levels of expertise. Diplodocids were probably very good at it, as their centre of mass was already close to the hips. Brachiosaurs would have done less well, and probably avoided rearing except when absolutely necessary.

No, the Earth's gravity has been unchanged, within very tight parameters, since long before the age of the dinosaurs. Other factors, such as sea level, proportion of atmospheric oxygen and average temparature, have changed much, much more during that time.

But the large size of dinosaurs was not due to any of these factors (otherwise they would not have continued to evolve very large species all through the Mesozoic, as those factors changed). Neither was it due to cool-bloodedness, which in fact prevents large body size and it's simply not possible to grow fast enough to get really big without a high metabolic rate.

The dinosaurs were fundamentally better than us (i.e. mammals) at growing big. There are quite a few reasons but among them is this: the sauropods (biggest of all) didn't waste time chewing food as mammals do. They just cropped and swallowed. This allowed them to ingest much more quickly.

I don't know about the caudal neural spines. In general, it seems that different species often have differences in their bones that are without any obvious reason based on lifestyle. These can be the result of genetic drift -- i.e. they are selectively neutral. Or they could be affected by the same genes that are being positively selected for other reasons: most genes do more than one thing.

Fusion of the scapular and coracoid is common in fully mature dinosaurs, but many individuals that we think of as mature (e.g. the huge brachiosaur in the atrium of the Museum Für Naturkunde Berlin) are actually not skeletally mature. So we're used to see unfused scapulocoracoids. My best guess is just  that the Majungasaurus skeleton that reconstruction is based on happened to be fully mature.

I wouldn't rule out a semi-aquatic lifestyle, but you'd need more to go on that just a vague, general sense of body shape.

I think this could well be a fossil, though I don't know what of. (Some kind of invertebrate, I imagine, and I specialise in dinosaurs so it's a bit out of my zone!)

This is worth taking along to your local museum, and asking them to look at it in person.

Sorry, slow to the party here. Yes, rhynchocephalians including the extant tuatara are diapsids. Specifically, they are lepidosaurs, which means they are closely related to lizards and snakes -- more closely than to crocs or turtles.

Almost certainly. Coelophysis is pretty primitive within the theropod tree. It's most parsimonious to assume that it and birds inherited their furculae from their most recent common ancestor, and it's unlikely that that common ancestor was the first theropod to have a furcula.

The problem of course is that the bone is  small, fragile, easily lost from a carcass and easily overlooked by field crews. It's not known from many theropods, but it's likely it was there in all or them (unless secondarily lost in some lineages).

(posted in Fossils)

I'm afraid this doesn't look like a fossil to me. I'm afraid what you have here is the process of a geological process, not a biological one. That said, it's an interesting shape -- perhaps the result of lava cooling or something similar?

Your question is right in principle -- yes, we do say that birds are reptiles. But none of the ancestor groups of mammals are descended from reptiles. The broader clade that includes mammals is Synapsida, which includes the pelycosaurs -- but Synapsida is the sister clade to Sauropsida, the great clade that contains all reptiles, including dinosaurs and birds. (These are the two branches of Amniota, the clade that unites reptiles and mammals to the exclusion of amphibians).

The situation is made more complex for two reasons. First, basal synapsids, including pelycosaurs, used be known informally as "mammal-like reptiles". This was never correct; "reptile-like mammal" would have been a better term.

Second, the most primite amniotes -- whether in the synapsid or sauropsid or branch -- looked superficially like lizards. So it's easy to see why someone would informally talk about mammals having evolved from "reptiles", meaning the lizard-like animals at the base of Synapsida. But that's not really right: only animals on the sauropsid branch are technically reptiles.

Huh. I routinely drink month-old bottles of tapwater that have been sitting in the car. I guess I should get in the habit of refreshing it.

Only one week? Ouch. What happens after that time, then?

(posted in Fossils)

Yes. For example, early amniotes have features linking modern mammals and reptiles.

The most primitive form of these organs would have been tubes allowing bodily fluids to disperse through the body; then a form that use peristalsis (local contractions) to move the fluids more efficiently; then a more complex network of tubes; then an increasingly specialised a powerful perstaltic region that eventually evolved into a heart. Each step has survival/reproductive value on its own.

I imagine the issue here is taxon selection in the specific analysis you mention. I'll leave it to a theropod specialist to comment further.

"The reasons I have asked this, is because the dinosaur to bird theory has many state transitions, lengthy ghost lineages and numerous exaptations."

No it doesn't. Cladistic analysis that include modern birds and mesozoic theropods include big transitions, because of the big chronological gap. But analyses that include a good selection of ancient and modern birds as well as anceint theropods have nice, clean transitions of only a few characters each. The difficulty is drawing a line at any point and saying "the animals more derived that this, we will count as birds". There's no obvious place on the tree to do this, precisely because the transition is so smooth.

(posted in Mammals)

Yes, this is a rodent incisor; and from the size, I think a beaver would be a likely source. Its not overgrown: amazing as it seems, this is normal for a rodent incisor, which continue to grow throughout life and always have a large uneruped portion embedded in the jawbone. For a graphic example, see Squirrel incisors are insanely huge at … nely-huge/

I have a (cast of) a T. rex tooth on the shelf right in front of me as a type this. The crown (the part of the tooth that would have been visible, projecting above the gum) is about 15 cm (6 inches) long. The root is truncated in my cast, but probably would have been about the same length, making the whole tooth about a foot long.

Not all the teeth of this individual would have been the same size or shape. In general, the teeth a relatively small right at the front of the mouth, then larger, then become progressively smaller towards the back. But there are lots of exceptions to this general trend, dependent on how old each individual tooth is. (Teeth were replaced continuously throughout life, so a big tooth could be pushed out by an initially small replacement.)

They're not all the same shape either. The front teeth are D-shaped in cross-section, while further back the cross-section is more like a rounded diamond.

And most important: tyrannosaurs did not have sharp teeth! The common description of them as "like steak knives" is completely wrong: they were more like rock-solid bananas. Why? Because they optimised for crushing rather than for slicing. Tyrannosaur teeth are hammers, not knives.