I'm bored, and randman insulted my skills in the area, so I'm going to look more closely at his "aquatic lizards evolved into whales" link.
link said:
The word whale, in biological discussion, refers not only to the large marine mammals commonly designated by that name, but also to other, smaller members of the order Cetacea such as dolphins, porpoises, belugas, and narwhals. In the discussion that follows, whales is used in this broader sense.
This is a bad sign right from the start: they don't go into ANY depth in terms of taxonomy. They redefine a common name, when in fact they wish to talk about a specific, and named, clade. It suggests--it doesn't prove, but it strongly suggests--that they haven't done their due diligence. No, to be fair, scientists often use common names. However, not when they're dealing with the intricacies of taxonomy. Later on say whales--here you need to show the specific taxa you're talking about, who named what, and why.
The accepted account of the evolution of whales is poorly documented in terms of fossils. Relatively few marine fossils of any kind are known from the Paleocene, the first epoch of the Cenozoic Era, the so-called Age of Mammals.
This one just made my head spin. It's a complete non-sequitor. Sure, there may be valid reasons for discussing the Paleocene in an article about Cetacean evolution--but the authors don't give us any. And this is a serious problem. There's simply not that much rock exposed from the Paleocene (compared to other periods), which means that we're naturally not going to find much there. Worse, it's a recovery fauna, one of two classic recovery faunas (the other being the Early Triassic). Pointing out that there's not many fossils from any but a handful of invertebrate taxa is akin to say "There's not much left after a forest fire".
The earliest fossil forms normally classified as whales date from the ensuing epoch, the Eocene (~54–34 mya).1
Okay....The author is trying to suggest that we need to explain an ecological vacuum. "There wasn't enough food in the sea during the recovery from the K/Pg event to sustain large predators, much less warm-blooded ones." Done.
Oh wait, it keeps going...
The usual story about the evolution of whales says that they, and all the other placental mammals (as has already been explained, evolved from a "small, primitive, generalized" terrestrial placental mammal living in the late Cretaceous Period (approx. 70 mya). Many even take it for granted that whale ancestors first evolved into ungulates and only later became whales.
Let's leave aside the VERY casual language here (it's another bad sign" and go with the meat: The author is dismissing the commonly accepted view. There's one citation here--ONE--and the rest is mere hand-waving.
The creatures usually proposed as whale precursors are the mesonychid ungulates of the middle and lower Paleocene. But writers who assert this radical transformation actually occurred rarely mention that late Paleocene fossils documenting the transition between mesonychids and the earliest recognized whales are entirely lacking.3
The highlighted part is pure sensationalism which has no place in science. Leaving that aside, this is the old "There are no transitional fossils" argument.
Robert L. Carroll said:
It is not possible to identify a sequence of mesonychids leading directly to whales, although some teeth now recognized as belonging to primitive whales were originally described as from mesonychids. All adequately known mesonychids were terrestrial in most aspects of the skeleton, and some show specializations for cursorial [i.e., running] locomotion.
Interesting note:
Wiki said:
Robert Lynn Carroll (born May 5, 1938, Kalamazoo, Michigan) is a vertebrate paleontologist who specialises in Paleozoic and Mesozoic amphibians and reptiles.[1]
So this guy isn't exactly an expert. Probably still good, but he's a bit out of his field. And the (undoubtably cherry-picked) quote doesn't even say what the author of randman's article thinks it says. What this is saying is that there's a gap, yes--but then he give evidence that the gap isn't really that big. There's clear morphological similarities between cetaceans and mesonychids. This isn't uncommon in the fossil record--we can only work with the rock we have, and the stratigraphic record is more akin to a tree after it's gone through a wood chipper than it is to a layercake.
Then the author flagrantly insults the status quo:
If you think in terms of divergence and phylogenies, you
cannot hope to fully understand the comments concerning
the evolution of whales on this page, nor the arguments
concerning the Mesozoic origins of mammals on the other
pages of this section.
Enough said.
But an examination of the currently accepted reconstruction of Pakicetus (Figure 9.3) will convince most readers that Pakicetus, as a whole, is more like a dog than a whale.
This is an appeal to the average man. The problem is, taxonomists aren't the average man--they're experts.
On the same web page,4 maintained by the laboratory of Hans Thewissen, a widely recognized authority on early fossil cetaceans, where Figure 9.3 originally appeared, another illustration shows the skulls of two pakicetids (Ichthyolestes and Pakicetus) are comparable to that of a modern coyote (Canis latrans). Saying that the evolution of whales started with this doglike animal is sheer nonsense when fossils that long predate it are actually very similar to whales (see figures 9.4 and 9.5 below).
This one just hurts. Hans Thewissen is discussing functional morphology in comparing the skulls of those pakicetids, NOT taxonomy. Those are two very different fields. In functional morphology you find whatever you can that looks like the thing you're looking at, and you compare the way they move and what the thing that has the structure does with it. I forget the taxa off-hand, but I remember reading a paper where grad students welded steel cones with holes drilled into them together to simulate how a certain organism looks in the fossil record, and found out that this created a vortex which they hypothesized the animal used to feed. Does that mean that this animal is related to sheets of steel with holes drilled in them?! This type of cherry-picking only comes from an agenda.
But those who make such claims also embrace the notion that whales (and all other placental mammals) evolved from a tiny late Cretaceous shrewlike insectivore. They fail to mention, or perhaps do not realize, that whalelike, whale-sized creatures existed already in the Cretaceous, prior to the Paleocene.5
More insults. I have yet to meet a paleontologist that wasn't aware of the Mesozoic megafauna. I've talked with experts on the Vendian fauna who knew about marine Mesozoic megafauna, and you can't get much further apart than that.
The teeth of Mosasaurus hoffmanni, as pictured by Lingham-Soliar (1995: 160) are quite similar to those of late Miocene Zygophyseter varolai, an early sperm whale (Bianucci and Landini 2006). The teeth of mosasaurs such as Mosasaurus8 and Hainosaurus9 are similar, also, in both size, and in crown and root morphology, to those of large, living toothed whales, such as those of Orcinus, Physeter, and Pseudorca (Hillson 2005: 72, fig. 1.47).10,11
The teeth of ceritopsian dinosaurs were similar to those of mammoths. That's not because ceritopsian dinosaurs evolved into mammoths--it's because they ate the same food. Same with some of the pterosaurs and some predatory fish. This is a functional constriction: If you eat certain foods, you require certain teeth. If you do not have them, or have tools to compensate, you starve. Pretty strong selection pressure, that.
The backbone thing has the same explanation.
Like modern whales, mosasaurs were deep divers — their remains show signs of avascular necrosis (Rothschild and Martin 1988, Martin and Rothschild 2005; Martin and Rothschild 1989), a condition resulting when nitrogen forms bubbles in body tissues after a dive. A recent study has shown deep-diving sperm whales are also affected by this condition (Moore and Early 2004). Moreover, the remains of giant squid, prey taken by large extant toothed whales during deep dives, have been found in the gut contents of ancient mosasaurs (Martin and Rothschild 2005: 343).
Similar ecological niche. Cool. Not surprising.
But it should be mentioned that, even earlier, a widely respected comparative anatomist asserted that mosasaurs were whales.
The age of an idea has no bearing on the accuracy. In fact, if anything it's a mark AGAINST the accuracy of a scientific idea. How much evidence have we found to date that contradicts it?
The first mosasaur jaws were found in 1766 in St. Pieter's Mountain in the Dutch city of Maastricht.14 But a second specimen, a huge partial skull discovered nearby in 1780, received far more attention.
Two partial skulls. THAT was his sample size. Back before we knew enough about dinosaur anatomy to put them in the right positions. Sorry, not convincing.
Camper pointed out that the teeth of the unknown animal were embedded in deep sockets within the bone of the jaw, a fact confirmed by modern investigators (Lingham-Soliar 1995: 169). Such a condition is characteristic of neither snakes nor of varanid lizards (King and Green 1998). Indeed, such ("thecodont") teeth are generally characteristic of mammals (Smith 1958: 223).15
This is just FLAGRANT misdirection. Thecodont teeth are a characteristic of an entire group of organisms, of which mammals make a part. Therapod dinosaurs, for example, all have tehcodont teeth. Something like 2/3 of a T. rex tooth is under the gum line. I doubt that the author is unaware of this--it's hard to be--so I can only assume that they don't want the reader to remember that reptiles do, in fact, show thecodont teeth.
In particular, the form of the Maastricht animal's teeth, as Camper pointed out, and has already been mentioned, are like those of large extant toothed whales.
They're also remarkably similar to therapod dinosaur teeth, suggesting that it's a diet thing, and not, as the author suggests, a shared derived trait.
I strongly suggest that anyone interested in learning more about the role of teeth in evolution look into horse teeth. There's something of a debate in paleontology right now about how effective dental morphology is in tracing lineages. At the very least, the dishonesty shown in this article should cause the reader to seriously question the validity of these conclusions.
Cuvier, who originated the idea that the Mesozoic was dominated by reptiles, readily embraced the idea that mosasaurs were huge lizards (though mosasaur fossils are always found in association with fossils of known marine origin).
First, most of the fossil record is marine. I first went away from vertebrate paleontology because of that fact. Second, marine reptiles are not unknown, and flying reptiles such as pteranodons ARE today. The aside here, slipped in to prevent anyone from questioning it, is implying something that's contrary to all the available evidence. Also, there's the pleseosaurs and ictheosaurs to deal with. These are obviously lizards--and they're marine.
With the weight of his great reputation, he established the younger Camper's theory as one of the standard hypotheses usually considered in discussions of mosasaur origins.16
Nice implication here: the big, powerful establishment is suppressing the truth! Only, they forgot that geology back then was hardly the calm, civilized dicipline we have now (remember my comment about explosives and fist-fights when you read that). This was back when geology was just starting--there were several competing theories floating around for just about everything, with ardent supporters on all sides. You couldn't simply railroad something into orthodoxy--there WAS NO orthodoxy!
However, a glance at figures 9.4 and 9.5, will convince most readers that mosasaurs have much in common with early whales.
Two problems here. First, again, the "average man" is not who this article should be trying to convince. They should be talking to experts. Second, those pictures are no where NEAR clear enough to show, well, anything in morphology. Fossil photography is hard, and line diagrams are even more tricky. You pick the scale to show what you want to show. A scale that size is showing gross morphology--meaning FUNCTIONAL morphology. Just about the only thing you can see in 9.4 and 9.5 is that it's a vertebrate and the arangement of the limbs. This isn't nearly enough. I've got a book with two pages on the knuckle bones of each taxa in the book, each bone drawn bigger than the critters in those figures.
As for the in-depth analysis of the skull, we get this:
Note that the while the
nasal openings are in approximately the same position in both skulls,
there is a single, fused opening in the more recent Dorudon.
The nostrils are in a similar place. What about those holes in the skull of the one on the left? You know, those holes that are distinctly reptilian? Postorbital fenestras, I believe they're called (not up on my Cretaceous herpetology). To focus on the nose, which is pretty mobile, and ignore something as major as holes in the skull, is rediculous.
Lingham-Soliar (1995: 178) says the disappearance of mosasaurs at the end of the Cretaceous "is an enigma," "sudden and unexpected."
I strongly suspect more quote mining. I have little doubt that later in the paragraph this author goes into the various causes of extinction. So, dishonesty. Again.
There is only another case of the now familiar tendency (we have seen repeated examples in the previous pages of this section) of paleontologists to identify as reptiles forms of Mesozoic age — even when those forms are highly similar to younger forms known to be mammals
A tendency. This implies that this is something paleontologists take lightly. Which is, frankly, deeply insulting. Paleontologists don't just throw out theories, and we certainly don't throw out whatever taxonomic affinities come to mind! Taxa have definitions, particularly before the rise of phylogeny and cladistics. If the thing didn't fit the definition, it didn't go into the taxa. Grab a copy of The Treatise on Invertebrate Paleontology sometime--every volume, every FAMILY (it only goes down to genus) practically, has a clade labeled "Problematica" or the like--a place to put things which fit the definition of the higher clade, but don't fit anywhere else (and usually exhibit some other problematic trait--it's more than just "Oh, it's a new subclade).
And this is a SERIOUS flaw in this article: the author never gives his criteria for evaluating the taxonomic affinities of these animals. The author simply points out a few superficial similarities, says that some dead scientist once said something that sounds like what the author is saying, and leaves it at that. To put it bluntly, this article is too easy to read.
Here's what a good taxonomic description should sound like:
The Dinosauria said:
The sauropod manus displays a trend towards phalangeal reduction. The manual phalangeal formula is 2-2-2-2-1 in basal forms such as Shunosaurus and 2-1-1-1-1 in many neosuaropods, such as Apatosaurus and Camarasaurus, and there is some indication that titanosaruians lacked any phalanges whatsoever (SAlgado et al. 1997a).
The paragraph goes downhill, in terms of keeping the reader's attention, from there. The author of the article randman linked to does not, fundamentally give a taxonomic description--they merely gloss over the morphology with generic terms, and move on to the sexy part of the paper, the conclusions (in fact, that's another flaw: The author can't help mixing the conclusions with the data).
So yeah, it wasn't a hard article to read. Wasn't hard to comprehend. The author doesn't provide adequate support for anything they say, and draws a conclusion by ignoring glaringly obvious morphological facts, all the while slipping in their conclusion as if it were already accepted and insulting those who disagree. This wouldn't get published in the most disreputable scientific journal.
All in all, I can see why randman likes it.
