I read a lot of books in 2010, and mostly enjoyed all of them. Among my favourites was Luis Chiappe's Glorified Dinosaurs: The Origin and Early Evolution of Birds, and in the lengthy review article below (currently in press for Historical Biology) you can find what I thought of it. Note that Glorified Dinosaurs is not especially new (it appeared in 2007): it typically takes a few years for lengthy written reviews of large books to see completion (or, ha, it does in my case anyway).
One more thing to note: some of what I say here (e.g., about the relationship between birds and other dinosaurs, about Alan Feduccia [et al.'s] claims, and about the strong morphological similarity between deinonychosaur-like birds and bird-like deinonychosaurs) will make familiar reading if you've read any of my stuff before (especially my review of Gary Kaiser's The Inner Bird). Sorry about that, but the same points had to be made.
Glorified Dinosaurs: The Origin and Early Evolution of Birds, by Luis M. Chiappe, John Wiley and Sons, 2007, x + 263 pp., ISBN 0-471-24723-5
For all their current popularity as objects of research interest, fossil birds remain chronically under-represented in the popular literature. Only one book aims to cover all of avian palaeontology: Alan Feduccia's The Origin and Evolution of Birds (1996, and republished 1999; itself an expanded version of Feduccia's 1980 The Age of Birds [images of both books shown below]). However, Feduccia's views on such topics as avian origins, the phylogeny and biology of Mesozoic birds, and the affinities of the major modern bird groups are idiosyncratic and do not accurately represent the status of palaeornithological knowledge. A significant gap in the market therefore remains. Until now perhaps, for Luis Chiappe's new book - Glorified Dinosaurs: The Origin and Early Evolution of Birds - fills that gap for Mesozoic birds, at least. As I hope to show here, the book is beautiful, superbly written, authoritative and comprehensive.
Two things are emphasised from the beginning: a strong reliance on cladistics, and the dinosaurian origin of birds [Deinonychus shown here; by Arthur Weasley, from wikipedia. Like it or not, Deinonychus really did look like a giant, flightless Archaeopteryx]. Chiappe spends considerable time (103 of the book's 263 pages) covering these subjects. Keen to get to the book's extensive coverage of Mesozoic birds, I found the discussion of geological time, reptile evolution, and non-avialian dinosaur diversity over-long and unnecessary. Authors of palaeontological texts do of course have to set the main focus of their attention within the broader context of geological and evolutionary history, but if you've read a lot of popular texts on vertebrate evolution you end up feeling that you've heard the same story all too many times before.
As Chiappe shows, the evidence linking birds to other maniraptoran theropods is outstandingly good. He uses many of the recently discovered Cretaceous fossils from Liaoning Province and Mongolia to show how features once thought unique to birds all evolved earlier on in other maniraptorans. These features include morphological attributes such as complex feathers, a particular type of wrist folding, and distinctive eggshell microstructure, as well as aspects of brooding behaviour and the habit of laying egg clutches over many days.
The best evidence supporting the theropod origin of birds remains the detailed anatomy of maniraptorans and other coelurosaurs, and since the 1990s our knowledge and appreciation of coelurosaur anatomy has increased exponentially. New specimens of long-known taxa like Velociraptor have been described in detail, but we also have such new fossils as the oviraptorosaurs Caudipteryx, Protarchaeopteryx and Citipati, the troodontid Mei, and the dromaeosaurids Sinornithosaurus [the sinornithosaur NGMC 91 shown here] and Microraptor. Non-maniraptoran coelurosaurs like Sinosauropteryx and Dilong have shown that a simple, filamentous integument appeared before true feathers did, therefore providing fossil support for the model of feather origins proposed by Prum (1999). This discovery adds to the evidence indicating that feathers did not evolve from scales, but rather represent evolutionary novelties (Brush 1996).
An origin of birds from within coelurosaurian theropods would seem to suggest that bird flight originated on the ground, rather than among the trees. But the possibility that such maniraptorans as small dromaeosaurids and early birds were capable of at least some climbing still appears reasonable to some workers. Chiappe is well known for advocating the origin of flight in ground-running maniraptorans (Burgers & Chiappe 1999), and he includes discussion here of the wing-assisted running hypothesis. He is also highly critical of the idea that Archaeopteryx and other maniraptorans might have been scansorial or arboreal. Claims that Archaeopteryx possesses a claw geometry indicating an arboreal lifestyle (Feduccia 1993) are contradicted by newer analyses (Hopson 2001, Glen & Bennett 2007), and virtually all non-avialian maniraptorans lack features indicative of a climbing lifestyle [some very old drawings of archaeopterygids (and the Korean confuciusornithid arm) shown below].
Despite these arguments, it is likely that we will never be able to disprove the possibility that such maniraptorans as early birds, microraptorines and scansoriopterygids climbed at least occasionally; more importantly, such behaviour remains plausible based on our knowledge of living tetrapods that climb (some of which definitely lack climbing adaptations). Indeed, despite his initial argument, Chiappe does not dismiss the possibility that bird ancestry did involve the ascent of trees and other high places, and he ends this section of the book by discussing Dial's wing-assisted incline running (WAIR) hypothesis in favourable terms.
I found the discussion of another controversial topic - manual digit homology - quite satisfying. The argument from embryology (that the tridactyl avian hand must represent digits II-IV) has never been sound, relying on the identification of ambiguous embryonic structures as putative digits, and on the conservation of the embryonic fourth digit as the primary axis of condensation in the developing hand. New data from Hox genes indicates that the digit that looks like a thumb in bird embryos really is a thumb (Vargas & Fallon 2005), in which case the primary axis of condensation has shifted to another digit.
Once you do get to the birds in Glorified Dinosaurs, you're treated to sumptuously illustrated chapters on Archaeopteryx (Chapter 4), Rahonavis and other long-tailed forms (Chapter 5), the short-tailed, toothless confuciusornithids (Chapter 6), the diverse enantiornithine radiation (Chapter 7), flightless Patagopteryx and other stem-ornithuromorphs (Chapter 8), the bizarre marine hesperornithines (Chapter 9), and, finally, carinates and the origins and phylogeny of modern birds (Chapter 10) [adjacent composite shows, from top to bottom, Sapeornis, the enantiornithine Longipteryx (by Nobu Tamura, from wikipedia) and Patagopteryx (by FunkMonk, from wikipedia)].
Anyone who has been following our developing knowledge of Mesozoic birds for even just a few decades will know that the once enormous gap between long-tailed Archaeopteryx and the Late Cretaceous seabirds Hesperornis and Ichthyornis is now filled by a diverse assemblage of species, virtually all of which are short-tailed and hence united by most workers in the clade Pygostylia. Less well known is that a number of peculiar, long-tailed Lower Cretaceous birds now seem to help 'fill the gap' between Archaeopteryx and pygostylians; Chiappe's book is one of the first non-technical sources to include substantial discussion and illustration of these forms.
Responding to the 'Birds Are Not Dinosaurs' movement (again)
One thing that everybody knows about the study of Mesozoic birds is that it is a field fraught with controversy and disagreement. As a confident cladist who has always emphasised the theropodan origins of birds, Chiappe has participated in numerous debates in the literature. These have involved Mesozoic bird biology, behaviour, relationships and origins, and have often been fought against a group of authors who contend that (1) birds are not theropod dinosaurs, but descend from another group of reptiles, (2) Archaeopteryx and other Mesozoic birds were much like modern birds in morphology and perhaps behaviour, (3) Archaeopteryx, confuciusornithids and enantiornithines are close relatives, forming a Mesozoic radiation (known as Sauriurae) that occurred in parallel with the one that led to modern birds, and (4) modern birds (neornithines) descend from an obscure group dubbed the 'transitional shorebirds' that underwent a major bottleneck at the end of the Cretaceous before exploding in diversity at the start of the Cenozoic.
Like most Mesozoic specialists, familiarity with the evidence leads me to conclude that these arguments are naÃ¯ve, incorrect and based on misinterpretation or sheer ignorance. As discussed above, the morphological evidence nesting birds deep within coelurosaurian theropods is tremendously robust, the skeleton of Archaeopteryx shows that the earliest birds were much like their dromaeosaurid relatives, evidence for the monophyly of 'Sauriurae' is out-weighed by better evidence supporting a different topology, and fossil and molecular evidence indicate that the neornithine radiation did not involve hypothetical 'transitional shorebirds', and began during the Late Cretaceous, not after it.
Glorified Dinosaurs gives Chiappe a good chance to tackle the assertions made by other workers where they are contradicted by the evidence. I like the fact that he doesn't pull his punches. Take the section on bird ancestry. Keen to find any Mesozoic non-dinosaurian reptile that might be a potential bird ancestor, Feduccia, Larry Martin, John Ruben and colleagues have proposed that the bizarre Triassic reptiles Cosesaurus, Megalancosaurus and Longisquama might somehow be involved in bird origins (Feduccia 1996, Jones et al. 2000) even though they are emphatically not bird-like and lack all of the characters shared by birds and other theropods [Megalancosaurus and Longisquama shown here, by me]. Chiappe sees red, dismissing each of these wonderful little creatures as potential protobirds in turn, concluding "In the end, claims for the origin of birds from this stock of small Triassic reptiles seems to adopt a formula more apt for the world of art than for scientific endeavour, as the identity of the object (the ancestor) is defended more by its symbolism than by its own physical attributes" (p. 39).
Including the alvarezsaurids
The inclusion of a chapter about alvarezsaurids might raise a few eyebrows given that nobody supports the inclusion of these animals within the bird clade anymore. The initial suggestion that these short-armed, long-legged maniraptorans were aberrant flightless birds was immediately rejected by some, mostly because Mononykus [shown above; photo by Thomas Cowart, from wikipedia] seemed just too weird to be a bird, but also because some of its bird-like features were deemed convergences resulting from a fossorial lifestyle (Zhou 1995). As Chiappe explains, these criticisms were never logical or satisfactory. Mononykus might indeed be weird compared to Archaeopteryx, but weird lineages have evolved in many clades. As for the idea that the bird-like characters of Mononykus result from convergence, this would need to be demonstrated, not just asserted in lieu of a favoured behavioural hypothesis. As Chiappe notes, the suggestion that alvarezsaurids might be birds only amounts to the position of the lineage with respect to the node shared by Archaeopteryx and neornithines. Perle et al. (1993) found Mononykus to be one step inside this clade, but a position one, two or three nodes away would hardly be outside a margin of error, even when Perle et al.'s phylogenetic hypothesis seemed favourable. It is only a substantive issue to those who regard birds and non-avialian theropods to be well apart on the tree of life.
Nevertheless, new data and new studies agree that alvarezsaurids are not birds, though exactly where they do belong within Coelurosauria remains contentious. So, it seems strange today to include alvarezsaurids within a book on Mesozoic birds, but it's only right that - for historical reasons, at least - they be included. Numerous new taxa (including Shuvuuia, Parvicursor, Achillesaurus, Ceratonykus [skull shown here], Albertonykus, Xixianykus and Kol*), the recognition that some long-known specimens belong to the group, and studies of alvarezsaurid functional morphology have made this fascinating group the focus of continued attention.
* Jurassic Haplocheirus is an early member of the alvarezsaurid lineage, excluded from Alvarezsauridae by its describers.
The inclusion of Rahonavis from the Upper Cretaceous of Madagascar also looks somewhat peculiar. While originally described as a late-surviving relative of Archaeopteryx (Forster et al. 1998), more recent studies of maniraptoran phylogeny have found it to be a dromaeosaur closely allied to the South American taxa Buitreraptor and Unenlagia (Makovicky et al. 2005). I assumed that Rahonavis had - like the alvarezsaurids - been kept in the book for historical reasons, but it turns out that Chiappe (who is well aware of these recent studies and refers to them in his text) still thinks it likely that Rahonavis "ranks among the most primitively known birds".
A few other maniraptorans included by Chiappe in his chapter on long-tailed birds may also not be birds. Jinfengopteryx was originally described as another close relative of Archaeopteryx. However, with its closely packed teeth, proportionally robust snout and short forelimbs, Jinfengopteryx looks likely to be a troodontid (again, Chiappe is aware of this and mentions it in passing). Highlighting the great similarity between basal birds and the early members of closely related lineages is the fact that another small, early troodontid - Anchiornis - was also originally described as an early bird [adjacent Anchiornis illustration by Matt Martyniuk. Spectacular feathered specimens show that the animal really did look this like. More proof, if ever if were needed, that early members of the lineages close to birds were extremely bird-like].
There are a lot of confuciusornithid fossils these days
Among the most significant of Mesozoic bird discoveries made within recent years is that of huge numbers (possibly thousands) of the Early Cretaceous Chinese bird Confuciusornis. The enormous sample known for this taxon has provided us with a wealth of information on its palaeobiology, though again there are major disagreements between what you might regard as the 'two schools' of Mesozoic palaeornithology. Chiappe takes issue with the idea that Confuciusornis was a tree-climber that walked with a primate-like, erect-bodied pose. He also argues that the proportions of its toes indicate a ground-foraging lifestyle, not that of a percher. While the data indicating a ground-foraging habitus for Confuciusornis appears reasonable (Hopson 2001), the bird remains an enigma, as stomach contents show that it ate fish (DalsÃ¤tt et al. 2006): a diet difficult to reconcile with a supposed ground-foraging lifestyle [life restoration of Eoconfuciusornis below; by Nobu Tamura, from wikipedia. There is some doubt over the distinction of Eoconfuciusornis relative to Confuciusornis].
The reasonable amount of variation observed among the many Confuciusornis specimens has predictably resulted in suggestions that several species might be present, and that sexual dimorphism is evident. However, the morphological features used to support the validity of some of the additional species are, Chiappe argues, based on misinterpretation. One species - the apparently distinct C. dui (notable for its slightly upcurved upper jaw) - was named for a specimen kept in a private collection. Chiappe notes that the large amount of size variation present in Confuciusornis (interpreted by some as support for the multi-species model) might simply be indicative of slower growth than that seen in neornithines, resulting in the presence of subadult individuals that are living independently and alongside skeletally mature individuals. The same, Chiappe argues, might be true of Archaeopteryx and other non-neornithine Mesozoic birds.
In a few places, I do feel that Chiappe spends too much time on issues that could have been reviewed more succinctly. One example concerns his section on the long tail feathers present in some Confuciusornis specimens [long-feathered Confuciusornis shown below; by Laikayiu, from wikipedia]. This seems to stretch on for about three pages, the main point being that we cannot be sure that these long plumes are really evidence of sexual dimorphism. A series of to-ings and fro-ings in the technical literature have thrashed this issue to death with no obvious resolution (Chiappe et al. 2008, 2010, Peters and Peters 2009, 2010).
The chapter on enantiornithines does a good job of reviewing the substantial diversity now recorded for this clade. Species within this Cretaceous group ranged from the size of a finch to that of a turkey vulture, and the anatomy of their feet and rostra suggest specialisation in some lineages for wading, mud-probing, swimming, perching, fish grabbing, seed-eating and even sap-eating. The sections on hesperornithines and Ichthyornis collate a great deal of information otherwise only available in the technical literature. The volume ends with a discussion of neornithine origins. At least some neornithine clades have their roots in the Cretaceous, but the Neogene radiation of perching birds and so many others is - understandably - mentioned only in passing.
Chiappe's writing style is very enjoyable and the editing is of excellent standard. The many diagrams and photographs really are superb and the book is a visual feast, packed with huge, wonderful images (printed on high-quality glossy paper) of most of the relevant specimens. There are a few minor glitches in some of the diagrams: spaces surrounding skeletons were not correctly in-filled by the background colour. Regarding the artwork, the few reconstructions produced by Ed Heck look too cartoony, while the cover art (depicting a pot-bellied, sunken-faced dromaeosaur and a confusiuornithid with fictional wing-spurs rather than clawed fingers) bears the hallmark of an artist unfamiliar with the animals they were aiming to depict. Everything else, however, really does look great [skeleton of the rather poorly understood Chinese Cretaceous bird Jibeinia luanhera shown below].
A few details in the book are inaccurate; most concern the non-birds Chiappe discusses in the introduction. The name Lagosuchus talampayensis is used for the animal now known as Marasuchus (the Lagosuchus holotype is non-diagnostic and a referred specimen - typifying the animal that everyone had in mind when they were discussing 'Lagosuchus' - was named as the new taxon Marasuchus by Sereno and Arcucci (1994)). The archaic saurischian Herrerasaurus is said, incorrectly, to exhibit skeletal pneumaticity. Finally, Chiappe uses the term 'iguanodontids' for the ornithopod clade that includes Camptosaurus, Iguanodon and the hadrosaurs: if Iguanodontidae is to be used at all, it must be restricted to the small clade that includes Iguanodon and its closest relatives; the group Chiappe is referring to is either Iguanodontia, or its sub-group Ankylopollexia (sometimes called Camptosauria).
Glorified Dinosaurs: The Origin and Early Evolution of Birds does not disappoint. Written by one of the world's leading experts on Mesozoic birds, it is comprehensive in its coverage and lavishly illustrated. It should be obtained by everyone interested in avian history and origins, but will also be enjoyed by people interested in birds in general. Now for the production of a volume that provides similar treatment to the far more substantial Cenozoic avian record!
Glorified Dinosaurs: The Origin and Early Evolution of Birds, by Luis M. Chiappe, John Wiley and Sons, 2007, x + 263 pp., ISBN 0-471-24723-5
For previous Tet Zoo articles on Mesozoic birds (and alvarezsaurids and such), and on some of the controversies surrounding them, see...
- Tet Zoo picture of the day # 24 [on archaeopterygids]
- The new Crato Formation enantiornithine
- A stunning new Mesozoic bird... well, new-ish
- Epidexipteryx: bizarre little strap-feathered maniraptoran
- A month in dinosaurs (and pterosaurs): 2, of alvarezsaurids and avialians
- Cyril Walker
- Limusaurus: awesome and wonderful, with or without the hands (includes discussion of manual digit homology)
- Publishing with a hidden agenda: why birds simply cannot be dinosaurs (on the 'birds are not dinosaurs' movement)
- The Mesozoic birds with weird, plastic-strip-style tail structures
- Alexornis and other 'alexornithiforms'
- Aberratiodontus: worst paper ever?
- The Cretaceous birds and pterosaurs of Cornet: part I, the birds
And for previous Tet Zoo book reviews relevant to Mesozoic birds, see...
Refs - -
Brush, A. H. 1996. On the origin of feathers. Journal of Evolutionary Biology 9, 131-142.
Burgers, P. & Chiappe, L. M. 1999. The wing of Archaeopteryx as a primary thrust generator. Nature 399, 60-62.
Chiappe, L. M., MarugÃ¡n-LobÃ³n, J., Ji. S. & Zhou, Z. 2008. Life history of a basal bird: morphometrics of the Early Cretaceous Confuciusornis. Biology Letters 4, 719-723.
Chiappe, L. M., MarugÃ¡n-LobÃ³n, J. & Chinsamy, A. 2010. Palaeobiology of the Cretaceous bird Confuciusornis: a comments on Peters & Peters (2009). Biology Letters 6, 529-530.
DalsÃ¤tt, J., Zhou, Z., Zhang, F. & Ericson, P. G. P. 2006. Food remains in Confuciusornis sanctus suggest a fish diet. Naturwissenschaften 93, 444-446.
Feduccia, A. 1993. Evidence from glaw geometry indicating arboreal habits of Archaeopteryx. Science 259, 790-793.
Feduccia, A. 1996. The Origin and Evolution of Birds. Yale University Press: New Haven & London.
Forster, C. A., Sampson, S. D., Chiappe, L. M. & Krause, D. W. 1998. The theropod ancestry of birds: new evidence from the Late Cretaceous of Madagascar. Science 279, 1915-1919.
Glen, C. L. & Bennett, M. B. 2007. Foraging modes of Mesozoic birds and non-avian theropods. Current Biology 17, 911-912.
Hopson, J. A. 2001. Ecomorphology of avian and nonavian theropod phalangeal proportions: implications for the arboreal versus terrestrial origin of bird flight. In: Gauthier, J. & Gall, L. F. (eds). New Perspectives on the Origin and Early Evolution of Birds: Proceedings of the International Symposium in Honor of John H. Ostrom. Yale University (New Haven): Peabody Museum of Natural History. p. 211-235.
Jones, T. D., Ruben, J. A., Martin, L. D., Kurochkin, E. N., Feduccia, A., Maderson. P. F. A., Hillenius, W. J., Geist, N. R. & Alifanov, V. 2000. Nonavian feathers in a Late Triassic archosaur. Science 288, 2202-2205.
Makovicky, P. J., ApesteguÃa, S. & AgnolÃn, F. L. 2005. The earliest dromaeosaurid theropod from South America. Nature 437, 1007-1011.
Perle, A., Norell, M. A., Chiappe, L. M. & Clark, J. M. 1993. Flightless bird from the Cretaceous of Mongolia. Nature 362, 623-626.
Peters, W. S. & Peters, D. S. 2009. Life history, sexual dimorphism and 'ornamental' feathers in the Mesozoic bird Confuciusornis sanctus. Biology Letters 5, 817-820.
Peters, W. S. & Peters, D. S. 2010. Sexual size dimorphism is the most consistent explanation for the body size spectrum of Confuciusornis sanctus. Biology Letters 6, 531-532.
Prum, R. O. 1999. Development and evolutionary origin of feathers. Journal of Experimental Zoology 285:291-306
Sereno, P. C. & Arcucci, A. B. 1994. Dinosaurian precursors from the Middle Triassic of Argentina: Marasuchus lilloensis, gen. nov. Journal of Vertebrate Paleontology 14, 53-73.
Vargas, A. O. & Fallon, J. F. 2005. Birds have dinosaur wings: the molecular evidence. Journal of Experimental Zoology (Mol Dev Evol) 304B, 86-90.
Zhou, Z. 1995. Is Mononykus a bird? The Auk 112, 958-963.
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Darren, thanks for the detailed write-up; articles like this are a great help for those of us with little time on our hands. Seems this book is a must-read for me.
Hm. Will the journal editors be unhappy if you publish the review on your blog before it has appeared in the journal?
Is it really so difficult, actually? Kingfishers and ospreys (just to take two examples) are 'land birds' that catch fish for a living. And - on the other hand - corvids will feed on dead fish just as readily as they would on any other kind of carrion.
Permission: I am just about clever enough to make sure that the journal/its editors are ok with this sort of thing before I do it!
Fish-eating and limb proportions: kingfishers (dedicated perch-hunters) and ospreys (incredible raptorial feet) do not have foot proportions indicative of ground-foraging, but of course you're right that some terrestrial foragers (like crows) will eat food from shorelines. What I'm getting at is that the evidence from Confuciusornis is contradictory: if it was flying over the water and catching fish (which is what some researchers think), why do its foot proportions indicate ground-foraging? Does the one specimen with a fish in its gut represent normal diet or opportunism?
Looks great! Too bad it is rather on the expensive side...
Good review. I too enjoyed the book. Minor nitpick- the skeletal is of Sapeornis, not Omnivoropteryx (which might be congeneric of course, but Sapeornis still has priority).
Oh yeah, me silly :) Thanks.
OK, I just wanted to be sure that you weren't going WikiLeaks on Historical Biology. ;)
Devil's advocate: Because its recent ancestors weren't adapted to piscivory? (For an opposite example, consider the long-tailed skua Stercorarius longicaudus: it's a 'waterbird' by anatomy and by ancestry, but it feeds near-exclusively on terrestrial rodents for much of the year.)
From the main post:
Post-k/T fossil avians don't seem to generate any particularly wide interest, unfortunately.
Sounds like a great book! An interesting thing I've recently heard is that Larry Martin has softened his once-dogmatic opposition to the dinosaur-bird link, pointing out the clear similarities between the anatomies of modern birds and Dromaeosaurs. I welcome this, even if he's come to the party a little late, and it makes me wonder if some of the other few opponents of the dinosaur-bird connection will come around as well!
When did NGMC 91 get referred to Microraptor? The last I knew, it was still "Cf. Sinornithosaurus".
Amazon UK lists only used copies at colossal prices. Is the book out of print?
I haven't seen the book, but the "peculiar" inclusions probably go farther in refuting BAND than any arguments actually presented. As we begin to see how evidently difficult it is for experts to agree on how to distinguish a bird from other maniraptorans, it seems increasingly ludicrous to insist they are separate lineages.
Excepting putative human ancestors, hardly anything from the Paleocene to the Pliocene commands appreciable popular attention. It's a major shame.
(Don't get me started on the popular coverage of paleozoic anything.)
I love the fact that the dromaeosaur on the cover can't bring itself to lift its arms--which must be incredibly heavy--and its face looks like something out of The Dark Crystal. It seems to lack a pubis and ischium, as well.
Thanks for comments.
Dartian (comment 7): yes, you might be right (on 'terrestrial' signal of hindlimbs not necessarily telling you what the animal was doing). As I've said at least a few times, 'anatomy is not destiny', and animals will sometimes do what they can, because they can. I want to emphasise, however, that we need more data. Confuciusornis looks superficially kingfisher-like, is found in close association with aquatic environments, and (in one specimen) has fish preserved as stomach contents. However, it still might be possible that it was a folivore or omnivore as some workers say.
Raymond (comment 8): Martin and colleagues have been saying for a while now that dromaeosaurs and some other maniraptorans are indeed so bird-like that they are surely close kin of birds. Their conclusion? (1) That these maniraptorans are actually flightless birds (as per Greg Paul). (2) That birds are still nothing to do with those oh-so-horrible reptilian dinosaurs, but represent the descendants of, well, anything but a dinosaur. See the 2008 comment here.
Mike (comment 9): NGMC 91 is still cf. Sinornithosaurus - I think you've been confused by where I placed the image caption (sorry). Just for you, I'll go change it.
Finally... I had no idea the book was now being advertised at such high prices. Amazon.co.uk lists it at Â£95, which is obscene. Sorry, not much I can do about that. Other than say this again.
I do think that the scansoriopterygids climbed a lot; their feet look like those of Jibeinia. The other nonavian pygostylians, though? Naaaaah.
It has a mammalian pelvis, sorry, pair of innominates just like how it has mammalian forearms and an almost mammalian tail. Oh, and, those stupid wing fingers on the upper arms, where they don't belong (even Archaeopteryx lacks tertials), combined with a total lack of feathers on the hands.
I hope the publisher picked that artist and Chiappe has put the skull of a brontothere into their beds.
That poor thing on the cover is really a proto-mammal that (convergently) invented feathers, but did not employ they well. It was outcompeted by the birds (who did), and left no fossil trace. Just another one of evolution's blind alleys.
I happen to know that the artist who did that cover has done several other published dinosaurs, mostly for the American Museum of Natural History team. I think their work is symptomatic of large problem in paleoart. SOME artists don't know the anatomy and do bad work, but the paleontologists who check it know even less and so don't criticize it!!
I was looking for a different book to read on Dinosaurs and I think this might be the one to get.
Thanks for the great blog - enjoy it a lot
With so many good books on dinosaurs, birds and the evolution and ecology of these animals, is there any such books like these for our worthy synapsid kin? Especially a good one on the evolution of mammals for the layman.
On the early history -- non-mammalian synapsids and the origins of mammals -- look for T.S. Kemp's book, though it's written in a style that is more textbookish than popular. The latest version (I forget the title) compresses the pre-mammal stuff a bit so as to have room to cover later, including Cenozoic, mammalian developments: the earlier version from the 1980s, "Mammal-like Reptiles and the Origin of Mammals" (I think) may be a bit dated but may still be the best starting place for Pelycosaurs and Therapsids.
Another, shorter, book from the 1980s, Kermack and Kermack (husband & wife team, I think) "The Evolution of mammalian Characteristics" (again, not 100% sure I have the title 100% right) is my personal favorite: short, clearly written, describes the anatomical high-points and discusses their possible adaptive relevance: can be read like a novel or a history book.
If you win the lottery or have access to a university library, try for Kielan-Jaworowska, Cifelli and Liu, "Mammals from the Dinosaur Era": coffee-table size review of everything known (as of 1996 or so: just prior to the announcements of Castorocauda, Fruitafossor and Volaticotherium) about Mesozoic mammals: brief descriptions of every known taxon, but also longer reviews of general themes (such as the origin of the tritubercular molar) and detailed descriptions of the better-known types.
McLoughlin's Synapsida is a wonderful read, albeit outdated (written in the '70s) and the author has some idiosyncratic ideas. (Same guy as advocated ceratopians with the frills embedded in the animals' backs.)
For Cenozoic mammals, you might want to try Rose and Archibald's The Rise of Placental Mammals.
Aye; Stephen Jay Gould wrote that book about the Burgess Shale critters, and that's pretty much it.
Riggi: On Cenozoic mammals of the world, see
Prothero, D.R. 2006. After the Dinosaurs: The Age of Mammals.
On Cenozoic mammals of South America, see
Simpson, G.G. 1980. Splendid Isolation: The Curious History of South American Mammals.
On Cenozoic mammals of Europe, see
AgustÃ, J. & AntÃ³n, M. 2002. Mammoths, Sabertooths, and Hominids: 65 Million Years of Mammalian Evolution in Europe.
On Cenozoic mammals of Africa, see
Turner, A. & AntÃ³n, M. 2004. Evolving Eden: An Illustrated Guide to the Evolution of the African Large-mammal Fauna.
On Cenozoic mammals of Australia, see
Long, J., Archer, M., Flannery, T. & Hand, S. 2002. Prehistoric Mammals of Australia and New Guinea: One Hundred Million Years of Evolution.
That's a reprint, right? Isn't the original from the 1950s?
No, it's the year of original publication; Splendid Isolation was Simpson's last book (IIRC).
I was at a conference last week and heard a presenter mention, somewhat offhand, that there was a hypothesis proposing an aquatic origin of bird flight. (he preferred an assisted incline climbing and slowed falling purpose for pre-flight adaptations). Must there be a weird aquatic hypothesis for the origin of everything? Anyone know anything about this one?
Deinonychus shown here; by Arthur Weasley, from wikipedia
As was the Castorocauda in the Tet Zoo 1 book by Arthur Weasley, by way of Wikipedia.
In both cases Nobu Tamura might be an alternative name for the artist, but I would be delighted to find that a real person Arthur Weasley existed.
Excellent article/book review, Darren. I think I'll seriously have to try to get this book!
(And I would like to say that I sincerely apologize for posting multiple tons of overzealous crap on your blog in times past, lots of which I donât agree with myself anymoreâ¦)
The one offputting thing about this book must be the dromaeosaurid on the cover. I guess there's a reason for that famous saying...
Aquatic origin of bird flight: that's
Ebel, K. 1996. On the origin of flight in Archaeopteryx and in pterosaurs. Neues Jahrbuch fÃ¼r Geologie und PalÃ¤ontologie, Abhandlungen, 202:269-289.
(Here and here)
Thanks for the review. It's too bad that Chiappe stops just where things get really interesting (at least from my perspective), with the early evolution of Neornithes.
Have you perhaps reviewed, or intend to review, Gerald Mayr's book Paleogene Fossil Birds? I've only seen a couple of chapters, but it might do the trick.
It's a real shame that nobody has done a comprehensive, popular/semi-popular volume on Cenozoic birds (COUGH COUGH someone might be working on one right now COUGH COUGH)... I do indeed have a review copy of Gerald Mayr's book but, err, haven't published a review of it yet. Mayr's book is nice, but way too specialised and technical to have anything more than specialist appeal.
Not to mention that it's ridiculously expensive. I mean, even for an academic book.
I'm assuming you're hinting about your secret project. I do hope you also go into Mesozoic neornithines, fragmentary as they are. Why does the DNA tell us modern birds were diverse at the K/T boundary, and put the basal node at c. 120ma, while they're so rare as fossils before the Paleogene? Were they originally limited to South Gondwana?
And I call them neornithines only for clarity. I really want to call that node Aves. Crown group definitions for all extant groups!
That 'secret project' is something else - hopefully to appear this year (we can but dream). I probably will stick with calling crown-birds neornithines, but these days I am a big advocate of using Avialae for the Archaeopteryx + modern bird clade.
Meh. I've become the opposite over the years. As more fossil birds are discovered, I'm liking the idea of using the term "Avialae" for crown-group birds only.
Darren, you are a coy rascal. So now you have two secret projects?
If you use Avialae for the Archaeopteryx + Passer clade and Neornithes for the Struthio + Passer clade, whatever do you do with Aves? As far as I can see, the only sensible alternatives are Aves/Neornithes and Avialae/Aves to name the two previously mentioned clades, of which I prefer the latter set of names. I believe that Mammalia has largely switched to crown group usage; why not Aves?
And Zach, if you use Avialae for crown birds, what happens to Aves and Neornithes?
Only two secret projects? Heavens, no... many more than that :) Don't worry, you'll hear about them first on Tet Zoo.
On names, the vernacular 'neornithines' for crown-birds is definitely better than 'avian', but I'm with you on formally restricting Aves to the crown. Frankly though, Aves has become a pain in the ass, since differing usage means that it's no longer unambiguous. Avialae, on the other hand, is always maximally inclusive (Zach, take note).
FWIW, I've become sympathetic to the idea of just dropping Aves. Despite Zach's efforts (:p), Avialae and Neornithes are much less liable to cause confusion.
As a general thing, I'm dubious as to the wisdom of using the best-known names (eg. Aves, Amphibia) for the crown groups when there are less ambiguous names available for those (eg. Neornithes, Lissamphibia).
I also want to complain about Michel Laurin's use of Stegocephali to mean Acanthostega + Homo (read How Vertebrates Left the Water Thursday-Friday), but I'll be damned if I can make it topical. :p
It isn't easy to calibrate molecular dating studies correctly. I bet that's what happened here.
Brochu, C. A., C. D. Sumrall, and J. M. Theodor. 2004. When clocks (and communities) collide: Estimating divergence time from molecules and the fossil record. J. Paleont. 78:1-6.
Brochu, C. A. 2004. Patterns of calibration age sensitivity with quartet dating methods. J. Paleont. 78:7-30.
van Tuinen, M., and B. S. Hedges. 2004. The effect of external and internal fossil calibrations on the avian evolutionary timescale. J. Paleont. 78:45-50.
Waggoner, B., and A. G. Collins. 2004. Reductio ad absurdum: Testing the evolutionary relationships of Ediacaran and Paleozoic problematic fossils using molecular divergence dates. J. Paleont. 78:51-61.
Brochu, C. A. 2004. Calibration age and quartet divergence date estimation. Evolution 58:1375-1382.
Brochu, C. A. 2006. Empirical exploration of calibration sensitivity in molecular dating methods â maximising the role of palaeontology in molecular evolution. P. 138 in Q. Yang, Y. Wang, and E. A. Weldon, eds. Ancient life and modern approaches. University of Science and Technology of China Press, Beijing. [abstract from the 2nd International Palaeontological Congress]
MarjanoviÄ, D., and M. Laurin. 2007. Fossils, molecules, divergence times, and the origin of lissamphibians. Syst. Biol. 56:369-388.
San Mauro, D. 2010. A multilocus timescale for the origin of extant amphibians. Mol. Phyl. Evol. 56:554-561.
Why call that clade anything? What if Archie turns out to be a troodontid tomorrow?
That's purely your idea, you know.
I should publish my branch-based definition already.
I just have so much more urgent stuff to do...
Because the mammalian crown-group is almost as big as the clade(s) traditionally called Mammalia. The difference is probably just the few Triassic and Early Jurassic forms and the docodonts. In birds it's different; it's as if there were no monotremes, or if Shenzhouraptor had left extant descendants.
I thought you wanted to decrease the chaos? How would anyone go about separating "Aves" from "avian"?
Eh, so do I. Nothing wrong with naming that clade, but that name best rests in pieces.
Thanks for some nice references, but I don't think so. There are a few good pre-K/T calibration points (notably Vegavis) that require considerable diversification well before the boundary. Maybe not 120ma, but I can't see it dropping much blow 100ma. Unless Vegavis is somehow badly misplaced on the tree.
Why crown groups? For the reasons Gauthier & De Queiroz have stated. We know more about crown groups than other groups; they're the meanings most often intended by neontologists, i.e. most biologists; it makes the decision simple.
What's your branch-based definition? Passer -> ...? And why that one, particularly?
Yes, Vegavis shows that several cladogeneses within Anseriformes must have taken place a bit before the very end of the Maastrichtian. Given the position of Anseriformes within Neornithes, that translates to... about five cladogeneses, right? Palaeognathae/Neognathae, Gallanseres/Neoaves, screamers/other anseriforms, Anseranas/other anseriforms, Vegavis/Presbyornithidae/Anatidae? (Presbyornithids are AFAIK known from the K, I think early Maastrichtian... the Mongolian Cretaceous is difficult to correlate with marine sediments. And if Brontornis, Gastornithidae and Dromornithidae are taken into account, the number of cladogeneses within Anseriformes could rise.)
However, that's pretty much it. There are a few isolated left coracoids from the Maastrichtian of North America that might belong to something maybe similar to a procellariiform and/or charadriiform and/or who knows what... there are Polarornis and Neogaeornis that could be loons (P. was described as such after being heavily reconstructed from tiny fragments), but van Tuinen & Hedges 2004 (citation above) dealt with that very effectively.
No. Most often, neontologists don't know what precisely they intend, and use several different meanings in the same paper. Commonly they use a well-known taxon name for a similar but not identical clade, even when both are crown-groups. Most neontologists hardly know better, and they don't care.
Remember the Nature paper on the ancestral vertebrate karyotype? "Vertebrate" my ass. It compared the fugu genome to those of various tetrapods, making the reconstruction the ancestral osteichthyan karyotype. Several names are used several different ways each in that paper... I'll need to dig it up, and maybe 1 or 2 others.
Yes, Vegavis' topological position implies 5 divergences. But to say that's all the tree implies you have to decide that branch length is meaningless. There's a lot of molecular evolution between Vegavis and the root, and one must presume that took some amount of time.
And thus the mystery that the fossil record doesn't seem to show much of what should, by the tree, be there. I'm going with a geographic sampling problem until further notice.
Your condescension to neontologists is unwarranted. Of course there are a lot more neo than paleo publications, and I'm sure you can find more examples of problems with taxon names. But we were talking about Aves here.
As for continuity shouldn't you be using the usual node-based one with Archaeopteryx as reference taxon if that's your goal? Is it because you're concerned about the possibility that you might have to admit troodontids or dromaeosaurs? And what's your external reference taxon of choice?
Damn. Well, I'm just confused, then. I thought Aves was a broader term than Avialae. Sorry, guys. Well, what's Neornithes used for right now? Enantiornithines + Ornithurines?
Re: John Harshman (#35)--
You say: "I believe that Mammalia has largely switched to crown group usage; why not Aves?"
With "Mammaliaformes" (should be "Mammaliformes," but classical scholarship seems to be in decline among paleontologists) for the more inclusive group that starts with the Triassic furries. On the other hand, Kielan-Jaworowska, Cifelli and Luo, "Mammals from the Dinosaur Era," the review of early mammalian evolution that will likely be the standard reference and starting-point for a few years to come, define Mammalia as Sinoconodon + living types. There is an arbitrariness to the choice (why not Adelobasileus + crown? or, in the other direction, Morganucodon + crown?), but going for a crown group is also arbitrary: what gets into the crown depends on historical accident! (It's not clear whether the Miocene New Zealand furry is inside Ornithorhychus + Homo, so for mammals the historical accident might be quite recent!) I think that Sinoconodon + crown is good, preserving continuity with most older literature.
Neornithes is the avian/dinosaurian crown group (what I would prefer to call Aves).
Crown-group definitions are non-arbitrary in one sense: they provide a general rule for taxon definition in living taxa that, if followed uniformly, gives some automatic idea of what a name means. We are also assured that crown-group taxa possess all the synapomorphies, soft-tissue as well as osteological, that are supposed to characterize the taxon. Accidents of extinction might be considered arbitrary, but they're also unavoidable givens. Mammaliaformes and Avialae are just fine for broader groups, and we can declare as many of those as we feel like. Choosing among Sinoconodon, Morganucodon, and whatever others we might enjoy as reference taxon seems extra-specially arbitrary to me. Why one over another at all?
Aves = all things conventionally considered 'birds' (from Archaeopteryx to extant species) for many workers, but restricted to the crown by some (crown = the clade containing living species and their most recent common ancestor). However, even those who prefer use of an 'inclusive' Aves have defined it as node-based (for the Archaeopteryx + modern birds clade), in which case there will still be 'birds' that aren't in Aves.
Avialae = absolutely everything on the 'bird' branch of Maniraptora. So, if dromaeosaurids, Anchiornis or Archaeopteryx or whatever do belong on the same branch as crown-birds, they are in Avialae. This is why it's a better name for the whole bird clade than Aves. Also, if Archaeopteryx is not on the bird branch (a very real possibility), it's not in Avialae.
Neornithes = crown-birds only. So, palaeognaths and neognaths and NOT any of the Mesozoic groups such as enantiornithes.
A few other names worth knowing...
Pygostylia = a node-based clade including confuciusornithids and crown-birds (in other words, [nearly] all birds with a true pygostyle).
Ornithothoraces = the node-based clade including Iberomesornis and crown-birds; in other words, the enantiornithine + crown-bird clade.
Ornithurae = mostly used for the node-based clade that includes hesperornithines and crown-birds, but (confusingly, yet more in keeping with original proposal) used by some (notably Sereno) for all birds closer to the crown than to Archaeopteryx. Because we need to refer to the former clade more than the latter, I prefer the less inclusive version of Ornithurae. Note that Pygostylia is not as inclusive as the 'most inclusive' version of Ornithurae, so they aren't synonymous.
Ornithuromorpha = generally used as a node-based clade that includes Patagopteryx and modern birds. It is frequently useful for 'post-enantiornithine' birds.
@43 Allen Hazen
What is the name of the "Miocene New Zealand furry"?
@45 Darren Naish,
if Archaeopteryx is not on the bird branch (a very real possibility)
That's something I would like to hear more about!
Avialae has two definitions, both by Jacques Gauthier (who generally believes he owns the names he created). The older one is node-based: Archaeopteryx + crown. The newer one is branch-based, but I forgot what the external specifier is. Oh, and, of course there's an apomorphy-based one (from the literal meaning of the name, "bird wings") by Gauthier, Clack and maybe others, but it's only from 2001, and I don't think anybody else has used it.
My condescension to the argument by paleontologists that "neontologists use it that way" is warranted: few of the neontologists are phylogeneticists or care about phylogeny at all except in the most superficial ways. I know, of course, that you are a phylogeneticist!
Yes. They have long been considered close relatives of the birds, but practically never birds themselves.
There's a long list that I'll try to dig up later. A troodontid and several dromaeosaurids are among them (several to account for the possibility of dromaeosaurid paraphyly, an idea that was occasionally floated in the early 2000s).
Same thing it's always been used for: the crown-group (Palaeognathae + Neognathae).
Enantiornithes + Euornithes is Ornithothoraces and has always been (...since Iberomesornis was recognized as an enantiornithean in 1998). Ornithurae has several very different competing definitions and is perhaps best dropped; the most common usage could be for a subset of Euornithes (namely Hesperornithes + Neornithes or suchlike).
Ornithuromorpha has two definitions by the same people, both node-based. The older one is Patagopteryx + crown; when it was coined (in the paper that describes Vorona), P. and Vorona formed a trichotomy with a clade that contained the crown. In their next paper, this trichotomy was resolved, with
Euornithes, which is older than Ornithuromorpha, is branch-based like Enantiornithes: it's everything closer to the crown than (to) Sinornis. I don't know why more people don't use it; perhaps because Sereno published the name in a paper with 80 small pages in the Neues Jahrbuch fÃ¼r Geologie und PalÃ¤ontologie which seems to be not very widely available outside central Europe or so.
Luo Zhexi told me at the SVP meeting of 2008 that he, and just about everyone else, now uses Mammalia for the crown.
Funnily enough, this leaves the (Sinoconodon + crown) clade without a name. Mammali"a"formes is Morganucodon + crown, and Sinoconodon is one node farther out in all recent phylogenies. When the name Mammaliaformes was coined in the 1980s, M. and S. formed a trichotomy with a clade that included the crown, so it didn't matter...
To really preserve continuity, you'd need Adelobasileus, which is only known from an isolated braincase.
And then Sapeornis was discovered.
Fortunately, Gregory Paul has taken care of this by coining the apomorphy-based name Avebrevicauda* for those with 10 or fewer free vertebrae between sacrum and pygostyle; this includes Pygostylia and Sapeornis/Omnivoropteryx.
* Literally "birdshorttail". Not a kind of birds, but a kind of tail.
No name was created, because the animal is so poorly known.
On Avialae - nope, Gauthier (1986, p. 36) specifically says that it's branch-based: "... the name Avialae is applied to Ornithurae plus all extinct maniraptorans that are closer to Ornithurae than they are to Deinonychosauria". On Pygostylia, I stupidly forgot about Sapeornis. You know that some workers intimate that Sapeornis might be part of Pygostylia? At least, this is what Chiappe says in Glorified Dinosaurs - I can't recall seeing it recovered in an analysis.
Much of this discussion reminds me of why I have become less than enamored of phylogenetic definitions in the absence of topological clarity. You generally have an idea of what you want to be included and what you want to be excluded, and you may end up, if the tree turns out differently from what you initially thought, defining a group that doesn't fit your expectations, or that your name is now a junior synonym of some other name. You may find that Avialae includes troodontids, for example. I also happen to prefer node-based groups, in general, and they're especially vulnerable to this problem. You can fudge a branch-based name with tons of external specifiers and usually end up excluding all the taxa you don't want, but you still run the risk of excluding some of the taxa you do want. And if you use multiple internal and external specifiers, you may end up with a self-contradictory definition. My solution? Wait until the tree is clarified before naming. (This, by the way, is one benefit of neontology: we have greater prospects of clarifying that tree due to the vast expandability of data sets with molecular data. And thus we have a fine argument for crown group names, whenever possible.)
John, that all sounds very noble and reasonable. But (1) the damage is already done: even if you're a restrained, conservative phylogeneticist, other workers will paste names all over the tree before you get to it (and they have, oh how they have), and (2) we need shorthand! Everyone knows that there's more than one definition of (say) Avialae and Aves; ergo, you just have to be sure to cite the definition you're employing.
On the subject of phylogenetic definitions, did you know that Dinosauria = Tyrannoraptora, Ornithischia = Tyrannosauroidea, and Saurischia = Tyrannosauridae? It's all in Martinez et al.'s recent Science paper on Eodromaeus.
I will, however, continue to stand athwart the tide of history, yelling "Stop!". We need names, but we don't have to nail all of them down tightly just yet. That way lies Tyrannosauridae.
Tyrannosauridae, etc: Thanks for bringing it to my attention. The first two seem to be typos in which the authors thought "Triceratops horridus" but typed "Tyrannosaurus rex". Oopsie. But Saurischia seems to be a straight substitution of Sereno's definition of Tyrannodauridae. Bet they were horrified to see that in print.
Thanks for the help, guys. I'm gonna have to make myself a nice little document with these names and definitions and stick it on my fridge. :-)
[from Darren: sorry, delayed by spam filter]
Meet the qualifying clause.
Then the name doesn't apply to any clade and perhaps shouldn't have been used in the first place; if you can't save a traditional grouping because it turns out not to be monophyletic, stop trying.
Alternatively, emend the definition as described in Article 15.8 onwards.
It's science we're talking about. There is no "clarified"; and when there is, we can't prove it is.
There are things like Recommendation 9B, though. (Scroll to the bottom.)
Molecular data come with their own set of problems. That's why you are among the first people to have found that "Ratitae" is paraphyletic, after 7 years of serious and maybe 20 years of baby-steps molecular phylogenetics of birds.
To rid us of exactly this problem is the first and foremost basic purpose of the PhyloCode.
A bit biased towards Sereno's own definitions, but not much.
"A bit biased"?? Hah!
Random replies to David M.
Why I prefer node-based groups: no rational reason.
Though a node can never be absolutely certain, and is always subject to challenge by new data or analyses, some are less dubious than others. We should name whose membership we are reasonably confident of. 9B is nice, but doesn't deal directly with that issue.
Sure, molecular data have problems just like any other. But quantity has a quality all its own. Some problems that are difficult with morphological data become easy with molecular data. (The problems that are easy with morphological data were all settled a long time ago.) Some problems that are difficult with mitochondrial data become easy with nuclear data. The more of the genome you access, the easier it becomes to see problems in bits of it. All of this suggests to me that crown groups should be used when you can.
As for ratites, I will point out that we are the first to address the question seriously using nuclear data, and that new mtDNA analyses have finally managed to agree with us. The two major prior mt papers -- Haddrath & Baker and Cooper et al. -- had bizarre problems. The former actually constrained ratite monophyly (!) while the latter failed to consider site-to-site rate heterogeneity, commonly a fatal error in deep mt analyses. But sure. All types of data can be problematic in the wrong circumstances.
And one should always appreciate that Andrzej Elzanowski managed to find a set of cranial characters supporting ratite polyphyly, none of which to my knowledge has ever been incorporated into anyone else's morphological analyses, notably Livezey & Zusi's.
Haddrath, O., and A. J. Baker. 2001. Complete mitochondrial DNA genome sequences of extinct birds: Ratite phylogenetics and the vicariance biogeography hypothesis. Proceedings of the Royal Society of London, Series B 268?:939-945.
Cooper, A., C. Lalueza-Fox, S. Anderson, A. Rambaut, J. Austin, and R. Ward. 2001. Complete mitochondrial genome sequences of two extinct moas clarify ratite evolution. Nature 409:704-707.
Elzanowski, A. 1995. Cretaceous birds and avian phylogeny. Courier Forschungsinstitut Senckenberg 181:37-53.
Livezey, B. C., and R. L. Zusi. 2007. Higher-order phylogeny of modern birds (Theropoda, Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion. Zoological Journal of the Linnean Society 149:1-95.
When I was in grad school I took a macroevolution course that was co-taught by professors from the anatomy, genetics, & E&E departments. There was an anatomy professor who was certain that cetaceans are mesonychids, based on both groups having had a supposedly homologous non-trochleated astragulus. She also was adamant about taking a "total evidence" approach to phylogenetic analysis, i.e., of combining both morphological & molecular characters in the data set. For her contribution to our mid-term exam, she gave us a paper to critique whose authors had used LINEs & SINEs in the cetacean genome to show that cetaceans are in fact artiodactyls. I had to review Nei & Kumar, or someone, about what LINEs & SINEs are, and the outcome was that I became rather convinced that the authors were correct; that cetaceans are, in fact, artiodactyls rather than relict mesonychids. I wrote what I thought was a reasoned explanation for why I agreed with this conclusion.
Well, this was not what the professor wanted to hear. She returned my essay all marked up with red: "..but what about total evidence.. what about that tarsal bone.. blah, blah..," and gave me a mediocre grade. I wasn't particularly pleased but since I scored well on essay questions assigned by the other professors, I didn't complain. It wasn't long before Gingrich, I think it was, described a beautiful series of transitional fossil whales, showing that that supposedly homologous astragulus in mesonychids & cetaceans was patently homoplasious. I felt like taking that paper into the professor's office & slapping it down on her desk.
I won't ask where or who, but there used to be many places that were like that. These days, "total evidence" analyses tend to have topologies identical (for extant taxa, that is) to those of the molecular data alone, since there's just so much more of it.
Apropos, from PLoS One:
Ha! John, I don't think you need to ask..
Sheesh, talk about singing a different tune..
Yeah, maybe it has changed in the 5 years since I last had a look there. :-)
since there's just so much more of it.
Though that's exaggerated by the fact that gathering molecular data has become much, much, much easier than gathering morphological data. Livezey & Zusi 2007 is the biggest morphological data matrix to date â the biggest of all fields, by far; it has something like 2000 parsimony-informative characters. Not only do most molecular data sets surpass this these days, you just found parsimony-informative morphological characters that Livezey & Zusi overlooked. (And cranial ones at that. With all the craniocentrism in vertebrate matrices, one might think the skull has been exhausted as a source of data for phylogenetics. One would, evidently, be wrong.)
(While I am at it, the sampling of fossils by Livezey & Zusi is... just... pitiful. But I digress.)
It wasn't long before Gingrich, I think it was, described a beautiful series of transitional fossil whales, showing that that supposedly homologous astragulus in mesonychids & cetaceans was patently homoplasious. I felt like taking that paper into the professor's office & slapping it down on her desk.
I'm surprised you didn't. This is something I would have greatly enjoyed doing. Then again, the professor probably would have brushed off Rodhocetus (or whoever it was) saying that, at the time she gave that lecture and grade, the "total evidence" said otherwise. Then I would have started cursing...
In one of those weird coincidences that happen so often in science, Thewissen found roughly the same sort of thing -- e.g., a whale astragalus -- that Gingrich did, at about the same time, and their papers were published in different high-impact journals at about the same time. And of course they demolished the anti-whippo argument at about the same time.
Re: Gerdien de Jong--
As to the new Zealand Miocene Mammal(iamorph)...
Here (only because it was the first Google hit I tried) is the "New Scientist"'s article:
which at least has a reference to the original publication in PNAS. (Darren discussed it in a "Tet Zoo ver I" post.) Very fragmentary remains (the symphysis of a lower jaw, suggesting procumbent incisors and otherwise a morphology different from what would be expected in any known group of Mammal(iamorph)s, and the upper end of a femur (or humerus) with an angle suggesting a sprawling posture. In what strikes me as an admirable and very unusual display of restraint, the authors of the original report (Trevor Worthy and others) refrained from giving it a name: it wasn't certain that the different pieces were from the same critter, so they didn't think their "taxon" was well-enough documented to merit naming!
re #44: I think it comes to a value judgment: I think preservation of traditional usage (with the smallest feasible adjustments) is more important than you do. I think we agree on factual mattrers and understand each other.
re #59: It is good that O'Learey (who, i.i.r.c., favored the Cetacea-Mesonychia link in her early publications) now believes in Cetancodonta: she is not geing another Feduccia! But I'm not sure we should be VERY confident of the details of the phylogeny presented in the paper you link to. Note that it puts Perissodactyla closer to Cetartiodactyla than to Ferae, and so is inconsistent with Pegasoferae (which HAS to be true becaaue it has a cool name (Grin!)), and also that it is sensitive to taxon sampling: the discussion at the end admits that omitting one or another taxon from the analysis radically changes the topology for the others! What would happen if they had included a basal Chiropteran?(*)
(*) That was a rhetorical question: my GUESS is that the earliest known bats are already so derived that they wouldn't attract Perissodactyla... but you never know!
On two consecutive days.
Yeah, it needs loads more taxa. Patriofelis (the only included oxyaenid) nested within Hyaenodontidae, as the sister-group to Hyaenodon even, and all together as the sister-group of Carnivora + Vulpavus? Strikes me as "they had no other place to go". The same holds for Protungulatum, which may not even be a placental (Wible et al. 2007).
The same even holds for Eocene artiodactyls. There's weirdness by the ton in there, enough that I'm not confident with saying the published morphological analyses say anything about the phylogeny of Artiodactyla (beyond weakly confirming Whippomorpha Cetancodonta). The biggest mystery isn't where the whales sit, it's where the ruminants sit.
Time to recycle that article, Darren?
This is a generous assessment, Allen. Thank you. Yes, it is good that she's not turned into another Feduccia or Milford Wolpoff. Still, she was dragged to the modern interpretation kicking & screaming. She conceded her position only long after the consensus grounded in molecular systematics had become established, and only after the discovery of new fossil evidence supported the molecular based phylogenies. Her bias in favor of analysis based on morphological characters - which I suppose is only natural for an anatomist - was blatant. And once she did concede the point, she characterized her former position as having only been a hypothesis. Well, sure.. a hypothesis the correctness of which she was so invested in that she wasn't above penalizing students who questioned it.
A good review of book well worth reading. Thanks!
There's just one thing I want to mention. The guy who draws prehistoric animals (such as that Deinonychus) for Wikipedia is not called Arthur Weasley. Mr. Weasley is a character from Harry Potter books.
The artist's name is Nobu Tamura, and supposing you haven't agreed with him to use the now-abandoned Wikipedia username instead of his real name, I wonder if he likes being always misnamed. The name of Arthur Weasley even appeared in the Tetrapod Zoology Book One.
If using the nickname was on purpose, forget my nitpicking. :)
Thanks for that info, Maija. When I credited those images to 'Arthur Weasley' I honestly thought that this was the real name of the artist: after is, this is exactly how they were credited on wikipedia, and it's far from impossible that a real person might really have this name (whether it's in the Harry Potter books or not). The publisher of Tetrapod Zoology Book One did indeed tell me that the name was a pseudonym, but I decided not to follow their advice. I later realised that 'Arthur Weasley's' pictures were extremely similar to those credited to Nobu Tamura, and I now know that they are the same person. I hope that this honest mistake is not offensive to the artist. I very much appreciate their work and am grateful for the fantastic service they provide!
Where is the beef? Can any paleontologist point to me which drawer in any of the world's numerous museums may contain the ancestor of birds? I know that cladists try to dodge a question like this by claiming that ancestors can never be found. That is nonsense. We have already found the ancestor of modern humans, i.e. Homo erectus. We have found the ancestor of whales, namely Rodhocetus. In fact, we have also found the ancestor of birds, Longisquama, which has feathers. Of course cladists will accept all of these claims except for Longisquama as bird ancestor. So, where is the cladists' hypothesized ancestor of birds. It cannot be Velociraptor or Deinonychus, because they are younger than the first known bird Archaeopteryx. So, once again, where is the beef?
I'm rather hoping David MarjanoviÄ spots that last comment. I'll be listening for the k-ching noise of the claws coming out in France.
Cal King: why do you make a point of not paying attention? (in other words, of constantly betraying your own ignorance?). Close maniraptoran relatives of birds that pre-date Archaeopteryx are now known, with some of the best examples being Pedopenna daohugouensis (housed at the Institute of Vertebrate Paleontology and Paleoanthropology) and Anchiornis huxleyi (many specimens, housed in the collections of the Liaoning Paleontological Museum and Institute of Vertebrate Paleontology and Paleoanthropology). These two are far from alone - other maniraptoran fossils that pre-date Archaeopteryx have been known for decades. A relatively poor Middle Jurassic fossil record does mean that we're unlikely to find actual bird ancestors (this was a time of unprecedentedly high sea stands); I think the best we can hope for is close relatives of such ancestors, and this is what we have.
Longisquama has no similarity with birds (or other maniraptorans) and there is no reason to think it's anything to do with bird/theropod/dinosaur evolution.
I did, and wrote a reply. But when I tried to submit, the DDoS attack struck.
Fortunately I press Ctrl+A and Ctrl+C every time before I submit a comment to the ScienceBorg.
How can we recognize an ancestor as an ancestor?
If it lacks autapomorphies (derived features not shared by its closest relatives) and is older than its possible descendants, then it enters consideration for being accepted as an ancestor.
Determining that autapomorphies were lacking is of course impossible from bones alone.
If the fossil record of the time and place in question is so breathtakingly good that it becomes too improbable to assume that another closely related clade existed at the same time (and was the true ancestor), then and only then it becomes the most parsimonious hypothesis to suppose that the species in question is an ancestor. For Homo erectus in the wide sense, this is the case: it is fairly safe to assume there wasn't yet another kind of human running around in Africa at the same time.
(Of course, for Homo erectus in the narrow sense, that is not the case. H. erectus sensu stricto contains only the younger Asian specimens; people who use the name H. erectus in its strict sense call the older Asian and the African specimens H. ergaster, and that is our ancestor.)
This is... just... fractally wrong. No matter how closely I look at it, it's still wrong.
Where to even begin?
â¢ AFAIK, R. does of course have autapomorphies.
â¢ You see, there's a reason phylogenetic trees are called trees and not poles. The diversity of life is huge and has been huge for a very long time; the probability that any particular fossil is an ancestor of anything known is ridiculously low -- it almost certainly lies on some side branch or other, even if we can't find autapomorphies.
â¢ ...and usually we can find autapomorphies. Most fossil "species" that were thought to lack any have been shown to possess some; this includes Archaeopteryx.
â¢ "The ancestor of whales"? In the singular? How stupid. We've got an entire tree of transitional forms, not just one! Indohyus and its fellow raoellids; Pakicetus, Ichthyolestes, Himalayacetus, Nalacetus; Ambulocetus; Remingtonocetus, Dalanistes; Rodhocetus, Maiacetus; Gaviocetus, Takracetus; Babiacetus; Protocetus; Eocetus; Georgiacetus; Carolinacetus; Natchitochia; Basilosaurus; Dorudon; Zygorhiza; Saghacetus; Chrysocetus; and only then do we get to Mysticeti and Odontoceti. Rodhocetus alone doesn't give you a complete picture of the origin of whales; very far from it. I get the distinct impression that you don't understand what you're talking about.
It doesn't. Wanting to believe otherwise doesn't make it otherwise. A hollow balloon isn't a feather.
And it's not even an archosaur... fuck, it's not even in the diapsid crown-group. It's closely related to Weigeltisauridae and maybe Drepanosauridae. The squamates are more closely related to the birds than Longisquama is!
I've been back in Austria for a year now.
Dunning-Kruger effect. Like a creationist, he believes in all seriousness that if he doesn't know something, nobody knows it; and like a creationist, he doesn't even get the idea of actively seeking information.
Hey, Cal, Jinfengopteryx and Anchiornis are troodontids. It's not just that your expectations of the fossil record are deeply naÃ¯ve; it's not just that sister-groups (like deinonychosaurs and birds for instance) must have the same age rather than one being older than the other; we actually have deinonychosaurs that fulfill your silly criterion of being older than Saint Archie, and that's not limited to isolated teeth anymore. (Late and Middle Jurassic teeth that may belong to dromaeosaurids and troodontids have been known for decades, notwithstanding the fact that Feduccia doesn't read the dinosaur literature and you don't read anything that isn't by the BAND; for instance, troodontid, "velociraptorine", and even specifically "dromaeosaurine" teeth occur in the Kimmeridgian site of Guimarota in Portugal. "Dromaeosaurine" teeth are restricted to a subset of Dromaeosaurinae, "velociraptorine" teeth are shared by most other dromaeosaurids including Sinornithosaurus.)
Oh, and, there's a troodontid skeleton from the Morrison Formation that Scott Hartman has been describing for years. He gave a talk about it at the 2007 SVP meeting. Do you know what SVP means?
It is scary that these things used to run around wild. But I look forward to the fact that we can clone things - what ever happened with the woolly mammoth that was going to be cloned?
good evidence - bird digits are I-II-III
Wow! Thanks a lot!!! This looks like a wonderful paper. I'll read it ASAP.