GSP ON DIXON (AGAIN)

[darren.naish@port.ac.uk]

A fleet, armless tyrannosaurid with enhanced stereoscopic vision 
chases a broad-muzzled, spike-crested grazing lambeosaur across a late 
Cainozoic plain. Giant, sexually dimorphic protoceratopians with 
enlarged nasal horns flee in the background while rodents and 
ruminating small ornithopods scurry among burrows and spoil heaps. 
Geese fly overhead.

At long last, courtesy of a friend (I do not mention your name in case 
you get swamped with requests for photocopies), I have Greg Paul's 
1990 review of Dougal Dixon's _The New Dinosaurs_ (_TND_ from 
hereon). The full ref for the review is - - 

Paul, G. S. 1990. An improbable view of Tertiary dinosaurs. 
_Evolutionary Theory_ 9: 309-315.

Because so few people have read or even seen this review, and because 
so many would like to, I here provide a recap. Basically, Greg is very 
critical of Dougal's book and takes him to pieces for three major 
reasons; (1) Dougal's view of the morphology, life appearance, biology 
and behaviour of fossil dinosaurs is clearly not accurrate, as shown by 
the fact that the megalosaurs, pachycephalosaurs and sauropods from 
_TND_ look like restorations from the 1950's and are often 
amorphous and lack the specialised details now known for these 
animals (e.g., scalation patterns, broad bellies and tail bases on 
pachycephalosaurs); (2) Many of the animals in _TND_ are 
biologically or evolutionarily implausible - pterosaurs would not have 
evolved into rodent-headed flightless kiwis, for example, nor into 
archosaurian giraffes, likewise snake-like burrowing or arboreal 
theropods, fully aquatic dugong-like ornithopods and the cadaver-
mimicking 'springe' are, in GSP's view, beyond the realms of things 
that might really have evolved (he draws heavily on the idea that taxa 
are constrained by their biology and the limits imposed upon them by 
their genetics and ecology are not boundless); (3) In _TND_, archosaur 
evolution in the Cainozoic has run riot and a million things that never 
happened in the Mesozoic have now occurred, e.g., flightlessness in 
pterosaurs, aquatic adaptations in ornithopods, arboreality and 
burrowing in theropods etc. Greg argues that a lot of dinosaur 
evolution was surprisingly conservative - some Cretaceous bipedal 
ornithischians are not all that different from Triassic ones, for example 
- and that many Recent dinosaurs would therefore not look that 
disimilar to Cretaceous ones.

Importantly, while Dougal invented diminutive dinosaurs and 
pterosaurs that filled the roles of modern small mammals, birds, 
squamates and other taxa, Greg argues that many of these roles, even in 
a dinosaur-dominated world, would still be filled by the same animals. 
Had non-avian dinosaurs survived to the present, the world would still 
be filled with tree frogs, flamingos, small mammals, lizards and 
snakes, rather than dinosaurian equivalents. Indeed, Greg is not shy to 
suggest that mammals may have done pretty well, even in a dinosaur-
dominated world, and big forms may have evolved on some continents 
(shades of Tertiary South America - i.e. Cainozoic giant dinosaurs 
(phorusrhacoids) contemporaneous with giant mammals) and 
environments. Greg points out that, because early members of some 
key mammalian clades were already around in the Cretaceous 
(including ungulatomorphs, primatomorphs and probable carnivoran 
ancestors), modern-type mammals including large ungulates and 
hominids might still have evolved (hence that episode of 'Sliders':)). 
Greg speculates that, had this occurred, dinosaurs may have competed 
by, for example, growing bigger brains (he notes that some extant 
chondrichthyans have brains comparable to those of some mammals).

Greg also takes Dougal to task for following a fairly predictable 
theme: Dougal appears to have taken living or recently extinct 
mammals or birds, and then tried to shoehorn a dinosaur or pterosaur 
into the same kind of lifestyle/appearance. Thus, in Australia of 
_TND_, there are dinosaurs that look suspiciously like koalas and 
kangaroos, Africa has giraffe-mimicking pterosaurs, and in South 
America there is a glyptodont-lookalike sauropod and a 
_Thylacosmilus_-like theropod. To quote GSP "The evolutionary odds 
against such likenesses in place and form are at best very long; at 
worst, they are anatomically impossible" (p. 313).

Finally, there is a very interesting postscript. Greg's review was 
evidently published at about the time (oh, the irony) that reviews of 
Greg's own book, _PDOTW_, were appearing. Many people were 
quite nasty about _PDOTW_, and 'Having been the recipient of what I 
believe are two or three unjustifiably harsh reviews ... a few additional 
comments are appropriate'. Greg congratulates Dougal on coming up 
with a thought-provoking, controversial and stimulating work that 
clearly took up a lot of time. There is then a fantastic piece of GSP art, 
a description of which opened this text.

Sincere apologies to GSP for trawling over what must seem like 
ancient history. 

Because this review is so hard to get of, I will send copies to people 
that want them BUT, sorry, not for free: I have enough to do as it is 
and will only send if you can do a swap and give me something I 
haven't got in return.

"You and me baby ain't nothing but mammals"


DARREN NAISH 
PALAEOBIOLOGY RESEARCH GROUP
School of Earth, Environmental & Physical Sciences
UNIVERSITY OF PORTSMOUTH
Burnaby Building
Burnaby Road                           email: darren.naish@port.ac.uk
Portsmouth UK                          tel: 01703 446718
P01 3QL                               [COMING SOON: 
http://www.naish-zoology.com]