Quite cynical comment (with article following) about (still !) heated discussions on a group of
early fish :
http://www.palaeos.com/Vertebrates/Units/040Pteraspidomorphi/040.800.htmlThis is very intereysting, too, if you are interested in early vertebrae history. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
My favourite semntence from that :
With the advent of more contemporary biochemistry and molecular biology, bizarre acronyms ("cAMP-activated Ca-dependent GTPase") and genetic silliness ("Sonic Hedgehog") displaced most of this odd, but dignified, old vocabulary, as well as the odd, but dignified, old professors who had used it.
Halstead and Tarlo are the same person. Tarlo changed his name in 1969 and moved from England (at least for a few years) to the University of Ife in Nigeria. Must be an interesting story there ... .
This general take on the Osteostraci is not disputed, least of all here. The true purpose of this essay, to the extent it has one, is to express frustration with the details of these osteostracan pectoral appendages. They are probably homologous with gnathostome pectorals, but there are problems.
By contrast, chondrichthyans are an unruly mob with few calcified parts. They often wander about aimlessly in pelagic environments, and have repeatedly demonstrated a willful, even blatant, indifference to the legitimate needs of hominid paleontologists.
Indeed, since the Osteostraci seem to have had only two semi-circular canals, it is difficult to see how anything could have been of much help in navigation since the fish evidently lacked the neural wiring to orient themselves well for movement in a three-dimensional medium.
Note: I once described ptyctodonts as looking like an upper class Englishman dressed for dinner. I stand by that description. ATW020329.
<img src="/ubbthreads/images/graemlins/delight.gif" alt="" />
De-construction of the great Brachiosaur fossil ijn the museum in BerlinPlease note that up to approx. 4:45 minutes nothing too interesting seems to happen.
Needs windows media player plugin to work.
