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Re: Various subjects



David Marjanovic wrote:

<How can someone dinosaur-size possibly survive the
Chicxulub impact (and the possible Shiva impact, which
?was even closer)?>

  Assumption here is that dinosaurs were particularly
big, as there are known Maastrichtian badger-size
mammals from North America and some latest K dinosaurs
were quite small, though maybe not too small. A great
deal of large-size forms survived the KT event,
including turtles and crocs.

<"Suppose that a river/lake-living dinosaur evolved in
the Late Cretaceous of Africa [...]" Rather
impossible; this niche was held by crocodiles (and a
few freshwater plesiosaurs and hesperornithiforms).>

  Dinosaurs out compete dinosaurs ... new paper. At
least, that would be a working title if
hesperornithiforms were used. They are rather concise
forms, incidentally, and highly-specialized form are
slow to change and thus in broad-band extincting
event, they seem to be the ones that would go _poof!_
first. Animals good at adapting (reptiles, generalized
mammals, birds) would survive. Avian dinosaurs that
respecialized into large predatory terrestrial forms
(as in some phorosrhacids) wouldn't be too difficult
to play with.

<How do you reliably keep the dinos in and modern
animals like vultures out for 65 ma? Besides,
terrestrial pure carrion eaters are probably
impossible (as stated in every discussion on T. rex).
Any carrion eaters there will certainly be the
vultures common in the surroundings.>

  Point: Pure carrion feeders (drop the "terrestrial"
adjective) are not known. All primary
scavengers/carrion feeders have been known to take
live prey, but those that are specialized to carrion
(griffons, hyenas, raccoons(?)) typically scavenge.
This is essentially Currie's rebuttal to Horner's
hypothesis. There are no known _strict_
"carrionovores." Scavengers actually have the best of
both worlds! :)

<- No Mongolian dinosaurs, meaning ABSOLUTELY NO
TYRANNOSAUROIDS, no ceratopsids,>

  None of the latter in Mongolia anyway, both in North
America with some evidence for periodic landbridges
between North American and Eurasia (the European side)
persisting into the later K.

<Dromaeosaurs are possible, since they were around in
Sudan (but not Velociraptor in person!),>

  What makes you think it isn't *Velociraptor*? It is
a velociraptorine, and this forms are so close that
convergence has been noted in some forms (read papers
by Currie on the Judithian Vel teeth, Paul has noted
possible lumping of all velociraptorine genera into
Vel, and that would quite interesting, no?).

<troodontids are probably not (Troodon has been
reported from Argentina, as far as I know,>

  A "troodontid" has been reported. That's all.

<but that was after Africa split off. Maybe Africa was
still connected to India and India via Kerguélen to
Antarctica. Same holds for hadrosaurs.).>

  Loosing sight of the supposed troodontid and
dromaeosaurid European material (*Wyleyia,*
*Ornithodesmus,* *Bradycneme,* *Elopteryx,*
*Heptasteornis,* etc.)....

<Why reevolve spinosaurs from allosauroids when there
plenty of spinosaurs in Africa?>

  Because sometimes people like to play with
evolution. Dr. Moreau for example :) In certain
conditions, piscivory will force certain adaptations,
as noted in several Buffetaut papers, Sereno et al.,
1998 and Holtz' 1998 perspective of that last
paper.... Take an odd animal, and hypothetically, in
the right situation, it will evolve or not towards the
easiest route.

<- Probably abelisaurids were around (there is only
negative evidence, though, except those
"Majungasaurus" scraps from Egypt).>

  *Tarascosaurus* from the later K in France, various
abelisaurid material in India, Madagascar, Egypt,
Tunisia, Ethiopia?, Morocco, Algeria?, Niger?, etc.

<- Juveniles and adults filling different niches is
only possible if the young are very, very precocial
(and grow rather slowly) -- not probable for
dinosaurs.>

  Quantify this statement. Most reptile young are
precoccial. Precoccial birds do not tend to vary their
diet from mother's. Precoccial mammals are
lactic-dependant, and this can be held in support of a
varied diet between young and adult.

<There are even people around believing
Terrestrisuchus was arboreal (or that something
similar might have become).>

  There are arboreal varanids, in which small goannas
and young larger forms will take to the trees for
protection from bigger or older forms (*V. kmodoensis*
does this, too).

<Why are Crocodylus and all taxon names derived from
that (-inae, -idae, -iformes, -omorpha, -otarsi...)
always written with y? It's krokodeilos in Greek and
(therefore) crocodilus in Latin (I've checked the
dictionary to be sure).>

  Because Crocodylia won by default of prevalent usage
against Crocodilia. Sometimes, roots be damned.

=====
Jaime "James" A. Headden

  Dinosaurs are horrible, terrible creatures! Even the
  fluffy ones, the snuggle-up-at-night-with ones. You think
  they're fun and sweet, but watch out for that stray tail
  spike! Down, gaston, down, boy! No, not on top of Momma!

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