Myth of Reptilian Domination
WHILE EVIDENCE for an unexpected diversity of once large
marsupial carnivores in Australia grows, it is also becoming apparentapparent
that the presumed diversity of former big terrestrial reptiles
has been exaggerated. For example, estimates of maximum
body mass in the giant lizard, Megalania prisca, were extrapolated
from a single toe bone. This case was always flimsy, a fact
that has been further highlighted by a recent revelation from
Ralph Molnar of the Queensland Museum (now retired) that
this bone probably did not belong to M. prisca. More important,
average sizes, not maxima, are the critical numbers in assessing
ecological significance. My estimate for mean body mass
in M. prisca is less than 160 kilograms—still a very big lizardbut far short of the 1,000 kilograms commonly cited. Add the
perspective that M. prisca was much better adapted to a scavenging
role than marsupial lions, ate around 90 percent less per
unit body weight and was less widely distributed, and the argument
for reptilian domination in Australia looks weak.
Similar problems undermine the credibility of the two other
reptiles offered as contenders in the big terrestrial carnivore
stakes: the giant snake Wonambi naracoortensis and the “terrestrial”
crocodile Quinkana fortirostrum. It remains uncertain
that either was actually terrestrial, and if large nonterrestrial
reptiles are brought into the equation, then Australia is no
standout. In modern South America, for instance, eight species
of crocodile and a giant semiaquatic snake commonly take terrestrial
prey.
It is true that Thylacoleo carnifex was smaller than the
biggest of contemporaneous mammalian carnivores elsewhere
in the world. And at least in the Pleistocene, there were fewer
species of large warm-blooded predators in Australia than in
arbitrarily defined regions of similar size in North America or
Africa. But attempts to explain this situation as a product of low
productivity overlook a more obvious difference: Australia is
an island. Fundamental principles of biogeography invalidate
comparisons that do not account for the isolation of the island
continent. Consider South America, which until three million
years ago was also isolated and dominated by marsupial carnivores.
In the two million years preceding species interchange
with North America, no more than three large, truly carnivorous
mammals are known to have existed in South America.
The biggest was the 60-kilogram marsupial sabertooth, Thylacosmilus
atrox. But after formation of the Panama land
bridge, circumstances changed dramatically. There have been
at least 12 large hypercarnivorous mammals in South America
in just the past 65,000 years, some more than five times as heavy
as T. atrox, and all have descended from North American immigrants.
It is difficult to escape the conclusion that isolation
and immigration were the key factors behind this turnaround.
Previous projections of Australia as the island where low productivity
produced a biotically stunted mammalian carnivore
fauna were wrong. Fossil diversity has been underestimated, and
the effects of isolation have not been properly considered.

Это пишет любитель млеков, так что я думаю он принижает достоинства мегалании, которая явно была одним из верховных хищником и с ней явно не желали сталкиваться другие хищники. Но с тилаколео они по моему мнению делили ниши, мегалания думаю была саванновой. А тилаколео жил в лесу или в саванне с еревьями, он хорошо лазил по деревьям.

Ьегалания с черепом 80 см весила бы около 2 тонн. Учитывая что череп комодо в среднем 21 см, а вес в среднем 70 кг.

Ответ в теме про мегаланию.

http://depositfiles.com/files/xnz7c652l - реконструкция Тилаколео с Девианта (прискорбно, не помню, чья).

Виды дипротодонтов: Diprotodon opatim,Diprotodon minor, Diprotodon loderi, Diprotodon annextans.

Скелет и череп современной ехидны!











Представте себе размер вымерших видов ехидн с метровыми костями лап и 65см черепом!
†Zaglossus hacketti
Main article: Zaglossus hacketti

    * Habitat: Western Australia
    * Era: Upper Pleistocene
    * Fossil
    * This species is known only from a few bones. At a metre long, it was huge for an echidna and for monotremes in general.

[edit] †Zaglossus robustus
Main article: Zaglossus robustus

    * Habitat: Tasmania
    * Era: Pleistocene
    * Fossil
    * This species is known from a fossil skull about 65 cm long.

Алекс, но ведь у ехидны 70% длины черепа - это узкая вытянутая морда. Так что даже при длине 65 см зверек не был уж очень крупным.
Zaglossus hacketti - я так понял, что 1 м - это общая длина животного, а не одной кости Интересно, какой высоты в плечах был этот вид. По длине тела сопоставим с мелкой овцой, наверное, но должен был быть гораздо ниже ее. И полностью покрыт иглами, гораздо более страшными, чем у скрытных современных видов - это ведь единственная защита большой ехидны была, больше обороняться от сумчатых львов, тилацинов и варанов-то было нечем.

Австралийская мегафауна - http://paleopedia.free.fr/marsupiaux_cl … ation.html

Ерунда это. Вараны совершенно не так двигаются и охотятся. Чтобы это понять, достаточно посмотреть на кадры охоты современного аналога мегалании - комодского варана.

      http://shop.auspost.com.au/assets/docum … _notes.pdf

FAUNA of AUSTRALIA
VOMBATIDAE
R. T. WELLS
http://www.environment.gov.au/biodivers … 32-ind.pdf



Megafauna demography and late Quaternary climatic change in Australia: A predisposition to extinction
Steve Webb
http://epublications.bond.edu.au/cgi/vi … t=hss_pubs


PRELIMINARY NOTES ON PHASCOLONUS GIGAS, OWEN [PHASCOLOMYS (PHASCOLONUS) GIGAS, OWEN], AND ITS IDENTITY WITH SCEPARNODON RAMSAYI, OWEN.
BY E. C. STIRLING, M.D., F.R.S, C.M.Z.S. AND A. H. C. ZIETZ, F.L.S., C.M.Z.S.
http://www.samuseum.sa.gov.au/Journals/ … 23p135.pdf

Еl Padre :

http://savepic.org/1384258.jpg

Так, теперь надо её достать в большом формате))))