Re: On predation.
chris brochu (gator@mail.utexas.edu)
7 Nov 1995 02:07:40 GMT
In article <hubey.815092948@pegasus.montclair.edu> H. M. Hubey,
hubey@pegasus.montclair.edu writes:
>>Miocene, they must have used transoceanic routes for dispersal. There is
>>no other way to explain their presence in South America, Africa, and
>>Australia.
>
>The case for Ausralia is believable because aborigines did
>something similar. It's hard for me to believe crocs swimming
>across the Atlantic. If it wasn't a freak accident of some
>croc surviving for a year or so while the current drifted it over,
>it's hard to see how else it could have happened.
This "freak accident" is KNOWN to have happened multiple times in the
Cenozoic. To whit:
1. Living species of Crocodylus had diverged by the Pliocene, but not
before the Miocene. The Nile crocodile is more closely related to New
World Crocodylus (C. acutus, C. moreletii, C. intermedius, C. rhombifer)
than it is to the Indopacific radiation, including the saltwater croc (C.
porosus) and a wide range of other species. There is no other way for
this taxon to have spread from Africa to the western hemisphere without
invoking transoceanic crossing.
2. Gavialoids today occur only in India, but they are known from Africa
and South America during the Oligocene. They are never found in North
America. They must have crossed oceanically.
3. An insular relative of the dwarf crocodile, Osteolaemus, existed in
Madagascar during the Quaternary. The Mozambique Strait was a wide
stretch of seawater for most of that time.
4. Croc bones are also known from Aldabra Atoll and the Seychelles. No
land bridges ever existed between these islands and any mainland.
chris
>
|