5 posts • Page 1 of 1 [Administrators: feel free to relocate
this post at your discretion; with its zoogeographical focus, it
could just as aptly lie within the "Evolution" forum.] Looking
to this map of global crayfish distribution, one is immediately
struck by what are seemingly several discrepancies - namely, the
complete absence of crayfish from a broad pan-tropical belt
encompassing most of South America, continental Africa (but not
Madagascar) in its entirety, South/Southeast Asia, and
[naturally] most of the Indo-Pacific. Based on fossilized
remains, it seems likely that crayfish arose in the far-southern
reaches of Permian Pangea: As the following quotes reveal, said
peculiarity has been considered before, but little of substance
has come from this basal speculation: (My italics and bracketed
commentary; scientific names are not necessarily contemporarily
valid.) From Chapter Six ("The Distribution and the Ætiology of
the Crayfishes") of T.H. Huxley's The Crayfish. As Huxley wrote,
prawns of the genus