[Taxacom] Examples for Eurasian-Australian distribution
kennethkinman at webtv.net
Thu Jul 22 13:29:52 CDT 2010
Last night I surmised that the relic distribution of Hygrobia was
probably due to competition or habitat loss. I am now leaning more
towards competition, specifically with members of Family Dytiscidae
(apparently its sister group).
Dytiscidae is a relatively large family and probably outcompeted
related families (such as Hygrobiidae and Amphizoidae). So I would
hypothesize that Hygrobiids escaped total extinction by surviving in
marginal habitats that most Dytiscids perhaps don't tolerate very well
(particularly stagnant water that is acidic). Amphizoidae also has a
relic distribution and may have survived in a similar manner.
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