Tim Allwood said:there is still some confusion over limits in cachinnans
Tim Allwood said:Hi Allen
the debate is ongoing
see AERC TAC's taxonomic recommendations of Dec 2003
there was a bit of a ding-dong between chalyrecki (spelling incorrect) and others about taxonomy of Herring Gulls in the 90s
Tim
Tim Allwood said:there is still some confusion over limits in cachinnans
to expand:
some authors (mostly eastern Europeans/Russians) are of the opinion that south eastern Herrings intergrade with cachs in a broad zone...
Tim
Well, I thought that their "Messages from the Rings of Saturn" was out of this world!Tim Allwood said:Yep Allen Heaven Up Here's a great record
was never to keen on a Flock of Seagulls though...
you can get the AERC stuff on the net for free - it's excellent
http://www.aerc.be/aerc_tac.htm
Docmartin said:Actually.. cachinnans DOES intergrade with argentatus, and probably has done, at least sporadically, for a while. It's reasonable to believe that omissus arose from introgression of cachinnans into an eastern population of argentatus, although the published evidence (Helbig and Crochet papers) would suggest that there is little if any evidence of cachinnans mtDNA in argentatus.
sphinx79 said:Without knowing much about the science behind it, the argument that omissus arose from intergradation between eastern argentatus and cachinnans strikes me as fanciful to put it mildly. It's well established nowadays that omissus is merely a variant of argentatus with yellow legs and not a separate form.
sphinx79 said:And you have to ask how on earth Herring Gulls with yellow legs would arise from hybridisation between argentatus and cachinnans, both of which have pink legs...
Greg
sphinx79 said:Yes, cachinnans hybridises with argentatus, as does michahellis but this is to be expected where similar species meet and in any case isn't a bar to species status.
Many more similar species, e.g. Collared/Pied Flycatcher, Carrion/Hooded Crow, to name just a couple, hybridise freely in overlap zones. The thing about cachinnans is that it is so different morphologically from any of the western herring gull types that it's impossible (for me anyway) to imagine it not being a good species.
Without knowing much about the science behind it, the argument that omissus arose from intergradation between eastern argentatus and cachinnans strikes me as fanciful to put it mildly. It's well established nowadays that omissus is merely a variant of argentatus with yellow legs and not a separate form. And you have to ask how on
earth Herring Gulls with yellow legs would arise from hybridisation between argentatus and cachinnans, both of which have pink legs...
Rgds
Greg
Bluetail said:Just a devil's advocate question from someone who doesn't understand genetics, let alone the LWHG complex: Is the mtDNA of omissus distinguishable from argentatus? Is there any chance that omissus could be a good (sub)species that is heading for extinction because of inability to compete with argentatus?