Genetic Evidence Conclusively Proves Italian Sparrow Is Its Own Species
Norwegian scientists have done DNA research that clearly defines the Italian Sparrow as a uniques species. It is a cross between the House Sparrow and Spanish Sparrow.
Some field guides, including Birds of Europe by Killian Mullarney and Dan Zetterstrom (the one I currently use for Europe), have already identified the Italian Sparrow/Passer italiae as its own species.
Learn more at:
BBC Italian sparrow joins family as a new species
Molecular Ecology Hybrid speciation in sparrows I: phenotypic intermediacy, genetic admixture and Barriers to Gene Flow
Natural History Wanderings 
This is really interesting.
“Homoploid hybrid speciation is thought to require unusual circumstances to yield reproductive isolation from the parental species, and few examples are known from nature”
“Further, the Italian sparrow possesses mitochondrial (mt) DNA haplotypes identical to both putative parental species”
This reminds me of issues like the Red Wolf of the southeast and parthenogenic all female Whiptail lizard populations in the southwest. Apparently the mitochondrial DNA (a direct maternal inheritance) of the Red Wolf is all either Coyote or Wolf. But the Red Wolf has been a separate species for quite a while (at one time with 3 geographic races).
Apparently when lizards hybridize they tend to produce all female parthenogenic lines. As I understand it, a haploid female egg doubles to diploid without the benefit of fertilization. So you get a diploid female clone. The New Mexico Whiptail is one such.
http://en.wikipedia.org/wiki/Parthenogenesis
Now it appears, the creation of a new lizard species has been done in the lab:
http://www.wired.com/wiredscience/2011/05/all-female-lizards/
Since the lizards are parthenogenic, there is no issue of back-crossing with parent species. But the Italian Sparrow is interesting. I guess the hybrid sparrows prefer each other as mates strongly enough that their gene pool went off on it’s own, without mixing back.
I did some more reading: It seems that hybrid butterflies can attain instant isolation since their color pattern is intermediate. This intermediate pattern is attractive only to other hybrids and not to either parent species.
http://news.nationalgeographic.com/news/2006/06/060614-butterfly.html
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By: Rusty Scalf on September 20, 2011
at 8:38 AM
Rusty,
Thanks for your most informative comments.
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By: Sandy Steinman on September 20, 2011
at 9:09 AM