Aegithalidae (1 Viewer)

[Jim LeNomenclatoriste]

Robert M. Zink, Garth M. Spellman, Ricardo Canales-del-Castillo, Kevin Epperly, and John Klicka (2023) Mitochondrial DNA phylogeography of the Bushtit (Psaltriparus minimus). Wilson Journal of Ornithology 135: 22-30.

Abstract
We sequenced the mitochondrial ND2 gene for 290 Bushtits (Psaltriparus minimus) sampled from northern Washington to Guatemala. Phylogenetic analysis sorted specimens into 2 main lineages residing either west (coastal) or east (inland) of the Sierra Nevada and Cascades. These lineages are separated by 3.5% sequence divergence and correspond with the distributions of 2 long-recognized phenotype groupings (brown-capped and plumbeous, respectively). Three additional monophyletic geographically structured lineages were identified. Birds from southmost Baja California (Sierra de la Laguna) segregate from other coastal samples whereas the inland lineage includes additional lineages occurring in southeastern Mexico (Morelos, Puebla, Guerrero, and Oaxaca) plus Guatemala, and southwestern Mexico (Michoacán). Examination of museum specimens revealed that a black-eared phenotype occurs sporadically in the interior lineage in southern U.S. and northern Mexico, increasing in frequency to the south, corresponding roughly with these southern Mexican mtDNA lineages. Degree of sequence divergence between the 2 main lineages suggests a relatively early divergence, and ample time for 2-way introgression to occur. However, only 1 of our sampling localities (Lake Co., Oregon; n = 4) was mixed for coastal (n = 1) and interior (n = 3) lineages suggesting the possibility of reproductive isolation between the 2 main lineages.

Does this imply two potential species?

 

[Tom Schulenberg]

Does this imply two potential species?

from the paper:

"Future work
Our study involved a single mtDNA gene tree, which many authors suggest is insufficient for inferring aspects of evolutionary history or making taxonomic recommendations (Edwards et al. 2005). Yet, in some cases, mtDNA and nextgen analyses suggest congruent evolutionary histories (Manthey et al. 2021, Vázquez-Miranda et al. 2022). We suggest that the mtDNA gene tree provides salient points for further analysis. For example, the 5 mtDNA lineages provide hypotheses for testing with multi-locus data sets. More finely spaced samples would clarify the distribution of coastal and inland haplotypes and reveal if there are other areas where the coastal and interior lineages co-occur. It will be important to confirm the population history inferred from the mismatch distributions with multi-locus data".

in other words, "more research required".

 

[Jim LeNomenclatoriste]

in other words, "more research required".

Ok.

 

[Mysticete]

I wouldn't expect movement on this without nuclear DNA and a examination of the hybrid zones, at minimal.of the World suggests the two populations come into contact, or at least get close to one another.