Morphology and morphometry of two hybridizing buntings at their hybrid zone in northern Iran reveal intermediate and transgressive morphotypes

The closely related Black-headed Bunting(Emberiza melanocephala,a western Palearctic lineage)and Red-headed Bunting(Emberiza bruniceps,an eastern Palearctic lineage)hybridize and replace each other south of the Caspian Sea.The parental species have distinct phenotypes and therefore morphology is useful for assessing hybridization in the contact zone.In the years of 1940 and 1977,quite a few hybrids were collected and studied morphologically.Since then,the hybrid zone appears to have expanded westwards,but there has been a time gap in the collection of morphological data.Here we reanalyze bunting specimens morphologically and compare the historical data with recent data.Morphometric and phenotypic traits from three time periods(1940,1977 and recent)were studied to assess phenotypic variation of hybrids,pattern of hybridization,and transgressive traits in the hybrid zone.Our results show that most of the birds in the hybrid zone exhibit intermediate phenotypes(both colors and morphometric characters),ranging from the pure phenotype of either of the parental species.However,hybridization has also produced novel phenotypes not seen in any of the parents.Using a canonical discriminant function analysis,the morphometric characters separated each parental species and the hybrids quite well.Our results showed morphometric intermediacy of hybrids in accordance with phenotypes.We observe a time trend in which recent hybrids are more similar to Red-headed Buntings phenotypically compared to historical samples.This pattern is likely a signature of a westward expansion of the Red-headed Bunting into the breeding range of the Black-headed Bunting.

The rediscovery of Strix butleri(Hume,1878)in Oman and Iran,with molecular resolution of the identity of Strix omanensis Robb,van den Berg and Constantine,2013

Background:Many species of owls(Strigidae) represent cryptic species and their taxonomic study is in flux.In recent years,two new species of owls of the genus Strix have been described from the Middle East by different research teams.It has been suggested that one of these species,S.omanensis,is not a valid species but taxonomic compari?sons have been hampered by the lack of voucher specimens of S.omanensis,and the poor state of the holotype of S.butleri.Methods:Here we use new DNA sequence data to clarify the taxonomy and nomenclature of the S.butleri complex.We also report the capture of a single S.butleri sensu stricto in Mashhad,Iran.Results:A cytochrome b sequence of S.omanensis was found to be identical to that of the holotype of S.butleri,indicating that the name S.omanensis is best regarded as a junior synonym of S.butleri.The identity of the S.butleri captured in Mashhad,Iran,was confirmed using DNA sequence data.This represents a major(1300 km) range exten?sion of this species.Conclusions:The population discovered in Oman in 2013 and originally named ‘S.omanensis' actually represents the rediscovery of S.butleri,which was known from a single specimen and had not been recorded since 1878.The range of S.butleri extends into northeast Iran.Our study augments the body of evidence for the recognition of S.butleri and S.hadorami as separate species and highlights the importance of using multiple evidence to study cryptic owl species.