Mixing the waters: a linear hybrid zone between two riverine Neotropical cardinals (Paroaria baeri and P. gularis)

ARETA JI; KIRWAN G; DORNAS T; ARAUJO-SILVA L; ALEIXO A

EMU

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2017 vol. 117 p. 40 - 50

0158-4197

<!-- /* Font Definitions */@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-520092929 1073786111 9 0 415 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin-top:0in;margin-right:0in;margin-bottom:10.0pt;margin-left:0in;line-height:115%;mso-pagination:widow-orphan;text-autospace:none;font-size:11.0pt;font-family:Calibri;mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:Calibri;mso-fareast-language:EN-GB;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:10.0pt;mso-ansi-font-size:10.0pt;mso-bidi-font-size:10.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;}@page WordSection1{size:8.5in 11.0in;margin:1.0in 1.25in 1.0in 1.25in;mso-header-margin:.5in;mso-footer-margin:.5in;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->Amazonian rivers have been more frequently conceptualizedas barriers, rather than as habitats for birds with their own ecological andbiogeographic histories. However, many river-restrictedbird species have differentiated within the formidable network formed by theAmazon and its tributaries. Here we demonstrate that theriverine-distributed Crimson-fronted Cardinal (Paroaria baeri) is narrowly distributed along the middle RioAraguaia basin, where it comes into contact and hybridizes with thegeographically widespread Red-capped Cardinal (P. gularis). This one-dimensional hybrid zone, which is situatedover c. 160 km along the Araguaia andJavaés rivers, appears to be of recent origin. Admixed individuals between thenon-sister P. baeri and P. gularis are phenotypically intermediatebetween the parental species, and superficially resemble the geographically disjunctand phylogenetically distant Masked Cardinal (P. nigrogenis). Two phenotypically admixed specimens were confirmedas such based on sequences of the mitochondrial Cyt-b and the Z-linked MUSK gene.Field observations and genetic data indicate that P. baeri × P. gularis hybrids are capable of producing viable offspring, but more data are necessary to confirm hybrid viability and fertility. The non-sister hybridizingspecies P. baeri and P. gularis last shared a common ancestor 1.8?2.8 mya ago (uncorrected geneticp-distance of 4%), which corresponds closely to when the Araguaia/Tocantins river basinlast discharged directly into the Amazon