Karyotypic analysis of seven species of Tyrant Flycatchers (Tyrannidae)

Abstract

Seven species of Tyrannidae from NE Argentina were cytogenetically studied. The chromosome number and basic morphology of Myiarchus ferox (2n=76), Tyrannus savana (2n=78), and Elaenia parvirostris (2n=78) are described for the first time, while Pitangus sulphuratus (2n=78), Tyrannus melancholicus (2n=78), Platyrinchus mystaceus (2n=60) and Cnemotriccus fuscatus (2n=84) are re-analyzed. The adult specimens were captured with mist nets and chromosome preparations were stained from embryonic cells and bone marrow. P. mystaceus presents a low diploid number for its class (2n=60) with predominance of biarmed chromosomes. M. ferox has a W chromosome proportionally bigger than usual for Passeriformes. T. savana and T. melancholicus show differences only at the second chromosomic pair and at Z chromosome. A discrepancy with previous data is shown for P. sulphuratus (2n= 78) versus the previous report (2n=68).