. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Relations of Cracid Genera • Viiillcumier 15 polytypic species; there does not appear to be any overlap in their ranges. They have a rather restricted distribution in central and eastern Brazil, only one fonn (pileato) being actually spatially isolated from the others (Fig. 11). The affinities of jacucaca with the pipilc species-group are obvious, although their proportions are somewhat different, the tar- sus being proportionately shorter in pipilc and cumanensis. In my opinion the iacu- caca species-group, because o
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Relations of Cracid Genera • Viiillcumier 15 polytypic species; there does not appear to be any overlap in their ranges. They have a rather restricted distribution in central and eastern Brazil, only one fonn (pileato) being actually spatially isolated from the others (Fig. 11). The affinities of jacucaca with the pipilc species-group are obvious, although their proportions are somewhat different, the tar- sus being proportionately shorter in pipilc and cumanensis. In my opinion the iacu- caca species-group, because of its resem- blance to both the pipile group and the purpurasccns group, links all these birds and suggests that they are all derived from a common ancestral stock. 3) Piirpiiniscens Species-group The several recognized forms that com- pose this group have been variously con- sidered as four species {purpurascens, jac- quaqii, g^ranti, and ohscura) by Hellmayr and Conover (1942), or only two species {purpumscens and ohscura) by Peters (1934). Although neither classification is really satisfactory, Hellmayr and Conover's is somewhat better in view of the incorrect merging of granti with marail, as was done by Peters. For convenience, Hellmayr and Conover's nomenclature has been adopted in the map (Fig. 12), although I only rec- ognize one species in this complex, as explained below. Difficulties experienced by previous au- thors working with these forms were due in part to their failure to recognize the great amount of individual variation in any one population. Blake (1955), taking this fact into account, concluded correctly that pitr- purascem and jacquaqu are conspecific (this had already been suggested by Du- gand, 1952). In British Guiana, southern Venezuela, and northern Brazil, the fonns granti and orienticola are fully intergrading, as was shown by Conover and Phelps (1946). The same authors pointed out that no intergradation was known to take place between jacquogu an
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