Mj. Braun et Rt. Brumfield, ENIGMATIC PHYLOGENY OF SKUAS - AN ALTERNATIVE HYPOTHESIS, Proceedings - Royal Society. Biological Sciences, 265(1400), 1998, pp. 995-999
Last year, Cohen et al. presented molecular data suggesting the surpri
sing result that both currently recognized genera of skuas, Stercorari
us and Catharacta (Aves: Stercorariidae), are not monophyletic. Howeve
r, the most enigmatic conclusion from their analysis, that S. pomarinu
s is sister to C. skua, rests solely on mtDNA sequence data. When the
mtDNA data are analysed in a maximum likelihood framework that account
s for variation in evolutionary rates, Catharacta monophyly cannot be
rejected. None of the best trees that can be derived from two nuclear
data sets of Cohen et al. support the controversial pomarinus-C. skua
node. We propose an alternative hypothesis, that pomarinus is sister t
o a monophyletic Catharacta, as the best explanation of the available
molecular, morphological, and behavioural evidence.