Strepsirhine dichotomy from a human perspective (Primates: Lorisoidea, Lemuroidea)

Abstract

Using monospecific, polyclonal antisera against 69 human plasma proteins, 128 antigenic determinants from 40 cross-reacting homologues were characterized in representatives of the prosimian genera Lemur, Eulemur, Varecia (Lemuridae) and Otolemur (Galagidae). Seventeen determinants from 16 different proteins were absent in homologues of the gagalo but were shared by lemurs and several platyrrhines, cercopithecids, and hominoids. Smaller locus samples for potto(Perodicticus potto) and slow loris (Nycticebus coucang) confirmed the more distant immunological relationship of lorises than of lemurs to anthropoids. If evolutionary rates are constant and equal in lorisiform and lemuriform prosimians, this patern of character distribution indicates strepsirhine paraphyly, lorises diverging earlier (possibly some 6 times 106 years) than lemurs from anthropoid ancestors. If this is so, lorises rather than true lemurs should be elected to root the polarity of character evolution in Primates. As an alternative, galagine proteins evolve more rapidly than lemurine homologues.