Morphometric studies of Climacograptus (Hall) and the phylogenetic significance of astogeny.

Climacograptus typicails and its varieties are abundant at many horizons in North American Caradoc strata. Morphometric analysis of colony form in C. typicalis and C. pygmaeus reveals low levels of variation for a colony. The analysis of astrogeny and its relationship to colony form suggests that many aspects of overall form are highly correlated with astogeny and that differences in the astogenetic pattern of C. typicalis and C. pygmaeus are correlated with some of the differences in colony form that distinguish the two species. A theoretical framework is needed for the incorporation of astogenetic data into systematic and phylogenetic practice, and a working hypothesis in the formulation of systematic relationships and phylogenesis is proposed.-from Author