75/125 YEARS

A Phylogenetic Analysis of Encrusting Hydrocorals from the West Coast of North America

LINDSTROM, Kirsten S., Museum of Paleontology and Dept. of Integrative Biology, Univ. of California, Berkeley, CA 94720-4780

Hydrocoral species in the genus Stylantheca have traditionally been separated into a northern (S. petrograpta) and a southern (S. porphyra) species based on three characters examined only from the type specimens. This study examined these characters in colonies from populations along the west coast of North America. Statistical analyses indicated that the characters historically used to separate S. petrograpta and S. porphyra are not correlated as suggested by Cairns (1983), and are thus considered independent. A phylogenetic analysis was used to examine relationships among populations using both morphological and allozyme characters, however, the allozyme characters were uninformative. Although support for the tree is weak (decay index = 1), the hypothesis of a northern and southern lineage is not falsified. In addition, the morphological variation does not appear to be correlated with substrate type. However, because the characters used in the analysis have not been established as heritable, it is suggested that the addition of molecular characters may be useful for clarifying relationships.

75/125 YEARS