ABSTRACT
While biochemical techniques and DNA analysis may be used in addition to morphological characters for analysis of living echinoderms, these tools cannot be extended to fossils. Skeletal matrix proteins, however, may be trapped and preserved for millions of years in fossil genera, thus allowing extinct taxa to be phylogenetically analyzed with extant taxa.
The 83kDa skeletal matrix proteins of several extant genera including Mellita,Echinarachnius and Arachnoïdes were analyzed using reverse phase liquid chromatography and amino acid composition analysis. The amino acid composition of this protein in all genera was similar with high percentages of aspartic acid and asparagine, glutamic acid and glutamine, and glycine as is typical of matrix proteins in other phyla.
