Part S, Echinodermata 1, vol. 1 & 2 , Ch. 4, p. 455 - 565

Abstract

Do advancements in techniques of fossil preparation and discoveries based on new materials or critical new investigations of old contribute to better understanding of relationships that bear on classification and interpretation of phylogeny and evolution?

A probable case of heterochrony in the solutan Dendrocystites Barrande, 1887 (Echinodermata: Blastozoa) from the Upper Ordovician of the Prague Basin (Czech Republic) and a revision of the family Dendrocystitidae Bassler, 1938

“…However, as originally defined by Jaekel (1901), the suborder Soluta was comprising the two families Dendrocystitidae and Rhipidocystidae. As later demonstrated by Hecker (1940), the putative affinities between dendrocystitids and rhipidocystids suggested by Jaekel (1901,1918) were largely based on a chimeric fossil, resulting from the fortuitous association of a solutan homoiostele with thecal fragments belonging to an ophiocistioid (Volchovia) and two eocrinoids (Bockia and Rhipidocystis; see also Ubaghs 1967a, Rozhnov & Jefferies 1996. Consequently, the family Rhipidocystidae was removed from the order Soluta by Hecker (1940), and placed within the class Eocrinoidea by Ubaghs (1960).…”

“…As originally defined by Gill & Caster (1960), the class Homoiostelea and its two subdivisions, the superorders Astylophora (order Soluta) and Stylophora (orders Cornuta and Mitrata) relied mainly on the supposedly similar aspect of the long appendage (stele) in these three groups of "carpoids". However, the homology of all homoiostelean steles was seriously questioned by Ubaghs (1963Ubaghs ( , 1967aUbaghs ( , 1981, who removed the stylophorans from the homoiosteleans, and placed them in a separate class Stylophora. As a consequence, the class Homoiostelea was reduced to the single order Soluta, and the two taxonomic groups homoiosteleans and solutans became coextensive.…”