The Echinoid Directory

Phylogeny and classification


Characters and data matrix supporting this cladogram

The classification followed here is slightly modified from Smith & Wright (1990).

Order Echinothurioida Claus, 1880

Stem group
Family Pelanechinidae Groom, 1887
Genus Pelanechinus Keeping, 1878

Crown group
Genus Paraphormosoma Mortensen, 1934
Family Kamtosomatidae Mortensen, 1934
Genus Kamptosoma Mortensen, 1903
Family Phormosomatidae Mortensen, 1934
Genus Phormosoma Wyville Thompson, 1872
Genus Hemiphormosoma Mortensen, 1934
Family Echinothuriidae Wyville Thompson, 1872
Subfamily Hygrosomatinae Smith & Wright, 1990
Genus Hygrosoma Mortensen, 1903
Subfamily Sperosomatinae nov. Smith & Wright, 1990
Genus Sperosoma Koehler, 1897
Genus Tromikosoma Mortensen, 1903
Subfamily Echinothuriinae Wyville Thompson, 1872
Genus Echinothuria Wyville Thompson, 1872
Genus Hapalosoma Mortensen, 1903
Genus Asthenosoma Grube, 1868
Genus Araeosoma Mortensen, 1903
Genus Calveriosoma Mortensen, 1934

A more recent phylogenetic analysis of this group is given in Mooi et al. (2004). This provides an in-depth analysis of species relationships. There are several differences with the above cladogram, most notably in placing Kamptosoma within the Phormosomatidae and in placing Hygrosoma as sister group to Echinothuriinae rather than as sister group to Spermosomatinae.

Mooi, R., Constable, H., Lockhart, S. & Pearse, J. 2004. Echinothurioid phylogeny and the phylogenetic significance of Kamptosoma (Echinoidea: Echinodermata). Deep Sea Research II 51, 1903-1919.

Smith, A. B. & Wright, C. W. 1990. British Cretaceous echinoids. Part 2. Echinothurioida, Diadematoida and Stirodonta. Monograph of the Palaeontographical Society London, 101-198 (publication number 583, part of volume 143 for 1989).

Kroh, A. & Smith, A. B. 2010. The phylogeny and classification of post-Palaeozoic echinoids. Journal of Systematic Palaeontology 8, 147-212.