The Echinoid Directory

Phylogeny and classification of the Cidaroida

Cidaroids have a relatively conservative test morphology and their taxonomy has proved difficult. Mortensen (1903, 1928) based his taxonomy on fine details of spine and pedicellarial morphology, which unfortunately are rarely preserved in fossil taxa. His taxonomy was widely criticized for being oversplit (e.g. Clark 1909, Philip 1964) but formed the basis for the Treatise on Invertebrate Paleontology classification. Numerous fossil genera have been created since then but the only large cladistic analysis of the group to date is that of Smith & Wright (1989). Here the scheme of Kroh & Smith (2010) is followed.

Any taxonomic framework for cidaroids needs to start with the extant taxa. Many fossils are too poorly known to be classified with certainty and can only be included tentatively. The following taxonomic scheme is used here.

Order Cidaroida Claus, 1880

Stem group Cidaroida
Family Triadotiaridae Hagdorn, 1995
Family Serpianotiaridae Hagdorn, 1995
Family Miocidaridae Durham & Melville, 1957
Family Rhabdocidaridae Lambert, 1900
Family Diplocidaridae Gregory, 1900
Family Polycidaridae Vadet, 1988

Crown group Cidaroida
Superfamily Histocidaridea Kroh & Smith, 2011
Family Histocidaridae Lambert, 1900
Superfamily Cidaridea Kroh & Smith, 2011
Family Ctenocidarinae Mortensen, 1928
Family Psychocidaridae Ikeda, 1936
Family Cidaridae Gray, 1825
Subfamily Cidarinae Mortensen, 1928
Subfamily Stereocidarinae Lambert, 1900
Subfamily Goniocidarinae Mortensen, 1928
Some of these are almost certain to prove paraphyletic (e.g. Polycidaridae). For an alternative classification of just Jurassic taxa see Vadet (1991, 2004).

Clark, H. L. 1909. The Cidaridae. Bulletin of the Museum of Comparative Zoology at Harvard College 51(7), 165-230, pls 1-11.

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

Mortensen, T. 1928. A monograph of the Echinoidea. 1, Cidaroidea. C. A. Reitzel, Copenhagen.

Philip, G. M. 1964. The Tertiary echinoids of South-East Australia. Proceedings of the Royal Society of Victoria 77, 433-477, pls 58-67.
Smith, A. B. & Wright, C. W. 1989. British Cretaceous echinoids. Part 1, General introduction and Cidaroida. Monograph of the Palaeontographical Society [publication no. 578, issued as part of volume 141] p. 1-101, pls 1-32.
Vadet, A. 1991. Revision des "Cidaris" du Lias et du Dogger Europeens. Memoires de la Societe academique du Boulonnais 10, 1-176.
Vadet, A. 2004. Echinides fossiles du Boulonnais du Bajocien au Tithonien. Annales de la Societe d'Histoire Naturelle du Boulonnais 3 (2), 1-35.