Cidaroida

Fossil of Stereocidaris sceptifera, photographed by Keith Little.

Belongs within: Echinoidea.
Contains: Archaeocidaris, Cidarinae, Histocidarinae, Rhabdocidarinae, Goniocidarinae, Ctenocidarinae.

The Cidaroida are a group of echinoids with relatively narrow ambulacra and without gill slits. They include the only living echinoids ancestrally without external gills, and with a fossil record going back to the Upper Silurian, they pre-date most other living echinoid groups. Cidaroids commonly have modified spines that may be flared or expanded. The earliest cidaroids are placed in the Archaeocidaridae, which survived to the Permian; members of this family had a flexible test with four or more columns of plates in each interambulacrum. Living species are included in the families Cidaridae and Psychocidaridae, with the former having the primary tubercles on the test perforate and the latter having them imperforate (Fell 1966).

Characters (from Fell 1966): Test subspherical, radially symmetrical, rigid or with imbricating plates; base resorbed during growth. Ambs of two columns; each plate with a single pore pair, not uniting in compound plates, though grouped in diads or triads in some. Interambs conspicuously wider than ambs, of two or more columns; each interamb plate with one enlarged primary tubercle, carrying an enlarged corticate (rarely decorticate) primary spine; areole conspicuous, usually defined by scrobicular ring of secondary tubercles. Lantern present; teeth not keeled. Peristome covered (in life) by imbricating plates; no gills or gill slits. Apical system enclosing periproct. No spheridia. Pedicellariae of two types: globifeorus, with a median venom cell, and tridentate (usually lacking).

<==Cidaroida [Cidaroidea]
    |  i. s.: Lanternarius Regnéll 1956 F66
    |           `--*L. latens Regnéll 1956 F66
    |--Diplocidaridae F66
    |    |--Tetracidaris Cotteau 1872 F66
    |    |    `--*T. reynesi Cotteau 1872 F66
    |    `--Diplocidaris Desor 1855 [=Alternocidaris Quenstedt 1873; incl. Diplotiaris Quenstedt 1872] F66
    |         |--*D. gigantea [=Cidaris gigantea, *Alternocidaris gigantea] F66
    |         |--D. etalloni F66
    |         `--D. miranda F66
    |--Archaeocidaridae B01
    |    |--Archaeocidaris B01
    |    |--Lepidocidaris Meek & Worthen 1873 F66
    |    |    `--*L. squamosa Meek & Worthen 1873 F66
    |    |--Nortonechinus Thomas 1920 F66
    |    |    `--*N. welleri Thomas 1920 F66
    |    |--Polytaxicidaris Kier 1958 F66
    |    |    `--*P. dyeri Kier 1958 F66
    |    |--Silurocidaris Regnéll 1956 F66
    |    |    `--*S. clavata Regnéll 1956 F66
    |    `--Xenocidaris Schultze 1866 F66
    |         `--*X. clavigera Schultze 1866 F66
    |--Psychocidaridae F66
    |    |--Psychocidaris Ikeda 1935 F66
    |    |    `--*P. ohshimai Ikeda 1935 F66
    |    |--Anisocidaris Thiéry 1928 F66
    |    |    `--*A. bajocensis (Cotteau 1880) [=Cidaris bajocensis] F66
    |    |--Caenocidaris Thiéry 1928 F66
    |    |    `--*C. cucumifera [=Cidaris cucumifera] F66
    |    |--Merocidaris Thiéry 1928 F66
    |    |    `--*M. honorinae (Cotteau 1880) [=Cidaris honorinae] F66
    |    |--Sardocidaris Lambert 1907 F66
    |    |    `--*S. piae Lambert 1907 F66
    |    `--Tylocidaris Pomel 1838 F66
    |         |--*T. clavigera (König 1820) [=Cidaris clavigera] F66
    |         `--T. walcotti F66
    |--Miocidaridae [Streptocidaridae, Streptocidarinae] F66
    |    |--Aplocidaris Lambert & Thiéry 1909 F66
    |    |    `--*A. helenae (de Regny 1903) [=Cidaris helenae] F66
    |    |--Dicyclocidaris Fell 1950 F66
    |    |    `--*D. denticulata Fell 1950 F66
    |    |--Pachycidaris Thiéry 1928 F66
    |    |    `--P. thieryi Collignon & Lambert 1928 [=Cidaris spinosa (preoc.), *P. spinosa] F66
    |    |--Anaulocidaris Zittel 1879 F66
    |    |    |--*A. buchi (Münster 1843) [=Cidaris buchi] F66
    |    |    `--A. testudo F66
    |    |--Mikrocidaris Döderlein 1887 [=Microcidaris Lambert & Thiéry 1909] F66
    |    |    |--*M. pentagona (Münster 1843) [=Cidaris pentagona] F66
    |    |    `--M. venusta F66
    |    |--Triadocidaris Döderlein 1887 F66
    |    |    |--*T. subsimilis (Münster 1843) [=Cidaris subsimilis] F66
    |    |    `--T. persimilis F66
    |    `--Miocidaris Döderlein 1887 [incl. Eotiaris Lambert 1900] F66
    |         |--M. cassiani Bather 1909 [=Cidaris klipsteini, *M. klipsteini] F66
    |         |--M. keyserlingi F66
    |         |--M. lorioli F66
    |         |--M. pakistanensis F66
    |         `--M. planus F66
    `--Cidaridae MG-H11
         |  i. s.: Acanthocidaris curvatispinis (Bell 1892) MG-H11
         |--Cidarinae F66
         |--Histocidarinae F66
         |--Rhabdocidarinae F66
         |--Goniocidarinae F66
         |--Ctenocidarinae F66
         `--Stereocidarinae [Stereocidaridae] F66
              |--Compsocidaris Ikeda 1939 F66
              |    `--*C. pyrsacantha Ikeda 1939 F66
              |--Sinaecidaris Fourtau 1921 F66
              |    `--*S. gauthieri Fourtau 1921 F66
              |--Temnocidaris Cotteau 1863 F66
              |    `--*T. magnifica Cotteau 1863 F66
              `--Stereocidaris Pomel 1883 (see below for synonymy) F66
                   |--*S. cretosa (Mantell 1835) [=Cidaris cretosa] F66
                   |--S. hudspethensis F66
                   |--S. hutchinsoni F66
                   |--S. japonica (Döderlein 1885) U67, F66 [=Dorocidaris japonica F66, *Phalacrocidaris japonica F66]
                   |--‘Cidaris’ malum [=*Typocidaris malum] F66
                   |--S. merceyi [=Cidaris merceyi] F66
                   |--S. sceptifera F66
                   |--S. sceptriferoides (Döderlein 1887) MG-H11
                   `--‘Cidaris’ tenuispinus Yoshiwara 1898 [=*Anomocidaris tenuispinus] F66

Stereocidaris Pomel 1883 [incl. Anomocidaris Agassiz & Clark 1907, Phalacrocidaris Lambert 1902, Typocidaris Pomel 1883] F66

*Type species of generic name indicated

REFERENCES

[B01] Boczarowski, A. 2001. Isolated sclerites of Devonian non-pelmatozoan echinoderms. Palaeontologia Polonica 59: 1–219.

[F66] Fell, H. B. 1966. Cidaroids. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 1 pp. U312–U339. The Geological Society of America, Inc., and The University of Kansas Press.

[MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O’Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[U67] Ubaghs, G. 1967. General characters of Echinodermata. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt. S. Echinodermata 1. General characters. Homalozoa—Crinozoa (except Crinoidea) vol. 1 pp. S3–S60. The Geological Society of America, Inc., and The University of Kansas: Lawrence (Kansas).