Belongs within: Echinozoa.
Contains: Cidarinae, Histocidarinae, Rhabdocidarinae, Goniocidarinae, Ctenocidarinae, Archaeocidaris.
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. The Lower Carboniferous to Lower Jurassic Miocidaridae had a partially flexible test with interambulacral plates in two columns. 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 (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 [Archaeocidaroida, Cidaroidea]
| i. s.: Lanternarius Regnéll 1956F66
| `--*L. latens Regnéll 1956F66
| Plesiocidaris Pomel 1883SG93, FP66
| |--*P. alpina (Agassiz 1840) [=Hemicidaris alpina]FP66
| |--P. durandiFP66
| `--P. florida (Merian 1855)SG93
| Leptechinus Gauthier 1889SG93, FP66 (see below for synonymy)
| |--*L. heinzi (Peron & Gauthier 1889) [=Cyphosoma heinzi, *Peronia heinzi]FP66
| `--L. jutieri (Cotteau 1883)SG93 [=Pleurodiadema jutieriFP66, *Prototiara jutieriFP66]
|--DiplocidaridaeF66
| |--Tetracidaris Cotteau 1872F66
| | `--*T. reynesi Cotteau 1872F66
| `--Diplocidaris Desor 1855 [=Alternocidaris Quenstedt 1873; incl. Diplotiaris Quenstedt 1872]F66
| |--*D. gigantea [=Cidaris gigantea, *Alternocidaris gigantea]F66
| |--D. bicarinata Weber 1934SG93
| |--D. etalloniF66
| |--D. menchikoffi Lambert 1937SG93
| `--D. mirandaF66
|--CidaridaeF66
| | i. s.: Acanthocidaris curvatispinis (Bell 1892)MG-H11
| | Leurocidaris montanaro (Zardini 1973)SG93
| |--CidarinaeF66
| |--HistocidarinaeF66
| |--RhabdocidarinaeF66
| |--GoniocidarinaeF66
| `--CtenocidarinaeF66
|--HyattechinidaeSG93
| |--Perischodomus M’Coy 1849SG93, K66 [incl. Tretechinus Tornquist 1897K66]
| | |--*P. biserialis M’Coy 1849K66
| | |--P. fraiponti Jackson 1929SG93
| | `--P. illinoisensis Worthen & Miller 1883 [=*Tretechinus illinoisensis]K66
| `--Hyattechinus Jackson 1912K66
| |--*H. beecheri Jackson 1912K66
| |--H. dixoni Hawkins 1935SG93
| |--H. elegans Jackson 1929SG93
| `--H. toreumaticus Hawkins 1935SG93
|--ArchaeocidaridaeF66
| |--ArchaeocidarisF66
| |--Nortonechinus Thomas 1920F66
| | `--*N. welleri Thomas 1920F66
| |--Polytaxicidaris Kier 1958F66
| | `--*P. dyeri Kier 1958F66
| |--Silurocidaris Regnéll 1956F66
| | `--*S. clavata Regnéll 1956F66
| |--Xenocidaris Schultze 1866F66
| | `--*X. clavigera Schultze 1866F66
| `--Lepidocidaris Meek & Worthen 1873F66
| `--*L. squamosa Meek & Worthen 1873F66
| |--L. s. squamosaSG93
| `--L. s. anglica Hawkins 1935SG93
|--PsychocidaridaeF66
| |--Psychocidaris Ikeda 1935F66
| | `--*P. ohshimai Ikeda 1935F66
| |--Anisocidaris Thiéry 1928F66
| | `--*A. bajocensis (Cotteau 1880) [=Cidaris bajocensis]F66
| |--Caenocidaris Thiéry 1928F66
| | `--*C. cucumifera (Agassiz 1840)F66, SG93 [=Cidaris cucumiferaF66]
| |--Merocidaris Thiéry 1928F66
| | `--*M. honorinae (Cotteau 1880) [=Cidaris honorinae]F66
| |--Sardocidaris Lambert 1907F66
| | `--*S. piae Lambert 1907F66
| `--Tylocidaris Pomel 1838F66
| |--*T. clavigera (König 1820) [=Cidaris clavigera]F66
| `--T. walcottiF66
`--Miocidaridae [Streptocidaridae, Streptocidarinae]F66
|--Aplocidaris Lambert & Thiéry 1909F66
| `--*A. helenae (de Regny 1903) [=Cidaris helenae]F66
|--Dicyclocidaris Fell 1950F66
| `--*D. denticulata Fell 1950F66
|--Pachycidaris Thiéry 1928F66
| `--P. thieryi Collignon & Lambert 1928 [=Cidaris spinosa (preoc.), *P. spinosa]F66
|--Anaulocidaris Zittel 1879F66
| |--*A. buchi (Münster 1843) [=Cidaris buchi]F66
| `--A. testudoF66
|--Mikrocidaris Döderlein 1887 [=Microcidaris Lambert & Thiéry 1909]F66
| |--*M. pentagona (Münster 1841)F66, SG93 [=Cidaris pentagonaF66]
| `--M. venustaF66
|--Triadocidaris Döderlein 1887F66
| |--*T. subsimilis (Münster 1843) [=Cidaris subsimilis]F66
| `--T. persimilisF66
`--Miocidaris Döderlein 1887 [incl. Eotiaris Lambert 1900]F66
|--M. cassiani Bather 1909 [=Cidaris klipsteini, *M. klipsteini]F66
|--M. cannoni Jackson 1912SG93
|--M. connorsi Kier 1965SG93
|--M. keyserlingi (Geinitz 1848)SG93
|--M. lorioliF66
|--M. pakistanensisF66
`--M. planusF66
Leptechinus Gauthier 1889SG93, FP66 [=Peronia Duncan 1899 nec Fleming 1822 nec Robineau-Desvoidy 1830FP66; incl. Prototiara Lambert 1900FP66]
*Type species of generic name indicated
References
[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.
[FP66] Fell, H. B., & D. L. Pawson. 1966. Echinacea. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 2 pp. U367–U440. The Geological Society of America, Inc., and The University of Kansas Press.
[K66] Kier, P. M. 1966. Noncidaroid Paleozoic echinoids. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 1 pp. U298–U312. 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.
[SG93] Simms, M. J., A. S. Gale, P. Gilliland, E. P. F. Rose & G. D. Sevastopulo. 1993. Echinodermata. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 491–528. Chapman & Hall: London.