The Echinoid Directory

Echinus Linnaeus, 1758, p. 663

[?=Atactus Pomel, 1883, type species Psammechinus fischeri Cotteau, 1880 ]

Diagnostic Features	Apical disc dicyclic. Ambulacral plating trigeminate, with pore-pairs in oblique arcs of three forming a continuous adradial band. Ambulacral plates with primary tubercle only on every second or third plate. Pore-zones forming relatively broad and uniformly wide bands from apex to peristome. Interambulacral plates with central primary tubercle not strongly differentiated from secondaries; secondary tubercles relatively common. Globiferous pedicellariae with tubular blade and paired lateral teeth.
Distribution	Late Miocene to Recent, Atlantic, Mediterranean, Subantarctic
Name gender	masculine
Type	Echinus esculentus Linnaeus 1758, p. 663, by subsequent designation of Fell & Pawson, 1966, p. 431.
Species Included	E. esculentus Linnaeus, 1758; Recent, N. Atlantic. E. tenuispinus Norman 1868; Recent. E. acutus (Lamarck, 1816); Recent, Atlantic. E. anchistus Clark, 1912; Recent, Chile. E. gilchristi Bell, 1904; Recent, South Africa. E. multidentatus Clark, 1925; Recent, Kermadec Islands. E. melo Lamarck, 1816; Recent, Atlantic and Mediterranean. E. stenoporus (Mortensen, 1942); Recent, S. Africa. E. wallisi Agassiz, 1880; Recent, West Atlantic.
Classification and/or Status	Camarodonta; Echinoida; Echinidae. Probably monophyletic.
Remarks	Mortensen (1926) included in Echinus forms with both primary tubercles on every ambulacral plate, and those with primary tubercles on every second or third compound plate. However, Fell & Pawson (1966) erected a new genus Gracilechinus, for species in which a primary ambulacral tubercle occurs on each plate. Psammechinus differs in being altogether more densely tuberculated and Parechinus is distinguished by its three clearly discrete vertical columns of pore-pairs. Stirechinus has a vertical ridge connecting primary interambulacral tubercles. Finally, Stirechinus and Dermechinus both have much more strongly granular plating. From a palaeontological point of view, the distinction of Echinus from a number of other genera is difficult. Linnaeus, C. 1758. Tomus I. Syst. nat., ed. 10. Holmiae, Laurentii Salvii: [1-4], 1-824. [Online] Mortensen, T. 1943. A monograph of the Echinoidea Part III, 3. Camarodonta II. C. A. Retzel, Copenhagen. Fell, H. B. & Pawson, D. L. 1966. Echinacea. In R. C. Moore (ed.) A Treatise on Invertebrate Paleontology. Part U Echinodermata 3. Asterozoa-Echinozoa. University of Kansas Press and the Geological Society of America, Boulder.