Toxaster retusus, from the Natural History Museum.

Belongs within: Irregularia.

The Toxasteridae are a group of heart urchins known from the Lower Cretaceous to the present, characterised by possession of a relatively primitive apical system, together with a typical lack of fascioles and/or primary spines. They are represented in the modern fauna by the bathyal Indonesian genus Isopatagus, which is the only living spatangoid urchin with circumoral tube feet possessing double pores (Fischer 1966).

Characters (from Fischer 1966): Apical system normally ethmophract (posterior genital plates mutually contiguous), gonopores 3 or 4; paired ambulacra petaloid, generally open, frontal ambulacrum petaloid or not; ambital and circumoral ambulacral pores double; fascioles usually absent; primary spines absent; plastron protamphisternous to mesamphisternous.

<==Toxasteridae [Toxasterina]F66
    |--Adytaster Lambert 1895 [=Adetaster Delage & Hérouard 1904]F66
    |    `--*A. lucentinus (Cotteau 1890) [=Cyclaster lucentinus]F66
    |--Aphelaster Lambert 1920F66
    |    `--*A. integer Lambert 1920F66
    |--Douvillaster Lambert 1917 [=Hypsaster Pomel 1883 non Pomel 1869]F66
    |    `--*D. vatonnei (Coquand 1878) [=Epiaster vatonnei, *Hypsaster vatonnei]F66
    |--Enallopneustes Pomel 1883F66
    |    `--*E. jullieni (Peron & Gauthier 1881) [=Holaster jullieni]F66
    |--Isomicraster Lambert 1901F66
    |    `--*I. stolleyi Lambert 1901F66
    |--Macraster Roemer 1888F66
    |    `--*M. texanus Roemer 1888F66
    |--Mokotibaster Lambert 1933F66
    |    `--*M. hourequi Lambert 1933F66
    |--Polydesmaster Lambert 1920F66
    |    `--*P. fourtaui Lambert 1920F66
    |--Palmeraster Sánchez Roig 1949F66
    |    |--*P. palmeri Sánchez Roig 1949F66
    |    `--P. herreraiF66
    |--Heteraster d’Orbigny 1853 (see below for synonymy)F66
    |    |--*H. oblongus (Brongniart 1821) [=Spatangus oblongus]F66
    |    |--H. grenovii (Forbes 1852) [=Hemipneustes grenovii, *Enallaster grenovii]F66
    |    |--‘Epiaster’ michelini (Agassiz 1847)SG93
    |    |--H. musandamensis Lees 1928SG93
    |    `--H. trigonalis (Desor 1847) [=Micraster trigonalis, *Epiaster trigonalis]F66
    `--Toxaster Agassiz 1840 (see below for synonymy)F66
         |--*T. retusus (Lamarck 1816) [=Spatangus retusus]F66
         |--T. africanus (Coquand 1875)SG93
         |--‘Spatangus’ argilaceus Phillips 1829 [=*Hypsaster argilaceus]F66
         |--‘Echinospatagus’ breyniusi d’Orbigny 1859 [=*Miotoxaster breyniusi]F66
         |--T. complanatusSS05
         |--‘Echinospatagus’ hofmanniM79
         |--T. lafittei Devriès 1960SG93
         |--*Pliotaxaster’ lyonsi Fourtau 1907F66
         `--T. rochi Lambert 1933SG93
Pre-Linnean: Echinospatagus cordiformis Breynius 1732F66

Heteraster d’Orbigny 1853 [incl. Enallaster d’Orbigny 1853, Epiaster d’Orbigny 1854, Pseudoepiaster Seunes 1888, Taeniaster Lambert 1895 non Billings 1858]F66

Toxaster Agassiz 1840 [incl. Echinospatagus d’Orbigny 1853, Hypsaster Pomel 1883, Miotoxaster Pomel 1883, Pliotaxaster Fourtau 1907]F66

*Type species of generic name indicated


[F66] Fischer, A. G. 1966. Spatangoids. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 2 pp. U543–U628. The Geological Society of America, Inc., and The University of Kansas Press.

[M79] Müller, A. H. 1979. Fossilization (taphonomy). In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A2–A78. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[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.

[SS05] Stockley, B., A. B. Smith, T. Littlewood, H. A. Lessios & J. A. Mackenzie-Dodds. 2005. Phylogenetic relationships of spatangoid sea urchins (Echinoidea): taxon sampling density and congruence between morphological and molecular estimates. Zoologica Scripta 34: 447–468.

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