Hemiaster

Clockwise from lower left, (a) aboral, (b) oral, (c) lateral and (d) posterior views of Hemiaster bufo, from Fischer (1966).

Belongs within: Hemiasterina.

Hemiaster is a genus of broad and high heart urchins known from the Lower Cretaceous to the present (Fischer 1966).

See also: Hemiaster: an echinoid with heart.

Characters (from Fischer 1966): Test broad, high relative to length, abruptly truncated in rear, showing slight frontal sinus; apical system ethmophract, with four gonopores; frontal ambulacrum nonpetaloid or semipetaloid, with small round pores; paired ambulacra having relatively short petals, frontal pair longest.

<==Hemiaster Agassiz 1847 [incl. Leucaster Gauthier in Peron 1887, Peroniaster Gauthier 1887, Perionaster (l. c.)] F66
    |  i. s.: ‘*Peroniaster’ cotteaui Gauthier 1887 F66
    |         ‘*Leucaster’ remensis Gauthier 1887 F66
    |         H. texanus F66
    |--H. (Hemiaster) [incl. Integraster Lambert & Thiéry 1924 non Döderlein 1920] F66
    |    |--*H. (H.) bufo (Brongniart 1822) [=Spatangus bufo] F66
    |    `--H. (H.) ligeriensis d’Orbigny 1853 [=H. (*Integraster) ligeriensis] F66
    |--H. (Bolbaster Pomel 1869) F66
    |    `--H. (*B.) prunella (Lamarck 1816) [=Spatangus prunella] F66
    |--H. (Gregoryaster Lambert 1907) F66
    |    `--H. (*G.) coranguinum (Gregory 1892) [=Pericosmus coranguinum] F66
    |--H. (Holanthus Lambert & Thiéry 1924) F66
    |    `--H. (*H.) hickmanni Koehler 1914 F66
    |--H. (Leymeriaster Lambert & Thiéry 1924) F66
    |    `--H. (*L.) leymeriei Agassiz 1847 F66
    |--H. (Mecaster Pomel 1883) F66
    |    `--H. (*M.) fourneli Agassiz in Agassiz & Desor 1847 F66
    `--H. (Trachyaster Pomel 1869) F66
         `--H. (*T.) globosus (Pomel 1869) [=*Trachyaster globosus] F66

*Type species of generic name indicated

REFERENCES

[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.