The Echinoid Directory

Contributed by Andrew Smith, July 2008

Eodiadema Duncan, in Wilson & Crick 1889, p. 339

Diagnostic Features	Test small, with domed upper surface Apical disc hemicyclic, with posterior two ocular plates contacting periproct. Ambulacra straight, with trigeminate plating throughout. Plate compounding acrosaleniid style, with primary tubercle overlapping two elements in each triad. All three elements identical in shape and reaching perradius. Interambulacra with single primary tubercle that is perforate and crenulate. Interradial zone broad and granular adapically. Primary tubercles distinctly smaller on adapical surface. Peristome relatively large, slightly sunken and with rather open, U-shaped buccal notches. Spines and lantern unknown.
Distribution	Lower Jurassic (Pliensbachian), England
Name gender	neuter
Type	Eodiadema granulatum Wilson, in Wilson & Crick, 1889. lectotyps: BMNH E76506 by subsequent designation of Smith 2016, p. 71.
Classification and/or Status	Subjective junior synonym of Glyptodiadema Pomel, 1883
Remarks	Duncan, 1889. A revision of the genera and great groups of the Echinoidea. Zoological Journal of the Linnean Society, 23, 1-331. Smith, A. B. 2016. British Cretaceous regular echinoids. Part 2 Carinacea. Monographs of the Palaeontographical Society (no. 646), pp. 69-176, pls 42-82. Wilson, E. in Wilson, E. & Crick, W. D. 1889. The Lias Marlstone of Tilton, Leicestershire. Geological Magazine 6 (dec. 3): 337-342, pl. 10.