The Echinoid Directory

• Test globular in form; approximately as tall as wide or taller; relatively thin-shelled.
• Apical disc small, dicyclic, usually lost; gonopores at edge of genital plates. A distinct ring of tubercles on genital plates bordering the periproctal opening. Gonopores in female generally marginal and breaking through edge of plate. Periproctal opening subcircular; periproctal plates small with no distinct suranal.
• Ambulacral zones almost as wide as interambulacral zones. Plating trigeminate with plate compounding in echinoid style.
• Pore-zones broad, with pore-pairs in arcs of three forming a wide band; not expanding adorally and no phyllode development.
• Ambulacral plates rather sparsely tuberculate; each plate with primary tubercle adjacent to pore zone and usually with one or two slightly smaller tubercle towards the perradius forming a row in large individuals.
• Interambulacral plates wider than tall with small primary tubercle and other secondary tubercles; these not forming well-defined rows.
• Tubercles small; ambulacral and interambulacral tubercles of similar size; imperforate and more or less non-crenulate.
• Plates appear rather naked especially interradially, but no well developed adapical naked zone in interambulacra.
• Sutural pits usually absent; sometimes minute pits at triple suture points along the median sutures.
• Peristome rather small (ca. 30-35% test diameter), with buccal notches hardly developed.
• Perignathic girdle of apophyses and tall slender auricles that only just meet perradially at their tips.
• Spines short, uniform.

Recent; Australia.

Amblypneustes griseus Blainville, 1825, p. 81 [=Echinus ovum Lamarck, 1816, p. 48], by monotypy.

• A. formosa Valenciennes, 1846; Recent, Australia.
• A. grandis Clark, 1912; Recent, Australia.
• A. leucoglobus Doderlein. 1914; Recent, Australia.
• A. A. ovum (Lamarck, 1816); Recent, Australia.
• A. pachistus Clark, 1912; Recent, Australia, New Zealand.
• A. pallidus (Lamarck, 1816); Recent, Australia.

Euechinoidea; Camarodonta; Temnopleuroida; Temnopleuridae.

Very like Holopneustes, but with a primary tubercle to every compound ambulacral plate rather than on every second or third plate as in Holopneustes.

All of the Recent species are virtually impossible to distinguish based on test characters alone.

Agassiz, L. 1841. Observations sur les progress récens de l’histoire naturelle des echinoderms. Monographie d’Échinodermes vivans et fossiles. Seconde Monographie, première section, 20 pp. Petitpierre, Neuchâtel.

Mortensen, T. 1943. A monograph of the Echinoidea Part III.2, Camarodonta 1. C. A. Reitzel, Copenhagen.