The Echinoid Directory

• Test oval in outline with thin margin. Oral surface flat, upper surface conical towards apex.
• Internal supports marginal and concentric.
• 4 gonopores; apical disc subcentral. Hydropores in a groove.
• Petals elongate, weakly bowed and closed distally. Plating arranged with triads and diads.
• Food grooves poorly developed; simple and only developed close to the peristome.
• Ambulacral very much wider than interambulacral zones at ambitus.
• Basicoronal and first paired post-basicoronal plates enlarged but additional circlets included in oral surface.
• Periproct oral, towards posterior margin. Opening bounded by first, second and third pairs of interambulacral plates.

Middle Eocene to Late Oligocene of south eastern USA and the Caribbean.

Laganum eldridgei Twitchell 1915 by original designation.

• N. eldridgei (Twitchell, 1915); Middle to Late Eocene of south eastern USA and Jamaica.
• N. elegans (Sanchez Roig 1947); Late Oligocene, Ciego de Avila, Camaguey, Cuba.

Clypeasteroida; Scutellina; Laganiformes; Laganidae; Neolaganinae.

Presumed monophyletic.

The thin margin distinguishes this genus from Cubanaster. Wythella has a thinner margin than the type species of Neolaganum and slightly more plates making up the oral surface. The longer, more parallel petals distinguish Wythella from Weisbordella. In shape it is very closely comparable to the type species of Neorumphia, which is treated as a synonym.

J. W. Durham 1955. Classification of clypeasteroid echinoids. University of California Publications in Geological Sciences 31(4), 73-198.