The Echinoid Directory

• Test small with rounded margin; ovate in outline.
• 4 gonopores.
• Internal radial partitions present; both concentric and marginal.
• Petals very poorly developed, with distinct pore-pairs, one per plate.
• Interambulacral zones much narrower than ambulacral zones at ambitus.
• All interambulacrum disjunct on oral surface. Basicoronal interambulacral plates small and enclosed by ambulacral basicoronal plates; separated by three pairs of ambulacral plates from succeeding interambulacral plates.
• A few interambulacral plates subambitally, separated from aboral series by ambital circle of enlarged ambital ambulacral plates.
• Interambulacral plates continue on aboral surface to apex as a biseries.
• Periproct aboral, towards posterior margin; bounded by third pair of interambulacral plates and marginal ambulacrals.
• Food grooves absent.
• Pores and tubercles not arranged into combed areas.
• Females with deep brood pouches developed on oral surface anterior to the peristome.

Lower Miocene of south Australia.

Willungaster scutellaris Philip & Foster, 1971, p. 687, by original designation.

• Only the type species.

Clypeasteroida; Clypeasterina; Arachnoididae; Arachnoidinae.

Monotypic.

This was separated from the otherwise very similar Scutellinoides because it shows sexual dimorphism. It also differs from Scutellinoides in having interambulacral zones continuing above ambitus (absent in Scutellinoides). Differs from Fossulaster in having interambulacral plates aborally between rudimentary petals. Orbispala differs in having the aboral surface composed of just 10 large ambulacral plates each of which has a row of pore-pairs.

Philip, G. M. & Foster, R.J. 1971. Marsupiate Tertiary echinoids from south-eastern Australia and their zoogeographic significance. Palaeontology 14, 666-695.

Wang, C.-C. 1994. Phylogenetic analysis of the fossulasterid echinoids (Order Clypeasteroida) from Australia. Journal of the Geological Society of China 37, 225-246.