The Echinoid Directory

• Test wheel-shaped, flattened below and above.
• Apical disc large, pentagonal, a little more than half of the test diameter; plating not firmly bound to corona; always lost.
• Ambulacral plating simple at ambitus and bigeminate above and below. Pore-pairs uniserial, with slight pore-crowding close to the peristome. Plate compounding with all elements reaching the perradial suture.
• Ambulacral plates with single large tubercle leaving little perradial space
• Interambulacral plates much wider than tall, slightly flexed; plates at the ambitus much lower than those either adapically or adorally. Plates with a single row of subequal tubercles, up to 7 abreast; little space for granules.
• Ambulacral and interambulacral tubercles of similar size. Tubercles imperforate and non-crenulate; mamelon relatively large and little or no surrounding platform.
• Narrow naked interradial zone extending to ambitus.
• Peristome large, similar in size to apical disc; flush; buccal notches small but sharp.
• Spines and lantern unknown; no primordial interambulacral plate.

Upper Cretaceous (Maastrichtian), The Netherlands.

Winkleria maastrichtensis Engel, 1964, p. 207, by monotypy.

• Only the type species.

Phymosomatoida, unnamed family.

Monotypic.

Winkleria is close to Gomphechinus and Plistophyma, but is easily distinguished by its uniserial pore zones and simple ambital plating.

Engel, H. 1964. On Winkleria maastrichtensis nov. gen. et nov. spec. (Echinoidea, Regularia, Stirodonta, Phymosomina, ?Phymosomatidae) from the Upper Cretaceous (Md) of Maastricht (Limburg, Netherlands. Beaufortia 10(126), 207-211, 1 pl.

Smith, A. B. & Jeffery, C. H. 2000. Maastrichtian and Palaeocene Echinoids: a key to world faunas. Special Papers in Palaeontology 63, 1-404.

Jagt, J. W. M. 2001. Late Cretaceous-Early Palaeogene echinoderms and the K/T boundary in the southeast Netherlands and northeast Belgium - Part 4: Echinoids. Scripta Geologica 121, 181-375.