The Echinoid Directory

• Test large and hemispherical with low ambitus and flattened base.
• Apical disc small, dicyclic, with larger circular periproctal opening.
• Ambulacra narrow with trigeminate plating; plate compounding arbaciid, with large element bearing the primary tubercle, a small demiplate and a tiny occluded plate. The occluded plate bears a very much reduced pore-pair.
• Ambulacral plates with single small primary tubercle; tubercles alternately offset so as to form two columns in larger individuals; perradial zone relatively broad.
• Interambulacral plates much wider than tall, bearing a row of subequal tubercles up to 10 abreast; tubercles sometimes in two irregular rows.
• Ambulacral and interambulacral tubercles of similar size; all tubercles imperforate and non-crenulate.
• Interradial zones above ambitus more or less naked.
• Peristome modest, a little sunken; buccal notches feeble.
• Basicornal interambulacral plate perserved at peristome edge; central and projecting interradially.
• Spines and lantern unknown; no primordial interambulacral plate.

Upper Cretaceous, North Africa and Middle East.

Protechinus paucituberculatus Noetling, 1897, p. 14, by original designation (type destroyed).

• P. paucituberculatus Noetling, 1897; Maastrichtian, Pakistan, Middle East, North Africa, Madagascar.
• P. emiratescus (Ali, 1989); Maastrichtian, United Arab Emirates.
• P. sphericus (Ali, 1992); Maastrichtian, United Arab Emirates.
• P. monotuberculatus (Smith, in Smith & Jeffery, 2000); Maastrichtian, United Arab Emirates.

Euechinoidea, Carinacea, Arbacioida Arbaciidae

The unique style of ambulacral plating immediately distinguishes Protechinus from all others. Its dicyclic apical disc and retention of a large primordial interambulacral plate are suggestive of Arbacioida.

The name Protoechinus Austin, 1860 is not a homonym of Protechinus and so Noetling's original genus name is valid, contra Lambert (1898) and subsequent authors, including Smith (1995) where a recent description of the genus can be found.

Noetling, F. 1897. Fauna of Baluchistan 1 (part 3). Fauna of the Upper Cretaceous (Maestrichtien) beds of the Mari Hills. Palaeontologica Indica 16th Series 1 (3), 1-79, pls 1-23.

Smith, A. B. 1995. Late Campanian -Maastrichtian echinoids from the United Arab Emirates - Oman borders region. Bulletin of the Natural History Museum, London (Geology Series) 51, 121-240.