The Echinoid Directory

• Test flattened above and below; relatively thick.
• Apical disc unknown.
• Interambulacra with 5-6 plates in a series. Primary tubercles perforate and weakly crenulate; areoles circular and incised. Areoles separated on all plates.
• One fully formed adapical plate lacking a primary tubercle.
• Scrobicular tubercles differentiated; radially elongated; extrascrobicular zones narrow with just a single band of secondary tubercles and granules.
• Small sutural pits at interradial triple junctions.
• Ambulacra narrow and weakly sinuous. Pore-pairs slightly oblique, non-conjugate and with raised interporal ridge.
• Perradial zone with marginal series of primary tubercles with mamelons and inner series of smaller secondary tubercles.
• Peristome and primary spines unknown.

Lower Cretaceous (Upper Aptian); Egypt.

Sinaecidaris gauthieri Fourtau, 1921, p. 9, by original designation.

• Only the type species.

Cidaroida; Cidaridae; Stereocidarinae.

Monotypic.

Fourtau (1921) established this genus as a Typocidaris that had crenulate tuberculation. However, the crenulation is weakly developed here, as it is in adapical plates of Typocidaris. It differs from Typocidaris and all other Stereocidarinae in having primary interambulacral tubercles with confluent scrobicular circles: in Typocidaris the scrobicular circles are widely separated in each column.

Fourtau, R. 1921. Catalogue des invertebres fossiles de l'Egypte. Terrains Cretaces. 3me Partie: Echinodermes (Supplement). Geological Survey of Egypt Palaeontology Series 5, 1-101, pls 1-11.