The Echinoid Directory

• Test of medium size, elongate, subcylindrical with flattish base.
• Apical system anterior, tetrabasal, with four genital pores. Genital plate 2 is very large in comparison to the other genital plates and dominates the disc.
• Petals well developed, broad closing distally, the two columns in each of the paired petals of unequal length. Pores conjugate. Ambulacral plates with single pores beyond petals.
• Periproct marginal, longitudinal.
• Peristome anterior, subpentagonal.
• Bourrelets not protruding; forming a deep vertical walled entrance to the peristome.
• Phyllodes slightly broadened, single pored, the type species with typically six pores in the outer series in each half-ambulacrum, two in each inner series. In other species the two series better developed and with occasional pores in between.
• Buccal pores present.

Upper Cretaceous (Cenomanian-Maastrichtian) of France and the United Arab Emirates.

Arnaudaster gauthieri Lambert, 1920, p. 152; by subsequent designation of Lambert, 1920, p. 152

• Arnaudaster gauthieri Lambert, 1920; Cenomanian, France.
• Arnaudaster cylindriformis Smith, 1995; Maastrichtian, United Arab Emirates.

Irregularia; Cassiduloida; \'Gitoplampadids\'

Arnaudaster is similar to Parapygus, but differs primarily in having a more cylindrical shape, and distinctly asymmetric petals, the two columns in each of the paired petals of unequal length.

Lambert & Thiery (1909-1925, p. 353) and Mortensen (1948, p. 157) attribute this genus to Lambert (1920). Kier (1962, p. 104) points out that Lambert mentioned this genus in 1918, with a diagnosis in a footnote, and therefore 1918 is the correct date of publication.

Cooke (1955, p. 96) attributed a Late Albian species (his Arnaudaster colombianus) to this genus. However, according to Kier (1962, p. 105) this species has phyllodes that are double pored, with many pores pairs in each half-ambulacrum, and no buccal pores, and he thought this species should be referred to Pygorhynchus.

Lambert, J. 1918. Considerations sur la classification des echinides atelostomes. 1, Brachygnata et Procassiduloida. Memoires de la Societe academique de l'Aube 82,10-54.

Lambert, J. 1920. Sur quelques genres nouveaux d'Echinides Memoires de la Societe academique de l'Aube 84, 145-174.

P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections, 144 (3) 262 pp.

J. Lambert & P. Thiery. 1909-1925. Essai de nomenclature raisonnee des echinides. Libraire Septime Ferriere, Chaumont, 607 pp., 15 pls.

T. Mortensen. 1948. A monograph of the Echinoidea: 4 (1): Holectypoida, Cassiduloida. Reitzel, Copenhagen, 363 pp., 14 pls.

C. Wythe Cooke. 1955. Some Cretaceous echinoids from the Americas. U. S. Geological Survey Professional Paper 264-E, 87-112, pls 18-29.