The Echinoid Directory

• Test of small to medium size, broad with greatest width posterior to centre, moderately inflated with thick margins.
• Apical system tetrabasal, four gonopores, no complemental plates in the disc.
• Petals long, open, poriferous zones narrowing distally but remaining open, pores conjugate, outer pore transversely elongated; all ambulacral plates with double pores.
• Periproct supramarginal, longitudinal, with short anal groove; opening at some distance from the apical disc.
• Peristome anterior, subpentagonal; opening without vertical-walled entrance but oral surface weakly sunken towards peristome.
• Bourrelets hardly developed.
• Phyllodes narrow, not bowed towards peristome, double pored, with two series of pore-pairs in each half-ambulacrum.
• No buccal pores.

Middle Jurassic (Bathonian) to Upper Cretaceous (Turonian) of Europe, North Africa, India.

Nucleolites scutatus Lamarck, 1816, p. 36; by subsequent designation of De Blainville, 1825, p. 212.

• N. scutatus Lamarck, 1816; Bajocian-Kimmeridgian, Europe.
• N. brodei (Wright, 1859); Tithonian, UK
• N. burgundiae (Cotteau, 1871); Bathonian, France.
• N. cerceleti Desor in Agassiz & Desor, 1847; Aptian-Albian, England, France.
• N. elongatus Chiplonkar & Badve, 1972; Turonian, India.
• N. lorioli (Cotteau, 1871); Callovian, Europe.
• N. cordatus (Goldfuss, 1826); Cenomanian, France.
• N. haimei (Wright, 1859); Tithonian, England, France.
• N. subquadratus (L. Agassiz, 1839); Valanginian, Switzerland.

Lambert & Thiery (1909-1925) refer 7 species to Nucleolites and 12 to Echinobrissus.

Irregularia; Neognathostomata; \'nucleolitid\'.

Nucleolites is distinguished from Pseudosorella by having the periproct separated from the apical disc and in being subquadrate in outline rather than circular. Nucleolites closely resembles some species of Crotoclypeus but has phyllode pore-pairs arranged as two discrete columns, the inner with half the number of pore-pairs than the outer series.

Within the \'nucleolitids\' there is a sequential migration of the periproct from the posterior ocular plates of the apical disc. In the primitive form (e.g. Pseudosorella) the periproct is in contact with the posterior ocular plates of the apical system, and is in fact entriely surrounded by the posterior plates of the disc. There is a long anal anal sulcus stetching to the ambitus. In the advanced form the periproct (e.g. Nucleolites) has migrated outside the disc (becoming truly exocyclic), towards the posterior margin resulting in a shorter anal sulcus. In the latest \'nucleolitids\' (e.g. Catopygus) there is no anal sulcus at all. For morphometric analysis see Moyne et al., 2003).

Considerable confusion has arisen between Nucleolites and Echinobrissus. Lambert & Thiery (1909-1925) and Mortensen (1948) used the name Echinobrissus even though they attributed it to a pre-Linnaean author (Breynius, 1732); considering Nucleolites clunicularis (Phillips, 1829) the type species. Kier (1962, p. 63) notes that N. clunicularis was not included among the two species that Grey referred to his Echinobrissus, and therefore cannot be the type species. Kier (1962, p. 63) states that Cooke\'s (1953) designation of N. scutatus as the type species is correct, thus making Echinobrissus a junior objective synonym of Nucleolites.

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

Lamarck, J.B. de (1801). Systeme des Animaux sans vertebres, ou tableau général des classes, des ordres et des genres de ces animaux; Présentant leurs caractères essentiels et leur distribution, d'après la considération de leurs rapports naturels et de leur organisation, et suivant l'arrangement établi dans les galeries du Muséum d'Hist. Naturelle, parmi leurs dépouilles conservées. Précédé du discours d'ouverture du Cours de Zoologie, donné dans le Muséum National d'Histoire Naturelle l'an 8 de la République.. pp. i-viii, 1-432. Paris: Chez l'Auteur, au Muséum d'Hist[oire] Naturelle; Chez Derteville, Libraire, rue du Battoir n° 16, quartier de l'Odéon.

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.

S. Moyne, J. Thierry & D. Marchand. (2003). Analysis of the disparity of Nucleolites (Echinoidea, Cassiduloidea) from the Middle-Late Jurassic of the Paris Basin: Taxonomic and biodiversity implications. Proceedings of the sixth European conference on Echinoderm research, Echinoderm Research 2001, J. Feral, B. David (eds). A. A. Balkema, Netherlands. 105-112 pp.

C. Wythe Cooke. 1953. American Upper Cretaceous Echinoidea. United States Geological Survey, Professional Paper, 254, 44 pp., 16 pls.

Barras, C. G. 2006. British Jurassic irregular echinoids. Monograph of the Palaeontographical Society no. 625 (part of volume 159 for 2005), 1-168, pls 1-14.