The Echinoid Directory

Gentilia Lambert, 1918, p. 35

Diagnostic Features	Test of medium size, typically inflated, greatest width posterior to centre; slightly pointed posterior margin; steep rounded sides, flat adoral surface. Apical system anterior, tetrabasal with four gonopores. Petals in paired ambulacra well developed, broad, closed distally. Interporiferous zones broad, poriferous zones narrow; pores conjugate, outer pore slit-like, inner pore circular. Ambulacral plates beyond petals with only a single series of single pores. Ambulacrum III with very short petal or apetaloid. Pores in ambulacrum III single and arranged as a double series in each column. Peristome longitudinal, flush with the test. Periproct inframarginal, longitudinally ovate. Bourrelets slightly developed. Phyllodes broad, single pored with two series in each half-ambulacrum. Buccal pores rudimentary, or absent. Narrow naked granular zone in interambulacrum 5 behind peristome.
Distribution	Cretaceous (Cenomanian) of Syria and Morocco.
Name gender	feminine
Type	Gentilia tafileltensis Lambert 1918, p. 35: by subsequent designation of Lambert 1920, p. 154.
Species Included	G. tafileltensis Lambert; Cenomanian, Morocco. ?G. syriensis Kier, 1962; Cenomanian, Syria.
Classification and/or Status	Irregularia; Cassiduloida; Incertae sedis.
Remarks	Gentilia can be differentiated from Archiacia and Claviaster by the presence of only single pores in the ambulacral plates beyond the petals and in the phyllodes. In both Archiacia and Claviaster the ambulacral plates beyond the petals and the phyllodes have double pores. Kier (1962, p. 153) states that Archiacia is probably ancestral to Gentilia. Species (such as G. syriensis) that have a short petal III have tentatively been included in Gentilia. However, based on the development of this character, such species should be separated from the type species of Gentilia where petal III is completely absent. Close to Pseudopygurus and Termieria in having either a short or no petal in ambulacrum III, but differing from those taxa in having pores arranged biserially in ambulacrum III and in having an inner and outer series of pores in its phyllodes. It may be antecedent to these taxa. P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections, 144 (3) 262 pp. Lambert, J. 1918. Considérations sur la classification des échinides atelostomes. Mémoires de la Société académique de l’Aube, (3) 82, 9-54.