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Agassizia algarbiensis Ferreira, 1962

Diagnostic Features	Test distinctly antero-posteriorly elongated (test width about 80-90% of test length) and slightly depressed (test height about three-quarters of test length). Apical disc lies to the posterior of centre, up to two-thirds of test length from the anterior margin. Gonopores first appearing in specimens approximately 16 mm long. Anterior paired petal length about one-half of test length; the posterior ones are as long as about one-fifth of test length. The anterior paired petals form an angle of about 90 degrees with each other, the posterior ones an angle of 70 to 100 degrees. The peristome is located one-eigth to one-fourth of test length from anterior margin. The adoral border of the periproct is located approximately at mid-height of test.
Distribution	Lower Miocene (Burdigalian) and Middle Miocene of Portugal.
Type	Lectotype, Museu Geologico (Lisbon, Portugal) MG 3793a; paralectotypes 3793b-c.
Classification and/or Status	A species of Agassizia.
Remarks	A. zitteli Fuchs, 1883, the other Agassizia species that occurs in the Portuguese Miocene, differs from A. algarbiensis by its relatively wider and higher test, more central apical disc, more anterior peristome, more sunken petals and longer posterior petals. A. wilmingtonica differs by its lower test and longer posterior petals. A. powersi differs by its distinctly more anterior apical disc. A. clevei Cotteau, 1875 from the Late Eocene to Miocene of the Caribbean is very similar to A. algarbiensis and may be very difficult to distinguish if only single specimens are considered. However when populations are compared they can be distinguished. In A. algarbiensis the apical disc is never as posteriorly displaced as it can be in A. clevei and the angle formed by the anterior paired petals is never as wide as it can be in the Caribbean species. Ferreira, O. V. 1962. Nota sobre a presenca do genero 'Agassizia' no Miocenico do Algarve. Comunicacoes dos Servicos Geologicos de Portugal, Lisboa, 46, 293-295, 1 pl. Pereira, P. 2010. Echinoidea from the Neogene of Portugal mainland. Palaeontos, Mortsel, 18, 154 pp, 37 pls.