The Echinoid Directory

• Test ovate in outline; no anterior sulcus.
• Apical disc disjunct with posterior ocular plates widely separated. Ocular plates II and IV meeting behind genital plate 2. Genital plates 1 and 4 small. Interambulacral series 1 and 4 separated by single or double irregular row of elongate catenal plates.
• Posterior oculars bordering periproct so that ambulacra I and V end at apex of periproct; elongate and extending round lateral margins of periproct.
• Ambulacra all similar; pore-pairs small. Aboral plates relatively low, wide and closely packed.
• Short and distinct phyllodes developed (5-6 pore-pairs enlarged towards peristome); one of each pair of basicoronal ambulacral plates with two pore-pairs.
• Peristome anterior of centre, small, subcircular; facing downwards.
• Plastron plating protosternous; initial plates small.
• Peripoct small, tear-drop-shaped; not sunken and no subanal indentation. Catenal plates usually present as continuous series between posterior oculars and start of periproct.
• Fine scattered tubercles set in groundmass of granules.

Lower and Middle Jurassic (Toarcian-Callovian), Europe.

Spatangites ovalis Leske, 1778, p. 253, by subsequent designation of Beurlen, 1934, p. 65.

• P. ovalis (Leske, 1778); Bajocian - Callovian, Europe; ?Upper Pliensbachian, France ( Vadet et al. 1995) [includes P. pictaviensis].
• P. prior Lambert, 1914; Toarcian, France [poorly known - may be an Orbignyana].
• P. analis (Agassiz, 1835); Upper Bathonian-Lower Callovian, Europe [includes P. excentricus (Goldfuss)].

Irregularia; Stem group Atelostomata; Collyritidae.

Paraphyletic by exclusion of Cyclolampas.

Distinguished from the rather similar Pygorhytis by having the periproct and peristome flush, without the obvious subanal groove and keels of that genus. Pygomalus also differs in having ambulacra and the peristome flush and not sunken, in contrast to Pygorhytis. Close to Collyrites, but easily distinguished by having the posterior ambulacra eminating from ocular plates that border the periproct, rather than at some distance removed from the periproct.

The Upper Pliensbachian record of this genus is discussed in Vadet et al. (1995)

Barras, C. 2006. British Jurassic irregular echinoids. Monograph of the Palaeontographical Society, 1-168, pls 1-14 (publication number 625).

Jesionek-Szymanska, W. 1963. Echinides irreguliers du Dogger de Pologne. Actes Palaeontologica Polonica 8(3), 293-396.

Pomel, A. A. 1883. Classification méthodique et Genera des Échinides vivante et fossiles. Thèses présentées a la Faculté des Sciences de Paris pour obtenir le Grade de Docteur ès Sciences Naturelles 503, Aldolphe Jourdan, Alger, 131 pp.
 

Solovjev, A. 1971. Late Jurassic and Early Cretaceous disasterids of the USSR. Transactions of the Palaeontological Institute, Academy of Sciences of the USSR 131, 1-120, pls 1-16 [in Russian]

Thierry, J. 1992. Variations morphologiques de l\'oursin irregulier Disasteroidea Collyrites (Pygomalus) analis (Agassiz). Geobios Memoir special 14, 123-132.

Vadet, A., Thierry, J., Rioult, M. & Guitton, M. 1995. Presence de Pygomalus ovalis dans le Carixien superieur. Memoires de la Societe academique de Boulonnais 16, 60-62.