The Echinoid Directory

Polycyphus L. Agassiz, in Agassiz & Desor, 1846, p. 361

Diagnostic Features	Test domed, flattened below. Apical disc small, subcircular; dicyclic with genital plates a little wider than tall. G2 enlarged compared to others. Oculars small. periproct large subpolygonal. Ring of tubercles on genital plates. Ambulacra trigeminate with pore-pairs in strong arcs forming adradial band throughout. Plate compounding arbaciid, with upper and lower elements narrow wedge-shaped elements that end before reaching the perradius. Adapically all elements reach perradius. Short phyllodes developed adorally. Ambulacral plates generally with single tubercle close to perradial band. Second, slightly smaller tubercle present perradially on ambital and adoral plates. Dense granulation elsewhere. Interambulacral plates wider than tall. A single primary tubercle centrally placed, with smaller secondary flanking tubercles on adradial and interradial sides on adapical plates; becoming as row of subequal tubercles, up to 4 abreast at ambitus and 2 adorally; marked increase in size of tubercles. Ambulacral and interambulacral tubercles of similar size. Narrow aboral naked interradial zone. Primary tubercles imperforate and non-crenulate. Peristome large, weakly sunken; buccal notches moderately deep and sharp. Spines and lantern unknown; no primordial interambulacral plate.
Distribution	Middle-Upper Jurassic, Europe, North Africa, Arabian Peninsula.
Name gender	masculine
Type	Polycyphus nodulosus Agassiz & Desor, 1846, p. 361 (non Munster), by monotypy [= Polycyphus normannus Desor, 1858, p. 117]
Species Included	P. normannus Desor, 1848; Bathonian, western Europe. P. arabicus Kier, 1972; Bathonian, Saudi Arabia. P. paucituberculatus Kier, 1972; Callovian, Saudi Arabia.
Classification and/or Status	Euechinoidea, Echinacea, Stomechinidae.
Remarks	Distinguished from Stomechinus and Psephechinus by having interambulacral tubercles above the ambitus arranged into well-defined vertical columns. The name Polycyphus was first proposed by Agassiz & Desor (1846) for a specimen originally identified as Polycyphus nodulosus (Munster) but later renamed Polycyphus normannus by Desor (1858) who correctly recognized its distinction from Munster\'s species. Agassiz, L. & Desor, P. J. E. 1846-1847. Catalogue raisonné des familles, des genres, et des espèces de la classe des échinodermes. Annales des Sciences Naturelles, Troisième Série, Zoologie : 6 (1846): 305-374, pls. 15-16; 7 (1847): 129-168; 8 (1847): 5-35, 355-380.