The Echinoid Directory

Tripylaster Mortensen 1907, p. 122

Diagnostic Features	Test ovate with deep anterior sulcus; posterior face truncate. Test depressed in profile with rounded ambitus. Apical disc ethmolytic with three gonopores (no gonopore in plate G2); central. Anterior ambulacrum deeply sunken aborally with uniserial pore-pairs along edge. Tube-feet with large disc supported by finger-like rosette. Petals somewhat sunken, but never forming marsupia in the females. Peristome sunken and facing forward into frontal groove. Labrum projecting to cover peristome in oral view. Labral plate short and wide, not extending beyond amb plate 1. Periproct on posterior truncate face. 3-4 subanal tube-feet present. Peripetalous and latero-anal fascioles present.
Distribution	Recent, southern South America.
Name gender	masculine
Type	Tripylus philippii Gray, 1851, p. 132, by original designation.
Species Included	Only the type species.
Classification and/or Status	Spatangoida, Paleopneustina, Schizasteridae. Monotypic.
Remarks	Differs from Tripylus in having a sunken anterior ambulacrum and much shorter posterior petals. Close to Brisaster, differing only in having a subcentral apical disc. Very similar to Victoriaster, differing from that genus in having three not four gonopores. Mortensen, T. 1907. Danish Ingolf Expedition 4(2) Echinoidea, part 2, p. 122. Mortensen, T. 1951. A monograph of the Echinoidea V. Spatangoida 2. C. A. Reitzel, Copenhagen.