The Echinoid Directory

Lajanaster Lambert & Sanchez Roig, in Sanchez Roig 1926, p. 100

Diagnostic Features	Test ovate without anterior sulcus. Depressed in profile with broad flat base and relatively sharp ambitus. Apical disc ethmolytic, with 4 gonopores. Genital plate 2 projecting to the rear. Anterior ambulacrum narrow and very slightly depressed; pore-pairs small, simple isopores. Other ambulacra narrow and more or less flush (interradial zone slightly raised). Petals closing distally. In posterior petals the terminal plates are occluded. The anterior petals forming an obtuse angle. Periproct on short vertical truncate face. Peristome wider than long; kidney-shaped, but labrum not projecting. Phyllodes moderately well developed. Labral plate elongate and narrowing to posterior; extending to third ambulacral plate. Sternal and episternal plates relatively narrow so that plastron is slender; suture apparently convex towards anterior; plastron densely tuberculate. Episternal plates much smaller than sternal plates but forming the rear portion of the plastron. Well-developed shield-shaped subanal fasciole (at least 3 ambulacral plates enclosed). Narrow peripetalous faciole also present. Primary tubercles within peripetalous fasciole; confined to posterior columns of anterior and lateral interambulacra.
Distribution	Miocene, Cuba.
Name gender	masculine
Type	L. jacksoni Lambert & Sanchez Roig, 1924, p. 449, by original designation.
Species Included	Only the type species
Classification and/or Status	Spatangoida, Micrasterina, Macropneustidae. Monotypic; Probably a junior subjective synonym of Trachypatagus Pomel, 1869.
Remarks	Distinguished from both Metalia and Plagiobrissus which it superficially resembles, in having an elongate labral plate that extends to the third adjacent ambulacral plate. Closest to Trachypatagus and differing from the type species only in having a narrower, shield-shaped subanal fasciole and a narrower plastron. Kier, P.M. 1984. Fossil spatangoid echinoids of Cuba. Smithsonian Contributions to Paleobiology 55, 1-336. Sanchez Roig, M. 1926. Contribucion a la Paleontologia Cubana: Los Equinodermos Fosiles de Cuba. Boletin de Minas, Habana 10, 1-179, pls 1-43.