Family Diapleuridae Ijima, 1927

Abstract

Diapleuridae Ijima (Hexactinellida, Lychniscosida) consists of a single genus, Scleroplegma Schmidt, with two species. Restudy of most known specimens of Schmidt’s Scleroplegma lanterna (preoccupied Auloplegma lanterna) confirms that it is congeneric with Ijima’s type genus Diapleura. Diapleura thus becomes a junior synonym of Scleroplegma, but Ijima’s family name, Diapleuridae, is maintained following ICZN rules. The family is distinguished from the other living lychniscosidan family, Aulocystidae, by basic construction – interpretable either as a thick-walled cup with schizorhyses or as a radial set of branching and anastomosing tubules sharing fused walls. Lychnisc dictyonalia of Diapleuridae are not arranged in rectangular array or in ranks as in Aulocystidae. Loose spiculation of Scleroplegma, first described here, is similar to that of Aulocystidae. The two species are tropical in distribution, S. lanterna restricted to the West Indies, and S. maasi restricted to Indonesia. Depth range is 204–585m, excluding a questionable record of 1383m