PLINTHOSELLIDAE Schrammen, 1910

Pisera, Andrzej, 2000, New species of lithistid sponges from the Paleogene of the Ukraine, Zoosystema 22 (2), pp. 285-298 : 293

Family PLINTHOSELLIDAE Schrammen, 1910

REMARKS

Plinthosellidae Schrammen, 1910 , in which dermalia occur in the form of siliceous discs, are usually regarded by paleontologists as Tetracladina and often compared with the Recent genus Neopelta Schmidt. The genus Neopelta has also dermal siliceous discs, but smooth monocrepid desmas. It had been included in the Neopeltidae Sollas, 1888 and defined as “Rhabdosa in which ectosomal spicules are monocrepid discs” (Sollas 1888). Based on their monocrepid desmas, Neopeltidae are regarded by Lévi & Lévi (1988) and Lévi (1991) as Dicranocladina Zittel. Lévi (1991) expressed some doubts concerning tetracladine nature of desmas in Plinthosella . The adult strongly tuberculated desmas in my material may pose doubts about their real nature (tetracrepid versus monocrepid) as no axial canal can be observed. Young desmas from my specimen display tetractine geometry. Despite this they are still very different from typical young tetraclones (tetracrepid desma). For these reasons I prefer to leave the question of subordinal attribution of Plinthosella open, until detailed re-evaluation of this problem can be based on more material. Plinthosellid sponges were first described from the Upper Cretaceous of Germany (Schrammen 1910) and then from France (Moret 1926) and Poland (Hurcewicz 1966). More recently, their abundant presence in the Eocene of the USA was reported, without description, by Finks (1986).