Casearia Quenstedt, 1858

Nose, Martin, Vodrážka, Radek, Fernández, Luis-Pedro & Méndez-Bedia, Isabel, 2014, First record of chambered hexactinellid sponges from the Palaeozoic, Acta Palaeontologica Polonica 59 (4), pp. 985-996 : 989-990

Genus Casearia Quenstedt, 1858

Type species: Spongia articulata Schmidel, 1780 . Reid (2004) erroneously indicated Scyphia articulata Goldfuss, 1826 as the type species of the genus (Senowbari-Daryan and Zankl 2010), Franconian Alb, southern Germany; Late Jurassic.

Emended diagnosis.—Cylindrical to top-shaped or open, funnel-shaped hexactinosidans in which body consists of a superimposed series of hemispherical to annular or discoidal growths, usually with a common, paragastral cavity; dermal surface may be constricted transversely at segment junctions; skeletal surfaces may be formed by tangential networks of ankylosed stauractines, interpreted as dermalia and gastralia; stauractine network of outside, continuous to paragastral margin at top of body, and extending through wall to paragastral surface between each segment; ostia and postica of radial canals, arranged quadrately in some examples under surface networks.

Remarks.—The studied specimens correspond to the diagnosis in Kolb (1910: 186) and Reid (2004: 486) for the genus Casearia . Minor differences in skeletal organization, including the poorly developed exhalant canals and the absence of paratangential network formed by fused stauractines (e.g., Müller 1974), cannot be regarded as diagnostically significant for the discrimination of these fossils from Casearia . Moreover, also some other Casearia species do not posses tangential networks formed by ankylosed stauractines (dermalia and gastralia) on the skeletal surfaces (e.g., Casearia pamirica [ Boiko, 1990], C. alpina Senowbari-Daryan and Zankl, 2010 ). For this reason, which was neglected by earlier authors, the genus diagnosis has been slightly emended herein (compare with Reid 2004).

Casearia was first described from the Upper Jurassic of Germany ( Quenstedt 1858; Zittel 1878; Kolb 1910; Müller 1974, 1990). Later, Boiko 1990; Wu 1990; Rigby et al. 1998; Senowbari-Daryan and Hamadani 1999; Senowbari-Dary- an and Zankl 2010; and Senowbari-Daryan and Amirhassankhani 2012 reported Casearia species (including the synonyms Innaecoelia and Monilispongia ) also from the Jurassic of Tadjhikistan and Upper Triassic of the Pamir Range, Sichuan / China, Iran, and the Northern Calcareous Alps. Other valid genera such as Dracolychnos , Caucasocoelia , Pseudoverticillites , and Esfahanella differ from the Early Devonian fossils from northern Spain in several respects, as follows.

Pseudoverticillites exhibits low, empty chambers, which are of regular size and shape, contrasting the higher chambers of irregular shape with skeletal filling of dictyonal hexactine network in the fossils from Spain. The chambers of Caucasocoelia are also regular in size and shape, and thus differ from the chambers of the sponge described here. Moreover, Caucasocoelia is characterized by a considerably larger axial spongocoel, and wider hexactinosidan meshes. In addition, the character of the skeletal chamber filling differs from that seen in Casearia . Both genera have been described by Boiko (1990) from the Upper Triassic (Norian–Rhaetian) of Russia (northern Caucasus). Dracolychnos from the Upper Triassic (Carnian) of China / Sichuan exhibits a different funnel-shaped morphology ( Wu and Xiao 1989) and also differs from Casearia with regard to the character of the spiculation of the dermal and gastral surfaces. Esfahanella from the Upper Triassic of Iran ( Senowbari-Daryan and Amirhassankhani 2012) is distinguished from Casearia mainly by its very wide spongocoel.

Stratigraphic and geographic range.—Early Devonian (Cantabrian Mountains, NW Spain); Late Triassic (Pamir, Iran, China, central Europe); Jurassic ( Germany, Tadjhikistan).