7thISS - Book - Porifera Research.pdf - Porifera Brasil - UFRJ

18Fig. 4: Ordovician spongespicules. A-E. Calcarean anddemospongid spicules from theLower-Middle Ordovician of theSan Juan Precordillera (Mehland Lehnert 1997). CEGH-UNC 15951. A. Sardospongiacynodonta. B. Calcarean triactine.C. Demospongid oxea. D-E.Dodecaactinella oncera. F-Q.Spicules from the Ponón TrehuéFormation, San Rafael Block(Beresi and Heredia 2000). F.Octactine spicule shows the distaland two of the tangential raysbroken. G. Octactine spicule.H. The proximal-distal verticalray shows a prominent node.I. Monaxon spicule appears tohave been sheared diagonally bydiagenetic processes. J. Calcareantriactine. K-Q. Scanningelectron microscope (SEM)photomicrographs. K, M, N, P.Octactine spicules. L. monaxonspicule shows the central circularcanal. O, Q. Hexactine spicules.The following species have been identified: Laocoetis sp.,Laocoetis procumbens and Laocoetis parallela (HexactinosidaSchrammen, 1903, Family Craticulariidae Rauff, 1893) (Fig.5C-J); Cribrospongia sp., Cribrospongia clathrata andCribrospongia cucullata (family Cribrospongiidae Roemer,1864) (Fig. 5A-B) and Polygonatium sp. (LyssacinosidaZittel, 1877).Sponges belonging to the Family Cribrospongiidae arecup-shaped (Cribrospongia reticulata), tubular and conical.Only a few specimens are triangular in shape and compressed(Cribrospongia cucculata). Fragments of cylindrical totubular sponges belong to the genus Laocoetis (=CraticulariaZittel, 1877; emend. Schrammen, 1937).Cretaceous freshwater sponge from the NorthPatagonian MassifThe only freshwater sponge was described from LowerCretaceous lacustrine sediments of the Chubut River Valley,in the Chubut Province, North Patagonian Massif (Fig. 1B).The sponge was determined as Palaeospongilla chubutensisby Ott and Volkheimer (1972). The encrusting sponge belongsto the monogeneric family Palaeospongillidae Volkmer-