Spongillida, Manconi and Pronzato, 2002

Pronzato, Roberto, Pisera, Andrzej & Manconi, Renata, 2017, Fossil freshwater sponges: Taxonomy, geographic distribution, and critical review, Acta Palaeontologica Polonica 62 (3), pp. 467-495 : 475

Spongillida gen. et sp. indet. sensu Cayeux 1929

Fig. 9 .

Horizon: Stephanian, upper Carboniferous.

Locality: Freshwater deposits at Montgros, Gard of the Massif Central, France.

References: Cayeux 1929; Geyer 1962; Zimmerle 1991; Schindler et al. 2008.

Description (emended from Cayeux 1929: 300).—Spiculite with monaxial spicules (200–250 × 10–20 μm) typically oriented in all directions, or grouped in bunches showing a perfect parallelism with thoroughly matted spicules aligned parallel to bedding. The spicules show traces of the central axial canal.

Remarks. —The sample is reported simply as freshwater sponges spicules. We could only judge the French material from the published evidence. Schindler et al. (2008: fig. 2) show a reproduction of the two original thin sections (see also Cayeux 1929: pl. 17: 64–65). Attribution to freshwater sponges is based on geological context i.e., occurrence among coal deposits far from any marine basin/deposits. Associated sediment consists of quartz grains, phyllite clasts, rare pyrite, and an additional clay mineral. There are spots of organic matter cautiously described ( Cayeux 1929: 301) as an unknown form of sapropelitic coal.

Figures

Fig. 9. Spongillida gen. et sp. indet, sensu Cayeux (1929). Stephanian, upper Carboniferous; Montgros, Gard of the Massif Central, France. Freshwater spiculites where spicules (200–250 μm long) are horizontally arranged (A) and cross cut (B). Modified from Cayeux (1929: pl. XVII).