Potamophloios canadensis Pisera, Siver, and Wolfe, 2013

Pronzato, Roberto, Pisera, Andrzej & Manconi, Renata, 2017, Fossil freshwater sponges: Taxonomy, geographic distribution, and critical review, Acta Palaeontologica Polonica 62 (3), pp. 467-495 : 484

Potamophloios canadensis Pisera, Siver, and Wolfe, 2013

Fig. 17 .

Type horizon: Lutetian, middle Eocene.

Type locality: Giraffe Kimberlite maar, Northern Canada (64°44’ N, 109°45’ W) .

References: Pisera et al. 2013.

Description (emended from Pisera et al. 2013).—Megascleres. Strongyles with highly variable size (7.90–30.9 × 3.12–5.0 μm), smooth, thick, often curved, or otherwise slightly irregular, frequently with inflated tips. Microscleres presumed) smooth strongyles. Gemmuloscleres not detected. No whole intact gemmules.

Remarks.—Pisera et al. (2013) report that a possible attribution to the genus Corvospongilla must to be excluded because of the lack of typical microscleres and gemmuloscleres belonging to this genus in all examined samples. Potamophloios canadensis is the oldest record belonging to the family Potamolepidae , of which the present geographic range is quite exclusive from Africa and South America with spot-like enclaves in the southern Nearctic Region, Thailand, and Oceanic Islands, i.e., Fiji and New Caledonia. Its presence in North Canada is consistent with the recent discovery of a living new potamolepid genus Cherokeesia Copeland, Pronzato, and Manconi 2015 and species ( Cherokeesia armata ) from the Tennessee, and the fact that during the Eocene the climate of northern Canada and Nearctic Region was much warmer than today, as indicated by the presence of the redwood tree Metasequoia ( Siver and Wolfe 2009) .

Figures

Fig. 17. Potamophloios canadensis Pisera, Siver, and Wolfe, 2013, Spongillida: Potamolepidae, ZPAL Pf23; Lutetian, middle Eocene, Giraffe Kimberlite maar, Northern Canada. Strongyles (gemmuloscleres) in a wide dimensional range. Malformed spicules (bottom row). SEM images. Modified from Pisera et al. (2013).