The sponge genus Ephydatia from the high-latitude middle Eocene: environmental and evolutionary significance.

Renata Manconi,Peter A. Siver,Alexander P. Wolfe,Andrzej Pisera

doi:10.1007/s12542-016-0328-2

Abstract

The freshwater sponge species Ephydatia cf. facunda Weltner, 1895 (Spongillida, Spongillidae) is reported for the first time as a fossil from middle Eocene lake sediments of the Giraffe kimberlite maar in northern Canada. The sponge is represented by birotule gemmuloscleres as well as oxea megascleres. Today, E. facunda inhabits warm-water bodies, so its presence in the Giraffe locality provides evidence of a warm climate at high latitudes during the middle Eocene. The morphological similarity of the birotules to modern conspecific forms suggests protracted morphological stasis, comparable to that reported for other siliceous microfossils from the same locality.

Highlights

Kurzfassung Die rezente Sußwasserschwamm-Art Ephydatia cf. facunda Weltner, 1895 (Spongillida, Spongillidae) wird erstmals als Fossil aus den mittel-eozanen Seeablagerungen des Giraffe Kimberlit-Maars im nordlichen Kanada nachgewiesen
Marine sponges have existed since the Proterozoic (Pisera 2006; Van Soest et al 2012), the earliest freshwater sponges do not appear in the fossil record until the Permo-Carboniferous of Europe (Schindler et al 2008)
The sponge microfossil record from the Giraffe locality comprises a wide array of loose spicules, including numerous megascleres, gemmuloscleres, and microscleres

Summary

Introduction

Kurzfassung Die rezente Sußwasserschwamm-Art Ephydatia cf. facunda Weltner, 1895 (Spongillida, Spongillidae) wird erstmals als Fossil aus den mittel-eozanen Seeablagerungen des Giraffe Kimberlit-Maars im nordlichen Kanada nachgewiesen. Middle Eocene (*40 Ma) lake sediments within a kimberlite diatreme in northern Canada, referred to as the Giraffe locality, have yielded a rich assemblage of siliceous microfossils, including diatoms (Bacillariophyceae), chrysophytes (Chrysophyceae and Synurophyceae), euglyphids (Euglyphidae, Rhizaria), and spongillids (Pisera 2010; Siver et al 2010; Pisera et al 2013, 2014). Many of these forms have pronounced affinities with modern taxa (Siver and Wolfe 2005, 2009). We report additional spicules from the Giraffe locality that belong unambiguously to the genus Ephydatia Lamouroux, 1816 (family Spongillidae)

Methods

Results

Discussion

Conclusion