Agelas spp.

Łukowiak, Magdalena, Pisera, Andrzej & Stefanska, Tetiana, 2019, Uncovering the hidden diversity of Paleogene sponge fauna of the East European Platform through reassessment of the record of isolated spicules, Acta Palaeontologica Polonica 64 (4), pp. 871-895 : 882

Agelas spp.

Fig. 4L–N .

Material.—Upper Eocene, south-central Ukraine.

Remarks. —The long verticillate oxeas illustrated on Fig.4L, M belong to Agelas . These spicules are equipped with 18 whorls of short tubercles regularly arranged along the spicule. They are similar with acanthoxeas of modern species of Agelas , especially A. axifera Hentschel, 1911 and A. sansibarica Perino and Pronzato in Manconi et al., 2016. These two species have in their skeletons verticillated oxeas of almost identical morphology (compare Hentschel 1911: fig. 54 and Manconi et al. 2016: fig. 3). The spicules illustrated by Ivanik (2003) seem to exhibit a greater resemblance to spicules of A. sansibarica as they are of comparable length and possess a similar number of whorls.

There is also one verticillate style ( Fig. 4N ) with regular whorls of tubercles that could be assigned to one of the Agelas species (compare spicules of Agelas ceylonica Dendy, 1905 , illustrated by Manconi et al. 2016: fig. 11e).

Figures

Fig. 4. Spicule morphotypes from south-central Ukraine; Russkie Tiŝki, middle Eocene (A, O), Nikol’skoe, upper Eocene (B, C), Kantemirovka, middle Eocene (D), Melovoe, upper Eocene (E), Staroverovka, middle Eocene (F), Kantemirovka, upper Eocene (G, I), Markovka, upper Eocene (H, N), Pogonovka borehole, upper Eocene (J, L, M), Markovka, middle Eocene (K, P, T), Kiselevka, middle Eocene (Q), Lipcy, middle Eocene (R), and Kiselevka, upper Eocene (S). A. Protriaene. B, C. Anatriaenes. D. Centrotylote oxea. E–H. Amphitriaenes. I–K. Acanthotriods. L, M. Verticillate oxeas. N. Verticillate style. O–R, T. Acanthoxeas. S. Sanidaster. After Ivanik (2003); modified.