Merlia sp.

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 : 886

Merlia sp.

Fig. 6L .

Material.—Upper Eocene, south-central Ukraine.

Remarks. —The small oval, ring-shaped spicule called clavidisc shown on Fig. 6L can be assigned to one of the species of Merlia . Four recent species of Merlia are distinguished and three of them, M. normani Kirkpatrick, 1908 , M. tenuis Hoshino, 1990 , and M. deficiens Vacelet, 1980 , possess clavidiscs. The spicule that is illustrated here can be assigned to one of these species or its close relatives. It is worth noting that Merlia is characterized by basal calcareous skeleton that was not found in these deposits. Similar calvidiscs, not associated with basal calcareous skeleton, are known since the Early Jurassic ( Wiedenmayer 1994).

Figures

Fig. 6. Spicule morphotypes from south-central Ukraine; Russkie Tiŝki, Middle Eocene (A, H, O, Y, Z), Kiselevka, upper Eocene (B, C), Markovka, middle Eocene (D), Russkie Tiŝki, upper Eocene (E), Kiselevka, upper Eocene (F, G, M), Pogonovka borehole, upper Eocene (I), Markovka, upper Eocene (J, K, N), Nikol’skoe, upper Eocene (L, P), Grigorevka borehole, upper Eocene (Q, R, S, T), Melovoe, upper Eocene (U, V), and Kiselevka, middle Eocene (W, X). A. Spherostyle. B–D. Tylostyles. E, F, I–K, M. Acanthostyles. G, H. Exotyles. L. Clavidisc. N, O. Acanthoxeas. P–R. Acanthostrongyles. S, T. Sigmas. U, V. Anisochelae. W. Isochela. X. Spheraster. Y, Z. Tylotes. After Ivanik (2003); modified.