Geodiidae, Gray, 1867

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 : 872

Geodiidae indet.

Figs. 1C, E, J, N , 2Z .

Material.—Upper and middle Eocene, south-central Ukraine.

Remarks.—The bean-shaped to round massive microscleres with small projections tightly arranged on the spicule surface are considered to be sterrasters ( Ivanik 2003: pl. 14: 1, 2, pl. 15: 1, 2; Fig. 1C, E, J, N ). They are found in two geodiid genera, Geodia Lamarck, 1815 and Caminus Schmidt, 1862 (compare Cárdenas et al. 2011 and van Soest et al. 2014: fig. 9). The spherical microsclere ( Fig. 1B ) may also belong to one of these genera (but affinity with Placospongia Gray, 1867 or even Tethyidae cannot be ruled out as well due to poor preservation). Likewise, the big, slender mesotriaenes with a characteristic shaft protruding from the both sides ( Fig. 1K, I, V ) are probably of geodiid affinity (compare Geodia garoupa in Carvalho et al. 2016 or G. praelonga in Sim-Smith and Kelly 2015). The same is true for characteristic tetraxial spicule with a long shaft and reduced two clads ( Fig. 1W ) that may belong to some Geodia (former Isops) species. Monaxonic spicules with bulb-shaped ending called exotyles ( Fig. 5E) could be assigned to Geodia (Isops) but their vulcanellid, hadromerid, or raspailiid affinity is also possible (see Cárdenas et al. 2011). The same is true for some anatriaenes ( Fig. 1L ) and orthodichotriaenes ( Ivanik 2003: pl. 22: 3; Fig. 1M , AB) which may belong to Geodiidae , Ancorinidae , or Pachastrellidae .

Amongst the illustrated spicules the plesiaster ( Ivanik 2003: pl. 20: 2) most likely belongs to a geodiid sponge as well. However, more accurate taxonomic assignment is not possible due to the lack of characteristic features of this spicule.

Moreover, the short-shafted dichotriaene with flat, long leaf-shaped clads ( Fig. 2Z ) resembles triaenes of modern Penares Gray, 1867 , especially those of P. sclerobesa Topsent, 1904 (compare Topsent 1904: pl. 10: 13). However, also some astrophorid lithistid demosponges are characterized by similar spicule types.

Genus Erylus Gray, 1867

Type species: Erylus mammillaris ( Schmidt, 1862) , Azores Canaries Madeira, Adriatic Sea, Recent .

Figures

Fig. 1. Spicule morphotypes from south-central Ukraine; Grigorevka borehole, upper Eocene (B), Glâdov Âr, Upper Cretaceous (A, G, J), Pogonovka borehole, upper Eocene (C), Russkie Tiŝki, middle Eocene (D, F, I, O, W, X, Z, AA), Markovka, upper Eocene (E, H, N), Nikol’skoe, upper Eocene (K, L, Q, T, U, V), Pesčanoe, upper Eocene (M, AB), Kantemirovka, upper Eocene (P), Harkov region, middle Eocene (S), Verhnee, lower Eocene (R), and Staroverovka, middle Eocene (Y). A, G, H. Aspidasters. B. Spheraster. C, E, J, N. Sterrasters. D, F. Selenasters. I. Triaene. K, X. Mesotriaene. L, O. Anatriaenes. M, AB. Dichotriaenes. Q. Centrotylote?oxea. R.?Triaene. S. Plagiotriaene. P, T, U. Triaenes. V. Irregular triaene. W. Style. Y– AA. Diaenes. After Ivanik (2003); modified.

Fig. 2. Spicule morphotypes from south-central Ukraine; Čečva, lower Oligocene (A, B), Staroverovka, middle Eocene (C, L), Verhnee, lower Eocene D), Russkie Tiŝki, middle Eocene (E, H, R, Z), Nikol’skoe, upper Eocene (F, I, J, K, M, T), Černoleska, upper Eocene (G), Markovka, upper Eocene (N), Melovoe, middle Eocene (O), Glâdov Âr, Cretaceous (P), Markovka, lower Oligocene (Q), Lipcy, middle Eocene (S), Pogonovka, upper Eocene (U), Melovoe, upper Eocene (V), Pesčanoe, upper Eocene (W, Y), and Kiselevka, upper Eocene (X). A–E, G. Protriaenes. F, H, J, K, M, U, V. Anatriaenes., L, P. Prodichotriaenes. N, O. Oxeas. Q. Orthotriaene. R. Diaene. S.?Triaene. T. Orthodichotriaene. W–Y. Pinakids. Z. Dichotriaene. After Ivanik 2003); modified.