Clionaidae d’Orbigny, 1851

Łukowiak, Magdalena, 2015, Late Eocene siliceous sponge fauna of southern Australia: reconstruction based on loose spicules record, Zootaxa 3917 (1), pp. 1-65 : 23

Family Clionaidae d’Orbigny, 1851

In the studied material there are numerous mucronate tylostyles found ( Figs. 10 A–C). These spicules, with clubshaped shaft and the other end pointed, resemble in their morphology those of the Recent clionaid Cliona mucronata Sollas, 1878 (compare, i.e. with Calcinai et al. 2005; figs. 4f, i; and Figs. 12 A, B). However, the described here fossil mucronate tylostyles are much bigger (about 900 µm) and more slender than those described by Calcinai et al. (2005) from the Indo-Pacific Ocean and those noted by Vacelet & Vasseur (1971) from Madagascar (that exceed 100 µm in length). There are no other present-day sponges having this very characteristic type of spicule recognized anywhere else in the world. The most adjacent area to the north of Australia from where C. mucronata is noted is the Banda Sea ( Topsent 1897; van Soest et al. 2013).

The spicules belonging to the family Clionaide have already been described from the geological record (for more details see Wiedenmayer 1994) but this is the first fossil occurrence of Cliona cf. mucronata .

Very characteristic, about 300–500 µm long, verticillate acanthostrongyles found in the studied material ( Figs. 10 S–Y) are here also assigned to hadromerids. The cylindrical, curved shafts of these acanthostrongyles are rounded at the tips that are microspined. The whole spicule is covered with spirally coiled rows of tubercles. The number of whorls of tubercles over the spicule may vary from 10 to 19. The large variability in number of the whorls and in size of these spicules may suggest that they belong to more than one species, or that they belong to a species with a high intraspecific variability of these spicules. Another single verticillate acanthostrongyle-like spicule ( Fig. 31 M) may be also related to the mentioned acanthostrongyles, however not without doubts. This type of verticillate acanthostrongyles was described for the first time by Carter (1880) from Gulf of Manaar and was assigned to the excavating clionaid Dotona pulchella Carter, 1880 (see also Topsent 1904, pl.12, fig. 2B and Fig. 11 ). Today, sponges of this species are recorded only from the Azores and India (van Soest et al. 2013). There is also another Dotona — D. davidi ( Kirkpatrick, 1900; described as Dyscliona davidi ) that inhabits today South Pacific Ocean and possess similar scleres. However, its spicules do not have microspined tips (compare with Kirkpatrick 1900, pl. 14, fig. 1E).

There are also very similar spicules in other demosponge genera, heteroxyid Halicnemia verticillata ( Bowerbank, 1866) , reported from the Azores and coelosphaerid Paracornulum atoxa Vacelet, Vasseur & Lévi, 1976 [now Zyzzya fuliginosa ( Carter, 1879b) ; compare with pl. 28, fig.9; described as Suberites fuliginosa ] recorded from Tulear as well as Zyzzya papillata Thomas 1966 noted from South India and Sri Lanka (van Soest et al. 2013; compare with Thomas 1968 fig. 6B; described as Damirina papillata ). In all of these cases spicules possess sculptured heads but are less regularly spined and the spicules of clionaid Dotona pulchella most resemble those described here.

This spicule morphotype has already been described as fossils by Mostler from the Jurassic of the Alps (1990, pl. 1, fig. 15). This same author also described similar spicules from the Lower Carboniferous and Permian (1994; pl. 3, figs. 13–16), but attributed them to agelasids. Similar spicules are also described from the Cretaceous by Schrammen (1924, pl. 4.19). Verticillate strongyles are also known from the Miocene of the Bahamas ( Bukry 1978, pl. 13, fig. 4) and from the Late Eocene of Norseman, Australia ( Hinde 1910, pl. 1, fig. 10), from the same deposits as studied here. Dotona pulchella , however, has never been described from fossil material before.

Figures

FIGURE 10. Spicules of sponges of the order Hadromerida; A – C—Mucronate tylostyles of Cliona cf. mucronata, family Clionaidae; D – F—Tylostyles of the order Hadromerida; G, H—Tylostyles of Terpios sp., family Suberitidae; I, J, P, R—Anthasters of Diplastrella cf. megastellata, family Spirastrellidae; K – M—Spherostyles of Sphaerotylus sp. 1, family Polymastiidae; L – O—Spherostyles of Sphaerotylus sp. 2, family Polymastiidae; Q—Microsclere spiraster of family Spirastrellidae or Clionaidae; S – Y—Verticillate strongyles of Dotona pulchella Carter, 1880, family Clionaidae.

FIGURE 11. Verticillate acanthostrongyle of Dotona pulchella (redrawn from Calcinai et al. 2001).

FIGURE 12. Spicules of recent representants of the order Hadromerida; A—Subtylostyle of Cliona mucronata (redrawn from Calcinai 2005); B—subtylostyle of Cliona mucronata (redrawn from Vacelet & Vasseur 1971); C—Club-shaped spicules of Sphaerotylus vanhoeffeni (described as S. capitatus; redrawn from Hentschel 1914; size from 504 to 1080 µm).

FIGURE 31. Other demosponge spicules and their hypothetical assignment; A—Strongyle-like spicule of unidentified sponge; B – F—Different types of fusiform spicules of unidentified sponge; G; H—Styles of unidentified sponge; I—Club-shaped spicule of unidentified sponge; J, K—Rhabdostyles of unidentified sponge; L—Comma spicule of unidentified sponge; M—Sculptured, acanthostrongyle-like spicule of unidentified sponge.