Gemellipora eburnea Smitt, 1873

Moissette, Pierre, Antonarakou, Assimina, Kontakiotis, George, Cornée, Jean-Jacques & Karakitsios, Vasileios, 2021, Bryozoan faunas at the Tortonian-Messinian transition. A palaeoenvironmental case study from Crete Island, eastern Mediterranean, Geodiversitas 43 (26), pp. 1365-1400 : 1383-1385

Gemellipora eburnea Smitt, 1873

( Fig. 10I )

Gemellipora eburnea Smitt, 1873: 35 , pl. 7, figs 152-156. — Harmer 1957: 994, pl. 69, figs 28-29. — Moissette 1988: 190, pl. 30, figs 6, 9, 12.

Gemellaria punctata – Seguenza 1880: 127, pl. 12, figs 14-14a. — Neviani 1900: 148, pl. 16, figs 89.

Pasythea eburnea – Busk 1884: 5, pl. 34, fig. 1a-f. — Canu & Bassler 1928: 151, pl. 8, figs 11-12.

OCCURRENCE. — Early Miocene: Indonesia ( Di Martino & Taylor 2014). Middle Miocene: Hungary ( Moissette et al. 2006). Late Miocene: Dominican Republic ( Cheetham et al. 1999), Algeria ( Moissette 1988), Calabria. Pliocene: Sicily ( Rosso 2002). Pleistocene: Calabria, Sicily ( Rosso & Di Geronimo 1998; Rosso 2005), Rhodes ( Moissette & Spjeldnaes 1995), Karpathos ( Moissette et al. 2017). Holocene: southern Italy ( Di Geronimo et al. 2001). Recent: western and eastern Atlantic ( Brazil, Caribbean, Azores, Madeira, Bay of Biscay, Gulf of Cadiz), Indian Ocean ( Indonesia), Pacific (Hawaii, New Zealand). This is a deep-water species found in the Atlantic at depths between 60 m and 3300 m ( Harmer 1957; Harmelin 1977).

DESCRIPTION

Cellariiform colony. Internodes made of one to four pairs of zooids. In each pair, the zooids are separated by a thin groove, placed back to back, slightly twisted from one another, and oriented at about 90 degrees of the previous/ following pair. Zooids elongate, displaying a smooth frontal surface with scarce inconspicuous pores. A few zooids bear in their central part a small oval scar (separated by the thin groove dividing two zooids) corresponding to the start of a lateral branch. Apertures almost circular with two very small indentations on the proximal corners. Neither avicularia nor ovicells.

REMARKS

Smitt (1873) describes an encrusting base ( Smitt 1873: pl. 7, fig. 152) from which the erect, typical form arises. Another creeping colony ( Smitt 1873: pl. 9, fig. 178) is erroneously attributed by the same author to G. eburnea . The confusion was evidenced by Canu & Bassler (1928).

Figures

FIG. 10. — A-C, Scrupocellaria cf. elliptica (Reuss, 1847);A, view of some zooids showing opesia with 4 spine bases on the outer distal part and 3 spine bases + 1 scutal spine on the inner distal rim, FAN36:AMPG(IV) 3587; B, zooids with 7 spine bases and the scutum, FAN35:AMPG(IV) 3586a; C, dorsal surface of a colony fragment with small vibracularia and radicular pores, FAN35: AMPG(IV) 3586b; D, E, Scrupocellaria scrupea Busk, 1852; D, ovicellate colony fragment, FAN35: AMPG(IV) 3590a; E, detail frontal view showing opesia with five spine bases, FAN35: AMPG(IV) 3590b; F-H, Cellaria salicornioides Lamouroux, 1816; F, part of a slender internode, FAN18: AMPG(IV) 3513a; G, detail view showing denticles and endotoichal ovicells, POTB13: AMPG(IV) 2821a; H, avicularia in frontal and lateral view (arrow), POTB13:AMPG(IV) 2821b; I, Gemellipora eburnea Smitt, 1873, broken internode showing two zooids with two oval scars separated by a thin interzooidal groove, CAP032: AMPG(IV) 3426. Scale bars: A-E, G, I, 100 µm; F, H, 200 µm.