Thecocodium brieni Bouillon, 1967

Gravili, Cinzia, Vito, Doris De, Camillo, Cristina Gioia Di, Martell, Luis, Piraino, Stefano & Boero, Ferdinando, 2015, The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide, Zootaxa 3908 (1), pp. 1-187 : 47-48

Thecocodium brieni Bouillon, 1967

Fig. 31 A–D

See Schuchert (2009) for a complete synonymy.

Material examined. HCUS-S 0 36 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Bouillon 1967; Brinckmann-Voss 1970; Edwards & Harvey 1983; Schuchert 2009, 2012):

Hydroid. Hydrorhiza as an irregular network of anastomosing stolons, enclosed in thin perisarc; colonies stolonal, small, polymorphic; gastrozooids bottle-shaped, pink coloured, naked; hypostome opaque white; without tentacles; dactylozooids tubular, elongated, translucent colourless with white capitula, more numerous than gastrozooids, without internal cavity or apical orifice, with 4–5 capitate apical tentacles, retractile; gonozooids similar to gastrozooids from which they develop when one single gonophore grows from the near the base of polyp. Gonophores, as fixed sporosacs; males (styloid type) a simple bulbous evagination of body wall, females with vestiges of radial canals forming 4 pouches around the spadix; occasionally female gonophores also containing spermatogonia, several oogonia develop, but usually only 2 mature eggs that develop to planula in situ. Colours: stolons and gastro-gonozooids pink, hypostomes white, dactylozooids colourless with white capitula.

Cnidome. Microbasic euryteles, discharged shaft about as long as capsule; desmonemes with relatively long capsules.

Habitat type. Rocky cliffs, in depths of 2–200 m ( Brinckmann-Voss 1970; Calder 1998; Schuchert 2009).

Substrate. Concretions and other substrates such as stones, rocks, oyster shells, calcareous tubes of polychaete worms, algae, tunics of ascidians, sponges and at the base of Muricea sp. (Octocorallia).

Seasonality. In the Ligurian Sea ( Boero & Fresi 1986) in November; in Salento waters in February and November (De Vito 2006; Piraino et al. 2013; this study).

Reproductive period. In the Ligurian and Tyrrhenian Seas, fertile colonies occur from April to November ( Brinckmann-Voss 1970; Boero & Fresi 1986).

Distribution. Eastern and western North Atlantic, Mediterranean ( Bouillon 1967; Brinckmann-Voss 1970; Edwards & Harvey 1983; Boero & Fresi 1986; Calder 1998; Bouillon et al. 2004; Gravili et al. 2008a; Schuchert 2009).

Records in Salento. Rare at S.ta Caterina ( Miglietta et al. 2000), and Otranto ( Miglietta et al. 2000; De Vito 2006; Gravili 2006; Gravili et al. 2008a; Piraino et al. 2013; this study).

Remarks. The dactylozooids of Thecocodium brieni are used both for defense and for food capture. Nutritive hydranths stretch out and bend over prey-laden dactylozooids, picking up the food ( Brinckmann-Voss 1970; Edwards & Harvey 1983; own observations).

References. Bouillon (1967), Brinckmann-Voss (1970), Edwards and Harvey (1983), Boero and Fresi (1986), Calder (1988), Miglietta et al. (2000), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Gravili et al. (2008a), Schuchert (2009, 2012), Piraino et al. (2013).

Figures

FIGURE 31. Thecocodium brieni: A, colony with dactylozooids and gastrozooids; B, gonozoid with gonophore; C, dactylozooid; D, nematocysts (B, C same scale bar) (drawn by C. G. Di Camillo). Scale bars: A, 0.2 mm; B, C, 0.1 mm; D, 15 µm.