The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide
Author
Gravili, Cinzia
Author
Vito, Doris De
Author
Camillo, Cristina Gioia Di
Author
Martell, Luis
Author
Piraino, Stefano
Author
Boero, Ferdinando
text
Zootaxa
2015
3908
1
1
187
journal article
42365
10.11646/zootaxa.3908.1.1
6f1d1977-6b97-4789-828c-76ed250cf1ae
1175-5326
242729
D6AD2B49-170B-4D9C-84AA-DBE0FEEAD8BE
Thecocodium brieni
Bouillon, 1967
Fig. 31
A–D
See Schuchert (2009) for a complete synonymy.
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.
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)
.