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
Zanclea giancarloi
Boero, Bouillon and Gravili, 2000
Fig. 48
A–E
See Schuchert (2010) for a complete synonymy.
Material examined.
HCUS-S 053p and HCUS-S 053m (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp and medusa stages.
Description
(based on our own observations;
Gravili
et al.
1996
as
Zanclea
sp.; Boero
et al.
2000; Schuchert 2010):
FIGURE 48.
Zanclea giancarloi
:
A
, hydranth;
B
, cnidome of hydroid, comprising undischarged stenoteles of two sizes and undischarged and discharged macrobasic euryteles of two sizes;
C
, newly released medusae (same scale as E);
D
, cnidome of medusa comprising undischarged stenoteles of two sizes, undischarged and discharged macrobasic euryteles from cnidophores and undischarged microbasic euryteles (?) from exumbrella (same scale as B);
E
, adult female medusa (modified after Boero
et al.
2000). Scale bars: A, 1.0 mm; B, D, 10 µm; C, E, 0.5 mm.
Hydroid.
Hydrorhiza reticular; colony stolonal; hydrocaulus as hydranth pedicel, covered by slightly corrugated perisarc; hydranths cylindrical, elongated; with 4–8 oral capitate tentacles in one whorl; 50–60 aboral capitate tentacles scattered over the whole hydranth body; medusa buds in clusters among tentacles in the lower third of the hydranth. Colours: perisarc brownish, hypostome whitish, hydranth transparent, gastric wall pinksalmon.
Habitat
type
.
The colonies have been found in depths from nearly the water surface to
30 m
(
Gravili
et al.
1996
; this study).
Substrate.
The polyps of this species grow on a variety of substrates, including Bryozoa, where colonies grow under the skeleton of the bryozoan host, algae, sponges, concretions, rocks.
Seasonality.
In Salento waters,
Z. giancarloi
occurs from June to September (Boero
et al.
2000), November–July (De Vito 2006; this study), January–June, September (
Gravili
et al.
1996
; Boero
et al.
2000; C. Gravili unpublished observations).
Reproductive period.
In Salento waters, fertile colonies occur from August to September (
Gravili
et al.
1996
; Boero
et al.
2000).
Medusa.
Adult. Mature medusa short-lived (matures within 5 days), not much different from young one, tentacles and manubrium longer, gonads interradial, females with
2 eggs
per quadrant.
Developmental stages. Newly released medusa almost spherical; with 4 perradial, oval nematocyst patches containing stenoteles on exumbrella; manubrium tubular, simple, spanning about half of the subumbrellar cavity; 4 radial canals, well visible, no linear swellings; without visible gonads; 4 marginal bulbs, one opposite pair large, the other very small; each large bulb bearing one long, tapering, contractile tentacle with cnidophores, cnidophores all on one side of tentacles, contractile, each with usually 3–5 macrobasic euryteles, distally with long cilia.
Cnidome.
Stenoteles of two sizes in tentacle capitations; apotrichous macrobasic euryteles of two sizes, both with shaft coiled along the long axis of capsule, the larger ones with spines for one fifth of their length when extruded, the smaller ones with spines for one tenth of their length, both present in hydrorhiza and hydranth body (polyp); two size classes of stenoteles; telotrichous macrobasic euryteles in cnidophores; very rare microbasic euryteles may be on exumbrella.
Distribution.
Mediterranean Sea to Bay of Biscay (Boero
et al.
2000; Bouillon
et al.
2004;
Gravili
et al.
2008a
; Schuchert 2010).
Records in Salento.
Rare in the following localities: S.ta Caterina, Ionian Apulian coast (
Gravili
et al.
1996
as
Zanclea
sp.;
Miglietta
et al
. 2000
); La Strea, Porto Cesareo (
Faucci & Boero 2000
); Otranto (De Vito 2006; Gravili 2006;
Gravili
et al.
2008a
;
Piraino
et al.
2013
; this study).
Remarks.
The whole life cycle was examined in the present study. As remarked by
Gravili
et al.
(1996)
, the hydroid of
Z. giancarloi
is similar to that of
Z. costata
, but the two species differ in cnidome and host (a bryozoan instead of a bivalve). The two
types
of macrobasic euryteles in the
Z. giancarloi
hydroid are a distinctive character, readily differentiating the species.
References.
Gravili
et al.
(1996)
as
Zanclea
sp.; Boero
et al.
(2000),
Faucci & Boero (2000)
,
Miglietta
et al
. (2000)
, Bouillon
et al.
(2004), De Vito (2006), Gravili (2006),
Gravili
et al.
(2008a)
, Schuchert (2010),
Piraino
et al.
(2013)
.