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
Mitrocoma annae
Haeckel, 1864
Fig. 85
A–D
See
Kramp (1961)
for a complete synonymy.
Material examined.
HCUS-S 0 93 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula)—polyp stage.
Description
(based on our own observations; Kramp 1932a, 1957b):
Hydroid.
Hydrorhiza linear, creeping; colony stolonal; hydranths with conical hypostome; 12–16 filiform tentacles in a single whorl, without basal intertentacular membranous web; hydrothecae
Cuspidella
-like, cylindrical, wide, elongated, sessile, arising at irregular intervals from hydrorhiza; operculum pyramidal, with numerous sharp, pointed, triangular flaps meeting centrally, with no clear limits with the hydrotheca. Gonothecae scarcely pedicellate, on hydrorhiza, four times larger than the hydrotheca, with numerous sharp, pointed, triangular flaps meeting centrally, with few medusae (2–3) per gonotheca (F. Boero unpublished observations on material from the Ligurian Sea).
Habitat
type
.
Rocky and/or biogenic banks (depth range:
0–90 m
) (
Boero & Fresi, 1986
; Morri
et al.
1999).
Substrate.
Algae and hydroids.
Seasonality.
September–February (
Boero & Fresi 1986
) in the Ligurian Sea; January–February (Brinckmann-
Voss 1987
) in the Tyrrhenian Sea; October–November (
Denitto 1996
) in the Ionian Sea; September (Mastrototaro
et al.
2010); March (this study)
Reproductive period.
February (
Boero & Fresi 1986
) in the Ligurian Sea.
Medusa.
Adult. Umbrella flatter than a hemisphere,
30–40 mm
wide, mesoglea thick; manubrium very small,
1/8–1/10
of umbrella diameter; mouth lips fairly short; radial canals and circular canal narrow; gonads linear, sinuous, along distal 1/2–3/4 of radial canals, not reaching circular canal, with a median division; 60–100 conical marginal bulbs; each marginal bulb with one wrinkled marginal tentacle; 3–8 marginal cirri between successive marginal tentacles; 60–100 open statocysts.
Developmental stages. New born medusa with umbrella almost spherical, manubrium very small, 1/3 of subumbrellar cavity, 4 mouth lips; 4 radial canals; 4 perradial tentacular bulbs (2 largers than the others); 4 perradial tentacles (2 longer than the others); 4 cirri between successive marginal tentacles; 4 statocysts.
FIGURE 85.
Mitrocoma annae
:
A
, general view of a colony;
B
, hydrothecae;
C
, part of colony with hydrotheca and gonotheca;
D
, newly liberated medusa (drawn by F. Boero). Scale bars: B, 0.1 mm; C, 250 µm; D, 0.5 mm.
Cnidome.
Atrichous and basitrichous haplonemes.
Distribution.
Endemic of Mediterranean Sea (Bouillon
et al.
2004;
Gravili
et al
. 2008a
).
Records in Salento.
Rare at: S.ta Maria al Bagno (
Denitto 1996
;
Miglietta
et al.
2000
; Gravili 2006;
Gravili
et al
. 2008a
); Porto Cesareo (
Faucci & Boero 2000
); S. Maria di Leuca (Mastrototaro
et al.
2010).
Remarks.
Metschnikoff (1886a)
reared the hydroid of this medusa. Gonothecae and medusae not seen in the present study.
References.
Kramp (1932a, 1957b, 1961),
Boero & Fresi (1986)
,
Brinckmann-Voss (1987)
,
Benović & Lučić (1996)
, Morri & Bianchi (1999),
Faucci & Boero (2000)
, Bouillon
et al.
(2004), Gravili (2006),
Gravili
et al
. (2008a)
, Mastrototaro
et al.
(2010),
Bianchi
et al.
(2011)
.