On a collection of shallow-water hydroids (Cnidaria: Hydrozoa) from Guadeloupe and Les Saintes, French Lesser Antilles
Author
Galea, Horia R.
text
Zootaxa
2008
1878
1
54
journal article
10.5281/zenodo.184149
086e0d63-8af0-4ad1-8884-03fa56b5ea98
1175-5326
184149
?
Scandia
sp.
(fig. 5D, table 9)
Material examined
.
Stn. 3
:
26.01.2008
—two hydrothecae, no gonothecae, on alga.
Description
. Colony epiphytic, stolonal, composed of two hydrothecae of different sizes. Hydrothecal pedicel, of variable length, corrugated. Hydrotheca cylindrical, asymmetrical and bent slightly to one side; walls smooth to imperceptibly undulated; margin everted, oblique; basally, an annular thickening of perisarc. One hydrotheca has renovated margin. Gonotheca absent. Nematocysts not seen.
Remarks
. Due to its occurrence on algae and not on hydroids, this species is provisionally included in the genus
Scandia
Fraser, 1912
. No positive identification is possible in the absence of gonothecae.
Distribution
. The present material originates from
Guadeloupe
.
TABLE 9.
Measurements of?
Scandia
sp., in µm. (1)Primary hydrotheca.
Larger specimen(1) |
Smaller specimen |
Hydrotheca |
– height |
950 |
435 |
– maximum width |
441 |
272 |
– diameter at rim |
475 |
330 |
Pedicel |
– length |
423 |
377 |
– diameter |
128 |
93 |
Family
Lafoeidae Hincks, 1868
|
?
Lafoea
sp.
(fig. 5E–F, table 10)
|
Material examined
.
Stn. 6
:
23.03.2008
—several dense, sterile colonies, on
Halimeda
sp. (
MHNG
INVE
61001).
Description
. Colony stolonal, with extremely minute, individual hydrothecae arising irregularly from slender (20–30 µm wide), smooth, creeping hydrorhiza. Hydrothecae borne on short, transversely annulated pedicels (2–3 slightly marked “annuli”). Hydrotheca tubular, radially symmetrical, 165–205 µm long; walls nearly parallel, though imperceptibly widening in middle region (maximum width 50–55 µm); basally tapering into pedicel; either diaphragm or annular thickening absent; distally slightly flaring, 45–60 µm wide at aperture; margin circular, rim even; occasionally renovated once. Perisarc of hydrotheca smooth, moderately thin. Hydranth with 10–12 filiform tentacles. Gonosome unknown. Nematocysts: a few large, bean-shaped heteronemes (15.7–20.0) × (6.4–7.8) µm, most probably arranged in a belt below the tentacles; small capsules (4.8–5.1) × (1.3–1.4) µm, in tentacles.
Remarks
. This species is provisionally included in the genus
Lafoea
Lamouroux, 1821
based on the following observations: the colony has no nematothecae; the hydrotheca is long, tubular, borne on a very short pedicel; basally there is no diaphragm or annular thickening; the hydrothecal aperture is devoid of an operculum.
Although some members of
Lafoea
, e.g.
L. dumosa
(
Fleming, 1828
)
, could exhibit both stolonal and erect growth forms (sometimes simultaneously within the same colony), the present species forms exclusively stolonal colonies. Moreover, its size is much smaller than that of its presumed congeners (table 10).
Data on the nematocyst complement of the various species of
Lafoea
are scarce. Large, bean-shaped isorhizas have been reported in both
L. annulata
(Watson, 2003)
and
L. dumosa
(
Schuchert 2001a; Galea, personal observations made on Chilean material
). However, the present species is provided with heteronemes instead of haplonemes.
Distribution
. Known only from Les Saintes.