Alien bryozoans in the eastern Mediterranean Sea — new records from the coast of Lebanon
Author
Harmelin, Jean-Georges
text
Zootaxa
2014
2014-12-09
3893
3
301
338
journal article
10.11646/zootaxa.3893.3.1
8d8dd34e-6ba4-4c54-99ff-b34de0978996
1175-5326
250297
015E59F7-6450-40E4-81C8-B09024D4C7BA
Thalamoporella harmelini
Soule, Soule & Chaney, 1999
(
Fig. 1
A–E;
Table 2
)
Thalamoporella harmelini
Soule, Soule & Chaney, 1999
: 35
, figs 51–53.
Thalamoporella gothica
var.
indica
:
Powell 1969a
: 159
, fig. 3; d’Hondt 1988: 193, figs 3–6. Non
Thalamoporella indica
Hincks, 1880
: 380
, pl. 16, fig. 1.
Thalamoporella indica
:
Chaney
et al
. 1989
: 348
(part);
Bitar & Kouli-Bitar 2001
: 72
. Non
Thalamoporella indica
Hincks, 1880
: 380
, pl. 16, fig. 1.
Material examined.
Specimens from
Lebanon
: 1) Stn 13A, a large (now fragmented), erect, bilaminar, foliaceous colony from which a fragment sent by JGH to D. Soule and J. Soule was designated as the
holotype
of
T. harmelini
[
AHF
(SBMNH-AHF) Bryozoan No. 248:
Soule, Soule & Chaney 1999
]; the rest of this colony is deposited at
MNHN
and
NHMUK
; 2) Stn 13B, a medium-sized erect, bilaminar, foliaceous colony; 3) Stn 15A, 3 encrusting unilaminar colonies on shells.
Description.
Colony encrusting, unilamellar (young stages), or ‘eschariform’, i.e. with irregularly anastomosing, bilamellar, foliaceous ramifications (older stages). Autozooids quadrate, arranged in linear rows. Frontal cryptocyst finely granular, with 30–60 small pseudopores, depressed at level of opesiules; these paired, bearing some small denticles on their distal margin, unevenly sized, the larger descending to the basal wall where its insertion forms a closed loop downwardly oriented and variably sized within colonies. Orifice generally as long as broad, poster concave, slightly granular, with two minute hooked condyles at each end, an inner, distal rim corresponding to proximal border of distally adjacent zooid. Paired adoral tubercles present, larger in older zooids. Avicularia relatively small (Az L/Av L = 1.4: ratio of mean values), longer than broad, rostrum pointed, raised on a bulging chamber at an angle of about 30°, sides a little convex, opesia semicircular, proximal cryptocyst with some tiny granules. Spicules are medium-sized callipers and compasses. Ovicells lacking in the
holotype
and other specimens.
TABLE 2.
Thalamoporella harmelini
, morphometrics of three colonies from Stns 13A, 13B, 15A.
T. harmelini
|
X |
SD |
Range |
N |
Az L |
563 |
51 |
450–650 |
30 |
Az W |
293 |
31 |
245–365 |
30 |
Or L |
144 |
14 |
120–165 |
28 |
Or W |
143 |
9 |
120–155 |
28 |
Av L |
390 |
51 |
315–510 |
25 |
Av W |
211 |
60 |
140–330 |
25 |
Remarks.
Thalamoporella harmelini
belongs to a group of species with acute avicularian mandibles (
Soule
et al
. 1999
). It is seemingly closely related to
Thalamoporella floridana
(
Osburn, 1914
)
from the eastern Caribbean and Florida,
Thalamoporella spinosa
Chaney, Soule & Soule, 1989
from the Indian Ocean and Persian Gulf, and
Thalamoporella labiata
(
Levinsen, 1909
)
from
Taiwan
Strait. These four species have similarly shaped pointed avicularia, single closed-loop basal insertions and apparently no ovicells. Both
T. spinosa
and
T. labiata
differ from
T. harmelini
in having orifices with a convex proximal lip. In
T. floridana
, the basal-loop insertions are clearly shorter than in
T. harmelini
and the proximal lip of the orifice is smooth instead of being granular.
The genus
Thalamoporella
includes 46 Recent species (
Bock 2014
), distributed in warm to warm-temperate waters of the Indo-Pacific realm (80%) and the W and E Atlantic (17.4%).
Thalamoporella harmelini
was the only
Thalamoporella
species recorded in the Mediterranean, exclusively from the Levant coasts. The figures and descriptions of specimens recorded from
Israel
as
Thalamoporella gothica
(Busk)
var.
indica
Hincks, 1880
by
Powell (1969a)
and d’Hondt (1988) suggest that they are conspecific with
T. harmelini
. In particular, as pointed out by
Powell (1969a)
, they have acute avicularia, no ovicells and their colonies are either encrusting or bilamellarfoliaceous. The occurrence of this species in
Israel
was confirmed by Noga Sokolover (pers. comm.
12 December 2013
). Two other records of
T. indica
from the Eastern Mediterranean (
Chaney
et al
. 1989
;
Bitar & Kouli-Bitar 2001
) correspond to Lebanese specimens from the present collection, assigned here to
T. harmelini
. The known geographical range of
T. harmelini
is restricted to a limited portion of the Levantine basin, from Tel Aviv to Beirut, i.e. in the vicinity of large commercial ports, close to the Suez Canal. Conversely, despite large-scale sampling it was not recorded at other sites along the Lebanese coast. It is a typical cryptogenic species but its distribution argues for an exotic origin.