Systematics and diversity of deep-water Cheilostomata (Bryozoa) from Galicia Bank (NE Atlantic)
Author
Souto, Javier
Author
Berning, Björn
Author
Ostrovsky, Andrew N.
text
Zootaxa
2016
4067
4
401
459
journal article
46900
10.11646/zootaxa.4067.4.1
4d2bf7a6-415a-4fb2-8c8f-12b79f8a400a
1175-5326
257945
1CC5D0E7-0B60-4E62-BACD-9775931ED7F9
Galiciapora unica
n. sp.
(
Figs 114–118
,
Table 20
)
Material examined.
Holotype
:
MNCN
25.03/3976, locality DR04.
Paratypes
:
MNCN
25.03/3977, locality DR01;
MNCN
25.03/3978, locality DR02;
MNCN
25.03/3979, 3980, locality DR03; OLL 2015/919, locality DR03; OLL 2015/920, locality DR01.
Etymology.
Latin
unicus
, only, single, alluding to the single zooids in uniserial chains.
Description.
Colony encrusting, uniserial, branching at an angle of c. 40–50°. Zooids oval, large, frontal shield convex with smooth surface texture, entirely covered by about 150 pseudopores right up to prominent, widely flaring peristome, distal part of peristome not formed in ovicellate zooids; vertical walls not developed laterally, but 2 distolateral basal pore-chambers present, well-marked by raised borders, each with paired communication pores from which 1–2 zooids may be budded on either or both sides; central distal area in between has single pore through which communication with ooecium-producing distal kenozooid is established when budded. Orifice a little longer than wide, widest in distal third, anter roughly horseshoe-shaped, proximal margin with broad, shallow U-shaped sinus, condyles rather small, smooth. Peristome thick-walled, flared, with paired lateral adventitious avicularia.
Avicularia adventitious, small, paired, incorporated into lateral rim of peristome, oval in outline, rostrum semielliptical, directed distolaterally, crossbar complete, without columella, palatal foramen and postmandibular opesia rounded, the latter smaller, both with cryptocystal shelf.
Ovicell terminal, prominent; ooecium formed by flat distal kenozooid budded from distal uniporous pore chamber of maternal zooid, longer than wide; ectooecium smooth, frontally flattened with 25–30 pseudopores of variable shape and size, proximal area concave, paralleling margin of zooidal orifice, lateral margins abutting peristome.
An ancestrula not observed.
TABLE 20.
Measurements (in mm) of
Galiciapora unica
n. sp.
Mean |
SD |
Minimum |
Maximum |
N |
Autozooid length |
1.152 |
0.1372 |
1.024 |
1.349 |
7 |
Autozooid width |
0.766 |
0.0664 |
0.682 |
0.845 |
7 |
Orifice length |
0.183 |
0.0141 |
0.161 |
0.200 |
6 |
Orifice width |
0.158 |
0.0158 |
0.138 |
0.182 |
6 |
Avicularium length |
0.076 |
0.0100 |
0.067 |
0.093 |
5 |
Avicularium width |
0.060 |
0.0069 |
0.053 |
0.070 |
5 |
Ooecium length |
0.331 |
0.0174 |
0.311 |
0.343 |
3 |
Ooecium width |
0.373 |
0.0078 |
0.368 |
0.382 |
3 |
SD, standard deviation; N, number of measurements
Remarks.
This species is yet another uniserial encrusting ascophoran cheilostome described from bathyal depths.
As
in many of the other uniserial species, and in contrast to multiserial species from shallow waters, the zooids are relatively large, the lateral walls are greatly reduced and the ooecium is formed by a distal kenozooid, not by a distal autozooid. These characters have seemingly evolved as adaptations for bathyal conditions independently in numerous clades as the uniserial growing species are distributed over different superfamilies. It is also possible that many have a long evolutionary history as it is often difficult or impossible to determine sister taxa. The systematic position of uniserial ascophorans is therefore often fairly isolated, leading to the existence of several monspecific genera [e.g.
Nimbella
with
N. limbata
Jullien & Calvet, 1903
;
Sertulipora
with
S. guttata
Harmelin & d'Hondt, 1992
;
Cheilonellopsis
with
C. inflata
Gordon, 2014
;
Placidoporella
n. gen.
with
P. insperata
(Jullien, 1882)
].
Sertulipora guttata
was described from the
Gibraltar
Strait region based on four specimens designated as a
holotype
and three
paratypes
(Harmelin & d’Hondt 1992). Later, Tricart & d’Hondt (2009) indicated another
paratype
with the number MNHN-19792 from the Bay of Biscay. This designation is invalid because the location and specimen were not included in the original description; further, examination of the specimen showed that it is not
S. guttata
and could belong to the genus
Galiciapora
. A detailed study of the specimen is required, however, to come to a definite conclusion about its specific identity.
Galiciapora unica
was found at five stations between
1138 and
1697
m depth, encrusting corals and rocks.