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
?
Chartella
sp.
(
Figs 23–27
,
Table 7
)
Material examined.
SMF
40.024, locality VH-97-315.
Description.
Encrusting and very delicate colony, forming a small patch. Autozooids large, rhomboidal or hexagonal, vertical walls very thin and lightly calcified, interzooidal communication via several mural septula per zooid; basal walls only marginally calcified. Spines absent. Operculum small, having only a marginal sclerite. Avicularia small, interzooidal, situated between subsequent zooids in a row; cystid quadrangular, both, palatal foramen and posmandibular opesia are semicircular and separated by two small condyles, surrounded by narrow smooth cryptocyst; rostrum and mandible semicircular, directed distolaterally.
Ovicells and ancestrula not observed.
Remarks.
Only one encrusting colony, consisting of about 20 zooids, is present in our material. Zooidal morphology resembles that of
Chartella barleei
(
Busk, 1860
)
, which is occasionally placed in the genus
Terminoflustra
, mainly owing to the position and morphology of the avicularia. However, usually only the erect part of the bilaminar branching colonies of
C. barleei
are described (e.g.
Hayward & Ryland 1998
;
Kluge 1975
) while virtually nothing is known about its encrusting portion.
Prenant & Bobin (1966, p. 189)
described it as a simple lamina similar to a membraniporid colony, which does not shed much light on the problem. We therefore only doubtfully assign this species to the genus
Chartella
.
When
Álvarez (1992)
described a similar encrusting species from shallow waters of the Strait of
Gibraltar
, he pointed out that there are some differences in zooid size of
C. barleei
from different regions. While
Prenant & Bobin (1966)
recorded relatively small zooids of around
0.4 mm
in mean length from the Mediterranean Sea,
Álvarez (1992)
measured a mean of c.
0.6 mm
in the
Gibraltar
specimens, whereas
Hayward & Ryland (1998)
reported a zooid size between 0.72 and
1 mm
, which is identical to zooids of the present specimen.
Specimens from the Bay of Biscay, occurring between 340 and
630 m
, were identified by d’Hondt (1973) as
Terminoflustra
aff.
barleei
. The only difference between these specimens and our material as well as
C. barleei
sensu
stricto
is the shape of the avicularia, which are more elliptical in the Bay of Biscay specimens. The zooid measurements from the erect colony part given by d’Hondt (1973) are similar to those from the Galicia Bank but no information about the encrusting portion was provided. Thus, in the light of these problems, and because only a single small specimen without ovicells was found, we have to leave the taxon in open nomenclature.
TABLE 7.
Measurements (in mm) of?
Chartella
sp.
Mean |
SD |
Minimum |
Maximum |
N |
Autozooid length |
0.884 |
0.0751 |
0.765 |
0.997 |
14 |
Autozooid width |
0.678 |
0.0954 |
0.524 |
0.842 |
14 |
Avicularium cystid length |
0.247 |
0.0286 |
0.212 |
0.279 |
6 |
Avicularium cystid width |
0.251 |
0.0422 |
0.190 |
0.305 |
6 |
Avicularium frontal area length |
0.177 |
0.0189 |
0.162 |
0.210 |
6 |
Avicularium frontal area width |
0.123 |
0.0254 |
0.106 |
0.173 |
6 |
SD, standard deviation; N, number of measurements.