Taxonomic notes on some Cheilostomata (Bryozoa) from Madeira
Author
Berning, Björn
text
Zootaxa
2012
3236
36
54
journal article
10.5281/zenodo.211022
fc7d5cb4-2741-48de-b2c9-940d17bd6bab
1175-5326
211022
Stephanollona contracta
(
Waters, 1899
)
(
Figs 29–32
,
Table 6
)
Lepralia contracta
Waters, 1899
: 11
, pl. 3, figs 4–6;
Norman 1909
: 306
, pl. 41, figs 5, 6.
Stephanollona contracta
:
Souto
et al.
2010
: 18
, fig. 15.
Material examined.
Lectotype
:
MMF
42044a (here designated), the larger colony fragment on a slide; material from Madeira, collected by J.
Y
. Johnson, colony free of substratum (no further information provided as to exact location or depth).
Paralectoype
:
MMF
42044b, the smaller colony fragment on the same slide as
holotype
, also free of substratum. Other:
NHMUK
2011.9.1.4, Madeira, near Funchal, colony encrusting a piece of coal, Norman collection (no further information provided as to exact location or depth);
NHMUK
2011.9.1.5, from the same suite as previous specimen, colony encrusting a piece of coal.
TABLE 6.
Measurements (in µm) of
Stephanollona contracta
..
ZL ZW OL OW OvL OvW oAL oAW spAL spAW mean 462 361 129 112 181 243 77 65 265 105 SD 45
37 5 4
14
19 6 3
9 9 min. 411 297 121 103 163 200 67 60 252 89 max. 554 459 137 122 215 273 85 70 285 123
n 20 20
20
20 12
12 12 12
12 12
Remarks.
A description of
Stephanollona contracta
is not given here because the species was only recently redescribed in detail by
Souto
et al.
(2010)
. However, there are some additional remarks to be made, based on observations of the type-specimen: 1) owing to advanced secondary calcification of the proximal ooecial margin, in ontogenetically older zooids the fenestra in the ooecium may be rather crescentic (
Figs 29, 30
), whereas the relatively young Portuguese specimen shows only semicircular fenestrae; and 2) the anter may be variable in shape, ranging from a shallow and only slightly concave proximal orificial margin to a more deeply U-shaped anter within the same colony (
Fig. 31
).
FIGURES 29–32.
Stephanollona contracta
(Waters, 1899)
.
29
, surface of mature colony showing several spatulate avicularia (lectotype, MMF 42044a).
30
, close-up of proximal ovicell (paralectotype, MMF 42044b).
31
, zooids at the colony growth margin; note differences in anter shape (arrows) (NHMUK 2011.9.1.4).
32
, primary orifice (NHMUK 2011.9.1.4). Scale bars: Fig. 29, 31 = 200 µm; Fig. 30 = 40 µm; Fig. 32 = 20 µm.
Another issue can be solved here.
Souto
et al.
(2010)
mentioned that the
type
material of
S
.
contracta
, which was originally deposited in the
MMF
, had seemingly been lost. However, for reasons that will be explained in more detail elsewhere, part of a loan of bryozoan specimens by the
NHMUK
during the 1960s were not returned to Madeira and remained in London (M. Spencer Jones, pers. comm. 2011), among them the
types
of
Saevitella peristomata
and
Stephanollona contracta
described and figured here. After examination of the remaining specimens with the VP SEM in London, the material will finally be returned to the
MMF
.
As
with
Plesiocleidochasma porcellanum
,
Stephanollona contracta
is another putative species with a near-circumglobal record (cf.
Cook 1964
, and references therein), and in need of revision. The specimen from southern
Portugal
described and figured by
Souto
et al.
(2010)
marked the first true record of this species on the European continental shelf.