Erect bifoliate species of Microporella (Bryozoa, Cheilostomata), fossil and modern
Author
Martino, Emanuela Di
A7905C48-FF37-4D27-BCCE-F0560AF040A2
Natural History Museum, University of Oslo, Norway.
e.d.martino@nhm.uio.no
Author
Taylor, Paul D.
7AFF2929-DF5B-46B2-94E6-B26B396CC2C8
Departments of Earth and Life Sciences, Natural History Museum, London, United Kingdom.
p.taylor@nhm.ac.uk
Author
Gordon, Dennis P.
DD9C0F3A-8512-4AC8-B395-7687CE3FC565
National Institute of Water & Atmospheric Research, Wellington, New Zealand.
dennis.gordon@niwa.co.nz
text
European Journal of Taxonomy
2020
2020-07-02
678
1
31
journal article
21572
10.5852/ejt.2020.678
57a241fd-5993-4064-b152-b00ee0a46e2a
3928412
C230401F-3AD1-43D8-9C82-1DEDF5CF40FD
Microporella
sp
.
1
Fig. 12
;
Table 9
Material examined
NEW ZEALAND
• Single infertile fragment;
SW of South Island
,
Puysegur Bank
; [
46.43° S
,
166.08° E
]; depth
187 m
; Recent;
NHM-UIO
BLEED 151
(voucher specimen)
.
Description
COLONY. Erect, bifoliate, branches narrow; fragment available ca
3 mm
wide with up to six linear series of alternating zooids on each side; interzooidal communications through multiporous septula visible at colony growing edge.
AUTOZOOIDS. Distinct with interzooidal boundaries marked by thin band of slightly raised calcification on either side of a narrow grooVe, rounded rectangular to hexagonal, longer than wide (mean L/W = 1.31). Frontal shield conVex, pustulose, the pustules flat-topped, Varying in size; marginal areolae numbering about 10–12, usually elongate (
25–40 µm
long) especially at zooidal corners, sometimes indistinguishable from frontal pores along lateral sides of the zooids; non-marginal pseudopores about 40–60, small (diameter
10–15 µm
), irregularly scattered among pustules, sometimes coalescent.
ORIfICE. TransVersely D-shaped, significantly wider than long, hingeline with about 14–18 equal-sized teeth; oral spines lacking. Operculum smooth.
ASCOPORE fIELD. As a narrow band of gymnocystal calcification, at approximately same leVel as orifice but beneath leVel of adjacent frontal shield, located at ca
55–75 µm
from the orifice hingeline, separated from it by non-porous pustulose cryptocyst; circular (diameter
50–60 µm
) to transVersely elliptical (
55 µm
long by
80 µm
wide), opening C-shaped, 10 ×
50 µm
, with tiny radial denticles, and a circular tongue projecting from the distal edge.
AVICULARIUM. Usually single, rarely paired, moderately large, present in all autozooids, positioned at level with the ascopore, oriented distolaterally, usually at about 45° to the long axis of the supportive autozooid; crossbar calcified; opesia semielliptical; rostrum short, subtriangular with concaVe sides, the distal end rounded, distinct channel present. Mandible
150–180 µm
long, narrow and pointed. Multiple intramural buds observed in avicularia.
OVICELLS. Not observed.
Remarks
Among all bifoliate congeners,
Microporella
sp. 1 mostly resembles
M. hyadesi
. The two species share a transVersely D-shaped orifice with equal-sized teeth in the hingeline, the characters of the ascopore and the appearance of the frontal shield made of flat-topped pustules. Differences include: the shape of the zooids (mean L/W = 1.67 and 1.31, respectiVely) which are rectangular and flat in
M. hyadesi
, rhomboidal to hexagonal and convex in
Microporella
sp. 1; the avicularium is more laterally oriented and has a wider channel in the rostrum than
M. hyadesi
. The two species also differ in their geographical distributions. The single available fragment of
Microporella
sp. 1 was found at Puysegur Bank, south west of South Island of
New Zealand
at a depth of
187 m
, while
M. hyadesi
is a South Atlantic species found at a depth of
49–341 m
(
Hayward & Ryland 1990
).