LOWER CARBONIFEROUS BRYOZOA 
Stenophragmidium sp. Figs 80-83 
MATERIAL. BELUM K3436, K15209-K15215 (5 zoarial frag- 
ments and 2 longitudinal sections), Upper part of the Glencar 
Limestone (Viséan, Asbian), Sillees River, County Fermanagh. 
DESCRIPTION. Zoaria consist of large erect hollow expansions up 
to 11.17mm in width, or thin encrusting adnate sheets 0.28—0.30mm 
thick. Autozooecia are budded from a very thin undulating basal 
wall. Autozooecial chambers are recumbent in the thin endozonal 
region (0.15 mm) and straight in the wider exozone (0.28 mm). The 
vestibule lies at a high angle of 80° to 85° to the zoarial surface, and 
is moderately wide (0.19-0.20 mm). 
Autozooecial walls are 0.03—0.04 mm thick in the endozone, but 
expand rapidly in the exozone to between 0.15 and 0.18 mm. They 
are usually of constant width, occasionally undulatory, and rarely 
-moniliform. Walls consist of a well defined central hyaline zone 
(0.02 mm wide) in which laminae are orientated parallel to the 
growth direction. Thin lateral laminae are derived from this central 
zone and bend sharply proximally. This is typical leioclemid-type 
wall structure (after Boardman 1960). 
Up to three hemiphragms are developed within and at the base of 
the exozone, where they arise from proximal walls. They are thin, 
often straight and occasionally bend slightly proximally. They are 
|short (0.04—0.07 mm in length), usually extend less than half-way 
‘into chambers, and have rounded bulbous tips. 
Autozooecial apertures are polygonal or irregular in shape, occa- 
\sionally circular and are closely spaced at less than one diameter 
apart Apertures decrease in diameter away from monticules. 
Interapertural walls are rounded and moderately thick, with as many 
as 16 stylets occurring along their crests. 
Large acanthostyles (0.05—0.07 mm) are usually found at 
autozooecial wall junctions, with smaller stylets (0.02—0.03 mm) 
between. Exilazooecia are rare; they are small, with circular to 
angular apertures. They occur as isolated individuals between 
autozooecia, or infrequently in groups of 10 to 12 in monticule- 
centred maculae which are widely spaced at up to 5.53 mm apart. 
DISCUSSION. This taxon is known from 14 specimens from which 
details of both external and internal structure are known. It does not 
resemble previously described British species, but may be 
synonomous with Tabulipora crassimuralis Lee, 1912. The genus 
ieeds revision, which will be undertaken at a future date and until 
hen I prefer to leave this taxon unassigned to any species. 
The hollow portions of the zoaria examined all had a posthumous 
ig. 83 Stenophragmidium sp. Line drawing of external features of 
BELUM K15209; a, Portion of hollow ramose colony, scale bar = | 
mm; b, detail of autozooecia and exilazooecia and disposition of 
acanthostyles, scale bar = 0.1 mm. 
155 
Table 27 Measurements of Stenophragmidium sp. (in mm). N=6. 
NM Xx Mn Mx CVw CVb 
ZD 39 7.92 4.81 11.17 11.28 4.38 
Zl 60 WB) 5 10 12.08 13.44 
Z2 60 5):9) 4 8 13739) 6.16 
AD 60 0.24 0.15 0.32 10.75 10.84 
IWT 60 0.07 0.04 0.12 20.86 7.96 
ED 60 0.08 0.06 0.15 21.26 125) 
It 4 0.64 0.25 1.07 10.60 1.22 
WB 4 1.64 0.90 2.76 16.76 1.68 
IMS 6 4.45 3.38 5.5) 18.34 14.30 
infill of micritic mud which was also found in autozooecial cham- 
bers. Zoaria possibly encrusted soft algal branches which have now 
disappeared, or may simply have been hollow. 
STRATIGRAPHICAL RANGE. Lower Carboniferous (Viséan, Asbian). 
DISTRIBUTION. Ireland, North Wales. 
Order CYSTOPORATA Astrova, 1964 
Suborder FISTULIPORINA Astrova, 1964 
Family FISTULIPORIDAE Ulrich, 1882 
Genus FISTULIPORA M ‘Coy, 1849 
TYPE SPECIES. Fistulipora minor M‘Coy, 1849 by subsequent 
designation (Milne-Edwards & Haime 1850: lix) from the Lower 
Carboniferous of the British Isles. 
Fistulipora incrustans (Phillips, 1836) 
Figs 84a, 85-88, 105 
A complete systematic description, full synomony and discussion of 
the type specimens is given in Bancroft & Wyse Jackson (1995). 
MATERIAL. BMNH PD9651-9676, 9740; TCD.34088-34103, 
34138-34139, 34146, 34157, 34159, 34166, 42590, 42610; BELUM 
K2151,K2153, K2193, Upper part of the Glencar Limestone (Viséan, 
Asbian), Carrick Lough, County Fermanagh. TCD.42511, Upper 
part of the Glencar Limestone (Viséan, Asbian), Sillees River, 
County Fermanagh. 
DESCRIPTION. Zoaria form thin unilaminate button-like discs up to 
1.3cm in diameter; encrusting unilaminate or multilaminate sheets 
up to 1.58mm thick, or small chaetetiform nodular expansions 
30mm wide by 17mm high. Colonies often encrust crinoid stems, 
fenestellid Bryozoa, and occasionally brachiopod valves. 
Autozooecia are budded from a very thin basal wall (0.015—0.025 
mm thick). They are often initially slightly recumbent, but subse- 
quently become erect and orientated at 80° to 90° to the zoarial 
surface. Autozooecia are straight, tubular and thin walled. Thin 
diaphragms are commonly developed at the base of chambers and 
are less common and irregularly dispersed throughout the remaining 
portions of chambers. Autozooecia are arranged in straight to curved 
rows which produces an offset pattern on the zoarial surface. 
Autozooecial apertures are large (0.17mm to 0.40mm); usually 
circular to oval, occasionally D-shaped, rarely sub-polygonal in 
shape and spaced 1—2.5 diameters apart. Lunaria are indistinct and 
not consistently present. They are small — only one fifth the circum- 
ference of apertures, crescent-shaped, marginally elevated above the 
zoarial surface, and discretely indent apertures (by as much as 
0.04mm). Lunaria are found on the proximal sides of autozooecia 
closest to monticules. In a few zoaria lunaria completely encircle 
autozooecial apertures, forming low peristome-like collars. Rarely, 
