146 
EXTERNAL 
Z2 
IMS 
INTERNAL 
Fig. 59 Measurements taken on trepostomes in this study: ZD = Zoarial 
diameter measured perpendicular to growth direction; IMS = Inter- 
monticule spacing; AD = Autozooecia apertural diameter: maximum 
value seen in aperture; [WT = Interzooecial wall thickness; ED = 
Exilazooecia apertural diameter: maximum value seen in aperture; MD 
= Mesozooecial apertural diameter: maximum value seen in aperture; 
Z1 = Number of complete autozooecial apertures enclosed in 1mm*; Z2 
= Number of complete autozooecial apertures measured along a 2mm 
line; AR = Axial ratio: this measures the ratio of the exozone to the 
zoarial diameter [AR = 2(TE)/ZD; the method employed follows that of 
Boardman (1960: 21) rather than that of Cuffey (1967: 31) who 
multiplied the ratio by 100, which makes the obtained values 
unnecessarily large]; ET = Endozone thickness; TE = Exozone 
thickness; FD = Diameter of ring septum foramen. 
and Hederella may have grown over adead skeleton ofRhombocladia 
lying face downwards on the sea-bed. Rhombocladia may have hadan 
encrusting habit as some Carrick Lough specimens show that the 
zoarium grew around and engulfed some adjacent pinnate bryozoan 
colonies. The perpendicular attitude of these pinnate colonies, which 
grew erect, relative to colonies of Rhombocladia, suggests that 
Rhombocladia grew horizontally on or just above the sea-bed. 
Table 20 Quantitative measurements for all described species of Rhombocladia (in mm). 
P.N. WYSE JACKSON _ 
STRATIGRAPHICAL RANGE. Lower Carboniferous (Tournasian | 
[Courceyan]—Viséan [Brigantian]). 
DISTRIBUTION. British Isles (Counties Cavan, Fermanagh, Kil-| 
dare, and Tyrone, Ireland; Mill Gill, North Yorkshire, England). | 
Order TREPOSTOMATA Ulrich, 1882 
Suborder HALLOPOROIDEA Astrova, 1965 
Family HETEROTRYPIDAE Ulrich, 1890 
Genus LEIOCLEMA Ulrich, 1882 
TYPE SPECIES. Callopora punctata Hall, 1858, by original desig- 
nation from the Lower Carboniferous of Iowa, U.S.A. 
Leioclema indentata sp.nov. Figs 60-62 
HOLOTYPE. BMNH PD9621, Upper part of the Glencar Lime- 
stone (Viséan, Asbian), Carrick Lough, County Fermanagh. 
PARATYPES. BMNH PD9564, 9622-9626; TCD.34065-34066 
34123, Upper part of the Glencar Limestone (Viséan, Asbian)| 
Carrick Lough, County Fermanagh. TCD.42550, Upper part of the 
Glencar Limestone (Viséan, Asbian), Sillees River, County Ferman: 
agh. TCD.28152, Base of reef, Lower Carboniferous (Viséan 
Asbian), Shanvaus Cross, County Leitrim, G.D. Sevastopulo Col} 
lection. 
DERIVATION OF TRIVIAL NAME. From the indentation of the 
autozooecial apertures by acanthostyles. 
DIAGNOSIS. Leioclema forming ramose erect cylindrical, irregu_ 
larly dichotomising zoaria. Zooecial walls considerably thickene¢ 
in exozone. Diaphragms present at zooecial bend. Mesozooeci: 
common between chambers in exozone, closed to the surface 
Autozooecial apertures indented by several large acanthostyles. 
DESCRIPTION. Zoaria are robust, composed of straight, cylindricé 
I 
branches 1.15 to 2.13 mm in diameter. Branches are circular 1 
cross-section and bifurcate at irregular intervals. There is a sligh 
increase in branch diameter prior to division; subsequent branche 
are slightly narrower. The largest fragment examined measures 24.) |. 
mm long. 
ZW ZT AR AD1 AD2 AS 
R. dichotoma (M‘Coy,1844) 1.79 0.47 7-12 0.27 0.12 0.07-0.14 
R. aktashensis Laurentjeva, 1985 1.50-1.80 1.00-1.1 6-8 0.22-0.24 0.12 0.10-0.15 
R. borissiaki Shulga-Nest., 1955 1.00-1.35 0.45-0.50 7-8 0.26—-0.34 0.12-0.14 - 
R. carnica Ceretti, 1964 0.60 - - 0.30 0.13 0.09-0.10 
R. coronata Shulga-Nest., 1955 1.10 0.45 6-8 0.19-0.20 0.08-0.15 0.20-0.27 
R. delicatula Rogers, 1900 1.50 0.52 10 0.26 0.15 0.10 
R. johnseni Ceretti, 1964 1.07 0.50 7 0.20 0.21 0.09 
R. kasimovensis Shulga-N., 1955 0.80-1.20 0.45-0.70 5-7 0.15-0.22 0.08-0.12 - 
R. minor Crockford, 1944 0.46-0.57 - 2-3 0.24-0.29 0.10-0.15 = 
R. multispinosa McKinney, 1972 1.4 <1.00 9 0.30-0.42 0.12-0.19 - 
R. ninae Shulga-Nest., 1955 1.70-2.30 0.70-0.80 8-9 0.20-0.22 0.10-0.12 0.22-0.28 
R. orientalis Lu, 1989 - 0.30-0.50 - 0.22 0.16-0.18 - 
R. punctata Dunaeva, 1961 1.00-1.08 0.48 - 0.24—0.27 0.12 - 
R. ramosa Gorjunova, 1988 1.10-1.32 0.86-0.88 6-7 0.18-0.22 - - 
R. septata Shulga-Nesterenko, 1955 1.25 0.45-0.52 il 0.27-0.32 0.12-0.14 0.15-0.20 
R. spinulifera Crockford, 1944 0.70-0.95 - 4-6 0.19-0.24 0.16 - b 
R. tenuata Shulga-Nesterenko, 1955 0.80 0.50 7 0.18—0.20 0.10-0.12 - Lal 
Data from original sources. 
