BRYOZOANS FROM CHATHAM ISLAND 
shields are less coarsely perforated, and opesiae/orifices are mono- 
morphic and semicircular. Ovicells are lacking and, although 
characteristic small avicularia occur distally to the orifices, they do 
not occur on every zooid. Lutetian-Bartonian Poropeltarion 
Cheetham (type species P lebanonense Cheetham, 1963) has 
frondose to narrow-branched bilamellar colonies of pseudoporous 
zooids. Both avicularia and ovicells are lacking. Recent Promicroa 
d’Hondt & Gordon, 1998 from the Norfolk and Kermadec Ridges in 
the Southwest Pacific produces erect, narrow-branched colonies, but 
these are unilamellar and the zooids have both semicircular orifices 
and ovicells; there are no avicularia. In the sum of the limited 
number of characters available, the Chatham Island specimen most 
closely resembles species of Poropeltarion, or possibly Punctu- 
riellina. 
Family ONYCHOCELLIDAE Jullien, 1882 
Genus INVERSARIA von Hagenow, 1851 
TYPE SPECIES. Ceriopora tubiporacea Goldfuss, 1826, subse- 
quent designation by Gregory, 1899; Upper Maastrichtian, Maas- 
tricht, The Netherlands. 
Inversaria gondwanae sp. nov. Figs 45-47 
IGNS BZ 187-1, from Pukekio Hill, Chatham Island. 
IGNS BZ 187-2, 3. NHM BZ 4782, 4783 (sample). 
HOLOTYPE. 
PARATYPES. 
NAME. Alluding to the first record of the genus in a part of former 
Gondwana. 
DESCRIPTION. Colony erect, stout, irregularly branching, attached 
by a somewhat thickened base not greater than 4 mm in maximum 
width or diameter. Wide-angled bifurcations are usual but, as at a 
rare anastomosis of branches in a colony, 34 branches may origi- 
nate; each branch pair of a bifurcation is in the same plane but other 
bifurcations are in other planes. Branches more or less cylindrical, 
ranging (among the broken fragments available) from 0.74—3.27 
mm diameter, widening to ca. 4.5 mm before the widest bifurcation. 
Autozooids in 9-11 regularly alternating longitudinal series, increas- 
ing to 20 such series immediately proximal to a bifurcation; zooid 
outlines defined by shallow interzooidal grooves, diamond-shaped 
with four sides and widest at the lateral points or the distal and 
proximal and/or lateral points truncated so that the shape is unevenly 
6-8 sided; often wider (0.46—0.63 mm across the width of the 
diamond) than long (0.37—0.58 mm). Zooidal cryptocyst evenly 
granular in the best-preserved example, sloping, initially shallowly 
then steeply, all around the opesia which is more distally placed, 
with a straighter proximal rim, in neanic zooids and centrally placed 
and circular in ephebic zooids with thicker frontal calcification. 
Opesial-peristomial shaft of equal longitudinal diameter, sloping 
inwards proximally and widening from 0.15 mm at the level of the 
primary orifice to 0.20 mm at the frontal opening. Simple 
avicularium-like heterozooids may occur between zooids in a longi- 
tudinal series (i.e., between the lateral points of adjacent zooids in 
transverse rows); more or less circular or transversely oval with a 
small concentric foramen. Ovicells not seen frontally or in section. 
REMARKS. Jnversaria is a relatively little-known genus, originally 
attributed to the Cyclostomata. Voigt and Williams (1973) reviewed 
the known species, described them, and gave stratigraphic ranges 
and geographic distributions as follows: 
I. tubiporacea (Goldfuss, 1826), Campanian-Maastrichtian, ?Danian, 
The Netherlands, Belgium, Germany. 
21 
I. crassipes (Marsson, 1887), Lower Maastrichtian, Germany, Den- 
mark, Poland. 
I. flabellula (von Hagenow, 1846), Upper Campanian, Sweden. 
I. ramosissima (Eichwald, 1865), Upper Maastrichtian, Lower 
Danian, Crimea, Ukraine. 
I. trigonopora von Hagenow, 1851, Upper Maastrichtian, Belgium, 
The Netherlands. 
I. tuber Voigt & Williams, 1973, Upper Maastrichtian, The Nether- 
lands. 
I. verrucosa Voigt, 1962, Upper Maastrichtian, Crimea, Ukraine. 
Colonial morphology among these species ranges from mounded, 
through erect and branching to bilamellar-foliaceous. Cryptocystal 
morphology is relatively similar throughout the species, which all 
have deep peristomial shafts. Calcified opercula and occlusor mus- 
cle scars have been preserved in some material of the type species 
(Voigt & Williams 1973). The present species most closely resem- 
bles J. crassipes in colonial and zooidal morphology, but has 
more-regularly arranged zooids in narrower branches and smaller, 
simpler avicularia. 
The Chatham Island species is the youngest in the genus, extend- 
ing its Upper Campanian-Lower Danian range by ca. 5 MY, and the 
first record outside Europe. 
Genus CHONDRIOVELUM Hayward & Thorpe, 1988 
TYPE SPECIES. Labioporella adeliensis Livingstone, 1928, by 
original designation; Recent, Antarctica. 
Chondriovelum fossilis sp. nov. Figs 48-52 
HOLOTYPE. IGNS BZ 188-1, from Pukekio, Chatham Island. 
PARATYPES. IGNS BZ 188-2, 188-3, 188-4, 188-5. 
DESCRIPTION. Colony erect, dichotomously branching, the stems 
more-or-less cylindrical except for a slight flattening at a bifurca- 
tion, 0.44—0.76 mm in diameter, being widest before a bifurcation. 
Zooids more-or-less alternating, in 6-8 longitudinal series, the 
larger number occurring before a bifurcation, reducing to 6 immedi- 
ately after. Autozooids relatively elongate, length = 0.44—-0.74 mm, 
width = 0.20-0.32 mm, the boundaries marked by narrow grooves 
between adjacent raised cryptocystal margins. Cryptocyst shallow, 
sloping to the opesia-orifice, the imperforate surface lightly reticu- 
lated in the best-preserved zooids. Opesia-orifice wider (0.11—0.19 
mm) than long (0.07—0.13 mm), more-or-less bean-shaped with the 
middle part of the proximal rim slightly projecting as an inverse 
crescent, the ends of which appear as denticles. Large avicularia 
occasionally present, shorter than autozooids but occupying their 
place in a longitudinal series, with the autozooid distal to an 
avicularium longer and/or wider than other autozooids; the rostrum 
acute, with an area of palate encircling a longitudinally oval palatal 
foramen that is separated by a bridge of calcification from a tiny 
circular opesial foramen; proximal end of the avicularium truncate, 
the boundary slightly curved around the proximal autozooid. Ovicells 
not definitely seen; one zooidal orifice has a distal depression 
occluded with debris but its nature is equivocal. 
REMARKS. The generic placement of this species is problematic. 
The shape and size of the opesia-orifice and the equivocal ovicellular 
depression are indicative of a cellariid affinity; on the other hand, 
some onychocellids can have relatively small opesiae. The large 
avicularium is very similar to that seen in Recent Chondriovelum 
adeliense (Livingstone) and C. angustilobata (Moyano) (family 
Onychocellidae) from Antarctica and magellanic South America, 
