BRYOZOANS FROM CHATHAM ISLAND 
Erect tubuliporine base sp. 2 Fig. 16 
MATERIAL. NHM BZ 4776. 
DESCRIPTION. Colony base encrusting, comprising a single 
oligoserial branch, about 1 mm wide, with 5—6 autozooidal series; 
branch profile high, well-rounded; stump of a broken erect branch, 
subcircular in cross-section, present at distal end of the encrusting 
branch. Autozooids with short frontal walls, about 0.5 mm long 
by 0.25 mm wide, attaining maximum width opposite the aper- 
ture; zooidal boundary walls slightly salient; apertures subcircular, 
small, 0.09—0.10 mm in diameter; pseudopores circular. 
Gonozooids absent. 
REMARKS. This poorly-preserved specimen encrusts a pebble. 
Unlike the previous species, kenozooids do not appear to be devel- 
oped at the edges of the branch, and the branch has a much more 
robust morphology. 
Suborder CERIOPORINA von Hagenow, 1851 
Family HETEROPORIDAE Waters, 1880 
Genus CERIOPORA Goldfuss, 1826 
TYPE SPECIES. Ceriopora micropora Goldfuss, 1826, by subse- 
quent designation of Gregory (1896); Upper Cretaceous, locality 
uncertain (see Nye 1976: 56). 
REMARKS. The genus Ceriopora is here interpreted to include 
cerioporids with a semi-erect, ‘massive’ colony-form. Colonies tend 
to be globular, dome or mound-shaped, pedunculate or columnar. 
They lack the bushy morphology seen in other cerioporid genera 
(e.g. Tetrocycloecia, Heteropora auctt.) in which colonies are con- 
structed of bifurcating cylindrical branches having a well-marked 
internal differentiation between endozone and exozone. 
Ceriopora rekohuensis sp. nov. Figs 18-25 
HOLOTYPE. IGNS BZ 204—1, from Pukekio, Chatham Island. 
PARATYPES. IGNS BZ 204-2 (thin sections plus remnants); NHM 
BZ 4777. 
NAME. From Rekohu (Misty Skies), the Moriori name for Chatham 
Island. 
DESCRIPTION. Colony small, the holotype measuring 8 mm in 
maximum width and the taller, sectioned paratype 10 mm high, 
pedunculate, a proximal stalk (broken-off in all available colonies) 
grading into an expanded head; head underside comprises exterior 
wall, upper surface covered by zooidal apertures of variable size, 
sometimes with larger autozooids distinct from smaller kenozooids 
but in other instances without obvious dimorphism in size; skeletal 
organization free-walled, apart from fixed-walled gonozooids. In 
thin section no clear distinction exists between endozone and 
exozone; budding apparently interzooecial in pattern; zooidal tubes 
long and gently curved in longitudinal section; walls variably mon- 
iliform, at least some of the constrictions marking positions of 
interzooidal pores, about 0.03—0.05 mm thick, not increasing appre- 
ciably in thickness from endozone to exozone; microstructure 
indistinctly laminated, cloudy, clotted in transverse sections of 
endozone; diaphragms present but extremely scarce; zooidal tubes 
disrupted by fouling organisms, including worm tubes, subsequently 
overgrown and embedded in colony structure. Autozooidal aper- 
tures subcircular, about 0.11—0.15 mm in diameter; kenozooidal 
apertures ovoidal, ranging down to 0.03 mm in diameter. Overgrown 
gonozooids visible in section (Fig. 25) and from one eroded example 
I] 
seen on surface of holotype; stellate in frontal outline, chamber 
extending as lobes between radial series of autozooidal apertures; 
floor formed of occluded, undifferentiated zooidal apertures; roof 
remnant probably comprising calcified exterior wall but microstruc- 
ture poorly-preserved and no obvious pseudopores visible; 
ooeciopore not observed. 
REMARKS. Mostaspects of the morphology of this new species are 
very similar to the type species of Ceriopora, C. micropora Goldfuss, 
as redescribed by Nye (1976). These include the gently curved 
zooidal tubes with variably moniliform walls, and the indistinct 
dimorphism in zooidal aperture size. However, wall thickness and 
aperture diameter is slightly greater in the Red Bluff Tuff species. 
Whereas only questionable gonozooids in thin section were observed 
by Nye (1976) in C. micropora, the stellate frontal outline of the 
gonozooid inC. rekohuensis resembles that seen in C. farringdonensis 
Gregory (see Pitt & Taylor 1990: fig. 117D), an Aptian species in 
which dimorphism of zooidal aperture sizes is totally lacking. 
Judging from Cuffey & Sorrentino’s (1985) redescription of three 
species of Ceriopora from the Pliocene of the eastern USA, all three 
species have zooids of distinctly larger diameter than C. rekohuensis. 
Genus TETROCYCLOECIA Canu, 1917 
TYPE SPECIES. Tetrocycloecia dichotoma Canu, 1917, =Ceriopora 
dichotoma Goldfuss, 1827, sensu Reuss 1848, by original designa- 
tion; Miocene, Eisenstadt, Austria (see Nye 1976: 147). 
?Tetrocycloecia sp. 
NHM BZ 4778-4780. 
Bo SW/eul 
MATERIAL. 
DESCRIPTION. Colony erect, with cylindrical, bifurcating branches, 
1.3—2.1 mm in diameter; skeletal organization free-walled; colony 
surface with autozooidal apertures surrounded and separated by 
smaller, more numerous kenozooidal apertures; interzooidal walls 
very thick at colony surface. Autozooids long and horn-shaped in 
branch longitudinal sections, budded within an axial endozone; 
apertures small, 0.07—0.09 mm in diameter, elongated parallel to 
growth direction. Kenozooids seemingly budded closer to colony 
surface; apertures subcircular, 0.02-0.05 mm wide, typically less 
than half the diameter of neighbouring autozooidal apertures. 
Gonozooid unknown. 
REMARKS. An etched, off-centred longitudinally ground surface 
provides the only indication of internal morphology in this species. 
In the absence of well-oriented thin sections, and of a gonozooid, 
this species can be no more than questionably assigned to 
Tetrocycloecia. Ranging from the Aptian to the Miocene (Pitt & 
Taylor 1990: 120), the relatively narrow branches of Tetrocycloecia, 
for example in 7: dichotoma and T. multiporosa, with kenozooidal 
apertures considerably outnumbering autozooidal apertures, are, 
however, characters also seen in the Red Bluff Tuff species. 
Suborder RECTANGULATA Waters, 1887a 
Family LICHENOPORIDAE Smitt, 1867 
Genus DISPORELLA Gray, 1848 
TYPE SPECIES. Discopora hispida Fleming, 1828, by original 
designation; Recent, Shetland Islands, U.K. 
Figs 26-29 
MATERIAL. IGNS BZ 205, asingle colony encrusting the stylasterid 
Sporadopora cf. marginata, Pukekio, Chatham Island. 
Disporella sp. 
