| 
: 
~ CRETACEOUS-MIOCENE GENUS LICHENOPORA (BRYOZOA) 
| 
) Order CYCLOSTOMATIDA Busk, 1852 
Suborder RECTANGULINA Waters, 1887 
Family LICHENOPORIDAE Smitt, 1867 
Genus LICHENOPORA Defrance, 1823 
| TYPE SPECIES. Lichenopora turbinata Defrance, 1823, subse- 
| quently designated by d’Orbigny (1853: 963); Eocene (Lutetian), 
| France. 
_ DiAGNOsIs. Colony an even, acute cone, tapering basally, or with 
| the cone expanded outward laterally and supported by a short 
' peduncle; cone sides comprising a basal exterior wall with or 
_ without accessory kenozooidal prop-like processes. Zooids free- 
walled, tubular and straight in longitudinal section, opening on 
| subcircular frontal disc; both autozooids and kenozooids arranged 
 quincuncially near the edge of the disc, with older autozooids 
' tending to become grouped in several elevated radial series that 
' converge at or near the centre of the disc. Brood chamber located 
| centrally, but may have lobes extending into interradial areas be- 
| tween autozooidal rows; roof comprising an interior wall typically 
overgrown by the walls of shallow kenozooids that develop on its 
surface. Ooeciopore relatively large, situated near the centre of the 
disc. 
DISTRIBUTION. Cretaceous (Lower Cenomanian) — Eocene 
| (Lutetian) of Europe; Lower Miocene (Burdigalian) of New Zea- 
land. 
Lichenopora turbinata Defrance, 1823 Figs 1-10 
1823 Lichenopora turbinata Defrance: 257, pl. 46, figs 4, 4a. 
| 1852  Lichenopora turbinata Defrance; d’ Orbigny: 963. 
1909 Lichenopora turbinata Defrance; Canu: 138, pl. 17, figs 13— 
IS: 
Lichenopora turbinata Defrance; Bassler: 73, fig. 38,1. 
Lichenopora turbinata Defrance; Balavoine: 321. 
Lichenopora turbinata Defrance; Labracherie: 37, pl. 6, figs 
8-9. 
Lichenopora turbinata Defrance; Sabri: 141. 
| 1953 
| 1956 
1970 
ee 
) MATERIAL. MNHN,d’Orbigny Collection, B.50246 (a-f), Eocene, 
‘Parisien’, Orglandes, Manche, France; MNHN, Canu Collection, 
R. 53447, Eocene, M. Lutetian, Orglandes, Manche, France; BMNH 
| BZ 3163, Eocene, Hauteville, Manche, France, C. Lyell Collection, 
presented by T. R. Jones, 1896. 
The type material of this species is thought to be lost: none of the 
/MNHN specimens seem to represent that figured by Defrance. 
DESCRIPTION. Colony an inverted cone (Fig. 1), up to 4.7 mm high 
and 3.3 mm diameter, the cone diverging at an angle of about 45°. 
Apical end of cone evenly tapered and straight, or the apex some- 
what deflected at an angle from the axis; frequently broken, showing 
a dozen or so zooidal tubes in transverse section, each tube 0.09— 
0.13 mm diameter. Sides of cone formed of exterior wall (the 
upturned basal wall of the colony), more or less smooth textured; in 
\profile, the sides of the cone may be nearly straight or very gently 
jundulose; light concentric or subconcentric growth banding is typi- 
cal. Supportive kenozooidal props have not been observed, but some 
colonies bear grooves or planar areas down one side of the cone or 
‘transversely near the apex, representing bioimmurations of a sub- 
Stratum to which the cone was attached laterally (Fig. 6). Disc 
circular or elliptical (Figs 2-5) and slightly depressed beneath the 
level of the rim in well-preserved specimens. 
3 
Zooidal apertures near the outer (distal) margin of disc are 
arranged quincuncially (Fig. 7), have more or less equal diameter 
(0.14—-0.17 mm centre-to-centre spacing), and are polygonal in 
shape; there is no obvious distinction between autozooidal and 
kenozooidal apertures in these submarginal areas, but the outermost 
apertures beyond autozooidal rays are presumed to have been 
autozooids. In mature colonies with brood chambers, autozooids are 
arranged in elevated biserial rays with apertures alternating (Figs 3— 
5, 8), each aperture elliptical, up to 0.19 mm in diameter and 
elongated along the axis of the ray; there are up to 10 such rays, each 
with 4-6 pairs of autozooids, terminating abruptly near the concave 
centre of the disc. Between the rays are at least two rows of 
kenozooidal apertures. In immature colonies (i.e., smaller colonies 
without a visible brood chamber), the autozooidal rays are less 
distinct and shorter (Fig. 2), comprising 2-4 pairs of autozooids 
only, with some of the autozooids unpaired. 
The disc centre is composed of kenozooids which may become 
covered by a brood chamber with lobes extending between the 
autozooidal rays (Fig. 4). The roof of the brood chamber appears to 
be sparsely porous and is overgrown by a network of ridges that 
define shallow kenozooidal chambers (alveoli). The prominent 
ooeciostome (Fig. 9), located at or near the centre of the disc, 
comprises a short broad tube with an oval ooeciopore (Fig. 10), 
0.11—0.17 mm x 0.23 mm in diameter, roughly twice the width of an 
autozooidal aperture. 
REMARKS. Canu (1909) illustrated L. turbinata using several 
light micrographs, of which plate 17, fig. 14 was reproduced as a 
mirror-image line drawing in Bassler’s (1953: fig. 38.1) bryozoan 
Treatise. It is unfortunate that Bassler did not also illustrate L. 
turbinata in profile, for it has not generally been appreciated that 
the type species of Lichenopora is conical. According to Canu, the 
elongate conical form is rare, and shorter colonies are more com- 
monly found; however, the only colony he figured in profile is 
steeply conical. Similarly, the colony shown in profile by 
Labracherie (1970: pl. 6, fig. 9) is also a high cone, and all of the 
material available to us had the same form. Kenozooidal props 
have not been described in the literature and were not encountered 
in Our material. 
A few remarks on the ecology of L. turbinata are possible. 
Although Defrance (1823) illustrated a slight expansion at the 
apex of the cone and a flattened base, indicating a direct and 
limited attachment to a substratum, the groove-like or planar 
bioimmurations (Fig. 6) on the sides of a few colonies are evi- 
dence of a more extensive lateral attachment in some instances. 
Inasmuch as the molluscan fauna associated with L. turbinata at 
the localities where it is found in the Paris Basin is characteristic 
of seagrass beds (Jon Todd & Didier Merle, pers. comms, Decem- 
ber 1994), it is possible that colonies lived attached to seagrass. 
Associations between bryozoans and sea-grasses date back to the 
Maastrichtian (Voigt 1981), and are well-known from the Mediter- 
ranean at the present-day. For example, Hayward (1975) noted 
more than 30 bryozoan species, including one obligate epiphyte, 
living on Posidonia oceanica from Chios, Greece. However, none 
of these species have conical colonies like those of the Eocene L. 
turbinata, and fossil examples of seagrass associations from the 
Maastrichtian (Voigt 1981) and Eocene (Ivany et al. 1990) simi- 
larly lack conical colonies, although they do include 
lichenoporids. 
DISTRIBUTION. Eocene of France: Lutetian of the Paris Basin 
(Canu 1909), Middle-Upper Eocene of northern Aquitaine 
(Labracherie 1970). 
