Page 294 - Introduction to Paleobiology and The Fossil Record

THE BASAL METAZOANS: SPONGES AND CORALS 281

Silurian Goniophyllum was pyramidal with a
60 deep calyx, whereas the Devonian Calceola
was a slipper-shaped form with a semicircular
lid and the compound Phillipsastrea had a
50 massive, astraeoid growth mode (Fig.
Cerioid
11.25).
Diverse rugosan faunas occurred during
40 the Carboniferous Period. Solitary forms such
Number of genera 30 Coenostoid Caninia, the cylindrical Dibunophyllum with
as the large horn-shaped to cylindrical
a marked dissepimentarium, the long cylindri-
Phaceloid
Zaphrentis are often conspicuous members of
Meandroid cal Palaeosmilia, and the smaller horn-shaped
20 Carboniferous coral assemblages. The fascic-
ulate, phaceloid Lonsdaleia and Lithostrotion
Cerioid
with usually massive, cerioid growth modes
10 are locally common. The order declined during
Astraeoid
Aphroid the Permian until there were only 10 families
left, and these disappeared by the end-Permian
0 mass extinction (see p. 170).
Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Tertiary Tabulate corals

As the name suggests, tabulate corals have
well-developed tabulae (Fig. 11.26). The septa
Figure 11.21 Schematic graph of the distribution are usually very much reduced to short spines
of colonial growth modes through the or are absent, and dissepiments are variably
Phanerozoic. (Based on data in Coates, A.G. & developed (Fig. 11.27). The group is varied,
Oliver, W.A. Jr. 1973. In Animal Colonies: with erect, massive, sheet-like and chain-like
Development and function through time. colonies and branching forms; some authors
Dowden, Hutchinson and Ross.)
have suggested that some tabulates, such as

perimeter M, × 5
50%
columnar
height
width
M

+
bulbous

branching

width, × 3 (perimeter + height) × 2
50%

tabular domal
Figure 11.22 Ternary plot of colonial growth modes based on the shape of the colonial coral. (Based
on data in Scrutton, C.T. 1993. Cour. Forsch. Inst. Senckenberg 164.)