13]C data from brachiopod shells and rugosan corallums
are rather concordant with the [[delta].
The present study deals with morphological variation at the corallum and intraspecific level, leaving aside details of ontogenetic variation.
The terminology and parameters of the corallum shape and size follow those of Young & Scrutton (1991) and Young & Elias (1995), and the measurement methods are largely based on the technique applied by Young & Elias (1995).
The bulbous shape is less common and only one corallum is columnar (Table 1).
curvata) que se detectan facilmente aunque solo en ciertas partes del corallum.
Diagnosis: El corallum presenta crecimientos incrustantes y submasivos.
All the colonies examined showed an irregular helicospiral pattern of growth, with the parameters of each turn (pitch and diameter) changing from the base to the apex of the corallum (Fig.
This is mainly due to the paucity of held studies that have focused on this group; in particular, very few data are available concerning the corallum shape, the growth pattern, and the growth rate of the colonies.
For three coralla additionally a series of peels was analysed, made at a distance of 1 cm from the axial part and side parts of the corallum.
The terminology of bulbous corallum shapes follows Young & Scrutton (1991) and Young & Elias (1995).
Although skeletons of dead corals are bored by a variety of endolithic microorganisms, there has been no evidence that endoliths can penetrate the layer of tissue that covers living coral surfaces, leading to the conclusion that infestation by a limited number of specialized endoliths occurs early in the life of a coral, and that endolithic algae and fungi continue to grow in parallel with the accretion of the corallum (8).
eydouxi in petrographic thin sections revealed the presence of algal and fungal endoliths, as well as the presence of cone-like protrusions on the surface of the corallum in both species.