A QUANTITATIVE APPROACH TO ASSESSING CORAL SEPTAL DENTITION

Certain aspects of coral morphology are highly plastic, causing challenges within coral systematics. Micro-scale features of the coral skeleton, which include characteristics of septal teeth, may be more taxonomically reliable than larger-scale coral skeletal features, such as colony shape. Septal tooth shape in the family Mussidae (Scleractinia) is an important diagnostic feature, but tooth shape can be difficult to convey in morphological descriptions. Species descriptions frequently use ambiguous qualitative terms like “triangular” and “lobed” to describe septal dentition. The aim of this analysis is to assess whether mussid coral species can be quantitatively distinguished from one another using an elliptic Fourier analysis of septal teeth.

Septal tooth profiles were acquired by outlining the curve between adjacent tooth apexes. This curve was then reflected to create an ovoid shape appropriate for an outline analysis, and the resulting shapes were analyzed using an elliptic Fourier analysis.

The results suggest that tooth shape among mussid coral species varies reliably in several different dimensions, revealing that there is quantifiable inter-specific variation in septal tooth shape. This analysis indicates that certain micro-features vary more among species than they do within them, corroborating observations that micro-features are taxonomically meaningful. This analysis demonstrates a novel approach to exploring coral micro-features.