The limited value of traditional morphometric features in stromatoporoid taxonomy

Abstract

The morphological variation of stromatoporoids, which are solitary organisms, is partitioned into its presumably genetic and environmental components. Potentially heritable, environmentally mediated and residual components of morphological variability were estimated in a test set containing Devonian stromatoporoids of the genus Gerronostromaria from southern Poland using analysis of variance. The taxonomic importance of traditional morphometric features is limited, because they are dominated by the intra-skeletal component of variance. Conventional metrics were therefore replaced by stereological and textural quantities. Both stereological and textural features are dominated by the interskeletal and inter-locality components of variation and thus may be valuable in taxonomic and environmental studies of stromatoporoids. Statistical analyses of these characters (principal component analysis and cluster analysis) were performed. Of 13 characters considered most useful in taxonomic studies, only five have been used previously in conventional species definitions.

The stromatoporoidHabrostromain the upper Silurian (uppermost Pridoli)–Lower Devonian (Lochkovian) of North America, and the paleobiogeographic significance ofH.centrotum(Girty, 1895)

“…We have taken the position that the statistics we employed are useful and valid. Wolniewicz (2013, p. 954) agreed with us, stating, “The value of traditional features also increases when multivariate techniques are used, e.g. a canonical discriminant analysis.”…”

“…Wolniewicz (2010, 2013) took issue with some of the standard skeletal measurement and data interpretation employed by previous stromatoporoid workers. He was able to detect two species of Gerronostromaria from the Upper Devonian (Famennian) of Poland, using image analysis software.…”

“…He was able to detect two species of Gerronostromaria from the Upper Devonian (Famennian) of Poland, using image analysis software. Integral to the latter was the inclusion of stereological data (Wolniewicz, 2013). His techniques are fascinating, and show some potential for stromatoporoid identification.…”

“…Unfortunately, he is the only worker who has employed this technique, and did so on only one genus, the rectilinear Gerronostromaria . Wolniewicz acknowledged some shortcomings in his method: The skeleton must have a network of horizontal laminae and vertical pillars (Wolniewicz, 2010, p. 555), and the results he obtained are, “… valid for only the populations under study” (Wolniewicz, 2013, p. 955). We have taken the position that the statistics we employed are useful and valid.…”

Part E, Porifera (Revised), vol. 5, Complete Volume

“…The program's software allows rapid analysis of the measurements taken from photographs and is more objective than traditional measurements taken by an operator using a microscope. He has also written on the value of the usual measurements for stromatoporoid taxonomy (WolnieWiCz, 2013).…”