Quantitative evaluation reveals taxonomic over-splitting in extinct marine invertebrates: implications in conserving biodiversity

Abstract

Till date, morphology in general was characterized qualitatively to support the traditional classification system. This study for the first time uses an integrated approach to explore the appropriateness of traditional classification by superposing quantitative characters on qualitative classification using advanced mathematical techniques. Here, a quantitative method was applied that calculates changes in body shape by digitizing the inferred ecological niche and functional attributes of relevant morphological traits. Subsequently, absolute values were assigned to structural–functional traits of extinct atrypids to determine their taxonomy at a higher resolution. Investigating phenotypic diversity in these once abundant Paleozoic brachiopods from deep time is important for predicting future marine biodiversity of their closest living relatives and in conserving the marine ecosystem at large. Results show taxonomic over-splitting, a possible consequence of qualitative taxonomy. This study highlights the necessity of revisiting prior taxonomy by incorporating quantified traits and elicits the hazards of proposing classification based on qualitative traits alone. Perhaps, this study can be a starting point to improve the biological classification system in places where it must be based on morphology alone.