Evolutionary contingency in lingulid brachiopods across mass extinctions.

Morphology usually serves as an effective proxy for functional ecology, and evaluating morphological, anatomical, and ecological changes permits a deeper understanding of the nature of diversification and macroevolution. Lingulid (order Lingulida) brachiopods are both diverse and abundant during the early Palaeozoic but decrease in diversity over time, with only a few genera of linguloids and discinoids present in modern marine ecosystems, resulting in them frequently being referred to as "living fossils." The dynamics that drove this decline remain uncertain, and it has not been determined if there is an associated decline in morphological and ecological diversity.