The dawn of a dynasty: life strategies of Cambrian and Ordovician brachiopods

Abstract

Brachiopods are among the first animal phyla to emerge from the Cambrian Explosion, rapidly diversifying to all major palaeocontinental blocks within 20 million years. The group underwent another steep rise in diversity during the Ordovician, and their relative abundance and diversity made them one of the most successful invertebrate groups during the entire Palaeozoic. During this time, brachiopods lived in a range of environments and represented a significant component of marine ecosystems, yet information regarding their modes of life and ecology is somewhat limited. Recent studies, primarily from the Chengjiang and Burgess Shale Lagerstätten, have revealed that by the Middle Cambrian (Series 3, Stage 5) brachiopods from across the phylum had already developed a range of ecological strategies and life modes. Cambrian brachiopods occupied distinct trophic niches on soft and hard substrates and exhibited at least five types of lifestyles: pedicle attachment, pedicle anchoring, cemented, free‐lying and semi‐infaunal. Comparisons with Ordovician benthic assemblages show that despite the explosion of brachiopod taxa witnessed in the Ordovician, with the exception of the appearance of burrowing brachiopods, life strategies of brachiopods remained largely the same. Indicating that the majority of life modes observed in brachiopods had rapidly evolved and was already in place prior to the Great Ordovician Biodiversity Event.

Evolutionary significance of a middle Cambrian (Series 3) in situ occurrence of the pedunculate rhynchonelliform brachiopod Nisusia sulcata

“…, , ,; Topper et al . , , ; Holmer et al . ), but also from other types of exceptionally well‐preserved rhynchonelliform pedicle structures in lower Palaeozoic material (Bassett et al .…”

Brachiopods: origin and early history

“…In fact, most of the key life modes had been established prior to the Great Ordovician Biodiversification Event (Topper et al . in press). Challenges, however, exist in understanding the relationships between the individual groups near the base of the stem, particularly in clarifying the relationships between and within the tommotiids.…”

Early Palaeozoic diversifications and extinctions in the marine biosphere: a continuum of change

“…The fixed benthos is dominated by suspension-feeding organisms. The brachiopods dominated the Palaeozoic benthos, appearing in significant numbers during the Cambrian Explosion, and established a wide range of lifestyles supplemented during the GOBE (Topper et al 2018). Cambrian brachiopod faunas are generally of low diversity (Fig.…”

“…Nevertheless, the majority of brachiopod life modes had already been established by early Cambrian time with few additions later during the Ordovician Period (Topper et al 2018). The Early Ordovician diversifications around parts of tropical Gondwana (e.g.…”