Evolutionary trends in large pelagic filter-feeders

ABSTRACT

This paper attempts a synthesis of the evolution of large pelagic filter-feeding animals from the Cambrian to the present. Lineages known or suspected to have evolved large pelagic filter-feeding species are, in the order of their appearance, stem euarthropods, agnathan fishes, nautiloid cephalopods, placoderms, sharks, bony fishes, reptiles, ammonite cephalopods, and mammals. I discuss evolutionary trends which are apparent from the evolution of the large pelagic filter-feeding niche, which are 1. a size increase relative to their ancestral species, 2. the transition between taxonomic groups giving rise to pelagic filter-feeders, with vertebrates dominating the post-Cambrian, 3. the evolution of large pelagic filter-feeders from large carnivores in most, but not all cases, and 4. lengthy gaps in the record of pelagic filter-feeders around four of the big five mass extinctions.

KEYWORDS:

• Filter-feeder
• evolution
• radiodont
• nautiloid
• ammonite
• elasmobranch
• cetacean
• marine reptile
• bony fish

Acknowledgments

I thank Dr. Diego Rasskin-Gutman, Dr. Peter Van Roy and Ms. Lala Grace Calle’s for very valuable feedback on the manuscript and Ms. Glaiza Abril for editing it for language.

Disclosure statement

No potential conflict of interest was reported by the author.

Notes

1. The appendages are called tentacles in nautoloids and arms in derived cephalopods.