30
4
December
853
857
AGER, D. V. 1987. Why the rhynchonellid brachiopods survived and the spiriferids did not: a suggestion. Palaeontology, 30, 4, 853–857.
Derek V. Ager It is suggested that the rhynchonellid brachiopods survived to the present day whilst all other forms with spirolophous lophophores became extinct because the latter were restrained by calcareous spiralia whereas the former were able to extend their lophophores outside their shells. The Palaeontological Association (Free Access)