Early Cambrian "soft-shelled" brachiopods as possible stem-group phoronids
2009 (English)In: Acta Palaeontologica Polonica, ISSN 0567-7920, Vol. 54, no 2, 307-314 p.Article in journal (Refereed) Published
Brachiopods and phoronids are widely recognised as closely related lophophorate phyla. but the lack of morphological intermediates linking the bivalved bodyplan of brachiopods with tubular phoronids has frustrated precise phylogenetic placement. Here we describe Lingulosacculus nuda gen. et sp. nov., a new "soft-shelled" brachiopod from the Early Cambrian Mural Formation of western Alberta which provides a plausible candidate for a phoronid stem-group within (paraphyletic) Brachiopoda. In addition to its non-biomineralised shell, L. nuda had a ventral valve with an exceptionally long, pocket-like extension (pseudointerarea) that Would have allowed the transformation of criss-crossing brachiopod-type musculature to the longitudinal arrangement typical of phoronids. "Soft-shelled" linguliform brachiopods have previously been reported from both the Chengjiang and Burgess Shale Lagerstatten which, together with L. nuda. probably represent two independent losses of shell mineralisation in brachiopods.
Place, publisher, year, edition, pages
2009. Vol. 54, no 2, 307-314 p.
Lophophorata, Lophotrochozoa, Brachiopoda, Phoronida, exceptional preservation, problematica
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:uu:diva-128404ISI: 000267673300010OAI: oai:DiVA.org:uu-128404DiVA: diva2:331535