Exceptionally preserved Mickwitzia from the Indian Springs Lagerstätte (Cambrian Stage 3), Nevada. (9th May 2016)

• Record Type: Journal Article
• Authors: Butler, Aodhán D.; Streng, Michael; Holmer, Lars E.; Babcock, Loren E.
• Is Part Of: Journal of paleontology. Volume 89:Number 6(2016)
• Page Start: 933
• Page End: 955
• Publication Date: 2016-05-09
• Subjects: Fossils -- Classification -- Periodicals; Paleontology -- Periodicals; Paléontologie -- Périodiques; Fossils -- Classification; Paleontology; Paleontologie; Periodicals; Electronic journals; 560.5
• DOI: 10.1017/jpa.2016.8
• Languages: English
• ISSNs: 0022-3360

Abstract

Abstract: Exceptionally preserved specimens of the Cambrian stem-group brachiopod Mickwitzia occidens Walcott, 1908 are described in detail from the Indian Springs Lagerstätte in Nevada, USA. Shell structure and preserved mantle setae from these specimens reveal a variable diagenetic (taphonomic) history and provide insight into the phylogenetic position of mickwitziids. Morphologic and morphometric comparison to M. monilifera (Linnarsson, 1869 ) from Sweden and M. muralensis Walcott, 1913 from British Columbia, Canada reveals clear species-level distinctions. Scanning electron microscopic analysis allows revision of the generic diagnosis. The Mickwitzia shell is characterized by the presence of inwardly pointing phosphatic cones and tangential setae-bearing tubes. The inwardly pointing cone structures are not consistent with setal bearing structures as previously thought, but rather represent endopunctae-like structures. Acrotretid-like shell structures and shell-penetrating setae in M. occidens strengthen the previously proposed close relationship between stem-group brachiopods and tommotiids, a group of small shelly fossils.