A Stem Group Brachiopod From The Lower Cambrian: Support For A Micrina (Halkieriid) Ancestry

2002/09/01 by Lars E. Holmer, Christian B. Skovsted, Alwyn Williams · 109 citations
Chemistry · Earth and Planetary Sciences · Materials Science · #Anatomy #Biology #Calcium Carbonate Crystallization and Inhibition #Chemistry #Genus #Geology #Group (periodic table) #Marine Biology and Ecology Research #Massif #Paleontology #Paleontology and Stratigraphy of Fossils #Seta #Shell (structure) #Zoology

paper · doi:10.1111/1475-4983.00265

published in Palaeontology 45(5), 875-882 (Wiley)

openalex publication_date 2002/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23

Abstract

The shell structure of the Lower Cambrian Mickwitzia , a bilaterally symmetrical bivalve hitherto doubtfully assigned to the Brachiopoda, confirms that the genus shares characters with linguliform brachiopods. The columnar lamination of its organophosphatic shell is homologous with that characterizing acrotretides. The shell, however, is also pervaded by striated apatitic tubes indistinguishable from those permeating the sclerites of the problematic organophosphatic, laminar–shelled Micrina which is close to Halkieria . No crown group brachiopods have such tubes that are presumed to have contained setae. The presence of both these features in the Mickwitzia shell suggests that the stock is a stem group brachiopod with a halkieriid ancestry.

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• The scleritome of Eccentrotheca from the Lower Cambrian of South Australia: Lophophorate affinities and implications for tommotiid phylogeny
• Early Cambrian “Soft-Shelled” Brachiopods as Possible Stem-Group Phoronids
• Darwin's dilemma: the realities of the Cambrian 'explosion'. [europepmc]
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• The earliest fossil record of the animals and its significance. [europepmc]
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• The scleritome of Paterimitra: an Early Cambrian stem group brachiopod from South Australia. [europepmc]
• Ediacaran skeletal metazoan interpreted as a lophophorate. [europepmc]
• Ecological innovations in the Cambrian and the origins of the crown group phyla. [europepmc]
• Gene Expression Patterns in Brachiopod Larvae Refute the "Brachiopod-Fold" Hypothesis. [europepmc]
• Orthrozanclus elongata n. sp. and the significance of sclerite-covered taxa for early trochozoan evolution. [europepmc]
• Hyoliths with pedicles illuminate the origin of the brachiopod body plan. [europepmc]
• Exceptionally preserved early Cambrian bilaterian developmental stages from Mongolia. [europepmc]
• Evolution and diversity of biomineralized columnar architecture in early Cambrian phosphatic-shelled brachiopods. [europepmc]
• Combining soft-bodied and three-dimensional fossils to reveal evolutionary modifications in early lingulellotretid brachiopods. [europepmc]

Related

• Shell structure, ontogeny and affinities of the Lower Cambrian bivalved problematic fossil Mickwitzia muralensis Walcott, 1913
• First record of a bivalved larval shell in Early Cambrian tommotiids and its phylogenetic significance
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• New data on molluscs and their shell microstructures from the Middle Cambrian Gowers Formation, Australia
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