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Neuroanatomy in a middle Cambrian mollisoniid and the ancestral nervous system organization of chelicerates.

ABSTRACT: Recent years have witnessed a steady increase in reports of fossilized nervous tissues among Cambrian total-group euarthropods, which allow reconstructing the early evolutionary history of these animals. Here, we describe the central nervous system of the stem-group chelicerate Mollisonia symmetrica from the mid-Cambrian Burgess Shale. The fossilized neurological anatomy of M. symmetrica includes optic nerves connected to a pair of lateral eyes, a putative condensed cephalic synganglion, and a metameric ventral nerve cord. Each trunk tergite is associated with a condensed ganglion bearing lateral segmental nerves, and linked by longitudinal connectives. The nervous system is preserved as reflective carbonaceous films underneath the phosphatized digestive tract. Our results suggest that M. symmetrica illustrates the ancestral organization of stem-group Chelicerata before the evolution of the derived neuroanatomical characters observed in Cambrian megacheirans and extant representatives. Our findings reveal a conflict between the phylogenetic signals provided by neuroanatomical and appendicular data, which we interpret as evidence of mosaic evolution in the chelicerate stem-lineage.

SUBMITTER: Ortega-Hernandez J

PROVIDER: S-EPMC8776822 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature

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Neuroanatomy in a middle Cambrian mollisoniid and the ancestral nervous system organization of chelicerates.

Ortega-Hernández Javier J Lerosey-Aubril Rudy R Losso Sarah R SR Weaver James C JC

Nature communications 20220120 1

Recent years have witnessed a steady increase in reports of fossilized nervous tissues among Cambrian total-group euarthropods, which allow reconstructing the early evolutionary history of these animals. Here, we describe the central nervous system of the stem-group chelicerate Mollisonia symmetrica from the mid-Cambrian Burgess Shale. The fossilized neurological anatomy of M. symmetrica includes optic nerves connected to a pair of lateral eyes, a putative condensed cephalic synganglion, and a m ...[more]

PMID: 35058474

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Neuroanatomy in a middle Cambrian mollisoniid and the ancestral nervous system organization of chelicerates.

Publications

Neuroanatomy in a middle Cambrian mollisoniid and the ancestral nervous system organization of chelicerates.

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