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A new view of insect-crustacean relationships I. Inferences from neural cladistics and comparative neuroanatomy.
Arthropod Struct Dev. 2011 May; 40(3):276-88.AS

Abstract

Traditional hypotheses regarding the relationships of the major arthropod lineages focus on suites of comparable characters, often those that address features of the exoskeleton. However, because of the enormous morphological variety among arthropods, external characters may lead to ambiguities of interpretation and definition, particularly when species have undergone evolutionary simplification and reversal. Here we present the results of a cladistic analysis using morphological characters associated with brains and central nervous systems, based on the evidence that cerebral organization is generally robust over geological time. Well-resolved, strongly supported phylogenies were obtained from a neuromorphological character set representing a variety of discrete neuroanatomical traits. Phylogenetic hypotheses from this analysis support many accepted relationships, including monophyletic Chelicerata, Myriapoda, and Hexapoda, paraphyletic Crustacea and the union of Hexapoda and Crustacea (Tetraconata). They also support Mandibulata (Myriapoda + Tetraconata). One problematic result, which can be explained by symplesiomorphies that are likely to have evolved in deep time, is the inability to resolve Onychophora as a taxon distinct from Arthropoda. Crucially, neuronal cladistics supports the heterodox conclusion that both Hexapoda and Malacostraca are derived from a common ancestor that possessed a suite of discrete neural centers comprising an elaborate brain. Remipedes and copepods, both resolved as basal to Branchiopoda share a neural ground pattern with Malacostraca. These findings distinguish Hexapoda (Insecta) from Branchiopoda, which is the sister group of the clade Malacostraca + Hexapoda. The present study resolves branchiopod crustaceans as descendents of an ancestor with a complex brain, which means that they have evolved secondary simplification and the loss or reduction of numerous neural systems.

Authors+Show Affiliations

Department of Neuroscience, University of Arizona, 1040 E. 4th St., Gould-Simpson Bldg. #611, Tucson, AZ 85721, USA. flybrain@neurobio.arizona.eduNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21333750

Citation

Strausfeld, Nicholas J., and David R. Andrew. "A New View of Insect-crustacean Relationships I. Inferences From Neural Cladistics and Comparative Neuroanatomy." Arthropod Structure & Development, vol. 40, no. 3, 2011, pp. 276-88.
Strausfeld NJ, Andrew DR. A new view of insect-crustacean relationships I. Inferences from neural cladistics and comparative neuroanatomy. Arthropod Struct Dev. 2011;40(3):276-88.
Strausfeld, N. J., & Andrew, D. R. (2011). A new view of insect-crustacean relationships I. Inferences from neural cladistics and comparative neuroanatomy. Arthropod Structure & Development, 40(3), 276-88. https://doi.org/10.1016/j.asd.2011.02.002
Strausfeld NJ, Andrew DR. A New View of Insect-crustacean Relationships I. Inferences From Neural Cladistics and Comparative Neuroanatomy. Arthropod Struct Dev. 2011;40(3):276-88. PubMed PMID: 21333750.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A new view of insect-crustacean relationships I. Inferences from neural cladistics and comparative neuroanatomy. AU - Strausfeld,Nicholas J, AU - Andrew,David R, Y1 - 2011/02/17/ PY - 2010/09/03/received PY - 2011/01/28/revised PY - 2011/02/08/accepted PY - 2011/2/22/entrez PY - 2011/2/22/pubmed PY - 2011/10/19/medline SP - 276 EP - 88 JF - Arthropod structure & development JO - Arthropod Struct Dev VL - 40 IS - 3 N2 - Traditional hypotheses regarding the relationships of the major arthropod lineages focus on suites of comparable characters, often those that address features of the exoskeleton. However, because of the enormous morphological variety among arthropods, external characters may lead to ambiguities of interpretation and definition, particularly when species have undergone evolutionary simplification and reversal. Here we present the results of a cladistic analysis using morphological characters associated with brains and central nervous systems, based on the evidence that cerebral organization is generally robust over geological time. Well-resolved, strongly supported phylogenies were obtained from a neuromorphological character set representing a variety of discrete neuroanatomical traits. Phylogenetic hypotheses from this analysis support many accepted relationships, including monophyletic Chelicerata, Myriapoda, and Hexapoda, paraphyletic Crustacea and the union of Hexapoda and Crustacea (Tetraconata). They also support Mandibulata (Myriapoda + Tetraconata). One problematic result, which can be explained by symplesiomorphies that are likely to have evolved in deep time, is the inability to resolve Onychophora as a taxon distinct from Arthropoda. Crucially, neuronal cladistics supports the heterodox conclusion that both Hexapoda and Malacostraca are derived from a common ancestor that possessed a suite of discrete neural centers comprising an elaborate brain. Remipedes and copepods, both resolved as basal to Branchiopoda share a neural ground pattern with Malacostraca. These findings distinguish Hexapoda (Insecta) from Branchiopoda, which is the sister group of the clade Malacostraca + Hexapoda. The present study resolves branchiopod crustaceans as descendents of an ancestor with a complex brain, which means that they have evolved secondary simplification and the loss or reduction of numerous neural systems. SN - 1873-5495 UR - https://www.unboundmedicine.com/medline/citation/21333750/A_new_view_of_insect_crustacean_relationships_I__Inferences_from_neural_cladistics_and_comparative_neuroanatomy_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1467-8039(11)00009-0 DB - PRIME DP - Unbound Medicine ER -