How to become a crab: Phenotypic constraints on a recurring body plan. (9th March 2021)

• Record Type: Journal Article
• Authors: Wolfe, Joanna M.; Luque, Javier; Bracken‐Grissom, Heather D.
• Is Part Of: BioEssays. Volume 43:Number 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-09
• Subjects: Anomura -- Brachyura -- carcinization -- convergent evolution -- Crustacea -- morphological integration -- phylogeny; Molecular biology -- Periodicals; Cytology -- Periodicals; Developmental biology -- Periodicals; 572.8
• DOI: 10.1002/bies.202100020
• Languages: English
• ISSNs: 0265-9247

Abstract

Abstract: A fundamental question in biology is whether phenotypes can be predicted by ecological or genomic rules. At least five cases of convergent evolution of the crab‐like body plan (with a wide and flattened shape, and a bent abdomen) are known in decapod crustaceans, and have, for over 140 years, been known as "carcinization." The repeated loss of this body plan has been identified as "decarcinization." In reviewing the field, we offer phylogenetic strategies to include poorly known groups, and direct evidence from fossils, that will resolve the history of crab evolution and the degree of phenotypic variation within crabs. Proposed ecological advantages of the crab body are summarized into a hypothesis of phenotypic integration suggesting correlated evolution of the carapace shape and abdomen. Our premise provides fertile ground for future studies of the genomic and developmental basis, and the predictability, of the crab‐like body form. Abstract : An example of convergent evolution, the king crab represents one of five instances where carcinization, the gain of a crab‐like body form, has occurred in crustaceans. We propose the flattened carapace and folded abdomen have coevolved by morphological integration, discuss possible adaptive significance, and suggest future developmental studies.