Preprint Hypothesis Version 1 Preserved in Portico This version is not peer-reviewed

How to Become a Crab: Phenotypic Constraints on a Recurring Body Plan

Version 1 : Received: 24 December 2020 / Approved: 25 December 2020 / Online: 25 December 2020 (13:31:09 CET)
Version 2 : Received: 1 March 2021 / Approved: 2 March 2021 / Online: 2 March 2021 (12:43:52 CET)

A peer-reviewed article of this Preprint also exists.

Journal reference: BioEssays 2021
DOI: 10.1002/bies.202100020


A fundamental question in biology is whether phenotypes can be predicted by ecological or genomic rules. For over 140 years, convergent evolution of the crab-like body plan (with a wide and flattened shape, and a bent abdomen) at least five times in decapod crustaceans has been known as ‘carcinization’. The repeated loss of this body plan has been identified as ‘decarcinization’. We offer phylogenetic strategies to include poorly known groups, and direct evidence from fossils, that will resolve the pattern 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.


Crustacea; Anomura; Brachyura; Carcinization; Phylogeny; Convergent evolution; Morphological integration


BIOLOGY, Anatomy & Morphology

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0

Notify me about updates to this article or when a peer-reviewed version is published.

We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.