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Updated: Jul 9, 2026
07:47
The Barnacle Balanus improvisus as a Marine Model - Culturing and Gene Expression
Published on: August 8, 2018
The tempo and mode of barnacle evolution
Marcos Pérez-Losada1, Margaret Harp, Jens T Høeg
1Department of Biology, Brigham Young University, Provo, UT 84602-5181, USA. mp323@byu.edu
Molecular Phylogenetics and Evolution
|November 23, 2007
Summary
This study redefines barnacle evolution using extensive DNA and morphological data. It reveals that shell-less barnacles evolved multiple times, challenging previous assumptions about their evolutionary history and classification.
Area of Science:
- * Evolutionary Biology
- * Phylogenetics
- * Marine Biology
Background:
- * Previous barnacle evolutionary studies were limited by small sample sizes.
- * Understanding thoracican barnacle relationships requires comprehensive data.
Purpose of the Study:
- * To resolve barnacle evolutionary relationships using combined molecular and morphological data.
- * To investigate the tempo and mode of barnacle evolution.
- * To reassess existing hypotheses on thoracican barnacle character evolution.
Main Methods:
- * Combined DNA sequences from three nuclear genes (18S, 28S, H3) and 44 morphological characters.
- * Analyzed 76 thoracican and 15 rhizocephalan species.
- * Employed maximum parsimony, maximum likelihood, and Bayesian inference with 14 fossil calibrations.
Main Results:
- * Identified Iblomorpha as monophyletic.
- * Demonstrated that shell-less pedunculated barnacles (Heteralepadomorpha) evolved at least twice from plated ancestors.
- * Found that asymmetry and peduncle loss occurred twice, invalidating current Verrucomorpha and Sessilia classifications.
- * Established monophyly for Verrucidae and Balanomorpha, forming a clade.
- * Revealed Scalpellomorpha are not monophyletic.
- * Dated Thoracica suborder evolution to the Early Carboniferous (340 mya) and Sessilia radiation to the Upper Jurassic (147 mya).
Conclusions:
- * Current hypotheses on Cirripedia Thoracica character evolution are largely rejected.
- * The study necessitates a significant reclassification of thoracican barnacles based on new phylogenetic insights.
- * Asymmetry and peduncle loss represent convergent evolutionary events within Thoracica.
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