Multiple evolutionary transitions of reproductive strategies in a phylum of aquatic colonial invertebrates

Heather E. Grant, Andrew N. Ostrovsky, Helen Louise Jenkins, Leandro Manzoni Vieira, Dennis P. Gordon, Peter G. Foster, Olga N. Kotenko, Abigail M. Smith, Björn Berning, Joanne Porter, Javier Souto-Derungs, Wayne K. Florence, Kevin Tilbrook, Andrea Waeschenbach

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Parental care is considered crucial for the enhanced survival of offspring and evolutionary success of many metazoan groups. Most bryozoans incubate their young in brood chambers or intracoelomically. Based on the drastic morphological differences in incubation chambers across members of the order Cheilostomatida (class Gymnolaemata), multiple origins of incubation were predicted in this group. This hypothesis was tested by constructing a molecular phylogeny based on mitogenome data and nuclear rRNA genes 18S and 28S with the most complete sampling of taxa with various incubation devices to date. Ancestral character estimation suggested that distinct types of brood chambers evolved at least 10 times in Cheilostomatida. In Eucratea loricata and Aetea spp. brooding evolved unambiguously from a zygote-spawning ancestral state, as it probably did in Tendra zostericola, Neocheilostomata, and ‘Carbasea' indivisa. In two further instances, brooders with different incubation chamber types, skeletal and non-skeletal, formed clades (Scruparia spp., Leiosalpinx australis) and (Catenicula corbulifera (Steginoporella spp. (Labioporella spp., Thalamoporella californica))), each also probably evolved from a zygote-spawning ancestral state. The modular nature of bryozoans probably contributed to the evolution of such a diverse array of embryonic incubation chambers, which included complex constructions made of polymorphic heterozooids, and maternal zooidal invaginations and outgrowths.
Original languageEnglish
Article number20231458
JournalProceedings of the Royal Society B: Biological Sciences
Issue number2010
Early online date1 Nov 2023
Publication statusPublished - 8 Nov 2023


  • Bryozoa
  • brooding
  • endotrophy
  • larva
  • planktotrophy
  • viviparity

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • General Environmental Science
  • General Immunology and Microbiology
  • General Biochemistry,Genetics and Molecular Biology


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