Surveying keratose sponges (Porifera, demospongiae, Dictyoceratida) reveals hidden diversity of host specialist barnacles (Crustacea, Cirripedia, Balanidae)

Andrew M Hosie; Jane Fromont; Kylie Munyard; Nerida G Wilson; Diana S Jones

doi:10.1016/j.ympev.2021.107179

Surveying keratose sponges (Porifera, demospongiae, Dictyoceratida) reveals hidden diversity of host specialist barnacles (Crustacea, Cirripedia, Balanidae)

Mol Phylogenet Evol. 2021 Aug:161:107179. doi: 10.1016/j.ympev.2021.107179. Epub 2021 Apr 20.

Authors

Andrew M Hosie¹, Jane Fromont², Kylie Munyard³, Nerida G Wilson⁴, Diana S Jones²

Affiliations

¹ Collections & Research, Western Australian Museum, 49 Kew St, Welshpool 6106 WA, Australia; Curtin Medical School, Curtin University, Bentley 6102 WA, Australia. Electronic address: andrew.hosie@museum.wa.gov.au.
² Collections & Research, Western Australian Museum, 49 Kew St, Welshpool 6106 WA, Australia.
³ Curtin Medical School, Curtin University, Bentley 6102 WA, Australia.
⁴ Collections & Research, Western Australian Museum, 49 Kew St, Welshpool 6106 WA, Australia; School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley 6009 WA, Australia.

PMID: 33887480
DOI: 10.1016/j.ympev.2021.107179

Abstract

Sponges represent one of the most species-rich hosts for commensal barnacles yet host utilisation and diversity have not been thoroughly examined. This study investigated the diversity and phylogenetic relationships of sponge-inhabiting barnacles within a single, targeted host group, primarily from Western Australian waters. Specimens of the sponge order Dictyoceratida were surveyed and a total of 64 host morphospecies, representing four families, were identified as barnacle hosts during the study. Utilising molecular (COI, 12S) and morphological methods 42 molecular operational taxonomic units (MOTUs) of barnacles, representing Acasta, Archiacasta, Euacasta and Neoacasta were identified. Comparing inter- and intra-MOTU genetic distances showed a barcode gap between 2.5% and 5% for COI, but between 1% and 1.5% in the 12S dataset, thus demonstrating COI as a more reliable barcoding region. These sponge-inhabiting barnacles were demonstrated to show high levels of host specificity with the majority being found in a single sponge species (74%), a single genus (83%) or a single host family (93%). Phylogenetic relationships among the barnacles were reconstructed using mitochondrial (12S, COI) and nuclear (H3, 28S) markers. None of the barnacle genera were recovered as monophyletic. Euacasta was paraphyletic in relation to the remaining Acastinae genera, which were polyphyletic. Six well-supported clades of molecular operational taxonomic units, herein considered to represent species complexes, were recovered, but relationships between them were not well supported. These complexes showed differing patterns of host usage, though most were phylogenetically conserved with sister lineages typically occupying related hosts within the same genus or family of sponge. The results show that host specialists are predominant, and the dynamics of host usage have played a significant role in the evolutionary history of the Acastinae.

Keywords: Acastinae; Co-speciation; Phylogenetics; Radiation; Specialisation; Speciation; Symbiosis.

Publication types

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

MeSH terms

Animals
Host Specificity*
Phylogeny*
Porifera*
Thoracica / classification*
Western Australia