Abstract
Acricoactis brachyacontis sp. nov. is described based on specimens collected from Adak Island (Aleutian Islands, Alaska, USA). This acontiate sea anemone lacks a marginal sphincter, has only basitrichs in the acontia, and has six pairs of complete mesenteries, thus falling outside any existing family diagnosis. Nucleotide sequences from four gene regions (12S, 16S, 18S, COIII) corroborate the morphological finding, placing the sequenced individuals as sister to, rather than nested within, any existing monophyletic family. The new species therefore represents a new family, Acricoactinidae, as well as a new, monospecific genus. In spite of the lack of a marginal sphincter, individuals may fully retract and cover their tentacles through the contraction of the regular circular muscles in the distal region of the column. Various features of Acricoactinidae are shared with cuticulate species (e.g., with only one cycle of complete mesenteries, reduced acontia, and a few perfect mesenteries) and acuticulate species (e.g., with smooth, thin column, and a shallow water distribution), but molecular data presented here place the family within the clade Acuticulata.
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Acknowledgments
I thank the Aleut Corporation for permission to access the intertidal via tribal land. Funding for field work was provided by the American Museum of Natural History Lerner Gray Fund for Marine Research. The Willi Hennig Society is acknowledged for the free edition of TNT used in the phylogenetic analysis. Dr. Sarah Gerken (University of Alaska, Anchorage) and Mr. Raymond O’Neill assisted with logistics in Alaska. I thank Dr. Stephen Jewett (University of Alaska, Fairbanks) for corroborating sponge and tunicate identification via email. The comments of four anonymous reviewers greatly strengthened the manuscript. Molecular and morphological study was conducted using the laboratory resources of Dr. Marymegan Daly (Ohio State University).
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Communicated by B. W. Hoeksema
This article is registered in ZooBank under urn:lsid:zoobank.org :pub:E1390F2A-B4A9-40E3-B2ED-7EC2959F3EB0
Nomenclatural acts herein are registered as follows:
Family Acricoactinidae urn:lsid:zoobank.org:act:D68DDE9E-8092-47A7-8EBA-DF95D4036904
Genus Acricoactis urn:lsid:zoobank.org:act:06D0A0D6-D88B-4BD5-BE0E-B12CD91CD3D0
Species A. brachyacontis urn:lsid:zoobank.org:act:4CD1630F-ED7F-461A-8E93-B5BDFC975D6A
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Larson, P. Acricoactis brachyacontis sp. nov. from Adak Island, Alaska, represents a new genus and family of metridioidean sea anemone (Anthozoa: Hexacorallia: Actiniaria). Mar Biodiv 48, 1583–1590 (2018). https://doi.org/10.1007/s12526-016-0582-2
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DOI: https://doi.org/10.1007/s12526-016-0582-2