Ceriantheomorphe brasiliensis (Cnidaria; Ceriantharia): how does it behave?

ABSTRACT

Behaviour research on Cnidaria, particularly Ceriantharia (Cnidaria, Anthozoa), is generally uncommon. Although ceriantharians or tube-dwelling anemones are known to build soft tubes, their tube-building behaviours remain unknown. In this study, we describe for the first time the tube-building behaviour of Ceriantheomorphe brasiliensis and detail its behaviour in natural habitat, including illustrations and videos of live specimens. Our results showed that C. brasiliensis can build more than one tube throughout its life, the tubes are usually ‘L-shaped’, longer than the polyp, and vertically oriented when built in deeper substrates, but horizontally oriented when built in shallower substrates. During tube construction, the polyp does not feed or use its tentacles to catch or select specific sediment particle sizes for tube construction. Given the vertical orientation of the tube, it is possible that the tube-building behaviour of C. brasiliensis differs from that of other species. Although this study only included a single specimen, the behaviours observed were constantly repeated by the animal in every test, from the first trial to the last, suggesting that they can occur on occasion. Furthermore, this research contains useful information that may guide future studies of tube-building behaviour in Ceriantharia which are, currently, non-existent.

KEYWORDS:

• Anthozoa
• behaviour
• bioconstruction
• tube-dwelling anemone
• tube-building

Acknowledgements

We are highly indebted to Brigitte and the maintenance workers at UNESP-Assis for their assistance with experiments, as well as Ursina Enz, Celine S.S. Lopes and Gabriel G. da Costa. We are also thankful to Marcelo V. Kitahara for helping with SCUBA dive and filming in situ, Rogerio Caetano da Costa for crab identification and Sergio R. Floeter for fishes identification. A special thanks to Kleber Del-Claro for insightful comments that greatly improved this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Compliance with ethical standards

Ethical approval

All applicable international, national, and/or institutional guidelines for animal testing, animal care and use of animals were followed by the authors.

Sampling and field studies

All necessary permits for sampling and observational field studies have been obtained by the authors from the competent authorities and are mentioned in the acknowledgements, if applicable.

Data availability

All data generated or analysed during this study are included in this published article and its supplementary information files.

Author contribution

HC and SNS sampled and identified the ceriantharian specimen in this study. HC wrote the first draft of the manuscript to which SNS added significant improvements. All authors read and approved the final manuscript.

Additional information

Funding

HC was financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 88887.301759/2018-00, and by the Conselho Nacional de Desenvolvimento Científico e Tecnológico – Brasil (CNPq) – Finance Code 141329/2020-3. SNS was supported by São Paulo Research Foundation (FAPESP), grant numbers 2015/24408-4, 2016/50389-0, 2019/03552-0, CNPq (PROTAX), grant number 440539/2015-3, and CNPq (Research Productivity Scholarship) grant number 301293/2019-8.