Cnidom in Ceriantharia (Cnidaria, Anthozoa): new findings in the composition and micrometric variations of cnidocysts

GARESE, A.; CORREA, FABIOLA; ACUÑA, F. H.; STAMPAR, S.

PeerJ

Peerj Publishing

Año: 2023

2167-8359

Background: Like all cnidarians, the subclass Ceriantharia (Cnidaria, Anthozoa) isknown for producing cnidocysts, which mainly serve for prey immobilization,predator defense, and locomotion.Aim: The present study aimed to understand the variability of the cnidom, i.e., theinventory of all cnidocyst types, in the ceriantharians (or tube anemones)Ceriantheomorphe brasiliensis (10 individuals) and Cerianthus sp. (sevenindividuals).Methods: In each individual, 30 intact cnidocysts of each identified type weremeasured in the following parts of tube anemones: marginal tentacles (four fromeach individual), labial tentacles (four from each individual), column, actinopharynxand metamesenteries. Each of these structures was divided into three levels (high,middle, and low) and the cnidom was analyzed. Statistical descriptive parameters(mean, standard deviation, minimum and maximum) of the sizes of all types ofcnidocysts were calculated. The normality of the data for cnidocyst length wasassessed using a Shapiro-Wilk test (a = 0.05). Based on the acceptance or rejection ofthe normality, either linear models or generalized linear models were used to evaluatevariations in cnidocyst lengths. The normality of the cnidocyst length was tested byShapiro-Wilk, and due to its rejection, generalized linear mixed models were appliedto test the cnidocyst lengths variations.Results: The analysis of Ceriantheomorphe brasiliensis revealed 23 categories ofcnidocysts, thereby expanding the understanding of its cnidome. The cnidoms ofCeriantheomorphe brasiliensis and Cerianthus sp. presented intraspecific variations,both qualitatively and in the lengths of cnidocysts. The cnidoms of the two speciesstudied also showed qualitative intra-individual variations between different levels(high, middle, low) within each structure of the tube anemone (tentacles,actinopharynx, column and metamesenteries). Some cnidocyst types, such as atrichsfrom the column of C. brasiliensis, presented a length gradient along the column,from larger lengths at the “low” level to smaller lengths at the “high” level.[Q1][Q2]How to cite this article Garese A, Goes Correa F, Acuña FH, Stampar SN. 2023. Cnidom in Ceriantharia (Cnidaria, Anthozoa): newfindings in the composition and micrometric variations of cnidocysts. PeerJ 11:e15549 DOI 10.7717/peerj.15549These cannot be changed: The order of authors Co-first and correspondingauthorships The order of the affiliations.Please only ANNOTATE theproof. Do not edit the PDF. Ifmultiple authors will review thisPDF, please return one filecontaining all corrections.Submitted 17 January 2023Accepted 23 May 2023Published TBDCorresponding authorAgustín Garese,agustingarese@gmail.comAcademic editorAlexander EreskovskyAdditional Information andDeclarations can be found onpage 19DOI 10.7717/peerj.15549Copyright2023 Garese et al.Distributed underCreative Commons CC-BY 4.0Conclusions: The cnidom of a tube anemone could be better described if samples aretaken at different levels of the structures, as observed in C. brasiliensis. Besides, wecan conclude that the cnidocyst lengths of both C. brasiliensis and Cerianthus sp.present intraspecific variation, which is coincident with that observed in actiniariansea anemones. Moreover, as main conclusion, this work also proved that individualsof tube anemone species could present qualitative intra-structure variations in boththe cnidom and cnidocyst lengths. This characteristic appears as an exception incnidom variations, and has so far not been recorded even in the most studiedactiniarian sea anemones. Finally, the intra-structure cnidocyst variations couldreveal different functions of the different levels of a particular body part of theorganisms.