Acontia and mesentery nematocysts of the sea anemone &lt;i&gt;Metridium senile&lt;/i&gt; (Linnaeus, 1761) (Cnidaria: Anthozoa)

The cnidome of the scleractinian cold‐water coral Lophelia pertusa (Linnaeus, 1758, syn. Lophohelia prolifera) was described by Carlgren in 1940. Due to a renewed interest in the cnidae of L. pertusa, specifically comparisons of adult and larval cnidae and their functions, we now redescribe the cnidome from material collected at the Tisler reef in Norway, close to Carlgren's collection site at Saekken (Sweden). Cnidae from column, tentacles, actinopharynx, mesenterial filaments and acontia were investigated. Fresh tissue preparations were compared to histological preparations of decalcified polyps to verify the presence of cnidocysts and secretory cells, and their composition and organization within tissues. The cnidome included microbasic b‐mastigophores, microbasic and mesobasic p‐mastigophores, holotrichous isorhizas and spirocysts. The nematocyst type cnidae (b‐, p‐mastigophores, isorhizas) appeared in different size classes with different distributions within the tissue. Spirocysts were highly variable in shape and size, without distinct size classes. In addition, developing stages of cnidae were documented, with new observations on the succession of p‐mastigophore shaft development. The present observations were in general congruent with the cnidocyst descriptions from L. prolifera made by Carlgren; however, a tiny cnida, possibly of isorhiza type, has been added. Finally, the use of the term acontia is discussed.

show abstract

“…A), as previously noted in the sea anemones Metridium senile and Sagartiogeton viduatus (Östman et al . ,b, ).…”

Section: Discussionmentioning

confidence: 97%

“…Documentation of the morphology of developing cnidae (cnidoblasts) in different stages of maturation has been carried out for the anthozoans Metridium senile and Sagartiogeton viduatus by Östman et al . (,b, ). Möbius () suggested that cnidoblasts differentiate beneath the mature cnidocytes (commented in Robson ).…”

Section: Introductionmentioning

confidence: 97%

The cnidome and internal morphology of Lophelia pertusa (Linnaeus, 1758) (Cnidaria, Anthozoa)

Strömberg

Östman

2016

Acta Zoologica

Self Cite

View full text Add to dashboard Cite

show abstract

“…The present work, as well as our previous cnidae studies of Metridium senile (Östman et al . , b, c), is crucial for our ongoing investigations on nematocyst incorporations in the nudibranchs A. glauca and Aolidia papillosa (Linnaeus, 1761) (C. Östman, F. Gustavsson, A. Karlsson, C. Roat, in preparation). To gain an insight, if these nudibranchs have a preference for storing‐specific cnidae (see Conklin and Mariscal ; Day and Harris ; Frick , ) and if immature nematocysts are incorporated into their cnidosacs (see Greenwood and Mariscal ; Martin and Walther ), we first performed a similar detailed study of the cnidocysts of S. viduatus as we did with M. senile (Östman et al .…”

Section: Introductionmentioning

confidence: 99%

“…To gain an insight, if these nudibranchs have a preference for storing‐specific cnidae (see Conklin and Mariscal ; Day and Harris ; Frick , ) and if immature nematocysts are incorporated into their cnidosacs (see Greenwood and Mariscal ; Martin and Walther ), we first performed a similar detailed study of the cnidocysts of S. viduatus as we did with M. senile (Östman et al . , b, c).…”

Section: Introductionmentioning

confidence: 99%

“…Carlgren () reported four cnidae types of S. viduatus (as Actinothoe viduata , Muller) from the Gullmarsfjord, namely basitrichs (= b‐mastigophores), microbasic amastigophores (= p‐amastigophores) (see Östman et al . ), microbasic p‐mastigophores and spirocysts. Carlgren gave the size range of these nematocysts from different parts of the anemone.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cnidae in the sea anemone Sagartiogeton viduatus (Muller, 1776) (Cnidaria, Anthozoa); A comparison to cnidae in the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria, Anthozoa)

Östman

Borg²,

Roat

et al. 2012

Acta Zoologica

Self Cite

View full text Add to dashboard Cite

The cnidom of the sea anemone Sagartiogeton viduatus (Muller, 1776) is described from interference‐contrast light micrographs (LMs) and scanning electron micrographs (SEMs). Special attention is given to nematocyst maturation, including the differentiation of the shaft into proximal and main regions as helical folding of the shaft wall proceeds. Comparisons are made with Metridium senile (Linnaeus, 1761), whose cnidom, with a few exceptions, is closely similar to that of S. viduatus. The two anemones possess b‐ and p‐mastigophores, p‐amastigophores, isorhizas and spirocysts. Although the majority of cnidae in S. viduatus is smaller than corresponding ones in M. senile, they are grouped into the same size classes as those of M. senile, namely small, medium and large. The main differences from M. senile cnidae are the followings: (1) Large acontia p‐amastigophores are the largest nematocysts in S. viduatus. (2) They are noticeably larger than the large acontia b‐mastigophores, and (3) they are separated from the p‐amastigophores of M. senile by the sinusoid pattern of their U‐shaped capsular matrix. (4) The large acontia b‐mastigophores are microbasic and not mesobasic as in M. Senile, and (5) they do not produce darts. (6) Another difference from M. senile is the absence of catch‐tentacle isorhizas.

show abstract

New invasive predator reduces the abundance of native prey in a cold‐temperate marine fouling community

Battini

Giachetti

Castro

et al. 2021

Aquatic Conservation

View full text Add to dashboard Cite

Invasive species threaten the conservation of marine environments, and urgent management strategies are needed to prevent their introduction, establishment and spread. Specifically, marine invasive predators destabilize ecological interactions and alter community structure and function. However, most of the evidence showing the effect of these predators is restricted to a few species and regions, while for others the information remains scarce. This study experimentally evaluated the ecological effects of the sea slug Pleurobranchaea maculata, a recently introduced invasive predator, on the fouling communities of a cold‐temperate port in the South‐western Atlantic. The results show that increasing predation pressure reduces significantly the abundance of sea anemones, which are among the preferred prey items. This study reveals new evidence to help better understand the effects of P. maculata on the biological communities of a recently invaded region. Furthermore, it provides the first experimental evidence supporting the hypothesis that marine invasive predators can induce a significant decrease in the abundance of native species in benthic communities of cold‐temperate marine environments in the South‐western Atlantic.

show abstract

Acontia and mesentery nematocysts of the sea anemone <i>Metridium senile</i> (Linnaeus, 1761) (Cnidaria: Anthozoa)

Cited by 29 publications

References 27 publications

The cnidome and internal morphology of Lophelia pertusa (Linnaeus, 1758) (Cnidaria, Anthozoa)

The cnidome and internal morphology of Lophelia pertusa (Linnaeus, 1758) (Cnidaria, Anthozoa)

Cnidae in the sea anemone Sagartiogeton viduatus (Muller, 1776) (Cnidaria, Anthozoa); A comparison to cnidae in the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria, Anthozoa)

New invasive predator reduces the abundance of native prey in a cold‐temperate marine fouling community

Contact Info

Product

Resources

About