Morphological and molecular diagnostic species characters of Staurozoa (Cnidaria) collected on the coast of Helgoland (German Bight, North Sea)

Abstract

Scientific knowledge and records on staurozoans are limited probably because of their inconspicuous life habit and the small number of specialists for this taxon. To increase the awareness for Staurozoa, we identified morphological and molecular features of the three staurozoan species Haliclystus tenuis Kishinouye, 1910, Haliclystus auricula Clark, 1863, and Craterolophus convolvulus (Johnston, 1835) collected on the coast of the island Helgoland to evaluate their suitability as diagnostic characters. Useful macromorphological diagnostic features were the patterns of white spots of nematocysts and internal arm structures, whereas tentacle and gonad follicle numbers showed high intraspecific variations. Morphometric measurements on photographs of living specimens provided reliable data for interspecific comparisons. Comprehensive nematocyst analyses revealed interspecific shape differences of isorhizas and three types of rhopaloids, indicating that the staurozoan cnidome is more diverse than previously assumed. However, the taxonomic value of nematocyst analyses in Staurozoa remains unclear because comprehensive data is still lacking for most species. Comparative molecular genetic sequence analyses of mitochondrial 16S and cytochrome c oxidase subunit I (COI) and nuclear 18S ribosomal DNA identified the three species and confirmed their morphological identification. In comparison to published data, our analyses indicate similarities between H. auricula and Haliclystus antarcticus Pfeffer, 1889. Proteomic fingerprinting by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) differentiated all three species, suggesting that this technique could provide an alternative rapid identification method for staurozoans.

Proteomic fingerprinting enables quantitative biodiversity assessments of species and ontogenetic stages in Calanus congeners (Copepoda, Crustacea) from the Arctic Ocean

“…However, in metazoan identification it is still in its infancy. Nevertheless, successful species identification of specimens has been achieved from a large variety of taxonomic groups such as different crustaceans (Bode et al, 2017; Hynek et al, 2018; Kaiser et al, 2018; Kürzel et al, 2022; Laakmann et al, 2013; Paulus et al, 2022; Rossel et al, 2019; Rossel & Martínez Arbizu, 2018b, 2019), fish (Maász et al, 2017; Mazzeo et al, 2008; Rossel et al, 2020; Volta et al, 2012), cnidarians (Holst et al, 2019; Korfhage et al, 2022), molluscs (Hamlili, Thiam, et al, 2021; Wilke et al, 2020) and a large variety of insects, preferentially those which are potential disease vectors (Dieme et al, 2014; Hasnaoui et al, 2022; Loaiza et al, 2019; Mathis et al, 2015; Nabet et al, 2021; Nebbak et al, 2017; Yssouf et al, 2014).…”

Unsupervised biodiversity estimation using proteomic fingerprints fromMALDI‐TOF MSdata

“…The data set is a matrix containing specimens as rows and m/z values (molecule mass/charge) as columns. Values in these columns indicate peak intensities after standard workflow consisting of data trimming, smoothing, normalization, noise reduction, peak detection, and peak binning (Bode et al ; Kaiser et al ; Holst et al ). In the following, these data will be referred to as raw data.…”

Species Delimitation of Hexacorallia and Octocorallia Around Iceland Using Nuclear and Mitochondrial DNA and Proteome Fingerprinting

“…After the study of Holst et al (2019), this is the second study employing MALDI-TOF MS for delimitation of cnidarians.…”

“…MALDI-TOF MS is a widely used method in species discrimination for fungi (Patel, 2019), viruses (Calderaro et al, 2014), and bacteria (Yang et al, 2018). Successful species discrimination has also been shown for insects (Ulrich et al, 2017), fish (Mazzeo et al, 2008), crustaceans Paulus et al, 2021;Kürzel et al, 2022), and some cnidarians, such as Staurozoa (Holst et al, 2019).…”