Molecular phylogeny of Ceriantharia (Cnidaria: Anthozoa) reveals non-monophyly of traditionally accepted families

Abstract

We present an integrative study with molecular phylogenetic reconstructions and morphological assessment across the three Ceriantharia families: Arachnactidae, Botrucnidiferidae and Cerianthidae. The Arachnactidae specimens (Isarachnanthus spp.) form a well-supported clade, whereas Cerianthidae and Botrucnidiferidae are not recovered as monophyletic. Consequently, the validity of the suborder Spirularia is questioned. Cerianthus was recovered as polyphyletic and Ceriantheomorphe may prove to be a junior synonym of Cerianthus. The taxonomic position of Cerianthus cf. mortenseni is also discussed. All specimens identified on morphology as belonging to Pachycerianthus are recovered as a clade. Further revision of taxa within Ceriantharia is necessary. Molecular phylogenetic analyses based on six mitochondrial or nuclear loci place Ceriantharia as sister to Hexacorallia s.s., but with no significant support relative to an alternative hypothesis that it is the sister taxon to Octocorallia. Further molecular sequence data and taxon sampling will be needed to resolve the position of Ceriantharia.

A cnidarian phylogenomic tree fitted with hundreds of 18S leaves

“…and the genus Cerianthus are non-monophyletic. These problems echo results of previous molecular phylogenetic relationships among Ceriantharia, which generally find conflict between taxonomic groups and phylogenetic results (e.g., Stampar, et al 2012; Stampar, et al 2014; Forero Mejia, et al 2020). The disconnect between taxonomy and phylogeny in both the phylogenomic and 18S data are paralleled in recent discoveries of significant plasticity in morphology within the life history of a species and persistent taxonomic confusion, even at a narrow geographic scale (reviewed in Stampar, et al 2016).…”

A Cnidarian Phylogenomic Tree Fitted With Hundreds of 18S Leaves

“…and the genus Cerianthus are nonmonophyletic. These problems echo results of previous molecular phylogenetic relationships within Ceriantharia, which generally find conflict between taxonomic groups and phylogenetic results (e.g., Forero Mejia et al, 2020;Stampar et al, 2012Stampar et al, , 2014. The disconnect between taxonomy and phylogeny in both the phylogenomic and 18S data are paralleled in recent discoveries of significant plasticity in morphology within the life history of a species and persistent taxonomic confusion, even at a narrow geographic scale (reviewed in Stampar et al, 2016).…”

Cerianthus lloydii (Ceriantharia: Anthozoa: Cnidaria): New Status and New Perspectives

“…Ceriantharia, also known as tube anemones, is a well-defined [ 1 ] and relatively ancient [ 2 ] group of marine benthic organisms. Ceriantharians are solitary anemone-like anthozoans known from the intertidal zone to the abyssal depths of all oceans [ 3 ]. Tube anemones have a rather uniform appearance, with an elongated column and flattened oral disk with two crowns of tentacles [ 3 , 4 ].…”

“…Ceriantharians are solitary anemone-like anthozoans known from the intertidal zone to the abyssal depths of all oceans [ 3 ]. Tube anemones have a rather uniform appearance, with an elongated column and flattened oral disk with two crowns of tentacles [ 3 , 4 ]. Tube anemones ordinarily inhabit long fibrous tubes that give their vernacular name [ 1 , 4 ].…”