The mitochondrial genomes of Crispatotrochus rubescens and Crispatotrochus rugosus (Hexacorallia; Scleractinia): new insights on the phylogeny of the family Caryophylliidae

Abstract

Background Caryophylliidae is one of the most diverse scleractinian families, however it was recovered as polyphyletic in multiple molecular studies. Recently, the mitochondrial gene order was proposed as a character for a taxonomic revision of the family. Here we describe the rst mitogenome of the caryophylliid genus Crispatotrochus, whose phylogenetic position remains uncertain. Methods and resultsThe complete mitochondrial genomes of Crispatotrochus rubescens and Crispatotrochus rugosus were sequenced, assembled, and annotated. The two mitogenomes are identical and circular, have a length of 16,536 bp, a GC content of 35.9%, and contain 13 protein-coding genes, 2 ribosomal RNAs and 2 transfer RNAs. Both species have a transposition of a three-genes block -cob, nad2, and nad6 -similarly to a group of caryophylliid genera that were recovered as monophyletic and include the type species (Caryophyllia) of the family. The phylogenetic analyses recovered Crispatotrochus within the clade that presents the gene rearrangement and speci cally as sister taxa of the genus Caryophyllia, a result consistent with previous studies and the similar gross morphology of the two genera.Conclusions We determined the mitochondrial genomes of the genus Crispatotrochus to investigate their relations within Scleractinia. Results from this study provide insights on the phylogenetic position of the genus and corroborate that the mitochondrial gene order could be used as taxonomic character for the family Caryophylliidae.

Untangling deep‐sea corals systematics: Description of a new family, Stephanocyathidae (Anthozoa, Scleractinia), through a genomic approach

“…More recently, the more thorough usage of high‐throughput sequencing methods—for example target enrichment and genome skimming—has enabled the access and handling of vast amounts of molecular data (Goodwin et al., 2016; Kulkarni & Frommolt, 2017; Quattrini et al., 2023). Coupling nuclear ultraconserved elements (UCEs) and exon loci and complete mitochondrial (mt) genomes, a recent study showed that all sequenced components of the caryophylliid clade comprising the type genus of the family (i.e., Caryophyllia Lamarck, 1801), have a specific mt genome rearrangement (i.e., a transposition of the gene block containing cob , nad2 and nad6 genes between nad5 5′ and trnW different from the canonical scleractinian mt gene order—gene block located between nad1 and atp6 ) not present in any other sequenced scleractinian taxa (Seiblitz et al., 2022; Vaga et al., 2022). The aforementioned studies recovered the genera Crispatotrochus Tenison‐Woods, 1878, Desmophyllum Ehrenberg, 1834, Premocyathus Yabe & Eguchi, 1942 and Solenosmilia Duncan, 1873 grouping with Caryophyllia in a monophyletic clade that is phylogenetically independent from all the other ‘caryophylliid’ clades recovered so far.…”