# Hawaiian black coral (Antipatharia) complete mitochondrial genomes have limited phylogenetic signal for taxonomic resolution of species

## TL;DR

This study uses complete mitochondrial genomes to analyze the phylogenetic relationships of Hawaiian black corals, revealing limited taxonomic resolution and highlighting the need for further research.

## Contribution

The study provides the most complete survey of Hawaiian black coral mitogenomes, revealing polyphyly in some families and genera.

## Key findings

- Myriopathidae is monophyletic, but Aphanipathidae and Antipathidae are polyphyletic.
- Cirrhipathes cf. anguina specimens are genetically divergent and may not be conspecific.
- Antipathes and Stichopathes show greater divergence between species than within genera.

## Abstract

Most inferences about black coral (Antipatharia) phylogenetics have relied on a handful of molecular markers from PCR-Sanger methods but recently complete mitogenomes are shedding additional light on relationships. We present the most complete survey of shallow-water to mesophotic Hawaiian black corals (‘ēkaha kū moana) to date based on complete mitogenome sequences. The phylogenetic relationships inferred from whole-mitochondrial phylogenies recover Myriopathidae as monophyletic with Myriopathes and Tanacetipathes as the outgroups to all other Hawaiian black coral taxa. Combining our data with other published mitochondrial datasets for black corals, we find that morphologically similar Cirrhipathes cf. anguina specimens are divergent and may not be conspecifics. Likewise, the genera Antipathes and Stichopathes (family Antipathidae) include species that are more divergent from one another than they are to other genera in family Aphanipathidae. Overall, data show Myriopathidae is a monophyletic family, but the families Aphanipathidae and Antipathidae are polyphyletic, and the genera Antipathes and Stichopathes live up to their reputation as a “taxonomic dumping ground”. These phylogenetic analyses underscore the need for continued research to understand the evolutionary history and phylogenetic relationships for black corals generally and ‘ēkaha kū moana specifically.