Phylogeny and Biogeography of Branchipolynoe (Polynoidae, Phyllodocida, Aciculata, Annelida), with Descriptions of Five New Species from Methane Seeps and Hydrothermal Vents

Johanna Lindgren,Stephané Hourdez,Charlotte A Seid,Greg W Rouse,Avery S Hatch

doi:10.3390/d11090153

Johanna Lindgren, Stephané Hourdez + Show 3 more

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https://doi.org/10.3390/d11090153

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Abstract

The four named species of Branchipolynoe all live symbiotically in mytilid mussels (Bathymodiolus) that occur at hydrothermal vents or methane seeps. Analyses using mitochondrial (COI and 16S) and nuclear (ITS) genes, as well as morphology, were conducted on a collection of Branchipolynoe from Pacific Costa Rican methane seeps and West Pacific hydrothermal vents. This revealed five new species of Branchipolynoe, and these are formally described. The new species from Costa Rica live in three species of Bathymodiolus mussels (also new) at depths ranging from 1000 to 1800 m. Branchipolynoe kajsae n. sp. and Branchipolynoe halliseyae n. sp. were found in all three undescribed Bathymodiolus species, while Branchipolynoe eliseae n. sp. was found in Bathymodiolus spp. 1 and 2, and Branchipolynoe meridae n. sp. was found in Bathymodiolus spp. 1 and 3. Hence, Bathymodiolus sp. 1 hosted all four of the new species, while the other two Bathymodiolus hosted three each. Most mussels contained only one specimen of Branchipolynoe; where there was more than one, these were often a female and smaller male of the same species. The newly discovered species from the West Pacific, Branchipolynoe tjiasmantoi n. sp., lives in unidentified Bathymodiolus at depths ranging from 674 to 2657 m from hydrothermal vents in the North Fiji (Fiji) and Lau Basins (Tonga) and also from New Zealand, Vanuatu, and the Manus Basin (Papua New Guinea). The phylogenetic and biogeographical implications of this diversity of Branchipolynoe are discussed.

Highlights

Scale worms refers to a variety of family-ranked taxa (e.g., Polynoidae Kinberg 1856, SigalionidaeKinberg 1856) placed in Aphroditiformia, which is a relatively large clade of annelids withinPhyllodocida [1,2,3]
All are found in the deep sea at hydrothermal vents, methane seeps, or whale falls
We present molecular sequence data from samples of Branchipolynoe from a series of Pacific Costa Rican methane seeps that have been explored in recent years [36,37], as well as from

Summary

Introduction

Scale worms refers to a variety of family-ranked taxa (e.g., Polynoidae Kinberg 1856, SigalionidaeKinberg 1856) placed in Aphroditiformia, which is a relatively large clade of annelids withinPhyllodocida [1,2,3]. In terms of species richness, Polynoidae is the most diverse of these families, with more than 850 accepted species [4], and these are grouped into many subfamilies. There are 18 named polynoid species that have segmental branchiae. These belong to five genera spread across several subfamilies: Branchinotogluma Pettibone, 1985 [5], Branchiplicatus Pettibone, 1985 [6], Branchipolynoe Pettibone, 1984 [7], Peinaleopolynoe Desbruyères & Laubier, 1988 [8], and Thermopolynoe. Branchipolynoe contains species that are only found living inside mussel mantle cavities. They have very well-developed branchiae, much larger than the other branchiate polynoid species

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