Description, morphometric characterization and distribution pattern of Paradiopatra multibranchiata, a new onuphid (Annelida: Polychaeta) from the tropical eastern Pacific

ABSTRACT

Paradiopatra multibranchiata, an onuphid found commonly in shelf sediments of the tropical eastern Pacific, is described here. It belongs to the group of Paradiopatra species characterized by the presence of branchiae on the most anterior parapodia (chaetigers 2–3), with at least seven filaments when fully developed. The new species closely resembles P. parva, also distributed in the eastern Pacific but in temperate habitats. It can be distinguished from the latter by the presence rather than the absence of eyes, and because it bears the highest number of branchial filaments (up to 37) observed in any Paradiopatra species known so far (14–18 filaments at most). The taxonomic status of the new species is supported by comparative morphometric and multivariate analyses, which also allowed us to verify its differences with P. parva. The branchial development was the most useful character to determine the relationships between the specimens of P. multibranchiata sp. nov., while its separation from P. parva (Wilks’ lambda = 0.060, P < 0.0001) was weighted most heavily by the number of filaments at chaetigers 2 and 10, and the length of the median antenna. An anatomical examination with methylene blue stain and with scanning electron microscopy was carried out to illustrate the ventral glandular pad staining pattern and the features of their cuticular pores.

http://zoobank.org/urn:lsid:zoobank.org:pub:194636C6-A032-4B1F-B0B8-1D494C344623

RESPONSIBLE EDITOR:

• Danny Eibye-Jacobsen

KEYWORDS:

• Polychaeta
• Eunicida
• Onuphidae
• taxonomy
• multivariate analysis
• Mexican Pacific

Acknowledgements

We are grateful to Erika Bistrain-Meza for her assistance with the taxonomic identification. We also thank Leslie Harris, Natural History Museum of Los Angeles County (NHMLA), for the generous loan of the material of Paradiopatra parva from California; Yolanda Hornelas Orozco is acknowledged for her assistance with the SEM microscopy and photography, as well as Arturo Carranza Edwards, as head of the institutional project SEDIMENTO, for inviting us to participate in the ‘Sedimento 1’ oceanographic expedition. We are also grateful to the three reviewers for their careful reviews and helpful remarks.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was conducted and supported by the Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México.