Redescription of the hagfishes (Myxinidae: Eptatretus) from southern Africa

ABSTRACT

The hagfishes of the genus Eptatretus (Myxinidae) from southern Africa are known from three poorly studied species: Eptatretus hexatrema, a common species from Namibia and South Africa; Eptatretus profundus, known only from the holotype collected off Cape Point (South Africa); and Eptatretus octatrema, known from two syntypes from the Agulhas Bank (South Africa). Taxonomic, morphological and distributional information about these three species are reviewed and updated based on the examination of additional specimens collected in South African waters. Eptatretus hexatrema differs from all congeners by having six pairs (rarely seven) of gill apertures arranged in a straight line, 3/2 multicusp pattern of teeth, total cusps 44–49, trunk pores 53–60, total pores 93–107, preventral length 45.1–57.4% TL, tail length 11.6–14.3% TL, tail depth 5.7–8.1% TL, and two bilaterally symmetrical nasal-sinus papillae. Eptatretus octatrema differs from all congeners by having usually eight (some specimens with seven) pairs of gill apertures arranged in a straight line, 3/2 multicusp pattern of teeth, 42–46 total cusps, 22–26 prebranchial pores, 63–68 trunk pores, 104–117 total pores, and two bilaterally symmetrical nasal-sinus papillae. Eptatretus profundus differs from all congeners by having five pairs of gill apertures arranged in a straight line, 3/2 multicusp pattern of teeth, total cusps 42–46, prebranchial pores 12–15, branchial pores 4–5, trunk pores 48–52, tail pores 15–17, total pores 81–86, and body depth at PCD 7.0–9.7% TL. An identification key for the hagfishes from southern Africa is provided and the conservation status of E. octatrema, a species considered to be Critically Endangered, is discussed in light of the new findings.

RESPONSIBLE EDITOR:

• Christopher Kenaley

KEYWORDS:

• Africa
• conservation
• Eptatretus
• hagfish
• Myxinidae
• redescription

Acknowledgements

I am grateful to the following curators and collection managers for providing specimens, data and/or literature: Mark McGrouther (AMS), James Maclaine (BMNH), Hiromitsu Endo (BSKU), Dave Catania and Mysi Hoang (CAS), Roger Bills and Wouter Holleman (SAIAB), Michael Bougaardt (SAM), Ralph Foster (SAMA), H. J. Walker (SIO) and Jeff Williams (USNM). I also thank Michael Bougaardt and Roger Bills for providing lab space and logistical support during my visit to the South African Museum (Cape Town) and the South African Institute for Aquatic Biodiversity (Grahamstown), respectively. I extend my gratitude to Bafo Konqobe and Yuyani Hanisi (SAIAB) for laboratory assistance; Elaine Heemstra (SAIAB), Rob Leslie (Department of Agriculture, Forestry and Fisheries, South Africa), Oddgeir Alvheim (IMR), and Peter Southwood (iSpot) for providing hagfish photos; Fabio Carocci (FAO) for preparation of the distribution map; Ana Petry (UFRJ) for translating German literature; and Luciano Fischer (UFRJ) for figure enhancements. I also thank Fabio Di Dario (UFRJ), John McCosker (CAS) and one anonymous referee for critically reviewing this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author.

ORCID

Michael Maia Mincarone http://orcid.org/0000-0003-0780-7854