Stephonyx californiensis sp. nov. (Amphipoda: Lysianassoidea: Uristidae), a new bathyal scavenger species from the Central Gulf of California, Mexico, and comments on the bathymetric and geographic distribution of the Stephonyx species group

ABSTRACT

A new species of scavenger amphipod of the genus Stephonyx is described and illustrated. The specimen was caught at 1150 m depth with a modified rectangular lobster trap positioned on the sea bottom in the central Gulf of California, Mexico. The new species is characterised by the absence of eyes; the lateral cephalic lobes medially developed and acute; antennae subequal in length; gnathopod 1 chelate, dactylus simple with three distal stout setae, inner margin sinuous with minute setae; gnathopod 2 subchelate, carpus with ventral margin crenulate, propodus subovate, palm deeply excavate, and dactylus slightly shorter than palm; maxilliped inner plate laceolate, with seven marginal nodular robust setae, distally; telson, each lobe with two dorsal robust setae, distal margin truncated, with one penicillate and two simple setae, in addition to two short spines. Stephonyx californiensis sp. nov. is morphologically similar to S. arabiensis, S talismani, S. laqueus and S. perexcavatus. The new species increases the number of Stephonyx species around the world to 14, with one species inhabiting from the continental shelf to abyssal depths (to 3000 m), 11 species occurring in bathyal depths (201–2000 m), and two other species restricted to abyssal depths (2001–4000 m).

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KEYWORDS:

• Deep-sea
• baited trap
• amphipod
• taxonomy

Acknowledgements

The authors thank all crew members, scientists and students who took an active part in the PANDAL research cruise, and Mercedes Cordero Ruiz for preparing Figure 1. Ship time aboard the R/V El Puma was provided by the Coordinación de la Investigación Científica, UNAM, Mexico.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Universidad Nacional Autónoma de México [No award number. Funding of ship time only].