First records of three Nematocarcinus species (Crustacea, Decapoda, Nematocarcinidae) in the deep-waters of the north-western Pacific

Background During two scientific expeditions in the South China Sea and the Kyushu-Palau Ridge area, several specimens of thread-leg shrimp were collected from deep waters. Amongst them, three species, Nematocarcinus evansi Burukovsky, 2000, N. exilis (Spence Bate, 1888) and N. machaerophorus Burukovsky, 2003 were newly recorded from the north-western Pacific. The morphological features of these specimens are in concordance with the original description. New information Nematocarcinus evansi and N. machaerophorus were recorded for the second time since their original descriptions and newly found from the South China Sea. Nematocarcinus exilis, collected from the Kyushu-Palau Ridge area, represents a great distribution expansion from the eastern Atlantic and the Mediterranean to the Pacific, making it the fourth Atlantic-Pacific distributed Nematocarcinus species. Their detailed morphological characteristics, colour patterns and partial sequences of the COI and 16S rRNA genes are provided, respectively.

Automated summary

This study reports the collection of thread-leg shrimp specimens from the South China Sea and the Kyushu-Palau Ridge area. Three species, Nematocarcinus evansi, N. exilis, and N. machaerophorus, were newly recorded from the north-western Pacific. Nematocarcinus evansi and N. machaerophorus were recorded for the second time since their original descriptions and newly found from the South China Sea. Nematocarcinus exilis, collected from the Kyushu-Palau Ridge area, represents a significant distribution expansion from the eastern Atlantic and the Mediterranean to the Pacific.