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, Nematocarcinusevansi 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: Nematocarcinusevansi and N.machaerophorus were recorded for the second time since their original descriptions and newly found from the South China Sea. Nematocarcinusexilis, 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.