Review ofOnyxCobb (Nematoda: Desmodoridae) with description of two new species from the Yellow Sea, China

Abstract

Genus Onyx Cobb, 1891 has been reviewed and 19 valid species including two new species have been reported in the world. Two new species, Onyx rizhaoensis sp. nov. and Onyx minor sp. nov. from the Yellow Sea coast are described and illustrated. In addition to the genus characters Onyx rizhaoensis sp. nov. has relatively long cephalic setae; a single loop-shaped amphidial fovea; 12 S-shaped tubular precloacal supplements in 10 + 2 arrangement, posterior 10 closely spaced, anterior two set apart; female vulva situated at almost midpoint of the body. Onyx minor sp. nov. is characterized by a relatively small body for the genus (body length usually shorter than 800 μm); gubernaculum slender parallel to spicules and with a hooked dorsal apophysis; 12 S-shaped tubular precloacal supplements fairly evenly spaced; female vulva situated at about midbody. At the same time, a dichotomous key for Onyx males is proposed.

Onyx disparamphis sp. n. (Nematoda, Desmodorida) from South Korea with a taxonomic review of the genus

“…Onyx rizhaoensis Huang & Wang, 2015 . Huang & Wang, 2015 : 1128–1129, Figs 1, 2 (males, females); Yellow Sea, intertidal sandy sediment.…”

“…However, the number of species grows, especially by the exploration of tropical meiofauna, that leads to increasing complexity in species identification. Coupled with new species description, several reviews of the genus Onyx were suggested ( Blome & Riemann, 1994 ; Nasira, Rehmat & Shahina, 2011 ; Armenteros, Ruiz-Abierno & Decraemer, 2014 ; Huang & Wang, 2015 ). Increase in number of species requires periodical taxonomic revisions with proper adjustment of species composition and construction of improved keys for species identification.…”

A new species of free-living marine nematode (Nematoda: Chromadoridae) from the East China Sea

“…Currently, about 7,000 species of free-living marine nematodes have been described (Appeltans et al 2012), and more than 260 species have been identified from China. Of these, 77 species are endemic to the China Sea (Huang, 2008;Huang & Zhang, 2014). During an investigation of biodiversity of free-living nematodes in the East China Sea in February 2013, we recovered seven species of the Family Chromadoridae (Chromadorita sp, Dichromadora affinis Gagarin et Thanh, 2011, Ptycholaimellus spp.…”