A New Free-living Marine Nematode Species of the Genus Graphonema (Nematoda: Chromadorida: Chromadoridae) from Antarctica Author Shimada, Daisuke Department of Biology, Keio University, 4 - 1 - 1 Hiyoshi, Yokohama, Kanagawa 223 - 8521, Japan E-mail: dsk-shimada @ keio. jp & Corresponding author shimada@keio.jp Author Tsujimoto, Megumu National Institute of Polar Research, 10 - 3 Midori-cho, Tachikawa, Tokyo 190 - 8518, Japan Author Watanabe, Kentaro National Institute of Polar Research, 10 - 3 Midori-cho, Tachikawa, Tokyo 190 - 8518, Japan text Species Diversity 2019 2019-05-25 24 1 61 67 http://dx.doi.org/10.12782/specdiv.24.61 journal article 7111 10.12782/specdiv.24.61 8f13fe75-5503-4124-a1dc-fe32e5fb8120 2189-7301 4585216 705B2008-A817-4DF9-B166-9F7F02AA6495 Key to genera of Euchromadorinae 1 Spicules jointed···························································· Rhips – Spicules not jointed···························································· 2 2 Amphideal fovea with thickened walls looking like a double contour···································································· 3 – Amphideal fovea without thickened walls······················ 4 3 Gubernaculum without lateral pieces · Adeuchromadora – Gubernaculum with lateral pieces ················ Actinonema 4 Pharynx with posterior terminal bulb····························· 5 – Pharynx without posterior terminal bulb······················· 7 5 Gubernaculum without lateral pieces ············ Trochamus – Gubernaculum with lateral pieces ··································· 6 6 Precloacal cuticular elevation present ····· Portmacquaria – Precloacal cuticular elevation absent············ Steineridora 7 Gubernaculum without lateral pieces ········· Endeolophos – Gubernaculum with lateral pieces ··································· 8 8 Buccal cavity with rows of denticles ········· Euchromadora – Buccal cavity without denticles ········································ 9 9 Precloacal cuticular elevation present ··· Parapinnanema – Precloacal cuticular elevation absent····························· 10 10 Amphideal fovea oval ······································ Crestanema – Amphideal fovea either transverse slit-like or indistinct ··········································································· Graphonema