Graphonema, Cobb, 1898

Shimada, Daisuke, Tsujimoto, Megumu & Watanabe, Kentaro, 2019, A New Free-living Marine Nematode Species of the Genus Graphonema (Nematoda: Chromadorida: Chromadoridae) from Antarctica, Species Diversity 24 (1), pp. 61-67 : 66

Key to species of Graphonema

1 Gubernaculum (whole length) much longer than a half of spicule length···················································································· 2

– Gubernaculum either almost equal to or shorter than a half of spicule length ············································································ 3

2 Body shorter than 2.0 mm, spicules approximately 1.5 abd long······································································ G. mediterraneum

– Body longer than 2.5 mm, spicule length equal to abd··································································································· G. arcticum

3 Spicules shorter than 30 µm ······································································································································· G. parafricanum

– Spicules equal to or longer than 40 µm ··············································································································································· 4

4 Tail 7–9 abd long in both sexes ································································································································· G. northumbriae

– Male tail either equal to or shorter than 6 abd··································································································································· 5

5 Gubernaculum thin, weakly developed ·············································································································································· 6

– Gubernaculum and lateral pieces well-developed····························································································································· 7

6 Spicule length almost equal to abd ······································································································································· G. georgei

– Spicules twice as long as abd·················································································································································· G. vulgare

7 Proximal end of spicules with a set-off capitulum········································································································· G. amokurae

– Proximal end of spicules with a not set-off capitulum························································································································ 8

8 Gubernaculum without tiny projections at distal end····································································································· G. scampae

– Gubernaculum with tiny projections at distal end···························································································································· 9

9 Body shorter than 1.5 mm, lateral differentiation absent ························································································· G. metuliferum

– Body equal to or longer than 2.0 mm, lateral differentiation present······················································· G. antarcticum sp. nov.