Protochromadora Inglis, 1969: 177.
Diagnosis [modified from Inglis (1969), Warwick and Coles (1975) and Tchesunov (2014)]. Euchromadorinae. Body cuticle with complex heterogeneous ornamentation. Lateral differentiation either present or absent. Amphideal fovea either transverse slit-like without a double contour, or not observed. Buccal cavity with a hollow dorsal onchium and two lateral or ventrosublateral onchia, without rows of denticles. Pharynx without posterior terminal bulb. Spicules not jointed. Gubernaculum containing a dorsal piece and a pair of hammer- or L-shaped lateral pieces. Precloacal supplement absent. Pre- and postcloacal cuticular elevation also absent.
Type species. Graphonema vulgare Cobb, 1898 (originally spelled G. vulgaris).
Other species. Nine species:
1. G. amokurae (Ditlevsen, 1921) Inglis, 1969 = Spilophora amokurae Ditlevsen, 1921 = Euchromadora amokurae Allgén, 1929;
2. G. arcticum (Filipjev, 1946) Warwick and Coles, 1975 = Euchromadora arctica Filipjev, 1946;
3. G. georgei Inglis, 1969;
4. G. mediterraneum (Allgén, 1942) Warwick and Coles, 1975 = Euchromadora mediterranea Allgén, 1942 = Protochromadora mediterranea Inglis, 1969;
5. G. metuliferum Kito, 1981;
6. G. northumbriae Warwick and Coles, 1975;
7. G. parafricanum (Gerlach, 1958) Warwick and Coles, 1975 = Euchromadora parafricana Gerlach, 1958 = Protochromadora parafricana Inglis, 1969;
8. G. scampae (Coles, 1965) Warwick and Coles, 1975 = Euchromadora scampae Coles, 1965 = Protochromadora scampae Inglis, 1969; and
9. G. antarcticum sp. nov.
Remarks. Ten species, including the type species, are valid (Cobb 1898; Wieser 1954, 1959a; Inglis 1969; Gerlach and Riemann 1973; Warwick and Coles 1975; Kito 1981). Graphonema achaeta Platonova, 1971 should be transferred to Endeolophos because of the absence of the lateral pieces of gubernaculum (Platonova 1971). Two specific names, G. pachyderma nom. nud. by Cobb (1898), and G. biseriale nom. nud. by Wieser (1959b; originally spelled G. biserialis) are unavailable (Gerlach and Riemann 1973), because they were published without any description, definition, or bibliographic reference.