Graphonema Cobb, 1898

Venekey, Virag, Gheller, Paula F., Kandratavicius, Noelia, Cunha, Beatriz Pereira, Vilas-Boas, Ana Carolina, Fonseca, Gustavo & Maria, Tatiana F., 2019, The state of the art of Chromadoridae (Nematoda, Chromadorida): a historical review, diagnoses and comments about valid and dubious genera and a list of valid species, Zootaxa 4578 (1), pp. 1-67 : 24-25

Genus Graphonema Cobb, 1898

The genus Graphonema was erected by Cobb (1898) when the type species G. vulgare Cobb, 1898 was described from Australian samples. In the same work, G. pachydermum was mentioned, but never described, therefore it is considered a nomen nudum. Cobb (1935) and Johnston (1938) considered Graphonema a synonym of Euchromadora but later Wieser (1954) reinstated the genus and transferred Chromadora sabangensis , Spilophora amokuroides Allgén, 1927 , Spilophora norwegica Allgén, 1932 and Chromadora paraheterophya Allgén, 1932 to it. Also, in Wieser (1954), Chromadora spectabilis Allgén, 1932 was synonymized with G. vulgare and both Spilophora pusilla Allgén, 1947 and Chromadora suilla Allgén, 1947 were synonymized with the recently transferred Graphonema amokuroides . Subsequently, Wieser (1959a) transferred other two species to Graphonema : G. tentabunda , a new combination for Chromadora tentabunda sensu de Man, 1890 , and G. chitwoodi , a new combination for Chromadorita tentabunda sensu Chitwood, 1951 . Also, in Wieser (1959a), two new species were described ( G. flaccida and G. clivosa ) and Chromadorita crassa Timm, 1952 was synonymized with the recently transferred G. tentabunda . In the same year, Graphonema biseriale is cited in Wieser (1959b) but this species was never described, consequently it is also considered nomen nudum. Inglis (1969) described G. georgei and reviewed the situation of many Graphonema species, resulting in the transfer of G. amokuroides , G. clivosa , G. flaccida , G. norwegica , G. paraheterophyla and G. tentabunda to Innocuonema . Also, Inglis (1969) considered that Spilophora amokurae Ditlevsen, 1921 , re-described as Euchromadora amokurae by Wieser (1954), is most probably a Graphonema species, and Euchromadora arctica is incertae sedis between Euchromadora and Graphonema . Inglis (1969) also stated that G. sabangensis should be considered as species inquirendum due to description based only on females, which according to him makes discussion difficult, and C. spectabilis (which was synonymized with G. vulgare ) should be transferred to Innocuonema . Platonova (1971) and Kito (1981) described G. achaeta and G. metuliferum , respectively. Meanwhile, Warwick and Coles (1975) synonymized Protochromadora with Graphonema transferring all species [ P. scampae ( Coles, 1965) ; P. mediterranea ( Allgén, 1942) ; P. parafricana ( Gerlach, 1958) ] and described G. northumbriae . According to Inglis (1969), Graphonema is easily recognized within Chromadoridae looking at the head: distinctly set-off as a swollen, almost globular form, and with very fine dot-like punctations in the cuticle of this region of the body. Inglis (1969) also comments that the cuticle of Graphonema becomes thicker over the region of the pharynx but always remains relatively thin and delicate in appearance when compared to Euchromadora and other close genera.

Diagnosis (modified from Tchesunov 2014): Complex cuticle heterogeneous, structured with hexagonal or ovoid punctuations anteriorly and posteriorly, with slimmer markings restricted to the lateral surface over the middle of the body. Six outer labial sensilla and four cephalic sensilla setiform, arranged in separate circles. Transversally elliptical amphideal fovea with cuticular fringe. Buccal cavity with large, seemingly hollow dorsal tooth, ventrosublateral teeth; rows of denticles absent. No distinct posterior pharyngeal bulb. Gubernaculum with prominent hammer or L-shaped lateral pieces.

Number of valid species: 9.

Genus Graphonema Cobb, 1898

Syn. Protochromadora Inglis, 1969

VALID SPECIES

1. Graphonema achaeta Platonova, 1971 ( Japan Sea)

2. Graphonema amokurae (Ditlevsen, 1921) Inglis, 1969 (Auckland Islands)

Syn. Euchromadora amokurae (Ditlevsen, 1921) Wieser, 1954

Spiliphera amokurae Ditlevsen, 1921

3. Graphonema georgei Inglis, 1969 ( Australia)

4. Graphonema mediterranea ( Allgén, 1942) Warwick & Coles, 1975 (Mediterranean)

Syn. Euchromadora mediterranea Allgén, 1942

Protochromadora mediterranea ( Allgén, 1942) Inglis, 1969

5. Graphonema metuliferum Kito, 1981 ( Japan Sea)

6. Graphonema northumbriae Warwick & Coles, 1975 (Scilly Island)

7. Graphonema parafricana ( Gerlach, 1958) Warwick & Coles, 1975 (Red Sea)

Syn. Euchromadora parafricana Gerlach, 1958

Protochromadora parafricana ( Gerlach, 1958) Inglis, 1969

8. Graphonema scampae ( Coles, 1965) Warwick & Coles (1975) (English Channel)

Syn. Euchromadora scampae Coles, 1965

Protochromadora scampae ( Coles, 1965) Inglis, 1969

9. Graphonema vulgare Cobb, 1898 ( Australia)

SPECIES INQUIRENDUM

1. Graphonema sabangensis ( Steiner, 1915) Wieser, 1954 ( Indonesia)

NOMENA NUDA

1. Graphonema biseriale Wieser, 1959 (Chesapeake Bay)

2. Graphonema pachydermum Cobb, 1898 ( Australia)