Gendria sp.

Moravec, František & Jirků, Miloslav, 2017, Some nematodes from freshwater fishes in central Africa, Folia Parasitologica (033) 64, pp. 1-39 : 20-21

Gendria sp.

Figs. 16–18

Description. Male (body fragment with missing posterior end). Body elongate, whitish, with smooth cuticle; length of available body fragment 9.6 mm, maximum width 231. Anterior end rounded, cephalic vesicle reduced to inflation of cuticle surrounding mouth anterior to oesophagus, 15 high ( Figs. 16A–E , 17A–E , 18A–C ). Mouth almost circular, with 6 rounded inner lip-like lamellae (2 dorsal, 2 ventral and 2 lateral) giving it hexagonal appearance; in addition, there is circumoral row of small denticles below these lip-like structures ( Figs. 16D , 17C–E , 18A– C ). Bottom of buccal cavity formed by 3 flat triangular oesophageal lobes, corresponding to 3 sectors of oesophagus, with somewhat forwardly oriented tips appearing as small, moderately developed oesophageal teeth ( Figs. 16D , 17D , 18B ). Narrow lateral alae about 750 long present, starting just posterior to anterior extremity and extending posteriorly approximately to middle of oesophageal posterior extension ( Figs. 16B,C,E , 17A–C ). Oesophagus muscular, 544 long, somewhat expanded at both ends ( Fig. 16A,C,E ); its width at anterior end 75, near posterior end 102; minimum width of oesophagus 51. Nerve ring encircles oesophagus at 190 from anterior extremity. Deirids small, situated at level of posterior oesophageal extension ( Figs. 16B , 17B,C , 18D ). Excretory pore located some distance posterior to end of oesophagus and deirids, at 748 from anterior end of body. Posterior end of body absent.

Female. Not known.

Host: Freshwater butterflyfish Pantodon buchholzi Peters (Osteoglossiformes: Pantodontidae ).

Site of infection: Intestine.

Locality: Forest stream near Mongambe research camp, 02°55'26''N; 16°23'24''E (Congo basin), DSPA, Central African Republic (collected 18 September 2012) .

Prevalence and intensity: 1 fish infected/3fish examined; 1 nematode.

Deposition of voucher specimen: IPCAS N-1141.

Remarks. The general structure of the mouth of this nematode resembles that of Gendria spp. and also the presence of circumoral denticles shows its affinity with two representatives of this genus ( G. longispiculata and G. sanghaensis ) described in this paper. However, in contrast to the type species of Gendria ( G. tilapiae ) and some other congeners, the present nematode possesses six well-developed circumoral lip-like structures, its cephalic vesicle is reduced to a cuticular inflation surrounding the mouth and it has distinct cervical lateral alae.

Of the species of Gendria parasitising African freshwater fishes, cervical alae were described only in G. thysi , a parasite of the catfish Parauchenoglanis punctatus (Claroteidae) in the Democratic Republic of the Congo ( Puylaert 1970a), but this species differs from the present specimen mainly in having much broader cervical alae and a bifid dorsal oesophageal tooth in the mouth. Since no quimperiid has so far been reported from fishes of the order Osteoglossiformes , it is highly probable that the specimen from P. buchholzi represents a new species. However, a prerequisite for the species description and its taxonomic evaluation is a new collection of specimens from this host species. Therefore, for the time being, the present specimen is tentatively assigned to Gendria as Gendria sp.

Figures

Fig. 16. Gendria sp. from Pantodon buchholzi from Pantodon buchholzi Peters, male. A, B, C – anterior end of body, lateral, ventral and sub-dorsoventral views, respectively (internal structures not illustrated in B); D, E – cephalic end, apical and sub-dorsoventral views, respectively.

Fig. 17. Gendria sp. from Pantodon buchholzi Peters, scanning electron micrographs of male. A – anterior end, subventral view (arrow indicates lateral ala); B – same, lower magnification; C – anterior end, lateral view (arrow indicates lateral ala); D – cephalic end, subapical view from lateral side (arrow indicates protruding dorsal oesophageal tooth); E – cephalic end, subapical view oriented dorsoventrally. Abbreviations: a – amphid; b – cephalic papilla; c – deirid; e – excretory pore.

Fig. 18. Gendria sp. from Pantodon buchholzi Peters, scanning electron micrographs of male.A – cephalic end, apical view; B – mouth, apical view; C – mouth with visible circumoral row of denticles, subapical view; D – deirid. Abbreviations: a – amphid; b – cephalic papilla.