Paraquimperia sp.

Moravec, František & Nagasawa, and Kazuya, 2018, Rhabdochona angusticaudata sp. n. (Nematoda: Rhabdochonidae) from the Japanese eel Anguilla japonica, and new records of some other nematodes from inland fishes in Japan, Folia Parasitologica (016) 65, pp. 1-22 : 5-6

Paraquimperia sp. Figs. 4 , 5

Description of nongravid female (1 specimen). Medium-sized nematode with anterior end of body dorsally bent. Anterior part of body with broad (maximum width 54) lateral alae initiating near anterior extremity; behind deirids these become narrower and extend along major part of body as narrow lateral alae ( Figs. 4A–C , 5C ). Body length 9.40 mm, maximum width 218. Oral aperture surrounded by 4 submedian cephalic papillae and 2 lateral amphids ( Fig. 5A ). Inner surface of oral aperture lined with cuticular mound consisting of three (1 dorsal and 2 ventrolateral) sectors; both ends of each sector strengthened to form small tooth-like structure oriented anteriorly; bottom of small buccal cavity formed by 3 flat sectors of oesophagus, each armed with forwardly directed tooth ( Figs. 4C , 5B ). Anterior end of oesophagus forming small pharynx 33 long and 51 wide ( Fig. 4A–C ). Oesophagus consisting of anterior narrower muscular and posterior wider musculo-glandular part; anterior part of oesophagus without pharynx 476 long, 57 wide, posterior part 394 long and 90 wide ( Fig. 4A, B ); entire oesophagus including pharynx 903 long, representing 10% of body length. Nerve ring, deirids and excretory pore 408, 789 and 1,034, respectively, from anterior extremity. Vulva situated in posterior part of body, at 6.96 mm from anterior extremity (at 74% of body length). Vulva slightly elevated. Vagina directed anteriorly from vulva. Uterus empty. Tail straight, conical, 354 long; lateral outlets of phasmids located somewhat behind mid-length of tail, appearing as small lateral papillae.

Host: Japanese eel, Anguilla japonica ( Anguillidae , Anguilliformes ).

Site of infection: Intestine.

Locality : Renjoji River (freshwater middle-ridges), Ainan, Ehime Prefecture, Shikoku, Japan (collected 25 June 2007) .

Prevalence and intensity: 9% (1 fish infected, 47.5 cm TL /11 fish examined, 35.2–53.2 cm TL); 1 nematode.

Deposition of voucher specimen: Not deposited (used for SEM).

Remarks. The general morphology of the only available specimen from A. japonica , especially the presence of wide cervical alae, shape of the oesophagus and the structure of the mouth, shows that it belongs to the quimperiid genus Paraquimperia Baylis, 1934 . Although details of its mouth are not readily visible on the available SEM micrograph ( Fig. 5B ), it is clear that the structure of the mouth is much the same as that of Paraquimperia tenerrima (von Linstow, 1878) (see Fig. 6A,B ).

At present, the genus Paraquimperia contains three valid species, all specific parasites of freshwater eels ( Anguilla spp. ): Paraquimperia africana Moravec, Boomker et Taraschewski, 2000 parasitising Anguilla mossambica Peters in South Africa; Paraquimperia anguillae Karve, 1941 from Anguilla bengalensis (Grey) in India; and Paraquimperia tenerrima [syn. Paraquimperia aditum (Mueller, 1934) ] from Anguilla anguilla (Linnaeus) and Anguilla rostrata (Le Sueur) in Europe and North America, respectively ( Moravec et al. 2000). However, interspecific features are found in males, so that the present single specimen (a nongravid female) from A. japonica in Japan cannot be identified to species by morphological features. We can only speculate that it might belong to the Holarctic species Paraquimperia tenerrima , but it will be necessary to obtain conspecific males from A. japonica to confirm this presumption. Nevertheless, the finding of Paraquimperia sp. in Japan represents the first record of a species of this genus in eastern Asia.

Figures

Fig. 4. Paraquimperia sp., nongravid female from Anguilla japonica Temminck et Schlegel. A, B – anterior part of body, lateral and dorsoventral views, respectively; C – cephalic end, dorsal view; D – vulva, lateral view; E – tail, lateral view.

Fig. 5. Paraquimperia sp. from Anguilla japonica Temminck et Schlegel, scanning electron micrographs of nongravid female. A – cephalic end, sub-dorsoventral view; B – region of mouth, subapical view; C – anterior portion of body, dorsal view (arrow indicates deirid); D – tail, sublateral view. Abbreviations: a – amphid; b – cephalic papilla; c – two tooth-like structures of neighbouring sectors of mouth mound; d – oesophageal tooth; e – lateral alae; o – anus; p – phasmid.

Fig. 6. Paraquimperia tenerrima (von Linstow, 1878) from Anguilla anguilla (Linnaeus), Czech Republic, scanning electron micrographs of mouth. A – apical view; B – subdorsal view. Abbreviations: a – amphid; b – cephalic papilla; c – two tooth-like structures of neighbouring sectors of mouth mound; d – oesophageal tooth.