Paroniella, Fuhrmann, 1920

Beveridge, Ian & Smales, Lesley R., 2017, Cestode Parasites (Platyhelminthes) of Rodents from New Guinea and Adjacent Islands with a Redescription of Paroniella blanchardi (Parona, 1897) (Davaineidae), Records of the Australian Museum (Rec. Aust. Mus.) 69 (6), pp. 451-460 : 456

Paroniella sp.

Figs. 10–14

Material examined. From Melomys lutillus (Thomas, 1913) ( Papua grassland melomys): Ohoilin Village , Kei Besar, Maluku Province, 5°36'S 133°03'E (W23784) ; from Rattus feliceus Thomas, 1920 (spiny Seram Island rat): Piliana Village , Seram, Maluku Province, 3°15'S 129°30'E (W23778) ; from Rattus mordax (Thomas, 1904) ( eastern New Guinea rat): Kalo-kalo Village , Fergusson Island, Milne Bay Province, 9°25'S 150°26'E (W23786) ; from Rattus tanezumi Temminck, 1844 (oriental house rat): Ohoilim Village , Kei Besar, Maluku Province, 5°36'S 133°3'E (W23815) .

Description

Description based on 4 specimens from R. feliceus : small cestodes; scolex 0.30–0.45 (0.36, n = 4) in diameter; retracted rostellum 0.09–0.10 (0.10, n = 3) in diameter; suckers 0.09–0.12 (0.10, n = 6) in diameter, lacking spines; rostellar hooks c. 80 in number; hooks 0.015 –0.020 (0.017, n = 5) long; mature segments craspedote, 0.12–0.20 (0.16, n = 5) long, 1.1–1.2 (1.17, n = 7) wide, length: width ratio 7.3; genital pores unilateral; genital atrium close to anterior margin of segment; cirrus sac small, pyriform, 0.10–0.14 (0.12, n = 5) long, 0.04–0.06 (0.05, n = 5) wide, not reaching osmoregulatory canals; seminal vesicles absent; vas deferens coiled runs along anterior margin of segment; c.10 poral and c. 20 aporal testes respectively, crossing dorsal but not ventral osmoregulatory canals; testes 0.030 –0.045 (0.040, n = 5) in diameter. Vagina opens to genital atrium posterior to cirrus sac; distal region of vagina enlarged; seminal receptacle c. 0.05 × 0.02; female genitalia in midline; ovary with poral lobe 0.05–0.11 (0.08. n = 5) × 0.04–0.06 (0.05, n = 5), slightly larger than aporal lobe, 0.04–0.08 (0.05) × 0.03–0.06 (0.05); vitellarium reniform, posterior to ovary, 0.06–0.10 (0.07, n = 5) × 0.04–0.06 (0.05, n = 5); Mehlis’ gland not seen. Gravid segments 0.25–0.30 (0.28, n = 3) long, 1.0–1.6 (1.3, n = 3) wide, length: width ratio 4.6; eggs in individual capsules; egg capsules 0.030 –0.050 (0.035, n = 5) in diameter, eggs 0.015 –0.025 (0.019, n = 5) in diameter; egg capsules extend beyond osmoregulatory canals; on both sides of segment; osmoregulatory canals paired; ventral canal external, 0.025–0.03 (0.028, n = 3) in diameter; dorsal canal internal to ventral canal, narrower, c. 0.01 in diameter, more sinuous; narrow transverse canal, 0.010 –0.015 (0.012, n = 3) in diameter connects ventral canals at posterior margin of each segment; in many segments, lateral extension of transverse canal present, of variable size.

Remarks. These cestodes belong within Paroniella , but have smaller rostellar hooks than P. blanchardi . As there are no other species of this genus known to be parasitic in rodents ( Sawada, 1964), it is assumed that it represents an undescribed species or possibly even more than one species. Unfortunately, the current material is inadequate to allow a full formal description and for this reason the species has not been named. The description has been restricted to specimens from a single host species as some variation in testis number and distribution was noted in material from other hosts.

Figures

Figures 10–14. Paroniella sp. (10) scolex, dorsoventral view; (11) scolex, apical view; (12) rostellar hooks; (13) mature segment; (14) gravid segment. Scale bars: Figs. 10, 11, 13, 14— 0.1 mm; Fig. 12—0.01 mm.