Taenia lynciscapreoli, Haukisalmi, Voitto, Konyaev, Sergey, Lavikainen, Antti, Isomursu, Marja & Nakao, Minoru, 2016

Haukisalmi, Voitto, Konyaev, Sergey, Lavikainen, Antti, Isomursu, Marja & Nakao, Minoru, 2016, Description and life-cycle of Taenialynciscapreoli sp. n. (Cestoda, Cyclophyllidea), ZooKeys 584, pp. 1-23 : 3-10

Taxon classification Animalia Cyclophyllidea Taeniidae

Taenia lynciscapreoli sp. n.

Material.

Adult. Type–material: Holotype MZH 127098 (five slides, including hand–cut transverse sections, and fragments in ethanol). Paratype MZH 127099 (three slides and fragments in ethanol), from the same host individual as the holotype.

Voucher material from Lynx lynx : MZH 127100 (three slides and fragments in ethanol), MZH 127101 (five slides and fragments in ethanol) and MZH 127102 (six slides and fragments in ethanol), Lohja, southern Finland; MZH 127105 (two slides) and MZH 127106 (three slides), Mikhailovskiy raion, Altai Rai, Russia.

Voucher material from Canis lupus (wolf): SVK-2265 and SVK-2581, Mikhailovskiy raion, Altai Rai, Russia.

Other museum specimens from Lynx lynx from Finland (in ethanol): MZH 123001, from Hyvinkää; MZH 123002, from Sauvo; MZH 123003 and 123004, from Mustasaari; MZH 123005, locality unknown.

Other records from Lynx lynx : Kolosovsky and Bolsheukovsky raions, Omskaya oblast’, Western Siberia, Russia (morphological identification), coll. Bykova, 2006 [identified as Taenia pisiformis (Bloch, 1780)].

Type host.

Lynx lynx Linnaeus, 1758, the Eurasian lynx. Other hosts: Canis lupus Linnaeus, 1758, the wolf.

Type locality.

Salo, Perniön Ylikulma (WGS 84: 60°16.948'N; 23°13.288'E), southern Finland.

Site. Small intestine.

Metacestode.

Host: European roe deer Capreolus capreolus (Finland), Siberian roe deer Capreolus pygargus (Russia) and Eurasian elk/moose Alces alces (Finland).

Voucher material.

MZH 127104 (two specimens in ethanol), Alces alces (calf), Hausjärvi, southern Finland; SVK-2344, SVK-2402 (in ethanol), SVK-2458, SVK-2395 (slides), Capreolus pygargus , Russian Far East.

Other museum specimens.

N16553, Museum of All–Russian K. I. Skryabin Scientific Research Institute of Helminthology (Moscow), Capreolus pygargus , Tuva Republic, Southern Siberia, Russia (identified as Taenia hydatigena ).

Site. Liver and lungs.

Diagnosis.

Adults and metacestodes of Taenia lynciscapreoli sp. n. can be separated unambiguously from all other species of Taenia by the shape of their large rostellar hooks, particularly the characteristically short, wide and strongly curved blade. If the large rostellar hooks are missing in adults, Taenia lynciscapreoli may be separated from related species by a combination of morphological features of mature proglottids (see Discussion).

Description.

Measurements are in micrometres if not otherwise stated.

Adult (Figs 2-7; Table 1). Measurements of mature proglottids and scolex are based on specimens from Finland, and other measurements (external features, rostellar hooks, uterine branches, eggs) on combined material from Finland and Russia.

Medium–sized species of Taenia ; length of fully gravid specimens 55-90 cm (n=4). Maximum width of strobila 5-7 mm (n=4). Scolex 1.1 mm (n=2) wide in specimens mounted in Berlese’s medium (BM), 0.85 mm (n=1) wide in specimens mounted in Canada balsam (CB). Maximum diameter of suckers 269-289 in BM (n=7), 213-255 in CB (n=4). Diameter of rostellum 375-425 in BM (n=2), 300-365 in CB (n=2); rostellum larger than suckers. Neck approximately as wide as scolex, of variable length.

Rostellum bearing two rows of hooks; rostellar armature usually incomplete in adult specimens. In combined material, length of large hooks 168-231 (mean=212.2, n=27) and length of small hooks 106-137 (mean=126.2, n=25). Total length and other dimensions of large hooks consistently smaller in specimens from Finland than in those from Siberia and Russian Far East. Large hooks characterized by long, thick and straight handle sometimes provided with apical bulge, relatively short, wide and strongly curved blade and prominent, usually slightly pointed guard. Border between hidden and exposed parts of large hooks marked with distinct oblique ridge. Margin of ridge provided with pits of various sizes at middle of handle; similar but less distinct pits sometimes present at guard portion of ridge.

Proglottids craspedote, but velum poorly developed. Mature proglottids 2.8-5.3 mm (mean=4.3 mm, n=15) wide and 2.0-3.4 mm (mean=2.6 mm, n=15) long, with length/width ratio of 1:1.2-2.6 (mean=1:1.7, n=15) in well–relaxed specimens. Proglottids becoming more elongate posteriorly; fully–gravid proglottids up to 14 mm long, with length/width ratio of 1:4.7.

Genital pores irregularly alternating, positioned in middle of lateral margin of proglottids. Genital atrium weak, usually not protruding, 238-425 (mean=302, n=12) wide at base and 144-264 (mean=186, n=12) deep. Ventral longitudinal osmoregulatory canals 34-110 (mean=75, n=13) wide in mature proglottids, up to 200 in postmature/pregravid proglottids; connected by narrower transverse canals. Dorsal osmoregulatory canals narrow (seen only in transverse sections), running medially to ventral longitudinal canals. Terminal genital ducts positioned between dorsal and ventral longitudinal osmoregulatory canal and dorsal to nerve–cord.

Testes 591-725 (mean=653, n=5) in number, 80-130 in largest diameter, positioned primarily in one dorso–ventral layer. Testicular field widely confluent anteriorly and occupying all parts of median field lacking female organs, except small well–defined region anterior to ovary. Continuous posterior testicular field absent, but sometimes individuals testes positioned posterior to or overlapping vitellarium. Antero–poral testicular field longitudinally as long as postero–poral field (as separated by vas deferens). Testicular field separated from ventral osmoregulatory canals by distinct free space laterally, anteriorly and posteriorly. Cirrus–sac elongate, 340-425 (mean=382, n=11) long and 153-179 (mean=166, n=11) wide in mature proglottids, usually not extending to longitudinal ventral canal; muscle layers of cirrus–sac well–developed. Distal part of ductus cirri armed with delicate hair–like structures. Vas deferens forming few irregular loops inside cirrus–sac, prominently convoluted outside cirrus–sac.

Ovary bilobed, 98-172 (mean=150, n=15) wide and 57-103 (mean=84, n=15) long; lobes of roughly equal size, but antiporal lobe extending slightly more ante riad than poral lobe; ovary does not reach midline of proglottid longitudinally. Vitellarium distinctly elongated transversely, 80-145 (mean=126, n=15) wide and 19-41 (mean=31, n=12) long, slightly narrower than ovary; lateral extremities usually pointed. Vagina opens posterior to male pore, provided by distinct sphincter ca. 5 from distal end of vagina; sphincter ca. 3 long and 6 wide; sphincter sometimes absent or incom plete (present on one side of vagina only). Copulatory part of vagina shorter than cirrus sac, thick–walled, distinctly widened, curved posteriorly; maximum width of copulatory part 94-111 (mean=106, n=10). Proximal vagina narrow, of uniform width, runs posterior to vas deferens, usually slightly undulating, rarely looped. Lumen of vagina lined with delicate hair–like structures almost throughout its length; hairs particularly long in widened copulatory part. Prior to joining seminal receptacle, vagina forms dif ferentiated region, 10-12 long, with tapered lumen lacking hairs. Sperm–filled seminal receptacle elongate, 9-17 (mean=12.4, n=15) long. Mehlis’ gland spherical, 18-22 (mean=19.6, n=11) in diameter. Uterus in pre–gravid and early gravid proglottids with 8-11 primary branches on each side, often with secondary and tertiary bifurcations; lateral branches not reaching ventral osmoregulatory canal; terminal branches usually with multiple anterior or posterior sacculations. Eggs spherical or subspherical, with maximum diameter of 34-39 (mean=36.8, n=26) in whole–mounts. Outer egg shell thick (4.0-4.5), distinctly two–layered.

Metacestode (Fig. 5, Table 1). External features of metacestodes are based on specimens from Finland, and measurements of rostellar hooks on combined material from Finland and Russia (Table 1).

Metacestode is cysticercus. Ethanol–fixed cysticerci with fully–developed rostellar hooks 3-14 mm long and 2-5 mm wide; larger cysticerci with elongate or sac–like posterior bladder and, in one case, with short (8 mm) strobila between bladder and scolex region. Rostellum armed with 30-34 (mean=32.0, n=7) hooks forming two rows. Large hooks 213-238 (mean=225.9, n=27) and small hooks 123-145 (mean=136.7, n=23) long. Average hook dimensions are consistently smaller in specimens from Finland than in specimens from Siberia and Russian Far East. Rostellar hooks of metacestodes are similar in shape to those of adult cestodes.

Distribution.

Eurasia, from Finland to Russian Far East.

Etymology.

The specific epithet refers to the main definitive and intermediate hosts of the new species.