Neotegorhynchus cyprini

Description: Male. Trunk fusiform, 3,750 - 6,900 (5,320) long, in anterior part covered with tegumental spines arranged in single field 280 – 350 long, the same width on ventral and dorsal sides, posterior end rounded (Figs. 1 A, 3 D, E). Maximum width of trunk at level of testes, 600 – 880 (804). Spines in 24 longitudinal rows, 6 – 8 in each row (Fig. 1 B). Length of spines 25 – 30 (27). Proboscis cylindrical, at an obtuse angle to axis of trunk ventrally, 900 – 1,800 (1218) × 120 – 190 (170), armed with 14 longitudinal hook row of 19 – 21 (20) hooks each (Figs. 1 B – D, 3 A). Ventral hooks larger than dorsal. Size of hooks and roots decrease from anterior to posterior, 11 – 15 anterior hooks on ventral side and 10 – 13 with dorsal have simple roots directed to base of proboscis, other hooks without roots (Figs. 1 C, D, 2 C, D, 3 A – C, F). Size of hook blades giving in Table. 2. Proboscis receptacle with bi-layered muscular walls, 1,530 - 1,860 (1,730) long, goblet-shaped widened to 170 – 280 (218) in anterior third, its rear cylindrical part 80 – 220 (153) wide. The thickness of the outer muscular layer of the proboscis receptacle, 35 – 63, exceeds that of the inner, 20 – 30. Cerebral ganglion, 130 – 150 (140) × 45 – 100 (78), in anterior third of proboscis receptacle, more precisely, in posterior part of its goblet widening. Neck short, 110 – 200 (163). Lemnisci ribbon-like, long, 2,700 – 2,750 (2,717) × 100 – 115 (112), form loops to the level of the anterior testis (Fig. 1 A). The organs of the reproductive system occupy slightly more than half the body in its posterior part. Testes oval, one after another without interval, large, 800 – 1,800 (1,117) × 390 – 560 (458), extended longitudinally (Fig. 1 A). Thin seminal ducts extending from testes to penis. Penis oval, 115 × 92, divided into a head and a body, covered with a thin membrane. Eight cement glands clavate, tender, in two groups of four in each (Fig. 1 A). Two cement channels flow into a spherical cement reservoir with a diameter 140. Saefftigen’s pouch clavate, 410 – 560 (543) long. Reproductive system supported by four pairs of muscles attached to walls of trunk. Shape of muscular part of bursa in the invaginated state repeats shape of females tail end. Genital pore terminal. Female. Trunk 8,730 – 17,700 (12,310) long at maximum width in middle part 1,030 – 1,600 (1,299). Spine zone only in anterior part of trunk. Length of spines 28 – 33 (28). Proboscis 1,000 – 1,800 (1,289) long, 190 – 270 (228) wide, armed with 14 longitudinal hook row of 21 – 23 (21) hooks each. Size of hooks and roots decrease from anterior to posterior, 15 – 18 anterior hooks on ventral side and 12 – 15 with dorsal have simple roots directed to base of proboscis, other hooks without roots. Size of hook blades giving in Table. 2. Proboscis receptacle 2,110 – 3,500 (2,580) long, width in its anterior, goblet-shaped part 300 – 500 (415), in posterior cylindrical part 170 – 250 (222). The thickness of the outer muscular layer of the proboscis receptacle, 43 – 80, exceeds that of the inner, 28 – 63. Neck short, retracted and not visible in all specimens. Lemnisci ribbon-like, long, 6,800 × 180 and 7,300 × 160. Genital tract 720 – 830 (800) long. Vagina without muscular sphincter. In posterior part of trunk, around vagina and partly in the copulatory caudal process, there are fan-shaped muscular genital cells with large nuclei (Fig. 1 J). Eggs spindle-shaped, with polar prolongations of the middle shell, 95 – 103 (98) × 23 – 33 (28) (Figs. 1 F, 2 E). Acanthor 60 – 73 (65) × 15 – 20 (17), with 6 lanceolate embryonic hooks in anterior part (Fig. 1 F). In body cavity of all free mature females fully formed eggs not differing in shape and size from eggs from body cavity of the females that has completed mating. At posterior end of females that completed mating, there were no residues of cement secretions remnants. Caudal end of female pointed, in form of a dome on muscular base, 190 – 220 (200) long, with cement cover that remains from muscular part of male bursa of the complementary form. Genital pore terminal.

Figures 1 ‒ 3, Table 2

Remarks: The specimens in the present study are somewhat smaller than those in the type series (Yin & Wu 1984). However, Yu & Wu (1989) noted that worms can reach different sizes in different hosts; in particular, in the intestine of Coreius heterodon the worms were mature, but their size was much smaller. Furthermore, according to the original description, the hooks on the proboscis of the acanthocephalans of this species are arranged in 12 longitudinal rows, whereas in our material all 21 specimens had 14 longitudinal rows of hooks. In all other characteristics, our material agrees with the original description. The detail of the type specimens were not mentioned in the original description, nor was their deposition indicated. Therefore, we designate one of the specimens collected from Cyprinus carpio from Taihu Hu Lake, Yangtze River basin, Wuxi, China, as the neotype of Neotegorhynchus cyprini n. comb.

Type host: common carp Cyprinus carpio L. (Cypriniformes: Cyprinidae). Type locality: Taihu Lake in Wuxi, Jiangsu Province, China (120 ° 13 ' 50 '' E; 31 ° 32 ' 30 '' N). Site of infection: Intestine. Infection rates: Prevalence, 35 %, intensity, 1 – 14 worms per host. Type-material: Neotype ♂ — deposited in the Helminthological Collection of the Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic, Collection number IPCAS A- 122. Molecular data: The partial SSU rDNA (1757 bp) and the partial mitochondrial COI (656 bp) sequences of Neotegorhynchus cyprini n. comb. were deposited in the GenBank database (Acession No. MK 411441 – MK 411446).