Proparadilepis plegadissaakovae Kornyushin et Greben, 2014

Kornyushin, V. V. & Greben, О. B., 2014, A New Genus And Species Of Cestodes (Cyclophyllidea, Gryporhynchidae) From Ciconiiform Birds, Vestnik Zoologii 48 (6), pp. 483-494 : 486-492

Proparadilepis plegadissaakovae Kornyushin et Greben , gen. et sp. n.

S y n. Paradilepis plegadis Saakova, 1952 , nom. nud. (Smogorzhevskaya, 1976; Kornyushin et al., 2004; Kornjushin et al., 1984).

T y p e s p e c i m e n. Holotype, СН2 , Ukraine, Odessa Region Danube Delta, 1948 (original label: “ Paradilepis plegadis Saakova , Type of species, Danube, 1948, collected by Saakova ”). The type material is deposited in the helminthological collection of I. I. Schmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine, Kyiv.

T y p e h o s t. Plegadis falcinellus L.

S i t e. Small intestine.

T y p e l o c a l i t y. Ukraine, Odessa Region, Danube Delta, Lake Yalpuh (45° 25´N, 28° 37´E).

D e s c r i p t i o n ( fig. 1–3 )

Length of moderately contracted strobila 80 mm (90 mm), greatest width — 3.5 mm. Scolex flattened, 848 (800) wide 1 mm long. Suckers almost rounded 230 ќ 240, or slightly oval, 200 ќ 250 (200 ќ 252). Scolex of living cestode apparently was spheroid, with deep cup-shaped suckers. Rostellum short, mushroom-shaped, 320 long. Apex of rostellum greatly expanded, 360 (320) in diameter. Hooks in double row. Total number of available hooks 33 (33), 18 small hooks, three large hooks apparently absent (one of them visible on strobila), therefore, crown consists of 36 hooks. Posterior (small) hooks 52 (up to 51) 1 long; length measurements of hook positioned at angle to surface of rostellum about 42 (37). Blade of small hooks 20–21 long, handle 23–26 long. Handle with secondary tissue epiphysis making hook 5 longer. Guard almost rectangular to hook axis, slightly bent to blade, 16 long. Oval epiphysis on guard, 13 ќ 16. Shape of anterior (large) hooks differing a little from that of small hooks. Total length of large hooks 69–73 (up to 51), blade 26 long, handle 31 long, guard 18 long. Oval epiphyses on end of handle and guard of both large and small hooks. Median anterior hook 21(15) long, on upper part of rostellum, presumably damaged. In view of fact that hooks of scolex are measured on permanent slide in Canada balsam, it is possible that specified sizes of hooks slightly differ from real hook sizes.

Borders of rostellar sac not clearly visible. Zone of more intensively stained tissue shows that rostellar sac reaches to level at middle of suckers. Rostellar apparatus similar to cyclusteroid’s, but with less observable two muscular superficial layers, diagonal fibres not seen.

Scolex without sharp constriction gradually passing into neck. Part of strobila without genital primordial 1.5 mm long, situated behind posterior part of suckers, with width about 700. Anterior part of strobila without external segmentation. Transverse folding of cuticle forms false segments. Strobila consists of 380 proglottides, (the part without external segmentation is excluded). In anterior part, false segments can contain up to 20 genital primordia; in posterior part 3–5 genital primordia per false segment. Borders between proglottides become distinct at 7–8 mm from scolex. In these proglottides testes reach maximum development and start to disappear. Segmentation clearly visible in part with maximum developed ovary and vestigal testes (at distance c. 15 mm from scolex).

Рис. 1. Proparadilepis plegadissaakovae gen. et sp. n. голотип, общий вид. Масштабная линейка 1 см.

Рис. 2. Proparadilepis plegadissaakovae gen. et sp. n. Голотип: 1 — сколекс; 2 — хоботковые крючья; 3 — яйцо; 4 — гермафродитный членик; 5 — маточный членик. Масштабные линейки: 1, 4, 5 — 100 мкм; 2, 3 — 50 мкм.

Proglottides wider than long. Hermaphroditic proglottides 1.3–1.4 mm wide and 100 long. Female proglottides 1.4–1.9 ќ 0.1–0.15 mm. Pre-gravid proglottides 2.8–3.5 mm wide and 0.1–0.2 mm long, then size becomes 1.5–1.9 ќ 0.5–0.7 mm. Gravid proglottides 2.4–3.3 mm wide and 1.2–1.5 mm long.

Diameter of ventral osmoregulatory canals 78–104; transverse anastomoses observed. Dorsal osmoregulatory canals not distinct. Genital ducts pass dorsal to longitudinal osmoregulatory canals. Genital pores unilateral.

Four testes in each proglottis, usually arranged in line, one poral and three aporal to female gonads. Middle aporal testis often shifting in anterior or posterior direction. Sometimes, two testes may be poral and two aporal; rarely three poral and one aporal. Testes transversely-oval, lateral often drop-shaped. Developed testes 105–133 ќ 57–78; poral testis smaller, 78–84 ќ 63–78 (51–59 ќ 80–85). External vas deferens very wide (7), forming some large coils between poral testis and distal part of cirrus-sac; coils arranged along anterior margin of proglottides. Cirrus-sac not crossing poral osmoregulatory canals, 147–198 ќ 26–40 when fully developed. Internal vas deferens forming enlargement in aporal part of cirrus-sac, resembling internal seminal vesicle. Invaginated cirrus seen at 5–8 from proglittis margin. Evaginated cirrus 38–57 long, conical. Basal part of cirrus 16–21 in diameter, distal part narrowing to 10–11; cirrus covered with small spines, 1–2 long, densely arranged, staggered. Numbers of rows of spines on cirrus unclear, at least 10–12 spines present per diagonal row. Genital atrium simple, opens at some distance (up to 150) of lateral proglottides margin.

Vagina opens behind and ventrally to cirrus-sac. Copulative part of vagina funnelshaped, with circular musculature, 21–32 in diameter, 78–80 long. Conductive part of vagina 13–16 in diameter, with thick wall and narrow canal (approx. 2–3). In many proglottides vagina partly or completely overlapping cirrus-sac. Female and male gonads appear together. Female gonads attain maximum development in 15–20 mm behind scolex, then disappear. Ovary appears primarily as narrow transverse body with thickening on ends; mature ovary forming two wings; each of them divided to 2–5 large lobes; isthmus hardly visible, at level of vitellarium. Ovary 700–900 wide. Vitellarium compact, transversely-oval, 128–197 ќ ќ 39–79. Female gonads fill entire median field of proglottis. Early development of uterus not traced. Apparently uterus appears as sac ventrally to ovary, copping its shape. When eggs start to fill uterus, peripheral aporal part of uterus becomes perceptible, later medial part perceptible, then poral part. With further maturation, shape of uterus changing. At first uterus becomes solid sac-like, then it deforms making branches. In more developed proglottides, uterus branches converge and uterus looks like simple sac with evaginations, which are especially numerous in lateral parts of uterus; uterine wall thick and well-marked. Gravid uterus occupies almost entire proglottis. Oncosphere oval 13–16 ќ 18–26. Embryonic hooks 12–13 long, blade 4. Embryophore spherical, thin, smooth, 26–29 in diameter. External envelope deformed. Approximate size of eggs 47–53 ќ 57–67. Eggs arranged closely to each other.

D i f f e r e n t i a l d i a g n o s i s

The new species is similar to cestodes of the genus Paradilepis group “ scolecina ” ( Bona, 1975) in the scolex armament, in the number of testes and in the shape of the young uterus.

The group “ scolecina ” includes cestode species parasitizing birds of the family Threskiornithidae , i. e. Paradilepis patriciae Baer et Bona, 1960 from Platibis flavipes in Australia, 3 cestode species from the cormorants, i. e. P. scolecina (Rudolphi, 1819) Hsü, 1935 , P. delachauxi (Furmann, 1909) Joyeux and Baer, 1935 and P. longivaginosus (Mayhew, 1925) Freeman, 1954 , and 2 cestode species from Pandion haliaetus , i. e. Paradilepis rugovaginosus Freeman, 1954 and P. simoni Rausch, 1949 .

The new species differs from P. patriciae by larger general length of the strobila (80 mm vs 2–5 mm), by larger number of rostellar hooks (36 vs 20) and by the length of rostellar hooks. Besides, hooks in P. patriciae are larger: 88–101.5 and 60.5–74.5 vs 69–73 and 52. It also differs from this species also by a particular structure of the copulatory apparatus. The cirrus of P. patriciae is covered with large sparse spines.

From all but two species of Paradilepis group “ scolecina ”, including the parasites of ichthyophagous birds, the new species differs by the shape of the rostellar hooks, by long strobila with more numerous proglottides and by other morphological peculiarities. The exceptions are P. rugovaginosus and P. simoni . Both species are the parasites of Pandion haliaetus from North America and possibly are synonymous. Scolex of these cestodes is armed of 32 and 36 hooks. The hooks’ shape is similar to that of the new species. The length of the rostellar hooks in P. rugovaginosus and P. simoni , 98–103 and 68–72 respectively, is larger than that of the new species. The latter differs also by the morphology of the strobila: the cirrus of P. rugovaginosus is larger and covered with long spines, vagina is with vaginal cilia. Besides, P. simoni has 5 testes ( Rausch, 1949), whereas P. rugovaginosus has 4 testes, sometimes 3 or 5 ( Freeman, 1954).

The species of the genus Paradilepis group “ urceus ” have hooks of different shape: the blade of hooks, especially large ones, is longer than handle. This distinguishes them, including those parasitic in Ciconiiformes ( Paradilepis diminuta Huey et Dronen, 1981 ; P. lloydi (Southwell, 1926) Spassky, 1954 ; P. maleki Khalil, 1961 ; P. urceina Bona, 1975 ; P. urceus (Wedl, 1885) Joyeux et Baer, 1950 ) from the new species.

Рис. 3. Proparadilepis plegadissaakovae gen. et sp. n. Голотип (копулятивный аппарат): 1 —частично инвагинированный циррус; 2 — циррус и вагина. Масштабные линейки: 1 — 50 мкм; 2 — 100 мкм.

Рис. 4. Вооружение сколекса: 1 — Paradilepis scolecina (Rudolphi, 1819) Hsü, 1935 ; 2 — Moshonalepis macrosphincter (Fuhrmann, 1909) comb. n.; 3 — Proparadilepis plegadissaakovae gen. et sp. n. Масштабные линейки 100 мкм.

The new species is similar to Ascodilepis transfuga (Krabbe, 1869) Guildal, 1960 (syn. Paradilepis transfuga (Krabbe, 1869) Baer et Bona, 1960) from Ajaia ajaia in Brasil. It also differs from A. transfuga by larger general length of the strobila (8 mm vs 2–5 mm), by larger number of rostellar hooks (36 vs 20) and by the length of rostellar hooks. A. transfuga has smaller hooks (55–61 and 42–44). The new species is different from this species by a particular structure of the copulatory apparatus. The cirrus armament of A. transfuga is similar to the cirrus armament of Proparadilepis plegadissaakovae gen. et sp. n., but A. transfuga has pseudocirrus and pseudovagina, that are absent in the new species.

Some characteristics of P. plegadissaakovae gen. et sp. n. are similar to some in cestodes of the genus Dendrouterina . Species of the genus Dendrouterina were divided by F. V. Bona (1975) into two groups: “ herodiae ” and “ macrosphincter ”, which we consider as valid genera as stated above. The new species is similar to the species of the group “ macrosphincter ” (corresponding to the genus Mashonalepis ) by a number of characters, especially by the ratio between the lengths of small and large hooks.

Mashonalepis macrosphincter (Fuhrmann, 1909) comb. n. (= Dendrouterina macrosphincter (Fuhrmann, 1909) Baer et Bona, 1960), parasitic in Ardeidae from Europe, Asia, Africa, undoubtedly belongs to this group.

Five more species ( D. ardeae (Rausch, 1955) Mahon, 1956 parasitic in Ardea herodias from the USA; D. arcana Bona, 1975 parasitic in Ardea purpurea from Slovakia; D. crassirostrata (Fuhrmann, 1908) Baer et Bona, 1960 parasitic in Tigrisoma lineatum from Brazil; D. australiensis Baer et Bona, 1960 parasitic in Ardea pacifica and Ardea novaehollandiae from Australia; D. junonia Bona, 1975 parasitic in Ardeidae sp. from Madagascar) presumably may be assigned to Mashonalepis , but they need additional morphological studies. These species have 20 hooks with length different from that in the new species and tens of the testes in each proglottis.

D. ardeae and D. junonia are similar to the new species by the shape of the rostellar hooks, since the handle of hooks is relatively short. D. ardeae is a typical Dendrouterina by all other characters. D. junonia is incompletely described. The affiliation of D. junonia to the genus Dendrouterina requires studying of additional new material.

The species of the genus Dendrouterina group “ herodiae ” are characterized by great difference between the length of small and large hooks. This distinguishes these species from a new species.

We have studied specimens of Mashonalepis macrosphincter (Fuhrmann, 1909) comb. n. and Paradilepis scolecina from our collection and compared them to the new species. Essential differences between the new species and the members of these genera were found ( fig. 3 ).

Figures

Fig. 1. Proparadilepis plegadissaakovae gen. et sp. n. Holotype, general view of cestoda. Scale bar 1 cm.

Fig. 2. Proparadilepis plegadissaakovae gen. et sp. n. Holotype: 1— scolex; 2 — rostellar hooks; 3 — egg; 4 — hermaphrodyte proglottid; 5 — gravid proglottid. Scale bars 1, 4, 5 — 100 µm; 2, 3 — 50 µm.

Fig. 3. Proparadilepis plegadissaakovae gen. et sp. n. Holotype (copulatory apparatus): 1— cirrus partly invaginated; 2 — cirrus and vagina. Scale bars: 1 —50 µm; 2 —100 µm.