Indopolystoma parvum n. gen. n. sp., 2019

Chaabane, Amira, Verneau, Olivier & Preez, Louis Du, 2019, Indopolystoma n. gen. (Monogenea, Polystomatidae) with the description of three new species and reassignment of eight known Polystoma species from Asian frogs (Anura, Rhacophoridae), Parasite (Paris, France) 26 (67), pp. 1-18 : 9-11

Indopolystoma parvum n. gen. n. sp.

( Figs. 7 and 8 ; Table 4 )

urn:lsid:zoobank.org:act:6C7F74C6-BFEE-4277-903B-2A531FD09C63

Synonym: Polystoma sp. of Verneau et al. [ 51], Badets et al. [ 2] and Héritier et al. [ 22].

Type-host: Rhacophorus omeimontis (Stejneger) . Now Zhangixalus omeimontis (Stejneger) [ 21, 27].

Site: Bladder.

Type-locality: Wawu Shan, Hongya Xian, Sichuan province, China.

Collector: Professor Anne Marie Ohler, Muséum National d’ Histoire naturelle ( MNHN), Paris, France.

Type-specimens: Holotype ( MNHN HEL1187 ) and paratype ( MNHN HEL1188 ) deposited in the Parasite Collection , National Museum of Natural History, Paris, France.

Etymology: The species name parvum refers to its small body size.

Description

Description based on two unflattened specimens stained in carmine and mounted in Canada balsam. Body elongate, total length 4714 (4536–4891), including haptor; greatest width 1916 (1701–2130); width at vagina 1402 (1279–1525). Haptor circular in outline, 667 (584–749) long, 1258 (1022–1494) wide. Haptor/total body length ratio 0.14 (0.12–0.165). Suckers 335 (281–389) in diameter. Hamuli 326 (311–340) long; with hook 52 (39–64) long ( Fig. 8A–A ’’’). Marginal hooklet C1 32 long; C2–C8 (19–20) long ( Fig. 8B–B ’’). Mouth ventral, sub-terminal and surrounded by false oral sucker; false oral sucker 395 (358–431) wide. Pharynx pyriform, 191 (187–194) long, 190 (174–205) wide. Oesophagus not visible. Intestine bifurcate with medial diverticula highly branched lacking prehaptoral anastomoses. Caeca confluent posteriorly, extending into haptor forming haptoral anastomosis. Testis lying on body midline anterior to ovary. Seminal vesicle prominent and packed with sperm. Genital bulb slightly sclerotized, medio-ventral, 83 (75–90) in diameter, with eight sclerotized genital spines; genital spines 17 (16–18) long. Ovary prominent, sinistral and packed with oocytes; ovary 545 (483–606) long, 269 (231–306) wide. Ootype well developed. Genito-intestinal canal present on same side of body as ovary, joining intestinal caecum posterior to ovary. Uterus confined to dextral and anterior to ovary holding one egg; egg 221 (219–222) long, 103 (93–113) wide. No intrauterine development of eggs observed ( Fig. 7 ).

Differential diagnosis

Indopolystoma parvum can be easily distinguished from I. viridi and I. elongatum by its body size, haptor shape and general morphology of intestine. This species is much smaller than I. elongatum (4714 µm vs. 14,791 µm) while it is only half the size of I. viridi (4714 µm vs. 8550 µm). It shows haptor sub-spherical (vs. sub-rectangular) and intestinal caeca with haptoral anastomosis. It differs from all other congeners, apart from I. pingbianensis , in lacking medial anastomoses. Indopolystoma parvum is smaller than I. pingbianensis (4714 µm vs. 9428 µm).

Figures

Figure 7. Indopolystoma parvum n. gen. n. sp. from Zhangixalus omeimontis. Dorsal view of holotype. (A) A drawing; (B) A photograph. Scale bar: 1 mm.

Figure 8. Indopolystoma parvum n. gen. n. sp. from Zhangixalus omeimontis. Hamuli and marginal hooklets from holotype and paratype. (A–A’) Holotype; (A’’–A’’’) Paratype; (B) Marginal hooklet C1; (B’) Marginal hooklet C2; (B’’) Marginal hooklet C6 or C7. Scale bar: 100 µm (A–A’’’), 20 µm (B–B’’).