Proc. Helminthol. Soc. Wash. 56(2), 1989, pp. 145-150 Neoentomelas asatoi gen. et sp. n. (Nematoda: Rhabdiasidae) and Hedruris miyakoensis sp. n. (Nematoda: Hedruridae) from Skinks of the Ryukyu Archipelago, Japan HIDEO HASEGAWA Department of Parasitology, School of Medicine, University of the Ryukyus, Nishihara, Okinawa 903-01, Japan ABSTRACT: Neoentomelas asatoi gen. et sp. n. (Rhabdiasidae) and Hedruris miyakoensis sp. n. (Hedruridae) are described from skinks of the Ryukyu Archipelago, Japan. Neoentomelas asatoi from the lung of Ateuchosaurus pellopleurus on Okinawa and Amami-oshima islands is distinguished from all other rhabdiasids in having well- developed dorsoventral lips with posteriorly directed lobulate formations. Hedruris miyakoensis from the stom- ach of Scincella boettgeri on Miyako Island differs from other species of the genus by the simple lateral cuticular structures of the interlabia, eggs without peripheral swellings, absence of preanal unpaired papilla, stout spicules with prominent accessory structure, simple hook of the holdfast, and/or difference in the measurements. KEY WORDS: Neoentomelas asatoi, Rhabdiasidae, new genus, Hedruris miyakoensis, Hedruridae, Nematoda, new species, taxonomy, skink, Ateuchosaurus pellopleurus, Scincella boettgeri, Scincidae, Ryukyu Islands, Japan. There have been only a few records of skink TYPE AND ONLY SPECIES: Neoentomelas asa- parasites in the Ryukyu Archipelago, which con- toi. nects the mainland of Japan and Taiwan. During a survey of the helminth fauna in this region, a Neoentomelas asatoi sp. n. rhabdiasid species of unknown genus and an un- (Figs. 1-5) described species of the genus Hedruris were de- DESCRIPTION: Parasitic females (holotype and tected from skinks. The new genus and new 5 paratypes): With characters of the genus out- species are described herein. lined above. Body small with reddish intestine. Length 2.00 (1.21-2.36) mm, width 68 (55-58) Materials and Methods at nerve ring and 83 (62-88) at vulva (Fig. 1). Skinks were hand-collected, killed with ether, and Cuticle delicate, with adhesive outer surface and their viscera were examined under a dissecting micro- easily separated from subcuticular tissue. Ce- scope. Nematodes were fixed in hot 70% ethanol, cleared in glycerin-alcohol solution, and mounted with 50% phalic end globular, 88 (73-90) long by 101 (85- glycerin jelly for microscopical observation. Figures 99) wide. Buccal capsule 55 (48-60) long by 42 were made with the aid of a drawing tube. Measure- (42-60) wide; wall of buccal capsule thick es- ments given are for the holotype or the allotype fol- pecially dorsoventrally, and slightly indented lat- lowed by range for the paratypes in parentheses, and erally (Figs. 2-4). Esophagus with constricted are in micrometers unless otherwise indicated. middle portion, 182 (163-185) long, anterior portion 47 (39-49) wide, middle portion 26 (23- Results 29) wide and posterior portion 38 (34-42) wide Neoentomelas gen. n. (Figs. 1, 2). Nerve ring 113 (104-120), excretory DIAGNOSIS: Nematoda, Rhabditoidea, Rhab- pore 151 (128-169), and deirids 137 (137-172) diasidae. Parasitic female: Cephalic end sub- from anterior extremity (Fig. 2). Vulva slightly spherical. Massive dorsoventral lips with well- posterior to middle of body, 1.01 (0.64-1.17) developed muscular and hypodermal tissues mm from anterior extremity (Fig. 1). Anterior present. Each lip with 2 double papillae and 2 oviduct directed anteriorly, then flexed poste- minute single papillae; amphids near corners of riorly to join anterior ovary; posterior oviduct mouth. Posterior extremity of each labium pro- directed posteriorly and then flexed anteriorly to jected outwards forming 1 median and 2 lateral join posterior ovary. Both ovaries ending near round lobes. Buccal capsule globular, well-de- vulva. Tail conical, 70 (55-75) long (Fig. 5). Eggs veloped, thick-walled, and slightly indented lat- elliptical, 52-73 by 39-48. erally. Onchia absent. Esophagus club-shaped. HOST: Ateuchosaurus pellopleurus. Vagina weakly developed. Amphidelphic. Eggs SITE IN HOST: Lung. thin-shelled and uncleaved at deposition. Para- LOCALITY: Afuso, Onna-son, Okinawa Is- sitic in the lung of reptiles. land (type locality); Seiphah-Utaki, Chinen-son, 145 Copyright © 2011, The Helminthological Society of Washington 146 PROCEEDINGS OF THE HELMINTHOLOGICAL SOCIETY e o Figures 1-5. Neoentomelas asatoi gen. et sp. n., parasitic female. 1. Holotype, general view. 2. Anterior extremity of paratype, lateral view. 3. Anterior extremity of paratype, apical view. 4. Anterior extremity of paratype, ventral view. 5. Tail of holotype, lateral view. Okinawa Island; Mt. Yuwan-dake, Amami-oshi- Helm. Coll. No. 80623; paratypes, National Sci- ma Island. ence Museum, Tokyo, Japan, NSMT As-1910. DATE OF COLLECTION: 6 May 1987 (at Afuso); REMARKS: Neoentomelas is distinguished 23 May 1987 (at Seiphah-Utaki); 15 July 1981 from other genera of the family Rhabdiasidae in (at Mt. Yuwan-dake). having well-developed dorsoventral lips. The SPECIMENS DEPOSITED: Holotype, USNM species name is dedicated to Mr. Ryuji Asato, Copyright © 2011, The Helminthological Society of Washington OF WASHINGTON, VOLUME 56, NUMBER 2, JULY 1989 147 Okinawa Prefectural Institute of Public Health, extremity. Vulva 0.55 (0.39-0.62) mm from anus who collected the material from Amami-oshima (Fig. 13). Tail 0.51 (0.43-0.49) mm long, with Island. eversible posterior holdfast armed with hook and supported by large musculature (Fig. 13). Hook Hedruris miyakoensis sp. n. 145 (143-150) long (Fig. 14). Surface of holdfast (Figs. 6-16) with numerous transverse rows of pointed spines (Fig. 15). Eggs elliptical, 48-53 by 23-25, with GENERAL: Nematoda, Habronematoidea, plugs on both poles, lacking peripheral swellings, Hedruridae. Body cuticle thick, transversely and containing fully developed larvae (Fig. 16). striated. Cephalic end with 2 large lateral pseu- HOST: Scincella boettgeri. dolabia each bearing 2 sessile and 2 digitiform papillae and amphid (Figs. 7-9). Base of each LOCALITY: The Miyako Plant Garden, Hi- pseudolabium supported by large, posteriorly di- rara-shi, Miyako Island, Okinawa, Japan. rected cuticular ridge (Figs. 8, 9). Dorsal and SITE IN HOST: Stomach. Females attached to ventral interlabia present between pseudolabia, mucosa with holdfast, males coiled around fe- each supported by large, posteriorly directed males. ridge. Each interlabium with a blunt anteriorly DATE OF COLLECTION: 11 June 1988. directed lobe and 2 simple lateral cuticular struc- SPECIMENS DEPOSITED: Holotype and allo- tures (Figs. 8, 9). Esophagus indistinctly divided type, USNM Helm. Coll. No. 80624; paratypes, at nerve ring into anterior muscular and poste- National Science Museum, Tokyo, Japan, NSMT rior glandular portions (Fig. 6). Deirids small, As-1911. spinelike, located slightly posterior to nerve ring REMARKS: Hedruris miyakoensis resembles (Fig. 6). H. pendula (Leidy, 1851) Chandler, 1919, H. MALES (holotype and 3 paratypes): Length longispicula Thomas, 1959, and H. minuta An- 8.90 (8.67-8.92) mm, maximum width 0.19 drews, 1974, among the genus representatives (0.19-0.20) mm. Caudal end of body forming 3 parasitic in terrestrial and freshwater vertebrates or 4 coils. Cephalic diameter 85 (80-88), pseu- in that the eggs lack peripheral swellings and the dolabium 63 (60-65) long. Esophagus 0.73 (0.69- lateral cuticular structures of the interlabia are 0.81) mm long and 78 (63 -75) wide. Nerve ring simple. Hedruris miyakoensis differs from H. 0.22 (0.18-0.21) mm, excretory pore 0.37 (0.31- pendula in having a much smaller body (over 15 0.33) mm, and deirids 0.27 (0.22-0.23) mm from mm long in H. pendula} and in lacking unpaired anterior extremity. Caudal alae absent. Tail 0.47 papilla on the anterior anal lip (cf. Baker, 1986). (0.43-0.47) mm long. Caudal papillae 10-12 pairs Hedruris miyakoensis is also distinguished from distributed as follows: 1 or 2 preanal, 1 adanal H. longispicula and H. minuta by the much larger (absent in 1 specimen), and 7-10 postanal pairs body (male 3.0 mm long and female 4.0-5.0 mm arranged on subventral lines, 1 subdorsal pair long in H. longispicula; male 2.55-3.20 mm long just anterior to terminal pair of papillae. Preanal and female 2.05-2.85 mm long in H. minuta). surface with about 25 rows of scalelike bosses Besides the body size, //. miyakoensis differs in extending from near anus to beginning of caudal that H. longispicula has slender spicules and H. coils of body (Figs. 10,11). Spicules robust, fused minuta has a two pronged hook on the holdfast. in posterior two-thirds, distal ends twisted around each other, 135 (133-158) long (Figs. 10-12). Discussion Accessory sclerotized structure prominent on The representatives of the family Rhabdiasi- ventral side of spicules (Figs. 10, 12). Anus mark- dae Railliet, 1916, are heterogonic parasites found edly large (Fig. 11). in the lungs, body, and pericardial cavities of FEMALES (allotype and 3 paratypes): Length amphibians and reptiles (Anderson and Bain, 9.61 (9.71-9.82) mm, width at midbody 0.30 1982). In this family only 4 genera have been (0.29-0.35) mm, at vulva 0.37 (0.34-0.38) mm. recognized: Rhabdias Stiles and Hassall, 1905, Cephalic diameter 95 (93-107), pseudolabium Acanthorhabdias Pereira, 1927, Entomelas Tra- 80 (88-93) long. Esophagus 0.95 (0.82-0.90) mm vassos, 1930, and Pneumonema Johnston, 1916 long and 78 (78-88) wide. Nerve ring 0.23 (0.23- (Baker, 1980). All of them lack well-developed 0.26) mm, excretory pore 0.34 (0.33-0.40) mm, lips. Neoentomelas is an aberrant rhabdiasid in and deirids 0.28 (0.28-0.31) mm from anterior that it has well-developed dorsoventral lips (cf. Copyright © 2011, The Helminthological Society of Washington 148 PROCEEDINGS OF THE HELMINTHOLOGICAL SOCIETY 16 Figures 6-16. Hedruris miyakoensis sp. n. 6. Anterior part of holotype male, lateral view.