On the Oxyurid Nematode, Pharyngodon mamillatus in the Skink, Novoeumeces schneideri (Lacertilia: Scincidae) from Egypt Author(s): Omar Sayed Omar Amer and Charles R. Bursey Source: Comparative Parasitology, 75(2):333-338. 2008. Published By: The Helminthological Society of Washington DOI: http://dx.doi.org/10.1654/4338.1 URL: http://www.bioone.org/doi/full/10.1654/4338.1 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/ terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Comp. Parasitol. 75(2), 2008, pp. 333–338 Research Note On the Oxyurid Nematode, Pharyngodon mamillatus in the Skink, Novoeumeces schneideri (Lacertilia: Scincidae) from Egypt OMAR SAYED OMAR AMER1,3 AND CHARLES R. BURSEY2 1 Zoology Department, Faculty of Science, Al-Azhar University (Assiut Branch), Assiut 71524, Egypt (e-mail: marzoukmo@yahoo.com) and 2 Department of Biology, Pennsylvania State University, Shenango Campus, Sharon, Pennsylvania 16146, U.S.A. (e-mail: cxb13@psu.edu) In Egypt, P. mamillatus was first found in Novoeumeces sp. by Baylis (1923) and, later, by Myers et al. (1962) in N. schneideri. Both Moravec et al. (1987) and Ashour et al. (1992) redescribed P. mamillatus from the ocellated skink, Chalcides ocellatus, collected in Cairo, Egypt. Al-Shareef and Saber (1995) also found this species during a helminth survey of the skink C. ocellatus from Cairo. The purpose of this study is to provide additional descriptive (scanning electron microscope [SEM]) information about various body regions of this nematode species, especially differences in male and female lip morphology. Nematodes were removed from the rectum of naturally infected N. schneideri collected from the Marsa Matrouh Governorate (Egypt). They were washed in 0.7% saline solution, relaxed in hot 70% ethanol, fixed in 70% ethanol, cleared in lactophenol, and photographed with a Carl Zeiss 25 microscope. Ten specimens were measured; all measurements are in millimeters unless otherwise specified. For SEM, nematodes were fixed in cold 5% glutaraldehyde in 0.1 M cacodylate buffer for 24 hr., washed in 0.1 M sodium cacodylate buffer (pH ¼ 7.4) 3 times (15 min each), and treated with osmic acid for 2 hr. After washing 3 times in buffer, specimens were dehydrated through a graded ethanol series and dried at 308C for 30 min. After drying, specimens were mounted with silver paint on holders, coated with a layer of gold under vacuum, examined, and photographed using a JEOL JSM-540 LV SEM at 15 kV. Important morphological features are illustrated in Figures 1–23. Nine of 9 (100%) of Novoeumeces schneideri individuals collected from Marsa Matrouh Governorate, Egypt, were found to be infected with the nematode, Pharyngodon mamillatus (range ¼ 5 to 15). Pharyngodon mamillatus is a small oxyurid nematode with a transversely striated cuticle; striations at 0.013 intervals (Figs. 1, 5, 7, 8, 19). The mouth is surrounded by 6 small lips: in females, lips ABSTRACT: Nine specimens of Schneider’s skink, Novoeumeces schneideri (Linstow, 1897) Baylis, 1923 were collected during April 2005 from Marsa Matrouh Governorate, Egypt, and examined for helminths. More than 100 individuals of the oxyurid nematode, Pharyngodon mamillatus, were recovered from the rectum of all 9 (100%) hosts (intensity ¼ 5 to 15). Additional morphological information of the excretory pore, vulva, eggs, and lips were revealed using scanning electron microscopy. KEY WORDS: Pharyngodon mamillatus, Pharyngodonidae, Novoeumeces schneideri, Scincidae, Lacertilia, Egypt, scanning electron microscopy. During a helminthological investigation of the scincid lizard, Novoeumeces schneideri, collected on April 2005 in Marsa Matrouh Governorate, Egypt, 9 of 9 (100%) lizards were found to harbor more than 100 nematodes fitting the description of Pharyngodon mamillatus (Linstow, 1879) Baylis, 1923. Diesing (1861) established the genus Pharyngodon with Pharyngodon spinicauda (Dujardin, 1845) Diesing 1861 from the intestine of the wall lizard, Podarcis muralis, collected at St. Malo, France, as the type species. Skrjabin et al. (1960) revised the genus to retain only those species in which males have welldeveloped caudal alae, forming a genital bursa enveloping all the anal papillae, and females having the vulva in the anterior half of the body. Bursey and Goldberg (1996, 1999) reported the number of Pharyngodon species as 29 and 30 species, respectively. Pharyngodon mamillatus was originally described from Novoeumeces schneideri from Algeria (Linstow, 1897) and, later, redescribed from the skink Novoeumeces algeriensis from Morocco (Chabaud and Golvan, 1957). This species has also been reported from central Asia, Libya, Madagascar, Pakistan, Spain, and Tadzhikistan (Skrjabin et al., 1960; Borgarenko and Said-Aliev, 1975; Sharpilo, 1976; Goldberg et al., 2003; Ibrahim et al., 2005). 3 Corresponding author. 333 334 COMPARATIVE PARASITOLOGY, 75(2), JULY 2008 Figures 1–10. Pharyngodon mamillatus. 1. Structure of esophagus and esophageal bulb in female. 2. Excretory pore and vulvar region of female. 3. Anterior end of female showing lips. 4. Excretory pore and vulvar region of female. 5. Cuticular striations and esophageal structure of male. 6. Anterior end of male showing lips. 7. Excretory pore of male. 8. Posterior end of male. 9. Posterior end of female showing tail filament. 10. Egg. (Caa, caudal alae; Cap, caudal papillae; Ep, excretory pore; L, lips; Oe, esophagus; Oeb, esophageal bulb; Pla, posterior lateral alae; Tf, tail filament; Vu, vulva.) RESEARCH NOTES 335 Figures 11–18. Pharyngodon mamillatus. 11. Anterior end. 12. Lips. 13. Amphids. 14. Excretory pore. 15. Vulva. 16. Details of excretory pore and vulvar region. 17. Posterior end of female showing tail filament. 18. Egg. (Cs, cuticular striation; Ep, excretory pore; L, lips; M, mouth; Vu, vulva.) 336 COMPARATIVE PARASITOLOGY, 75(2), JULY 2008 Figures 19–23. Pharyngodon mamillatus. 19. Cuticular striations. 20–21. Anterior end of male. 22–23. Posterior end of male. (Caa, caudal alae; Cap, caudal papillae; Cs, cuticular striation; L, lips; M, mouth; Sp, spicule; Tf, tail filament.). RESEARCH NOTES are thick and rounded into protruding lobes; in males, lips are semicircular with ill-defined lobes (Figs. 12, 21). Tails of females end in smooth, pointed cuticular filaments; tails of males end with sharp cuticular spikes (Figs. 17, 22–23). The excretory pore is elevated and triangular or circular in shape (Figs. 14, 16), situated short a distance behind the esophageal bulb (Fig. 2). Vulva is a transverse, slit-like aperture with elevated lips in the anterior half of body, just behind the excretory pore (Figs. 2, 4, 16). Male (based on 4 specimens): Length, 3.6–4.0 (3.8); width at excretory pore, 0.19–0.22 (0.21). Esophagus (with bulb), 0.57 long, nerve ring and excretory pore lie 0.19 and 1.14, respectively, from anterior end. Lateral alae, single, lined, start a short distance from anterior extremity and extend posteriorly to anterior edge of cloaca; maximum width, 0.056 (Figs. 8, 20, 23). Bursa, membranous, 0.088 3 0.117. A weakly chitinized, triangular piece or rudimentary spicule projects from cloaca, 0.042 long (Figs. 8, 23). Three pairs of cloacal papillae: 1 large adcloacal pair lying to either side of spicule, and 2 postcloacal pairs (Fig. 8, 22–23). Female (based on 6 specimens): Length of gravid female, 5.7–7.3 (6.3); maximum width, 0.44–0.68 (0.59). Esophagus, 0.72–0.897 (0.81) long; terminates in a typical oxyurid bulb. Nerve ring and excretory pore, situated 0.19–0.2 (0.195) and 1.1–1.18 (1.14), respectively, from anterior end. Lateral alae, 2 longitudinal, parallel ridges, separated by cuticular band, starting a short distance behind anterior extremity and extending to anal opening (Figs 1, 2). Vulva, situated just below the excretory pore; 1.16– 1.29 (1.23) from the anterior extremity. Uterus containing numerous, smooth and elongated eggs, 0.13–0.20 3 0.04–0.07 in size; either pole with small and smooth operculum (Figs. 10, 18). Tail filament, 0.33–0.44 (0.39) long (Figs. 9, 17). The present redescription of P. mamillatus corresponds to the main characteristics described by Moravec et al. (1987) and Ashour et al. (1992). These main characteristics include the number of lips, the position of excretory pore and vulva, the shape of egg and caudal alae, and the number and position of anal papillae. There is some variation in measurements between the present specimens and those of Moravec et al. (1987) and Ashour et al. (1992). The most prominent variations in measurement appear in the body length, esophagus length, excretory pore, and vulva distances from the anterior end of worm. Our measurements are longer than those of Moravec 337 et al. (1987) and Ashour et al. (1992), but this may be due to the difference in hosts or histological techniques. Ashour et al. (1992) used SEM on some body regions including the oral region, the cuticle, and the caudal region of male. The present study adds ultrastructural details of the male spicule, the excretory pore, the vulva, the female tail filament, and the egg to our morphological knowledge of this nematode. Scanning electron microscopy by Ashour et al. (1992) did not reveal any differences between the shapes of the lips in male and female specimens, whereas the present study does reveal a difference. In females, the lips are thick, rounded, and protruding; in males, lips are semicircular, ill defined, and not protruding. 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