Zootaxa, Rhabdias lamothei n. sp. (Nematoda

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Jul 10, 2006 -
Zootaxa 1257: 27–48 (2006) www.mapress.com/zootaxa/ Copyright © 2006 Magnolia Press

ISSN 1175-5326 (print edition)

ZOOTAXA ISSN 1175-5334 (online edition)

Rhabdias lamothei n. sp. (Nematoda: Rhabdiasidae) from Leptodeira maculata (Colubridae) in Mexico, including new records of R. fuscovenosa (Railliet, 1899) Goodey, 1924 ELIZABETH A. MARTQNEZ-SALAZAR & VIRGINIA LEÓN-RÈGAGNON* Laboratorio de HelmintologRa, Instituto de BiologRa, Universidad Nacional Autónoma de México. Apartado Postal 70-153, Coyoacán, México, D. F., 04510. E-mail: [email protected] *Corresponding author: [email protected]

Abstract Rhabdias lamothei n. sp. (Nematoda: Rhabdiasidae) from the lungs of Leptodeira maculata (Colubridae) is described and illustrated. This is the 53rd species assigned to the genus and the first species described from an endemic snake in Mexico. Rhabdias lamothei differs from all other species by having the combination of the following characters: body coiled, truncated anterior end, 6 lips, equatorial vulvae, esophagus length /body length ratio 8.36–12.46 (10.31%), tail length / body length ratio 4.49–12.28 (6.98 %), and principally by the markedly elongated tail with a sharp terminal point. The geographical distribution of R. fuscovenosa is expanded in 13 localities and 6 new host records are provided. Key words: Rhabdias lamothei n. sp., Rhabdias fuscovenosa, taxonomy, Nematoda, Rhabdiasidae, Leptodeira maculata, Colubridae, Mexico

Introduction The cosmopolitan genus Rhabdias Stiles and Hassall, 1905 includes around 52 species, most of which are parasites of amphibians (Ranidae, Bufonidae) and reptiles (Colubridae) (Baker, 1987; Bursey et al., 2003; Goldberg and Bursey, 2005; Kuzmin, 2003; Kuzmin et al., 2003; Kuzmin et al., 2005; Lhermitte-Vallarino and Bain, 2004; Sarkar y Manna, 2004). Eight species have been recorded parasitizing snakes (Bursey et al., 2003), 3 of them are distributed in the Americas, R. eustreptos (MacCallum, 1921) Chitwood and Chitwood, 1934, R. fuscovenosa (Railliet, 1899) Goodey, 1924 and R. vellardi Pereira, 1928.

Accepted by B. Adams: 10 Apr. 2006; published: 10 Jul. 2006

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R. fuscovenosa was described from snakes of Palaearctic colubrids (Baker, 1978, 1987; Chu, 1936; Kuzmin et al., 2003; Reiber et al., 1940); however, this species has been recorded in North America. Jiménez-Ruiz et al. (2002) recorded this species in the Mesa Central of Mexico from Thamnophis eques Reuss, 1834 and T. melanogaster Peters, 1864 (Colubridae). Little is known about the geographical distribution and host specificity of the genus Rhabdias in Mexico (Table 1). During an ongoing inventory of the helminth fauna of reptiles from Mexico, we found an undescribed species of Rhabdias in Leptodeira maculata from the Pacific coast lowlands of northwestern Mexico, and new information about the geographical distribution of R. fuscovenosa.

Material and methods From 2001 to 2004, specimens of Leptodeira annulata (24), L. maculata (17), L. septentrionalis (1), Sibon sartorii (4), Storeira sp. (1), Thamnophis godmani (1), T. melanogaster (3) and T. proximus (1) were collected in Central and Southeast Mexico (Table 2). Reptiles were collected using nets or hooks, placed in herpetological bags for transportation, and killed using an overdose of sodium pentabarbitol and fixed using standard procedures (Simmons, 1985). The body cavity opened and internal organs were examined for helminths. Lung worms were initially placed in saline (0.65%), then killed by immersion in 70% ethanol and later cleared with glycerin. Drawings were made with the aid of a drawing tube. Measurements are given in micrometers unless otherwise stated. Minimum and maximum values are given followed by mean and SD in parentheses. For taxonomic determination at specific level we used original descriptions and specialized literature. For scanning electron microscopy (SEM) study, nematodes were stored in 4% formalin, dehydrated in series of gradual ethyl alcohol and critical point dried with carbon dioxide. Specimens were coated with a gold-palladium mixture and examined in a Hitachi S-2460N scanning electron microscope at 15kV. Abbreviations for museums are as follows. CNHE, Colección Nacional de Helmintos, Instituto de BiologRa, Universidad Nacional Autónoma de México, México City, Mexico; USNPC, United States National Parasite Collection, Beltsville, Maryland; UTA, Herpetological Collection, University of Texas in Arlington, Texas, and MZFC, and MZFC, Museo de ZoologRa, Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, Mexico.. Types and paratypes of nematodes were deposited in the CNHE. Hosts were deposited in UTA (collects: JAC) and MZFC (donations: MZFC ND). Specimens of Rhabdias fuscovenosa (CNHE 3631), R. vellardi (CNHE 142-5), R. eustreptos (USNPC 42118), and R. agkistrodontis (USPNC 92278.02) were also examined during this study for comparison. 28

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Results

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1257 Rhabdias lamothei n. sp. (Figs 1–3) Description Based on 9 parthenogenetic females: Body coiled, elongated (Fig. 1). Outer layers of cuticle not swollen, fine transversal striations on the posterior 2/3 of the body (Fig. 3. C). Length 2.51–3.43 (2.83±0.30) mm, maximum width 127–175 (149±16). Anterior end truncated, posterior end tapered. Oral opening surrounded by 6 lips distributed in two lateral groups of three (Fig. 3. A). Each lip bearing single small papilla. Amphids on lateral lips. Buccal capsule cup-shaped in lateral view, circular in apical view (Fig. 2. A, B), 38–77 (53±2) deep, with 11–19 (15±2) wide. Esophagus slender-club shape, length 255–317 (289±2), 8.36–12.46 (10.31) % of body length (BL). Esophagus width 23–34 (27±3) at anterior end; muscular region 31–38 (36±2) wide; glandular region 27–34 (29±2). Esophageal bulb 42–50 (46±3) wide, inflated corpus absent (Fig. 2. A). Nerve ring at 155–220 (186±2) from anterior end. Excretory pore, located near posterior margin of nerve ring (Fig. 2. A), excretory duct lined with thin cuticle. Pair of excretory glands indistinct. Rectum thick-walled. Intestine wide and filled with brown and black contents, allowing its differentiation from the other internal structures. Vulva equatorial, lips indistinct (Fig 2. C). Distance from the anterior end of the body to vulva 1.19–1.88 (1.43±0.21) mm, 46.24–54.88 (50.41) % of BL. Genital system amphidelphic. Ovaries lying along intestine. Uteri thin-walled. Tail conical, markedly elongated (Fig 2. D, Fig 3. B), 124–375 (200±81), 4.49–12.28 (6.98) % of BL, with sharp terminal point (Fig. 3. C). Few eggs, most of them embryonated, and few near vulva containing larvae 34–65 (53±9) long, 27–58 (33±10) wide (Fig. 2. E).

Taxonomic summary Type host and locality: Leptodeira maculata Hallowell, 1861 (symbiotype JAC 23845), Melaque-Autlán, Road 80, Jalisco, Mexico (19°24’32’’N; 104°40’24’’W, 382m). Other localities: Puerto Vallarta- Las Palmas Road, Jalisco (MZFC 17374) 20°45’15’’N; 105°09’27’’W, 53m. Tepalcatepec-Coalcoman, Road 120, Michoacán (JAC 24798) 19°04’20’’N; 102°54’11’’, 391 m. Tepalcatepec-Apatzingán, Road 120, Michoacán (JAC 24866) 19°12’59’’N; 102°48’52’’W, 384m. Tepic-Aguamilpa Road, Nayarit (JAC 231512) 21°45’22’’N; 104°51’40’’W, 79m. Armería river (tributary), Colima (MZFC 18118) 19°11’31’’N; 103°47’37’’W, 329 m.

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FIGURE 1. Rhabdias lamothei n. sp. A. Body total, lateral view. Scale bar = 0.1mm.

Site of infection: Lungs. Specimens deposited: Holotype, parthenogenic female, Colecci\n Nacional de Helmintos del Instituto de Biología, Universidad Nacional Aut\noma de Mexico, CNHE 5375; paratypes CNHE 5376-5378, 5380; vouchers CNHE 5379, 5381-5384. Etymology: The new species is named after our mentor, Dr. Rafael Lamothe Argumedo, for his contribution to the knowledge of Mexican helminthology. Remarks: Rhabdias lamothei differs from all other species by having the combination of the following characters: body coiled, truncated anterior end, 6 lips, esophagus length / body length ratio 8.36–12.46 (10.31%), tail length / body length ratio 4.49–12.28 (6.98 %), equatorial vulvae, and principally by the markedly elongated tail with sharp terminal point.

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FIGURE 2. Rhabdias lamothei n. sp. A. Anterior end, lateral view. B. Cephalic end, lateral view. C. Vulva region, lateral view. D. Tail end, lateral, view. E. Larval and embrionated eggs, lateral view. Scale bar = 0.1mm (Fig. 1 A, C, D, and E), and 0.05 mm (Fig 1. B).

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FIGURE 3. SEM microphotograps of Rhabdias lamothei n. sp. details of the external morphology. A. Anterior end, subapical view. B. Shape of the posterior end, subventral view. C. Details of the shape tail, markedly elongated subventral view; transversal striations on the posterior end (narrow).

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Of the 17 species distributed in the Americas (7 Nearctic (Bursey et al., 2003; Kuzmin et al., 2003), and 10 Neotropical (Bursey et al., 2003; Goldberg and Bursey, 2005)), only Rhabdias eustreptos, R. fuscovenosa, R. vellardi and R. tobagoensis are similar in the presence of 6 lips and equatorial vulvae as is the condition in R. lamothei. Rhabdias tobagoensis differs from R. lamothei in the body shape (coiled in R. lamothei vs. straight in R. tobagoensis), body size (2.51–3.43 (2.83) mm vs. 7.34–7.56 mm in R. tobagoensis), distribution of the lips (six lateral lips grouped in two groups of three vs. circumoral in R. tobagoensis), in the non swollen nature of the cuticle (inflated cuticle in R. tobagoensis) and host preference (frogs in R. tobagoensis). Rhabdias eustreptos, R. fuscovenosa and R. vellardi are similar to R. lamothei in the host preference (snakes) (Table 3). Rhabdias eustreptos is viviparous and presents a typical corkscrew-shaped tail (Baker, 1978; Bursey et al., 2003; Kuzmin et al., 2003), while R. lamothei presents a tail markedly elongated with sharp terminal point. Rhabdias lamothei and R. fuscovenosa also are similar by the presence of embryonated eggs (Baker, 1978). However, Rhabdias fuscovenosa differs from our material in the body shape, body width, shape of the tail and in the esophagus length/ body length ratio. Rhabdias vellardi is similar in body size (3.0–3.3 mm in R. vellardi while 2.51–3.43 (2.83) mm in R. lamothei), but differs principally in the body shape (coiled in R. lamothei vs. straight in R. vellardi), shape of anterior end (rounded in R. vellardi vs. truncated in R. lamothei), the shape of the tail (blunt tip vs. markedly elongated with sharp terminal point in R. lamothei), the tail length/ body length ratio (4.5–12.3 (7) vs. 4.3–4.2 in R. vellardi), and in the eggs length and number (larger and more numerous in R. vellardi). There are other species that share with Rhabdias lamothei the condition of having 6 lips and equatorial vulva, but are distributed in other geographic realms namely, R. hylae Johnston and Simpson, 1942, distributed in the Australian realm; R. bermani Rausch, Rausch and Atrashkevich, 1984, R. bufonis (Schrank, 1788) Stiles and Hassall, 1905, and R. kurilensis Sharpilo, 1976, distributed in the Palaearctic realm; and finally R. japalurae Kuzmin, 2003 in the Oriental realm. Rhabdias lamothei differs from R. hylae by the presence of an inflated corpus in R. hylae, body shape (coiled vs. straight in R. hylae), host preference (snakes vs. frogs in R. hylae), and geographical distribution (Australian realm in R. hylae). Rhabdias bufonis, R. bermani, and R. japalurae differ from R. lamothei on the body size (more than 6 mm vs. 2.83 mm in R. lamothei), body shape (straight in these species), cuticle inflated in the three species, geographical distribution (Rhabdias bufonis, and R. bermani in the Palaearctic realm), and R. japalurae (Oriental realm), and the host preference (toads in R. bufonis, salamanders in R. bermani, and lizards in R. japalurae). Rhabdias kurilensis is similar to R. lamothei in the host preference (snakes), body shape, and is only slightly larger than R. lamothei (3.4–4.9 mm in R. kurilensis vs. 2.51–3.43 (2.83) mm), however, this species differs in body width (150–190 mm in R.

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kurilenis and 127–175 mm in R. lamothei), eggs size (82–88 x 44–50 in R. kurilensis and 34–65 (53) x 27–58 (33)), the shape of the tail (more elongated in R. lamothei than in R. kurilensis), and their geographical isolation is considerable (Palaearctic realm in R. kurilensis vs. the northwestern limit of the Neotropical realm (according to Morrone (2005)) in R. lamothei) (Table 3).

Rhabdias fuscovenosa (Railliet, 1899) Goodey, 1924 (Fig. 4) = Ascaris humilis (Laidey, 1899) Goodey, 1924 nomem oblitum = Angiostoma fuscovenosum Railliet, 1899 = Strongylus catanensis Rizzo, 1902 = Rhabdias ophida Goodey, 1924 = Rhabdias annulosa Hsu, 1933

Host type and locality: Natrix natrix (France). Previous records in Mexico: CiJnaga de Lerma, Estado de Mexico; Lago de Chapala, Jalisco; Lago de Zacapu, Michoacán: Thamnophis eques Reuss, 1834. Lago de Chapala, Jalisco (CNHE 3631); Lago de Pátzcuaro, Michoacán; Lago de Cuitzeo, Michoacán: Thamnophis melanogaster Peters, 1864 (PerJz-Ponce de Le\n et al., 2001; Jiménez-Ruiz et al., 2002). Present records Leptodeira annulata Linnaeus, 1758: Mex 200 Guerrero-Oaxaca Road, Guerrero (JAC 25789) 16°33’52’’ N; 98°27’59’’ W, 31m. La Victoria, Catemaco, Veracruz (MZFC 18107) 18°22’24.1’’ N; 95°07’44.5’’ W, 300m. L. maculata Hallowell, 1861: Playa Azul, Michoacán (JAC 25530, JAC 25531, JAC 25532) 17°59’08’’N; 102°20’16’’ W, 11m. L. septentrionalis Kennicott, 1859: Cerro San Felipe, Oaxaca (JAC 21498) 17°13’ 44’’N; 96°43’37’’W, 2450 m. Sibon sartorii Cope 1863: Xpujil-Bel-ka Road, Campeche (JAC 24350) 18°37’25’’N; 89°24’45’’W, 241m. Cuetzalan, Puebla (MZFC ND 821) 20°06’54’’N; 97°28’58’’W. Valladolid-Mex Road 18 D, Yucat