Revue suisse de Zoologie (March 2017) 124(1): 1-8 ISSN 0035-418 Orientatractis brycini sp. nov. (Nematoda: Atractidae) from characiform freshwater fishes in Gabon, Africa David Gonzalez-Solis1’2'* & Jean Mariaux 3,4 1 EI Colegio de la Frontera Sur, unidad Chef urna!. Av. Centenario Km 5.5, Che fumai, Quintana Roo 77014, Mexico 2 Institute of Parasitology, Biology’ Centre of the Czech Academy of Sciences, Branisovskà 31, 370 05 Ceské Budëjovice, Czech Republic 3 Muséum d’histoire naturelle de Genève, CP 6434, CH-1211 Genève 6, Switzerland 4 Department of Genetics and Evolution, University of Geneva, CH-1205 Geneva, Switzerland * Corresponding author, E-mail: [email protected] Abstract: The nematode Orientatractis brycini sp. nov. (Atractidae) is described from the intestine of Brycinus macrolepidotus Valenciennes (Alestidae) and Xenocharax spilurus Günther (Distichodontidae) collected in two localities from Gabon, Africa. The new species is characterized by the presence of four submedian lips with well-sclerotized pieces armed with two recurved pointed spines and one median large spine on their distal part, along with two smaller spines posterior to amphidial pores. It differs from its congeners mainly in the length of both spicules, gubemaculum, presence of two lateral spines posterior to amphids, distribution and number of caudal papillae. An emended generic diagnosis is provided. This is the eighth species in the genus Orientatractis, the fourth from fish hosts and the first from Africa, which expands its geographical distribution. Keywords: New species - nematode - Brycinus - Xenocharax. INTRODUCTION 2002; Gibbons, 2010; Mondai & Manna, 2013). Of these, Proatractis was synonymized with Klossinemella, while The family Atractidae Railliet, 1917 includes 26 ge¬ Cyrtosomum and Pseudatractis were synonymized with nera separable into two groups according to the type Atractis (see Baker, 1987; Moravec & Thatcher, 1997), of ovaries: Atractis Dujardin, 1845, Buckleyatractis although Bursey & Flanagan (2002) retained both genera Khalil & Gibbons, 1988, Cobboldina Leiper, 1911, as valid. Crossocephalus Railliet, 1909, Cyrtosomum Gedoelst, During a short visit to the Muséum d’histoire naturelle de 1919, Diceronema Gibbons, Knapp & Krecek, 1995, Genève in 2012, the examination of parasitic nematodes Grassenema Petter, 1959, Labeonema Puylaert, collected from freshwater fishes in Gabon, Africa, 1970, Labiduris Schneider, 1866, Leiperenia Khalil, revealed the presence of very peculiar atractid specimens. 1922, Klossinemella Costa, 1961, Monhysterides These parasites were found in two characiform fishes, Baylis & Daubney, 1922, Orientatractis Petter, 1966, Biycinus macrolepidotus Valenciennes (Alestidae) and Paraorientatractis Gibbons, Khalil & Marinkelle, 1997, Xenocharax spilurus Günther (Distichodontidae) and Paratractis Sarmiento, 1959, Pneumoatractis Bursey, belong to an unknown species of Orientatractis, which Reavill & Greiner, 2009, Podocnematractis Gibbons, is described herein. Khalil & Marinkelle, 1995, Proatractis Caballero, 1971, Brycinus macrolepidotus and X. spilurus are freshwater Pseudatractis Yamaguti, 1961, Pseudocyrtosomum Gupta fishes that inhabits rivers and lakes in Lower Guinea, & Johri, 1987, Rhinoceronema Mondai & Manna, 2013, from Cameroon to the Chiloango River Basin, the Nile Rhinoclemmysnema Gibbons & Platt, 2006, and Rondonia system and the Democratic Republic of Congo. They Travassos, 1920 are in the monodelphic group; whereas feed on insects, crustaceans and vegetation (Froese & Fitzsimmonsnema Petter, 1966, Nouvelnema Petter, Pauly, 2016). 1959, Probstmayria Ransom, 1907, form the didelphic group (Adamson & Baccam, 1988; Bursey & Flanagan, Manuscript accepted 29.08.2016 DOT 10.5281/zenodo.322659 2 D. Gonzâlez-Soh's & J. Mariaux MATERIAL AND METHODS ratypes (MHNG-INVE-91073) in the Muséum d’histoire naturelle, Geneva. - Paratypes in the Helminthological Fishes were collected by angling in 2 localities from Collection of the Institute of Parasitology, Biology the Franceville area. Southeast Gabon, in November Centre, Czech Academy of Sciences, Ceské Budëjovice 2010. All nematode specimens recovered were washed (Cat. No. N-1072). in physiological saline, fixed in hot 4% formaldehyde solution and cleared in different ratios of glycerine-water Type host: Brycinus macrolepidotus Valenciennes mixture for light microscopy. For scanning electron (Alestidae, Characiformes) (Body length 21.4 cm). microscopy (SEM), specimens were postfixed in 1% Other host: Xenocharax spilurus Günther (Disticho- osmium tetroxide (in phosphate buffer), dehydrated dontidae, Characiformes) (Body length 15.5-20.2 cm). through a graded acetone series, critical-point-dried and sputter-coated with gold; they were examined using Site of infection: Intestine. a JEOL JSM-7401F scanning electron microscope Type locality: Bridge on Ogooué River, Haut-Ogooué, at an accelerating voltage of 4 kV (GB low mode). Gabon (01°38’24”S; 13°31’48”E; elev. 300 m), col¬ Drawings were done with the aid of a camera lucida. lected on 28/11/2010. All measurements are in micrometers, unless otherwise indicated. Scientific names of fishes follow Froese & Other localities: Mpassa River, near Hotel Poubara, Pauly (2016). All collections were made in the frame Franceville, Haut-Ogooué, Gabon (01°37’12”S; ot a Scientific Research Convention between the Centre 13°36’00”E; elev. 300 m), 30/11/2010. International de Recherches Médicales de Franceville Prevalence and intensity: Brycinus macrolepidotus: (CIRMF) and the Muséum d’histoire naturelle de prevalence 25% (1 fish infected/4 examined), mean Genève (MFING) with the research permit AR0017/09/ intensity 24 nematodes (range 24). Xenocharax spilu¬ MESRSDT/CENAREST/CG/CST/CSAR. rus-. 43% (3/7), 4.3 (2-8). Etymology: The specific name relates to the generic TAXONOMIC PART name of the fish host (i.e., Brycinus). Family Atractidae Railliet, 1917 Description Genus Orientatractis Petter, 1966 General: Whitish, small-sized nematodes, with cuticle finely transversely striated. Anterior end rounded, Type species: O. levanhoai Petter, 1966 posterior end with very slender, long, pointed tail (Fig. 1A, E). Oral opening rhomboid or quadrangular, with 2 Emended generic diagnosis: Small nematodes with a lateral and 4 submedian poorly-developed lips (Figs ID, complex structure of the apical extremity. Oral opening 2A, B). Each submedian lip bearing one large spherical surrounded by 6 (2 lateral and 4 submedian) poorly- papilla and external pair of well-sclerotized, recurved, developed lips. One or two circlets of oral papillae. Each pointed spines joined at the base and a single large submedian lip bearing a chitinoid piece formed by two median spine. Lateral lips supporting large amphids; two well-sclerotized, recurved, pointed spines and a single small spines posterior to each amphidial pore present large median spine. Lateral lips small, supporting large (Figs ID, 2A-D). Lateral grooves extending from first amphids; two small spines posterior to each amphidial third of esophagus to posterior end of body, but not pore present or not. Grooves or narrow lateral alae reaching tail tip (Figs IE, G, 2F). Esophagus divided in present, extending from first third of esophagus to a cylindrical corpus, elongated isthmus, and posterior, posterior end of body, but not reaching tail tip. Esophagus well-developed, valved bulb (Fig. 1A, B). Nerve ring divided in a cylindrical corpus, elongated isthmus, and surrounding isthmus at its anterior end. Deirids small, posterior, well-developed or not, valved bulb. Nerve ring knob-like, somewhat anterior or at level of nerve ring surrounding isthmus at its anterior end. Deirids small, (Figs IA, B, 2E). Excretory pore anterior to esophageal knob-like, somewhat anterior or at level of nerve ring. bulb (Fig. 1A, B). Intestine straight. Rectum a hyaline Excretory pore at mid-length of corpus or slightly anterior tube. to esophageal bulb. Tail long and thread-like. Males with Male (22 specimens, measurements of holotype in two unequal, similar spicules and small gubemaculum. parentheses); Length of body 2.58-3.07 (3.04) mm, Females monodelphic, viviparous, with vulva near anus. maximum width 52-93 (72). Length of corpus 130- Parasites of freshwater turtles, frogs and fish. 163 (150), ot isthmus 289-346 (305); entire esophagus 436-507 (455). Width of esophageal bulb 33-47 (43). Nerve ring, excretory pore, and deirids 162-226 (178), Orientatractis brycini sp. nov. 294-350 (310), and 175-199 (189), respectively, from Figs 1-3 anterior end of body. Eight pairs of caudal papillae: 1 Deposition of specimens: Holotype (MHNG- subventral precloacal pair, 3 subventral adcloacal pairs, INVE-91071), allotype (MHNG-INVE-91072) and pa- close to each other (one pair anterior to cloacal opening, New Atractidae nematode from African fish 3 m p 0 0 1 Fig. 1. Orientatractis bry>cini sp. nov. (A) Whole body of male, lateral view. (B, C) Anterior end of body, lateral views. (D) Cephalic end, apical view. (E) Posterior end of female, lateral view. (F) Gubernaculum, lateral view. (G) Posterior end of male, lateral view. (H) Spicules, lateral view. 4 D. Gonzälez-Soh's & J. Mariaux Fig. 2. Orientatractis biycini sp. nov., SEM micrographs. (A, B) Cephalic end, subapical and apical views, respectively (asterisks indicate single median spine). (C) Detail of lateral lip, amphid and lateral spines, apical view. (D) Cephalic end, sublateral view (asterisks indicate single median spine). (E) Deirid. (F) Anterior end of body (arrow indicates groove-like lateral ala). Abbreviations: a - amphid, b - cephalic submedian papilla. Is - lateral paired spine, ss - submedian paired spine. New Atractidae nematode from African fish 5 one at same level and one posterior to it), 4 postcloacal 1969; Gonzalez-Solis & Moravec, 2004; Gibbons & pairs (first pair of postcloacals lateral, second and third Platt, 2006; Bursey et al, 2014; Moravec et ai, 2015). pairs subventral and close to each other, fourth pair Even though the type species of the genus was not subdorsal) (Figs 1G, 3A). Pair of small, lateral outlets reviewed, we decided to emend the generic diagnosis, (probably representing phasmids) between pairs 3 and 4 based on the already described species and present of postcloacals (Fig. 3A, E). Single left-shifted papilla data, since several important features were not on anterior cloacal lip weakly-developed (Fig. 3C, D). included in the original description (see Petter, 1966). Spicules unequal, similar, well-sclerotized. Left and right Morphological features as the structure of the oral spicules 130-158 (148) and 75-90 (83) long, respectively. opening, presence of deirids, among others, were Both spicules with transverse striations along their incorporated to the diagnosis for making it easier to lengths; proximal ends slightly expanded, distal ends distinguish Orientatractis from closely related genera sharply pointed (Fig. IG, H). Gubemaculum 29-39 (37) (e.g., Klossinemella and Paraorientatractis) within the long, well-sclerotized, proximal end rounded, with deep Atractidae. Thus, Orientatractis and Paraorientractis depression; distal end pointed and slightly ventrally have four bicomate submedian structures surrounding curved (Fig. IF). Tail 207-257 (229) long, with dorsal mouth, whereas Klossinemella shows eight pairs; the groove-like structure (Fig. 3B). two first genera differ in the number of lips (6 vs. 4) and Female (13 gravid specimens; measurements of allotype presence of ornamentations on the dorsal surface of body in parentheses): Length of body 2.50-3.61 (3.30) mm, in Paraorientatractis. These changes do not modify the maximum width 60-129 ( 109). Length of corpus 126-170 systematic position of the genus. (161), of isthmus 294-355 (318); entire esophagus 443- The four bicomate structures along with a pair of spines 509 (479). Width of esophageal bulb 34-50 (43). Nerve posterior to amphidial pore are only present in O. biycini ring, excretory pore, and deirids 158-221 (217), 292-347 sp. nov., O. hamabatrachos, and O. leiperi; while in (331), and 196-205 (-), respectively, from anterior end O. asymmetrica, O. campechensis, O. chiapasensis, of body. Vulva with anterior lip slightly elevated, near O. levanhoai, O. mekongensis are lacking. the posterior end of body, 2.19-3.18 (2.91) mm from Orientatractis biycini sp. nov. shows similar body length anterior end of body, somewhat anterior to anal opening to that of O. chiapasensis, and is near the lower size (Figs IE, 3F). Distance anus-vulva 39-72 (44). Vagina range of O. campechensis, O. leiperi and O. levanhoai, muscular, anteriorly directed. Uterus containing fully whereas the remaining three species (O. asymmetrica, developed larvae 673-1 176 (927) long; some females O. hamabatrachos, O. mekongensis) have larger bodies. with developing eggs 236-305 x 93-110 (236-242 x 93- Flowever, O. biycini sp. nov. differs from all species 94). Tail 270-388 (348) long, with pore-like phasmids within the genus in the size of both spicules (except in between first and second thirds of tail length (Fig. IE). O. hamabatrachos), gubemaculum and number and distribution of caudal papillae (see Table 1). Remarks The new species shares some similarities with Petter (1966) erected the genus Orientatractis to allocate Paraorientatr actis semiannulata Gibbons, Khalil & nematodes with a particular structure of the oral opening, Marinkelle, 1997, a nematode of Podocnemis unifilis specifically the presence of symmetrical groups of 3 Troschel (Testudines) in Brazil (Gibbons et ai, 1997). sclerotized posteriorly directed spines surrounding Both species harbour identical shape and structures mouth. Currently, this genus includes 7 valid species, surrounding mouth, such as each submedian lip with a namely: O. asymmetrica Gibbons & Platt, 2006 in pair of recurved pointed spines and single median spine Rhinoc/emmyspulcherrima Gray (Testudines) from Costa near their distal margin, along with a pair of smaller Rica, O. campechensis Gonzalez-Solis & Moravec, 2004 spines posterior to amphidial pores. Moreover, both have in Paraneetrophis bifasciatus (Steindachner) (reported as two unequal, striated spicules, similar gubemaculum and Vieja bifasciata) and Cichlasoma pearsei (Hubbs) (both number of caudal papillae. However, they differ in the Perciformes) from Southern Mexico, O. chiapasensis ornamentations on the dorsal surface of body and striated, Gonzalez-Solis & Moravec, 2004 in Theraps intermedins broad, well-developed lateral alae in P. semiannulata. (Günther) (reported as Vieja intermedia) and Tomocichla Caballero-Rodrlguez (1971) described Proatractis tuba (Meek) (both Perciformes) from Southern Mexico, parvicapiticoronata from the tortoise Staurotypus O. hamabatrachos Bursey, Goldberg & Kraus, 2014 in triporcatus in Veracruz, Mexico. Later, this species was Austrochaperina basipalmata (van Kämpen) (Anura) transferred to Klossinemella as K. parvicapiticoronata by from New Guinea, O. levanhoai (type species) in Moravec & Thatcher ( 1997). Gonzalez-Solis & Moravec Indotestudo elongata (Blyth) (reported as Testudo (2004) stated that it probably belongs to Orientatractis elongata) (Testudines) from Vietnam, O. leiperi Buckley, according to the shape of spicules, number and 1969 in Podocnemis vogli Müller (Testudines) from distribution of caudal papillae and structure of the anterior Colombia, and O. mekongensis Moravec, Kamchoo end, but until the type material of K. parviticoronata & Pachanawan, 2015 in Pangasius bocourti Sauvage is re-examined, it should be retained within the genus (Siluriformes) from Thailand (Petter, 1966; Buckley, Klossinemella. 6 D. Gonzâlez-SoHs & J. Mariaux Fig. 3. O) ientatractis brycini sp. nov., SEM micrographs. (A) Posterior end of male, sublateral view (arrows indicate caudal papillae). (B) Dorsal surface of male tail. (C, D) Region of cloaca, ventral views (arrow indicates left-shifted unpaired papilla). (E) Posteiior end of male, lateral view (arrowhead indicates phasmids). (F) Region of anus and vulva, lateral view. Abbreviations: c - anus, g - groove-like dorsal structure, v - vulva. New Atractidae nematode from African fish 7 Table 1. Comparison of some selected measurements of the valid species o['Orientatractis around the world; measurements are in micrometers, unless otherwise stated. Body length (mm) Spicule length Gubemaculum length Caudal papillae* male female right left O. asymmetrica 4.1-4.3 3.7-5.5 86-104 220-239 56-66 4: 2: 3 + 1 O. brycini sp. nov. 2.6-3.1 2.5-3.6 75-90 130-158 29-39 1:3: 4 O. campechensis 3.0-3.5 3.3-4.3 84-106 430-506 62-74 0: 5:4 + 1 O. chiapasensis 2.7-3.0 2.0-3.8 60-68 204-238 44-49 0: 5: 4 + 1 O. hamabatrachos 3.2-4.3 3.4-4.9 79-98 146-165 55-67 2: 1: 5 + 1 O. leiperi 3.0-3.9 2.7-4.3 160 470 76 3: 1: 5+ 1 O. levanhoai 3.3 3.4 90 170 40 3: 0: 5 O. mekongensis 5.3-6.6 7.7-8.9 90-105 306-384 33-51 2: 1:5 * pairs of caudal papillae (without considering phasmids): precloacal: adcloacal; postcloacal + single median papilla (left-shifted in O. brycini sp. nov.) Interestingly, O. brycini sp. nov. was found in two fish Blanka Skorikova, both Institute of Parasitology, BC- species of the order Characiformes, but from different CAS, in Ceské Budëjovice for their technical assistance families (Alestidae and Distichodontidae) and sampling and help with drawings and plates. DGS thanks the localities (Ogooue and Mpassa). Despite this, there were Muséum d’histoire naturelle de Genève for invitation no differences in the morphology and biometrical values and support during his stay in Geneva. This survey was among the nematodes from both hosts, although certain partially supported by the Czech Science Foundation morphometric variability always occurs intraspecifically. (Project No. P505/12/G112). Such morphological and biometrical variability which might be associated with local ecological conditions and physiological traits of host species is not uncommon (see REFERENCES Gonzalez-Solls & Moravec, 2004). Adamson M.L., Baccani D. 1988. 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