Acta zoológica lilloana 59 (1-2): 71–82, 2015 71

A new of the (, ), a tararira from the lower Paraná River, in Misiones,

Azpelicueta, M. de las Mercedes1; Benítez, Mauricio F.2; Aichino, Danilo R.3; Mendez, C. M. Damián4 1 Conicet, Div. Zoología Vertebrados, Museo de La Plata, 1900 La Plata, Argentina, [email protected] 2 Laboratorio de Genética Evolutiva (IBS Conicet-UNaM), Félix de Azara 1552, (3300) Posadas, Misiones, Argentina. 3 Proyecto Biología Pesquera Regional (IBS Conicet-UNaM), Rivadavia 2370, (3300) Posadas, Misiones, Argentina. 4 Universidad Nacional de Chilecito, Campus Los Sarmientos S/N, (5360) Chilecito, La Rioja, Argentina.

Abstract — We describe Hoplias mbigua, a new species of the genus from the lower Paraná, in Misiones, with tooth-bearing plates on dorsal surface of basihyal and basibranchi- als and medial margins of contralateral dentaries converging towards the mandibular symphy- sis in ventral view, characters that permit to include the species in the H. malabaricus group. The presence of five brown bands transversely placed on lower jaw distinguishes the new species from its congeners, excluding H. microlepis (vs. lower jaw straight or with small black or brown dots uniformly distributed). The number of circunpeduncular scales in H. mbigua is 20 whereas H. teres and H. malabaricus have 18 circunpeduncular scales and H. microlepis 22-24 and 12-16 gill rakers on first epibranchial (vs. about 9). Hoplias mbigua has convex dorsal profile between head and dorsal fin whereas H. teres has straight dorsal profile. Hoplias mbigua has a large supraopercle, with its anterior margin contacting the in- fraorbitals 5 and 6 whereas H. cf. malabaricus has a short supraopercle, with an anterior margin scarcely extended before anterior opercular margin. Hoplias mbigua has a large tooth- plate on basihyal and basibranchials instead of two lines of tooth-plates at sides of bones in H. cf. malabaricus. Keywords: Characiformes, Hoplias, lower Paraná.

Resumen — “Una nueva especie del género Hoplias (Characiformes, Erythrinidae), una tararira del Río Paraná bajo, en Misiones, Argentina”. Describimos Hoplias mbigua, una nue- va especie del género, procedente del bajo Paraná en Misiones, con dientes en la superficie dorsal de los basibranquiales y basihial y los márgenes del dentario convergiendo hacia la sínfisis mandibular en vista ventral, caracteres que permiten incluirla en el grupo de H. malabaricus. La presencia de 5 bandas pardas transversales en la mandíbula inferior distin- guen esta especie de sus congéneres, excluyendo H. microlepis (vs. mandíbula inferior lisa o con pequeñas manchas negras o pardas uniformemente distribuidas). El número de escamas circunpedunculares en H. mbigua es 20 mientras que H. teres y H. malabaricus tienen 18 y H. microlepis 22-24 escamas circunpedunculares y 12-16 rastrillos branquiales en el primer epibranquial (vs. alrededor de 9). Hoplias mbigua tiene perfil dorsal convexo entre cabeza y aleta dorsal y H. teres tiene perfil dorsal recto entre cabeza y aleta dorsal. Hoplias mbigua tiene supraopérculo grande, con su margen anterior en contacto con los infraorbita- les 5 y 6 mientras H. cf. malabaricus tiene supraopérculo corto, con el margen anterior apenas extendido delante del margen anterior del opérculo. Hoplias mbigua tiene placa grande con dientes, sobre basihial y basibranquiales en lugar de las dos hileras de placas dentadas en los laterales de los huesos en H. cf. malabaricus. Palabras clave: Characiformes, Hoplias, bajo Paraná.

Recibido: 06/08/15 – Aceptado: 21/09/15 72 M. Azpelicueta et al.: A new species of the genus Hoplias in Misiones (Argentina)

INTRODUCTION meristic characters indicates the holotype. Measurements and counts were taken on the The species of the characiform genus left side of body, whenever possible, follow- Hoplias (known as tarariras or taruchas in ing Mattox et al. (2006). Osteological Spanish) have a broad distribution in South names follow Oyakawa and Mattox (2009). America, being used in fisheries and sport Institutional abbreviations follow Sabaj activities in many places. Oyakawa and Mat- Pérez (2014), excluding Laboratorio de tox (2009) used morphological characters to Genética Evolutiva, Instituto de Biología define three species groups within Hoplias: Subtropical (LGE-P, IBS Conicet-UNaM), and H. lacerdae, H. malabaricus, and H. mac- Proyecto Biología Pesquera Regional (IBS rophthalmus groups. The H. lacerdae group Conicet-UNaM, named here as Anexo, pend- was defined by the absence of tooth-bearing ing collection). Information of H. microlepis plates in the fleshy tissue on the dorsal sur- was taken from Mattox et al. (2014). face of the basihyal and basibranchials and by the medial margins of contralateral den- COMPARATIVE MATERIAL taries lying almost parallel to each other. EXAMINED The group of H. malabaricus is still unde- ZMB 3515, lecto- fined but it may be recognized by the pres- , South America, probably . ence of tooth plates in the tongue (basihyal) Lectotype designated by Paepke (1999). Hop- and the medial margins of contralateral den- lias teres, MNHN 0000-4377, 2 exs., syn- taries forming an acute angle. Mattox et al. types, Lake Maracaibo, . Hoplias (2014) pointed out that the H. malabaricus mbigua: All specimens from Misiones, col- group includes at least three species: H. mal- lected by Staff of Proyecto Biología Pesquera abaricus, H. microlepis and H. teres. The Regional. Anexo 001, 2 exs., 223-254 mm third group contains a single species, H. aim- SL (standard length, snout to hypural joint), ara, characterized by the absence of an ac- río Paraná in Garupá, November 2013. An- cessory ectopterygoid and the presence of a exo 002, 4 exs., 172-310 mm SL, río Paraná dark oval spot on the opercular membrane. in Garupá, June 2014. Anexo 003, 1 ex., 45 So far, H. malabaricus is the most common mm SL, río Paraná in Nemesio Parma. An- species found in the lower Paraná River. Hop- exo 004, 2 exs., 48-54 mm SL, río Paraná in lias lacerdae (Rosso et al., 2013) and H. Nemesio Parma, April 2002. Anexo 005, 4 australis (Oyakawa and Mattox, 2009) are exs., 165-294 mm SL, río Paraná in Nemesio recorded from the lower River; the Parma, November 2003. Anexo 006, 2 exs., two species belong to the H. lacerdae group. río Paraná in Nemesio Parma, June 2002. An- The objective of this paper is the description exo 007, 2 exs., 162-230 mm SL, río Paraná of a new species of the H. malabaricus in Nemesio Parma, October 2013. Anexo group, adding morphological information. 008, 1 ex., 76 mm SL, río Paraná in Corpus, August 2009. Anexo 009, 3 exs., 234-282 MATERIAL AND METHODS mm SL, arroyo Yabebiry, May 2014. Anexo 010, 6 exs., 172-318 mm SL, arroyo Yabe- The description of the new species is biry, November 2013. FML-CI 6765, 1 ex., based on 44 specimens housed at different 280 mm SL (dried disarticulated skull), Ar- collections and hundreds of specimens mea- gentina, Provincia de Misiones, río Paraná in sured and sexed for ecological studies by the Nemesio Parma, collected with the holotype. members of the Proyecto Biología Pesquera Hoplias cf. malabaricus: MLP 4501, 1 Regional. Meristic and morphometric data ex., 101 mm SL, Argentina, Provincia de were taken in 16 specimens; all measure- Corrientes, Manantiales. MLP 5495, 3 exs., ments were taken point-to-point with digital 64-85 mm, Argentina, Paraná. MLP 6469, 1 calipers to 0.1 mm. Number of specimens is ex., 72.5 mm SL, Argentina, Provincia de presented in parentheses, the asterisk in the Formosa. MLP 7977, 3 exs., 105.4-278 mm Acta zoológica lilloana 59 (1-2): 71–82, 2015 73

SL, Argentina, Provicia de Chaco, Municipio DIAGNOSIS Resistencia, Lag. Arenosa. MLP 7995, 1 ex., The presence of tooth-bearing plates on 157.5 mm SL, Argentina, Chaco, Municipio dorsal surface of the basihyal and basibran- Resistencia, Lag. Fabril financiera. MLP chials and the medial margins of contralat- 8870, 170 mm SL, Argentina, Provincia de eral dentaries converging towards the man- Formosa, Dep. Laishi, Estancia El Bagual. dibular symphysis in ventral view, allow us MLP 8869, 1 ex., 181 mm SL, Argentina, to include the species in the H. malabaricus Provincia de Formosa, Dep. Laishi, Estancia group. The presence of five brown bands El Bagual. FML-CI 6766, 1 ex, 278 mm SL transversely placed on lower jaw distin- (dried disarticulated skull), Argentina, Pro- guishes the new species from its congeners, vincia de Misiones, río Paraná in Nemesio except H. microlepis (vs. lower jaw with Parma, collected with the holotype. small black or brown dots uniformly distrib- uted or straight). The number of circunpe- RESULTS duncular scales in H. mbigua is 20 whereas H. teres and H. malabaricus have 18 circun- Holotype.— CI-FML 6763, 224 mm SL, peduncular scales and H. microlepis 22-24, Argentina, Provincia de Misiones, río Paraná usually 24. Hoplias mbigua has convex dor- in Nemesio Parma (27° 21’ 23.04” S – 56° 1’ sal profile between head and dorsal fin and 1.92” W), Dep. Capital. November 2005, large tooth plate on basihyal whereas H. ter- coll. D. Aichino, M. Azpelicueta, D. Méndez, es has straight dorsal profile and smaller I. Rodríguez. tooth plates on basihyal. Hoplias mbigua is Paratypes.— CI-FML 6764, 2 ex., 224- distinguished from H. microlepis by the pres- 248 mm SL, collected with the holotype. ence of 12-16 gill rakers on first epibranchial LGE-P 314, 4 exs., 206.6-293 mm SL, Argen- (vs. about 9) and 42-43 lateral line scales tina, Misiones, Dep. Capital, río Paraná in (vs. 43-47). Garupá (27° 27’ 33’’ S – 55° 48’ 41’’ W), De- Hoplias mbigua has a large supraopercle, cember 13, 2013, coll. Staff of Proyecto Bi- with its anterior margin contacting the in- ología Pesquera Regional. LGE-P 315, 2 exs., fraorbitals 5 and 6 whereas the lectotype of 273-289 mm, Argentina, Misiones, río H. malabaricus has a short supraopercle, Paraná in Puerto Maní, Dep. San Ignacio with an anterior margin scarcely extended (27° 6’ 21.47” S – 55° 31’ 5.21” W), May before anterior opercular margin. Hoplias 2014, coll. Staff of Proyecto Biología mbigua is distinguished from H. cf. mala- Pesquera Regional. LGE-P 316, 2 exs., 248- baricus by the dorsal surface of head scarce- 293 mm, Argentina, Misiones, Dep. San Ig- ly or strongly concave (vs. convex in H. cf. nacio, arroyo Yabebiry (27° 17’ 39.10” S – malabaricus); a large eye, with the upper 55° 33’ 32.12” W), May 2014, coll. Staff of margin of orbit strongly marked in skull Proyecto Biología Pesquera Regional. LGE-P roof (vs. lateral margin of skull scarcely 317, 2 exs, 270-293 mm SL, Argentina, Cor- concave at orbit); the shape of anterior pro- rientes, Dep. Ituzaingó, río Paraná in Toma file of head angular in lateral view (vs. de Agua Eriday (27° 29’ 5.55” S – 56° 40’ rounded), and the lower head depth 45-50 % 33.84” W), December 2013, coll. Staff of of HL (vs. more than 50 % of HL). Hoplias Proyecto Biología Pesquera Regional. LGE-P mbigua has a large tooth-plate on basihyal 318, 2 exs., 285-281 mm SL, Argentina, Mi- and basibranchials instead of two lines of siones, Dep. Capital, arroyo Garupá, May tooth-plates at sides of bones in H. cf. mala- 2014, Staff of Proyecto Biología Pesquera baricus. We could not observe in the radio- Regional. LGE-P 319, 1 ex., 272 mm SL, Ar- graph of H. malabaricus lectotype the size or gentina, Misiones, Dep. Capital, arroyo shape of basibranchial tooth-plate. Garupá, November 2013, Staff of Proyecto Biología Pesquera Regional. 74 M. Azpelicueta et al.: A new species of the genus Hoplias in Misiones (Argentina)

DESCRIPTION profile of head straight, slanted postero-ven- Morphometric data are presented in Ta- trally; ventral profile of body slightly convex ble 1. Greatest body depth at vertical through to pelvic-fin origin; approximately straight posterior tip of pectoral fin. Body cylindri- from latter point to anal-fin origin; straight cal, deeper than wider (Fig. 1). Anterior pro- and postero-dorsally oriented along anal-fin file of head angular in lateral view, markedly base; straight or slightly concave from base angular in larger specimens. Dorsal profile of last anal-fin ray to anterior most ventral of head always concave, in some large indi- procurrent caudal-fin rays. viduals concavity more pronounced; slightly Dorsal margin of orbit at same level of convex or straight from vertical through first dorsal profile of head, eye surpassing that series of scales to dorsal-fin origin in large level in many specimens independent from specimens, straight and postero-ventrally body size. Medial margins of contralateral slanted under dorsal-fin base; slightly con- dentaries forming a V shapped angle, some- cave or straight from vertical through base times not too abrupt (Fig. 2). of last dorsal-fin ray to origin of caudal-fin Head wide, low. Upper jaw shorter than rays, independent from body size. Ventral lower jaw. Posterior tip of maxilla surpass-

Table 1. Measurements of Holotype and 15 specimens of Hoplias mbigua, new species. SL (standard length, snout to hypural joint): in mm. SD: standard de- viation. Acta zoológica lilloana 59 (1-2): 71–82, 2015 75

Fig. 1. Hoplias mbigua, holotype, lateral and ventral views. ing posterior margin of eye, more than half of terior one. Anterior and posterior nostrils orbital diameter in large specimens (more located in an oblique low slit, with its an- than 240 mm SL). Posterior portion of max- terodorsal origin at level of upper third of illa dorsally extended, covered by second orbit. Posterior nostril located very close to and third infraorbitals. Upper and lower lips eye. Eye large, strongly entering in margin fleshy with skin covering canines externally. of skull roof (Fig. 3c). Anterior nostril tubular, separated from pos-

Fig. 2. Hoplias mbigua, detail of ventral view of head with pigmented bands: a) specimen not preserved, 290 mm SL (standard length, snout to hypural joint); b) 45 mm SL; c) 68 mm SL; d) 77 mm SL. 76 M. Azpelicueta et al.: A new species of the genus Hoplias in Misiones (Argentina)

Fig. 3. Hoplias mbigua, lateral views. Different pigmentation patterns: a) opercular membra- ne completely pigmented, 293 mm SL (standard length, snout to hypural joint); b) 77 mm SL; c) specimen with 270 mm SL, very concave head and extremely large eye.

Teeth in both jaws conical or canine. quarters of its length. Also, accessory ectop- Teeth and especially large canines complete- terygoid with a line of small external conical ly covered by skin. Premaxillary teeth in a teeth and a ventral patch with viliform teeth. single row, all teeth canines but varying in Distal margins slightly rounded in all size. First premaxillary tooth large canine, fins. Dorsal-fin rays ii,12(15*), iii,12(1). followed by a second tooth medium sized Dorsal fin located nearer snout tip than cau- canine, two to four small canines, one medi- dal-fin ray origin; its origin at vertical three um-sized canine, one large canine, and two scales anterior to pelvic-fin origin. Dorsal fin or one small canines. Maxilla with single base a little more than twice length of base row, bearing three or four small canines fol- of anal fin. Longest dorsal-fin ray approxi- lowed by one medium-sized and largest one, mately 80% of body depth. Anal-fin base one medium-sized and 30 to 40 small ca- short with ii,7(1), iii,7(8), ii,8(1), iii,8(4*), nines; number of small canines increasing iii,8(1), ii,9(1) rays. Tip of adpressed dorsal during growth. fin falling near vertical through anal-fin or- Dentary with anterior external row of igin or in same line. Pectoral-fin rays with teeth and posterior internal row. External i,11(2), i,12(10), i,13(4*) rays. Pectoral-fin series with two or three small symphysial origin located at a vertical through middle canines followed by one medium-sized, and of subopercle. Tip of pectoral fin separated largest dentary canine, then several small or from pelvic-fin origin by three to four scales medium-sized canines and two larger ones. in young specimens and four to five scales in Internal series beginning immediately poste- larger ones. Pectoral and pelvic fins of simi- rior to last conical tooth of external row lar size although pelvic fin always scarcely and composed of numerous small canines longer than pectoral fin. Pelvic-fin rays (about 18). i,7(14*) or i,8(2). Pelvic-fin origin situated Ectopterygoid and accessory ectopterygoid at midbody, approximately in a vertical toothed. Ectopterygoid with one series of through third or fourth dorsal-fin ray. Tip of small conical teeth along ventral margin and pelvic fin separated from anal-fin origin by a patch of many smaller viliform teeth on ven- five or six scales. Caudal-fin rays i,15,i*. tromedial surface, occupying about three Well-developed cycloid scales, imbricated Acta zoológica lilloana 59 (1-2): 71–82, 2015 77 along entire body. Series of dorsal scales lateral line and dorsal-fin origin 6(15*), overlapping supraoccipital spine. Last verti- 5.5(1). Longitudinal series of scales between cal series of scales on caudal peduncle form- lateral line and pelvic-fin origin 5(13*) ing a relatively straight line; two or three 5.5(3). Scales around caudal peduncle last rows of scales on caudal-fin rays smaller 20(15*, one specimen with 22). than those of body. Anterior margin of scales Color upon capture. Dorsum brown, undulated, with small notch at midpoint and darker than rest of body; upper half of body posterior margin rounded. Eight to 12 radii dark brown and lower half scarcely lighter, extending from center of scale to its anterior sometimes iridescent; vent pale yellow. In margin and only two to six radii, extending many specimens (independent from body from center of scale to its posterior margin; size), a white longitudinal band extending one to three incomplete radii in lateral field from posterior opercular margin to origin of of many scales. Lateral line straight and lower caudal-fin rays, situated one scale be- complete, extending from posteroventral low perforated scales. Some specimens, with margin of supracleithrum to middle caudal- oblique brownish bands through white fin rays. Last tube of lateral line in last scale. band. Ground color of caudal fin dark, Lateral line with 42(13*), 43(3) perforated brown; remaining fins clear, brownish; all scales. Longitudinal series of scales between fins with pale yellow lines. Remarkably 5-6

Fig. 4. Supraopercle of Hoplias, snout at left: a) H. mbigua, 280 mm SL (standard length, snout to hypural joint); b) H. cf. malabaricus, 278 mm SL; c) H. malabaricus, holotype, 167 mm SL. aom: anterior opercular margin; ifo 5-6, infraorbital 5 or 6; op, opercle; S, suprao- percle. Scale bar = 5 mm. 78 M. Azpelicueta et al.: A new species of the genus Hoplias in Misiones (Argentina)

Fig. 5. Hoplias mbigua, 280 mm SL, snout at left: a) first branchial arch with toothed elon- gated and plate-like gill rakers. Scale bar = 1 cm; b) detail of plate-like gill rakers. Scale bar = 5 mm. cb, ceratobranquial; eb, epibranchial; egr, elongate gill rakers; grc, gill raker on cartilage. transverse brown bands in opercle; 6-8 opercle. Lateral and ventral surface of den- brown ventral bands from symphysis to level taries with 5-6 transverse brown bands, of posterior infraorbital margin; presence of many times also visible on maxilla. Those bands in all specimens from 45 mm SL to bands extended on angular, retroarticular, largest one 293 mm SL (Fig. 3). subopercle, interopercle, and branchiostegal Color in alcohol. Ground coloration of membranes. Brown bands present indepen- body dark to light brown, darker dorsally dent from body size (Fig. 2). Many times and paler ventrally. Ventral region light yel- opercle marbled, opercular membrane dot- low; many scales covering vent with a pale ted (Fig. 3). One small dot in dorsal half of brown dot usually located in anterior por- caudal peduncle, near caudal-fin ray origin. tion of scale, more numerous in large speci- Caudal fin dark brown, with pale yellow mens, with different shape. In most speci- bands. Dorsal, pectoral, and pelvic fins pale mens flanks with a dark longitudinal band with numerous dots forming dark bands. All along perforated line scales, covering ap- fins clear in few specimens (Fig. 3c). Bands proximately half of the series immediately on anal fin more regular than those on re- above and below lateral line; also, most maining fins. Chromatophores of pectoral specimens with a light band below dark and pelvic fins located on dorsal and ventral band. Sometimes oblique dorsoposterior dark surfaces of fins with similar pattern. stripes occupying portions of light band (Fig. 1). Dorsal surface of head dark brown, ETYMOLOGY lateral faces lighter. Sometimes, two or The name mbigua is a guaraní word that three bands radiating ventrally and posteri- refers to an aquatic, riverine bird. This word orly from eye through infraorbitals; first one is the nickname of Isabelino Rodríguez, who on infraorbital two, second band on infraor- worked during many years in the Proyecto bital three; third one, when present, on in- Biología Pesquera Regional. A noun in ap- fraorbital five, sometimes continued through position. Acta zoológica lilloana 59 (1-2): 71–82, 2015 79

DISTRIBUTION plate-like (Fig. 5). Basihyal and basibranchi- Hoplias mbigua is known from different als with a large tooth-plate, formed by many localities in the lower Paraná: arroyo Yabebi- smaller ones (Fig. 6). Laterosensory canal ry, Nemesio Parma, Corpus, Garupá, Puerto along ventral surface of dentary with four Maní in the province of Misiones and Itu- pores, two pores on articular bone (Fig. 2). zaingó in the province of Corrientes. Total vertebrae: 42 (N =3); precaudal verte- brae 28, caudal vertebrae 13 (N = 3). OSTEOLOGY Infraorbital bones well developed and REMARKS horizontally elongated. Infraorbitals 3, 4, (Rosso et al., 2013) and and ventral portion of infraorbital 5 partially H. australis (Oyakawa and Mattox, 2009) covering preopercle. Posteroventral margin are recorded from the lower Uruguay River; of infraorbitals 2 and 3 convex; posterior type material of both species is unknown. margin of infraorbitals 4 slightly convex, Other two species of the genus Hoplias were posterior margin of infraorbitals 5 and 6 described from Southern South America. Va- concave (Figs. 1, 4). lenciennes (1847) described Macrodon auri- All specimens examined with infraorbit- tus from Montevideo; it has been considered als 3 and 4 completely excluded from orbital as nomen dubium by Oyakawa and Mattox rim and infraorbital 5 contacting in great (2009). Larrañaga (1923) erected Esox extent with infraorbital 2. In small speci- tararira, subsequently treated as H. mala- mens (45 to 100 mm SL), infraorbital 3 baricus by Devincenzi (1925). The brief in- completely excluded from orbital margin complete description of the nominal species although infraorbital 4 is located nearer provides little information in identifying the orbital margin. species and only indicates that it is a mem- Supaopercle large, its anterior half con- ber of the genus Hoplias. tacting posterodorsal margin of infraorbital The H. malabaricus species group defined 5 and posterior margin of infraorbital 6 by Oyakawa and Mattox (2009) contains all (Fig. 4a). species with dentaries abruptly converging Twelve to 14 gill rakers on first epibran- towards the mandibular symphysis and with chial, two of them elongated laminae near bony tooth-plates on basihyal and basibran- cartilage between ceratobranchial and epi- chials. The possession of basihyal tooth branchial; remaining gill rakers with form plates is broadly distributed in Characi- of small denticulated plates, one laminar gill formes (Zanata and Vari, 2005). During this raker on cartilage (Fig. 5). First ceratobran- study, we found two different arrangements chial with 15-18 gill rakers, only four or five of bony tooth-plates on basihyal and basi- laminar and elongate; remaining gill rakers branchials. Hoplias mbigua has a large plate

Fig. 6. Hoplias mbigua, detail of tooth-plates on basihyal and basibranquials, snout at left: a) Hoplias mbigua, 280 mm SL (standard length, snout to hypural joint); b) H. cf. malabaricus, 278 mm SL. 80 M. Azpelicueta et al.: A new species of the genus Hoplias in Misiones (Argentina)

Fig. 7. Detail of the laminar expansion in the neural spine of vertebra 5; snout at left: a) schematic drawing (taken from a radiograph) of Hoplias mbigua, 124 mm SL (standard leng- th, snout to hypural joint); b) radiograph of H. malabaricus, lectotype, 167 mm SL. Scale bar = 1 mm; e, expansion of neural spine 5; nav4, neural arch of vertebra 4. formed by smaller ones, located medially canal system. At present, in the literature, and some plates at sides of basibranchials both bones appear with different names, the (Fig. 6a). Hoplias cf. malabaricus has two laminar supraopercle in Erythrinidae and lateral rows of small plates, clearly separat- Hepsetidae, above the opercle and without a ed (Fig. 6b). canal, and the tubular suprapreopercle, as The Erythrinidae has a laminar suprao- dorsal expansion of the preopercular canal percle (Roberts, 1969, page 446, Fig. 3). (Mirande pers. com.). Two different types of Zanata and Vari (2005) discussed an uncer- laminar supraopercle are present in the spe- tain homology of this bone with the sensory cies examined. Hoplias mbigua has a large canal segment located above suprapreoper- supraopercle; the anterior third of the bone cle of other Characiformes because the lam- is anterior to the opercular margin (Fig. 4a). inar bone of Hoplias does not have a sensory Hoplias cf. malabaricus has a short suprao- Acta zoológica lilloana 59 (1-2): 71–82, 2015 81

percle, with its anterior margin approxi- LITERATURE CITED mately in the same vertical than anterior opercular margin (Fig. 4b); the lectotype of Bertollo L., Fontes M., Fenocchio A., Cano, J. 1997. H. malabaricus has this condition (Fig. 4c). The X1X2Y sex chromosome system in the Hoplias malabaricus. I. G-, C-and chromosome In the radiograph of the lectotype of H. replication banding. Chromosome research, 5: malabaricus there is a curious laminar ex- 493-499. pansion in the neural spine of vertebra 5 Bertollo L., Born G., Dergam J., Fenocchio A., Morei- (Fig. 7b). All specimens examined of H. ra-Filho A. 2000. A biodiversity approach in the mbigua (Fig. 7a) and H. cf. malabaricus neotropical Erythrinidae fish, Hoplias malabari- cus. Karyotypic survey geographic distribution of have the same structure that is not common cytotypes and cytotaxonomic considerations. in characiforms. Future studies of Hoplias Chromosome Research, 8: 603–613. will indicate the presence of this character in Da Rosa R., Vicari M., Dias A., Giuliano-Caetano L. different species of the genus, trying to estab- 2014. New Insights into the Biogeographic and lish the phylogenetic value of the character. Karyotypic Evolution of Hoplias malabaricus. Zebrafish, 11: 198-206. Differences on karyotype structure, dip- Devincenzi, G. 1925. El primer ensayo sobre Ictyiolo- loid number, chromosome banding and even gía del Uruguay. La clase «Peces» de la zoología sexual chromosome systems were reported de don Dámaso A. Larrañaga. Anales del Museo in H. malabaricus by several authors (Bertol- Nacional de Historia Natural de Montevideo (Se- lo et al., 1997; Lopes et al., 1998; Bertollo rie 2), v. 6: 295-323. Ferreira Marques D., Santos F., Silva S., Sampaio I., et al., 2000; Pazza & Ferreira Julio, 2003; Rodrigues L. 2013. Cytogenetic and DNA barco- Ferreira Marques et al., 2013; da Rosa et ding reveals high divergence within the trahira, al., 2014). The main framework to cytoge- Hoplias malabaricus (Characiformes: Erythrinidae) netic comparison have been proposed by Ber- from the lower Amazon River. Neotropical Ichth- tollo et al. (2000) who described 7 cytotypes yology, 11 (2): 459-466. Larrañaga, D. 1923. Escritos de Don Dámaso Antonio (denominated A-G), some of them even Larrañaga. Instituto Histórico y Geográfico del found in syntopy and without intermediate Uruguay, Edición Nacional, 2: 1-512. hybrids, which reinforce the hypothesis of H. Lopes P., Alberdi A., Dergam J., Fenocchio A. 1998. malabaricus as a species complex. Méndez Cytotaxonomy of Hoplias malabaricus (Ostei- (2007), working on specimens of H. cf. mal- chthyes, Erythrinidae) in the Aguapey River (Pro- vince of Corrientes, Argentina). Copeia, 1998 (3): abaricus and H. mbigua from the Paraná Riv- 485-487. er in Misiones, Argentina, found two differ- Mattox G., Bifi A., Oyakawa O. 2014. Taxonomic study ent cytotypes which also had morphological of (Gunther, 1864), a trans- differences between them. Based on his study, Andean species of trahiras (Ostariophysi: Chara- the species here described would present cy- ciformes: Erythrinidae). Neotropical Ichthyology, 12 (2): 343-352. totype «C» of Bertollo et al. (2000) with Mattox G., Toledo-Pizza M., Oyakawa O. 2006. Taxono- 2n=40, metacentric and submetacentric mic study of (Valenciennes, 1846) chromosomes and no differences between and Hoplias macrophthalmus (Pellegrin, 1907) sexes. (Ostariophysi: Characiformes: Erythrinidae). Co- peia, 2006 (3): 516-528. Méndez C. 2007. Caracterización cariotípica y morfo- ACKNOWLEDGMENTS lógica de poblaciones de Hoplias malabaricus (Characiformes, Erythrinidae) residentes aguas Authors thank P. Bartsch (ZMB) for pho- arriba de la represa Yacyretá. Tesis de Licencia- tographs and radiograph of the lectotype of tura en Genética, Facultad de Ciencias Exactas, H. malabaricus and J. M. Díaz de Astarloa Químicas y Naturales, Universidad Nacional de (Conicet-UNMdP) for photographs and infor- Misiones, Argentina, 53 pp. Oyakawa O., Mattox G. 2009. Revision of the Neotro- mation of syntypes of H. teres; all members pical trahiras of the Hoplias lacerdae species- of Proyecto Biología Pesquera Regional for group (Ostariophysi: Characiformes: Erythrinidae) all captured specimens; M. Mirande and an with descriptions of two new species. Neotropi- unknown referee for suggestions and correc- cal Ichthyology, 7 (2): 117-140. tions. Paepke H.-J. 1999. Bloch’s fish collection in the Museum für Naturkunde der Humboldt Universi- 82 M. Azpelicueta et al.: A new species of the genus Hoplias in Misiones (Argentina)

tät zu Berlin: an illustrated catalog and historical Sabaj Pérez M. (editor). 2014. Standard symbolic account. Ruggell (Liechtenstein). Theses Zoolo- codes for institutional resource collections in gica, 32: 1-216. herpetology and ichthyology: an Online Reference. Pazza R., Ferreira Júlio H. 2003. Occurrence of Three Version 5.0 (22 September 2014). Electronically Sympatric Cytotypes of Hoplias malabaricus (Pis- accessible at http://www.asih.org/, American ces, Erythrinidae) in the Upper Paraná River Society of Ichthyologists and Herpetologists, Floodplain. Cytologia, 68: 159-163. Washington, DC. Roberts, T. 1969. Osteology and relationships of cha- Valenciennes A. 1847. (In Cuvier and Valenciennes racoid , particularly the genera Hepsetus, 1847). Histoire naturelle des poissons. Tome dix- Salminus, Hoplias, Ctenolucius and Acestrorhyn- neuvième. Suite du livre dix-neuvième. Brochets chus. Proceedings of the California Academy of ou Lucioïdes. Livre vingtième. De quelques fami- Sciences, 36: 391-500. lles de Malacoptérygiens, intermédiaires entre Rosso J., Mabragaña E., Schenone N., Avigliano E., les Brochets et les Clupes. P. Bertrand, Paris, González Castro M., Díaz De Astarloa J. 2013. 19: 1-590. El género Hoplias en Argentina: expandiendo Zanata A., Vari R. 2005. The family Alestidae (Osta- registros y una nueva especie. Resúmenes del riophysis, Characiformes): a phylogenetic analy- 3º Simposio Argentino de Ictiología, pag. 57. sis of a trans-Atlantic clade. Zoological Journal of the Linnean Society, 145: 1-144.