Acta zoológica lilloana 59 (1-2): 71–82, 2015 71 A new species of the genus Hoplias (Characiformes, Erythrinidae), a tararira from the lower Paraná River, in Misiones, Argentina 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- Hoplias malabaricus ZMB 3515, lecto- fined but it may be recognized by the pres- type, South America, probably Suriname. 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, Venezuela. 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 Uruguay 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.