A New Species of Gymnotus (Gymnotiformes: Gymnotidae) from Rio Tiquié in Northern Brazil

Abstract

Gymnotus tiquie, new species, is described from the Rio Tiquié , a tributary of the Uaupé s (Vaupé s) in the upper Negro basin, Amazonas, Brazil. The new species was collected in non-floodplain (terra firme) streams, where it occurs sympatrically and syntopically with two geographically widespread congeners, the type species of the genus, G. carapo, and G. coropinae. The new species is diagnosed by a unique combination of morphometric, meristic, and osteological traits, and by a characteristic color pattern in which the dark oblique pigment bands, diverse in shape and design, are divided into band-pairs along the length of the body, in which the band-pairs are often recurved (dorsally concave), more variable, and often reticulated in the abdominal region, and in which the pale inter-bands meet at the dorsal midline along most of the length of the body. Gymnotus tiquie is a member of the G. pantherinus species group, with which it shares the presence of one (vs. two) pore in the dorsolateral portion of the preopercle (except in G. pantanal and G. anguillaris), needle-shaped (vs. conical or arrowhead-shaped) teeth on the dentary and premaxilla, and a slender body (BD 5.6-10.6% HL vs. deep 8.7-13.5%, except G. chaviro, G. curupira, G. varzea, G. chimarrao, G. maculosus, G. henni, and G. inaequilabiatus that also have a slender body). Gymnotus tiquie is most similar in overall appearance to G. cataniapo of the upper Orinoco. These two species share three unique features within the G. pantherinus group: dark band-pairs with wavy irregular margins along the length of the body, a long body cavity with 45 or more pre-caudal vertebrae, and a darkly pigmented membrane in the caudal region of the anal fin.Gymnotus tiquie, nova espécie, é descrita para o rio Tiquié, um afluente do rio Uaupés (Vaupés), bacia do alto rio Negro, Amazonas, Brasil. A nova espécie foi coletada em igarapé s de terra firme, onde ela ocorre simpatricamente e sintopicamente com dois congêneres geograficamente amplamente distribuídos, a espécie-tipo do gênero, G. carapo, e G. coropinae. A nova espécie é diagnosticada por uma combinação ú nica de caracteres morfométricos, meristicos e osteoló gicos, e por um padrão de colorido característico no qual as faixas oblíquas escuras, variadas em forma, são divididas em pares de bandas ao longo do corpo, nos quais os pares de bandas são frequentemente recurvados (côncavos dorsalmente), mais variá veis, e frequentemente reticulados na região abdominal, e nos quais as faixas intermediárias pá lidas encontram-se na região dorsal média ao longo da maior parte do comprimento do corpo. Gymnotus tiquie é um membro do grupo de espécies G. pantherinus, com o qual compartilha a presença de um (vs. dois) poros na porção dorsolateral do pré-opérculo, dentes do dentário e pré-maxila em forma de agulha (vs. dentes do dentário e pré-maxila cônicos ou em forma de ponta de flecha) e um corpo alongado (altura do corpo 5.6-10.

Gymnotus capanema, a new species of electric knife fish (Gymnotiformes, Gymnotidae) from eastern Amazonia, with comments on an unusual karyotype

“…They are recognized by a prognathous lower jaw, oblique bands along the body (Albert et al , 2004) and by the generation of pulsed weakly electric organ discharges (EOD) for locating objects in the dark, and for communication (Caputi, 1999; Crampton & Albert, 2006; Rodriguez‐Cattaneo et al , 2008). Gymnotus has been the focus of intense taxonomic effort in recent years, and the number of described species increased from nine in 1994 (Mago‐Leccia, 1994) to 36 in 2011 (Albert & Crampton, 2003; Crampton et al , 2003, 2005; Maldonado‐Ocampo & Albert, 2004; Fernandes et al , 2005; Cognato et al , 2007; Maxime & Albert, 2009; Richer‐de‐Forges et al , 2009; Maxime et al , 2011) (see Table I). Albert et al (2004) provided a species‐level phylogeny for the genus based on morphological and osteological characters and recognized three species groups within the genus: the Gymnotus cylindricus La Monte 1935, Gymnotus pantherinus (Steindachner 1908) and Gymnotus carapo L. 1758 species groups (Table I).…”

“…comm.). Some eight species of Gymnotus are known from the Rio Negro basin in the Brazilian Amazon (although only one, Gymnotus tiquie Maxime, Albert & Lima 2011, was described from this basin): G. arapaima, G. coropinae, G. carapo, Gymnotus cataniapo Mago‐Leccia 1994, Gymnotus pedanopterus Mago‐Leccia 1994, Gymnotus stenoleucus Mago‐Leccia 1994 and G. tiquie . Even lower levels of diversity are known from the lower Amazon, east of the confluence of the Rio Negro and Amazon at Manaus, but excluding the Madeira system.…”

Gymnotus interruptus, a new species of electric fish from the Rio de Contas basin, Bahia, Brazil (Teleostei: Gymnotiformes: Gymnotidae)

“…Drawings were made with a camera lucida connected to a stereoscopic microscope. Morphometric measurements follow mago- LeCCia (1978) and Campos-da-paz (2002). The term "postorbital" is used instead of "postocular".…”

“…To make possible the construction of the diagnosis through the comparison of obtained data with the data available in literature (e.g. original descriptions of valid species and reference papers as aLbert & Crampton, 2003a) the measurements reported as head length (HL) percentage were also reported as snout-to-opercle length percentage (equivalent to head length of some authors, e.g., aLbert & Crampton, 2003a;maxime et al, 2011), making the data comparable to most data present in the literature. Meristic data were taken following the procedures given by aLbert & Crampton (2003a), except for the number of precaudal vertebrae, which follows Campos-da-paz (2002).…”