Molecular diagnosis of the arowanas Osteoglossum ferreirai Kanazawa, 1966 and O. bicirrhossum (Cuvier, 1829) from the Orinoco and Amazon River basins Author L, María Doris Escobar Laboratório de Evolução e Genética Animal, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, AM, Brazil. tomas @ evoamazon. net (TH) Brazil.tomas@evoamazon.net Author Farias, Izeni P. Laboratório de Evolução e Genética Animal, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, AM, Brazil. tomas @ evoamazon. net (TH) Brazil.tomas@evoamazon.net Author Taphorn B, Donald C. Aquatic Experts, 1822 North Charles Street, Belleville, IL, 62221, USA. Author Landines, Miguel Laboratorio de Fisiología de Peces, Universidad Nacional de Colombia, Bogotá, Colombia. Author Hrbek, Tomas Laboratório de Evolução e Genética Animal, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, AM, Brazil. tomas @ evoamazon. net (TH) Brazil.tomas@evoamazon.net text Neotropical Ichthyology 2013 2013-06-28 11 2 335 340 http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252013000200335&lng=en&tlng=en journal article 299538 10.1590/S1679-62252013000200011 604257df-914c-4734-9cda-76be21cf095a 1982-0224 12652382 Osteoglossum ferreirai Kanazawa, 1966 DNA Diagnosis. This species can be distinguished from O. bicirrhosum combinations of the following nucleotide characters: COII region: 528C, 561T, 567T, 582G, 585A, 603T, 606T, 612C, 618T, 648A. Lysine tRNA region: 22C, 41T, 45A. ATP8 region: 6G, 12T, 15C, 27A, 30G, 33A, 37C, 54A, 72T, 84T, 112G. ATP6 region: 87T, 96C, 111T, 114T, 138G, 150C, 192A, 198T, 213C, 217C, 219A, 226A, 249T, 258A, 265C, 267G, 282T, 285C, 294A, 300A, 312A, 313C, 318A, 324C, 330A, 333T, 339C, 351G, 363G, 393A, 394A, 410T, 429T, 447T, 448T, 450A, 474T, 489C, 495T, 508C, 528T, 552C, 576A, 583G, 585C, 586C, 591C, 600G, 607T, 625A, 627C, 633G, 654A, 657G. Morphological features (data from Kanazawa, 1966 ). Tip of snout to anus 48.5; snout to origin of dorsal fin 53.6; snout length 6.4; eye diameter 7.0; head length 22.6; body depth 13.9. These data are given in percentages with respect to standard length. Branched dorsal fin rays 52 to 57; unbranched anal fin rays 61 to 66; pectoral rays i, 6; scales along the lateral line to base of caudal fin 37 to 40; pre-dorsal scales 15 to 19. Adult color is dark bluish, paler ventrally. Fig. 2. Maximum likelihood phylogenetic hypothesis of relationships of Osteoglossum individuals representing the species O. bicirrhossum and O. ferreirai . Distribution: Negro River basin, including the affluent Branco River; Orinoco River basin.