Osteoglossum bicirrhosum (Cuvier, 1829) DNA Diagnosis. This species can be distinguished from O. ferreirai by combinations of the following nucleotide characters: COII region: 528T, 561C, 567C, 582A, 585G, 603C, 606C, 612T, 618C, 648G. Lysine tRNA region: 22T, 41C, 45G. ATP8 region:6A, 12C, 15T, 27G, 30A, 33G, 37T, 54G, 72C, 84C; 112A.ATP6 region: 87C, 96C, 111C, 114C, 138A, 150T, 192G, 198C, 213T, 217T, 219T, 226G, 249C, 258G, 265T, 267A, 282C, 285A, 294G, 300G, 312G, 313T, 318G, 324A, 330G, 333C, 339T, 351T, 363A, 393T, 394G, 410C, 429C, 447C, 448C, 450C, 474G, 489T, 495C, 508T, 528C, 552T, 576G, 583A, 585T, 586T, 591T, 600A, 607C, 625G, 627T, 633A, 654G, 657A. Morphological features (data from Kanazawa, 1966). Tip of snout to anus 45.5 to 53.2; snout to origin of dorsal fin 55.9 to 61.9; snout length 3.7 to 6.5; eye diameter 3.1 to 8.7; head length 19.6 to 26.9; body depth 14.6 to 20.7. These data are given in percentages with respect to standard length. Branched dorsal fin rays 42 to 50; unbranched anal fin rays 49 to 58; pectoral rays i, 6; scales along the lateral line to base of caudal fin 30 to 37; pre-dorsal scales 16 to 19. Adult color is varied and can be silver, yellow, or dark greenish, paler ventrally. Distribution. Essequibo River basin; Amazon River basin not including the Negro River basin except its Branco River affluent.

Published as part of L, María Doris Escobar, Farias, Izeni P., Taphorn B, Donald C., Landines, Miguel & Hrbek, Tomas, 2013, Molecular diagnosis of the arowanas Osteoglossum ferreirai Kanazawa, 1966 and O. bicirrhossum (Cuvier, 1829) from the Orinoco and Amazon River basins, pp. 335-340 in Neotropical Ichthyology 11 (2) on page 337, DOI: 10.1590/S1679-62252013000200011, http://zenodo.org/record/12652382