Abstract
Characidium tapuia, a new species apparently endemic to the rio Parnaíba basin, Brazil, is described. The new species is easily distinguished from congeners, except C. lanei, C. nana, and C. samurai, by having a broad and conspicuous dark lateral stripe, extending from the tip of snout to the end of caudal peduncle and by the absence of dark vertical bars on body of specimens larger than 23.0 mm SL. Characidium tapuia differs from the aforementioned species by a series of features, including 12 circumpeduncular scales (vs. 13 or 14 in C. lanei and C. samurai), presence of parietal branch of the supraorbital canal (vs. absence in C. lanei and C. nana), complete lateral line and adipose fin present (vs. lateral line incomplete and adipose fin absent in C. nana), and midlateral stripe with irregular borders (vs. lateral stripe with overall straight borders in C. samurai).
References
Buckup, P.A. (1993a) Review of the characidiin fishes (Teleostei: Characiformes), with descriptions of four new genera and ten new species. Ichthyological Exploration of Freshwaters, 4, 97–154.
Buckup, P.A. (1993b) Phylogenetic interrelationships and reductive evolution in Neotropical characidiin fishes (Characiformes: Ostariophysi). Cladistics, 9 (3), 305–341.
https://doi.org/10.1111/j.1096-0031.1993.tb00227.xBuckup, P.A. & Reis, R.E. (1997) Characidiin genus Characidium (Teleostei, Characiformes) in southern Brazil, with description of three new species. Copeia, 3, 531–548.
https://doi.org/10.2307/1447557Buckup, P.A. & Hahn, L. (2000) Characidium vestigipinne: a new species of Characidiinae (Teleostei, Characiformes) from Southern Brazil. Copeia, 2000 (1), 150–155.
https://doi.org/10.1643/0045-8511(2000)2000[0150:cvanso]2.0.co;2Buckup, P.A., Zamprogno, C., Vieira, F. & Teixeira, R.L. (2000) Waterfall climbing in Characidium (Crenuchidae, Characidiinae) from eastern Brazil. Ichthyological Exploration of Freshwaters, 11 (3), 273–27.
Eschmeyer, W.N., Fricke, R. & van der Laan, R. (Eds.) (2018) Catalog of fishes: Genera, Species, References. Avaliable from: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (accessed 26 February 2018)
Fricke, R. & Eschmeyer, W.N. (2017) A guide to fish collections in the Catalog of Fishes. Available from: http://researcharchive.calacademy.org/research/Ichthyology/catalog/collections.asp (accessed 17 July 2017)
Graça, W.J. & Pavanelli, C.S. (2008) Characidium heirmostigmata, a new characidiin fish (Characiformes: Crenuchidae) from the upper rio Paraná basin, Brazil. Neotropical Ichthyology, 6, 53–56.
https://doi.org/10.1590/S1679-62252008000100006International Union for Conservation of Nature (IUCN) (2018) IUCN Red List Categories and Criteria (Version 3.1, Second edition). Available from: http://www.iucnredlist.org/technical-documents/categories-and-criteria (accessed 6 November 2018)
Melo, M. & Oyakawa, O.T. (2015) A new species of Characidium Reinhardt (Characiformes, Crenuchidae) with a distinctively dimorphic male. Copeia, 103 (2), 281–289.
https://doi.org/10.1643/CI-14-073Melo, F.A.G., Buckup, P.A., Ramos, T.P.A., Souza, A.K.N., Silva, C.M.A., Costa, T.C., Ribeiro, A.T. (2017) Fish Fauna of the lower course of the Parnaíba river, northeastern Brazil. Boletim do Museu de Biologia Melo Leitão, 38 (4), 363–400.
Mendonça, M.B. & Netto-Ferreira, A.L. (2015) New species of Characidium (Characiformes: Crenuchidae) from the Rio Tapajós and Rio Xingu drainages, Pará, Brazil. Zootaxa, 4021 (1), 187–194.
https://doi.org/10.11646/zootaxa.4021.1.9Netto-Ferreira, A.L., Birindelli, J.L.O. & Buckup, P.A. (2013) A new miniature species of Characidium Reinhardt (Ostariophysi: Characiformes: Crenuchidae) from the headwaters of the rio Araguaia, Brazil. Zootaxa, 3664 (3), 361–368.
https://doi.org/10.11646/zootaxa.3664.3.6Ramos, T.P.A., Ramos, R.T.C. & Ramos, S.Q.A. (2014) Ichthyofauna of the Parnaíba River basin, northeastern Brazil. Biota Neotropica, 14 (1), 1–8.
https://doi.org/10.1590/S1676-06020140039Silva, M.J., Costa, B.G., Ramos, T.P.A., Auricchio, P. & Lima, S.M.Q. (2015) Ichthyofauna of the Gurgueia River, Parnaíba River basin, northeastern Brazil. Check List, 11 (5), 1765.
https://doi.org/10.15560/11.5.1765Sobrinho, B.L. (1946) O devassamento do Piauí. Companhia Editora Nacional, São Paulo, 190 pp.
Taylor, W.R. & Van Dyke, G.C. (1985) Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study. Cybium, 9, 107–109.
Travassos, H. (1967) Três novas espécies do gênero Characidium Reinhardt, 1866 (Actinopterygii, Characoidei). Papéis Avulsos de Zoologia, 20 (4), 45–53.
Zanata, A.M. & Camelier, P. (2014) A new species of Characidium (Characiformes: Crenuchidae) from small coastal drainages in northeastern Brazil, with remarks on the pseudotympanum of some species of the genus. Neotropical Ichthyology, 12 (2), 333–342.
https://doi.org/10.1590/1982-0224-20130168Zanata, A.M. & Ohara, W.M. (2015) A new species of Characidium Reinhardt (Ostariophysi: Characiformes: Crenuchidae) from headwaters of rio Pacaás Novos, rio Madeira basin, Rondônia, Brazil. Zootaxa, 4021 (2), 368–376.
https://doi.org/10.11646/zootaxa.4021.2.7