Ochoa LE, Melo BF, García-Melo JE, Maldonado-Ocampo JA, Souza CS, Albornoz-Garzón JG, Conde-Saldaña CC, Villa-Navarro F, Ortega-Lara A, Oliveira C. Species delimitation reveals an underestimated diversity of Andean catfishes of the family Astroblepidae (Teleostei: Siluriformes). Neotrop Ichthyol. 2020; 18(4):e200048. https://doi.org/10.1590/1982-0224-2020-0048
inhabiting high-gradient streams and rivers throughout tropical portions of the Andean Cordillera. Little has been advanced in the systematics and biodiversity of astroblepids other than an unpublished thesis, a single regional multilocus study and isolated species descriptions. Here, we examined 208 specimens of Astroblepus that apparently belong to 16 valid species from several piedmont rivers from northern Colombia to southern Peru. Using three single-locus approaches for species delimitation in combination with a species tree analysis estimated from three mitochondrial genes, we identified a total of 25 well-delimited lineages including eight valid and 17 potential undescribed species distributed in two monophyletic groups: the Central Andes Clade, which contains 14 lineages from piedmont rivers of the Peruvian Amazon, and the Northern Andes Clade with 11 lineages from trans- and cisAndean rivers of Colombia and Ecuador, including the Orinoco, Amazon, and Magdalena-Cauca basins and Pacific coastal drainages. Results of species delimitation methods highlight several taxonomical incongruences in recently described species denoting potential synonymies.
FIGURE 1 | Species of Astroblepus included in this study, A. A. ardiladuartei (LBP 26696 topotype live, 4.54 mm SL), B. A. cachara (LBP 26712 topotype live, 4.23 mm SL), C. A. caquetae (CZUT-IC 18464 topotype of museum, 7.84 mm SL), D. A. curitiensis (LBP 97118 topotype live, 5.92 mm SL), E. A. homodon (CZUT-IC 18390, 6.15 mm SL), F. A. gr. grixalvii (LBP24242 topotype live, 11.70 mm SL); F’. A. gr. grixalvii (CZUT-IC 18498 specimen of Magdalena basin 6,01 mm SL); F”. A. gr. grixalvii (CZUT-IC 18320 specimen of Cauca basin, 15.25 mm SL), G. A. itae (topotype live, 3.58 mm SL), H. A. latidens (topotype live, 13.40 mm SL), I. A. onzagaensis (topotype live, 7.82 mm SL), J. A. pradai (topotype live, 4.53 mm SL), K. A. trifasciatus (topotype of museum, 9.65 mm SL), K’. A. trifasciatus (topotype of museum, 9.01 mm SL), L. A. aff. trifasciatus (specimen of Magdalena basin, 7.94 mm SL), M. A. verai (topotype live, 3.51 mm SL).
FIGURE 2 | Map of northwestern South America showing the geographic distribution of samples used in this study and species distribution of Astroblepus reported in Global Biodiversity Information Facility (GBIF) and the California Academy of Sciences (CAS) databases.
FIGURE 3 | Results of single-locus approaches using cytochrome oxidase c subunit I (COI) for developing preliminary species delimitation hypothesis with 42 lineages. Results are represented on the ultrametric gene tree with collapsed nodes. All nodal support values were PP>0.95. Blocks at right of the tree represent hypothesized species groups and the values in the middle indicate the number of clusters identified by ABGD, bPTP and GMYC analyses for every collapsed node. COL: Colombia, ECU: Ecuador, PER: Peru.
FIGURE 4 | Species tree inferred from the concatenated dataset of mitochondrial genes (COI, Cytb, and 16S). Nodal support values are Bayesian posterior probabilities. Non-significant speciation probabilities identified in BP&P analysis algorithm A10 (PP:<0.95) are indicate by black circles and species supported with asterisk.
