Abstract
ABSTRACT Catfishes of the family Astroblepidae form a group composed by 82 valid species of the genus Astroblepus 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 Little has been advanced in the systematics and biodiversity of astroblepids other than an unpublished thesis, a single regional multilocus study and isolated species descriptions.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 cis-Andean 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.
Highlights
The family Astroblepidae includes 82 valid species within the single genus Astroblepus Humboldt, 1805 (Fricke et al, 2020) characterized by a specialized head and body morphology, with the presence of a sucker-shaped mouth with fleshy and expanded lips and a dorsal opening to the gill chamber, between the dorsal margin of the opercle and the ventral edge of the pterotic (Schaefer, 2003)
Fourteen clusters were coincident among all methods, nine were coincident only between Automatic Barcode Gap Discovery (ABGD) and PTP, 13 between ABGD and Generalized Mixed Yule-Coalescent model (GMYC) and two clusters between bPTP and GMYC (Fig. 3)
In the Northern Andes Clade, the Bayesian Phylogenetics and Phylogeography (BP&P) analysis supported 11 lineages from multiple trans and cis-Andean rivers, involving Orinoco, Amazon, and Magdalena-Cauca basins and Pacific coastal drainages of Colombia and Ecuador. These results indicated poor support values for the delimitation of A. itae Ardila-Rodriguez, 2011, A. micrescens, A. onzagaensis Ardila-Rodriguez, 2015, A. latidens Eigenmann, 1918, A. aff. trifasciatus, FIGURE 4 | Species tree inferred from the concatenated dataset of mitochondrial genes (COI, cytochrome b (Cytb), and 16S)
Summary
The family Astroblepidae includes 82 valid species within the single genus Astroblepus Humboldt, 1805 (Fricke et al, 2020) characterized by a specialized head and body morphology, with the presence of a sucker-shaped mouth with fleshy and expanded lips and a dorsal opening to the gill chamber, between the dorsal margin of the opercle and the ventral edge of the pterotic (Schaefer, 2003) Species of this genus have bodies without bony plates and with a modified pelvic musculature completely separate from the hypaxial muscles, forming a pair of strings-like muscles between the pectoral and pelvic fins (the protractor ischii muscles; Shelden, 1937). Distribution and ecological niche modeling analyses have demonstrated that astroblepids are physiologically confined to drainage islands in the Andes, where elevation and temperature oscillation strongly influence their geographical ni.bio.br | scielo.br/ni
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