The Fitzcarrald Arch: A Vicariant Event for Chaetostoma (Siluriformes: Loricariidae) Speciation?

Abstract

The genus Chaetostoma is a species-rich group of armored catfishes that inhabits rivers and streams in montane forests of South America. Most species of Chaetostoma have been described based on only one or a few specimens from a single river system. Our aim was to determine if the lifting of the Fitzcarrald Arch, 4 Ma, triggered speciation between the disjunct populations of Chaetostoma lineopunctatum in two isolated river drainages: the Río Ucayali and the Río Madre de Dios. We addressed this question by quantifying morphological and molecular divergence among samples of C. lineopunctatum from four river systems, three of which drain into the Río Ucayali drainage, including the type locality for the species, and one river system which drains into the Río Madre de Dios drainage. Morphological divergence, based on measurements, was statistically significant in the MANOVAs for the samples grouped by locality (P , 0.025) and by river system (P , 0.025). However, neighbor-joining trees of specimens grouped by locality (based on Mahalanobis distances) did not show group patterns according to river system. Morphologically, the specimens can be discriminated by river system with up to 88.7% confidence based on size-free discriminant analysis. Furthermore, the divergence values among haplotypes from the Río Ucayali and the Río Madre de Dios drainages, based on partial cytochrome b sequences (801 bp), ranged from 1.1% to 1.5%, which overlaps the 1.2% divergence between haplotypes from the Río Ucayali drainage. Based on the available morphological and molecular data, we conclude that there are not significant differences among populations of C. lineopunctatum from the Río Ucayali and the Río Madre de Dios drainages, and thus the Fitzcarrald Arch uplift did not cause speciation in this taxon. Alternatively, we suggest that isochronous tectonic events prior to the uplift of the Fitzcarrald Arch could have triggered genetic isolation of populations of C. lineopunctatum.

A history of the biogeography of Amazonian fishes

“…Lundberg et al (1998) triggers a flood of papers following similar lines (e.g. Albert et al, 2006;Hubert, Renno, 2006;Lovejoy et al, 2006Lovejoy et al, , 2010Hubert et al, 2007;Sabaj et al, 2007;Bloom, Lovejoy, 2011;Salcedo et al, 2011;Schaefer, 2011;Winemiller, Willis, 2011;Mariguela et al, 2013;Ribeiro et al, 2013;Slobodian, Bockmann, 2013;Ivanyisky, Albert, 2014;Roxo et al, 2014;Silva et al, 2014;Ribeiro, Menezes, 2015 and many others). Most of those contributions focus on specific biogeographical patterns and some introduce analytical approaches in their analyses (e.g.…”

Description of <i>Loraxichthys lexa</i>, new genus and species (Siluriformes: Loricariidae) from the Río Huallaga Basin, central Peru, with notes on the morphology of the enigmatic <i>Lipopterichthys carrioni</i> Norman, 1935

“…Counts and measurements follow the methods outlined by Salcedo (2006Salcedo ( , 2011, with fin-ray counts taken from whole specimens preserved in ethanol. Cleared and counterstained (CS) specimens were prepared following Taylor & Van Dyke (1985).…”

A new species of Chaetostoma (Siluriformes: Loricariidae) from the Orinoco basin with comments on Amazonian species of the genus in Colombia

“…This genus is one of the most species‐rich of the subfamily Hypostominae along with Hypostomus and Ancistrus , and is in need of taxonomic review with several species of uncertain validity, and a number of undescribed species. Although there have been different works dealing with the taxonomy of Peruvian and Ecuadorian species of Chaetostoma (Lujan et al ., 2015a, 2015c; Salcedo, 2006, 2013; Salcedo et al ., 2011; Salcedo & Ortega, 2015), the status of Colombian and especially Venezuelan species is comparatively poorer, despite modest efforts in the past (Ballen, 2011; Ballen et al ., 2016). Currently 23 species have been documented in Colombia, which represents about half the known diversity in the genus.…”