The genus Basilichthys (Teleostei: Atherinopsidae) revisited along its Chilean distribution range (21° to 40° S) using variation in morphologyand mtDNA

Abstract

The genus Basilichthys (Teleostei: Atherinopsidae) revisited along its Chilean distribution range (21º to 40º S) using variation in morphology and mtDNAEl género Basilichthys (Teleostei: Atherinopsidae) analizado a lo largo de su distribución en Chile (21º a 40º S), utilizando rasgos morfológicos y variabilidad del ADN mitocondrial ABSTRACTThere is still doubt as to the number of species of the freshwater Chilean ichthyofauna, 64 % of which have conservation problems. One of the groups is that of the silversides of the genus Basilichthys. Three morphological species of this genus have been described in Chile with disjoint distributions: Basilichthys semotilus, B. microlepidotus and B. australis; the latter two overlap in distribution only in the Aconcagua River and are not easily distinguishable by morphological and meristic characters. In order to evaluate the effi cacy of identifi cation of these species by molecular techniques, we analyzed the sequence of 9 % of the mitochondrial DNA (Control Region and COI) of individuals from the Loa River (21º41' S) to the Valdivia River (39º50' S), adding meristic features for B. microlepidotus and B. australis in order to study population variation to clarify the taxonomy of the native species of the genus. The phylogenetic analysis showed that the individuals of Basilichthys semotilus form an haplogroup separated from the other species of the genus; however, B. australis and B. microlepidotus form a monophyletic group that shares the most common haplotypes. An analysis of meristic information showed no statistically signifi cant differences in the number of lateral line scales or number of rays in the fi ns between B. microlepidotus and B. australis. These results do not support the current classifi cation for the latter two species; there appears to be one group in the extreme north of the country (Basilichthys semotilus) and a second group in central Chile which should be called B. microlepidotus. This information will be useful to review the conservation status of the Chilean fauna.Key words: COI, Control Region, drainages, mtDNA, Silverside fi sh. RESUMENSi bien aún existen dudas sobre el número de especies descritas en el país, se reconoce que el 64 % de la ictiofauna dulceacuícola chilena se encuentra en alguna categoría de peligro de conservación. Uno de los grupos categorizados como vulnerable y en peligro de extinción es el de los pejerreyes del género Basilichthys. A lo largo Chile, este género posee tres especies morfológicas con distribución disjunta: Basilichthys semotilus, B. microlepidotus y B. australis. Las dos últimas sobreponen su distribución en el río Aconcagua y no son fácilmente diferenciables morfológicamente. Para evaluar la efi cacia en la identifi cación de estas especies al utilizar marcadores moleculares, se analizó el 9 % del ADN mitocondrial (Región Control y COI) de organismos obtenidos desde el río Loa (21º41' S) al río Valdivia (39º50' S) y adicionando un análisis merístico en organismos pertenecientes a las especies B. microlepidotus ...

Liver transcriptome characterization of the endangered freshwater silverside Basilichthys microlepidotus (Teleostei: Atherinopsidae) using next generation sequencing

“…Basilichthys microlepidotus is an atherinopsid endemic to Chile that inhabits lakes and rivers from 28°S to 39°S (Quezada-Romegialli et al, 2010;Veliz et al, 2012). It is a microphagous species, feeding on insect larvae, small invertebrates, filamentous algae and detritus (Duarte et al, 1971).…”

Evaluating taxonomic homogenization of freshwater fish assemblages in Chile

“…We thus welcome further taxonomic and phylogenetic assessments to validate this issue. Indeed, recent phylogeographic studies of native Orestias, Basilichthys, Hatcheria, Trichomycterus, and Aplochiton have provided molecular evidence for increasing or decreasing the number of taxa, and such evidence is incorporated in our analyses to the extent of our knowledge (e.g., Vila 2006;Unmack et al 2009;Quezada-Romegialli et al 2010;Vila et al 2011;Véliz et al 2012;Alò et al 2013). Regarding our choice of Sørensen's index, this has been sometimes criticized as it may fail to distinguish the effects of species turnover and species richness on beta diversity (Baselga 2010, Carvalho et al 2012, Baisier et al 2012).…”

Requirements and boundary conditions for fish passes of non-sport fish species based on Chilean experiences

“…Aplochiton zebra Jenyns Endangered Conservation status is based on the official governmental classification (Ministerio de MedioAmbiente) a Endemic species b Includes the probably synonym species Brachygalaxias gothei c Includes Basilichthys australis, species recently synonymized by Véliz et al (2012) Rev Environ Sci Biotechnol nocturnal species is represented by adults of Diplomystes, which seems to prefer environments characterized by high turbulent kinetic energy, low velocity in the longitudinal and vertical component, but high in the transverse component. Also they perform relative long distance travels (Piedra et al 2012), consistent with a very high gene flow along large rivers (Victoriano et al 2012).…”