Morphological analysis of Trichomycterus areolatus Valenciennes, 1846 from southern Chilean rivers using a truss-based system (Siluriformes, Trichomycteridae)

Abstract

Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA) and discriminant function analysis (DFA). It is hypothesized that populations must segregate morphologically from each other based on the river basin that they were sampled from, since each basin presents relatively particular hydrological characteristics. Significant morphological differences among the three populations were found with PCA (ANOSIM test, r = 0.552, p < 0.0001) and DFA (Wilks’s λ = 0.036, p < 0.01). PCA accounted for a total variation of 56.16% by the first two principal components. The first Principal Component (PC1) and PC2 explained 34.72 and 21.44% of the total variation, respectively. The scatter-plot of the first two discriminant functions (DF1 on DF2) also validated the existence of three different populations. In group classification using DFA, 93.3% of the specimens were correctly-classified into their original populations. Of the total of 22 transformed truss measurements, 17 exhibited highly significant (p < 0.01) differences among populations. The data support the existence of T. areolatus morphological variation across different rivers in southern Chile, likely reflecting the geographic isolation underlying population structure of the species.

Morphological plasticity in a wild freshwater fish,&nbsp;Systomus&nbsp;sarana&nbsp;(Cyprinidae) from India: a glimpse through advanced morphometric toolkits&nbsp;

“…Therefore, in a geographically vast country like India having a number of isolated rivers, there is more possibility of variations among sh populations, which can be clearly depicted in the present study. The present study is in agreement with previous studies conducted with the same objective of detecting intraspecies morphological differences in other cyprinids [69][70][71][72] and non-cyprinids [49,73,74] Though, there are also reports on low morphometric divergences despite of geographically isolated populations [75]. Hence, patterns of morphological structure in shes differed between river basins/rivers/river stretches.…”

Genomic Selection in Aquaculture: Application, Limitations and Opportunities With Special Reference to Marine Shrimp and Pearl Oysters

“…Furthermore, fish skin or fillet color and pearl quality traits (e.g., color, luster, and complexion), which are traditionally recorded as categorical traits, can now be recorded as highly reliable continuous quantitative traits based on ultraviolet-vis spectrophotometry measurements (e.g., Urban et al., 2013; Kustrin and Morton, 2015). The performance of MVS and traditional color measurements has been compared with Atlantic salmon, rainbow trout, and pearls with spectral patterns produced by MSV more representative and consistent of the real color (Yagiz et al., 2009; Mamangkey et al., 2010; Colihueque et al., 2011, 2017; Toyota and Nakauchi, 2013), which will ultimately improve genomic selection predictions.…”

Stock Identification of Short Mackerel (Rastrelliger brachysoma) in the Upper and Middle Gulf of Thailand by Morphological Characters

“…Furthermore, the transient behavior of mackerel may be conducive to the conglomeration of fish from different populations. Colihueque et al [26] found that the morphometric variations of Trichomycterus areolatus Valenciennes 1846 might be associated with variations in habitat [27].…”