Phylogeny of the neotropical armored catfishes of the subfamily Loricariinae (Siluriformes; Loricariidae)

Abstract

Evidence for the monophyly of Loricariinae is presented using phylogenetic analysis (maximum parsimony in PAUP) of osteological and external morphological characters. The two different analyses used, with the characters unordered and the characters partly ordered, produced the same levels of relationship among the ingroup taxa, displaying similar support (similar values of decay index and bootstrap). The analyses showed differences in the Loricariinae sister group. In the unordered analysis, the sister group of the Loricariinae is a clade formed by representatives of Hypostominae, Ancistrinae and Hypoptopomatinae. In the ordered analysis, Neoplecostomus came out as the sister group of Loricariinae. Loricariinae is diagnosed by a large set of synapomorphies under both data sets. Loricariinae is subdivided in two large clades, Loricariini Bonaparte, 1831 and Harttini Boeseman, 1971, which basically comprise the genera originally assigned. Loricariini comprises two subclades here named after already available taxa, Hemiodontichthyna (Isbrücker, 1979) and Planiloricariina (Isbrücker, 1979, 1980), plus the genera Loricaria, Spatuloricaria and the non--monophyletic Rineloricaria. Harttiini comprises two subclades, Farlowellina (Fowler, 1958) and Harttiina (Boeseman, 1971), plus the genus Sturisomatichthys. In Planiloricariina, Clossoloricaria came out non-monophyletic, and Crossoloricaria and Apistoloricaria are synonymized to Rhadinoloricaria, since these taxa are supported separately, but as clade. All taxa inside Loricariinae are diagnosed phylogenetically. The phylogenetic results are discussed under the current systematics for the group. Taxa not available for the analyses were tentatively placed within the phylogenetic hypothesis proposed. New systematic accounts are provided. The co-occurrence of extreme sets of apomorphies is discussed . Due to the positive correlation between sex dimorphic traits and monophyletic groups, a hypothesis on origin of dimorphic traits in Loricariinae is inferred.