Abstract
The systematics of the Glandulocaudinae is reviewed in detail and justification for the recognition of the group as a subfamily is discussed. The subfamily Glandulocaudinae consists of three genera: Lophiobrycon with one species plesiomorphic in some anatomical features but some others exclusively derived relative to the species in the other genera; Glandulocauda with two species intermediate in phylogenetic derivation; and Mimagoniates with seven species (one new), all more phylogenetically derived concerning their pheromone producing caudal-fin organs and with other anatomical characters presumably more derived than in the species of the other genera. Glandulocauda melanogenys Eigenmann, 1911, is considered a junior synonym of Hyphessobrycon melanopleurus Ellis, 1911. A replacement name, Glandulocauda caerulea Menezes & Weitzman, is proposed for G. melanopleura Eigenmann, 1911. Gland cells found in the caudal-fin organs of all species are histologically indistinguishable from club cells and probably secrete a pheromone during courtship. The club cells are associated with somewhat modified to highly derived caudal scales forming a pheromone pumping organ in the more derived genera and species. This subfamily is distributed in freshwaters of eastern and southern Brazil, Paraguay, and northeastern Uruguay.
Highlights
The species of the Glandulocaudinae are distributed in parts of eastern and southern Brazil, Paraguay, and northeastern Uruguay
We suggest that graphs comparing such plots are useful for identifying clines of data from a series of isolated populations that are geographically arranged in a linear fashion, for example see our treatment of the series of geographically adjacent populations of Mimagoniates microlepis
As briefly discussed by Weitzman et al (2005: 345) the Glandulocaudinae defined in this paper corresponds to the Glandulocaudini of Menezes & Weitzman (1990) and may have evolved independently of the Stevardiinae from a Knoduslike ancestor based on their different morphology
Summary
The species of the Glandulocaudinae are distributed in parts of eastern and southern Brazil, Paraguay, and northeastern Uruguay. They are all attractively colored, relatively small fishes, usually about 28-60 mm in standard length as adults. Some species may be threatened with extinction and one may already be extinct due to relatively recent habitat alterations, primarily deforestation, by man. We comment on these problems in the species accounts and summarize them in a general section on conservation and ecology of the species of the subfamily
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