Taxonomy and miniaturization of South American darters of the subfamily Crenuchinae Günther, 1864 (Crenuchidae, Characiformes): analysis of type specimens

• Grant number: 25/19552-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: November 01, 2025
• End date: February 01, 2026
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Murilo Nogueira de Lima Pastana
• Grantee: Michael Martins Romangnoli
• Supervisor: Diego Francisco Biston Vaz
• Host Institution: Museu de Zoologia (MZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Natural History Museum, London, England
• Associated to the scholarship: 24/23109-2 - Phyogenetic interrelationships, evolution and miniaturization in Crenuchinae Günther, 1864 (Crenuchidae, Characiformes), BP.MS

Abstract

Crenuchinae is a subfamily of South American darters (Crenuchidae: Characiformes) that includes five valid species. It encompasses both miniaturized taxa (i.e., not exceeding 26 mm in standard length) and species of significant value in the aquarium trade, such as the sailfin and black morpho tetras (genera Crenuchus and Poecilocharax, respectively). Of the four valid Poecilocharax species, two were described recently and are critically endangered and known only from Apuí, a municipality with one of the highest deforestation rates in Brazil. In addition, collecting efforts conducted in Santa Isabel do Rio Negro and São Gabriel da Cachoeira recorded a fifth, still undescribed miniature species of Poecilocharax, which was initially identified as P. weitzmani but displays unique characteristics in color pattern, as well as external and internal morphology. Due to the historical context in which they were described, the first three species described within Crenuchinae had their type series deposited exclusively in collections in North America and Europe, with no specimens available in South American museums. This imposes an obstacle to the analysis of this material, which is essential to comparisons and description of new species within the group. The present proposal aims to visit museums that house type specimens of Crenuchinae, collect morphological data from the type series of C. spilurus, P. bovalii, and P. weitzmani, describe a new species of South American darter genus Poecilocharax, and use collected data to support future taxonomic research in the subfamily.