Diversidade de chydoridae (crustacea: cladocera) de ambientes bentônicos e intersticiais do estado do Maranhão, Brasil.

Abstract

The study of aquatic biodiversity is of paramount importance for understanding ecosystem dynamics and for developing tools to support the conservation of these habitats. In this context, Cladocera, a monophyletic superorder of branchiopod microcrustaceans with Paleozoic origins, represents a key group. These organisms play crucial ecological roles, contributing to nutrient cycling and serving as important links in aquatic food webs. Within this group, the family Chydoridae harbors more than half of the known species, predominantly occupying benthic environments. Despite their wide representation, the family still presents significant knowledge gaps, especially in neotropical regions such as Brazil. In the state of Maranhão, although studies on cladocerans already exist, more comprehensive surveys are still needed, covering a broader range of locations and sampling environments. This study aimed to investigate the diversity of Chydoridae (Crustacea: Cladocera) in the state of Maranhão, with the goal of expanding knowledge about the local fauna and conducting collections in understudied habitats. The objective was to document previously unrecorded species and carry out in depth morphological investigations to address taxonomic uncertainties. As a result, new occurrences were recorded, and detailed morphological studies were conducted. The results were consolidated into three articles published in specialized scientific journals. The first reports the first record of Kurzia media in Brazil, and the second in South America. The material was collected in the municipality of Bacabal-MA. In addition, the study presents considerations on the taxonomic history of the species and discusses the need for a formal redescription and the designation of a neotype. The second result involved the first record of Camptocercus dadayi Stingelin, 1913, in Maranhão, based on collections from the municipality of Buriti-MA, and also the confirmation of its presence in Chile, through the analysis of specimens from the Province of Cautín. The third result refers to the analysis of morphological variation in Camptocercus dadayi across different South American populations. Significant variation was observed in the morphology of the postabdomen, particularly in the patterns of marginal denticles, lateral fascicles, and the terminal claw. These findings broaden the understanding of the geographic and morphological distribution of Chydoridae in the state of Maranhão and, consequently, in Brazil.