Biogeography of the freshwater fishes of the Guianas using a partitioned parsimony analysis of endemicity with reappraisal of ecoregional boundaries

Abstract

The Guianas are one of the most diverse regions of the Neotropics, hosting a particularly high rate of freshwater fish endemism. The present distributional patterns of freshwater fish species in the major catchments of the Guianas (comprising Guyana, Suriname and French Guiana) were analysed to reveal the faunal relationships between rivers, evaluate different hypotheses concerning biogeographical units, and redefine the boundaries of the Guianese freshwater ecoregions. A parsimony analysis of endemicity was performed using a data partitioning strategy to alleviate some drawbacks inherent to the method (e.g. long branch attraction artefact, heterotachy), and take into account alternative parsimony models assigning different constraints on state changes for the different species. A strong spatial element was present in the data with a structuring of species along a west-east gradient. Two main biogeographical units were highlighted: one to the west, ranging from the Essequibo to the Commewijne rivers and including the Proto Berbice and Surinamese regions, and one to the east ranging from the Maroni to the Oyapock rivers and including the Western, Central and Eastern French Guiana regions. Each ecoregion possessed distinctive fish assemblages, and three to four potential zones of faunal exchanges between Amazonian and Guianese rivers have been confirmed.

Scale(s) matter: Deconstructing an area of endemism for Middle American freshwater fishes

“…identification of river networks with shared endemics) within these larger regions are less often investigated (e.g. Lemopoulos & Covain, 2019; Smith & Bermingham, 2005), this is particularly true for freshwater fishes in the northern Neotropics.…”

Aquarium trade and fish farms as a source of non-native freshwater fish introductions in French Guiana

“…Among the 11 non-native fish species recorded on the Guianese territory, two species (Hyphessobrycon eques and Pterophyllum scalare (Schultze, 1823)) were not retrieved in their invasion range in recent records, and nine non-native species are therefore currently present in French Guiana. Among these species, four originate from coastal swamps of Amapá, Brazil and occasionally enter the Oyapock River (Jégu and Keith, 1999;Lemopoulos and Covain, 2019). They are therefore native from the Oyapock drainage basin, which main course represents the frontier between Brazil and French Guiana (Fig.…”

Loricaria cuffyi (Siluriformes: Loricariidae), a new species of loricariin catfish from the Guiana Shield

“…Although basins of the Guiana Shield are areas of great species richness and endemism (Alofs et al ., 2014; Lemopoulos & Covain, 2018; Lujan & Armbruster, 2011; Tedesco et al ., 2012), for more than 25 years they have been impacted by mining, which is an important source of income for the region (Laing, 2019). In these areas, conservation strategies for aquatic ecosystems and their fishes are increasingly inefficient (Reis, 2013), so much so that many species are already extinct in the wild before being described (Fontaine et al ., 2012).…”