Redescription of Astyanax brevoortii (Gill, 1858) (Characiformes, Characidae) and description of three new species of Astyanax subgenus Poecilurichthys, Caribbean Sea, Venezuela

In Astyanax (Poecilurichthys), we recognize six species-groups defined by the distribution of melanophores on the body: 1. bimaculatus; 2. rupununi; 3. abramis: 4. orthodus; 5. asuncionensis; and 6. anterior, which are named for a representative species. Astyanax brevoortii1 is redescribed using specimens from Trinidad (including types). This species, as a member of the bimaculatus species-group, is distinguished by lacking a concentration of melanophores outlining the scale margins on the sides of body. Three new species of the bimaculatus species-group are described: A. caroni n. sp. from the Caroni River drainage, which differs in having all of the teeth of the internal premaxillary series pentacuspid (vs. heptacuspid), and the length of the caudal-peduncle spot which is less than two times the eye diameter (vs. at least twice eye diameter). A. garuttii n. sp. from the San Juan River and Gulf of Cariaco drainages is distinguished by osteological characters and by morphological characters identified by principal component analysis. A. cuyuni n. sp. from the Cuyuni River (Essequibo River Basin), is distinguished by having a foramen in the pterotic and sphenotic bones (vs. absent), and the shape of the last two neural spines that form a posteriorly directed arc, that covers the epineurals.