Work

A new killifish of the genus Laimosemion (Cyprinodontiformes, Rivulidae) from Rio Cajari in the Brazilian Amazon

Year: 2026

Type: article

Abstract: Based on morphological and molecular evidence, this study describes a new species of rivulid of the genus Laimosemion from the lower Rio Amazonas Basin in the south of the state of Amapá in northern Brazil. The new species, Laimosemion laranja sp. nov ., exhibits a color pattern characteristic of the L. geayi species group, consisting of longitudinal rows of spots on the anterior portion of flank and oblique chevron-shaped bars on the posterior portion of flank. It can be distinguished from its congeners by unique combination of characters, including position of dorsal-fin origin relative to anal-fin rays, frontal squamation pattern of head, counts of transverse and longitudinal scale series, fin-ray counts, vertebral count, osteology of caudal fin, and number of neuromasts in infraorbital series. Partial sequences of the mitochondrial cytochrome c oxidase subunit I ( cox1 ) gene indicates that the new species diverges genetically by 5.3% from its closest relatives, L. agilae and L. strigatus , by 9.2% from L. dibaphus , and 12.3% from L. geayi . We further discuss the systematic relationships within the L. geayi species group and the conservation status of the new species based on IUCN criteria, including recommendations for its conservation.

Source: Zoosystematics and Evolution

DOI: 10.3897/zse.102.187659

Authors: Yuri Gomes Abrantes, Sergio Maia Queiroz Lima, Dalton Tavares Bressane Nielsen, Fabio Origuela de Lira, Márcio Joaquim da Silva, Waldir Miron Berbel-Filho

Institutions: Universidade Federal do Rio Grande do Norte, Universidade Federal do Pará, University of West Florida, University of Oklahoma

Language: English

Topic: Fish biology, ecology, and behavior

Subfield: Nature and Landscape Conservation

Field: Environmental Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,078