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| Mesoaphyosemion izyarae Ott, Sonnenberg & Van der Zee, in Sonnenberg, Ott, Rodriguez, Olias, Martinez et Van der Zee, 2026. |
Abstract
Mesoaphyosemion izyarae sp. nov., is described from a small left-bank tributary of the Mitemele River in southern Equatorial Guinea. The new species is distinguished from all other described Mesoaphyosemion species by a unique combination of male colouration characters: dorsal fin yellow with red streaks between fin rays; anal and pelvic fins yellow with black or dark red margin, basally light blue, caudal fin in centre black with red streaks between fin rays, broad yellow area on dorsal and ventral margin, body metallic light blue with more or regular rows of red dots on side, posteriorly denser and forming a reticulated pattern. The species status is supported by mtDNA analyses, including nine of the eleven described valid Mesoaphyosemion species.
Pisces, phylogeny, colour pattern, taxonomy, mtDNA, Rio Mitemele, Pleistocene rainforest refuge
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| Mesoaphyosemion izyarae. Male (1) and female (2) from the type locality, Rio Mveň basin, near the village of Efulan, Equatorial Guinea (not preserved). |
Mesoaphyosemion izyarae sp. nov., Ott, Sonnenberg & Van der Zee
Diagnosis. Mesoaphyosemion izyarae shares with other species of the genus a combination of the following characteristics in the male: a mostly metallic pale blue, blue or blue-green colouration on the sides; an often variable pattern of red dots on sides, in most species irregularly distributed, in others forming more or less regular stripes or blotches; a latero-ventral red line on the caudal peduncle; unpaired fins without, or with only short, fin extensions, caudal fin nearly straight, slightly rounded or weakly trilobate; no conspicuous markings on ventral side of the head; adults have a yellow snout. Unfortunately, none of these characteristics is diagnostic on its own as they are also known from other nothobranchiid genera or species groups but, in combination, they are significant.
Mesoaphyosemion izyarae is distinguished from all other known Mesoaphyosemion species by a unique combination of colour pattern features in the male: dorsal fin yellow with red streaks between fin rays; anal and pelvic fins yellow with black or dark red margin, basally light blue, caudal fin black in...
RAINER SONNENBERG, HEINZ OTT, ADOLFO GONZALEZ RODRIGUEZ, CARLOS VIZCAINO OLIAS, FRANCISCO PORTAL MARTINEZ and JOUKE R. VAN DER ZEE. 2026. Description of Mesoaphyosemion izyarae (Cyprinodontiformes: Nothobranchiidae), A New killifish Species from southern Equatorial Guinea. Zootaxa. 5759(4); 453-463. DOI: doi.org/10.11646/zootaxa.5759.4.5 [2026-02-18]
