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| Malagodon honahona Carr, Martin & Sparks, 2024 DOI: 10.1206/4012.1 |
Abstract
A new species belonging to the recently described genus Malagodon Meinema and Huber, 2023, is herein described from specimens collected in a single, small, isolated Pandanas swamp in southeastern coastal Madagascar, located within the Réserve Spéciale de Manombo, south of the town of Farafangana, its only known locality. The new species was last collected in the late 1990s, and despite repeated attempts over the past three decades, no additional specimens have been collected at the type locality or from any other suitable habitats within the region, and the species is presumed to be extinct. The new species is distinguished from its only congener, Malagodon madagascariensis, formerly known from forested swamps in northeastern coastal Madagascar, and also now considered to be extinct, by the following apomorphic features: a lower anal-fin ray count (15–17 vs. 18–19), a longer caudal peduncle (26.8%–39.8% vs. 21.9%–26.7% SL), and the presence of a platelike (vs. thin and spinelike) neural spine on the fifth vertebral centrum in both sexes. Additionally, the new species exhibits neural spines on both the sixth and seventh vertebral centra that are also somewhat expanded and platelike dorsally compared with those in M. madagascariensis, which are narrow and spinelike. We also provide a rediagnosis of Malagodon based on the examination of additional material unavailable in the original description, which was based on only three specimens (two males of M. madagascariensis and one female of the new species).
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| Live adult male Malagodon honahona, UMMZ 240245, holotype, 23.9 mm SL, photographed shortly after capture. (Photo by P. Reinthal and J.S. Sparks.) |
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| Malagodon honahona, new species, holotype, UMMZ 240245, adult male, 23.9 mm SL. Réserve Spéciale de Manombo, southeastern coastal Madagascar. Preserved in ethanol. |
Malagodon honahona, new species
Diagnosis: The new species is readily distinguished from Malagodon madagascariensis, its only congener, by the following apomorphic features: lower anal-fin ray count (15–17 vs. 18–19), longer caudal peduncle (26.8–39.8 vs. 21.9–26.7% SL), and notably expanded and platelike neural spine on arch of fifth vertebral centrum in both sexes (vs. thin and spinelike in M. madagascariensis). In addition, neural spines on both sixth and seventh vertebral centra in new species also somewhat expanded and platelike dorsally versus narrow and spinelike in P. madagascariensis.
Etymology: Named for the swampy Pandanas dominated habitat in which this species occurred within the Réserve Spéciale de Manombo, in southeastern coastal Madagascar. Hohahona translates as swamp or swampy in Malagasy. The epithet, honahona, is used as a noun in apposition.
Emily M. Carr, Rene P. Martin and John S. Sparks. 2024. A New Extinct Species of Malagodon (Cyprinodontiformes: Pantanodontidae) from Southeastern Coastal Madagascar, with a Discussion of its Phylogenetic Relationships and a Redescription of the Genus. American Museum Novitates. (4012), 1-16. DOI: 10.1206/4012.1