Cyanogaster noctivaga is a species of characin native to the Rio Negro, Brazil.[1] This species is the only known member of the genus Cyanogaster and its scientific name translates as the blue-bellied night wanderer, referring to its unique appearance and nocturnal habits.[2] It was first described in 2013, having been discovered in October 2011 on a scientific expedition organised by the University of São Paulo, Brazil.[3]

Cyanogaster
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Cyanogaster
Mattox, Britz, Toledo-Piza & Marinho, 2013
Species:
C. noctivaga
Binomial name
Cyanogaster noctivaga

Description

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When alive, Cyanogaster noctivaga is a transparent fish with a blue belly and reddish gill covers, but it quickly loses its bright colours after death. Its eyes are large, and the shape of its snout and its dentition differs from other characins, marking it out as a new genus. The longest specimen found was 17.4 mm (0.69 in) long.[2] It differs from other members of the subfamily Stevardiinae in having 8 dorsal-fin rays and four teeth in the inner premaxillary tooth series and i+5 pelvic-fin rays and the presence of a single conical tooth in the outer premaxillary tooth series. There are hooks on the rays of the pelvic and anal fins in mature males.[3]

Distribution and habitat

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This fish is only known from a single location in the Rio Negro, but as it is a very small fish and seems to be entirely nocturnal, it is easily overlooked. It was found in an acidic backwater, a similar habitat to that of the smallest known species of fish, Paedocypris progenetica, which occurs in peaty forest swamps and blackwater streams in Asia.[2][4]

References

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  1. ^ Thomaz AT, Arcila D, Ortí G, Malabarba LR (2015). "Molecular phylogeny of the subfamily Stevardiinae Gill, 1858 (Characiformes: Characidae): classification and the evolution of reproductive traits". BMC Evolutionary Biology. 15: 146. doi:10.1186/s12862-015-0403-4. PMC 4509481. PMID 26195030.
  2. ^ a b c Da Silva, Y. (2013). "Blue-bellied fish is a surprise catch". Natural History Museum.
  3. ^ a b Mattox G, Britz R, Toledo-Piza M, Marinho M (2013). "Cyanogaster noctivaga, a remarkable new genus and species of miniature fish from the Rio Negro, Amazon basin (Ostariophysi: Characidae)". Ichthyological Exploration of Freshwaters. 23 (4): 297–318.
  4. ^ Kottelat M, Britz R, Tan HH, Witte K (2005). "Paedocypris, a new genus of Southeast Asian cyprinid fish with a remarkable sexual dimorphism, comprises the world's smallest vertebrate" (PDF). Proceedings of the Royal Society B: Biological Sciences. 273 (1589): 895–899. doi:10.1098/rspb.2005.3419. PMC 1560243. PMID 16627273. Archived from the original (PDF) on 2009-07-12. Retrieved 2015-05-04.