Meridiorhantus orbignyi (Balke, 1992)



Taxonomy & Nomenclature

Synonym/s: Dytiscus nitidus Brullé, 1838; Dyticus (Meladema) nitidus Brullé, 1838 [orth. error]; Rhantus orbignyi Balke, 1992


Conservation Status

Last record: before 1996

Rediscovered after 1996

IUCN RedList status: Extinct


This species has been observed on at least 3 occasions since 2000 (Alarie et al. 2009:40; Fernández & Ruf, 2006:146). It was listed as extinct by (World Conservation Monitoring Centre, 1996), so either it has been rediscovered since 1996 or it was never in danger of being extinct and the World Conservation Monitoring Centre were wrong when they evaluated this species as extinct. Until the situation surrounding its historical status is clarified I have placed it into the rediscovered species database on account of its being declared extinct by the IUCN, and then more recent observations of the species taking place.



Argentina and Brazil


Biology & Ecology










Original scientific description:

Balke, M. (1992). Taxonomische Untersuchungen an neotropischen Wasserkäfern der Gattung Rhantus Dejean (Insecta: Coleoptera: Dytiscidae). Reichenbachia 29(6): 27-39.


Other references:

Alarie, Yves et al. (2009). Larval morphology of Rhantus Dejean, 1833 (Coleoptera: Dytiscidae: Colymbetinae): descriptions of 22 species and phylogenetic considerations. Zootaxa 2317: 1-102.

Anonymous. (2020). A register of extinct beetles. Latissimus 45: 26-28.

Baillie, J. and Groombridge, B. (eds). 1996. 1996 IUCN Red List of Threatened Animals. pp. 378. International Union for Conservation of Nature, Gland, Switzerland and Cambridge, UK.

Balke, M., Hájek, J. and Hendrich, L. (2017). Generic reclassification of species formerly included in Rhantus Dejean (Coleoptera, Dytiscidae, Colymbetinae). Zootaxa 4258: 91-100.

Brullé, G. A. (1938). Famille des Dyticiens. pp. 46-51 in: E. Blanchard & G.A. Brullé Insectes de l’Amérique Méridionale par Alcide d’Orbigny 6 (2). P. Bertrand: Paris.

Fernández, Liliana A. and Ruf, Mónica L. López. (2006). Aquatic Coleoptera and Heteroptera inhabiting waterbodies from Berisso, Buenos Aires province, Argentina. Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) 54(1): 139-148.

Groombridge, B. (ed.). 1994. 1994 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland and Cambridge, UK.

World Conservation Monitoring Centre. (1996a). Rhantus orbignyi. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. ( Downloaded on 25 August 2012.

World Conservation Monitoring Centre. 1996b. Rhantus orbignyi. The IUCN Red List of Threatened Species 1996: e.T19461A8894689. Accessed on 14 June 2022.


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