Hyphessobrycon melanopleurus uruguayensis Messner, 1962 Hyphessobrycon melanopleurus uruguayensis Messner (1962)

Malabarba, Luiz R., Weitzman, Stanley H. & Litz, Thomas, 2004, Scientific note Hyphessobrycon melanopleurus uruguayensis Messner, 1962, an available name and a senior synonym of Cyanocharax macropinna Malabarba & Weitzman, 2003 (Ostariophysi: Characidae), Neotropical Ichthyology 2 (2), pp. 99-102 : 100-101

The status of Hyphessobrycon melanopleurus uruguayensis Messner, 1962

Weitzman & Palmer (1997), while reviewing a subgroup of Hyphessobrycon , recognized the species described by Fowler (1943) as Megalamphodus (Ectrepopterus) uruguayensis as valid, and belonging to a clade designated by them as the Rosy-tetras. Weitzman & Palmer (1997) listed the species of Fowler in a new combination, Hyphessobrycon uruguayensis ( Fowler, 1943) . Through their action, Hyphessobrycon melanopleurus uruguayensis Messner, 1962 , even though described as a subspecies, would become a secondary junior homonym and invalid, according to ICZN (1999: article 53.3). Thus the usage of both Hyphessobrycon melanopleurus uruguayensis Messner (1962) along with the usage of Hyphessobrycon uruguayensis ( Fowler, 1943) in the lists published latter by Nion et al. (2002:11) and Reichert-Lang (2002) were erroneous.

The type material of Hyphessobrycon melanopleurus uruguayensis Messner (1962)

No types were designated in the diagnosis of Hyphessobrycon melanopleurus uruguayensis and only a broad reference was given to the locality of the examined specimens: “hasta ahora lo he encontrado solamente en la viertente del R. Uruguay ” [up to now I have found only in the rio Uruguay drainage – our translation]. However, two specimens were listed as syntypes by Olazarri et al. (1970) in the holdings of the Museo Nacional de Historia Natural de Montevideo, numbered CI 758 and CI 759, and were collected by Messner in the arroyo Tomás Cuadra (a tributary of the rio Negro, itself a lower tributary of the rio Uruguay), Durazno, Uruguay (Lat. –33.38333; Long. – 56.41667), that is herein recognized as the type locality of the species. There is no date of collection.

However, we recognize herein that Hyphessobrycon melanopleurus uruguayensis Messner belongs to the same species described as Cyanocharax macropinna by Malabarba & Weitzman (2003). According to the ICZN (1999: Article 59.2), if the junior species-group name has not been replaced and the taxa are no longer considered congeneric, the junior name is not to be rejected, even if one speciesgroup name was originally proposed in the current genus of the other. Thus, Hyphessobrycon melanopleurus uruguayensis Messner, 1962 , placed as a secondary junior homonym of Hyphessobrycon uruguayensis ( Fowler, 1943) by the action of Weitzman & Palmer (1997) as discussed above, is not to be rejected due to the action of Malabarba & Weitzman (2003) who considered its allocation to a different genus ( Cyanocharax ), and therefore we now refer to this species as Cyanocharax uruguayensis ( Messner, 1962) , new combination.

The two specimens listed as syntypes by Olazarri et al. (1970) are available at MHNM, and were examined by one of us (LRM). CI 759 is a female ( Fig. 1 ) identified in a hand written jar label as “ Hyphessobrycon melanopl . uruguay. allotypus ” ( Fig. 2 ). CI 758 ( Fig. 3 ) has no species determination but a hand written jar label ( Fig. 4 ) stating that “abandonado por no conocer sexo” [discarded due to unknown sex]. Both specimens belong to the same species described as Cyanocharax macropinna by Malabarba & Weitzman (2003). Due to the fact that CI 759 is identified in the hand written label as the “ allotypus ”, it seems reasonable to recognize that Messner had chosen a holotype, presently missing. The label of CI 758 stating that the specimen is “discarded due to unknown sex” does not make sure that the specimen does not belong to the type series, or only that it has not been selected as a primary type. Thus, we herein recognize both specimens as syntypes, as listed by Olazarri et al. (1970). Morphometric and meristic data of these syntypes are given in Table 1.

Characters that allows the recognition of Messner species as a senior synonym of Cyanocharax macropinna among Cyanocharax species are the large number of branched analfin rays (31-32 in the syntypes and 28-35, mostly 29-33 according to Malabarba & Weitzman, 2003) and the convex profile of the anal fin ( Figs. 1 , 3 ).

Figures

Fig. 1. Syntype of Hyphessobrycon melanopleurus uruguayensis Messner, 1962. MHNM 759, female, 33.2 mm SL.

Fig. 2. Original label found in the jar of the syntype of Hyphessobrycon melanopleurus uruguayensis Messner, 1962 catalogued under MHNM 759.

Fig. 3. Syntype of Hyphessobrycon melanopleura uruguayensis Messner, 1962. MHNM 758, possibly a male due to the large convexity of the anal fin, 35.3 mm SL.

Fig. 4. Original label found in the jar of the syntype of Hyphessobrycon melanopleurus uruguayensis Messner, 1962 catalogued under MHNM 758.