Pseudocorynopoma stanleyi Malabarba, Chuctaya, Hirschmann, Oliveira & Thomaz, 2020

Serra, Wilson S., Scarabino, Fabrizio, Furtado, Giovanni, Sanguinetti, Germán & Caligari, Mauricio, 2021, Fighting faunistic chaos: confirmations and new records for Uruguayan Characidae (Ostariophysi: Characiformes)., Ichthyological Contributions of PecesCriollos 77, pp. 1-9 : 4-5

Pseudocorynopoma stanleyi Malabarba, Chuctaya, Hirschmann, Oliveira & Thomaz, 2020

figs. 5 , 6

Examined material: Uruguay: Cerro Largo: MHNM 1024, 1 ex., 44.3 mm SL, Arroyo Corrales, 33°01'33"S 54°06'47"W, E. Messner, 27/I/1962; MHNM 1075 , 3 ex., 32.3-45.5 mm SL, cañada cerca de Arroyo Coronilla, al sur de Río Branco , aprox. 32°36'07"S 53°20'48"W, col. E. Messner , 15/IV/1962; MHNM 1090 , 2 ex., 48.6-51.9 mm SL, cañada en Camino entre Río Branco y Dragón , col. E. Messner , 16/IV/1962; MHNM 4368 , 1 ex., 51.2 mm SL, Paso Sarandí, 32°26'25"S 53°36'46"W, Arroyo Sarandí de Barceló , col. W.S. Serra, G. Furtado & A. Balao , 1/IV/2018; MHNM 4428 , 1 ex., 51.2 mm SL, Río Yaguarón , 32°31'01"S 53°27'27"W, col. W.S. Serra, G. Furtado & A. Balao , 30-31/III/2018. Lavalleja: MHNM 2745 , 1 ex., 50.3 mm SL, Arroyo Polanco , 33°52'07"S 55°07'11"W, col. L.H. Amato , 25/X/1980; MHNM 4418 , 1 ex., 37.5 mm SL, Arroyo Polanco , 33°52'07"S 55°07'11"W, 1981 . Rocha. MHNM 928 , 8 ex., 43.8-50.3 mm SL, Ruta 16, “2° arroyo que cruza la carretera (Castillos)”, aprox. 34°09'S 53°50'W, col. E. Messner ; MHNM 932 , 1 ex., 52.4 mm SL, Ruta 16, “2° arroyo que cruza la carretera (Castillos)”, aprox. 34°09'S 53°50'W, col. E. Messner ; MHNM 1307 , 2 ex., 39.6-41.9 mm SL, afluente de Laguna Negra, cruza Camino de los Indios , aprox. 33°54'S 53°43'W, col. E. Messner , 9/IX/1962. MHNM 2743 , 1 ex., 35.5 mm SL, Arroyo del Pescado , 33°58'24"S 53°45'04"W, col. E. Messner ; MHNM 2747 , 4 ex., 45.5-68.1 mm SL, Playa de la Angostura, Laguna Negra , aprox. 34°04'S 53°38'W, col. Skuk, Rodríguez & Amato , 20/I/1982; MHNM 4424 , 1 ex., 34.3 mm SL, nameless stream, 34°09'41"S 53°50'27"W, col. W.S. Serra & G. Furtado , 17/XII/2020; MHNM 4425 , 3 ex., 52.0- 56.1 mm SL, Paso del Bañado, Ruta 16 km 18.400, 34°07'37"S 53°50'18"W, col. W.S. Serra & G. Furtado , 17/XII/2020; MHNM 4426 , 4 ex., 26.6-54.2 mm SL, Paso del Bañado, Ruta 16 km 18.400, 34°07'37"S 53°50'18"W, col. W.S. Serra & G. Furtado , 17/XII/2020. Treinta y Tres: MHNM 1039 , 1 ex., 52.8 mm SL, “A° Malo, A° Yerbal y otro de Río Olimar Grande ”, aprox. 33°S 54°W, col. E. Messner.

This species differs from other congeners of the genus by the following combination of characters: 32-36 branched anal fin rays, presence of an intermediate lobe in the distal margin of the anal fin of males, and males with absence of black spots at the distal tip of the pectoral fin and the tip of the anterior lobe of the anal fin (Malabarba et al. 2020). Specimens analyzed present all these characters and come from eastern and northeastern Uruguay, associated to Merín Lagoon basin ( fig. 7 ). The previously known distribution of P. stanleyi extended through Patos-Merin Lagoon basin and Tramandaí system in Rio Grande do Sul, Brazil (Malabarba, et al. 2020).

Described in late 2020 and recorded with numerous lots from all Patos-Merin Lagoon basin in Rio Grande do Sul, P. stanleyi was expected to also be present in the Uruguayan region of the same basin, especially considering published records ( Azpelicueta & García 2001; Serra et al. 2020) and numerous photographs from social media (“Peces Argentinos” Facebook’s group, e.g. Figure 6) of “ Pseudocorynopoma doriae ” from this area. Specimens here analyzed confirm with vouchers the presence of the species for Uruguayan territory.

Figures

fig. 5 Pseudocorynopoma stanleyi before and after fixation: fig. 6 Male and female of Pseudocorynopoma stanleyi from MHNM 4430, 51.2 mm SL, Río Yaguarón, 32°31'01"S Castillos (Rocha, Uruguay), maintained in aquarium, 53°27'27"W, Cerro Largo, Uruguay not preserved. Pictures posted by Andrés Balao in the Facebook group of “Peces Argentinos”, on September 21st of 2017.

fig. 7 Distribution map of the recorded species: yellow = Aphyocharax rathbuni; green = Oligosarcus robustus; red = Psalidodon erythropterus; blue = Pseudocorynopoma stanleyi. Triangles = records from Uruguay; circles = records from outside Uruguay based on literature. Py. = Paraguay; Uy. = Uruguay.