Oreochromis aureus (Steindachner, 1864)

Angulo, Arturo, 2021, New records and range extensions to the Costa Rican freshwater fish fauna, with an updated checklist, Zootaxa 5083 (1), pp. 1-72 : 9

9) * Oreochromis aureus (Steindachner, 1864) ;

Cichlidae .

Blue Tilapia; Tilapia, Tilapia Azul ( Fig. 3C ).

Diagnosis: This exotic species differs from the other species of the family occurring in the freshwaters of the country by having three anal spines [vs. four or more in the other species, except Oreochromis niloticus (Linnaeus, 1758) and Andinoacara coeruleopunctatus (Kner, 1863) ]. From these, it differs by the following combination of characters: absence of iridiscent light blue-green spots and lines on the head and the anterior portion of the body (vs. present in A. coeruleopunctatus ); gill-rakers 18–26 (vs. 9–12 in A. coeruleopunctatus and 27–33 in O. niloticus ); dorsal fin spines 15–16 (vs. 13–14 in A. coeruleopunctatus and 16–18 in O. niloticus ); absence of dark vertical stripes on the caudal fin (vs. present in O. niloticus ).

Basis of the record: A single specimen was collected in the río Pacuar (Térraba River basin), 4 km SE of San Isidro del General, under bridge on road San Isidro-Dominical, San José (09.35264, -83.72790), at 619 m. a.s.l., on March 25, 2013 by Carlos Garita (UCR 3018-001).

Remarks: This species was introduced to the country by government agencies and private entities in an attempt to strengthen aquaculture activities. It is possible that this species is widely distributed in the country.

Figures

FIG. 3. New country records. (A) Mugil incilis, specimen captured in the Río Pacuare, near the mouth of the river, Siquirres, Limón (10.219424, -83.284898), at 8 m.a.s.l., on July 22, 2004, by Jorge Picado (UCR 2835-005). (B) Oligoplites saliens, specimen captured in the Caño Palma, near the Caño Palma Biological Station, Pococí, Limón (10.5938, -83.52731), at 11 m.a.s.l., on February 22, 2019, by Nathan Lovejoy et al. (UCR 3311-001). (C) Oreochromis aureus, specimen captured the Río Pacuar (Térraba river basin), 4 km SE of San Isidro del General, under bridge on road San Isidro-Dominical, San José (09.35264, -83.72790), at 619 m.a.s.l., on March 25, 2013 by Carlos Garita (UCR 3018-001). (D) Pangasianodon hypophthalmus, specimen captured in the laguna San Sebastian, Caño Negro, Alajuela (10.8630, -84.7807), at 41 m.a.s.l., on September 29, 2021, by Bryan Castro and Jader Urbina. (E) Rhencus macracanthus, specimen captured in the Río Lagarto, Chomes, Puntarenas (10.08320, -84.92064), at 15 m.a.s.l., on September 1, 1979, by William Bussing et al (UCR 1268-025). (F) Thalassoma bifasciatum, specimen captured in the Quebrada Cocles (Matina river basin), 2.5 km SE of Puerto Viejo, near the bridge on El Tucán-Cocles road, Limón (9.64221, -82.73588), at 22 m.a.s.l., on August 20, 2020, by Walter Carranza. (G) Trinectes fluviatilis, specimen captured in the Quebrada Cocal Amarillo, 5 Km N of Pavones, on the Puerto Pilón-Pavones road, Puntarenas (8.43643, - 83.09660), at 26 m.a.s.l., on March 30, 2021, by Arturo Angulo et al. (H) Trinectes xanthurus, specimen captured in the Río Tempisque (Tempisque river basin), at Puerto Humo, Guanacaste (10.31653, -85.35365), at 9 m.a.s.l., on January 25, 1976, by William Bussing et al. (UCR 0970-005). Range extensions. (I) Achirus declivis, specimen captured in the Río Moín, at the Puerto Fluvial JAPDEVA, Limón (09.99745, -83.08077), at 7 m.a.s.l., on December 14, 2006, by Karina Rodríguez (UCR 2761-003). (J) Amatitlania myrnae, specimen captured in the Río Estrella, Valle La Estrella, Limón (9.77552, -82.93240), at 13 m.a.s.l., on April 6, 2014, by Arturo Angulo. (K) Amphilophus citrinellus, specimen captured in the Río Bebedero, near Paso Real, Cañas, Guanacaste (10.43318, -85.15697), at 32 m.a.s.l., on August 7, 2021, by Luis Bolivar Montero-Chacón. (L) Brachyrhaphis olomina, specimens captured in an unnamed pound in the Reserva Biológica Monteverde, Altos de San Luis, Monteverde, Puntarenas (10.31667, -84.80932), at 1486 m.a.s.l., on July 6, 2019, by Arturo Angulo.