Gymnogeophagus Miranda Ribeiro

Synonymy

Gymnogeophagus Miranda Ribeiro, 1918. Revta Mus. paul. 10, p. 790 (type by monotypy Gymnogeophagus cyanopterus Miranda Ribeiro). — Masculine.

Gymnogeophagus rhabdotus. Photo: S.O. Kullander.

Diagnosis

Geophagine cichlids lacking supraneurals and having a prominent forwards directed spine distally on the first dorsal fin pterygiophore. The largest species is G. balzanii, attaining 169 mm SL; other species reach ca 90-150 mm SL.

Reis & Malabarba (1988), and Reis et al. (1992) revised the group and described or redescribed all known species. They distinguished three groups, reflected in the key below.

• Gymnogeophagus balzanii is very deep bodied and has scaled fins, 12-15 soft dorsal fin rays (8-12 in the other species), rostrocaudally shortened supraoccipital crest and the dorsal lobe of the caudal fin longer than the ventral lobe. It is a maternal mouth brooder.
• Gymnogeophagus gymnogenys, G. australis, G. labiatus, and G. lacustris are elongate species with 26-28 scales in a horizontal row. The breeding behaviour of G. australis is unknown. The others are maternal mouth brooders.
• Gymnogeophagus rhabdotus, G. setequedas and G. meridionalis are moderately deep-bodied species with 22-25 scales in a horizontal row, and more or less distinct blue horizontal stripes on the sides. The breeding behaviour of G. setequedas is unknown. The others are substrate brooders.

Included species

Gymnogeophagus australis (Eigenmann, 1907)

Gymnogeophagus balzanii (Perugia, 1891)

Geophagus duodecimspinosus Boulenger, 1895

Gymnogeophagus cyanopterus Miranda Ribeiro, 1918

Gymnogeophagus che Casciotta, Gómez & Toresanni, 2000

Gymnogeophagus gymnogenys (Hensel, 1870)

Geophagus camurus Cope, 1894

Gymnogeophagus labiatus (Hensel, 1870)

Geophagus bucephalus Hensel, 1870

Geophagus pygmaeus Hensel, 1870

Geophagus scymnophilus Hensel, 1870

Gymnogeophagus lacustris Reis & Malabarba, 1988

Gymnogeophagus meridionalis Reis & Malabarba, 1988

Gymnogeophagus rhabdotus (Hensel, 1870)

Gymnogeophagus setequedas Reis, Malabarba & Pavanelli, 1992

Key to species

Based on keys in Reis & Malabarba (1988) and Reis et al. (1992), modified (not including G. che).

1. Scales in horizontal scale row 22-25 ... 2
Scales in horizontal scale row 26-28 ... 4

2. Bright blue stripes along flanks conspicuous; conspicuous pattern of dots or small stripes on unpaired fins ... 3
Bright blue stripes along flanks hardly visible; colour pattern of unpaired fins faint, without conspicuous dots or stripes ... G. setequedas

3. Dorsal and anal fins with well-defined circular dots ... G. meridionalis
Dorsal and anal fins with small stripes ... G. rhabdotus

4. Dorsal fin with 12-15 soft rays; caudal fin almost completely scaled, with lateral line branch on the lower lobe ... G. balzanii
Dorsal fin with 8-12 branched rays; caudal fin width scales only on the proximal third or half, without lateral line branch on the lower lobe ... 5

5. Dark band extends posteroventrally from the dorsal fin origin; well-defined circular dots on dorsal, anal and especially caudal fins ... 6
Dark band from nape to cheek crossing the eye instead of the band described above; dorsal and especially caudal fins with rather small stripes ... 7

6. Dorsal profile of body anterior to dorsal fin origin very steep; soft dorsal fin scaly; caudal peduncle depth 0.9 in its length ... G. australis
Dorsal profile of body anterior to dorsal fin origin not as steep; soft dorsal fin rarely scaled; caudal peduncle depth 1.0-1.4 in its length ... G. gymnogenys

7. Lips thick, extremely well developed, lower lip deeply notched medially ... G. labiatus
Lips normal, not excessively developed or notched ... G. lacustris

Etymology

Gymnogeophagus, from the Greek word gymnos, naked, and the generic name Geophagus. It should be understood to refer to Geophagus like cichlids with naked (scaleless) cheek and predorsal midline.

Local names

Brazil: Acará, Cará, Caraá-cartola, Caraá-topete, Cará manteiga, Palometa; Uruguay: Castañeta, Chanchita; Argentina: Castañeda, Chanchita; Paraguay: Pirá mbocayá (Reis & Malabarba, 1988).

Geographical distribution

Restricted to southern tropical to subtropical South America. Gymnogeophagus balzanii has a wide distribution including the Paraguay drainage in Bolivia, Brazil and Paraguay, as well as the lower Paraná and Uruguay drainages in Argentina and Uruguay. Remaining species have limited ranges in S Paraguay, the lower Paranà from about the former Guairá falls, Uruguay and the state of Rio Grande do Sul in Brazil.

References

CASCIOTTA, J.R., S.E. GÓMEZ & N.I. TORESANNI. 200. Gymnogeophagus che, una nueva especies de la familia Cichlidae de la cuenca del río Paraná (Perciformes, Labroidei). Revista del Museo argentino de Ciencias Naturales, Nueva série, 2: 53-59.
de MIRANDA RIBEIRO, A. 1918. Dous generos e tres especies novas de peixes brasileiros determinados nas collecções do Museu Paulista. Revista do Museu Paulista, 10: 785-791.
REIS, R.E. & L.R. MALABARBA. 1988. Revision of the neotropical cichlid genus Gymnogeophagus Ribeiro, 1918, with descriptions of two new species. Revista brasileira de Zoologia, 4: 259-305.
REIS, R.E., L.R. MALABARBA & C.S. PAVANELLI. 1992. Gymnogeophagus setequedas, a new cichlid species (Teleostei: Labroidei) from middle Rio Paraná system, Brazil and Paraguay. Ichthyological Exploration of Freshwaters, 3: 265-272.