Acaronia Myers

Synonymy

Acaronia Myers, 1940. Stanf. ichthyol. Bull. 1, p. 170 (nom. nov. pro Acaropsis Steindachner). — Feminine.
Acara (Acaropsis) Steindachner, 1875. Sber. k. Akad. Wiss. Wien Math.-natw. Cl. 71, p. 80 (type by monotypy Acara nassa Heckel; preoccupied by Acaropsis Moquin-Tandon, 1859, p. 296, Arachnida). — Feminine.

Acaronia nassa, NRM 28298, adult, freshly preserved, from Brazil, Amapá, Juminán, near Cunene village.
28 March 1994 (SOK 94-035). Photo: S.O. Kullander.

Diagnosis

Acaronia is distinguished by its large gape, correlating with long ascending premaxillary processes reaching beyond middle of orbit. The scales are large, 22 scales in the E1 row. Vertebrae few, 12+12. Flank lateral line tubes prominent, cephalic lateralis foramina wide (4 mandibular and 6 preopercular foramina). Lachrymal bone narrow, with four lateralis foramina. Infraorbital bones tubular, the second with a middle foramen. Two supraneurals.

Acaronia resembles Chaetobranchus externally, but have comparatively strong, not as numerous gill rakers (1-2 epibranchial, one in angle, and up to 13 cerato- and hypobranchial gill rakers).

Included species

Acaronia nassa (Heckel, 1840)

Acaronia vultuosa Kullander, 1989

Identification guide to species

Only two species are recognized, differing in colour pattern and gill arch structures; please refer to species diagnoses.

Etymology

Acaropsis — Acara, another cichlid genus, to which Acaronia nassa initially was referred, in its turn based on the Tupi-Guarani name for cichlids, acará; and the Greek suffix -opsis meaning like.
Acaronia — same as Acaronia, but with different ending, of unknown derivation.

Geographical distribution

Acaronia nassa is found in most of the Amazonian lowlands, including Bolivian Amazonia, and also in the State of Amapá in Brazil, and in Guyana, whereas A. vultuosa is found in the Orinoco basin and the upper Rio Negro. The geographic ranges of A. nassa and A. vultuosa overlap slightly along the upper Rio Negro, A. vultuosa descending to the Ilha Tamaquaré, where syntopic with A. nassa, and A. nassa ascending to the mouth of the Rio Marauiá. Nevertheless, the area of range overlap is very restricted relative to the range of each species.

References

HECKEL, J. 1840. Johann Natterer's neue Flussfische Brasilien's nach den Beobachtungen und Mittheilungen des Entdeckers beschrieben. (Erste Abtheilung, die Labroiden.) Annln wien. Mus. Natges. 2: 327-470.
KULLANDER, S.O. 1986. Cichlid fishes of the Amazon River drainage of Peru. Swedish Museum of Natural History, Stockholm, 431 pp.
KULLANDER, S.O. 1989. Description of a new Acaronia species from the Rio Orinoco and Rio Negro drainages. Zool. Scr. 18: 447-452.
MOQUIN-TANDON, A. [1859.] Éléments de zoologie médicale contenant la description détaillée des animaux utiles a la médecine et des espèces nuisibles a l'homme particuliérement des venimeuses et des parasites précédée de considérations générales sur l'organisation et sur la classification des animaux et d'un résumé sur l'histoire naturelle de l'homme. Paris, x+428 pp.
MYERS, G.S. 1940. Suppression of Acaropsis and Chalcinus, two preoccupied generic names of South American fresh-water fishes. Stanf. ichthyol. Bull. 1: 170.