Thursday, December 13, 2018

[Ichthyology • 2018] Gymnogeophagus peliochelynion • A New Mouth Brooder Species of Gymnogeophagus with Hypertrophied Lips (Cichliformes: Cichlidae) from A Tributary of the río Uruguay


Gymnogeophagus peliochelynion
Turcati, Serra-Alanis & Malabarba, 2018


ABSTRACT
A new mouth breeder species of Gymnogeophagus is described from a tributary of the río Uruguay. It is distinguished from most species of the genus by the presence of hypertrophied lips, and from G. labiatus and G. pseudolabiatus by the color pattern. The presence of successive allopatric species of the Gymnogeophagus gymnogenys clade inhabiting the tributaries of the río Uruguay is discussed.

Keywords: Distribution; Endemism; Gymnogeophagus gymnogenys clade; New species; Río Uruguay

Fig. 2 Head of Gymnogeophagus peliochelynion (first column), G. pseudolabiatus (second column) and G. mekinos (third column) showing the entirely black hump in males in G. peliochelynion (vs. yellow with black margin), and upper lip not folded dorsally over anterior margin of snout (vs. upper lip folded dorsally in G. pseudolabiatus and undeveloped in G. mekinos).
G. peliochelynion from top to bottom, paratype, ZVC-P 13210, paratype, 76.3 mm SL; ZVC-P 7016, 89.9 mm SL; ZVC-P 13057, 90.2 mm SL.
 G. pseudolabiatus from top to bottom, paratype, UFRGS 7754, 102.0 mm SL; MHNM 4010, 88.8 mm SL; MHNM 4010, 95.3 mm SL.
G. mekinos from top to bottom, MHNM 3511, 105.1 mm SL; MHNM 3511, 97.2 mm SL; MHNM 4009, 121.3 mm SL. 

Fig. 4 Gymnogeophagus peliochelynion: top, holotype, male, ZVC-P 12493, 101.9 SL; bottom, paratype, female, UFRGS 8076, 77.2 SL. Both from arroyo de las Tunas on road 31, tributary of río Arapey Grande, Salto, Uruguay. Photographs taken just after collection and fixation in formalin.

Gymnogeophagus peliochelynion, new species

Diagnosis. The new species can be distinguished from the species of the Gymnogeophagus rhabdotus group and from G. balzanii by the shape of the caudal peduncle longer than deep (vs. deeper than long). It is distinguished from all congeners, except G. labiatus and G. pseudolabiatus, by the possession of thick lips. It differs from G. labiatus and G. lacustris by the lack of an oblique bar from the eye to the dorsal-fin origin (vs. oblique bar present), and by the color pattern of the caudal, dorsal and anal fins with dots (vs. caudal fin and posterior portion of anal fin with longitudinal hyaline stripes). It differs from G. pseudolabiatus and G. mekinos by the hump entirely black in males (Fig. 2; vs. yellow with black margin), and upper lip not folded dorsally over anterior margin of snout (vs. upper lip folded dorsally, usually with a well-developed medial lobe dorsally projected in G. pseudolabiatus).
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Ecological notes. The new species was collected in rivers with clear water, usually with rocky or muddy bottom and little vegetation.

Etymology. The name peliochelynion is from the Greek pelios, meaning black and blue, and chelyne, meaning lip, in reference to the color of the lips of the new species. A name in apposition.

Fig. 5 Gymnogeophagus peliochelynion: above, paratype, male, ZVC-P 13210, paratype, 76.3 mm SL, río Arapey, Colonia Lavalleja, Paso Elías, Salto, Uruguay; below, female, ZVC-P 13057, 65.3 mm SL, Arroyo Sopas, Paso del Cementerio, Salto, Uruguay. Photographs of live specimens.


Andréia Turcati, Wilson Sebastián Serra-Alanis and Luiz R. Malabarba. 2018. A New Mouth Brooder Species of Gymnogeophagus with Hypertrophied Lips (Cichliformes: Cichlidae). Neotrop. ichthyol. 16(4). DOI: 10.1590/1982-0224-20180118 

RESUMEN: Una nueva especie incubadora bucal de Gymnogeophagus es descripta de un tributario del Río Uruguay. Se distingue de la mayoría de las especies del género por la presencia de labios hipertrofiados, y de G. labiatus y G. pseudolabiatus por su patrón de coloración. Se discute la presencia de sucesivas especies alopátricas del clado Gymnogeophagus gymnogenys habitando los tributarios del Río Uruguay.

Palabras Clave: Distribución; Endemismo; Clado Gymnogeophagus gymnogenys; Especie nueva; Río Uruguay