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Reversal and ambicoloration in two flounder species (Paralichthyidae, Pleuronectiformes)

L

UIZ

C O N S T A N T I N O D

AS

ILV

A J U N I O R

1, 2

,

A M A N D

AC

. DE

A N D R

A

D E 1 ,

M A G D A F . D E A N D R A D E - T U B I N O 1 , M A R C E L O V I A N N A 1

1 Laboratório de Biologia e Tecnologia Pesqueira, Avenida Prof. Rodolfo P. Rocco, 211 – Prédio do CCS – Bloco A – Sala A0-54 – Ilha do Fundão – Cidade Universitária – Rio de Janeiro – RJ – CEP: 21949-900. 2 E-mail: lconstantino@gmail.com

Abstract. One reversed Citharichthys macrops Dresel, 1885 and two ambicolored Paralichthys isosceles Jordan, 1891 specimens were caught in Guanabara Bay and Ilha Grande Bay, respectively. The prior is the first record of reversal for the genus in the Southwestern Atlantic Ocean and the first for the species in the world, whereas the latter are the first record for the species in Brazil. In both cases, the abnormal

specimens are meristically and morphometrically similar to the normal individuals.

Key words: Guanabara Bay, Ilha Grande Bay, Rio de Janeiro, Demersal Fisheries.

Resumo. Reversão e anficoloração em duas espécies de linguados

(Paralichthyidae,

Pleuronectiformes) Um espécime reverso de Citharichthys macrops Dresel, 1885 e dois espécimes anficoloridos de Paralichthys isosceles Jordan, 1891 foram capturados na Baía de Guanabara e Baía da Ilha Grande, respectivamente. O indivíduo reverso é o primeiro registro do gênero no Atlântico Sudoeste e o primeiro da espécie no mundo. Os anficoloridos são os primeiros registros deste caso no Brasil. Em ambos os casos, os espécimes anômalos são, merística e morfometricamente, similares aos indivíduos normais das espécies.

Palavras Chave: Baía de Guanabara, Baía da Ilha Grande, Rio de Janeiro, Pesca Demersal.

Among other features, Pleuronectiformes is considered a monophyletical order based on the ontogenetic migration of one of the eyes to the opposite side of the body. Due to their particular development, flounders typically have an assimetrical external coloration, pigmented on the ocular side and unpigmented on the blind (Hensley 1997). According to the orientation of the eye migration, they may be dextral (eyes and colour on the right side) or sinistral (eyes and color on the left side) (Díaz de Astarloa 1997).

Occasionally, individuals display eyes and pigmentation on the expected blind and unpigmented side, a phenomenon called reversal (Díaz de Astarloa 1997). Other malformations reported for flounders include pigmentation defects, such as ambicoloration. This is a widely reported phenomenon for flatfish (e. g. Hussakof 1914, Gudger 1935, Gudger & Firth 1935, Gudger 1936, Díaz de Astarloa 1994, Díaz de Astarloa 1998,

Chaves et al. 2002, Carnikián et al. 2006, Macieira et al. 2006) and occurs when the blind side, usually lacking pigmentation, is ontogenetically colored, characterized by the presence of similar pattern elements (including ocelli) on both sides of the body (Bolker et al. 2005).

The specimens analyzed in this paper, one reversed Citharichthys macrops Dresel, 1885 and two ambicolored Paralichthys isosceles Jordan, 1891, were caught in regular surveys, employing shrimping boats and using trawl nets, in Guanabara Bay and Ilha Grande Bay, respectively, both in Rio de Janeiro state.

Citharichthys macrops is one of the five Citharichthys species known in Brazilian waters. It can be easily recognized by its spotted pattern on the caudal fin. Such spots (three or four) remain visible even after fixation and conservation. This marine species is usually found in shallow waters, less than 40 m deep, away from bays and estuaries. Its

Pan-American Journal of Aquatic Sciences (2007) 2 (1): 23-26

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