L. C. DA SILVA JR. ET AL.
distribution ranges from North Carolina (USA) to Santa Catarina (Brazil) (Figueiredo & Menezes 2000).
Paralichthys isosceles is one of the five Paralichthys species known in Brazilian waters. The species is easily recognized due to three conspicuous dark ocelli in the posterior half of the body, ctenoid scales on the blind side and a small freckle between the third and fourth rays of the left pelvic fin. Due to their medium to large size and wide distribution, from Southeastern Brazil to Patagonia (Argentina), Paralichthys is the only genus of Pleuronectiformes in Brazil with commercially important species (Figueiredo & Menezes 2000).
Ten sinistral C. macrops individuals (Figure 1a) as well as the reversed specimen (Figure 1b) (Total Length, TL = 133 mm, Standard Length, SL = 107.8 mm and Total Weight, TW = 27.2 g) were caught in Guanabara Bay (22°55'36.8" S; 43°07'48.1" W) in February 2006, in waters between 7.5 and 10.0 meters deep. These specimens were catalogued in the Museu de Zoologia, Universidade de São Paulo (MZUSP) under the
Figure 1. a) Typical Citharichthys macrops, MZUSP 91682; b) Reversed C. macrops, MZUSP 91681, both caught at Guanabara Bay, Rio de Janeiro state.
following registration numbers: MZUSP
(1 reversed specimen) (10 normal specimens).
The reversed C. macrops had
number of dorsal and anal fin rays than the mean number of rays counted for the typical specimens (Table I). However, Figueiredo & Menezes (2000) report a number of dorsal fin rays ranging from 74 to 85 and the anal fin rays from 56 to 64. The morphometrical characteristics are also in accordance with the information in the literature (Figueiredo & Menezes 2000; Munroe 2002). Therefore, externally, the dextral specimen is a mirror image of the normal sinistral C. macrops.
in January 2006 in waters about 60.0 meters deep,
outside Ilha 44º12’26.5” W).
The first was almost fully ambicolored, with lack of pigmentation restricted to the cephalic region, while the second showed pigmentation only on the posterior portion of the body. Similar patterns were described for P. orbignyanus on the Uruguayan coast (Carnikián et al. 2006). All specimens were catalogued in MZUSP under the following registration numbers: MZUSP 91683 (2 ambicolored specimens) and MZUSP 91684 (11 normal specimens).
Reversal appears to be rare in Citharichthys flounders, with only two previous cases reported in the Northern Atlantic Ocean: C. spilopterus (Castillo-Rivera & Kobelkowsky 1992) and C. abbotti (Dawson 1969 apud Castillo-Rivera & Kobelkowsky op. cit.). However, some species in the sinistral Paralichthyidae family have a high reversal rate (Munroe 2002). For instance, up to 40% of individuals are reversed in Paralichthys californicus (Ginsburg 1952 apud Díaz de Astarloa 1997). The present study is the first record of reversal for the genus in the Southwestern Atlantic and the first for Citharichthys macrops.
Eleven normal individuals, as well as two ambicolored P. isosceles specimens (Figure 2) (TL = 124.0 and 263.0 mm , SL = 98.8 and 220.0 mm and TW = 14.7 and 184.3 g, respectively), were caught
Figure 2. A typical (above) and an ambicolored (below) Paralichthys isosceles, caught at Ilha Grande Bay, Rio de Janeiro state. Voucher numbers are MZUSP 91684 and MZUSP 91683, respectively.