Achirus

Abstract: Three cases of color abnormalities and one of morphological aberration in flatfishes of the genus Achirus are described from the Piraque-Acu River estuary, Espirito Santo, Brazil. One specimen of A. declivis has 75% of the blind side with coloration like that of the ocular side. Another specimen of the same species is strongly hypomelanistic. A third specimen has incomplete eye rotation and a hooked dorsal fin. An ambicolored A. lineatus is also described.

Abstract: Eustomias achirus, previously known only from the holotype and a few specimens of questionable identity, is unique in that it lacks pectoral-fin rays but has a short, pigmented barbel with three prominent branches similar to the barbels of species with two pectoral-fin rays in the subgenus Dinematochirus. Examination of over 70 previously unreported specimens without pectoral-fin rays and with structurally similar barbels revealed many different forms occurring in all three major oceans. Five of these are described as new species: E. aequatorialis, E. intermedius, and E. insularum from the Atlantic and E. tomentosis and E. woollardi from the Pacific. Several other Indo-Pacific specimens of uncertain status are also reported. All species and forms of the group are distinguished from other members of Dinematochirus by a unique combination of barbel characters.

Abstract: The genus Achirus is made up of demersal fish that have a close relationship with the substrate and exhibit peculiar aspects during their larval stage. The aim of the present study was to determine whether the abundance of Achirus larvae differed among a set of habitats in the estuary of the Formoso River in the State of Pernambuco (north-eastern Brazil). Sampling was performed monthly between April 2009 and March 2010, and comprised horizontal hauls with plankton net during the day and night in mangrove, beach and reef habitats. Fish larvae were sorted, identified, measured and larval stage recorded. Density and body length values were used in a non-parametric analysis of variance for the determination of variations between seasons, habitats and diel periods. A total of 204 larvae were collected, with an average density of 2.1 larvae.100 m−3. Density was greater in the nocturnal samplings, with no differences found between habitats. The larvae occurred in the yolk-sac to post-flexion stage, with pre-flexion the most abundant stage (78%). Size segregation was observed. Larger larvae were captured at night and in the mangrove. The smallest larvae were caught on the reef, with length increasing toward the mangrove. The results indicate that Achirus larvae come from deeper regions near reefs, where spawning probably occurs, and perform ontogenetic migration towards the shallow waters of mangrove, where they settle.

Abstract: RESUMEN. Se comunican los primeros registros de los Pleuronectiformes Achirus klunzingeri (Soleidae), Etropusectenes y Bothus constellatus (Bothidae) y Symphurus elongatus (Cynoglossidae) en aguas de chilenas. Las caracteris-ticas morfologicas de los especimenes estudiados se confrontan con descripciones previas. Se discute su distribucionen el Pacifico sur oriental y aquella del orden en aguas chilenas. Palabras claves: Pleuronectiformes, nuevos registros, Etropus ectenes , Bothus constellatus , Achirus klunzingeri , Symphurus elongatus , norte de Chile. First records of Etropus ectenes Jordan, 1889, Bothus constellatus Jordan & Goss,1889, Achirus klunzingeri (Steindachner, 1880) and Symphurus elongatus (Gunther,1868) (Pisces: Pleuronectiformes) in Chile, with comments on the distribution of theChilean flounders ABSTRACT. The first records of the Pleuronectiformes Achirus klunzingeri (Soleidae), Etropus ectenes and Bothusconstellatus (Bothidae), and Symphurus elongatus (Cynoglossidae) in chilean waters are reported. The morphologicalcharacteristics of the studied specimens are compared with previous descriptions. Their distribution in the SoutheasternPacific and that of the order in Chilean waters are discussed.