Synaptura

Abstract: Fishes constitute slightly more than one half of the total number of approximately 54,711 recognized living vertebrate species of the world. Flatfishes represent an interesting and diverse order of marine, estuarine and to a lesser extent, freshwater euteleostean fishes. They are common species in most marine fish assemblages right from the poles to the tropics. Flatfishes captured in tropical fisheries are often not identified even to genus or family level rather, much of the catch is merely identified as “Pleuronectiformes”; 54-80% of the total landings of tropical flatfishes consist of unidentified species. For flatfishes inhabiting tropical seas, despite recent progress, considerable diversity is still being discovered and the taxonomy of many tropical flatfishes remains especially problematic. Failure to identify species, and erroneous species identifications, still represent serious impediments to collection of meaningful data for many of these smaller species. Work on Indian flatfishes has been scattered over the time period and ample scope exists for a study on the diversity of the group. Based on the present collections from different parts of South India and Andaman Islands during the period 2004 - 2010, 63 species of flatfishes belonging to 8 families and 26 genera have been collected. The most speciose family was Soleidae with 9 genera and 17 species, followed by Bothidae with 9 genera and 14 species and Cynoglossidae with 2 genera and 13 species. Family Bothidae had representations from deep sea. New distributional records were Aserraggodes kobensis and Brachirus annularis for the Indian waters. Psettodes erumei a major resource in the flatfish fishery has virtually been absent in the landings except for stray numbers in large trawlers off Mangalore. The study points out the decline of the resource off South India. This calls for immediate steps to device steps to protect and preserve this species. New emerging resources in the fishery are Synaptura commersoniana in the estuarine landings off Kochi. Occurrence of Pardachirus pavoninus, Heteromycteris oculus and Paraplagusia bilineata in the ‘rollermadi’ landings at Pamban point to the existence of these ornamental varieties in the Gulf of Mannar.

Abstract: Dagetichthys marginatus (formerly Synaptura marginata ) larvae were laboratory-reared from wild caught adult broodstock as part of an aquaculture research project in temperate South Africa. A larval description for the species is provided in this paper. This work also represents the first larval description for the genus Dagetichthys , which is represented by five species, three of which occur in the western Indian Ocean. Larval development in D. marginatus is typical of Soleidae. Dagetichthys marginatus larvae are heavily pigmented, with four characteristic melanophore “blotches” on the finfold. These larvae are easily distinguished from other soleid larvae commonly encountered in temperate South Africa based on the large size at flexion (5-7.06 mm BL) and the heavily pigmented body. Laboratory-reared postflexion larvae in this study showed similar meristic counts to those of wild caught adult fish. Despite the common occurrence of mature adults of this species in shallow marine waters off temperate South Africa, larvae are absent from nearshore ichthyoplankton catches. As yet, the spawning strategy of the species is unknown.

Abstract: Dagetichthys lakdoensis is a small freshwater flatfish (Pleuronectiformes) inhabiting the drainage basin of the Benoue river in Cameroon, more than 1300 km inland from the Atlantic Ocean. The familial affinities (Achiridae or Soleidae) of this genus have never been clearly established. A morphological and osteological study of radiographs and of a cleared and stained specimen resulted in the finding of the previously determined autapomorphies of the family Soleidae. In addition, we have found two derived characters (presence of 1 or 2 rays on the pelvic fins and an elongated urohyal without a ventral branch) that unite Dagetichthys and all the species associated with the genus Synaptura. Because the monophyletic status of the latter genus was found to be dubious, we cannot, at this point, determine if Dagetichthys is the sister-group of the genus Synaptura or the sister-group of one (or several) species within the genus. We discuss the fact that, from a biogeographical standpoint, the latter possibility appears more plausible.

Abstract: The objective of this study was to taxonomically revise the 41 nominal species found within the Brachirus species complex (Order Pleuronectiformes; Family Soleidae). This complex is recognizable by a combination of characters: the structure of the supracranial portion of the dorsal fin which lack pterigiophores with their proximal ends directly over the cranium, by the joined dorsal, anal and caudal fins, and by the anterior tip of the dorsal fin almost reaching the upper jaw. This revision is based on the morphological and meristic examination of 34 type and 717 non-type specimens for all available nominal species. The type material was examined for twenty species. The remaining species were assessed from the original type description. It was found that the Brachirus species complex is made up of four genera including 19 valid species: Brachirus (14), Achiroides (1), Dexillus (3), and Paradicula (1). Eight of the nominal species do not belong to the Brachirus species complex and have been removed from the scope of this study. Achiroides, characterized by the rudimentary pectoral fins, contains a single valid species, A. melanorhynchus (Bleeker 1851) and three synonyms (Synaptura aenea Smith 1931, Anisochirus harmandi Sauvage 1878, and Plagusia leucorhynchos Bleeker 1851). Dexillus , characterized by the close proximity of the eyes, contains three valid species: D. macrolepis (Bleeker 1858), D. megalepidoura (Fowler 1934), and D. muelleri (Steindachner 1879). D. muelleri is a senior synonym of the nominal species Synaptura arafurensis Gunther 1880. Paradicula, unique in having the gill openings restricted to the base of the pectoral fins, contains a single valid species, P. setifer Paradice & Whitley 1927. The remaining Brachirus species cannot yet be defined as being monophyletic. Brachirus contains 14 valid species: B. aspilos (Bleeker 1852) (synonyms: Synaptura heterolepis Bleeker 1856, S. marmorata Bleeker 1853, and S. sorsongonensis Evermann & Seale 1907), B. sundaicus (synonyms: Bleeker 1870 – 75) (Synaptura cinerea De Vis 1883 and S. nigra MacLeay,1880), B. selheimi (Macleay 1882) (synonyms: B. salinarum Ogilby 1910, and Synaptura villosus Weber 1907), B. foliacea (Gunther 1862) (synonym: Synaptura filamentosa Sauvage 1878), B. siamensis (Sauvage 1878) (synonyms: Synaptura krempfi Durand 1940 and Chabanaudetta smithi Joglekar 1971), B. breviceps Ogilby 1910, B. cinerascens (Gunther 1862), B. fitzroiensis (De Vis 1882), B. orientalis (Bloch & Schneider 1801), B. pan (Hamilton 1822), B. panoides (Bleeker 1851), B. dicholepis Peters 1877, B. swinhonis Steindachner 1867, and B. canus Gray 1854. An identification key of valid species belonging to the Brachirus species complex is provided.