Diet overlap among flatfish species in the southern North Sea

The diets of two non-commercial flatfish species (solenette Buglossidium luteum and scaldfish Arnoglossus laterna) and two commercial flatfish species (dab Limanda limanda and plaice Pleuronectes platessa) were compared in a study area in the German Bight (southern North Sea) to investigate prey-resource partitioning between these species. The diets of A. laterna and B. luteum mainly comprised crustaceans (harpacticoids, amphipods, cumaceans and decapods), whereas the diet of L. limanda and P. platessa consisted mainly of polychaetes. The Schoener index, calculated for different fish size classes between these flatfish species, showed a biologically significant diet overlap between small-sized L. limanda and P. platessa and B. luteum and A. laterna, using similar prey resources of smaller prey (e.g. amphipods, harpacticoids and juvenile bivalves). In contrast, with increasing body size, a change in the diet of L. limanda and P. platessa towards larger prey occurred (e.g. polychaetes and decapods), resulting in low diet overlap values with B. luteum and A. laterna. Due to these size-related differences in resource use, it is assumed that there is reduced interspecific competition for prey between larger L. limanda and P. platessa and both non-commercial flatfishes, probably facilitating resource partitioning within the same area. In contrast, smaller L. limanda and P. platessa may compete directly for the same prey resources with B. luteum and A. laterna. Furthermore, prey availability of most important prey items of the studied flatfishes was relatively low in the study area. Therefore, increasing abundances of B. luteum and A. laterna in the southern North Sea since the late 1980s, owing to fishing effects and climate change, might affect the population dynamics of L. limanda and P. platessa.     

Larvae of <Emphasis Type="Italic">Arnoglossus elongatus</Emphasis> (Pleuronectiformes: Bothidae) from northwestern Australia

Eleven postflexion larvae (9.1–23.9mm standard length: SL) of a bothid, Arnoglossus elongatus, from northwestern Australian waters were described. These specimens were characterized by vertebral numbers of 11–12+32–34=43–45, slender body, remarkably elongated second dorsal fin ray, and presence of melanophores on and slightly above midlateral line of body, plus on dorsal wall of abdominal cavity and air bladder (specimens >12.6mm SL), proximally on caudal fin rays (>16.5mm SL), and on pterygiophore zones of dorsal fin and anal fin (>23.8mm SL).     

中国大陆近海新记录种——长冠羊舌鲆（Arnoglossus macrolophus）

历史记录我国大陆羊舌鲆属（Arnoglossus）有5个物种,它们是长鳍羊舌鲆（A. tapeinosoma）、纤羊舌鲆（A.tenuis）、多斑羊舌鲆（A. polyspilus）、大羊舌鲆（A.scapha）和日本羊舌鲆（A.japonicus）。1929年Weber等将长冠羊舌鲆（Arnoglossus macrolophus Alcock,1889）列为长鳍羊舌鲆[Platophrys(Arnoglossus)tapeinosoma Bleeker,1866;目前为A. tapeinosomus]的同物异名,并被国内外许多学者所采纳。Arai等1996年重新检视了长鳍羊舌鲆的模式标本和Weber等的长鳍羊舌鲆,发现了Weber等的标本应为长冠羊舌鲆,确认了长冠羊舌鲆种的有效性。作者2008至2021年间在中国大陆近海采集到了一批拟似长鳍羊舌鲆和长冠羊舌鲆的标本,为了正确鉴定这些标本,本研究对其形态和分子条形码进行了研究,将我们所采集标本的形态特征与两种模式种以及前人的研究数据进行了比较。结果表明,本研究标本的8个可数性状和20个性状比例值与长冠羊舌鲆的数值为相同、连续、包含或略...     

A new species ofArnoglossus (Pleuronectiformes: Bothidae) from the southwestern coast of Australia

A new bothid flounder,Arnoglossus micrommatus, is described from the southwestern coast of Australia (off Albany, Western Australia). This species is distinguished from other species ofArnoglossus by combination of the following characters: gill-rakers serrated on posterior margin; upper jaw length 2.83–3.12 in head length (HL); upper eye diameter 4.17–5.51 in HL; scales in lateral line 52–62; vertebrae 11+28−29=3t-40.