| [Objectives] According to Li’s “Fauna Sinica, Osteichthyes, Pleuronectiformes” in 1995, the five species with specimen of genus Arnoglossus in Bothidae were records along the coastal waters of the Chinese mainland, including the Arnoglossus tapeinosoma, A. tenuis, A. polyspilus, A. Scapha and A. japonicus. Weber et al. listed Arnoglossus macrolophus Alcock, 1889 as synonym of Platophrys (Arnoglossus) tapeinosoma Bleeker, 1866 (currently Arnoglossus tapeinosomus) in 1929, this opinion has been accepted by many authors at home and abroad. In 1996, Arai et al. re-examined the holotype of A. tapeinosoma, and checked the specimens of A. tapeinosoma supposedly conspecific by Weber et al. and other researchers. They pointed out that all these specimens misidentificated as A. tapeinosomus should be A. macrolophus; A. macrolophus was affirmed to be the valid name. During this study from 2008 to 2021, off the coast of mainland China, samples resembling A. macrolophus and A. tapeinosomus were found, in order to correctly identify the specimens, the morphology and molecular barcodes were studied in this study. [Methods] The morphological features of representative samples were compared with that of type specimen and related research data of A. tapeinosoma and A. macrolophus. [Results] The results showed that the eight meristic features and 20 proportional values in our samples were the same, continuous, inclusive or slightly differece with those of A. macrolophus (Table 1). In particular, all three distinguishing features of elongated dorsal fin rays, black spots on the end of dorsal and anal fins, and developed prevomer are consistent, but there are many differences with the characteristics of A. tapeinosomus. Thus, the samples in this study were identified as A. macrolophus. The genetic distance of the COI sequence obtained in this study (GenBank number: MZ086865) was 12% between one of A. macrolophus collected from Taiwan, China, and zero between three others of A. tapeinosomus collected from the South China Sea and Vietnam downloaded on GenBank. Therefore, these three samples from the South China Sea and Vietnam were misidentified as A. tapeinosomus and should be A. macrolophus, but the species of A. macrolophus from Taiwan, China cannot be determined without specific morphological information of specimen. [Conclusion] This species of A. macrolophus was found for the first time along the coastal waters of Chinese mainland, thus a new record species. Accordingly, A. macrolophus is redescribed herein based on the morphological data of type specimen, the results of ours and previous studies. The main diagnostic characters of this species are: the first 1-6 dorsal fin rays of the male prolonged into long filaments, a large dark brown spot at the junction of the straight and curved lateral line, a large dark spot on distal part of pectoral, two small black spots on the straight of the lateral line, a slightly larger black spot on the of the posterior dorsal and anal fin bases, and a row of about 5-6 and 3-4 pale black spots scattered near the margins of dorsal and ventral fins, respectively. |
