| The subfamily Acheilognathinae, belonging to Cyprinidae, Cypriniformes, mainly occur in the East and Southeast Asia with the exception of Rhodeus amarus and Rhodeus colchicus, which occur in Europe. In the present study, after carefully examining some specimens of the subfamily Acheilognathinae, including newly collected and collection of the Institute of Hydrobiology, Chinese Academy of Science (IHCAS), we reviewed taxonomy of this subfamily and analyzed its molecular phylogenetic relationships. The main results as follows:1. Based on the examinations of 515 specimens and review of the references, we supported that the subfamily can be grouped into three genera, Acheilognathus, Rhodeus and Tanakia, which include 37,12 and 5 valid species respectively. The major diagnostic morphological characters, distributions and synonyms of each species were revised.2. A new species of bitterlings, Acheilognathus striatus sp. nov., is described on the basis of 57 specimens collected from lower reaches of the Yangtze River in Jiangxi Province, China. It can be distinguished from all congeners by the following combined characters:a pair of barbels rather long, slightly longer than half of eye diameter; dorsal fin with three simple and 8-9 branched fin rays, anal fin with three simple and 7-8 branched fin rays; a black longitudinal stripe on body from the base of caudal peduncle, distinctly reaching anteriorly to the vertical line from the origin of dorsal fin, broader in males than in females; a scale distance between the longitudinal stripe and lateral line below the origin of dorsal fin; dorsal and anal fin margined with black band in male.3. A new species of the bitterling genus Acheilognathus, Acheilognathus changtingensis sp. nov., was recently discovered from Changting County in Hanjiang River, Fujian Province, Southeastern China. It can be diagnosed by the following combination of characters:dorsal fin with three simple and 15 (casually 14) branched fin rays, anal fin with three simple and 12 (casually 11) branched fin rays; dorsal fin pale and anal fin slightly pale relatively; white spots on anal fin rays forming a transverse band, and anal fin margined with white band in male. The unique characters are the many dispersed black spots on the dorsal, anal, pelvic, caudal fins, and also on the head. Using mitochondrial cytochrome b gene as a molecular marker, we reconstructed the phylogenetic trees of A. changtingensis and its closely related species to analyze its phylogenetic position. The results showed that A. changtingensis sp. nov and Acheilognathus macropterus were sister species, and they separated about 5.85 mya resulted by geographical isolation.4. Based on the complete cytochrome b gene sequence, we constructed the phylogenetic tree of 29 Acheilognathus barbatulus and Acheilognathus peihoensis group. The phylogenetic tree suggested that samples with barbels and those without barbels were intermingled and they didn’t form their own monophyly respectively. There was also no distinctive difference in morphological characters among them. So we considered it was invalid to identify the samples without barbels as A. peihoensis. Acheilognathus peihoensis should be considered as a junior synonym of A. barbatulus.5. Using cyt b gene and RAG 2 gene as molecular markers, we estimated the phylogenetic relationship of the subfamily Acheilognathinae with MP, NJ and BI methods. All the analyses confirmed the monophyly of the genus Acheilognathus and Rhodeus. But different genes and different methods had different results about the genus Tanakia.6. The structure of d-loop of the subfamily Acheilognathinae was analyzed and its phylogenetic implication discussed. The d-loop region consists of three domains, including Extended termination associated sequence (ETAS) domain, Central conserved domain (CD) and Conserved sequence block (CSB) domain. Some conserved blocks were identified and their general sequences were given. In ETAS, ETAS was identified; in the CD, three conserved blocks, CSB-D, CSB-E and CSB-F were identified; in the CSB, CSB-1, CSB-2 and CSB-3 were successfully identified. Sequence varioations of the D-loop region are due to the presence of a variable number of repeats and long inserted sequences in the ETAS. We suggested that the mechanism responsible for repeated sequences and inserted sequences is slipped strand mispairing, unidirectional replications and transposition. The phylogenetic MP and BI trees of the subfamily Acheilognathinae were derived from CD and CSB domains. The topology indicated Acheilognathus, Rhodeus and Tanakia all formed monophyly, which showed the d-loop sequence had phylogenetic meaning. Due to the low bootstrap values and Bayesian posterior probabilities, we thought the phylogenetic implications of the d-loop in the subfamily Acheilognathinae was limited. Great cautious should be taken whileusing d-loop as a molecular marker for phylogenetic analysis in this group. |
PDF Full Text Request