|Other Abstract||Multivariate morphometrics (Principal Component Analysis, PCA) was employed to investigate the distinctness of species of the barbine cyprinid genus Onychostoma Günther, 1896. The PCA was performed for 19 measurements among the problematic species or subspecies in the genus.Based on above results, the validity of these species or subspecies is evaluated. Interspecific relationships of 12 species of Onychostoma sensu lato were reconstructed based on cladistics methodology and morphological data. 7 species of Acossocheilus, Hypsibarbus, Poropuntius, and Spinibarbus were chosen as outgroups. A total of 98 variable osteological and external anatomical characters was observed and described. The data matrix is subjective to the parsimony analysis using the Hennig 86 software in Winclada 1.00 08. The following conclusions and hypotheses were reached:
1 A total of 18 valid species of Onychostoma sensu lato are here recognized and subdivided into three groups based on the mouth opening width and postlabial groove length. The narrow mouth-opening (type I) group is composed of those species with small mouth opening which width being less than the corresponding head width, and a long post-labial groove extending along about two-thirds of the side of the lower jaw, including O. lini, O. barbata; moderate mouth-opening (type II) group is composed of those species with mordetat mouth opening which width being equal to or slightly less than the corresponding head width, and a short post-labial groove that extends along around half of the side of the lower jaw, including O. ovale, O. rara, O. brevis, O. fangi, O. elongatum, O. intermedium, O. daduensis, O. simum, O. angististomata, O. fusiforme, O. meridonale, O. macrolepis; and wide mouth-opening (type III) group is composed of those species with wider mouth opening which width being greater than the corresponding width of the head, and a short post-labial groove restricted only to the side of the lower jaw, including O. lepturus, O. gerlachi, O. barbatula and O. alticorpus.
2 Onychostoma intermedium is here described as a new species from the Qiupu He, a tributary of the lower Yangtze River drainage at Shitai County, South Anhui Province, southern China.
Onychostoma intermedium, sp. nov
Holotype IHB 83IX2146, 145.7 mm SL, Qiupu He, a tributary on the southern bank of the lower Yangtze River, in Shitai County, southern Anhui Province, South China.
Paratypes IHB 83IX2144-5, 83IX2147-8, 4 specimens, 127.9-138.1 mm SL, other data same as holotype.
Diagnosis This new species with O. fusiforme and O. meridionale, has a longitudinal dark brown stripe extending along the lateral line on each side of the body, which can distinguish them from all other congeners of the moderate-mouth group. It differs from both in the presence or absence of two pairs of barbels in adults, from O. fusiforme in the body depth, thickness of the caudal peduncle, and positions of pelvic and anal fins, and from O. meridionale in the structure of the last simple dorsal-fin ray.
All type specimens are kept in the Freshwater Fish Museum of the Institute of Hydrobiology, Chinese Acadamy of Sciences, Wuhan, Hubei Province.
3 The subspecific status of O. o. ovale and O. o. rhomboids is not warranted based on the principal component analysis and covariate analysis.
4 The discovery of O. fusiforme in the Lancang Jiang drainage of China is the new record of its known distribution.
5 Three Vietnamese species, i.e O. thachaensis, O. yeni and O. babeensis. are affirmed to be junior synonyms of O. gerlachi.
6 Onychostoma sensu lato, as currently defined, is not a monophyletic, but polyphyletic group.
7 Onychostoma sensu strict, as here defined, is a monophyletic group and it can be subdivided into two subgenera. The subgenus Scaphesthes is composed of those species having a wide mouth-opening and Onychostoma includes those species with a moderate mouth-opening except for O. macrolepis.
8 The sister group of Onychostoma s. str. is the one represented by the barred species of Acrossocheilus except for A. monticola and likely A. clivosius.
9 Onychostoma lini and O. barbata should be assigned to their own generic rank, so is O. macrolepis.|