Wednesday, November 30, 2016

[Ichthyology • 2016] Oreonectes daqikongensis • A New Blind Species of the Cave Genus Oreonectes (Balitoridae: Nemacheilinae) from Guizhou, China

 Oreonectes daqikongensis  
Deng, Wen, Xiao & Zhou, 2016 

This study aimed to describe a new specimen of cavefish collected from a karst cave in the Daqikong area of Libo County, Guizhou. Twenty-six cavefish specimens were collected and identified as a new species of Balitoridae: Nemacheilinae, and named Oreonectes daqikongensis sp. n. A genetic analysis was performed and showed that its genetic distances from Oreonectes shuilongensis and Oreonectes platycephalus are higher than intraspecific distances. Discovery of this species will be helpful to understand the distribution of Oreonectes.

Keywords: Cavefish, Libo, new species, Oreonectes daqikongensis sp. n.

Figure 1. a Holotype of  Oreonectes daqikongensis sp. n. NO.CNGZNU20110128002.
 A living Oreonectes daqikongensis sp. n.

Diagnosis: The species has a large head, and the width of the head is larger than its depth. The frontal torso is nearly cylindrical, the backend gradually compresses, and the head is slightly flattened. There is a short distance between the anterior and posterior nostrils, and the anterior nostril forms a short and tubular structure, which is truncated backward. The pectoral fin extends backward to or beyond the starting point of the pelvic fin. The body is naked. The eyes are completely degraded; and eye socket was filled in fat tissue and without any outside remnant indicating their presence. The superior and inferior caudal peduncles have well-developed soft finfolds. No carneous fin flaps are present in the pelvic fin axilla. The air bladder is wrapped in a bony capsule, and the posterior chamber of the air bladder is developed into a membranous chamber, which is separated from the abdominal cavity and connected to the anterior chamber by a short duct. The whole body is white and transparent, when they are alive, they look a little red because the blood inside, and is unlikely to become black when it is fed in sunlight for a long term.

Habitat:  This species was found only in the Daqikong scenic area. The opening of the cave was halfway up the mountain, and the distance from the opening to the pool was about 15–20 m. The cave got no sunshine because of the twisty pathway. A large number of Hipposideros armiger lived in the cave and a thick layer of bat dung was found on the ground. Groundwater extended into the cave, and the water rushed outside the cave in the case of heavy rain. So far, no other fish, shrimps, or aquatic animals were found in the cave. The subterranean river belonged to the Dagou river system, and was the main river of the Libo County, which runs through the whole county, enters Guangxi from the Laocun Xiang, and was the major tributary of the Duliu River system (Figure 2).

 Huaiqing Deng, Huamei Wen, Ning Xiao and Jiang Zhou. 2016. A New Blind Species of the Cave Genus Oreonectes from Guizhou, China (Nemacheilinae).
  ZooKeys. 637: 47-59. DOI: 10.3897/zookeys.637.10202