Friday, January 20, 2017

[PaleoIchthyology • 2017] Scleropages sinensis • First Complete Fossil Scleropages (Osteoglossomorpha) from the early Eocene, Hubei, China

Scleropages sinensis 
Zhang & Wilson, 2017
A new species of osteoglossid fish, Scleropages sinensis sp. nov., is described from the Early Eocene Xiwanpu Formation in Hunan and the Yangxi Formation in Hubei, China. The new species was attributed to Scleropages, an extant genus of Osteoglossidae, because it very closely resembles the genus in skull bones, caudal skeleton, the shape and position of fins, and reticulate scales. The new fish is very similar to extant Scleropages except: the nasals do not appear to be ornamented; the sensory pore in the antorbital is large; the posterior infraorbitals are not quite covering the dorsal limb of the preopercle; the posteroventral angle of the preopercle is produced to point; the posteroventral margin of the opercle is concave and the ventral end of the bone is produced to a point; the pectoral fin is very long and extends well behind the beginning of the pelvic fin; the vertebral count is about 46–48; the parapophyses are shorter and the upper and lower caudal rays are nearly as long as the inner rays. The new fish is closer to its Asian neighbor, S. formosus, than to its southern relative, S. leichardti. Scleropages formosus inhabits natural lakes, swamps, flooded forests, and slowly moving, deep parts of rivers with overhanging vegetative cover. It is a carnivorous fish and its food consists mainly of insects, fishes, worms, small amphibians, small mammals, and even birds. S. sinensis may live in the same natural environment and have a similar diet except for the largest items. Sexual dimorphism may exist in S. sinensis. The presumed male has a slimmer and shallower body, a relatively larger head, and a deeper mouth cleft. The discovery of Scleropages sinensis sp. nov. dates the divergence of Scleropages and Osteoglossum to no later than the Early Eocene.

 Key words: Hunan, Hubei, China; Early Eocene; Xiawanpu Formation; Yangxi Formation; Osteoglossidae

Systematic paleontology
Teleostei Müller, 1846
Osteoglossomorpha Greenwood et al., 1966
Osteoglossidae Bonaparte, 1832
 Scleropages Günther, 1864

Scleropages sinensis sp. nov.

Holotype: IVPP V 13672.2, a complete skeleton.
Referred specimens: IVPP V 12749.1–8, V 12750, V 13672.1, 3.

Locality and horizon: Specimens V 13672.1–3 and V 12750 are from Songzi County, Hubei Province, China; Yangxi Formation, Lower Eocene. Specimens V 12749.1–8 are from Xiangxiang, Hunan Province, China; Xiawanpu Formation, Eocene.

Etymology: The specific name refers to China where the specimens were found.

 Jiang-Yong Zhang and Mark V H Wilson. 2017. First Complete Fossil Scleropages (Osteoglossomorpha).  Vertebrata PalAsiatica. 55(1); 1–23

No comments:

Post a Comment