New Species of Arowana (Osteoglossid Fish) Discovered from the Eocene of China
“The Asian arowana (Scleropages formosus), known as the dragon fish, is one of the most prized and expensive aquarium fishes in the world. Scleropages is an extant freshwater fish of Osteoglossidae with a transoceanic distribution in Southeast Asia and Australia. All previously Known fossil records of Scleropages are scales, otoliths and isolated fragments of bones, and the distribution of osteoglossids remains a zoogeographical enigma.
In a paper published in the latest issue of Vertebrata PalAsiatica, Dr. ZHANG Jiangyong, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, and Dr. Mark Wilson, Department of Biological Sciences, University of Alberta, reported a new species of osteoglossid fish, Scleropages sinensis sp. nov., from the Early Eocene Xiwanpu Formation in Hunan and the Yangxi Formation in Hubei, China. The discovery of Scleropages sinensis dates the divergence of Scleropages and Osteoglossum as at least old as the Early Eocene, which is a significant step toward solving this zoogeographical puzzle.
The body of the new fish is fusiform in adults, with median fins posteriorly positioned and pelvic fins in abdominal position. Skull bones are thick and squamation is heavy. The standard length of the largest specimen is 175 mm, that of the holotype is 140 mm, and that of the smallest is 78 mm.
Fossil Scleropages are known from the Maastrichtian of India, the Maastrichtian/Late Paleocene of Africa, the Paleocene of Europe, the Eocene of Sumatra, and the Oligocene of Australia. All of these earlier records are scales, otoliths and isolated fragments of bones. Therefore, this finding is the first skeletons of fossil Scleropages ever unearthed in the world with some specimens exceptionally well-preserved.
“This new fish resembles Scleropages in skull bones, caudal skeleton, the shape and position of fins, and reticulate scales. Therefore, it must belong to the genus”, said Dr. ZHANG Jiangyong of the IVPP.” (…) READ MORE
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