A new Eocene catostomid (Teleostei: Cypriniformes) from northeastern China and early divergence of Catostomidae

Abstract

A new Eocene catostomid genus and species, †Plesiomyxocyprinus arratiae, is described from Huadian, Jilin Province, northeastern China. The materials include a nearly complete skeleton, dozens of pharyngeal bones with teeth, and a number of disarticulated bones. The new articulated specimen is large-sized and deep-bodied, with an estimated standard length of ca. 300 mm and body depth of 156 mm or about half of its standard length. The assignment of the fish to the Catostomidae is based on its falciform pharyngeal bone with one row of numerous (more than 50) compressed teeth, and the bone is much smaller than in cyprinids, especially given the size of the fish. The new fish distinguishes itself from all known catostomids (both extinct and extant) in its long anal fin with four unbranched and 17-18 branched rays, and its extremely short caudal peduncle that is only about one fourth of its depth. †Plesiomyxocyprinus arratiae resembles the Eocene-Oligocene transpacific-distributed †Amyzon in many general skeletal characters. However, it shows a few characters uniquely shared with the Recent catostomid Myxocyprinus asiaticus. Those include a very long dorsal fin with about 50 branched fin rays, the end of dorsal fin rays being close to the caudal fin base, and anal rays stretching posteriorly beyond the base of caudal fin. It is the first fossil catostomid that shows a close relationship to the endemic Myxocyprinus now living in the Yangtze River and Minjiang River, China. The discovery of †Plesiomyxocyprinus arratiae, along with two previously described possible catostomid genera †Jianghanichthys and †Vasnetzovia, may indicate that the divergence of the Catostomidae started much earlier, in the middle Eocene or earlier, on the western side of the Pacific than on its eastern side.a new catostomid genus, Eocene, northeastern China, early divergence

Mitogenomic perspectives on the origin of Tibetan loaches and their adaptation to high altitude

“…The following four fossil calibrations were incorporated in this study: 1) The minimum age of Catostomidae is 60 Ma based on a catostomid fossil from the Paleocene 61 . 2) The oldest fossil of Plesiomyxocyprinus arratiae similar to Myxocyprinus asiaticus was constrained to from the middle Eocene or earlier, approximately 38–40 Ma 62 . 3) The estimated divergence time between Cobitinae and Nemacheilinae is approximately 30 Ma 63 .…”

A Time-Calibrated Mitogenome Phylogeny of Catfish (Teleostei: Siluriformes)

“…tMRCA of Cobitoidei: The earliest cobitoid fossils from the family Catostomidae date back to the Early Paleocene (61.1–65.5 Ma) [62–64]. Lower age constraint of Cobitoidei = 61.1 Ma.…”

Molecular Phylogeny and Biogeography of Percocypris (Cyprinidae, Teleostei)

“…Ctenopharyngodon idella is the sister group of Mylopharyngodon piceusi [51], [52], and we assumed that the MRCA of Mylopharyngodon and its sister group was at least 12.5 Mya (log (mean)  =  “0.5” log (stdev)  =  “1.0” offset  = “12.5”). (4) The oldest fossil similar to Myxocyprinus asiaticus ( Plesiomyxocyprinus arratiae ) was recorded from the early to middle Eocene in China (37.2–40.4 Mya; [46], [53]). The split between Myxocyprinus and its sister group ( Carpiodes , Ictiobus , Cycleptus , Catostomus, Minytrema, Moxostoma and Hypenteliums ; e.g.…”