IVPP scientists were conferred a second-class award of the 2013 State Natural Science Award (SNSA) in recognition of their achievements in the project “Studies on Origin and Early Evolution of Osteichthyes”. The award presentation ceremony was held today (January 10) in Beijing.
Osteichthyes, known as the bony vertebrates (bony fish and tetrapods), is the most diversified group of living vertebrates, including two major groups: Actinopterygii and Sarcopterygii. Following the cladistic classification, the Sarcopterygii includes not only lungfishes and coelacanths that still live in the water, but also tetrapods or land vertebrates including ourselves. Many human anatomical traits or body plan can be traced back to these fish-like remote ancestors, and therefore the origin and early evolution of osteichthyans definitely holds a critical position in the evolutionary history from fishes to human beings.
However, the fossil record of early osteichthyans had been poorly known till the end of last century, thus leaving major morphological gaps between actinopterygians and sarcopterygians, as well as some ‘missing links’ in the vertebrate family tree. Accordingly, the quest for the origin and early evolution of osteichthyans had been greatly hampered for a long time.
“We have found a huge amount of exceptionally preserved osteichthyan fossils”, said Prof. ZHU Min, the leading achiever of the project. He and his team members, Drs. ZHAO Wenjin, JIA Liantao, LU Jing and QIAO Tuo, have conducted a series of productive field investigations and excavations since 1996.
These fossils make a series of major breakthroughs about the origin and early evolution of osteichthyans. Psarolepis, with the unexpected character combination, provides important insight into the origin of osteichthyans. The oldest near-complete articulated Silurian osteichthyan, Guiyuoneiros, provides key data for a profound inquiry into the relationship among major groups of gnathostomes. The detailed study of Kenichthys disentangles the riddle on the origin of choana and the discovery of Sinostega pushes back the Asian tetrapod fossil record by some 100 million years, substantially extends the geographical range of tetrapods, and provides key data to quest the origin of tetrapods. The findings of Achoania, Meemannia and Styloichthys greatly increase the diversity of Siluro-Devonian osteichthyans, early sarcopterygians in particular, and corroborate the hypothesis of South China being the center of origin and early diversification of sarcopterygians.
The studies have provided crucial evidences for resolving several debated evolutionary problems, challenged entrenched ideas on these issues, and greatly advanced the research on the origin and early evolution of osteichthyans. Dr. Matt Friedman from University of Oxford, stated that in 2007: “over the past two decades, remarkable discoveries of early sarcopterygian remains in the Lower Devonian (Lochkovian) Xitun Formation of East Yunnan, China have greatly enriched our understanding of the diversity and interrelationships of the earliest osteichthyans.…… disrupting the taxonomic stability that prevailed for much of the latter half of the 20th century and challenging the status of previously inviolable groups.….., sparked a wave of systematic studies on early sarcopterygians that continues to this day”.