Chinese scholar Nature's latest cover article: "From fish to man" is the most critical leap in the history of vertebrate evolution

Recently, the team of academician Zhu Min of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences found the "Chongqing Special Buried Fossil Library" and "Guizhou Stone Fossil Library" in the strata of the early Silurian Period of about 440 million years ago in Chongqing, Guizhou and other places, adding another world-class special buried fossil library in China, filling the gap in the global early Silurian fossil record of jaws, and providing accurate evidence
for the rise of jaws and the earliest radiation differentiation for the first time 。 The team used new technologies and methods to conduct detailed research on these fish fossils, and made new progress in the exploration of important scientific issues such as the earliest differentiation of jaws, the evolution of vital organs and body configurations, and refreshed traditional cognition
.
On September 29, the British journal Nature published four academic papers by the team in the form of cover articles, focusing on the research
results on the origin and earliest evolution of jaws.

First, the research background

Including humans, 99.
8% of the extant vertebrates on Earth have jaws (maxilla and chin), collectively known as jawed vertebrates or jaws
.
The emergence and rise of jaws is one of the most critical leaps in the evolution of vertebrates "from fish to man", and many important organs and body configurations of human beings can be traced back to the beginning of the evolution of
jaws.
But when, where, and how did this jump occur? These questions require paleontological evidence to answer
.
However, there is a well-established fossil record of jaws that did not appear until the late Silurian period (425 million years ago), and the molecular clock inferred that the origin of jaws was no later than the late Ordovician 450 million years ago, so there was a huge gap
in the early evolution of jaws that lasted at least 30 million years and spanned the entire Silurian period 。 Alfred Romel, a giant of palevertebrate zoology, once called it "A persisting major gap in our paleontological record" (A.
S.
Romer, 1967, Science)

Because of this gap, although we know that jaws already existed in the Silurian period, we know nothing about what they looked like, how big they were, what niches they were in, how they evolved from each other, and even whether the sporadic spines and scales found in the Silurian strata belonged to jawed fish
.
The lack of fossil evidence has led to the origin and rise of jaws, one of the most critical jumps in the evolutionary history of vertebrates, which has been shrouded in a fog in the past, and jaws have been a "ghost branch" for the first 30 million years of their appearance
.

In the past ten years, Zhu Min's team has traveled to more than 200 places where the Silurian strata may contain fish in China, and finally found the "Chongqing Special Buried Fossil Library" and "Guizhou Stone Fossil Library" in the early Silurian strata of South China, found a large number of completely buried and preserved complete early Silurian fish fossils, and found the key
to solve the mystery of the initial rise of jaws and radiation differentiation 。 Using high-precision CT, trait big data analysis, fluid dynamics simulation and other new technologies and methods, the team showed the world for the first time the earliest jaw body structure and anatomical information such as the earliest jaw teeth, head, body and even fins, which were completely unknown in the past, providing conclusive evidence for answering a series of important scientific questions in the initial stage of "from fish to man" exploration, and rewriting all aspects of the
early evolution history of jaw vertebrates.

2.
Research findings and achievements

The "Guizhou Stone Fossil Library" is the latest period of the Elon period of Landoviris (early Silurian), about 439 million years ago, containing a large number of well-preserved jaw micro-body fossils
.
Among them, the tooth rotation of the Qianodus duplicis represents the oldest jaw-like tooth, pushing forward the earliest fossil evidence of the tooth by 14 million years
.
The discovery of the spines of the Fanjingshania renovata shows that as early as the early Silurian period, primitive cartilaginous fish had evolved a typical gage spiny morphology, while having the histological characteristics
of bony fish.
These developments also settled the dust on the long-standing debate over the taxonomy of Ordovician, Silurian fish scales and spiny fossils
.

The era of "Chongqing Special Buried Fossil Library" is the Landovi Lesterichi period, about 436 million years ago, which is the only special buried fossil library in the world that preserves complete jaw fossils from the early Silurian Period, which can be called "the dawn of fish"
.
This is another world-class special buried fossil library found in China after the Chengjiang biota and the Rehe biota, which provides a large number of key evidence for exploring important nodes in
the evolution of the tree of life, pushing forward the complete fossil record of jaws by 11 million years, and tracing the origin of several human body structures to fossil fish 436 million years ago.
The ancient fish fossils found in the Chongqing Special Buried Fossil Library are not only numerous and complete, but also very complete and exquisitely preserved, and we can get a glimpse of the vertebrates, especially jaws
, in the early Silurian period.

Among them, the jawless armored fish Tujiaaspis vividus provide key fossil evidence for the origin of vertebrate paired appendages; The jawed creepy Shenacanthus vermiformis is the earliest known well-preserved cartilaginous fish, confirming that sharks evolved from their "armored" ancestors
.
Another jawed fish, Xiushanosteus mirabilis, combines the characteristics of several shieldfish species, providing valuable information
for exploring the origin of the main taxa at the roots of the tree of jawed life and the evolution of vertebrate skulls.

Third, the significance

The discovery of the "Chongqing Specifically Buried Fossil Library" and the "Guizhou Stone Fossil Library" showed the face of the Silurian fish population, especially the jaws, on a large scale for the first time in the history of paleontology, revealing the process of the rise of the early jaws: at the latest, 440 million years ago, the major groups of jaws were already thriving in South China; by the late Silurian period, more diverse and larger jawed species appeared and began to spread around the world, opening the process of
fish landing and eventually evolving into humans.

The fossil research on the "Chongqing Special Buried Fossil Library" and the "Guizhou Stone Fossil Library" traces many anatomical structures related to humans to ancient fish 440 million years ago, filling the initial link missing in the evolutionary history of "from fish to man", updating the traditional understanding of the origin and rise of jaws, and further consolidating the evolutionary path
of "from fish to man".

Professor John Long, former president of the International Society of Vertebrate Paleontology and professor at Flinders University in Australia, learned about the team's work and wrote that "this is indeed an amazing, evolutionary fossil discovery that rewrites almost every aspect of the early evolutionary history of jaw vertebrates" (It's really an awesome, game changing-set of fossil discoveries.
It rewrites the almost everything we know about the early history of jawed animal evolution!）
。

It is foreseeable that the "Chongqing Special Buried Fossil Library" and the "Guizhou Stone Fossil Library" will continue to make continuous contributions
to solving the mysteries surrounding the origin of jaws in the future.

Academician Zhu Min's team includes researchers from Qujing Normal University and Chongqing Municipal Bureau of Planning and Natural Resources
.
This batch of research was supported
by the Strategic Pilot Project of the Chinese Academy of Sciences (Earth Big Data Science Project), Category B (Biological and Environmental Evolution Processes and Mechanisms in Key Geohistorical Periods), and the National Natural Science Foundation of China.

Nature magazine cover art