High-precision 3D printing technology is used in fossil fish research to study the fossils of fine shield fish.

The appearance of the jaw is one of the most important leaps in the evolution of vertebrates, the earliest jawed vertebrates are shield fish wearing large membrane bone pieces.
thought in the past that shield-skin fish were just a special sideline of jawed vertebrates and had been destroyed at the end of the 365 million-year-old mud basin.
but a series of recent studies have shown that all other jawed vertebrate groups evolved from an early branch of the shield fish.
therefore, the evolutionary relationship between the various branch groups of shield fish, and which physical characteristics of shield fish represent the original form of jaws, which are their own specialization, etc., are directly related to the origin of the body structure of modern jawed vertebrates, including humans, and thus get the attention of the academic community.
key to solving these problems is to maximize the "extracting" of anatomical information preserved in fossils.
the past detailed classical work on fossils of early fish such as real palm fin fish and Yang's fish, and has long provided important information for the study of vertebrate evolution.
however, unlike hard-bone fish, the endoskeletal system is composed mainly of cartilage, or is completely boneless, or only fragile and difficult to preserve the surrounding bone (osteo-bone osteoiesis).
Therefore, shield fish fossils often only preserve the membrane bone of the exoskeleton system, and its discovery is concentrated in the middle and late mud basin has been specialized genus species, early genus fossil discovery is less, the preservation status is not ideal.
A detailed study of a fine shield fish fossil from Australia's early mud basin 400 million years ago, using high-precision 3D printing technology in fossil fish research, by Lu Jing of the Institute of Paleovertebrates and Paleoanthusm of the Chinese Academy of Sciences, together with Gavin Young, Ph.D., ph.D., of the Australian National University, provides important new knowledge for the evolution of the original jaws.
paper was published in the August 10 issue of Scientific Reports.
specimens from this study, found in the 400 million-year-old early mud basin formation near The Australian capital, Canberra, are a nearly complete fossil preserved in calcium nods and the front half of the body, which has not been officially named.
This specimen is the size of a ping-pong ball, but it belongs to the Buchanosteidae, the ancestral type of dunk, a giant predator in the late mud basin that dominated the waters.
sharp toothbrusches in the body shape and jaw suggest that it should be a small predator that is active near the bottom of the water.
specimen was discovered as early as the late 1980s, but even after lengthy acid repairs, only a portion of the anatomical structure visible on the surface was revealed.
, acid-treated specimens become so fragile that detailed studies of them have been shelved for a long time.
recent years, new technologies such as microCT, computer reconstruction and high-precision 3D printing have made it possible to study this valuable and fragile specimen in detail.
In which high-precision 3D printing technology is the first time applied in the relevant research, it can be any size, any number, the computer reconstruction process virtual anatomy of the fine structure restored to a convenient repeated touch, manipulation, comparison of the entity, so that researchers can like the anatomy of modern biological specimens, the internal structure of extinct organisms for accurate flattening restoration and comparison research.
In early vertebrates, the structured complex skull consisted of several distinct cells, the top of which was covered with membrane skull skulls, the skulls made up of cartilage or bone cartilage, and the upper and lower jaws, arches, and caps, which were often hung loosely under the skull, so in most fossils, these units were either not preserved, dispersed, deformed, or significantly shifted.
But in this fossil, these units are not only well preserved, but, with the exception of a slight shift, basically maintain their position in life, allowing the researchers to restore the correspondence of fine joint surfaces, the range of activity of the upper and lower jaws, and the path of nerves and blood vessels in the jaws and cheeks. the
study also updated the understanding of many important structural features of this group, such as the hanging joint points of the upper jaw and the skull, the position of the upper and lower jaw joints, the hogeneous relationship between the cap cartilage attached to the skull and the tongue bow cartilage, etc., providing accurate information that has not been seen in other shield fish fossils.
article also attempts to compare the jaw structure of the genus with the corresponding structure of the hard-bone fish.
In recent years, a brand-new shield fish group, the full-jaw shield fish, has been discovered in the Zhilius system in Yunnan, China, which shows the jaw characteristics of the typical shield fish body and the typical hard bone fish, thus filling the morphological gap between the two groups to a large extent.
On the basis of these new knowledge, covering more subjects, further detailed comparative anatomy and systematic development analysis will undoubtedly continue to greatly promote the evolution of vertebrates jaws, and even the entire early evolution of vertebrates.
the study was funded by the National Natural Science Foundation of Australia and the Australian Research Council.
.