Apatosaurus knee joint disease
When researchers excavated the Apatosaurus femur specimen from the Morrison Formation in Wyoming (fossil number: UWGM 7213), they noticed that the lateral condyle and lateral epicondyle had inward erosion lesions. After preliminary determination, they believed that the lesion was the source of the disease. The inflammatory reaction caused by the erosion of soft tissues further stimulates the activity of osteoclasts and affects the bones. This knee joint pathology pattern is the first time it has been discovered in a sauropod dinosaur.
The researchers also found that the specimen’s lesions that affected mobility seemed to have recovered, because lesions that directly affect mobility in wild animals will make the individual’s chance of survival extremely low if not taken care of. , so this shows that Apatosaurus may have a group behavior of taking care of injured members.
This last paleopathological study helps improve our understanding of sauropod healing physiology.
The origin of the giant anaconda
The anaconda is one of the largest living snakes. However, humans know very little about the origins of giant snakes such as the anaconda. This is mainly because the fossils of these tropical snakes have not been studied enough.
The team of this study conducted field investigations in the Miocene strata of Venezuela and confirmed that the genus Anaconda belongs to Eunectes Fossil records, these fossil records were excavated in 13 different locations, with a total of 18 specimens, ranging in age from the middle Miocene 15 million years ago to the late Miocene 7 million years ago. The fossil record provides a complete history of body size changes in the genus Anaconda.
Preliminary analysis shows that as early as 15 million years ago, the genus Anaconda had a body size of about 5 meters long. This shows that the genus Anaconda already had larger bodies in the early evolutionary stages. body shape.
Although these fossil records are relatively large, they do not exceed the size of an anaconda. Compared with other super-giant species of reptiles born due to warm wetland climate during the same period, such as turtles, Prussian crocodiles, etc., the genus Anaconda is obviously not No similar situation has been shown, so the research team believes that this may be related to its life mode, such as prey size and quantity, growth rate, reproduction method, etc.
New method of fossil preservation
In paleontological research, fossils are one of the most important research samples. The preservation of fossils is a top priority. In particular, some fossils are very fragile. However, the selection of materials for preserving fossils needs to be carefully considered, especially with the recent importance of molecular paleontology. As the sensitivity gradually increases, materials that may chemically react with the fossil specimen itself must be removed.
A research team has tried to prepare fillers to fill the gaps between fossils to reduce the fragmentation of fossils due to collisions.
After several attempts, the research team successfully prepared a satisfactory formula. First, the game sand purchased from the hardware store was sieved through a 1.18mm filter and mixed evenly with sodium bentonite. The ratio of the two was 1 Ratio is 1, then add clean water, the ratio is about 3 parts sand and 7 parts water.
The filler made with this formula has almost no chemical activity and can be used on specimens with confidence. In addition, the ingredients of this filler are easy to obtain, cheap and can be reused. The team believes that it can be produced in large batches at one time and used at any time. , contributes to fossil protection at the excavation site.
Exploring the impact of forest composition on dinosaur fauna
In paleontological research, the composition of plants plays a very important role in understanding the environment and ecology at that time. In this study, the research team explored seven flora from northern Alberta, Canada, which are important for understanding the ecology and evolution of dinosaurs.
The first is the flora from about 190 million to 177 million years ago. Analysis of the stomach contents of Borealisaurus can clearly show that the main forest at that time was composed of conifers, seed ferns, horsetails and cycads. Judging from the bone fossils and trace fossils at that time, it can be clearly seen that the dominant position of large herbivores at that time was ankylosaurs.
Then came the period from 96 million years ago to 93 million years ago, when the local flora was dominated by diverse angiosperms and a small amount of metasequoia, and at that time it was still dominated by ankylosaurs. Forests in other formations at the same time also had similar combinations, and seed ferns no longer exist in the fossil records of these forests.
Finally, in the Late Cretaceous period from 76 to 74 million years ago, the forest crown was composed of coniferous plants such as metasequoia, while the middle and lower layers were mainly dominated by broad-leaved angiosperms and ginkgo. Animals at this time The group has also undergone tremendous changes, with the ankylosaurs almost disappearing and being replaced by hadrosaurs and, to a lesser extent, ceratopsians.
Although the reason why hadrosaurs replaced ankylosaurs should be caused by a combination of factors, the composition and diversity of forests as the main food source is likely to be one of the main factors, and the current research is It will help explain the relationship and degree of influence between flora and dinosaur evolution in the future.
Author: Bai Leng
References:
SVP 2023 PROGRAM GUIDE
83rd Annual Meeting
1. Acosta, M. R., Koenig, Elaude., Blomberg, O. H., Kufner, A. M., Haridy, Y., Lovelace, D. M. A UNIQUE PATHOLOGY IN AN APATOSAURINE (SAUROPODA, DIPLODOCIDAE) FEMUR FROM THE MORRISON FORMATION (UPPER JURASSIC) OF WYOMING, USA.
2. Alfonso Rojas, AF, Carrillo-Briceño, JD, Sánchez, R., Sanchez-Villagra, MR, Head, JJ AN EARLY ORIGIN OF GIGANTISM IN ANACONDAS (SERPENTES: EUNECTES) REVEALED BY THE FOSSIL RECORD.
3. Anné, J., Lund, E. K., Knowles, A., Herzog, L., Zanno, L. E. STABILIZING WITHOUT COMPROMISING: USING CASTING SAND TO STABILIZE FOSSIL BLOCKS.
4.Bamforth, E. EXPLORING THE ROLE OF EVOLVING FOREST COMPOSITION IN SHAPING DINOSAUR DIVERSITY PATTERNS IN THE CRETACEOUS OF NORTHERN ALBERTA, CANADA.
