Scientists from Nanjing Institute of Geology and Paleontology recently discovered a scorpion fossil on the seabed in the south of China. Fortunately, this dangerous creature-0/6 times longer than the existing average scorpion-lived at least 400 million years ago, not now!
This arachnid as big as a dog is called Xiushan Spider, which is a close relative of modern horseshoe crabs and whipping spiders. Its forelimbs have similar prickly attack forelimbs, belonging to the mixed pterodactyl-a group of broad-winged orders (sea scorpions)-and are also famous for their special arms, which are used to catch prey.
The author of the study explained: "Our understanding of mixed Spodoptera litura is limited to four species of two genera, which are based on some fossil specimens of Silurian Lourus 80 years ago." Well-preserved fossils provide new evidence for understanding the morphological diversity of mixed-winged insects.
This terrible beast is suspected to have lived in the Silurian period-about 443.8 million to 4.192 million years ago-where it was once a top underwater predator, feeding on fish and mollusks and having huge spiny arms called tentacles.
Earlier, studies showed that sea scorpions were top predators long before barracuda or sharks evolved. Based on the fossil specimens of Platycladus orientalis, the researchers concluded that sea scorpions use their tails (weapons made of serrated and prickly tips) to hunt prey.
However, Xiushan pterodactyl is the first reported hybrid pterodactyl in Gondwana supercontinent. Gondwana was formed when a large area of Pangu was divided into two, which shows that this group has the prejudice of insufficient collection.
The researchers said: "Future work, especially in Asia, may reveal that the distribution of mixed-winged insects and other wide-winged insects is more international."
This research will be published in the issue of 1 1 in Science Bulletin.
1 1 month, Dryopteris Xishan began to grow. Several precursor appendages were learned from the specimen, including buttock, single tentacle, reproductive gill cover and reproductive appendages. (S2d-i is online). Both hybrid pterodactyl and large pterodactyl have a very large and special second leg (III). The Hughmilleria appendages Ⅴ-Ⅴ and columnar cords observed in Spodoptera litura in Xiushan distinguish it from giant worms and support that it belongs to mixed type. The main difference between Taxus chinensis Xiushan and other mixed-wing purposes lies in the shape of appendages, including the way of rotation, the relative length of each football and the shape of the shaft. It is characterized in that two spines are left on the fourth football in Appendix III of the forebody; The longest spines (generally three) on each small pod (III-5 and III-6) are evenly arranged, with almost the same length, staggered with other spines with medium length; Appendix II, very short, with several pairs of thorns at the end; Appendices IV and V have slender spines at the end of each football, almost parallel to the direction in which the ends point.
Two larger specimens from the Grave Formation (almost contemporary with Xiushan Formation) include an appendage III, a carapace and part of the foreabdomen (Figure S2 a-c online). Let's call them Terropterus sp for the time being. Because their appendages III show the relative proportions of limb joints and basic spinal patterns similar to the corresponding appendages of Mangosteen Xiushan. However, the former is much larger in size, more sparse than Xiushan Mangosteen, and has a relatively longer spine. Without additional specimens, it is difficult to determine whether this arrangement reflects different species, or just because of individual development.
Based on the updated version of the matrix of Lamsdell et al., we put forward the phylogenetic analysis (documents S 1 and S2 online). [9] ; Dryopteris xiushanensis was added to the matrix to evaluate the phylogenetic position of this new taxa in platyptera A. We obtained the simplest tree, and analyzed that Dryopteris Xiushan is the sister group of Lanarkopterus dolichoschelus, so it is nested in Mixopteridae (Figure S3 is online). The topology recovered here is basically the same as that of Lamsdell et al. [9], and it is consistent with the morphology of the hybrid Chiroptera summarized above.
Mixed pteropods share the * * isomorphism of highly specialized spiny appendages, although there are significant differences among different genera. The morphological diversity of the mixed appendages of Xiushan pterodactyl is higher than previously thought. This is mainly reflected in the tattoo of foot strength and the relative length of each football with appendage III, the type of appendage II, the relative length of the distal thorn on each football with appendages IV and V, and Cox.
Up to now, the paleogeographic distribution of mixed pteropods (online in Figure S4) is very limited [5], [6], [7] and [8], and no examples of such animals have been found in Gondwana before. Our first Gondwana mixed pterodactyl —— together with other platyptera from China and some undescribed specimens —— indicates that this group is biased by insufficient collection [15]. Future work, especially in Asia, may reveal that the distribution of mixed-winged insects and other wide-winged insects is more international.
This work has won the strategic focus of the research and development plan of China Academy of Sciences (XDB26000000), the National Natural Science Foundation (4 1972006, 4 1688 103), the Key Frontier Scientific Research Plan of China Academy of Sciences (QYZDB-SSWDQC040) and the State Key Laboratory of Paleontology and Stratigraphy. This is the contribution of Edmund A. Jazbowski's Levelhelme Emergency Fellowship. Thanks to the field investigation and phylogenetic analysis provided by Sun Zhixin (NIGPAS), the reconstruction map provided by NIGPAS, the scanning electron microscope scanning provided by Wang Chunchao and Yan Fang, the sample photos provided by Zong Ruiwei (China Geo University, Wuhan) and the constructive suggestions made by anonymous recommenders.
Wang Bo designed this project. Hanwang, Wang Bo and Gai Zhikun wrote the manuscript. Jason Dunlop and Edmund A. Jarzembowski revised the draft and contributed to the analysis. Gai Zhikun, Wang Han and Lei Xiaojie participated in the field work and provided specimens. Wang Han made a phylogenetic analysis and prepared a chart. Lei Xiaojie participated in data collection and discussion.