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Correlation of vertebrate assemblage of the Lower Lufeng Formation, Yunnan, China
... The Lufeng Fm. is 272 m thick, and composed of sediments of various grain sizes, mostly deep red and dark purple-red mudstones interbedded with thinly laminated siltstones (Zhang and Li, 1999;Fang et al., 2000). The deposition of the Lufeng Fm. is interpreted as the transition from a shallow lacustrine area to a plain with alluvial soils (Luo and Wu, 1995). These sediments have been dated as Early Jurassic (Luo and Wu, 1994), with further evidence supporting this dating provided by the Lufeng vertebrate assemblages, as well as those of its lateral equivalent, the Fengjiahe Fm. (Dong, 1992;Luo and Wu, 1994). ...
... The Lufeng Fm. has yielded amphibians, chelonians, crocodylomorphs, cynodonts, dinosaurs, lepidosaurs and mammals, among others (Young, 1951;Simmons, 1965;Luo and Wu, 1994). The dinosaur and mammal faunas from the Lufeng Fm. are considered equivalent to those of the upper Elliot Fm. in South Africa and the Trossingen Fm. in Germany (Luo and Wu, 1995;Reisz et al., 2013). A variety of invertebrate fossils have also been described from the Lufeng Fm. ...
An incomplete dinosaur skeleton, including a partial skull, recently discovered from the Lower Jurassic Lufeng Formation of Yunnan, China, is here described. Except for its small size, little anatomical evidence supports, a priori, the non‐adult status of this new sauropodomorph specimen. Thus, osteohistological analyses were conducted, which suggest that the new specimen is a fast‐growing juvenile. Despite the abundant early sauropodomorph fossils collected from the Lufeng Formation, it represents only the second occurrence of a juvenile non‐sauropodan sauropodomorph in the Lufeng Basin. The anatomy of the specimen does not match that of other Lower Jurassic immature specimens. Although cranial material is preserved, it does not display diagnostic characters of the early sauropodomorphs from the same horizon, namely Lufengosaurus, Yizhousaurus and Yunnanosaurus. Our phylogenetic analysis, which places the new specimen in a position relatively distant to other Chinese sauropodomorphs, corroborates the systematic hypothesis indicated by the anatomical evidence that it is not referable to a species already excavated in Yunnan. However, this result should be interpreted with caution considering that ontogeny affects phylogenetic reconstruction. A thorough comparison with adult forms, taking into account ontogeny‐related characters, suggests that this new juvenile specimen could represent an unknown species of early sauropodomorph.
... 1 地质概况 本文报道的化石材料产自云南省禄丰县的中南部。在该地的下、上禄丰组不仅发现了恐 龙和其它脊椎动物， 还发现无脊椎动物和植物化石 [3] 。 上、 下禄丰组广范地分布在禄丰县 (图 1) 。下禄丰组分为上下两层，下部为"Dull Purplish Bed"， 上部为"Dark Red Bed" [4] 。前 者主要为淡紫色的块状粉砂岩或砂岩，后者主要为棕褐色块状泥岩或粉砂岩或砂岩。根据底 层中所产脊椎动物群化石，估计其形成早侏罗世 [5] 。沉积特征显示为泛滥平原或湖成或流水 环境 [6] 。对方晓思等 [7] 提出的以沙湾段和张家坳段取代下禄丰组上下层之层名，目前尚存在 争论。 图 1 化石产地地里位置简图 ...
... This is based on the chemical composition of deposits (Tan 1997). Higher levels are interpreted as being deposited in piedmont plain, lake and fluvial environments, based on the vertebrate record (Luo and Wu 1995). ...
The new ichnospecies, Shenmuichnus wangi ichnosp. nov., is the first evidence for the presence of large ornithischians in the Early Jurassic of Yunnan Province, whereas the known skeletal record documents small species only. Until now Shenmuichnus was known from a single locality in Shaanxi Province by the ichnospecies Shenmuichnus youngteilhardorum. Compared with the latter, Shenmuichnus wangi is larger and shows a different trackway configuration, particularly in the relative position of manus and pes imprints. Palecologically, the occurrence of Shenmuichnus wangi in a red bed facies indicates the preference of distinctive environments of trackmakers of both ichnospecies, questioning former hypotheses of exclusivity of ornithischians in more humid climates. By abundance both skeletons and footprints of ornithischians suggest their role as a minor component in Early Jurassic saurischian dominated dinosaur faunas in this region.
The age of Yunnanosaurus youngi, a non-sauropod basal sauropodomorph, was reported as the Middle Jurassic. However, no basal sauropodomorphs have been reported worldwide in the Middle Jurassic previously, and only one clade of sauropodomorphs, Sauropoda, existed in the Middle Jurassic and became extinct by the end of the Cretaceous. Here, we further investigated the locality and its horizon of Yunnanosaurus youngi in Jiangyi, Yuanmou County, Yunnan Province, China. We found the species horizon is actually from the Lower Jurassic Fengjiahe Formation, and its age is probably Pliensbachian. Furthermore, the three known Yunnanosaurus-bearing horizons in Chuxiong, Yunnan can be correlated lithostratigraphically.
Abbreviations
FJHF: Fengjiahe Formation; LFF: Lufeng Formation; P: profile; TJB: Triassic-Jurassic boundary; YNOQ: quarry of Yunnanosaurus youngi; ZHF: Zhanghe Formation.
The cranial osteology of many prosauropod dinosaurs remains poorly described, hampering broader systematic studies of basal sauropodomorph interrelationships. Here, we present a detailed re-description of the skull of Lufengosaurus huenei Young. 1941a. from the Lower Lufeng Formation (Lower Jurassic) of China. Lufengosaurus can be diagnosed on the basis of four cranial autapomorphies (the presence of bony bosses on the ascending process of the maxilla, the jugal. and the rostrolateral wing of the parietal, and the presence of a ridge on the lateral surface of the maxilla) and distinguished from all other prosauropods by a unique combination of cranial character states. Previous suggestions that Lufengosaurus is congeneric with either Massospondylus or Yunnanosaurus are rejected on the basis of craniodental evidence. Comparison with published character codings for Lufengosaurus reveals numerous discrepancies that are demonstrated to affect the phylogenetic position of the genus and patterns of sauropodomorph interrelationships.
Yunnanosaurus youngi sp. nov. is erected based on the following characters: the distal ends of the sacral ribs expanded anteroposteriorly and dorsoventrally, forming into a sacrocostal yoke, which is contacting with the inner surface of ilium; the ischium is longer than the pubis. Yunnanosaurus youngi is about 13 meters long, which is longer than Yunnanosaurus huangi (7 meters long). The height exceeding the length for the centra of the posterior dorsal and anterior caudal vertebrae may be a synapopmorphy of Yunnanosauridae and Melanorosauridae. Yunnanosaurus youngi is stratigraphically younger than Y. huangi and it represents a derived form of yunnanosaurids.
The disappearance of nonavian dinosaurs is only a small part of a greater class of extinctions known as “mass extinctions.” Mass extinctions are global events characterized by unusually high rates of extinction. The five episodes of mass extinctions in Earth history are the Permo-Triassic extinction, the Late Ordovician extinction, the Late Devonian extinction, the Triassic-Jurassic extinction, and the Cretaceous-Tertiary (K/T) extinction. This chapter focuses on patterns of geologic and biotic changes that occurred during the Cretaceous-Tertiary (K/T) extinction. It also highlights the similarities and differences in interpretations of geologic and fossil records. It concludes with two scenarios explaining the differing views about dinosaur extinction.
Although the Crocodylomorpha spans a time period of over 200 million years, none of its notable morphological transitions appear to coincide with major geological boundaries. The Crocodylomorpha originated before the extinction event at the end of the Carnian Stage (Late Triassic), concomitant with a shift of locomotor pattern from bipedal erect posture to quadrupedal erect posture. With the successive divergence of the Sphenosuchia and Protosuchia the majority of features of the extant Crocodylia became established before the end of the Triassic. The Mesoeucrocodylia may have arisen in the early part of the Early Jurassic. The adoption of a more sprawling posture in the Longirostrine Taxa of the Mesoeucrocodylia was associated with a change of way of life from terrestrial to aquatic, probably immediately after the extinction event at the end of the Pliensbachian Stage (Jurassic). The Eusuchia arose in the Early Cretaceous, being characterized mainly by a complete bony secondary palate and the procoely of all vertebrae. The three extant clades most probably all arose before the Cretaceous-Tertiary boundary. Thus, the patterns of cladogenesis and diversification within the Crocodylomorpha indicate that, at least as currently understood, these taxa were prepared for the major environmental and biotic events that occurred during their history. Baden-Powell's motto of "be prepared" (Maynard 1946), taken from his own initials, appears to be an adequate descriptor of the history of the Crocodylomorpha.
Here we describe two instances of pathological vertebral fusion in two genera of sauropodomorph dinosaurs from the Early Jurassic Lufeng Formation in Yunnan, China. The first is a specimen, of Lufengosaurus huenei with two fused cervical vertebrae, and the other is a specimen of the Lufeng basal sauropod, with two fused caudal vertebrae. Both pathologies are consistent with spondyloarthropathy and represent the earliest known occurrence of that disease in dinosaurs. The two specimens affirm that early dinosaurs suffered from the same bone diseases as living vertebrates. Spondyloarthropathy in these dinosaurs may have been induced by long-term mechanical stress, such as weight bearing, and/or limited motion at the joint that would otherwise have inhibited such remodeling. In both cases, surface remodeling suggests that the animals survived well beyond the initiation of spondyloarthropathy.
Coelophysoid dinosaurs represent the earliest major radiation of neotheropods. These small-to-medium-sized agile bipeds lived throughout much of Pangaea during the Late Triassic-arly Jurassic. Previously reported coelophysoid material from Asia (excluding the Gondwanan territory of India) is limited to two specimens that comprise only limb fragments. This paper describes a new genus and species of coelophysoid, Panguraptor lufengensis, from the Lower Jurassic Lufeng Formation of Yunnan Province, China. The new taxon is represented by a well-preserved skeleton, including the skull and lower jaw, the presacral vertebral column and partial ribs, the right scapula, a partial forelimb, part of the pelvic girdle, and an almost complete hind limb. It is distinguished from other coelophysoid theropods by the unique combination of the following three character states: 1) diagonal (rostrodorsal-caudoventral) ridge on lateral surface of maxilla, within antorbital fossa, 2) elliptical, laterally facing fenestra caudodorsal to aforementioned diagonal ridge, and 3) hooked craniomedial corner of distal tarsal IV. Cladistic analysis recovers Panguraptor lufengensis deeply nested within Coelophysoidea as a member of Coelophysidae, and it is more closely related to Coelophysis than to "Syntarsus". Panguraptor represents the first well-preserved coelophysoid theropod dinosaur from Asia, and provides fresh evidence supporting the hypothesis that terrestrial tetrapods tended to be distributed pan-continentally during the Early Jurassic.
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