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1. chinaXiv:201708.00190 [pdf]

Small mammal taphonomy of three Miocene localities from Damiao, Nei Mongol, China

Leena SUKSELAINEN; Hannele PELTONEN; Anu KAAKINEN; ZHANG Zhao-Qun
分类: 地球科学 >> 地质学

Predation is the most common cause of death in small mammals. It also causes the greatest modification on their remains. Other postmortem processes, such as weathering, trampling, and transportation all modify bones and contribute to the forming assemblage. Here we examined three Miocene localities from Damiao, Nei Mongol, China with different fluvial subenvironments. The ages span from early Miocene to early late Miocene (ca 21–11.6 Ma). We describe the sedimentary context and taphonomic features of the small mammal assemblages, and identify the responsible agents for the fossil accumulations. Our study reveals predation as primary means of accumulation for all three localities. However, there is overprinting of other means of accumulation such as fluvial transportation and possibly signs of trampling at the two younger localities. Results indicate possibly different predators for all localities; owls for the oldest one, and diurnal birds of prey or mammalian agents for the younger two. We also show that systematic excavation for small mammals can be done, and in this way it may be possible to reduce some of the damage collecting always produces. 捕食是小哺乳动物死亡最常见的原因,也导致被捕食动物遗骸发生明显改变。动物死亡后的风化、踩踏、搬运等过程也会改变动物的骨骼并影响到化石组合的形成。本文研究了内蒙古大庙三个中新世化石地点,时代从早中新世到晚中新世早期(约21~11.6 ma)。通过分析各小哺乳动物化石组合的沉积背景以及埋藏学特征识别化石埋藏的主要成因。结果显示出捕食是三个地点小哺乳动物化石埋藏的基本成因,而在两个年轻的地点中也有流水搬运与可能的踩踏因素的叠加。三个地点可能存在不一样的捕食者:早中新世地点以猫头鹰捕食为主,中、晚中新世地点则以日间活动的鸟类或哺乳类为主要捕食者。研究还显示小哺乳动物的系统发掘是可行的,在一定程度上可以减少采样过程中产生的破坏。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:109, 下载量:49

2. chinaXiv:201708.00189 [pdf]

Elephas cf. E. planifrons (Elephantidae, Mammalia) from Upper Siwalik Subgroup of Samba district, Jammu and Kashmir, India

Som Nath KUNDAL ; Gyan BHADUR; Sandeep KUMAR
分类: 地球科学 >> 地质学

One specimen of Elephas cf. E. planifrons is reported and described here in the present paper. The specimen was recovered from the mudstone horizon underlying the volcanic ash bed exposed near the Nangal village, which is the extension of geochronological dated (2.48 Ma) volcanic ash beds exposed at Barakhetar in the Nagrota Formation of Upper Siwalik Subgroup of Samba district, Jammu and Kashmir, India. Based on the crown morphological parameters (plate numbers, molars length and width, crown length, width and height, enamel thickness, dentine thickness, length and width of plates, lamellar frequency, hypsodonty index and cement thickness), the specimen has been identified and is tentatively referred to Elephas cf. E. planifrons (LM3). The recovery of this specimen is of great significance as it extends its upper limit of range zone from 3.6–2.6 to 3.6–2.48 Ma. 报道和描述了一件平额象左侧M3化石。新材料产自Nangal村附近火山灰层之下的泥岩层,该火山灰是出露于查谟-克什米尔桑巴地区Barakhetar上西瓦立克亚群Nagrota组中年龄为2.48 Ma的火山灰层的延伸。根据齿板数,臼齿长和宽,齿冠长、宽和高,釉质和齿质厚度,齿板长和宽,齿脊频率,冠高指数以及白垩质厚度等齿冠形态参数,暂时将之归为Elephas cf. E. planifrons。新材料的发现将该种的分布上限从2.6 Ma提高到2.48 Ma

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:101, 下载量:60

3. chinaXiv:201708.00188 [pdf]

The morphology of Chiappeavis magnapremaxillo (Pengornithidae: Enantiornithes) and a comparison of aerodynamic function in Early Cretaceous avian tail fans

Jingmai K. O’CONNOR; ZHENG Xiao-Ting; HU Han; WANG Xiao-Li; ZHOU Zhong-He
分类: 地球科学 >> 地质学

We provide a complete description of the skeletal anatomy of the holotype of Chiappeavis magnapremaxillo, the first enantiornithine to preserve a rectricial fan, suggesting that possibly rectricial bulbs were present in basal members of this clade. Notably, Chiappeavis preserves a primitive palatal morphology in which the vomers reach the premaxillae similar to Archaeopteryx but unlike the condition in the Late Cretaceous enantiornithine Gobipteryx. If rectricial bulbs were present, pengornithid pygostyle morphology suggests they were minimally developed. We estimate the lift generated by the tail fan preserved in this specimen and compare it to the tail fans preserved in other Early Cretaceous birds. Aerodynamic models indicate the tail of Chiappeavis produced less lift than that of sympatric ornithuromorphs. This information provides a possible explanation for the absence of widespread aerodynamic tail morphologies in the Enantiornithes. 契氏鸟(Chiappeavis)是首次发现保存有扇状尾羽的反鸟类,显示出尾羽球茎这一结构在较原始的反鸟类中已经发育。详细描述了巨前颌契氏鸟(C. magnapremaxillo)正型标本的骨骼形态学特征。契氏鸟的腭区形态与始祖鸟(Archaeopteryx)相似,而区别于晚白垩世的反鸟类戈壁鸟(Gobipteryx)。即使具有尾羽球茎,鹏鸟类的尾综骨形态也表明该结构发育较差。估算了在契氏鸟中由扇状尾羽所产生的浮力,并与其他早白垩世鸟类进行对比。结果显示,契氏鸟的扇状尾羽所产生的空气浮力小于同时代生活的今鸟型类,这有可能解释了反鸟类中具有空气动力学功能的尾羽形态普遍缺乏的现象。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:86, 下载量:49

4. chinaXiv:201708.00187 [pdf]

Therocephalian (Therapsida) and chroniosuchian (Reptiliomorpha) from the Permo-Triassic transitional Guodikeng Formation of the Dalongkou Section, Jimsar, Xinjiang, China

LIU Jun; Fernando ABDALA
分类: 地球科学 >> 地质学

The Guodikeng Formation encompasses the terrestrial Permo-Triassic transition sequence in China. This formation crops out in the Dalongkou section, Jimsar, Xinjiang where remains of the dicynodonts Jimusaria and Lystrosaurus were found. We are describing here a therocephalian and a chroniosuchian from the Dalongkou section, which are the first records of these groups for the Guodikeng Formation. Diagnostic characters of the new therocephalian, Dalongkoua fuae gen. and sp. nov., include maxillary ventral margin strongly concave in lateral view; incisors spatulated and rounded; incisors and canines with faint serrations; coronoid process of the dentary with a marked external adductor fossa; triangular reflected lamina of the angular with two smooth concavities. Chroniosuchians are represented by several postcranial elements and the vertebral morphology is similar to Bystrowiana and Bystrowiella. These remains are interpreted as representing a Bystrowianidae indeterminate. The new findings increase the diversity of the Guodikeng Formation that is now represented by three or four dicynodonts, one therocephalian and one chroniosuchian. All these groups survived the massive P-T extinction but disappear from the fossil record in the Middle to Upper Triassic. 锅底坑组是重要的二叠—三叠系过渡序列,本组在新疆吉木萨尔大龙口出露广泛,产出吉木萨尔兽以及水龙兽两类二齿兽类。本文报道了在大龙口剖面首次发现的兽头类和迟滞鳄类,这也是此二类群在锅底坑组的首次报道。新发现的兽头类被命名为付氏大龙口兽(Dalongkoua fuae)。其鉴定特征包括上颌骨犬后齿齿槽外边缘向背向凹入;切齿有圆形和匙形;切齿和犬齿有微弱的锯齿;齿骨冠状突有显著的收肌窝;反折翼近三角形,有两个平滑的凹陷。锅底坑组目前有3~4属二齿兽类、1属兽头类和1属迟滞鳄类,这一发现增加了其多样性。这些类群都在二叠纪末的大灭绝中幸存下来,直到中晚三叠世才消失。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:67, 下载量:35

5. chinaXiv:201708.00186 [pdf]

First complete fossil Scleropages (Osteoglossomorpha)

ZHANG Jiang-Yong; Mark V H WILSON
分类: 地球科学 >> 地质学

A new species of osteoglossid fish, Scleropages sinensis sp. nov., is described from the Early Eocene Xiwanpu Formation in Hunan and the Yangxi Formation in Hubei, China. The new species was attributed to Scleropages, an extant genus of Osteoglossidae, because it very closely resembles the genus in skull bones, caudal skeleton, the shape and position of fins, and reticulate scales. The new fish is very similar to extant Scleropages except: the nasals do not appear to be ornamented; the sensory pore in the antorbital is large; the posterior infraorbitals are not quite covering the dorsal limb of the preopercle; the posteroventral angle of the preopercle is produced to point; the posteroventral margin of the opercle is concave and the ventral end of the bone is produced to a point; the pectoral fin is very long and extends well behind the beginning of the pelvic fin; the vertebral count is about 46?8; the parapophyses are shorter and the upper and lower caudal rays are nearly as long as the inner rays. The new fish is closer to its Asian neighbor, S. formosus, than to its southern relative, S. leichardti. Scleropages formosus inhabits natural lakes, swamps, flooded forests, and slowly moving, deep parts of rivers with overhanging vegetative cover. It is a carnivorous fish and its food consists mainly of insects, fishes, worms, small amphibians, small mammals, and even birds. S. sinensis may live in the same natural environment and have a similar diet except for the largest items. Sexual dimorphism may exist in S. sinensis. The presumed male has a slimmer and shallower body, a relatively larger head, and a deeper mouth cleft. The discovery of Scleropages sinensis sp. nov. dates the divergence of Scleropages and Osteoglossum to no later than the Early Eocene. 金龙鱼化石的鳞片和骨骼碎片在过去时有报道,但鉴定并非十分可靠,因为在骨舌鱼科鱼类中这些鳞片和骨骼十分相似。首次记述了保存完美的金龙鱼化石,标本产于湖南湘乡下湾铺组和湖北松滋洋溪组,确立为骨舌鱼科金龙鱼属一新种:中华金龙鱼Scleropages sinensis sp. nov.。新种与现生金龙鱼(Scleropages)在头部骨骼、尾骨骼、各鳍的形状和位置以及具有网状鳞片等方面极为相似,因而归入该属。然而,新种在以下特征上不同于金龙鱼的现生种:鼻骨无纹饰,鼻骨上的感觉管显露于沟内,感觉管联合不经过顶骨,翼耳骨侧向加厚,眶前骨上的感觉孔大,眼眶后的眶下骨不完全覆盖前鳃盖骨上支,其宽高比例为0.75而非现生种的1?.2, 前鳃盖骨后下角变尖,鳃盖骨后下缘凹形、下端变尖,匙骨背突长大,脊椎46?8, 椎体横突短小,胸鳍十分长大,上下两端的尾鳍条和内部鳍条等长。亚洲的现生种发现于各种河流和小溪中,比较喜欢水草茂盛的静水环境,一般游弋于表层水中,以鱼虾、昆虫等为食,新种中华金龙鱼也应该有相似的生长环境和食性。新种似具有性二形性,雄鱼体形略纤细,头部略大,口裂更深。中华金龙鱼化石的发现,说明金龙鱼属(Scleropages)和骨舌鱼属(Osteoglossum)在早始新世以前就已经分化,这对解释骨舌鱼类的跨洋分布具有十分重要的意义。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:92, 下载量:44

6. chinaXiv:201708.00185 [pdf]

Several rarely recorded rodents from the Neogene of China

QIU Zhu-Ding
分类: 地球科学 >> 地质学

Numerous assemblages of fossil small mammals have been recovered from the Neogene deposits in China over the last 30 years or so. Nevertheless, some taxa in these faunas are represented by only a small number of isolated teeth from very few localities, and these are often assigned as indeterminate genus or species. Four peculiar taxa of rodents, Sayimys sihongensis, Apeomys asiaticus, Neocometes sp. from the Early Miocene Xiacaowan Formation of Sihong, Jiangsu Province, and Yuneomys pusillus from the Late Miocene Shihuiba Formation of Lufeng, Yunnan Province, are described in detail. Comparison of these specimens with similar materials from Eurasia or North America makes distinction from the known species of related genera possible, and therefore two new species (S. sihongensis, A. asiaticus) are named for the Sihong specimens, although the material is rare. A new eomyid genus Yuneomys, previously published under the name Leptodontomys pusillus, is based on specimens from Lufeng. A. asiaticus and Neocometes sp. represent the first records of the genera Apeomys and Neocometes known from Asia and China, respectively. The occurrence of the Neogene rodents in eastern China improves our knowledge of the spatial distribution of these poorly recorded animals, and contributes to a better understanding of paleobiogeographic relationships in Eurasia. Co-occurrence of the new genus with the bunodont eomyids Plesieomys and Heteroeomys in the Lufeng Fauna seems to indicate a differentiation of eomyid taxa in northern and southern faunas of China, and may reflect ecological partitioning within southeastern Asia during the Miocene. 30多年来,中国新近纪堆积物中发现了大量的小哺乳动物化石,但一些种类的材料很少,而且仅在个别地点出现,在动物群中常以未定属、种记述。详细描述了4种罕见的啮齿动物,其中3种,泗洪豪鼠(Sayimys sihongensis)、亚洲别齿始鼠(Apeomys asiaticus)和新来鼠(未定种) (Neocometes sp.)发现于江苏泗洪早中新世下草湾组,一种,细小云南始鼠(Yuneomys pusillus)产自云南禄丰晚中新世石灰坝组。与欧亚或北美有关材料的比较研究表明,江苏泗洪标本无法归入相关属的任何已知种,因此被确定了两个新种(S. sihongensis和A. asiaticus); 禄丰原归入Leptodontomys pusillus的标本与该属的特征不符,被指定为新属Ynueomys。泗洪的A. asiaticus和Neocometes sp.分别代表该属在亚洲和中国的首次记录;它们与S. sihongensis在亚洲远东地区的出现,增加了我们对这些稀有动物地理分布和欧亚古生物地理关系的知识。禄丰的新属Yuneomys与共生的Plesieomys和Heteroeomys属同为丘齿型始鼠类,可能都属热带或亚热带森林型动物;在禄丰动物群中缺少脊齿型始鼠类,与华北动物群的组成不同,似乎表明华南和华北始鼠动物群在中新世期间已有明显的分异,进而支持这一时期亚洲出现了不同生态区系的设想。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:65, 下载量:31

7. chinaXiv:201708.00184 [pdf]

Review of historical and current research on the Late Cretaceous dinosaurs and dinosaur eggs from Laiyang, Shandong

ZHANG Jia-Liang; WANG Qiang; JIANG Shun-Xing; CHENG Xin; LI Ning; QIU Rui; ZHANG Xin-Jun; WANG Xiao-Lin
分类: 地球科学 >> 地质学

Here we briefly review the history of research on the Laiyang dinosaur and dinosaur egg faunas, summarize the contributions of C. C. Young and other elder paleontologists to the discoveries of the Late Cretaceous dinosaurs and dinosaur eggs from Laiyang, and introduce the new discoveries and the advances in the research on the Laiyang faunas. The new investigations in Laiyang from 2008 have found a series of valley developed in plain and more than ten new dinosaur or dinosaur egg fossil beds. In 2010, we began the massive excavations at two localities in Jingangkou and collected abundant dinosaurs and other vertebrate fossils, such as a new saurolophine, some theropod material and a new taxon of turtle egg. The bone beds in Locality 2 with the typical sedimentary and burial patterns of mudflow, and these fossil deposits are interpreted as having been carried and deposited by mudflow. The re-observation and the CT scanning data of the crest of Tsintaosaurus spinorhinus (IVPP V 725) show that the crest is fractured and solid. However, based on the re-observations of its cranial and postcranial specimens, we consider that Tsintaosaurus spinorhinus is a valid taxon of lambeosaurines, which have the hollow crest. Therefore, the crest of Tsintaosaurus might not belong to the skull of this individual, and the true form of the crest needs to be confirmed in the future work. We reassess the three species of Tanius, and obtain several results. 1) Tanius sinensis and Tanius chingkankouensis are the valid species of Tanius; 2) Tanius laiyangensis is invalid.; 3) the sacrum and ilium of Tanius chingkankouensis with typical hadrosaurid features should not be referred to Tanius. 简要回顾了莱阳恐龙和恐龙蛋化石群的研究历史和以杨钟健为代表的老一代地质古生物学者对莱阳恐龙和恐龙蛋研究和发现的杰出贡献,并介绍了莱阳恐龙和恐龙蛋的最新发现和若干研究进展。在近年来对莱阳周边地层进行的大规模考察中,发现了一系列发育在平原上的恐龙峡谷群;以及其中蕴含的十几个恐龙和恐龙蛋新地点和新层位。2010年开始,在对莱阳金岗口村附近的2个化石地点的发掘中,发现了以鸭嘴龙科为主的大量脊椎动物化石和蛋化石,包括一类新的栉龙亚科成员,一些大型兽脚类恐龙化石,以及一新的龟鳖类蛋化石等。2号地点化石富集层具有典型的泥石流沉积特征和骨骼埋藏特征。对棘鼻青岛龙的特殊头饰进行了CT扫描和三维重建,发现其头饰是实心结构,但其他骨骼特征证明棘鼻青岛龙属于具有头饰的赖氏龙亚科是确定无疑的,所以目前发现的头饰应不是其真实状态或根本不属于其头部骨骼。此外,对谭氏龙1属3种的重新观察研究得出以下结论:中国谭氏龙和金刚口谭氏龙应是有效属种,但部分骨骼还有疑问,还需要进一步研究,而莱阳谭氏龙为无效属种。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:54, 下载量:25

8. chinaXiv:201708.00183 [pdf]

New information on Dianmeisaurus gracilis Shang & Li, 2015

SHANG Qing-Hua; LI Chun; WU Xiao-Chun
分类: 地球科学 >> 地质学

Dianmeisaurus gracilis is restudied on the basis of a new specimen. It provides some new information, especially that on the skull roof, to the species. The most striking of those new characters include the snout (preorbital region) shorter than the orbit, the interorbital septum extremely narrow, the frontal with a sharp process at both ends, and the posterior margin of the skull roof deeply V-shaped. A phylogenetic analysis with new information confirms that Dianmeisaurus is the sister group of Diandongosaurus and that these two genera, together with those Chinese taxa (Majiashanosaurus, Dianopachysaurus, Keichousaurus, and Dawazisaurus), form a monophyletic clade which is more closely related to the Nothosauroidea than to a clade formed by the European pachypleurosaurs. 根据一件产自云南罗平中三叠世关岭组II段的新标本并结合产自相同地点和地层中的模式标本对纤细滇美龙(Dianmeisaurus gracilis Shang & Li, 2015)进行了详细研究。原模式标本暴露其腹面,而新标本暴露其背面,两者互相补充提供了更完整、精确的纤细滇美龙解剖学信息。新材料揭示该种具有非常短小的吻部,眶前区的长度不仅短于眶后区长度,甚至短于眼眶的长度;外鼻孔小且位置靠前,即鼻孔前区的长度短于鼻孔后缘与眼眶前缘之间的距离;由两额骨构成的眼眶间隔非常狭窄,宽度小于顶骨平台宽度的1/3;额骨前后两端均具渐尖的突起;顶骨后部不收缩,顶骨平台后缘呈深V型。补充了新信息和包含更多属种(如Dawazisaurus)后的系统发育学分析支持了之前滇美龙和滇东龙互为姊妹群的结论,同时它们和马家山龙、滇肿龙、贵州龙和大洼子龙一起构成了一个仅由中国的属种组成的单系类群。与欧洲肿肋龙类群(Dactylosaurus, Anarosaurus, Serpianosaurus和Neusticosaurus)相比,这一单系类群与幻龙类有更近的亲缘关系。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:13, 下载量:10

9. chinaXiv:201708.00182 [pdf]

New discoveries from the Sinokannemeyeria-Shansisuchus Assemblage Zone: 3. Archosauriformes from Linxian, Shanxi, China

LIU Jun; Corwin SULLIVAN
分类: 地球科学 >> 地质学

The tetrapod assemblage from the Middle Triassic upper part of the Ermaying Formation of northern China has been known for two decades as the Sinokannemeyeria-Shansisuchus Assemblage because of the characteristic presence of the dicynodont therapsid Sinokannemeyeria and the erythrosuchid archosauriform Shansisuchus. Recently a Sinokannemeyeria species has been described from Member I of the Tongchuan Formation, which overlies the Ermaying, near Baidaoyu, Linxian, Shanxi Province. Here we document archosauriform specimens from the Baidaoyu site, including a partial Shansisuchus skeleton and some additional bones from probable suchian archosaurs, which constitute the first archosauriform material known from Member I of the Tongchuan. The most intriguing archosauriform specimens are a large ilium probably attributable to an unusual poposauroid, and a small, strangely shaped element that appears to represent a highly autapomorphic suchian calcaneum. Given the presence of both Sinokannemeyeria and Shansisuchus at Baidaoyu, the stratigraphic range of the Sinokannemeyeria-Shansisuchus Assemblage can be considered to extend upward into the Tongchuan Formation, although with possible changes in faunal composition. The occurrence of a poposauroid ilium at the Baidaoyu locality adds to the evidence that poposauroids diversified extensively during the Middle Triassic. 近几十年,华北的二马营组上部地层以产出中国肯氏兽–山西鳄四足动物化石组合而闻名。最近在山西临县白道峪于上覆的铜川组一段发现了中国肯氏兽。本文描述了同一地点同一层位产出的主龙型类化石,包括一具山西鳄的部分骨架以及一些可以归入suchian的主龙类。它们是铜川组一段首次记述的主龙型类。最有鉴定特征的suchian材料包括一个大的髂骨以及一个小的、形状很奇特的、可能是跟骨的骨骼。髂骨可能可以归入一个奇异的波波龙类(poposauroid)。因为中国肯氏兽与山西鳄同时出现在白道峪,表明中国肯氏兽–山西鳄组合可以向上延伸到铜川组一段。髂骨与跟骨大小悬殊,可能代表两个从未在中国肯氏兽–山西鳄组合报道过的物种。白道峪发现了特化的波波龙类,支持了波波龙类在中三叠世大量分化的观点。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:21, 下载量:14

10. chinaXiv:201708.00181 [pdf]

A new tiny dromaeosaurid dinosaur from the Lower Cretaceous Jehol Group of western Liaoning and niche differentiation among the Jehol dromaeosaurids

XU Xing; QIN Zi-Chuan
分类: 地球科学 >> 地质学

The Early Cretaceous Jehol dromaeosaurids are taxonomically and morphologically diverse, and one of them, Microraptor zhaoianus, has been suggested to be among the smallest known non-avialan theropods. However, this idea is based on specimens of relatively early ontogenetic stages, and the lower limit of the mature body mass of Jehol dromaeosaurids thus remains unknown. Here we describe a new dromaeosaurid, Zhongjianosaurus yangi gen. et sp. nov., based on a specimen from the Lower Cretaceous Yixian Formation (the middle section of the Jehol Group) from Sihedang, Lingyuan County, Liaoning in Northeast China. While this new taxon is referable to the Microraptorinae, it differs from other microraptorine dromaeosaurids in numerous features, most notably the fusion of proportionally long uncinate processes to dorsal ribs, a humerus with a strongly medially offset proximal end and a large fenestra within the deltopectoral crest, an ulna slightly longer than the humerus, and an arctometatarsalian pes. Most significantly, the estimated 0.31 kg mass of the Z. yangi holotype of an adult individual confirms that some Jehol dromaeosaurids are among the smallest known non-avialan theropods. Our preliminary analysis demonstrates niche differentiation among the Jehol dromaeosaurids, a phenomenon rarely reported among Mesozoic dinosaurian faunas. 早白垩世热河生物群的驰龙类恐龙在分类和形态上多样化程度很高,其中的赵氏小盗龙曾被认为是已知体型最小的非鸟兽脚类恐龙之一。然而这个观点依据的标本都处于相对早期的生长发育阶段,因此热河生物群驰龙类恐龙的体型下限仍不明确。本文依据一件产自辽宁省凌源县四合当下白垩统义县组(热河群中部)的标本,描述驰龙类一新种,杨氏钟健龙。这一新种可归入小盗龙类,但它在很多特征上不同于其他小盗龙类,其中最明显的区别是其相对长的钩状突愈合于背肋上,肱骨具有强烈内倾的近端,肱骨三角嵴上有一窗孔,尺骨略长于肱骨,并具有窄跖型的足。最重要的是,已为成年个体的杨氏钟健龙正模估计体重约为0.31 kg, 这证实了热河生物群的一些驰龙类恐龙属于已知体型最小的非鸟恐龙。初步分析显示热河生物群驰龙类恐龙有生态位分化的情况,这一现象在中生代恐龙动物群中报道很少。

提交时间: 2017年08月10日 来自合作期刊:《古脊椎动物学报》 点击量:15, 下载量:11

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