云南昭通中新世末期鸟类动物群的组成及其时代意义北大核心CSCD

近年来,作者等人曾在云南昭通地区进行了多次野外大型化石发掘工作,在昭通组含褐煤的组合层中出土了大量的脊椎动物化石,其中以鸟类化石为最多,初步鉴定约860余件。经统计,这些鸟类分属于11目18科。此外,一同产出的还有鱼类、两栖类、爬行类,哺乳动物中的灵长类、长鼻类、奇蹄类、偶蹄类、食肉类、啮齿类、兔形类等化石,它们共同组成了一个新近纪早期(中新世末期)西南地区以鸟类为主的脊椎动物化石群。另外,从20世纪至今,在昭通组的时代界定上,长期以来观点尚不统一。文中根据新发现的动物群,特别是小哺乳动物的最新分析研究,结合古地磁测定结果,推测该动物群的年代应为中新世末期,较之以前的上新世—早更新世的时代结论大大提前。同时,昭通地区中新世鸟类动物群的发现,不仅填补了这一时期我国鸟类化石群的空白,而且对于新近纪鸟类演化的研究也具有重要意义。     

内蒙古哈拉津胡舒晚中新世动物群（英文）

过去40年,在内蒙古中部地区的陆相新近纪化石地点中应用了筛选技术,采集到大量标本,这些发现迅速填补着晚新生代动物群演替和生物年代学认识的空白。在把孤立的化石组合按时代先后进行排序和建立动物群序列框架中,小哺乳动物的发现和研究发挥了至关重要的作用。报道了另一个产自哈拉津胡舒地点的晚中新世动物群,这个动物群再次展示了蒙古高原上令人"叹为观止"的化石种类和丰度。新地点位于该地区的最北部,并为玄武岩所覆盖,产出的标本计有7000余件,代表大、小哺乳动物达63种。虽然这一动物群混杂了少量下部层位的属种,但它不失为内蒙古中部地区一个较为真实地反映晚中新世小哺乳动物组成和生态环境的动物群。初步分析表明,哈拉津胡舒动物群属中国陆生哺乳动物年代的晚中新世早期的灞河期,可能比阿木乌苏动物群稍晚,但比沙拉动物群略早。     

中国晚中新世陆相哺乳动物群序列:陕西蓝田的新证据(英文)

自 2 0世纪 60年代 ,陕西蓝田地区就以连续的晚新生代地层及丰富的哺乳动物化石而成为研究中国晚新生代哺乳动物与地层划分对比的经典地区之一。李传夔等 ( 1 984)根据灞河组发现的哺乳动物化石建立了灞河期 ,并与欧洲的Vallesian期对比。邱占祥等( 1 990 ,1 995)认为化石证据不充分 ,而将其与保德期合并。近年来 ,黄土高原三趾马红粘土大量的年代学资料表明 ,红粘土沉积最早可能开始于约 8Ma前。因此 ,狭义的保德期可能只代表了晚中新世晚期 ,晚中新世哺乳动物分期的再划分问题又重新被提出。自 1 997年以来 ,我们课题组在蓝田地区共发现 52个化石地点 ,其中的 2 6个含有哺乳动物化石 ,大哺乳动物化石标本共计 1 666件。经过详细野外地层测量 ,绘制了综合地层剖面 ,并将主要含哺乳动物化石的地点对比标定到综合地层剖面上。经过对各门类化石的初步研究 ,以及对已有化石材料的初步修订 ,到目前为止 ,陕西蓝田灞河组共计发现哺乳动物化石 45种 ,蓝田组 2 0种。新的化石证据表明 ,灞河组发现的哺乳动物化石组合完全不同于典型意义上的保德三趾马动物群。大哺乳动物化石以灞河三趾马与贾氏三趾马为代表 ,牛科化石组合在种级甚至属级上有明显的区别。大量的陕西转角羚羊 ,小型的Protoryx、Dorcadoryx以及Ga     

内蒙古中部敖尔班地区的岩石及生物地层(英文)

中国北方新近纪地层中,早中新世的哺乳动物化石地点比较稀少,化石面貌也不十分清楚。在内蒙古中部,尽管通古尔台地上有研究历史近百年的新近纪经典地点,但上世纪90年代发现的嘎顺音阿得格,依然是内蒙古目前惟一产出早中新世动物群的小盆地。同内蒙古诸多其他新近纪哺乳动物群一样,嘎顺音阿得格动物群与相邻动物群彼此缺乏时空上的联系,还不易建立可靠的层序关系。位于苏尼特左旗东南约60 km的敖尔班(曾用名"奥尔班",见Liddicoat et al.,2007),红色地层大面积出露,是2004年发现的一个新的哺乳动物化石地点。敖尔班剖面总厚50余米,大、小哺乳动物化石共生,岩性特征易识别,有利层位对比,是研究生物地层学的理想地点。自2004年以来,我们连续在敖尔班地区采集化石并进行地层工作,建立了一个较完整的哺乳动物序列,时代跨越早中新世晚期到晚中新世晚期。更加难得的是,敖尔班同一剖面上含有4个哺乳动物化石层位,其上下层序关系一目了然,在内蒙古新近纪地层中仅此一例。敖尔班哺乳动物序列的建立,无疑将对整个内蒙古中部新近纪,尤其是早中新世动物群面貌的了解具有促进作用。本文着重对敖尔班岩石地层进行描述,并结合我们4年来对脊椎动物化石的积累与认识,试图进一步完善内蒙古中部地区的生物地层层序,进而建立这一地区的年代地层框架。对化石的详细描述将适时发表。根据岩性及接触关系,敖尔班剖面可分为三大段:敖尔班组、巴伦哈拉根层及必鲁图层。敖尔班组(新建组)由一套红色和绿色的泥岩及粉砂岩组成,发育有成熟的古土壤层,厚约42 m,时代属于早中新世中晚期。敖尔班组的层型剖面建立在敖尔班露头出露最厚的中部,下部未见底,顶部与上覆巴伦哈拉根层呈假整合或不整合接触。该组目前已知分布仅局限于敖尔班露头。敖尔班组可进一步划分出三段:下红泥岩段、中绿泥岩段及上红泥岩段。三段呈连续沉积。敖尔班组与巴伦哈拉根层之间的假整合所代表的沉积间断延续了中中新世的大部分时段。巴伦哈拉根层为一套橘红色砂岩、粉砂岩及底砾岩,时代大致是最晚中中新世至最早晚中新世。不整合于巴伦哈拉根层之上是必鲁图层。两层之间似乎缺失了晚中新世的大部分堆积。必鲁图层的底砾岩是一种切割与充填构造,其中所含钙质结核及相当数量的化石都可能是巴伦哈拉根层原生堆积物再沉积的结果。必鲁图层的分布还需做更多工作,其时代可能是晚中新世晚期。主要依据小哺乳动物的组合,在敖尔班剖面中可建立4个动物群。最早为敖尔班组下红泥岩段产出的下敖尔班动物群。该动物群的特征是,小哺乳动物中在渐新世十分兴旺的一些科,如Ctenodactylidae,Tachyoryctoididae,Aplodontidae和Zapodidae还相当繁荣;中新世出现的属,如Mioechinus,Keramidomys,Heterosminthus和Democricetodon等占动物群总量的半数以上;大哺乳动物中残留有Palaeogale和裂爪兽。比下敖尔班动物群稍晚的是上敖尔班动物群,产出于敖尔班组的上红泥岩段。上敖尔班动物群的特征是,小哺乳动物在渐新世中占统治地位的一些科或完全绝迹,如Ctenodactylidae,或在种类和数量上明显减退,如Aplodontidae和Zapodidae;缺少在下敖尔班动物群中还相当常见的一些古老属,如Amphechinus,Tachyo- ryctoides和Sinolagomys等;出现了下敖尔班动物群中所没有的Megacricetodon,Cricetodon和Alloptox属;大哺乳动物中出现了长鼻类和柄杯鹿(Ligeromeryx/Lagomeryx)。经过相当长的一个沉积间断,敖尔班剖面的上部出现了巴伦哈拉根动物群。该动物群中渐新世常见的小哺乳动物科进一步衰落,同时出现了亚洲古北界晚中新世以后常见的跳鼠科(Dipodidae)和鼢鼠科(Siphneidae),具有明显的中中新世晚期或晚中新世早期生物组合的特点。最后是敖尔班剖面顶部必鲁图层中的必鲁图动物群。必鲁图动物群显然带有中中新世及晚中新世的混合特征,很可能是水流作用再沉积的结果。根据其中最进步分子的成分判断,估计必鲁图动物群的年代是晚中新世的晚期,其特征是,鼠科(Muridae)动物高度分化,而野兔科(Leporidae)尚未出现;含有晚中新世宝格达乌拉动物群或最晚中新世二登图动物群中大量出现的属种,如Lophocricetus grabaui,Paralactaga suni,Dipus fraudator和Hansdebruijnia pusilla等;但二登图动物群中很繁荣的一些属在必鲁图动物群中未被发现或者发现的个体数量很少,如Prospermophilus, Paralophicricetus和Microtodon等。     

晚中新世晚期土城子小哺乳动物组合及土城子动物群在内蒙古中部地区新近纪哺乳动物群序列中的位置（英文）

近百年来,在内蒙古中部地区发现了丰富的新近纪哺乳动物化石,命名和描述了10余个哺乳动物群,其时代跨越早中新世至早上新世。它们已经成为建立中国北方新近纪哺乳动物生物年代地层框架的重要依据。早在1959年中苏古生物联合考察过程中就已经发现土城子地区有丰富的哺乳动物化石,但这些化石以大–中型哺乳动物为主,缺乏小哺乳动物。土城子动物群的构成和其在中国北方新近纪哺乳动物年代地层框架中的位置长期以来不是特别明确。报道了在土城子新发现的6种小哺乳动物化石。根据Lophocricetus grabaui–Sinocricetus zdanskyi–Prosiphneus licenti–Hansdebruijnia pusilla–Moschus grandaevus的组合特点,认为土城子动物群的年代应该可以很好地约束在晚中新世(或者保德期)的晚期。土城子动物群明显比内蒙古的宝格达乌拉动物群要进步一些,与二登图动物群非常相似,时代上晚于前者,略早于后者。依据动物群整体面貌,推测在晚中新世晚期土城子地区存在森林和草原混合的环境。     

新疆准噶尔盆地北缘新近系顶山盐池组及相关地层问题

在新疆准噶尔盆地北缘乌伦古河流域建立了一个新近纪岩石地层单位:顶山盐池组。该组平行不整合于哈拉玛盖组之上,是一套以红色泥质粉砂岩为主体的细碎屑岩堆积,厚约50 m,含有上下两个化石带。上化石带时代为中新世晚期或上新世;下化石带为中中新世中晚期,与通古尔期默尔根小哺乳动物群大体相当。根据岩性和化石组合,推测顶山盐池组含有风成沉积物,或主要为风成堆积。其下部地层与流域中可可买登组为同期异相沉积。通过下伏的哈拉玛盖组,顶山盐池组可以和附近地区的铁尔斯哈巴合剖面衔接,构成乌伦古河流域一个从晚渐新世到中新世晚期或上新世大体连续的地层序列。这个序列有可能包含了塔本布鲁克期至保德期的沉积物和动物群。我们将这个序列与中国以及欧洲的相同时段生物年代序列进行了初步的对比,并讨论了有关的生物年代和年代地层问题。以哈拉玛盖动物群为代表的中中新世动物群的繁盛与它们的地理分布和中中新世全球气候最佳期的温暖气候可能相关。     

内蒙古中部中新世最晚期三趾马化石的新发现

<正>三趾马属(Hipparion)广泛分布于北美和旧大陆,它们在欧亚大陆的晚中新世和上新世期间特别繁盛,是地层对比和环境重建的重要生物标志。丰富的三趾马化石标本发现于中国许多的化石地点,主要产自红土堆积中。内蒙古中部的三趾马化石此前也发现于红土堆积,如化德县土城子和四子王旗乌兰花。这个地区的河湖相沉积中发现了大量小哺乳动物化石地点,但其中却很少有三趾马化石的报道,更缺乏详细的描述。     

临夏盆地的新生代地层及其哺乳动物化石证据

临夏盆地的新生代地层相当发育 ,保存了从渐新世至全新世的连续沉积序列。更为重要的是 ,这些沉积物中含有丰富的哺乳动物化石 ,为划分和对比临夏盆地的新生代地层提供了可靠的证据。然而 ,此前关于这个盆地地层层序和时代的认识有许多矛盾之处 ,地层命名繁复 ,化石证据混乱。近年来我们对临夏盆地的野外考察已理清了沉积序列 ,并在充分的哺乳动物化石证据的基础上重新厘定了各个岩石地层单位所对应的地质时代。临夏盆地的新生代哺乳动物化石以晚渐新世的巨犀动物群、中中新世的铲齿象动物群、晚中新世的三趾马动物群和早更新世的真马动物群最为丰富。     

横断山地区发现了丰富的哺乳类化石

<正> 中国科学院古脊椎动物与古人类研究所横断山野外队,82、83两年在横断山脉北、中、南段的藏东、川西、滇西十一个县内采集了比较丰富的哺乳动物化石,它们大都来自新发现的地点,代表了老第三纪的晚始新世和第四纪早、中、晚各个不同时期。从化石组成上看,它们包括了哺乳动物的啮齿类、兔形类、食肉类、蹄兔类、奇蹄类、偶蹄类、长鼻类以及灵长类。此外,还采集了许多鸟类肢骨和少量古人类材料和古文化遗物。     

甘肃临夏盆地首次发现乌米兽(牛科,偶蹄类)头骨化石（英文）

报道并描述了一件来自甘肃临夏盆地的中间乌米兽(Urmiatherium intermedium)头骨化石新材料,该材料产自柳树组上部,属于晚中新世晚期杨家山动物群。中间乌米兽是一种大型的晚中新世牛科动物,角心特化,短且呈薄板状,并且在基部相互靠近。在角心前后方的额骨和顶骨上,发育大片赘生骨疣,这些骨疣与角心一起,合称角器。20世纪初,步林报道了中国北方晚中新世地层中的大量中间乌米兽化石,包括产自山西保德和甘肃庆阳的20多件头骨以及很多破碎的齿列和骨骼。本文报道的乌米兽头骨化石是乌米兽在甘肃临夏盆地的首次发现,将其在中国北方的分布向西扩展到了青藏高原东北缘地带。乌米兽被普遍认为与近旋角羊(Plesiaddax)、和政羊(Hezhengia)和柴达木兽(Tsaidamotherium)等晚中新世"麝牛类"牛科动物具有较近的亲缘关系,但其系统发育地位仍存有争议。相比其他晚中新世"麝牛类"牛科动物,乌米兽的分布较广,从伊朗至中国北方都有分布,但它鲜与其他晚中新世"麝牛类"牛科动物伴生。在临夏盆地,与其伴生的牛科动物目前仅发现中华羚(Sinotragus)一种。     

Enigmatic didactyl tracks from the Jurassic of Iran

Didactyl tracks of theropod affinity are reported in this study based on a small sample of footprints in sandstones within the Middle Jurassic (Aalenian-Bajocian) Dansirit Formation in the Baladeh area, Alborz Mountains, Iran. These tracks superficially resemble footprints attributed to small deinonychosaurian dinosaurs known mainly from the Cretaceous of Asia. The relative length of the traces of digits III and IV is atypical for deinonychosaurids, especially dromaeosaurids, but could potentially be attributed to a troodontid-like trackmaker. The possibility of small Middle Jurassic deinonychosaurian trackmakers cannot be ruled out on the basis of the age of these traces. However, reports of pre-Cretaceous tracks of deinonychosaurian or deinoychosaur-like affinity remain rare and problematic. To date previous reports of pre-Cretaceous didactyl tracks pertain to a variable range of footprint morphologies, some of which predate known deinonychosaurian body fossil occurrences.     

Bird and Mammal Footprints From the Tertiary of Navarre (Western Pyrenees)

A rich variety of vertebrate footprints is known from a number of Upper Eocene to Lower Miocene localities of Navarre (western Pyrenees). The sediments were deposited in a wide range of depositional environments, from marginal marine to diversified terrestrial. Abundant bird tracks have been found in the coastal deposits of the Upper Eocene Liedena Sandstone of the Yesa and Itzagaondoa areas. Ciconiiformes-like (Leptoptilostipus pyrenaicus) and Charadriiformes-like (Charadriipeda ichnospp.) footprints have been recognized. Mammal ichnites have been discovered in the Oligocene and Lower Miocene deposits of Navarre. Equoid perissodactyl ichnites similar to those of Plagiolophustipus occur in the Oligocene fluviatile rocks of the Mués Sandstone of Olexoa and the Rocaforte Sandstone near Oibar and Sada. Trackways of entelodontids (Entelodontipus) are known in fluviatile-palustrine beds of the Oligocene Mués Sandstone of Olkotz. Additionally, bird (Charadriiformes-like) tracks are known in fluviatile-palustrine floodplain deposits of the Lower Miocene Ujué Formation of Los Arcos. In the same area, the Desoio and Los Arcos outcrops have also yielded perissodactyl trackways of possible Equoidea. Trackways of rhinocerotids (?) and artiodactyls (possibly Pecoripeda) are described from the Lower Miocene (Ramblian) palustrine limestones marginal to the Lerín Formation of Kaparroso and from alluvial fan deposits of the Uncastillo-Perdón Formation of Altzorritz, respectively.     

Crocodylian Tracks from Lower Oligocene Flysch deposits of the Barail Group,Manipur, India

A marine tidal delta siltstone from Gelmon locality in Northeast India preserved three crocodylian footprints and an elongate depression that appears to be a tail drag mark. Similar drag marks occur in nearby bedding surfaces. The discovery of crocodylian tracks from the basal part of Laisong Formation, Barail Group (Late Eocene–Early Oligocene age) of Manipur, India is noteworthy because of the age and the geographic location. Crocodylian tracks are rare in Cenozoic formations and they have not previously been reported from Asia. The footprints are herein named as a new ichnogenus and ichnospecies, Indosuchipes manipurensis.     

The Fossil Record of Vertebrate Tracks in Mexico

The fossil record of vertebrate tracks in Mexico is taxonomically rich and geographically diverse, and ranges in age from Middle Jurassic to Pleistocene and possibly Holocene. Middle Jurassic saurischian dinosaur tracks from Oaxaca represent the oldest record of vertebrate tracks in Mexico. Tracks attributed to Late Jurassic theropods and ornithopods are known from Michoacán. Theropod tracks of supposed Jurassic age are known from Durango. Lower Cretaceous Saurischian and ornithopod tracks are known from southern Puebla. Central Mexico has yielded Late Cretaceous hadrosaurid and sauropod tracks (Puebla), and tracks belonging to Theropoda and Ornithopoda (El Aguaje, Michoacan). In Coahuila several tracksites occur within the Cerro del Pueblo Formation and include tracks of mesoreptiles, pterosaurs, small to large theropods, bipedal and quadrupedal ornithopods, birds and possibly a mammal. A tracksite in the Olmos Formation includes tracks of turtles, crocodilians, medium-sized theropods, small ornithopods, and birds. Bird tracks of supposed Eocene age are known from Sinaloa. Two important Pleistocene ichnofaunas occur in the states of Puebla (Tepexi de Rodríguez) and Jalisco (San Juan de los Lagos), and include tracks of camelids, artiodactyls, small ungulates, elephants, large felids and birds. Pleistocene human tracks occur in Coahuila and Jalisco. Mexico's track record provides important insights into vertebrate diversity, paleoecology, and paleoenvironments. Given the rate of new discoveries since 1998, there is no doubt that new sites await to be found.     

The First Iguanodontid Dinosaur Tracks from the Swiss Alps (Schrattenkalk Formation,Aptian)

Until now dinosaur tracks from Switzerland were only known from Triassic and Late Jurassic strata. We report here for the first time the occurrence of ornithopod tracks from the Schrattenkalk Formation (Late Aptian) from the Swiss Central Alps. The locality is situated in an abandoned quarry on the shore of Lake Lucerne close to the village of Beckenried. The steeply inclined surface has more than 50 tracks (in three trackways) of ornithopod dinosaurs that are attributed to iguanodontids. Three trackways can be followed for distances of 25 to 35 m. The lengths the footprints (mean: 30 cm) point to animals ranging in size of from 4 to 6 m, with estimated hip heights between 1.8 and 2 m (hip height 6 FL) and 1.4 to 1.7 m (hip height 5 FL). One of the trackways shows two succesive manus impressions, indicating facultative quadrupedal gait. The track bearing layer consists of shallow water micrites with traces of emersion, and it is overlain by bioclastic grainstones. Previously the Upper Schrattenkalk Member in the Helvetic realm was thought to have formed on a large shelf far away from any continents. The present discovery will shed new light on the paleogeographic position of the Helvetic nappes.     

A diverse Upper Jurassic dinosaur ichnofauna from central‐west Portugal

Mateus, O. & Milàn, J. 2009: A diverse Upper Jurassic dinosaur ichnofauna from central‐west Portugal. Lethaia, Vol. 43, pp. 245–257. A newly discovered dinosaur track‐assemblage from the Upper Jurassic Lourinhã Formation (Lusitanian Basin, central‐west Portugal), comprises medium‐ to large‐sized sauropod tracks with well‐preserved impressions of soft tissue anatomy, stegosaur tracks and tracks from medium‐ to large‐sized theropods. The 400‐m‐thick Lourinhã Formation consists of mostly aluvial sediments, deposited during the early rifting of the Atlantic Ocean in the Kimmeridgian and Tithonian. The stratigraphic succession shows several shifts between flood‐plain mud and fluvial sands that favour preservation and fossilization of tracks. The studied track‐assemblage is found preserved as natural casts on the underside of a thin bivalve‐rich carbonate bed near the Tithonian–Kimmeridgian boundary. The diversity of the tracks from the new track assemblage is compared with similar faunas from the Upper Jurassic of Asturias, Spain and the Middle Jurassic Yorkshire Coast of England. The Portuguese record of Upper Jurassic dinosaur body fossils show close similarity to the track fauna from the Lourinhã Formation. □Dinosaur tracks, Lusitanian Basin, Portugal, skin impressions, Upper Jurassic.     

A theropod–sauropod track assemblage from the ?Middle–Upper Jurassic Shedian Formation at Shuangbai,Yunnan Province,China, reflecting different sizes of trackmakers: Review and new observations

A dinosaur tracksite at Hemenkou (Shuangbai County, Yunnan Province) in the ?Middle–Upper Jurassic Shedian Formation that consists mainly of gray-purple feldspathic quartz sandstones was previously reported incorrectly as being in the Lower Cretaceous Puchanghe Formation. The previous assignment is also inconsistent with two regional geological maps. Although mostly yielding poorly preserved tracks, the site nevertheless indicates a diversity of theropod and sauropod trackmakers partly consistent with the Late Jurassic body fossils from the region. Purported ornithopod are re-evaluated here as those of theropods. The theropod tracks and trackways show distinct similarities to those of the Grallator–Eubrontes plexus and can be subdivided into three morphotypes that may reflect different pes anatomy and/or substrate conditions. Two sizes of tracks (small, large) indicate the presence of different size classes or species in this area in the Late Jurassic. Similarly, the sauropod trackways document three differently sized trackmakers (small–medium–large) showing a typical wide-gauge (Brontopodus) pattern. The track record is the first evidence of theropods in the ?Middle–Late Jurassic of central Yunnan, whereas the sauropod tracks suggest a relation to the coeval basal eusauropods known from this region by skeletal remains.     

New localities of Late Eocene vertebrate footprints from the Tarom Mountains,Northwestern Iran

We document Late Eocene vertebrate footprints from the Tarom Mountains of Iran that represent a significant addition to the record of proboscidean and perissodactyl footprints. These footprints are from sandstones and tuffaceous sandstones of strata equivalent to the Kond Formation that overlie middle Eocene sedimentary rocks and are overlain by Oligocene volcanics. The footprints are preserved at 16 tracksites from 10 distinct stratigraphic levels. The mammal footprints include the oldest known proboscidean tracks, assigned to Proboscipeda enigmatica Panin & Avram and to cf. Proboscipeda isp. Evident perissodactyl tracks are common, tridactyl footprints with distinct digit shapes and proportions assigned to the new ichnogenus and ichnospecies Moropopus elongatus. Footprints of small, hopping, rodent-like mammals are identified as Musaltipes taromi new ichnospecies. Other mammal footprints from the Tarom tracksites are indeterminate, and bird footprints are assigned to Avipeda isp. The Tarom tracksites document the oldest record of proboscidean footprints, and this indicates that proboscideans had reached the northern shore of Tethys by Late Eocene time. The abundance and distinctiveness of the Tarom perissodactyl tracks mirrors the abundance and diversity of moropomorph perissodactyls during the Middle-Late Eocene. The Tarom tracksites are the most extensive record of Eocene vertebrate footprints known from Iran.

http://zoobank.org/urn:lsid:zoobank.org:pub:F430F9DB-728F-4162-9791-DC2A5CC5ED43     

Footprints of Giant Birds from the Upper Eocene of the Paris Basin: An Ichnological Enigma

In 1859 the French geologist Jules Desnoyers reported the discovery of vertebrate footprints in the Late Eocene gypsum of the Paris region. Although they attracted some attention at the time, those footprints were never illustrated or described in detail, and the present whereabouts of the specimens seem to be unknown. Several types of footprints were referable to animals known by skeletal elements from the gypsum, but some were not. Among the latter were tridactyl footprints of very large birds, which Desnoyers tentatively attributed to the giant ground bird Gastornis, which had been discovered in the Lower Eocene of the Paris region a few years earlier. Gastornithids are now known from the Paleocene to the Middle Eocene, but no skeletal remains of giant birds have yet been found in the Upper Eocene of Europe. The tracks of giant birds from the gypsum of the Paris region are thus an example of fossil footprints without known osteological counterparts, and the identity of the trackmakers remains an enigma.     

Dinoturbation in Upper Jurassic siliciclastic levels at Cabo Mondego (Lusitanian Basin,Portugal): evidences in a fluvial-dominated deltaic succession

At Cabo Mondego (western central Portugal), the Upper Jurassic marine to coastal succession contains several stratigraphic levels preserving dinosaur footprints on the surface bedding plane, as well as convolute bedding and soft sediment injection structures interpreted as dinoturbation structures. At least nineteen new three-dimensional structures observed in cross-sections are interpreted as produced by dinosaur trampling. The identification of three-dimensional structures of dinosaur footprints provides an important complement to the information obtained from footprints preserved on single bedding surfaces, such as the substrate consistency, potential trackmaker identification, and the possibility to enhance the distinction of sauropods and tridactyl dinosaurs, and paleoenvironmental interpretations. In the lower part of the Arenitos da Boa Viagem Formation, eight levels of probable lowermost Kimmeridgian age (ca. 157–156 Ma), displaying the above-mentioned deformational structures, were analyzed in detail. They support interpretations concerning the relationship between the footprints and the substrate consistency at the time of their formation. Three distinct cohesiveness patterns, defined by the penetration of the feet from the paleosurface, are the result of different degrees of substrate cohesiveness. Identifying the trackmakers of levels belonging to the middle Oxfordian–lower Kimmeridgian has important implications for Late Jurassic ecosystem reconstructions, as the footprints observed in Cabo Mondego indicate a change in the morphotypes throughout the Upper Jurassic succession.