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1.
An incomplete rostrum of a platypterygiine ichthyosaur (IGVR 94574) has recently been found near Tregnago (Verona, Italy), in the Lessini Mts. This is the first Cretaceous ichthyosaurian fossil found in Italy outside the northern Apennines, where fragmentary remains have been recovered since the 19th century.IGVR 94574 is a mid-distal rostral fragment infilled by a white, fine-grained limestone matrix. It consists of the premaxilla, nasal, vomer, dentary, and splenial, together with 20 teeth.Even if the exact horizon of provenance is unknown, analysis of the microfossil content of the matrix (planktonic foraminifera and calcareous nannofossils) allowed us to assign it to the lower part of the upper Albian. This is also the first Cretaceous ichthyosaur in Italy with a precise age: all previously reported fossils from the Apennines could not be dated due to the complete absence of microfossils in the surrounding matrix.We assign IGVR 94572 to Platypterygiinae; generic specification is not possible pending the taxonomic revision of the genus Platypterygius.Finally, the Tregnago rostrum is strikingly similar to the specimen IPUM 30139 from Gombola (Modena, Italy), stored in the collections of the Paleontological Museum of Modena and Reggio Emilia University and also attributable to a platypterygiine ichthyosaur. The comparison between these two fossils reveals the teeth are very similar both in shape and size.  相似文献   

2.
There are ten known Lower Cretaceous localities for skeletal remains of choristoderes in Siberia (Russia). Choristoderan remains at all these localities are represented by isolated bones, usually by isolated vertebrae of Choristodera indet. Three choristoderan taxa in two geological units were identified: the non-neochoristodere Khurendukhosaurus sp. (possibly closely related to the long-necked Sino-Japanese hyphalosaurids) from the Murtoi Formation, Transbaikalia; cf. Khurendukhosaurus sp. and the “Shestakovo choristodere” with possible neochoristoderan affinities from the Ilek Formation, Western Siberia. All these three choristoderan taxa had a microanatomical organization of vertebrae similar to that of in advanced large neochoristoderes (vertebral centra with tight spongiosa). The Siberian fossil record includes the westernmost (Shestakovo locality, Ilek Formation) and the northernmost (Teete locality, the Sangarian Group) occurrences of the Early Cretaceous choristoderes in Asia. Like in other regions of Asia, Siberian localities are characterized by the absence of neosuchian crocodyliforms.  相似文献   

3.
The Late Cretaceous (Santonian) continental vertebrate locality of Iharkút, western Hungary has provided numerous azhdarchid pterosaur remains including the recently described, Bakonydraco galaczi. Since the first report of these fossils, additional remains have been discovered that improve considerably our knowledge of some aspects of the anatomy of azhdarchid pterosaurs. New cranial material described here indicates an edentulous, non-crested premaxillary rostrum in Bakonydraco similar to that of Quetzalcoatlus and reveals that this rostrum was considerably thinner and more lightly built than the relatively massive, pointed mandibular symphysis. In addition, the contact surface of the upper and lower jaws of Bakonydraco at least in the symphyseal region was more similar to Tapejara wellnhoferi than to other azdarchids: the contact is irregular and the premaxilla does not fit closely the rostral part of the mandible. Among the postcranial material the atlas-axis complex possessing lateral pneumatic foramina is of great importance because it further supports the notion of interspecific variability of vertebral pneumaticity among pterosaurs.  相似文献   

4.
A new dinosaur sauropod from the Golmayo Formation (upper Hauterivian-lower Barremian) in Soria province (Spain) is described as Soriatitan golmayensis gen. et sp. nov. The new material consists of one tooth, three dorsal vertebrae with ribs, a partial sacrum, five caudal centra, two caudal vertebral spines, one chevron, a humerus, an ulna, a radius, two partial ilia, two ischia, a fragment of pubis, and a partial femur. Cladistic analysis identified the material as belonging to Brachiosaruidae within Titanosauriformes. Sauropod material from the Golmayo Formation shares a diagnostic feature with Abydosaurus, Cedarosaurus, Tastavinsaurus and Venenosaurus including anteriorly deflected anterior–middle caudal neural spines and with Cedarosaurus a proximodistally straight lateral margin between the proximal head and the shaft of the humerus. Eight characters are potential autapomorphies in the sauropod from Spain, including the presence of a large rectangular ventral ridge below the preacetabular process of the ilium, the same length of the pubic and ischiadic blades in the ischium, and two lateral ridges in the lateral area of the deltopectoral crest of the humerus. The presence of Early Cretaceous brachiosarids in both, North America and Europe, give support to the hypothesis of a connection between the tectonic plates of these continents at some point during the Early Cretaceous.  相似文献   

5.
A new polypore fungus beetle is described and illustrated, under the name of Thescelostrophus cretaceus gen. et sp. nov., representing the first documented occurrence of the tribe Eustrophini. The well-preserved specimen was collected from the Upper Cretaceous (Cenomanian, ca. 99 Ma) amber near the Hukawng Valley of northern Myanmar. This fossil species can be assigned to the extant subfamily Eustrophinae based on its elongate oval and strongly narrowed posteriorly body, simple and narrow tarsi, and somewhat clubbed antennomeres. The comparison among the extinct and extant eustrophines supports the previous hypothesis that antennal morphology of early eustrophines was very diverse. Additionally, an overall similarity between Thescelostrophus and extant eustrophines suggests a potential fungivory of this fossil species. Morphological characters preserved in the Burmese amber highlight the diversity of tetratomids during the Late Mesozoic and provide data for future phylogenetic studies of Tetratomidae.  相似文献   

6.
The upper Campanian-lower Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided a set of well-preserved partial skeletons in anatomical connection or with a low dispersion of their skeletal elements. One partial skeleton is herein described and a new titanosaurian sauropod is established, Lohuecotitan pandafilandi. This titanosaur is diagnosed by eight autapomorphic features: dorsally and ventrally widened or bifurcated posterior centrodiapophyseal lamina in anterior and middle dorsal vertebrae; short postspinal lamina with a transversely expanded distal end represented by smooth scars in the dorsal vertebrae; anteriormost caudals with the medial spinoprezygapophyseal and medial spinopostzygapophyseal laminae ventrally connected with the prespinal and postspinal laminae, respectively; anterior caudal neural spines with a dorsal projection of the prespinal and postspinal laminae; anterior caudal neural spines bears a “greek-cross”-like cross-section; middle caudal centra having two round and rough structures in the dorsal edge of the posterior articulation, which extends to the dorsal surface of the centrum; the articular ends of the rami of the haemal arches are divided in two articular surfaces; and tuberosity between the anterior and the lateral trochanter of the fibula. The herein performed phylogenetic analysis considered L. pandafilandi as a member of Lithostrotia more derived than Malawisaurus. The known palaeodiversity of the Late Cretaceous Ibero-Armorican titanosaurs is increasing, and further analyses focused on this group will be necessary to better understand the evolutionary history of European titanosaurs and to clarify their relationships within Titanosauria.  相似文献   

7.
Prejanopterus curvirostra, from the Early Cretaceous of La Rioja province, was the first pterosaur genus and species described from Spain. The material comprises disarticulated cranial and postcranial remains from several individuals. The fossil-bearing bed is assigned to the lacustrine Leza Formation (eastern Cameros Basin, NW margin of the Iberian Range). This unit is regarded as either Berriasian-Valanginian or Barremian-Aptian. Prejanopterus curvirostris (specific name emended) was originally diagnosed on the basis of several characters of which the most significant was a lateral curvature of the rostrum. Re-examination of the holotype (rostrum) and paratype (partial rostrum with teeth) indicates that there is no genuine sideways bend of the preserved premaxilla-maxilla segments, but a slight dorsal curvature. Prejanopterus is characterized by a unique combination of characters: an emended diagnosis is provided. In contrast with previous estimates, the wing span of Prejanopterus was probably not much (if ever) in excess of 2 m. A phylogenetic analysis suggests that Prejanopterus is a basal pterodactyloid positioned between Pterodactylus and Cycnorhamphus-Gallodactylus. Prejanopterus represents the first evidence of Pterodactylidae in the Early Cretaceous of the Iberian Peninsula.  相似文献   

8.
Among extant vertebrates, only birds have a respiratory system associated with pneumatic diverticula. However, several extinct clades also had pneumatic diverticula, including the sauropod dinosaurs. Among sauropods, Saltasaurini are characterized by extreme postcranial pneumaticity, which extends as far down the spinal column as the posterior caudal vertebrae. In this paper the pneumatic foramina in both the neural arches and the centra are described in detail, and the relative proportion of air spaces in the caudal vertebrae is established, revealing that the skeleton of Rocasaurus muniozi was more pneumatized than that of Neuquensaurus australis, with Saltasaurus loricatus intermediate. The level of pneumatization varies between the three saltasaurine taxa: in Neuquensaurus, only the neural arch is pneumatized, whereas in the other two saltasaurines both neural arches and centra are pneumatized. This allows us to hypothesize that the timing of pneumatization varied between the three species, with Rocasaurus muniozi pneumatized earliest in ontogeny. This ontogenetic pattern is correlated with evolutionary derivation: the most derived taxa show pneumatization in both the neural arch and the centrum.  相似文献   

9.
Tail anatomy of unenlagiid theropods remains poorly known. The most complete and informative taxon of this family is Buitreraptor gonzalezorum from the Upper Cretaceous of Rio Negro province, Argentina. The aim of the present contribution is to carry out an analysis of the tail anatomy of Buitreraptor based on its holotype and a newly collected specimen as well. Similarities shared by Buitreraptor, Rahonavis, Anchiornis and Archaeopteryx include: mid-caudal vertebrae with postzygapophyses longer than prezygapophyses, and mid-caudal centra with a system of lateral laminae and concavities. Preservation of paravian skeletons, as well as muscular reconstruction, indicate the presence of two different functional sections of the tail. This contribution sheds light on paravian tail evolution and provides new data on tail changes that occurred along the theropod line towards modern birds.  相似文献   

10.
11.
Two new species of Micropterigidae, Sabatinca cretacea sp. nov. and Sabatinca limula sp. nov. are described from the Upper Cretaceous Myanmar (Burmese) amber (99 Ma). Based on exquisitely preserved specimens with clear morphological characters and detailed structure of scales, the diagnosis of Sabatinca perveta is emended. Our new findings support that scales have developed various types and shapes by the Cretaceous. The extinct Sabatinca species represent a separate group that may be a transitional group from Australian lineage to extant Sabatinca.  相似文献   

12.
We describe a juvenile specimen of a titanosaurian sauropod dinosaur consisting of two dorsal and three caudal vertebral centra, an ilium fragment, and an ischium unearthed in 1991 from Site Km 153.5 at BR-050 highway in the Serra da Galga region, municipality of Uberaba, state of Minas Gerais, Brazil. The outcrop at the site is assigned to the Serra da Galga Member of the Marília Formation (Bauru Basin: Bauru Group; Upper Cretaceous: Maastrichtian). Although the material is very incomplete, features such as strongly procoelous caudal centra suggest an affinity with the titanosaurian clade Lithostrotia. The extensive vertebral pneumaticity with deep pleurocoels and well-developed camerae supports the hypothesis that, in titanosaurs, the air sac system was already present and fully developed even at early ontogenetic stages.  相似文献   

13.
本文描述了产自中国辽宁省北票市早白垩世义县组一新的伤齿龙类化石——柯氏辽宁猎龙(Liaoningvenator curriei gen. et sp. nov.)。它具有伤齿龙类以下特征: 数量众多且密集的上颌齿与下颌齿; 牙齿的齿冠与齿根之间显著收缩; 齿骨侧表面具有一沟, 营养孔位于该沟内; 远端尾椎背部的神经棘减弱为一个沟。它不同于其它伤齿龙类的特征主要为坐骨靴大, 侧面观近乎三角形, 坐骨闭孔突细长; 尾椎形态转变点位于第7尾椎。系统发育分析表明柯氏辽宁猎龙与短羽始中国羽龙(Eosinopteryx brevipenna)构成姊妹群, 位于同一分支内。它们具有如下共同特征: (1)上颌骨和下颌骨前面部分的牙齿前隆无锯齿; (2)颈肋较其相关节的椎体长; (3)肠骨前缘直。辽宁猎龙代表了辽西同等层位发现的第5个伤齿龙类。骨组织研究显示辽宁猎龙的骨骼已接近成熟, 死亡时至少4岁。它为该地区的基干伤齿龙类恐龙提供了新的解剖学信息, 并丰富了目前中国已知早白垩世伤齿龙类的多样性。  相似文献   

14.
Lirainosaurus astibiae was originally described by Sanz and collaborators in 1999 on the basis of a skull fragment, isolated teeth, several vertebrae (e.g. the holotypic anterior caudal vertebra) and appendicular bones from the Late Cretaceous of Laño (northern Spain). A review of all the vertebral remains, including new material (cervical, dorsal and caudal vertebrae, dorsal ribs, haemal arch), provides additional information about the axial skeleton of Lirainosaurus. A study of the laminae and fossae shows interesting variations in these structures in the axial series, especially concerning the prezygapophyses and diapophyses: e.g. the X-shaped morphology of the centroprezygapophyseal lamina only in the posterior dorsal vertebrae, and the division of the postzygodiapophyseal fossa into two fossae in the posterior dorsal vertebrae and the proximal caudal vertebrae. Two vertebral characters are here considered to be autapomorphic for L. astibiae: the presence of a lamina in the interzygapophyseal fossa in the most proximal caudal vertebrae (a postzygodiapophyseal lamina that separates the ventral postzygapophyseal centrodiapophyseal fossa and the dorsal postzygapophyseal spinodiapophyseal fossa), and the spinopostzygapophyseal structure not posteriorly projected in the posterior caudal vertebrae. The combination of characters present in the axial remains of Lirainosaurus astibiae supports the idea that it is a derived lithostrotian close to Saltasaurinae.  相似文献   

15.
A new genus and species of ripiphorid beetle is described based on a female specimen preserved in Upper Cretaceous (Cenomanian, ca. 99 Ma) amber from northern Myanmar, under the name of Spinotoma ruicheni gen. et sp. nov. It belongs to the extant Pelecotominae and represents the second documented occurrence of this subfamily in the Late Cretaceous. This new taxon is morphologically distinguishable in Pelecotominae by the combination of following characters: eyes oval, without incision; antennomeres V–X serrate, with XI fusiform; maxillary palpi unmodified; protarsi shorter than protibiae; tibiae sparsely provided with spines; tibial spurs formula 2-0-2. Together with other previously reported fossil ripiphorids, it highlights the species diversification of wedge-shaped beetles during their early evolution. On the other hand, a morphological similarity between Spinotoma and modern pelecotomines and the occurrence of xylophagous beetles in the Burmese amber suggest a similar host preference in wood-boring beetles for this species, shedding lights on an ancient host-parasitoid relationship in the late Mesozoic. This paper also provides a brief discussion on the taxonomy and evolution of Mesozoic wedge-shaped beetles. The wedged-shaped body form and fully-developed elytra in Recent Pelecotominae and Ptilophorinae are considered to be derived from their early ancestors rather than evolved with the onset of flowering plants during the Cretaceous as commonly thought.  相似文献   

16.
《China Geology》2018,1(1):28-35
An alvarezsaurid dinosaur skeleton was discovered from the Late Cretaceous Qiupa Formation of Luanchuan, Henan Province of central China. It represents a new alvarezsaurid dinosaur Qiupanykus zhangi gen. et sp. nov. A phylogenetic analysis recovers Qiupanykus nested within the unresolved clade, which includes Asian and north American taxa. The skeleton of the new specimen is preserved in association with eggshells. The eggshell morphologies show that these eggs belong to oviraptorid eggs, skeletal remains of which were discovered from the same area. The alvarezsaurid skeleton associated with eggshell fragments may indicate that these eggs were broken by the strong thumb-claws of the former and that alvarezsaurid dinosaurs may be egg-eaters.  相似文献   

17.
We report the first record of anilioids from southern South America, a region where they do not live today. The fossils come from the Allen Formation (Late Campanian–Early Maastrichtian) at Bajo Trapalcó and Bajo de Santa Rosa localities, Río Negro province, Argentina. The remains consist of several vertebrae, most of which belong to the mid–posterior precloacal region of the column. Comparisons to other extant and extinct anilioid taxa indicate that these remains represent a new taxon, Australophis anilioides gen. et sp. nov. Australophis is morphologically closer to Palaeocene Hoffstetterella from Brazil and extant South American Anilius than to any other snake. These taxa might be closely related, in which case they would represent a lineage distinct from that including Cylindrophis and uropeltids. The two lineages must have diverged by the Late Cretaceous.  相似文献   

18.
19.
Diagenesis of bone during fossilization is pervasive, however, the extent of this process varies with depositional environment. This study quantifies diagenesis of shark vertebral centra through analysis of a suite of physical and chemical characters including crystallinty index (CI), carbonate content, and elemental concentrations. Although shark skeletons are initially cartilaginous, the soft cartilage of the vertebral centra is replaced with carbonate hydroxyapatite during growth. Nine vertebral centra are analyzed from lamnoid (Lamnoidea) sharks ranging in age from the cretaceous to recent using Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma mass spectrometry (ICPMS). The variables CI, carbonate content, rare earth element (REE) concentrations, Ca/P, Ba/Ca, Sr/Ba, (La/Yb)N, (La/Y)N, (La/Yb)N vs. (La/Sm)N, La/Yb, and Ce anomalies elucidate the diagenetic and depositional environments of the seven fossil vertebral centra. The two extant centra demonstrate the initial, unaltered end-member conditions for these variables. Two fossil vertebral centra (Carcharodon megalodon and Isurus hastalis) demonstrate a strong terrestrial influence during diagenesis (distinctive flattening of shale-normalized REE patterns) that masked the seawater signal. Three centra (Carcharodon auriculatus, Carcharodon angustidens, and Creotxyrhina mantelli) have indications of some terrestrial influx evident by some flattening of the REE patterns relative to seawater. The terrestrial influence in these five shark centra (C. megalodon, I. hastalis, C. auriculatus, C. angustidens and C. mantelli) are interpreted to represent a primarily nearshore habitat for these species. In contrast, the two Otodus obliquus centra have REE patterns that represent the original seawater signal and have no indications of terrigenous input. These results indicate that fossil shark vertebral centra have the potential to understand diagenesis and reconstruct paleooceanographic environments.  相似文献   

20.
There are 24 known localities for skeletal remains of sauropod dinosaurs in the republics of Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan). Sauropod remains are very rare at all these localities and represented usually only by isolated teeth. Only narrow-crowned teeth are known from the Cretaceous of Central Asia. The oldest record of such teeth is from the Aptian Sultanbobo Formation of Uzbekistan. Exposures of the Turonian Bissekty Formation at the most productive vertebrate locality in the region, Dzharakuduk in Uzbekistan, has yielded many isolated teeth and a few skeletal remains that can be attributed to a non-lithostrotian titanosaur. Similar narrow-crowned, cylindrical teeth from Cenomanian-to Coniacian-age strata in the Kyzylkum Desert, Uzbekistan, may belong to a closely related taxon. Another taxon, with teeth that are pentagonal in cross-section, is known from the Santonian Yalovach and Bostobe formations of Tajikistan and western Kazakhstan, respectively. A femur reported from the Santonian Syuksyuk Formation of southern Kazakhstan possibly belongs to a lithostrotian titanosaur. The change in tooth structure at the Coniacian–Santonian boundary in the region possibly suggests replacement of non-lithostrotian titanosaurs by lithostrotians. The titanosaur from the Bissekty Formation is similar to Dongyangosaurus sinensis from the Cenomanian–Turonian of Zhejiang (China) in the extensive pneumatization of the neural arch on the anterior caudal vertebrae with several fossae. It also resembles Baotianmansaurus henanensis from the Cenomanian of Henan (China) in the possession of very short anterior caudal centra. These three taxa possibly represent an as yet formally unrecognized endemic clade of Asian non-lithostrotian titanosaurs.  相似文献   

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