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1.
Seeds preserved in association with the holotype of Jeholornis prima provided the first direct evidence of granivory in any Mesozoic bird. Although this long boney-tailed bird also displays several morphological indicators correlated with herbivory such as reduced dentition and a deep mandible, Jeholornis has not been previously reported to possess a gastric mill. However, this feature is commonly linked to herbivory in theropod dinosaurs and present in at least one sympatric ornithuromorph and the basal pygostylian Sapeornis, which also preserve direct evidence of granivory. Here we describe gastrolith masses preserved in five specimens of Jeholornis. The cluster of gizzard stones is nearly identical in each specimen, consisting of a tightly associated mass of proportionately small stones. Three previously undescribed specimens preserving seeds are also identified. Unlike in Sapeornis and a previously described ornithuromorph, no specimen of Jeholornis preserves both seeds and gastroliths. This may be due to the fact that, unlike in other Early Cretaceous birds, the seeds preserved in specimens of Jeholornis are found in the abdomen, suggesting that Jeholornis may have resembled extant ratites in lacking an esophageal crop. Consistent differences in the preservation and morphology of the gastrolith mass between Jeholornis and other early birds hint at subtle variations in alimentary function among basal lineages. Differences in ingested seed morphology among taxa in turn suggest these functional variations may be at least partially related to differences in diet.  相似文献   

2.
In this note we report new avian remains from the Late Cretaceous Los Alamitos Formation (Campanian-Maastrichtian) at the Los Alamitos locality, Río Negro Province, Argentina. Isolated remains referable to indeterminate Aves, ?Patagopterygiformes, indeterminate Ornithurae, cf. Hesperornithes and cf. Neornithes are described and discussed. The new genus and species Alamitornis minutus is erected to include a minute-sized and gracile bird, probably related to the non-volant ratite-like bird Patagopteryx. If correctly identified, the record of Hesperornithes may be the first for this group in the Southern Hemisphere. The Los Alamitos paleoavifauna represents one of the most diverse fossil bird assemblage from the Mesozoic of Gondwana known to date.  相似文献   

3.
We describe a small ilium, with fibrous texture characteristic of juvenile bone, from the lower Cenomanian of central Utah, U.S.A. The ilium was recovered from the upper part of the Mussentuchit Member of the Cedar Mountain Formation. The ilium most closely resembles that of immature ceratopsid ilia referred to Agujaceratops mariscalensis from the Campanian Aguja Formation of southern Texas, U.S.A. Both have everted dorsal margins over the iliac body, subhorizontal postacetabular processes, and laterally compressed, anteroventrally curved preacetabular processes. If correctly identified, the small ilium from the Cedar Mountain Formation is the oldest ceratopsid or ceratopsoid known, and shows that the diversity of early ceratopsians was greater than previously realized.  相似文献   

4.
A well-preserved right humerus collected from the upper Austin Group at Ejido Piedritas in Coahuila, Mexico is referable to the carinate bird Ichthyornis. This occurrence extends the known distribution of Ichthyornis to the southwest, and is among a younger (Coniacian-Campanian) group of specimens, recovered generally to the south of older (Cenomanian-Turonian) Ichthyornis specimens. The southward shift in occurrence of Ichthyornis may accord with the withdrawal of subtropical marine biota from the Western Interior Seaway of North America during the Late Cretaceous.  相似文献   

5.
Four juvenile specimens referable to Pinacosaurus grangeri (Ankylosauria: Dinosauria) are described from the Campanian (Upper Cretaceous) locality Bayan Mandahu in northern Inner Mongolia Autonomous Region (People’s Republic of China). All the specimens preserve the skulls as well as, in some cases, mandibles, postcrania, and osteoderm. They are not taphonomically deformed by expanding matrix distortion, unlike many Gobi specimens, including the holotype of P. grangeri. Bayan Mandahu is also the type locality for Pinacosaurus mephistocephalus. The proximity in space and time of these two closely related species warrants a generic and specific revision for Pinacosaurus. The distinction of the two species is based on characters of the squamosal dermal elaborations, cranial roof posterior to the orbits, premaxillary notch, and distal margin of the ilium. Although a relatively well-represented ankylosaur taxon, the phylogenetic position of Pinacosaurus has not been unequivocally resolved. A new analysis recovers Pinacosaurus as the most basal member of the Ankylosaurinae.  相似文献   

6.
There are a growing number of Early Cretaceous avian tracks and trackways from around the world, with Asia (China and Korea) having the largest reported number and diversity of Mesozoic avian traces to date, and these new discoveries are increasing the Early Cretaceous avian ichnodivesrity of Laurasia. Here we report on a new Lower Cretaceous avian track locality in the Guanshan area, Yongjing County, Gansu Province, northwest China, and on a novel ichnospecies of Koreanaornis, Koreanaornis lii ichnosp. nov. Koreananornis lii is distinct from other Koreanaornipodidae in that it possesses a consistently wider digit divarication than previously described tridactyl tracks, and possess a short, small, posteromedially oriented hallux that displays a different orientation than that seen in Koreanaornis hamanensis. The lack of linear and angular data reported for digit I traces of many avian ichnotaxa has the potential to give misleading results in multivariate statistical analyses. Also, the wide divarication of Koreanaornis lii causes the ichnotaxon to not group with other Koreanornipodidae in multivariate analyses, but with Ignotornidae. Despite the results of the analyses, K. lii is morphologically distinct from these ichnotaxa. The results demonstrate that relying solely on multivariate statistical analyses without careful examination of footprint morphology will result in erroneous ichnospecies groupings. While new vertebrate ichnotaxa discoveries from Asia may support the hypotheses of the presence of a unique and endemic Asian vertebrate ichnofauna during the Cretaceous, the recent discovery of skeletal remains interpreted to be of a volant wading bird from the Early Cretaceous, and recent reports of tracks from volant avians, could suggest that flighted avians of the shore- and wading bird ecotypes could have had a Laurasian-wide distribution during the Early Cretaceous. However, strong convergence in foot morphology of shore- and wading birds suggests that avian ichnotaxa found in both present-day Asia and North America may have been made by birds endemic to eastern and western Laurasia during the Early Cretaceous.  相似文献   

7.
《Comptes Rendus Geoscience》2018,350(6):310-318
The sabkha of Gueran in the Southwest Moroccan Sahara has yielded a rich and diverse fauna of late middle Eocene vertebrates that include the world's richest Bartonian age archaeocete assemblage. Archeocete remains were described previously and here we report on the rest of the vertebrate fauna. The Gueran fauna includes abundant chondrichthyan species belonging to Lamniformes, Carcharhiniformes and Rhinopristiformes, and actinopterygian assemblage consisting of Cylindracanthus, of a siluriform, and of Perciformes. Turtles are represented by at least two marine taxa referred to as Cheloniidae and Dermochelyidae. Crocodylian remains belong to at least two longirostrine species, including gavialoid remains. Snakes are represented by Pterosphenus cf. schweinfurthi (Palaeophiidae). Seabirds are represented by a pseudo-toothed bird (Pelagornithidae). The avian fossil belonged to a gigantic soaring bird and constitutes the earliest occurrence of the genus Pelagornis. The presence of proboscideans is attested by dental fragments. This fossil assemblage from Gueran shows affinities with those of the Eocene beds of Egypt and Libya. The numerous shared taxa support a close biogeographical connection between faunas from southeastern and southwestern coasts of the Mediterranean Sea.  相似文献   

8.
A large theropod ilium was recently collected from the Upper Cretaceous Honglishan Formation in the Sangequan area of the northern Junggar Basin, Xinjiang, China, which represents the first officially reported dinosaur fossil from this formation. Several morphological features, including robust supracetabular ridge, reduced supracetabular crest, concave anterior margin of the pubic peduncle, ventral flange on the pubic peduncle, converging dorsal surface of the iliac blades, laterally visible cuppedicus shelf, and ventral flange on the posterior surface of pubic peduncle, suggest that this specimen can be referred to Tyrannosaurinae, and furthermore, a few differences between this specimen and other tyrannosaurines in particular the contemporary Asian tyrannosaurine Tarbosaurus suggest that IVPP V22757 may represent a new tyrannosaurine species. However, in the absence of extensive data that would make it possible to properly evaluate these differences, we refrain from naming a new taxon based on this specimen. Some insect borings are also identified in this specimen, and are referable to the ichnogenus Cubiculum, which is interpreted as the insect pupichnia. This new fossil documents the presence of a gigantic theropod in the Upper Cretaceous of Junggar Basin, adding new information on its poorly studied ecosystems.  相似文献   

9.
Ornithuromorph birds (the clade which includes modern avian radiation) first appeared in the Early Cretaceous in Asia and achieved a great diversity during the latest ages of the Late Cretaceous (Campanian and Maastrichtian). The evolutionary history of orithuromorphs during the first 17 MYAs of the Late Cretaceous (Cenomanian to Santonian ages) remains very poorly known, as the fossil record for this time interval is largely restricted to several isolated finds of the classic avian genus Ichthyornis in North America. Here we describe an isolated distal tibiotarsus of an evolutionary advanced bird, morphologically similar to Ichthyornis, from the middle Cenomanian of Saratov Province, European Russia. This is the first documentation of an Ichthyornis-like bird in the Old World. The find further constitutes only the second pre-Campanian record of the Late Cretaceous Ornithuromorpha in Eurasia, the second record of Cenomanian birds in Russia. This discovery shows that Ichthyornis-like birds enjoyed a wide geographical distribution as early as the beginning of the Late Cretaceous. Given that the earliest and the most primitive ornithuromorph birds are known from Asia, the new find supports a Eurasian origin for Ichthyornithidae.  相似文献   

10.
Although body fossils of shorebirds and shorebird-like species are extremely rare from the Cretaceous, rapid increase in the discovery of bird footprint sites provides valuable alternate evidence to help fill gaps in the story of the early evolution of shorebird-like species. Newly discovered bird tracks from the Albian-Cenomanian Dakota Formation in northeastern Utah represent the first report of the ichnogenus Koreanaornis from North America and only the second report of bird tracks from this formation. These tracks are not attributable to Aquatilavipes as previously claimed. Three well-preserved trackways are described and provisionally referred to Koreanaornis cf. hamanensis (Kim). However, a review of the ichnotaxonomy of shorebird ichnites reveals that this ichnotaxon also closely resembles the Miocene ichnospecies Avipeda sirin (Vyalov). This latter comparison points to the need for a thorough evaluation of the similarity between Mesozoic and Cenozoic avian ichnotaxa, which may be over-split in some cases and under-differentiated in others.The new material helps distinguish ichnogenus Koreanaornis from the larger bird track Aquatilavipes, which is more abundant and widespread in North America. In some cases Aquatilavipes has been incorrectly used as a catch-all ichnogenus both in North America and Asia. The Dakota Formation stratigraphy at the tracksite indicates that the track makers lived in a marginal marine paleoenvironment. However, despite the widespread distribution of such facies, often replete with dinosaur tracks, the bird track record of the Dakota Formation, and the Cretaceous of the western USA remains relatively sparse in comparison with other areas such as east Asia.  相似文献   

11.
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   

12.
A partial, associated skeleton with feather impressions of a bird from early Cretaceous (Neocomian) deposits in Mongolia constitutes a new family and order (Ambiortidae, Ambiortiformes). The specimen presents a mosaic of archaic and specialised characters within the Class Aves and shows that advanced carinate birds existed some 10 to 12 million years after Archaeopteryx, lending tentative support to the idea that Archaeopteryx may not be representative of the state of avian evolution in the late Jurassic. The new specimen and numerous feather impressions from other early Cretaceous localities in Mongolia and the Soviet Union, indicate that birds were probably common in early Cretaceous biotas.  相似文献   

13.
The spatial scale of habitat selection has become a prominent concept in ecology, but has received less attention in coastal ecology. In coastal marshes, broad-scale marsh types are defined by vegetation composition over thousands of hectares, water-level management is applied over hundreds of hectares, and fine-scale habitat is depicted by tens of meters. Individually, these scales are known to affect wetland fauna, but studies have not examined all three spatial scales simultaneously. We investigated wetland bird habitat selection at the three scales and compared single- and multiscale models. From 2009 to 2011, we surveyed marsh birds (i.e., Rallidae, bitterns, grebes), shorebirds, and wading birds in fresh and intermediate (oligohaline) coastal marsh in Louisiana and Texas, USA. Within each year, six repeated surveys of wintering, resident, and migratory breeding birds were conducted at >100 points (n?=?304). The results revealed fine-scale factors, primarily water depth, were consistently better predictors than marsh type or management. However, 10 of 11 species had improved models with the three scales combined. Birds with a linear association with water depth were, correspondingly, most abundant with deeper fresh marsh and permanently impounded water. Conversely, intermediate marsh had a greater abundance of shallow water species, such as king rail Rallus elegans, least bittern Ixobrychus exilis, and sora Porzana carolina. These birds had quadratic relationships with water depth or no relationship. Overall, coastal birds were influenced by multiple scales corresponding with hydrological characteristics. The effects suggest the timing of drawdowns and interannual variability in spring water levels can greatly affect wetland bird abundance.  相似文献   

14.
We report on a new enantiornithine bird, Dunhuangia cuii, gen. et sp. nov., from the Lower Cretaceous Xiagou Formation of the Changma Basin, northwestern China. Although the material is incomplete, Dunhuangia cuii preserves unique coracoidal and sternal morphologies that distinguish it from other known enantiornithines; this specimen represents only the second enantiornithine reported from the Changma Basin that is diagnostic at the species level. This study enriches our understanding of the enantiornithine component of this ornithuromorph-dominated, Early Cretaceous avifauna.  相似文献   

15.
A new bird ichnotaxon found in Cenicero (La Rioja, Ebro Basin, Spain) is described here. The footprints are preserved in sandstone beds in a central-distal alluvial fringe with a mud-dominated floodplain, located in the transition unit between the Nájera and Haro formations. This level is positioned between the Y and Z local Agenian biozones (lower Miocene). The footprints were preliminarily studied in another work and considered as an indeterminate ichnotaxon. Uvaichnites riojana ichnogen. nov. and ichnosp. nov. is a tridactyl footprint characterized by a prominent central pad, very large to enormous sized, with unjointed toes at the proximal end. These features differ from Aquatilavipes, Aviadactyla, Avipeda, Ludicharadripodiscus, Fuscinapeda, and Ornithotarnocia of the Avipedidae morphofamily. U. riojana is considered to be similar to common crane (Grus grus) footprints in the Gruidae family. There are a few references about this family in the Iberian Peninsula and Balearic Islands and this find could confirm the presence of Gruidae since at least the lower Miocene.  相似文献   

16.
Dongyangopelta yangyanensis gen. et sp. nov. from the Chaochuan Formation (Albian-Cenomanian) of Dongyang, Zhejiang Province, China is characterized: the convex anterior surface of the first presacral rod centrum strongly inflates laterally and slightly curves posteriorly; the fused pelvic shield composes of larger pebble-shaped bosses, defined by smaller tubercles or flat stretches of bone; most osteoderms are heavily roughened with notches and grooves for dermal attachment along the edge; domed triradiate osteoderm is present; sigmoid curvature of the dorsal surface of the ilium is present; the preacetabular process curves lateroventrally at the anterior end and has a shallow groove in the edge of the lateral and anterior ends and strong lateromedial expansion of the distal femur. The femoral head is well separated from the greater trochanter, indicating that Dongyangopelta is a nodosaurid ankylosaur, the second from southeast China. Phylogenetic analysis also positions this taxon in the Nodosauridae clade. Dongyangopelta differs from Zhejiangosaurus in the characters of presacral rod, ilium, and femur. Dongyangopelta represents the first ankylosaur outside North America and Europe that definitively possesses a pelvic shield with fused armor.  相似文献   

17.
Although hardly applied to human palaeoecology, bird fossils offer a unique opportunity for quantitative studies of the hominin habitat. Here we reconstruct the Homo habitat niche across a large area of the Palaearctic, based on a database of avian fauna for Pleistocene sites. Our results reveal a striking association between Homo and habitat mosaics. A mix of open savannah-type woodland, wetlands and rocky habitats emerges as the predominant combination occupied by Homo across a wide geographical area, from the earliest populations of the Lower Palaeolithic to the latest hunter-gatherer communities of the Upper Palaeolithic. This observation is in keeping with the view that such landscapes have had long standing selective value for hominins.  相似文献   

18.
Fossil bird material is exceptionally rare in the Mesozoic of western Asia. With the notable exception of the Upper Cretaceous foot-propelled diving bird Asiahesperornis bazhanovi from northern Kazakhstan, the only bird fossils described from this region have been bone fragments from the Upper Cretaceous of Uzbekistan. In this paper, all material referred to date to the hesperornithiform Asiahesperornis is reviewed and re-described. New postcranial elements of this taxon from the holotype Kushmurun locality (Maastrichtian Zhuravlovskaya Svita) are presented, and the taxonomic history and likely affinities of this ocean-going bird are discussed.  相似文献   

19.
We evaluated the distribution of waterfowl in relation to a seagrass (Ruppia maritima) patch, to infauna, and on its relationship with substrate characteristics. An experiment performed in the Mar Chiquita coastal lagoon (37°46′S, 57°27′W; Argentina) was used to evaluate the effect of herbivory on widgeon grass,R. maritima. Control plots of equal size, located between bird exclosures, were exposed to herbivory. The experiment ran for 31 d, starting on December 1, 1994. Censuses showed that black-necked swan ( $\bar x = 50$ birds ha?1, SD = 37, n = 10) and coots ( $\bar x = 42$ birds ha?1, SD = 28, n = 10) were the most important (always present) of the waterfowl seen feeding onR. maritima. The results of the experiment showed greater leaf lengths, lower belowground (rhizomes and roots) biomass, greater aboveground (leaves and shoots) biomass, and greater abundance of the polychaeteHeteromastus similis in exclosure plots. There were no exclosure effects on total biomass (belowground plus aboveground), reproductive parts (fruits and pre- and postpollination flowers), or abundance of most benthic infauna. Topographic surveys showed that sediment surface was higher within theR. maritima patches, but there were no significant differences in granulometric composition. Surveys also showed that bird distribution was strongly associated with the presence ofR. maritima.  相似文献   

20.
本文描述了产于中国辽宁凌源早白垩世九佛堂组地层的一件鸟类化石标本。该标本中等大小,具有许多原始今鸟型鸟类的共同衍征;同时该标本也具有一个区别与其他已知原始今鸟型鸟类的长吻:吻长超过整个头骨长的70%;前颌骨前端尖而下钩,向前超出下颌前端,下颌齿骨前端直,仅上颌骨和齿骨上具有牙齿,代表了原始今鸟型鸟类一个新的属种和一个新的生态类型,因此建立了一个今鸟型鸟类新属种——张氏觉华鸟(Juehuaornis zhangi gen.et sp.nov)。  相似文献   

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