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1.
记述发现于辽宁省朝阳县原家洼村中生代地层中的反鸟类一新科:真翼鸟科(Alethoalaornithidae fam.nov.)。由于该科鸟类具有肩胛骨直,第1、2指仍有爪,腓骨和胫跗骨不愈合,趾骨不太钩曲等特征,将真翼鸟科归入华夏鸟目(Cathayornithiformes)。真翼鸟科的特有特征包括:吻尖,齿少,牙齿退化的趋势明显,腕掌骨基本形成,乌喙骨远端宽,肱骨近端具明显的气窝,尾综骨长,跗蹠骨末端三趾骨等长且滑车末端基本处于同一水平面,趾骨爪长,不甚钩曲等。通过对新材料和其它早期鸟类的对比认为,反鸟类的灭绝不仅有自身构造的原因,还有它们所生活的生态环境多变的原因。  相似文献   

2.
中国广西晚白垩世一新的巨龙类恐龙   总被引:2,自引:0,他引:2  
记述了采自广西南宁市郊晚白垩世地层中一巨龙类恐龙新属种:右江清秀龙(Qingxiu- saurus youjiangensis gen.et sp.nov.)。新属种正型标本包括以下不关联的头后骨骼:一段较完整的前部尾椎神经棘、左右胸骨板、左右肱骨。它以以下独特特征组合区别于其他巨龙类:前部尾椎神经棘板状结构不发育、相对较高并呈桨状;胸骨与肱骨最大长之比值较低(约0.65)。广西发现的新属种以及近年来报道的巨龙类恐龙材料表明,亚洲巨龙类恐龙的头后骨骼形态变异度高,白垩纪时期这类恐龙曾在亚洲广为分布。  相似文献   

3.
Since Mivart (1865), Cacajao, Chiropotes, and Pithecia have been grouped into a single taxon, which he called the subfamily Pitheciinae but which I, following Rosenberger (this issue), refer to as the living members of the tribe Pitheciini. While few today doubt the association of these three living genera, not all would place them together with Aotus and Callicebus in the subfamily Pitheciinae. This is an attempt to sort out the behavioral and morphological features of feeding and dental morphology in these taxa. Extant members of the tribe Pitheciini are adapted for sclerocarpic foraging, morphological evidence for which is found in the fossils of Soriacebus and Cebupithecia. Sclerocarpic foraging in living pitheciins is a two-stage process of seed predation involving 1) specialized features of the anterior dentition that allow removal of a hard pericarp that protects a seed or seeds, followed by 2) mastication by the posterior dentition having low cusp relief to triturate nutritious seeds of a relatively soft and uniformly pliable consistency. The dentitions of fossil pitheciins, Soriacebus and Cebupithecia, demonstrate that the hypertrophy of lower incisors plus the robustness and flaring of the canine precede development of low cusp relief on molars and premolars in the evolution of morphological features associated with sclerocarpic foraging. Features of sclerocarpic foraging are found less uniformly in the other two pitheciines, Callicebus and Aotus.  相似文献   

4.
Embryonic remains within a small (4.75 by 2.23 cm) egg from the Late Cretaceous, Mongolia are here re-described. High-resolution X-ray computed tomography (HRCT) was used to digitally prepare and describe the enclosed embryonic bones. The egg, IGM (Mongolian Institute for Geology, Ulaanbaatar) 100/2010, with a three-part shell microstructure, was originally assigned to Neoceratopsia implying extensive homoplasy among eggshell characters across Dinosauria. Re-examination finds the forelimb significantly longer than the hindlimbs, proportions suggesting an avian identification. Additional, postcranial apomorphies (strut-like coracoid, cranially located humeral condyles, olecranon fossa, slender radius relative to the ulna, trochanteric crest on the femur, and ulna longer than the humerus) identify the embryo as avian. Presence of a dorsal coracoid fossa and a craniocaudally compressed distal humerus with a strongly angled distal margin support a diagnosis of IGM 100/2010 as an enantiornithine. Re-identification eliminates the implied homoplasy of this tri-laminate eggshell structure, and instead associates enantiornithine birds with eggshell microstructure composed of a mammillary, squamatic, and external zones. Posture of the embryo follows that of other theropods with fore- and hindlimbs folded parallel to the vertebral column and the elbow pointing caudally just dorsal to the knees. The size of the egg and embryo of IGM 100/2010 is similar to the two other Mongolian enantiornithine eggs. Well-ossified skeletons, as in this specimen, characterize all known enantiornithine embryos suggesting precocial hatchlings, comparing closely to late stage embryos of modern precocial birds that are both flight- and run-capable upon hatching. Extensive ossification in enantiornithine embryos may contribute to their relatively abundant representation in the fossil record. Neoceratopsian eggs remain unrecognized in the fossil record.  相似文献   

5.
A new psittaciform bird from the Lower Eocene (Ypresian) London Clay of England is described. This taxon, Pulchrapollia gracilis gen. et sp. nov., is assigned to the order Psittaciformes (parrots) on the basis of several distinctive structures of the tarsometatarsus, namely the trochlea for metatarsal III (trochlea metatarsi III) bearing a tubercle on its lateral side and the trochlea for metatarsal IV (trochlea metatarsi IV) completely retroverted (fully zygodactyl foot). Comparisons with other fossil and Recent taxa further support this conclusion. Cladistic analysis shows that Pulchrapollia is the sister-taxon of the single extant family within Psittaciformes, the Psittacidae. Palaeopsittacus georgei, a taxon previously described from the London Clay, is most likely based on some unassociated material and is regarded here as incertae sedis.  相似文献   

6.
We describe a new stem group representative of Pici (woodpeckers, honeyguides, barbets, and allies) from the early Oligocene (Rupelian) of the Czech Republic. The holotype of Picavus litencicensis, gen. et sp. nov. is a postcranial skeleton with well-preserved feather remains. The new species is distinguished from crown group Pici in several plesiomorphic features and is assigned to the new taxon Picavidae, fam. nov. The absence of an elongated accessory trochlea for the reversed fourth toe shows P. litencicensis to be the most basal representative of Pici, and concerning the morphology of the distal tarsometatarsus the species represents a morphological link between Pici and their sister taxon, the Galbulae. Like all other early Oligocene piciform birds, P. litencicensis is a tiny bird, the size of the smallest extant Pici. Because all Palaeogene Pici were found in Europe and some of these are outside the crown group, an Old World origin of Pici is likely. With definitive crown group representatives of Pici being unknown before the late Oligocene/early Miocene, the fossil record does not support earlier molecular calibrations, which resulted in a late Cretaceous divergence of crown group Pici.  相似文献   

7.
A new genus and species of platyrrhine primate, Nuciruptor rubricae, are added to the increasingly diverse primate fauna from the middle Miocene of La Venta, Colombia. This species displays a number of dental and gnathic features indicating that it is related to living and extinct Pitheciinae (extant Callicebus, Pithecia, Chiropotes, Cacajao, and the Colombian middle Miocene Cebupithecia sarmientoi). Nuciruptor is markedly more derived than Callicebus but possesses a less derived mandibular form and incisor-canine complex than extant and extinct pitheciins (Cebupithecia, Pithecia, Chiropotes, and Cacajao), suggesting that it is a primitive member of the tribe Pitheciini within the larger monophyletic Pitheciinae. Nuciruptor has procumbent and moderately elongate lower incisors and low-crowned molars, suggesting that it was a seed predator, as are living pitheciins. Its estimated body size of approximately 2.0 kg places it within the size range of extant pitheciines. The dental and gnathic morphology of Nuciruptor clarifies several aspects of dental character evolution in Pitheciinae and makes it less likely that the enigmatic Mohanamico hershkovitzi (m. Miocene, Colombia) is a pitheciin. Am. J. Phys. Anthropol. 102:407–427, 1997. © 1997 Wiley-Liss, Inc.  相似文献   

8.
A distal tibia, YGSP 1656, from the early Late Miocene portion of the Chinji Formation in Pakistan is described. The fossil is 11.4 million years old and is one of only six postcranial elements now assigned to Sivapithecus indicus. Aspects of the articular surface are cercopithecoid-like, suggesting some pronograde locomotor activities. However, YGSP 1656 possesses an anteroposteriorly compressed metaphysis and a mediolaterally thick medial malleolus, ape-like features functionally related to orthograde body postures and vertical climbing. YGSP 1656 lacks specializations found in the ankle of terrestrial cercopithecoids and thus Sivapithecus may have been primarily arboreal. Nevertheless, the morphology of this tibia is unique, consistent with other interpretations of Sivapithecus postcranial functional morphology that suggest the locomotion of this ape lacks a modern analog. Based on the limited postcranial remains from S. indicus, we hypothesize that this taxon exhibited substantial body size dimorphism.  相似文献   

9.
A partial right humerus has been recovered from the Early Cretaceous (Albian) Eumeralla Formation at Dinosaur Cove in south-eastern Australia. General morphology, size and the presence of a single epicondylar foramen (the entepicondylar) suggest that the bone is from a mammal or an advanced therapsid reptile. The humerus is similar in size, shape and torsion to the equivalent bone of extant and late Neogene echidnas (Tachyglossidae) but, contrary to the situation in extant monotremes, in which the ulna and radius articulate with a single, largely bulbous condyle, it bears a shallow, pulley-shaped (i.e. trochlear-form) ulnar articulation that is confluent ventro-laterally with the bulbous radial condyle. This form of ulnar articulation distinguishes this bone from the humeri of most advanced therapsids and members of several major groups of Mesozoic mammals, which have a condylar ulnar articulation, but parallels the situation found in therian mammals and in some other lineages of Mesozoic mammals. As in extant monotremes the distal humerus is greatly expanded transversely and humeral torsion is strong. Transverse expansion of the distal humerus is evident in the humeri of the fossorial docodont Haldanodon, highly-fossorial talpids and some clearly fossorial dicynodont therapsids, but the fossil shows greatest overall similarity to extant monotremes and it is possible that the peculiar elbow joint of extant monotremes evolved from a condition approximating that of the fossil. On the basis of comparisons with Mesozoic and Cainozoic mammalian taxa in which humeral morphology is known, the Dinosaur Cove humerus is tentatively attributed to a monotreme. However, several apparently primitive features of the bone exclude the animal concerned from the extant families Tachyglossidae and Ornithorhynchidae and suggest that, if it is a monotreme, it is a stem-group monotreme. Whatever, the animal's true affinity, the gross morphology of its humerus indicates considerable capacity for rotation-thrust digging.  相似文献   

10.
The distal half of a right human humerus (E.898), recovered ex situ in 1925 by Hrdli?ka at the Broken Hill Mine, Kabwe, Zambia, has figured prominently in assessments of Middle Pleistocene Homo postcranial variation and of the phylogenetic polarity and functional anatomy of Pleistocene Homo upper limb morphology. Reassessment of distal humeral features that distinguish modern human and some archaic Homo humeri, especially relative olecranon breadth and medial and lateral pillar thicknesses, confirm previous studies placing it morphologically close to recent humans, as well as possibly to Early Pleistocene Homo. However, it completely lacks stratigraphic context, and there is faunal and archeological evidence for human activity at Broken Hill from the Middle Pleistocene to the Holocene. Given its uncertain geological age and modern human morphology, the Broken Hill E.898 humerus should not be used in analyses of Pleistocene humans until it is securely dated. Am J Phys Anthropol 149:312–317, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

11.
We report here a new fossil primate from the middle Miocene of Argentina. The material consists of isolated teeth, mandibular fragments, and a talus. The fossils were collected in the Collón Cura formation at Cañadón del Tordillo in Neuquén Province. An age of 15.71 ± 0.07 Ma has been reported for the Pilcaniyeu Ignimbrite, which lies just below the paleosols in which the fossils were found. This material is thus the youngest occurrence of fossil primates in Argentina (hitherto documented in the Santacrucian and older land mammal ages) but still is older than the middle Miocene platyrrhine primates from La Venta, Colombia, in particular the pitheciins Nuciruptor and Cebupithecia. The material is recognized as a new genus and species of Pitheciinae, Propithecia neuquenensis. The mesiodistally compressed, high-crowned incisors are specialized and similar to species in the tribe Pithecini and to the nonpitheciin Soriacebus (early Miocene, Patagonia). We rule out a phylogenetic relationship to the latter because of differences in molar morphology. Propithecia does, however, fit well into the pattern of pitheciin evolution, being more derived than the middle Miocene pitheciin Nuciruptor but not as much as another middle Miocene taxon, Cebupithecia. As such, this makes Propithecia the oldest taxon that can be confidently placed within this modern New World monkey subfamily. By analogy with the molar structures and diets of extant platyrrhines, Propithecia has a molar structure consistent with a variety of low-fiber diets ranging from fruit and gum to seeds. Its incisors suggest seed-eating in much the same way as extant pitheciins, like Pithecia. The talus resembles that of Callicebus, suggesting arboreal quadrupedal locomotion. Am. J. Primatol. 45:317–336, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

12.
Abstract:  The heterodont bivalve Sinbadiella pygmaea gen. et sp. nov. is described from the Sinbad Limestone Member (Olenekian, Smithian) of the Lower Triassic Moenkopi Formation of Utah (USA). The new taxon is tentatively assigned to the Lucinidae on the grounds of its external morphology, larval shell morphology and hinge characters. It is the only definite representative of the Superorder Heterodonta in the Olenekian, removing this major clade of bivalves from the long list of Early Triassic Lazarus taxa. Although at least locally very abundant, the new taxon has been overlooked by earlier workers, probably due to its minute size. Dwarfism is a widespread phenomenon in Early Triassic faunas, which has been attributed to ongoing reduction of primary production. If S .  pygmaea was a lucinid, a chemosymbiotic feeding mode can be inferred, which might explain why it was able to thrive in conditions that suppressed filter feeding heterodonts.  相似文献   

13.
Two partial postcranial skeletons from the Lower Muschelkalk (early Anisian) of Winterswijk, The Netherlands, are described in detail. The specimens were assigned to basal Pistosauroidea, presumably to cf. Cymatosaurus or a closely related taxon. Cymatosaurus is currently the earliest member of the Pistosauroidea and is only known from skull material. Taxonomical assignment is based on humerus morphology and histology, and on morphological differences from other Sauropterygia (Nothosauria and Pachypleurosauria).  相似文献   

14.
We reanalyze a hominid talus and calcaneus from Omo dating to 2.2 mya and 2.36 mya, respectively. Although both specimens occur at different localities and times, both tarsals articulate well together, suggesting a single taxon on the basis of size and function. We attribute these foot bones to early Homo on the basis of their morphology. The more modern-like tarsal morphology of these Omo foot bones makes them very similar to a talus from Koobi Fora (KNM-ER 813), a specimen attributed to Homo rudolfensis or Homo erectus. Although the Omo tarsals are a million years younger than the oldest known foot bones from Hadar, both localities demonstrate anatomical differences representing two distinct morphological patterns. Although all known hominid tarsals demonstrate clear bipedal features, the tarsal features noted below suggest that biomechanical changes did occur over time, and that certain features are associated with different hominid lineages (especially the robust australopithecines).  相似文献   

15.
In this report, we present a morphometric comparative study of two Early Pleistocene humeri recovered from the TD6 level of the Gran Dolina cave site in Sierra de Atapuerca, northern Spain. ATD6-121 belongs to a child between 4 and 6 years old, whereas ATD6-148 corresponds to an adult. ATD6-148 exhibits the typical pattern of the genus Homo, but it also shows a large olecranon fossa and very thin medial and lateral pillars (also present in ATD6-121), sharing these features with European Middle Pleistocene hominins, Neandertals, and the Bodo Middle Pleistocene humerus. The morphology of the distal epiphysis, together with a few dental traits, suggests a phylogenetic relationship between the TD6 hominins and the Neandertal lineage. Given the older geochronological age of these hominins (ca. 900 ka), which is far from the age estimated by palaeogenetic studies for the population divergence of modern humans and Neandertals (ca. 400 ka), we suggest that this suite of derived "Neandertal" features appeared early in the evolution of the genus Homo. Thus, these features are not "Neandertal" apomorphies but traits which appeared in an ancestral and polymorphic population during the Early Pleistocene.  相似文献   

16.
The postcranial skeleton of the late Paleocene Arctocyon primaevus is described based on a sub-complete associated specimen. A comparison with arboreal or scansorial and fossorial extant taxa shows that on the forelimb, several features suggest arboreal capabilities, including the development of abductors and adductors, the development of digital flexors, which allows grasping/manipulative ability, as well as the highly mobile articulations, the convex ulna, and the pentadactyl, plantigrade foot. In contrast with the highly mobile joints of the limbs, Arctocyon had a rigid posterior thoracic area, characterized by revolute zygapophyses unknown in extant mammals. The morphology of the most anterior caudal vertebra indicates that the tail was long, powerful, muscular, and rigid at its base, and that it played an important role in locomotion. The morphology of the hind limb is congruent with that of the forelimb, the development of the adductors, flexors, and rotators of the mobile hip joint being emphasized. Although the femoral trochlea is longer and better defined than in highly arboreal taxa, Arctocyon probably moved in a controlled fashion. A comparison with South American borhyaenoids shows that Arctocyon is morphologically more similar to some predator-like Miocene metatherians than to any living mammal. It represents an interesting mix between Prothylacinus and Borhyaena in overall size and proportions, and shows a development of crests and processes of the humerus similar to those of Prothylacinus. Arctocyonidae, which evolved towards incipient saber-toothed canines combined with cheek teeth compatible with an omnivorous diet, and which show a postcranium that is morphologically more similar to carnivorans than to ungulates, represent a mosaic of features that is of particular interest in the evolution of mammals.  相似文献   

17.
Abstract: ‘Totanuslartetianus, Elorius paludicola and ‘Tringagracilis are the three scolopacid birds from the early Miocene of Saint‐Gérand‐le‐Puy described by the French palaeontologist Milne‐Edwards in the 19th century. Since then, no revision of these taxa has been performed. Our re‐examination revealed that not much of the material originally assigned to ‘Totanuslartetianus can be retained within the species. Presumably plesiomorphic features of the humerus – and potentially the coracoid we attributed to this taxon – indicate that it is misplaced in the extant scolopacid genus and may not even belong to the Scolopacidae (sandpipers and allies), and we therefore place it in the new genus Scolopacimilis. Comparisons of the material assigned to Elorius paludicola and ‘Tringagracilis show that they are morphologically similar, both exhibiting distinct scolopacid anatomical features. The latter, however, cannot be referred to the extant taxon Tringa and is classified into the new genus Parvelorius. We further introduce three new species, ?Elorius limosoides sp. nov., and ?Parvelorius calidris sp. nov., which we have tentatively assigned to the extinct scolopacid genera Elorius and Parvelorius, respectively, and Becassius charadriioides gen. et. sp. nov., which, together with Scolopacimilis, display a morphology uncharacteristic for extant Scolopaci. For the first time we have assigned skulls to some of the postcranial elements described in this study. The presence of at least six species of Scolopaci from the early Miocene considerably increases the number of members of the group known from this time.  相似文献   

18.
Here, we report on an isolated pliopithecid M3/ (IPS35028) from locality ACM/C3-B2 (12.0 Ma, MN7) of the late Middle Miocene stratigraphic series of Abocador de Can Mata (ACM, Vallès-Penedès Basin, NE Iberian Peninsula). This tooth is about 0.2 million years older than the remains of Pliopithecus canmatensis (11.8-11.7 ma), recorded from several localities from the ACM series. The unusual occlusal features of IPS35028, together with the lack of homologous material for several pliopithecid species, preclude a precise taxonomic attribution of the C3-B2 specimen, which does not fit the morphology of any known pliopithecid M3/. In particular, although an attribution to P. canmatensis would seem reasonable on the basis of size, identical geographic provenance, and similar age, the morphology of IPS35028 appears too primitive compared to the M1/ and M2/ of the former taxon. Instead, the C3-B2 pliopithecid displays several primitive features shared with the dionysopithecine Dionysopithecus and the pliopithecine Pliopithecus piveteaui. It therefore seems more likely that IPS35028 represents a previously unknown pliopithecid taxon, although a formal taxonomic recognition of its probable distinct status is not advisable, given the scarcity of the currently available material. Alternatively, this taxon might be more closely related to small-bodied African catarrhines (such as dendropithecids). However, the morphology of the ACM specimen is not particularly similar to that of the M3/ of these African taxa. Hence, based on age and geographic provenance, an attribution of IPS35028 to the Pliopithecidae is favored here.  相似文献   

19.
R. Zetter  M. Hesse 《Grana》2013,52(5):285-294
The morphology of pollen tetrads and viscin threads is described in fossil Ericaceae pollen from various Eocene/Oligocene/Miocene localities in Europe (Germany, Austria), North America (eastern U.S.A.), and Asia (eastern China). The typical characters of the tetrad configuration, the exine ornamentation and sculpturing, and especially the viscin thread morphology are extremely similar to or even indistinguishable from that in extant members of Rhododendron. All these pollen morphological features strongly suggest that all the investigated material can be assigned to a modern taxon of the Ericaceae: either to Rhododendroideae or even to Rhododendron itself.  相似文献   

20.
The extinct Southeast Asian primate family Amphipithecidae is regularly cited in discussions of anthropoid origins, but its phylogenetic position remains controversial. In part, the lack of consensus regarding amphipithecid relationships can be attributed to uncertainty regarding the homology of upper molar structures in this group. Here, we describe a virtually pristine upper molar of Pondaungia cotteri from the late middle Eocene Pondaung Formation of Myanmar, which is the first example of a relatively unworn and well-preserved amphipithecid upper molar ever recovered. The distolingual upper molar cusp in this new specimen of Pondaungia appears to be a lingually displaced and enlarged metaconule, rather than a hypocone or pseudohypocone as previous workers have thought. Reassessment of the upper molar morphology of other amphipithecids and putative amphipithecids reveals a very similar pattern in Siamopithecus, Myanmarpithecus and Ganlea, all of which are interpreted as having upper molars showing many of the same derived features apparent in Pondaungia. In contrast, the upper molar morphology of Bugtipithecus diverges radically from that of undoubted amphipithecids, and the latter taxon is excluded from Amphipithecidae on this basis. Phylogenetic analyses of several character–taxon matrices culled from the recent literature and updated to reflect the new information on amphipithecid upper molar morphology yield similar results. Consensus tree topologies derived from these analyses support amphipithecid monophyly and stable relationships within Amphipithecidae. Amphipithecids appear to be stem members of the anthropoid clade.  相似文献   

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