腊玛古猿和西瓦古猿的形态特征及其系统关系——牙齿的形态与比较

禄丰腊玛古猿和西瓦古猿的牙齿有许多性状是一致的,但在犬齿和下前臼齿的形态上则有较大的差别,这些差别可能是两性的差别。它们与现代大猿类相比,表现出与猩猩比较相似,而与大猩猩和黑猩猩差别较大,因而禄丰腊玛古猿和西瓦古猿可能是同一类型的雌雄个体,与猩猩有较近的关系。但另一方面,与南方古猿类的牙齿相比,禄丰腊玛古猿牙齿又显示出较多的相似于南方古猿阿法种和非洲种的性状,而西瓦古猿大的犬齿与所有南方古猿类差别甚大,因此另一种可能性是禄丰腊玛古猿与西瓦古猿是不同的类型,前者是向南方古猿方向进化的早期的人科成员。     

禄丰西瓦古猿和腊玛古猿的关系及其系统地位

本文对十年来采集的禄丰腊玛古猿和西瓦古猿化石进行阶段性研究,对这两类古猿的关系及其系统地位提出进一步的看法:禄丰腊玛古猿和西瓦古猿在形态上表现出同种二形的性质,因此它们是同一个种的雌雄个体,它们的学名被修订为禄丰西瓦古猿(sivapithecuslufengensis);禄丰标本的有些特征不同于同时代的其他古猿,而相似于南方古猿和非洲猿类,因此它们可能是向南方古猿和非洲猿类方向进化的一个代表类型。     

云南禄丰发现的腊玛古猿和西瓦古猿的下颌骨

本文记述在云南禄丰早上新世褐煤层中发现的两个古猿下颌骨化石:即禄丰腊玛古猿(Ramapithecus lufengensis)和云南西瓦古猿新种(Sivapithecus yunnanensis sp.nov.)。鉴于它们在形态上各自显示出接近于人属的早期类型和化石猩猩的性质,作者认为它们可能分别代表人类和猩猩的直系祖先,而我国西南也可能是人类起源的重要地区之一。文中还对腊玛古猿和西瓦古猿的由来及其发展趋势提出了一些初步的看法。     

腊玛古猿和西瓦古猿的形态特征及其系统关系——颅骨的形态与比较

本文通过具体的形态比较指出,禄丰腊玛古猿和西瓦古猿应为同一类型的雌雄个体,它们与现代猩猩比较相似,而与大猩猩和黑猩猩差别较大,因此,它们可看作是猩猩的祖先。猩猩这一支大约是在一千二百万年前开始从人猿超科的进化主干上分化出来的。     

云南西瓦古猿头骨的初步研究

本文对1978年12月在云南禄丰石灰坝煤窑发现的第一个古猿头骨化石作了描述和比较,归属为云南西瓦古猿类型。由于它在形态上保留一些原康修尔猿的性质和显示出较多的相似于猩猩的特征,所以作者认为它可能代表后两者的中间环节。同时,作者又发现这个头骨具有接近于南方古猿粗壮种的性质,因此认为云南西瓦古猿与南方古猿粗壮类型可能有亲缘关系。     

禄丰古人类考察获硕果

云南禄丰是久已闻名于世的化石产地。1975—1976年,我国科学工作者同当地贫下中农一道,在禄丰约一千万年前的上新世褐煤层中,发现了丰富的古猿化石(有二具较完整的下颌骨及百余枚牙齿)和其他哺乳动物化石。古猿化石可分两种:一种属森林古猿类型,可能是现代猩猩的祖先;另一种则与腊玛古猿相接近,是向人类方向发展的过渡类型。这批珍贵的古猿化石的发现,     

云南禄丰古猿化石地点再次发现腊玛古猿头骨——1981年发掘报告

本文记述了1981年10月—12月在云南禄丰古猿化石地点发掘的地层情况以及古猿、其他灵长类化石的初步观察。此次发掘在第3层发现三个腊玛古猿头骨,其中两个为少年个体,在第5层发现具有较完整下颌支的西瓦古猿下颌骨。这些材料的发现有助于确定腊玛古猿的系统地位和西瓦古猿头骨形态的复原。     

根据孢粉推论禄丰腊玛古猿生活时期的自然环境

<正> 前言1975年,云南禄丰石灰坝煤窑中发现了腊玛古猿的牙齿.后经进一步发掘,找到了完整的腊玛古猿下颌骨,以及腊玛古猿、西瓦古猿的牙齿,并采得大量的其他动物化石.腊玛古猿现在被认为是人科的第一个成员,是从猿到人的过渡类型,它可能代表人类     

禄丰发现重要的古猿化石

云南禄丰是久已闻名的化石产地。1975—1977年,我国科学工作者同当地贫下中农一道,在禄丰约一千万年前的上新世褐煤层中,发现了重要的古猿和大量的共生动物化石。1976年11月发现的一个比较完整的古猿下颌骨,由于它的形态特征表现出从猿到人的过渡性质,被确立为腊玛古猿属的一个新种——禄丰腊玛古猿。这一新的发现和研究,对人类起源的基本理论和对理解恩格斯的劳动在从猿到人转变过程中的作用提供了有力的证据。另一个重要的比较完整的古猿下颌骨,属于森林古猿类型,其形态特征表明,它是更新世化石猩猩和现代猩猩的祖先,这就为解决猩猩     

古猿发现史上的新突破

1978年12月16日,在云南省禄丰县石灰坝古猿化石产地,由中国科学院古脊椎动物与古人类研究所和云南省博物馆联合组成的考察队,发现了世界上第一个800万年前的古猿头骨化石。消息一发表,立即在国内外产生广泛的反响。它是怎么被发现的呢?它的发现具有什么样的重大意义呢?大喜日子云南禄丰吉猿化石产地发现于1975年,我们先后于1975年冬和1976年春、冬组织过三期发掘,采集到两个古猿下颌骨和一百多颗牙齿,以及丰富的哺乳动物群化石。对于这两个古猿下颌骨的研究表明,它们是不同的两个属的新种,分别订名为云南西瓦古猿和禄丰腊玛古猿。论文发表以后,引起了国际上学术界很大的重视。     

Why fuse the mandibular symphysis? A comparative analysis

Fused symphyses, which evolved independently in several mammalian taxa, including anthropoids, are stiffer and stronger than unfused symphyses. This paper tests the hypothesis that orientations of tooth movements during occlusion are the primary basis for variations in symphyseal fusion. Mammals whose teeth have primarily dorsally oriented occlusal trajectories and/or rotate their mandibles during occlusion will not benefit from symphyseal fusion because it prevents independent mandibular movements and because unfused symphyses transfer dorsally oriented forces with equal efficiency; mammals with predominantly transverse power strokes are predicted to benefit from symphyseal fusion or greatly restricted mediolateral movement at the symphysis in order to increase force transfer efficiency across the symphysis in the transverse plane. These hypotheses are tested with comparative data on symphyseal and occlusal morphology in several mammals, and with kinematic and EMG analyses of mastication in opossums (Didelphis virginiana) and goats (Capra hircus) that are compared with published data on chewing in primates. Among mammals, symphyseal fusion or a morphology that greatly restricts movement correlates significantly with occlusal orientation: species with more transversely oriented occlusal planes tend to have fused symphyses. The ratio of working- to balancing-side adductor muscle force in goats and opossums is close to 1:1, as in macaques, but goats and opossums have mandibles that rotate independently during occlusion, and have predominantly vertically oriented tooth movements during the power stroke. Symphyseal fusion is therefore most likely an adaptation for increasing the efficiency of transfer of transversely oriented occlusal forces in mammals whose mandibles do not rotate independently during the power stroke.     

Sivapithecus simonsi,a new species of miocene hominoid,with comments on the phylogenetic status of the ramapithecinae

The Ramapithecinae are an extinct, mainly Miocene group of hominoids, whose relationship to modern taxa is disputed. Some regard them as hominids, while others view them as ancestral toPongo,or even as the group ancestral to both hominids and extant apes. In this paper a systematic revision of Ramapithecinae is undertaken. Sivapithecus sivalensis andRamapithecus punjabicus are considered the same species, with the former name having priority. A new Indian species,Sivapithecus simonsi,is recognized. Ramapithecine anatomy is reviewed and compared with that of gracileAustralopithecus, early and middle MioceneProconsul andDryopithecus, and living pongidsPan, Gorilla, andPongo.Ramapithecines are shown to be much more primitive or “ape-like” than some have argued. Anatomical data are evaluated cladistically with several results. Parallel evolution in the jaws, teeth, and facial structure of hominoids appears to be the rule rather than the exception. Bearing this in mind, nevertheless, from the available evidence of anatomy, ramapithecines are cladistically hominids.     

Subnasal alveolar morphology and the systematic position of Sivapithecus

Recent collecting in the Potwar Plateau of Pakistan has produced several new maxillae attributable to Sivapithecus. Since the subnasal region is preserved in most of these specimens, comparisons with early Miocene hominoid and Pliocene hominid maxillae become possible. On the basis of these comparisons, it has become clear that subnasal/premaxillary morphology distinguishes Asian and African hominoids. Ramapithecus and Sivapithecus share with Pongo an "Asian" subnasal pattern. The Proconsul species from the early Miocene of western Kenya and Australopithecus afarensis from the Hadar Formation of Ethiopia present two subsets of an "African" subnasal pattern. We think it likely that Ramapithecus and Sivapithecus represent a lineage that postdates the last common ancestor of African and Asian hominoids.     

The juvenile mandible of<Emphasis Type="Italic">Lufengpithecus</Emphasis>

The juvenile mandible ofLufengpithecus lufengensis (PA869) discovered in 1980 at back to latest Miocene lignite rich deposit in Shihuiba Village, Lufeng County, Yunnan Province in southwest of China is described in this study. The specimen was compared with the juvenile mandibles ofSivapithecus, Australopithecus, earlyHomo and extant great apes. Some characteristics of the juvenile mandible ofLufengpithecus indicate that the proportional relation between the length, the height and the thickness of the mandibular corpus are very similar to those of the adult mandible of same species. This Lufeng juvenile mandible is of a 3–3.5 years old female individual.     

The nature of the transition in the dental mechanism from pongids to hominids

Many recent discoveries of Ramapithecus, and of probably ground-living dryopithecines, Dryopithecus (subgenus Sivapithecus), clarify the nature of the transition of the dental mechanism from that of pongids to the hominid stage with reduced canines and flattened cheek teeth with thick enamel.Faunal correlation with potassium/argon dated sites indicates that Sivapithecus and Ramapithecus appeared in the Old World about the same time, approximately 13 million years ago. The thickened molar enamel of these hominoids suggests a terrestrial adaptation in both groups, probably resulting from climatic changes. This adaptation was not necessarily a unique event in the ancestry of the two genera, for species of the two seem to have been different sizes when the change was made.New Ramapithecus finds come from Pyrgos, near Athens, from Çandir in Anatolia, and from Rudabánya, Hungary. At the latter site various specimens preserve all upper and lower teeth in place, while the Çandir and Pyrgos mandibles give important new information about symphyseal structure and orientation, as well as about arcade arrangement. The Rudabánya finds confirm, as do the others, marked facial foreshortening, relatively orthal incisors, anteriorly abbreviated mandible and canine reduction in Ramapithecus. The dental mechanics of Ramapithecus suggested from earlier described finds recovered in the Siwalik deposits of India and Pakistan, as well as at Fort Ternan, Kenya are clarified by the finds from Athens, Anatolia, and Hungary. Like Australopithecus, Ramapithecus mandibles have well-developed double transverse, shallow but transversely thick horizontal rami and anteriorly shifted, vertically oriented, deep ascending branches. These addes resemblances increase the probability that Ramapithecus is in or near the ancestry of Australopithecus and other hominids.     

On the adaptive pattern of "Ramapithecus".

A reconstruction of the adaptive pattern of the Miocene hominoid "Ramapithecus," supported by comparative data and morphological comparisons, is presented. It is based upon the completely known dentition, inferior portion of the face, and on the paleoecology and geographic distribution of "Ramapithecus" bearing deposits. The known adaptive and morphological patterns of the "Ramapithecus" species are almost indistinguishable from those of the contemporary species of Sivapithecus, which has taxonomic priority. The "Ramapithecus" species are therefore referred to Sivapithecus, a dryopithecine genus which apparently radiated throughout Eurasia and Africa during the Middle Miocene.