甘肃庆阳上新世鬣狗科化石

本文记述的标本,是桑志华1920年采集而未研究过的,共有头骨与牙床50多件。标本中可以归入旧属种的有四类,其种名订正后为:Adcrocuta eximia variabilis,Ictitherium robustumgaudryi,I.wongii 和 Ictitherium hipparionum hyaenoides.材料中还包括一个新属,Palinhyaena和三个新种:P.reperta,P.imbricata 和 Lycyaena spathulata,Palinhyaena 极可能就是久寻未见的现生鬣狗在上新世中期的直系祖先类型。它在我国的发现对了解鬣狗科的进化发展及科内的分类提供了重要的新资料。     

内蒙古中新世通古尔组 Tungurictis(Carnivora:Hyaenidae)的新材料

斯氏通古尔鼬 (Tungurictisspocki)是 1 939年Colbert描述的一个采自内蒙古中中新世通古尔组的小型食肉类的新属、新种。他最初认为通古尔鼬属于灵猫科 ,但最近Hunt( 1 989)及Hunt和Solounias( 1 991 )提出通古尔鼬具有一些鬣狗科耳区的特征 (如水平方向的听泡隔板等 )但缺少典型鬣狗科强壮的用来咬碎骨骼的前臼齿。Werdelin和Solounias( 1 991 )对鬣狗科分支系统的研究也进一步证实通古尔鼬实际上是一种鬣狗科较为原始的成员。因此通古尔鼬成为研究鬣狗科初期演化关系的重要一环。Tungurictisspocki的正型标本 (AMNH 2 660 0 )是一件相当完整的头骨 ,但这是美国自然历史博物馆第三次中亚考查团在狼营地点 (WolfCamp)获得的惟一标本。缺少下颌骨和非常关键的下裂齿对于研究鬣狗科关系总是一件憾事。因此在通古尔台地南缘首次发现的出自同一个体的斯氏通古尔鼬上、下颌骨 ,对加深该种形态特征的认识和对鬣狗科系统关系的研究都具有一定意义。新发现的材料 (IVPPV 1 3784)包括很可能属同一个体头骨的前半部分以及下颌骨 ,并保存了P3～M2及m1～m2。V 1 3784采自内蒙古苏尼特左旗IVPP 346地点西 1 .5km(美国自然历史博物馆中亚考查团推饶木诺尔地点TairumNorlocality ,又称南营地SouthCamp) ,属通古尔组下部     

陕西蓝田晚中新世食肉类

陕西省蓝田地区灞河组与蓝田组产出了大量的古哺乳动物化石。其中,晚中新世哺乳动物化石序列为认识该地区自然环境的变化提供了重要的依据。详细描述和研究了其中的食肉类化石。计有鬣狗科3种(Ictitherium viverrinum、Hyaenictitherium cf.H.wongii、Adcrocuta eximia)和猫科2种(cf.Metailurus major与cf.Metailurus parvulus)。在下部的灞河组与上部的蓝田组界线附近,食肉类动物群落组成发生了改变,但引起这种改变的原因仍有待进一步研究确定。     

陕西府谷晚中新世巨鬣狗(Dinocrocuta gigantea)(食肉目：鬣狗科)颅基部形态研究（英文）

巨鬣狗(Dinocrocuta gigantea)之前曾因其特殊的乳齿特征而被排除于鬣狗科之外,而归入单独的中鬣狗科(Percrocutidae)。对一产自陕西府谷的巨鬣狗头骨后部进行了扫描和内部结构重建,详细描述了颅基部内外形态,并与其他猫形类进行了对比。巨鬣狗在颅基部显示出了鬣狗科的典型模式,支持将其置于鬣狗科之内的传统观点,而中鬣狗科的有效性则值得怀疑。巨鬣狗的颅基部还具有很多独特特征,暗示其可能是鬣狗科的一个早期旁支。     

我国更新世两属鬣狗(Hyaena,Crocuta)的关系与分类

多数学者认为,更新世的两属鬣狗与现生两属鬣狗相比,化石Hyaena不同于现生Hya-ena,而与Crocuta更为相近。本文结合近年来采集的新材料的研究,进一步论证了化石Hya-ena与Crocuta的密切关系,并且赞成把我国的Hyaena licenti和H.sinensis的属名订正为Pachycrocuta。     

山顶洞101号男性头骨的三维颅面复原

山顶洞101号头骨化石是东亚地区保存最为完整的化石之一,是探讨东亚地区现代人起源的重要研究材料。本文依据数据集中现生人的面部软组织平均分布,提出了计算机三维颅面复原方法,实现了101号头骨生前面貌的预测复原。主要包括三个步骤：首先使用CT完成了101号男性头骨和下颌骨仿制模型的三维重建。然后,利用计算机技术将现生人的面部软组织分布作为101号头骨的面部软组织分布,实现了颅面虚拟复原,并采用手工绘画技巧再现了复原面貌的形态特征。最后,提出了一种基于面部软组织分布和面貌统计形状模型的形态分析方法,实现了颅面复原结果的评估。山顶洞101号头骨的复原面貌具有头部较长、额头前倾、眉弓粗壮等特征,与101号头骨的几何形态基本一致。该技术再现了更新世晚期人类的脑颅及面部的形态特征,为古人类颅面复原的研究提供了技术支持和参考资料。     

陕西府谷巨鬣狗的新材料

陕西府谷老高川发现的Dinocrocutagigantea化石是目前我国该属最完整、最丰富的材料,包括头骨、上下颌、牙齿及一些肢骨。Dinocrocutagigantea是一类头骨相当粗策的食肉动物,但肢骨除个体大小与现代鬣狗的不同外,各部比例彼此相当,头部特化无疑是其进化过程中的适应表现。该属的地质时代,多数研究者认为是Vallesian期的典型种类,但府谷老高川含化石层古地磁年代初步测定表明,该层的绝对年龄在7─8百万年之间,这是一个值得注意的问题。     

新发现的长吻型离龙(双孔亚纲：离龙目)幼年个体——袖珍蒙山龙，兼论新离龙类的个体发育（英文）

离龙是一类生活在中侏罗世至中新世的半水生掠食性动物。白垩纪早期,部分离龙类演化为与现生鳄鱼形态类似的大型长吻爬行动物,称为新离龙类。报道了来自山东省下白垩统蒙阴组的一长吻型离龙新种——袖珍蒙山龙(Mengshanosaurus minimus),正型标本头骨全长仅35 mm,是迄今为止发现的最小新离龙类个体。根据未完全骨化的颅腔和额骨-顶骨间尚存未愈合的圆孔,推测蒙山龙正型标本为一幼年个体。系统发育分析显示,蒙山龙属于新离龙类,具有单个外鼻孔,单一鼻骨和下颞孔开放等新离龙类的共有衍征。在新离龙类内部,蒙山龙分类位置较为基干,为伊克昭龙属(Ikechosaurus)、车尔龙属(Tchoiria)、西莫多龙属(Simoedosaurus)和鳄龙属(Champsosaurus)组成的支系的姐妹群。蒙山龙区别于其他新离龙类的特征包括泪孔位于前额骨与泪骨之间,以及增大的腭面齿(宽度超过上颌齿的1/3)。蒙山龙具有长吻和紧密排列的尖利牙齿,推测离龙类幼体与现生鳄类幼体食性类似,以水生昆虫和无脊椎动物为食。现生鳄类在发育过程中,吻部的形态常发生改变,牙齿也会从尖细的形状转向圆钝;而蒙山龙的吻部和牙齿的形态与已知大体型的成体新离龙类没有明显区别,这说明相较于现生鳄类,新离龙类在发育过程中生态位的变化并不显著。     

内蒙古三盛公渐新世古鼬(食肉目,古鼬科)新材料及系统发育关系分析

古鼬属(palaeogale)由H.von Meyer于1846年建立,欧亚大陆以及北美的晚始新世一中新世地层中均有报道。但受化石标本以及研究程度的限制,古鼬的分类位置问题一直存在争议,曾被分别归入鼬科(Mustelidae)、古灵猫科(Viverravidae)、猫科(Felidae)、古鼬科(Palaeogalidae)和猫型亚目(Feliformia)科未定等。内蒙古三盛公地区新发现了5件古鼬标本,其中IVPP V 19325(包括属于同一个体的一件残破头骨、一对近乎完整的下颌以及一些椎体和肋骨)是目前为止亚洲发现的保存最完好的标本。本文详细描述了这些新材料,并基于新材料,结合前人的图版描述,提取了古鼬的形态学性状特征用于系统发育关系分析。参考Wesley-Hunt and Flynn(2005)的系统发育关系分析,选用了共计42个类群的100个性状特征进行了分析。此外,对12个现生类群的6个基因(细胞核基因TR-i-I,TBG和IRBP;线粒体基因ND2,CYTB和12S rRNA),共计5893个碱基对进行的分子系统发育关系分析,帮助完善了古鼬的形态学系统发育关系分析结果。50%多数合意树的结果显示古鼬与鼬科及古灵猫科均无明显的亲缘关系,而是位于猫型亚目基干位置,代表了猫型亚目下一个原始的支系,可被归入古鼬科(Palaeogalidae)。同时,还厘定了古鼬科的鉴定特征。未来还需要更完整的性状数据,尤其是耳区的性状特征,来完善古鼬的系统发育关系分析。     

河南栾川孙家洞遗址出土的穿孔标本北大核心CSCD

孙家洞遗址初步测年为40万年左右,出土了少量石制品、古人类牙齿以及大量动物化石,其中一件骨骼标本存在非常规整的穿孔,其整体形态和大小与人工穿孔比较相似。通过系统的宏观观测与显微镜下分析,并与已明确性质的考古标本(自然穿孔和人工穿孔标本)和实证材料(现代鬣狗洞发掘出土材料)进行对比后发现,孙家洞遗址出土的穿孔标本与食肉类啃咬、甲虫类啮食以及人工造成的穿孔标本存在明显差异,而具备了被鬣狗胃酸腐蚀标本的所有典型特征。     

New materials of Dinocrocuta (Percrocutidae, Carnivora) from Lantian, Shaanxi Province, China, and remarks on Chinese Late Miocene biochronology

New materials from the middle part of the Bahe formation are described as Dinocrocuta gigantea. Review of the species reveals that it is derived in the evolutionary lineage of Dinocrocuta, and biochronologically later than Vallesian records from Turkey. The only possibly related Vallesian species from China is Crocuta gigantea xizangensis from Biru, Tibet, which may prove to be conspecific with D. senyureki. Based on the mammalian faunal sequence from Lantian, and with reference to Red Clay paleomagnetic data, the duration of D. gigantea in China should be later late Miocene, rather than the previously postulated early late Miocene (Vallesian equivalent) age.     

The flora of the early Miocene Brandon Lignite, Vermont, USA. VIII. Caldesia (Alismataceae)

Caldesia, a genus of aquatic monocotyledons, is represented by four living species, which are widely distributed in the temperate and tropical Old World. The genus has an extensive Oligocene through Pleistocene fossil record in Eurasia. We survey the morphology of the extant and fossil fruits of the Alismataceae, and provide a detailed review of the morphology and anatomy of living and fossil Caldesia fruits. The latter exhibit substantial similarity, making the recognition of separate species on the basis of fruit morphology difficult. We erect the new species Caldesia brandoniana from the Early Miocene Brandon Lignite of Vermont primarily on the basis of its geographic isolation; careful revision of all fossil fruiting material of Caldesia might require placement of the Brandon specimens in a more inclusive form species. Together with leaves of Caldesia from the Miocene Clarkia flora of Idaho, this occurrence indicates that Caldesia was in the New World as recently as the Early Miocene.     

Examining affinities of the Taung child by developmental simulation

As a well-preserved juvenile and the type specimen of Australopithecus africanus, the Taung child figures prominently in taxonomic, ontogenetic, and phylogenetic analyses of fossil hominins. Despite general agreement about allocation of Sterkfontein and Makapansgat fossils to this species, limited morphological comparisons have been possible between these adult specimens and the juvenile Taung. Here, we used developmental simulation to estimate the adult form of the Taung child, and directly compare its morphology to that of other fossil hominins. Specimens were represented by 50 three-dimensional landmarks superimposed by generalized Procrustes analysis. The simulation process applied developmental trajectories from extant hominine species to the Taung fossil in order to generate its adult form. Despite differences found in the developmental patterns of these modern species, simulations tested on extant juveniles-transforming them into "adults" using trajectories from other species-revealed that these differences have negligible impact on adult morphology. This indicates that morphology already present by occlusion of the first permanent molar is the primary determinant of adult form, thereby supporting use of extant trajectories to estimate the morphology of an extinct species. The simulated Taung adult was then compared to other adult fossils. As these comparisons required assumptions about the pattern and magnitude of developmental change, additional analyses were performed to evaluate these two parameters separately. Results of all analyses overwhelmingly rejected the possibility that the Taung child was a juvenile robust australopith, but were consistent with the hypothesis that the Taung and Sterkfontein fossils are conspecific. Between Sts 5 and Sts 71, the latter is more likely to resemble the adult form of the Taung child.     

Evolutionary Patterns among Living and Fossil Kogiid Sperm Whales: Evidence from the Neogene of Central America

Kogiids are known by two living species, the pygmy and dwarf sperm whale (Kogia breviceps and K. sima). Both are relatively rare, and as their names suggest, they are closely related to the sperm whale, all being characterized by the presence of a spermaceti organ. However, this organ is much reduced in kogiids and may have become functionally different. Here we describe a fossil kogiid from the late Miocene of Panama and we explore the evolutionary history of the group with special attention to this evolutionary reduction. The fossil consists of cranial material from the late Tortonian (~7.5 Ma) Piña facies of the Chagres Formation in Panama. Detailed comparison with other fossil and extant kogiids and the results of a phylogenetic analysis place the Panamanian kogiid, herein named Nanokogia isthmia gen. et sp. nov., as a taxon most closely related to Praekogia cedrosensis from the Messinian (~6 Ma) of Baja California and to Kogia spp. Furthermore our results show that reduction of the spermaceti organ has occurred iteratively in kogiids, once in Thalassocetus antwerpiensis in the early-middle Miocene, and more recently in Kogia spp. Additionally, we estimate the divergence between extant species of Kogia at around the late Pliocene, later than previously predicted by molecular estimates. Finally, comparison of Nanokogia with the coeval Scaphokogia cochlearis from Peru shows that these two species display a greater morphological disparity between them than that observed between the extant members of the group. We hypothesize that this reflects differences in feeding ecologies of the two species, with Nanokogia being more similar to extant Kogia. Nanokogia shows that kogiids have been part of the Neotropical marine mammal communities at least since the late Miocene, and gives us insight into the evolutionary history and origins of one of the rarest groups of living whales.     

亚洲土著类群硅藻鼠科的演化

硅藻鼠科是仅分布于亚洲的啮齿类类群,头骨具豪猪型咬肌结构,下颌则为松鼠型。该类群代表了一个从梳趾鼠类分化出的区域性支系,虽与豪猪次目相近,但并不是它的成员。最早的硅藻鼠化石记录发现于Baluchistan渐新世陆相地层中,稍晚的记录发现于南业晚渐新世。印度次大陆连续的地层为该科的演化历史提供了主要的化石依据。早中新世晚期至中中新世,硅藻科化石也发现了泰国、中国以及日本。其后的硅藻鼠种类少且鲜有化石记录。晚中新世早期在巴基斯坦有一个种,中国南部晚中新世也可能有一个种。尽管在最早的化石地点发现的标本较多,但其后的时段内除泰国李盆地外化石并不丰富,这指示了其特殊的生活习性或其生活区域化石保存的偏差。已知的化石记录并没有指示出该类群的多样性,也可能是缺少石化作用的结果。硅藻鼠类在水系外围区域延续生存与最近在老挝中部多岩石地带发现的现生Laonastes也是一个硅藻鼠的假设相一致。     

Endocranial morphology of Pygoscelis calderensis (Aves,Spheniscidae) from the Neogene of Chile and remarks on brain morphology in modern Pygoscelis

The endocranial anatomy of Pygoscelis calderensis, a fossil species from the Bahía Inglesa Formation (Middle Miocene–Pliocene) of Chile, South America, was described through CT scans. Reconstructions of the fossil P. calderensis and endocasts for the living Pygoscelis adeliae, and Pygoscelis papua are provided here for the first time. Comparisons with the extant congeneric species P. adeliae, Pygoscelisantarctica and P. papua indicate that the morphological pattern of the brain and inner ear of the extant pygoscelids has been present already in the Middle Miocene. The neurological morphology suggests that the paleobiology of the extinct form would have been similar to the extant species. It was probably true for diet, feeding behaviour and diving kinematics.     

Molecular systematics of the Hyaenidae: relationships of a relictual lineage resolved by a molecular supermatrix

The four extant species of hyenas (Hyaenidae; Carnivora) form a morphologically and ecologically heterogeneous group of feliform carnivorans that are remnants of a formerly diverse group of mammalian predators. They include the aardwolf (Proteles cristatus), a termite-feeding specialist, and three species with a craniodental morphology adapted to cracking the bones of prey and/or carcasses, the spotted hyena (Crocuta crocuta), brown hyena (Parahyaena brunnea), and striped hyena (Hyaena hyaena). Hyenas have been the subject of a number of systematic studies during the last two centuries, due in large part to the extensive fossil record of the group, with nearly 70 described fossil species. Morphological studies incorporating both fossil and living taxa have yielded different conclusions regarding the evolutionary relationships among living hyenas. We used a molecular supermatrix comprised of seven nuclear gene segments and the complete mitochondrial cytochrome b gene to evaluate phylogenetic relationships among the four extant hyaenid species. We also obtained sequence data from representative species of all the main families of the Feliformia (Felidae, Herpestidae, and Viverridae) to estimate the sister group of the Hyaenidae. Maximum parsimony and maximum likelihood analyses of the supermatrix recovered identical topologies. Furthermore, Bayesian phylogenetic analyses of the supermatrix, with among-site rate variation among data partitions parameterized in three different ways, also yielded the same topology. For each phylogeny reconstruction method, all but two nodes received 100% bootstrap or 1.00 posterior probability nodal support. Within the monophyletic Hyaenidae, Parahyaena and Hyaena were joined together, with Crocuta as the sister to this clade, and Proteles forming the most basal lineage. A clade containing two species of mongoose (core Herpestidae) plus Cryptoprocta ferox (currently classified in Viverridae) was resolved as the sister group of Hyaenidae. The pattern of relationships among the three bone-cracking hyaenids (Crocuta, Hyaena, and Parahyaena) is incongruent with recent cladistic assessments based on morphology and suggests the need to reevaluate some of the morphological characters that have been traditionally used to evaluate relationships among hyenas. Divergence time estimates based on a Bayesian relaxed molecular clock indicates that hyaenids diverged from their feliform sister group 29.2 MYA, in the Middle Oligocene. Molecular clock estimates also suggest that the origin of the aardwolf is much more recent (10.6 MYA) than that implied by a cladistic analysis of morphology ( approximately 20 MYA) and suggests that the aardwolf is possibly derived from a bone and meat eating lineage of hyaenids that were present in the Late Miocene. [Hyaenidae; phylogeny; cytochrome b; nuclear gene segments; Proteles; Crocuta; Hyaena; Parahyaena.].     

Sexual dimorphism in Laccopithecus robustus, a late miocene hominoid from China

Laccopithecus robustus is a siamang-sized fossil ape from the Miocene site of Lufeng, China. The species is known from a partial cranium, numerous mandibles, and scores of isolated teeth. This species shows striking dental similarities to Pliopithecus from the Miocene of Europe and a number of cranial similarities to extant gibbons. Laccopithecus differs from extant gibbons and resembles other fossil and extant apes in showing marked sexual dimorphism in the size and shape of the canines and anterior lower premolars. Evidence for sexual differences in either the size or shape of other teeth is less clear. There is some evidence for a sexual size dimorphism based on the variability of molar teeth.     

The anatomy of Dolichocebus gaimanensis, a stem platyrrhine monkey from Argentina

Dolichocebus is known from the type skull encased in a concretion, numerous isolated teeth, parts of two mandibles, and a talus. The specimens come from the Trelew Member (early Miocene, Colhuehuapian South American Land Mammal Age) of the Sarmiento Formation near the village of Gaiman, Chubut Province, Argentina, dated to about 20Ma. We describe all Dolichocebus fossil material using conventional surface anatomy and micro-CT data from the cranium. The new material and newly imaged internal anatomy of the skull demonstrate that anatomical characters hitherto supposed to support a phyletic link between Dolichocebus and either callitrichines (marmosets, tamarins, and Callimico) or Saimiri (squirrel monkeys) are either indeterminate or absent. To more fully explore the phyletic position of Dolichocebus, we undertook a comprehensive phylogenetic analysis. We examined 268 characters of the cranium and dentition of 16 living platyrrhine genera, some late Oligocene and early Miocene platyrrhines, Tarsius, some Eocene and Oligocene stem anthropoids, and several extant catarrhines. These analyses consistently indicate that Dolichocebus is a stem platyrrhine, as are late Oligocene Branisella and early Miocene Tremacebus, Soriacebus, and Carlocebus. Platyrrhine evolution often is conceived of as a single ancient adaptive radiation. Review of all available phyolgenetic data suggests a more layered evolutionary pattern, with several independent extinct clades filling modern platyrrhine niche space, and modern platyrrhine families and subfamilies appearing over a nine-million-year interval in the Miocene. The outcome of these analyses highlights the pervasiveness of homoplasy in dental and cranial characters. Homoplasy is a real evolutionary phenomenon that is present at all levels of biological analysis, from amino-acid sequences to aspects of adult bony morphology, behavior, and adaptation.     

Micropithecus clarki, a small ape from the Miocene of Uganda.

Micropithecus clarki, from Miocene sediments of Napak, Uganda, is the smallest known hominoid primate, living or fossil. In facial morphology it is very similar to extant gibbons. Dentally, it is most similar to the small apes from the Miocene of Kenya, Dendropithecus and Limnopithecus. All of the apes from the early Miocene of East Africa seem to represent a single phyletic group that could be easily derived from the Oligocene apes known from the Fayum of Egypt. Pliopithecus from the Miocene of Europe is more closely allied with the Oligocene radiation than with the later East African radiation.