广西南宁渐新世基于咽齿的鲤亚科一新属

记述了产自广西南宁盆地渐新世早—中期的鲤科鲤亚科一新属种——伍氏南宁鲤(+Nanningocyprinus wui gen.et sp.nov).化石材料包括一些咽喉骨和咽齿.这些咽喉骨和咽齿的以下特征组合明显不同于其他鲤科鱼类:齿式-3·2·1,主行第一枚咽齿大小是第二枚的3～4倍,第二枚咽齿及第二行第一枚咽齿咀嚼面上各仅有一条沟纹,咽骨前角很发育.该属种的发现进一步证明鲤亚科是鲤科中较早的分支,中国南方很有可能是鲤亚科的起源和分化中心.     

Sex determination of the Early Cretaceous clam shrimp Eosestheria middendorfii (Yixian Formation,China)

Clam shrimps have been recognized as a key group for the study of reproductive system evolution, owing to the diversity of sexual systems in extant members. However, there are comparatively little data on fossil taxa. In this study, we reveal the sexual system of the Early Cretaceous clam shrimp Eosestheria middendorfii (Yixian Formation, China). This is the first study that restricts the analysis to a single cohort, minimizing the otherwise considerable impact of ecophenotypic variation within this species. In addition, the presence of egg clutches, which identifies some individuals as either female or hermaphroditic, serves as an independent indicator for sex prior to the statistical treatment of the data. Obligate sexuality (‘dioecy’) is the inferred reproductive system for E. middendorfii and sexual dimorphism accounts for about 10% of the adult shape variation. Carapace shape variation resulting from malformation and deformation is more pronounced than the underlying sexual dimorphism. Subtle sexual dimorphism, smaller and slightly more elongate females, lateral egg clutches, and egg diameters of about 140 μm indicate that E. middendorfii is closely allied with the extant family Cyzicidae.     

The paleoanthropology of Hadar,Ethiopia

Field research at the fossil-bearing deposits in the Afar Depression began in the 1970s. Prior to this, hominin fossils older than 3.0 Mya consisted of only a handful of fragments. During Phase I, the International Afar Research Expedition to Hadar, Ethiopia collected some 240 fossil hominins from Hadar over a time range of 3.0–3.4 Mya. Along with hominin fossils from Laetoli, they were deemed a new species, Australopithecus afarensis. This taxon was posited as the last common ancestor to robust Australopithecus and the Homo lineage in eastern Africa. Phase II research under the Hadar Research Project has added strength to the Phase I results, including the first association of a Homo fossil with stone tools at 2.4 Mya. This presentation is a cursory synopsis of the importance and implications of the hominin fossils recovered at Hadar during over the last 34 years.     

A new hawker dragonfly from the Middle Jurassic of China (Odonata: Aeshnoptera)

A new genus and species Linqibinia panae of paracymatophlebiid hawker dragonfly is described from the Middle Jurassic Haifanggou Formation (Inner Mongolia, China). Previously only known from Karatau in Kazakhstan, the discovery of another member of this family extends its range across Central Asia. It confirms that the Aeshnoptera was among the most diverse odonatan clades during the Middle-Late Jurassic.     

Precambrian animal life: Taphonomy of phosphatized metazoan embryos from southwest China

Phosphatized fossils from the Neoproterozoic Doushantuo Formation have provided valuable insight into the early evolution of metazoans, but the preservation of these spectacular fossils is not yet fully understood. This research begins to address this issue by performing a detailed specimen-based taphonomic analysis of the Doushantuo Formation phosphatized metazoan embryos. A total of 206 embryos in 65 thin sections from the Weng'an Phosphorite Member of the Doushantuo Formation were examined and their levels of pre-phosphatization decay estimated. The data produced from this examination reveal a strong taphonomic bias toward earlier (2-cell and 4-cell) cleavage stages, which tend to be well-preserved, and away from later (8-cell and 16-cell) cleavage stages, which tend to exhibit evidence for slight to intense levels of organic decay. In addition, the natural abundances of these embryos tend to decrease with advancement in cleavage stage, and no evidence of more advanced (beyond 16-cell) cleavage stages or eventual adult forms were found in this study. One possible explanation for this taphonomic bias toward early cleavage stages is that later cleavage stages and adult forms were more physically delicate, allowing them to be more easily damaged during burial and reworking, allowing for more rapid decay. The spectacular preservation of these embryos was probably aided by their likely internal enrichment in phosphate-rich yolk, which would have caused their internal dissolved phosphate levels to reach critical levels with only miniscule organic decay, thereby hastening phosphatization. If internal sources of phosphate did indeed play a role in the phosphatization of these embryos, it may explain their prolific abundance in these rocks compared to other phosphatized fossils as well as indicating that metazoans lacking such internal phosphate sources were likely much more difficult to preserve. The phosphatic fossils of the Doushantuo Formation, therefore, provide an indispensable, yet restricted, window into Neoproterozoic life and metazoan origins.     

Histological structure of the cancellous bone layer in Bothriolepis canadensis (Antiarchi, Placodermi)

The Placodermi are extinct basal gnathostomes which had extensive dermal and perichondral bone, but which lacked the endochondral bone which characterizes the more derived bony fishes. Thin sections of bone from a specimen of the antiarch placoderm Bothriolepis canadensis, from the Escuminac Formation (Frasnian, Upper Devonian), Québec, Canada, reveal that part of the cancellous layer in its dermal and endoskeletal bone formed from perichondral bone trabeculae growing around cartilage spheres. The resultant structure mimics that of osteichthyan endochondral bone. The layout and dimensions of this polygonal mosaic patterning of the bone trabeculae and flattened cartilage spheres resemble those of the prismatic layers of calcified cartilage in chondrichthyans. If the lack of endoskeletal bone in chondrichthyans is a derived character, then the structure identified in B. canadensis could represent a 'template' for the formation of prismatic calcified cartilage in the absence of bone.     

A new choristodere (Reptilia: Diapsida) from the Lower Cretaceous of western Liaoning Province, China, and phylogenetic relationships of Monjurosuchidae

The publication of the scientific name Monjurosuchus splendens in 1940 documented the first tetrapod fossil of the later world-renowned Jehol Biota. For more than half a century since this discovery, however, Monjurosuchus has remained as a monotypic genus of the family Monjurosuchidae, and the relationships of the family with choristoderes have not been correctly recognized until quite recently. In this paper, a new monjurosuchid is named and described based on a nearly complete skull and postcranial skeleton from the Early Cretaceous Chiufotang Formation exposed near Chaoyang, western Liaoning Province, China. This new material documents the first occurrence of monjurosuchid choristoderes outside the type Lingyuan area, and extends the geological range of the family from the Yixian Formation to the younger Chiufotang Formation. Cladistic analyses were conducted with inclusion of monjurosuchids, and the results support the placement of the family Monjurosuchidae as a primitive clade outside the Neochoristodera. A new classification scheme is proposed for choristoderes on the basis of the recovered phylogenetic framework of the group.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 145 , 427–444.     

松辽盆地三肇地区泉头组三段上部介形类化石的指相意义

松辽盆地三肇地区白垩系下统泉头组三段上部(杨三组—杨一组)以大套的紫红、红色砂、泥岩沉积为主,在紫红色泥岩中含有较丰富、完整的介形类及其它门类化石。以往认为,这套以红色为基调的地层属河流相沉积。对其中介形类等化石的古生态、埋藏特征及丰度变化的研究表明,该地层的沉积环境应为浅水湖泊环境,而非河流等水上环境。湖相沉积自杨三组就已存在,向上分布范围不断扩大,反映了湖泊水域面积呈现逐渐扩大的趋势。     

浙江桐庐早二叠世船山组介形类化石

研究报道的介形类化石系采自浙江省桐庐县瑶林镇沈村剖面早二叠世船山组,计14 属4 亚属22 种,包括4新种和4未定种。其中12属4亚属和19种产自船山组第三段,并被归为Hollinella(Praehollinella) ema ciata Basslerella ola 组合,代表早二叠世船山世隆林期。牙形刺化石主要产自船山组第一段,带化石Streptogna thodus elegantulus 及其共生的其它牙形刺化石,指明船山组第一段的时代为中、晚卡西莫夫期到早格泽里期。根据介形类动物群生态组合和岩石特征,推测船山组第三段是在温暖的近岸浅水且为低能的开阔海环境下沉积的。     

热河生物群络新妇科化石新发现(蜘蛛目,络新妇科)

记述产自中国辽西的蜘蛛化石1新种:辽宁白垩园蛛Cretaraneus liaoningensis Cheng,Menget Wang,sp.nov.,是Cretaraneus属在中国的首次发现。同时对北票园蛛Araneus beipiaoensis Chang,2004的特征进行补充描述。标本均采自辽宁省凌源市大王杖子早白垩世义县组中。