Speciation of the genus Arthricocephalus Bergeron, 1899 (Trilobita) from the late Early Cambrian and its stratigraphic significance

The genus Arthricocephalus Bergeron, 1899 is revised, and Halipanktos Balker & Peel, 1997 is suggested here as a senior synonym. The subgenus Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974 is considered as a separate genus. Of the 20 previously assigned species of Arthricocephalus (Arthricocephalus) Bergeron, 1899, Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974, Arthricocephalus (Euarthricocephalus) Ju, 1983 are lumped into eight species. The speciation trend of Arthricocephalus and Arthricocephalites is demonstrated based on their stratigraphic occurrences. It not only enhances the resolution of the biostatigraphic zonation in the uppermost Lower Cambrian, but also represents a potential candidate to define the Duyunian stage. The base of the stage is suggested at the first appearance datum (FAD) of Arthricocephalus chauveaui Bergeron, 1899 within the evolutionary lineage from Ar. jiangkouensis Yin in Yin & Li,1978 to Ar. chauveaui in a global scale.     

Speciation of the genus Arthricocephalus Bergeron, 1899 (Trilobita) from the late Early Cambrian and its stratigraphic significance

The genus Arthricocephalus Bergeron, 1899 is revised, and Halipanktos Balker & Peel, 1997 is suggested here as a senior synonym. The subgenus Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974 is considered as a separate genus. Of the 20 previously assigned species of Arthricocephalus (Arthricocephalus) Bergeron, 1899, Arthricocephalus (Arthricocephalites) Chien & Lin in Lu et al., 1974, Arthricocephalus (Euarthricocephalus) Ju, 1983 are lumped into eight species. The speciation trend of Arthricocephalus and Arthricocephalites is demonstrated based on their stratigraphic occurrences. It not only enhances the resolution of the biostatigraphic zonation in the uppermost Lower Cambrian, but also represents a potential candidate to define the Duyunian stage. The base of the stage is suggested at the first appearance datum (FAD) of Arthricocephalus chauveaui Bergeron, 1899 within the evolutionary lineage from Ar. jiangkouensis Yin in Yin & Li,1978 to Ar. chauveaui in a global scale.     

A restudy of Oryctocephalus indicus (Reed, 1910)

Restudy on morphology of Oryctocephalus indicus (Reed, 1910), based on specimens from Guizhou, China and Nevada USA, suggests that the subspecies regarded previously as Oryctocephalus indicus indicus (Reed, 1910), O. indicus latus Zhao et Yuan 2002, and O. indicus kobayashi Saito, 1934, are synonymous, and Oryctocephalus americanus Sundberg et McCollum, 2003 is a similar form of O. indicus. Oryctocephalus indicus is rediagnosed as having a glabella that is subconical in outline and tapering forward slightly; a thorax that comprises 12 segments, and a small pygidium that bears 2?3 axial rings with a terminal piece and a postaxial ridge. Oryctocephalus indicus is widely distributed in eastern Guizhou and ranges through a great interval of Kaili Formation. Its first appearance is almost identical with these events of trilobite extinction-recovery occurring at the end of the Early Cambrian, the alternation of acritach assemblages, the change of trace elements (REE) and stable isotopes (carbon) at the Wuliu-Zengjiaya section. As one of the key forms for defining the traditional Lower - Middle Cambrian boundary (the base of Cambrian Series 3 and Stage 5 in the new Cambrian chronstratigraphic standard), O. indicus has received detailed study and has more advantages than other species such as Ovatoryctocara granulata Tchernysheva, 1962 or Arthricocephalus chauveaui Bergeron, 1899.     

A restudy of Oryctocephalus indicus (Reed,1910)

Since both Chinese[1]and American Palaeontolo-gists[2]proposed separately to mark the beginning ofthe Middle Cambrian based on the first appearancedatum (FAD) ofOryctocephalus indicus[3]in thesame year ,the suggestion has been considered seri-ously and adoptedfrequently[4—18].The InternationalSubcommission on Cambrian Stratigraphy (ISCS) hasorganized the Working Group,chaired by L.B. Mc-Collum,to select candidate sections that bear poten-tial to become a GSSPfor the traditional Lowe…     

A restudy of Oryctocephalus indicus (Reed, 1910)

Restudy on morphology of Oryctocephalus indicus (Reed, 1910), based on specimens from Guizhou, China and Nevada USA, suggests that the subspecies regarded previously as Oryctocephalus indicus indicus (Reed, 1910), O. indicus latus Zhao et Yuan 2002, and O. indicus kobayashi Saito, 1934, are synonymous, and Oryctocephalus americanus Sundberg et McCollum, 2003 is a similar form of O. indicus. Oryctocephalus indicus is rediagnosed as having a glabella that is subconical in outline and tapering forward slightly; a thorax that comprises 12 segments, and a small pygidium that bears 2?3 axial rings with a terminal piece and a postaxial ridge. Oryctocephalus indicus is widely distributed in eastern Guizhou and ranges through a great interval of Kaili Formation. Its first appearance is almost identical with these events of trilobite extinction-recovery occurring at the end of the Early Cambrian, the alternation of acritach assemblages, the change of trace elements (REE) and stable isotopes (carbon) at the Wuliu-Zengjiaya section. As one of the key forms for defining the traditional Lower - Middle Cambrian boundary (the base of Cambrian Series 3 and Stage 5 in the new Cambrian chronstratigraphic standard), O. indicus has received detailed study and has more advantages than other species such as Ovatoryctocara granulata Tchernysheva, 1962 or Arthricocephalus chauveaui Bergeron, 1899.     

贵州遵义下寒武统牛蹄塘组生物群中的海绵化石

遵义松林中南村下寒武统牛蹄塘组中下部,特别是下部黑色泥岩中产有大量的海绵骨针,形态多样,初步研究有多达10属以上的海绵动物,与澄江生物群的海绵相比,牛蹄塘组的海绵动物化石其组合特征以六射海绵动物为主,它的发现增添了寒武纪生物组成的信息,为海绵动物从晚新元古代的发生以至穿越寒武纪的演化过程及寒武纪生物大爆发的定性,量度提供了重要信息及资料,描述了4属2个种。1个相似种和1个未定种。Hyalosinica sp.;Saetaspongia densa Mehl et Reitner,1993;Leptomitus teretiusculus CHen,Hou et Lu.1989;Crumillospongia cf.biporosa Righy,1986,它们分属于海绵动物的六射海绵纲和普通海绵纲。     

《王渔洋事迹征略》献疑二则

著名学者蒋寅先生《王渔洋事迹征略》一经出版,即产生了良好的学术影响。但正如陆林先生所说,该书也存在白璧微瑕。文章在陆文基础之上,也提出疑问二则,以求证于方家。     

Further support for a Cretaceous age for the feathered-dinosaur beds of Liaoning, China: New 40Ar/39Ar dating of the Yixian and Tuchengzi

We report new ⁴⁰Ar/³⁹Ar dating results obtained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast China. The first is a new sample of the Bed 6 Sihetun tuff from the Yixian Formation, previously dated by our team as middle Early Cretaceous, and recently considered by Lo et al., partially reset due to metamorphism from a nearby basaltic sill. The second is the Yixian Bed 9 tuff from Hengdaozi considered by Lo et al. to be unaffected by metamorphism and whose age, based on total fusion ⁴⁰Ar/³⁹Ar dating of biotite, argues for a Jurassic age for the Yixian Formation. The third tuff is a previously undated tuff from the upper part of the underlying Tuchengzi Formation. Single crystal total fusion ⁴⁰Ar/³⁹Ar analyses of the Sihetun sanidine showed homogeneous radiogenic Ar, Ca/K ratios, excellent reproducibility and gave a mean age of 125.0 ± 0.18 (1SD) ± 0.04 (SE) Ma. Single sanidine crystal total fusion ⁴⁰Ar/³⁹Ar analyses of the Hengdaozi tuff gave a mean age of 125.0 ± 0.19 (1SD) ± 0.04 (SE) Ma, which is indistinguishable from the Sihetun tuff. The Tuchengzi Formation tuff gave a mean age of 139.4 ± 0.19 (1SD) ± 0.05 (SE) Ma. Detailed laser incremental-heating analyses of biotite from Sihetun, Hengdaozi, and Tuchengzi tuffs show disturbed Ar release patterns and evidence of trapped argon components. We conclude from these analyses that the total fusion dates on biotite by Lo et al. are erroneously old and isotopic dating of both biotite and sanidine from tuffs of the Yixian Formation point to a middle Early Cretaceous age. The upper part of the Tuchengzi Formation can be referred to the Early Cretaceous.     

云南鲤科鱼类二新种记述

 描记采于云南东部的鲤科鱼类二新种,命名为罗平金线鱼巴Sinocyclocheilus luopingensis Li et Tao,sp.nov.和长鳍直口鲮Rectoris longifinus Li Mao et Lu,sp.nov.,前者头的背面下凹,但不呈鸭嘴形,鼻孔也开始前移到吻端,侧线鳞51,体鳞大,胸鳍长,后伸接近腹鳍起点等综合特征区别于该属所有已知种;后者各鳍较长,背鳍最长鳍条大于头长,后压达臀鳍基中部上方,胸鳍后伸达腹鳍,腹鳍后伸达臀鳍起点,臀鳍后伸达尾鳍基,体侧无一条黑色带伸达尾鳍基,可明显区别于直口鲮Rectoris posehensis Lin.     

浦东拟黑麻蝇三龄幼虫记述(双翅目:麻蝇科)

调查中在上海浦东芦苇荡里的死螃蜞体内发现三龄幼虫,经饲养羽化出浦东拟黑麻蝇Beziella pudongensis Fan,Chen et Lu,sp.n.(武夷科学,待发表)雄、雌成虫.本新种三令幼虫记述,亦是拟黑麻蝇属中的幼虫首次报道. 本新种与黑尾黑麻蝇Helicophagella melanura(Meigen)的雄虫虽貌似而不近缘,本文从它们三龄幼虫的体壁、口咽器、前气门、后气门、后突起群的突形等都有很大差异,而生态习性也显然不同,黑尾黑麻蝇幼虫常在人、畜粪中发现,是住区常见蝇种之一,而浦东拟黑麻蝇幼虫仅在大片芦苇荡地表的死螃蜞体内发现.两者绝非近缘属、种.     

Proposal and prospects for the global Lower-Middle Cambrian boundary

In recent years paleontologists have been working on the global stratotype section and standard point (GSSP) for the Lower-Middle Cambrian boundary in North America, China, Morocco, Spain and Russia. Continually, they suggest the potential first appearance datum (FAD) of the Middle Cambrian, such as Oryctocephalus indicus, Ovatoryctocara granulata, Acadoparadoxides mureroensis, Hupeolenus and Arthricocephalus chauveaui as being relevant to the potential stratotype section for the Lower-Middle Cambrian boundary. There are only a few trilobites distributed widely enough in the Early to Middle Cambrian connection, so virtually no trilobite(s) can act as the FAD for the global Middle Cambrian. The easily identified Oryctocephalus indicus is widely distributed in three realms of the global Cambrian. Its first appearance position is linked to the extinction of old species coevolution of new ones. It appears to be a comparatively good FAD of Middle Cambrian. The continuous and unbroken Wuliu section (Balang, Taijiang County, Guizhou Province, China) includes O. indicus and co-occurs with many benthic and nektonic trilobites. The evolution of acritarchs in the section, the changed characteristics of trace elements (REE and C isotopes) are generally consistent with the evolution of trilobites both above and below the boundary. Strata above the boundary yield the famous Kaili Biota. The Wuliu section is easily accessible from a main highway.     

盲走螨属四新种和二新记录种(蜱螨亚纲:植绥螨科)

在整理我们收藏的植绥螨科标本中,发现有盲走螨属四个新种和二个新记录种,记述如下。本文采用Rowell et al(1978)的毛序命名系统和Chant et al.(1994)的植绥螨科分类系统。长度测量单位为微米。模式标本保存于广东省昆虫研究所。     

雏蝗属五种蝗虫雄性外生殖器的比较(直翅目:网翅蝗科)

利用显微观察并描述了直翅目网翅蝗科雏蝗属青藏雏蝗Chorthippus qingzangensis、小翅雏蝗C．fallax、东方雏蝗C．intermedius、红胫雏蝗C．rufitibis、白纹雏蝗C．albonemus共五种雏蝗雄性外生殖器的形态特征。结果表明：五种雏蝗雄性外生殖器发生变化最为明显的部位是冠突、前突、侧板、桥和色带连片及阳茎基瓣，在种间存在明显差异。通过对雄性外生殖器的形态结构比较，在探讨蝗总科分类和系统发育上均具有重要意义，并为雏蝗属种类鉴定提供了新的分类依据。     

上海市拟黑麻蝇属一新种(双翅目:麻蝇科)

浦东拟黑麻蝇Beziella pudongensis新种系最近在上海市浦东国际机场所采获,本文作了详细描述;新种模式标本存中国科学院上海昆虫研究所.该属首次在广东深圳市发现一新种深圳拟黑麻蝇B.shenzhengensisFan(2002),本文将这两种列表作了比较.     

Further support for a Cretaceous age for the feathered-dinosaur beds of Liaoning,China:New 40Ar/39Ar dating of the Yixian and Tuchengzi Formations

We report new 40Ar/39Ar dating results obtained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast China. The first is a new sample of the Bed 6 Sihetun tuff from the Yixian Formation, previously dated by our team as middle Early Cretaceous, and recently considered by Lo et al., partially reset due to metamorphism from a nearby basaltic sill. The second is the Yixian Bed 9 tuff from Hengdaozi considered by Lo et al. to be unaffected by metamorphism and whose age, based on total fusion 40Ar/39Ar dating of biotite, argues for a Jurassic age for the Yixian Formation.The third tuff is a previously undated tuff from the upper part of the underlying Tuchengzi Formation. Single crystal total fusion 40Ar/39Ar analyses of the Sihetun sanidine showed homogeneous radiogenic Ar, Ca/K ratios, excellent reproducibility and gave a mean age of 125.0 ± 0.18 (1SD) ±0.04 (SE) Ma. Single sanidine crystal total fusion 40Ar/39Aranalyses of the Hengdaozi tuff gave a mean age of 125.0 +0.19 (1SD) ± 0.04 (SE) Ma, which is indistinguishable from the Sihetun tuff. The Tuchengzi Formation tuff gave a mean age of 139.4 ± 0.19 (1SD) ± 0.05 (SE) Ma. Detailed laser incremental-heating analyses of biotite from Sihetun, Hengdaozi, and Tuchengzi tuffs show disturbed Ar release patterns and evidence of trapped argon components. We conclude from these analyses that the total fusion dates on biotite by Lo et al. are erroneously old and isotopic dating of both biotite and sanidine from tuffs of the Yixian Formation point to a middle Early Cretaceous age. The upper part of the Tuchengzi Formation can be referred to the Early Cretaceous.``     

白粉菌一新种和一变种

报道了采至四川省南坪县九寨沟自然保护区的白粉菌两个新分类单位:九寨沟球针壳Phyllactinia Jiuzhaigouica Xie et Yin sp.nov.寄生在小蘖Berber sp.植物的叶片上,蔷薇波丝壳厚壁变种Medusosphaera rosae Golov.& Gamal var.crassiparietalis Xie et Yin寄生于红花蔷薇Rosa moyesii Hemsl.et Wils.植物的叶片上,还讨论了新种与近似种之间的区别。     

Further support for a Cretaceous age for the feathered-dinosaur beds of Liaoning,China:New 40Ar÷39Ar dating of the Yixian and Tuchengzi Formations

We report new ⁴⁰Ar÷³⁹Ar dating results obtained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast China. The first is a new sample of the Bed 6 Sihetun tuff from the Yixian Formation, previously dated by our team as middle Early Cretaceous, and recently considered by Lo et al., partially reset due to metamorphism from a nearby basaltic sill. The second is the Yixian Bed 9 tuff from Hengdaozi considered by Lo et al. to be unaffected by metamorphism and whose age, based on total fusion ⁴⁰Ar÷³⁹Ar dating of biotite, argues for a Jurassic age for the Yixian Formation. The third tuff is a previously undated tuff from the upper part of the underlying Tuchengzi Formation. Single crystal total fusion ⁴⁰Ar÷³⁹Ar analyses of the Sihetun sanidine showed homogeneous radiogenic Ar, Ca÷K ratios, excellent reproducibility and gave a mean age of 125.0±0.18 (1SD)±0.04 (SE) Ma. Single sanidine crystal total fusion ⁴⁰Ar÷³⁹Ar analyses of the Hengdaozi tuff gave a mean age of 125.0±0.19 (1SD)±0.04 (SE) Ma, which is indistinguishable from the Sihetun tuff. The Tuchengzi Formation tuff gave a mean age of 139.4±0.19 (1SD)±0.05 (SE) Ma. Detailed laser incremental-heating analyses of biotite from Sihetun, Hengdaozi, and Tuchengzi tuffs show disturbed Ar release patterns and evidence of trapped argon components. We conclude from these analyses that the total fusion dates on biotite by Lo et al. are erroneously old and isotopic dating of both biotite and sanidine from tuffs of the Yixian Formation point to a middle Early Cretaceous age. The upper part of the Tuchengzi Formation can be referred to the Early Cretaceous.     

鼠耳蝠属染色体研究进展

本文根据作者分析的安徽5种鼠耳蝠核型和文献报道的45种鼠耳蝠核型,对该属染色体组型及进化机制进行了讨论。该属染色体基本上相同,有四个共同特征,仅出现一些微小变化,我国绒鼠耳蝠是该属染色体数最多的一个种,2n=48,NF=54。通常认为,在同一个分类阶元中,染色体数目多,具有较多端部着丝粒染色体的为较原始类型,反之则为较进化类型。因此,绒鼠耳蝠可能是现存鼠耳蝠属动物最原始的种,该属的演化将主要遵循罗伯逊易位和衔接易位。在进化中是否伴随小染色体丢失,尚需进一步研究。     

中国西南洞穴球体蛛一新属——喀蛛属(蜘蛛目,球体蛛科)(英文)

本文报道采自中国西南的球体蛛科1新属——喀蛛属Karstia gen.nov.,包括1新种和1新组合:上扬子喀蛛,新种Karstia upperyangtzica sp.nov.,模式标本采自中国贵州省的喀斯特洞穴中;科氏喀蛛,新组合Karstia coddingtoni(Zhuet al.2001)comb.nov.,标本采自中国贵州省和广西壮族自治区的喀斯特洞穴中。基于雌、雄蛛特有的形态学特征而建立本新属,详细描述了新种和重新描述了新组合种,对该属的生物地理进行了简要讨论。     

Nuclear transfer using nonquiescent adult fibroblasts from a bovine ear

The natural reproduction of mammal is sexual reproduction, which needs fertilization involving sperm and oocyte. Nuclear transfer provided an asexual reproduction method for mammal. Donor cells used in previous experiments of nuclear transfer were mostly from undifferentiated or non-terminally differentiated cells, such as embryonic or fetal cells. However, since Wilmutet al. obtained a viable lamb by transfer of an adult sheep somatic cell into an enucleated oocyte, nuclear transfer using adult somatic cell has been successful in several species. Wilmutet al. suggested that it was a key factor for the success of somatic nuclear transfer to induce the donor cells into GO phase (“GO-phase hypothesis”). In order to verify the Gophase hypothesis, nonquiescent adult fibroblasts from a bovine ear were transferred into enucleated bovine oocytes. The experiments showed that the rate of electrofusion after micromanipulation was above 50%, the cleaving rate was 54.5% and 9.1% of those reconstructed embryos developed to 32-cell stage. These results indicate that for cattle, nuclei from nonquiescent adult somatic cells introduced into enucleated oocytes are at least capable of supporting early development.