中国肯氏兽-山西鳄组合带的新发现之二:山西二马营组幻阔齿兽(兽孔类:兽头类)一新种(英文)

记述了2012年在山西柳林三交二马营组上部采集的一个兽头类下颌标本,将其命名为幻阔齿兽三交种(Nothogomphodon sanjiaoensis sp.nov.)。新种以下列特征区别于属型种N.danilovi:齿骨下缘起伏,犬齿基部卵圆形,犬齿与第一犬后齿间有显著间隙,犬后齿后缘无辅助齿尖。幻阔齿兽以其特殊的犬后齿形态与具裂齿的基干犬齿兽相似,它也是已知的唯一一类具有这种复杂裂齿齿系的兽头类。将俄罗斯的引鳄动物群与中国的肯氏兽-山西鳄组合带进行比较发现,幻阔齿兽是二者唯一共有的属,而中国的二马营组与克拉玛依组却没有共享的属。     

新疆东北部晚侏罗世一新的柱齿兽

描述了哺乳纲柱齿兽目柱齿兽科(Docodontidae,Docodonta,Mammalia)一新属种——孙氏尖钝齿兽(Acuodulodon sunae gen.et sp.nov.)。标本产于新疆东北部准噶尔盆地五彩湾地区上侏罗统牛津阶石树沟组上部(159～161 Ma),为一不完整左下颌骨及齿列。新属下臼齿具柱齿兽类典型特征:齿尖b位于齿尖a前方;齿尖c位于齿尖a后舌侧;齿尖a前舌侧发育有齿尖g。不同于其他柱齿兽,新属下臼齿无齿尖e和齿脊b-e。齿尖g和齿脊b-g很快被磨蚀掉而齿尖a和c却能保持尖锐状态,表明该动物的臼齿在生活中具备并保持切割和碾压双重功能。基于下臼齿性状特征的系统发育分析表明,柱齿兽目作为一单系类群具有显著的鉴定特征。其中尖钝齿兽和Itatodon+(Simpsonodon,Castorocauda+(Tegotherium+Sibirotherium))形成一单系子类群;但tegotheriids各分子未形成独立于柱齿兽科的单系类群。尖钝齿兽的下颌齿骨亦为典型的柱齿兽类型。齿骨内侧下部近腹缘有浅的齿后骨槽和宽大的内侧脊,但两者未延伸到下颌关节髁的基柄部。这表明尖钝齿兽的齿后骨与齿骨的连接比摩根齿兽类更为松散,其中耳在进化上更接近真正意义上的哺乳动物中耳。     

垣曲盆地一新的细齿兽(食肉目,细齿兽科)化石

记述了在山西省垣曲县毫清河右岸火石坡发现的细齿兽一新种──毫清河细齿兽？（Ｍｉａｃｉｓ？ ｂｏｑｉｎｇｈｅｎｓｉｓ　ｓｐ　 ｎｏｖ．）。新种与细齿兽属所有已知种不同在于上臼齿具发育的前、后小尖,且小尖均具明显的前、后棱。     

山西垣曲盆地中始新世的原翼齿兽(鬣齿兽科,肉齿目,哺乳纲)化石

记述了在山西省垣曲县王茅乡郭家村火石坡地点发现的原翼齿兽属一新种──童氏原翼齿兽(Ｄｒｏｐｔｅｒｏｄｏｎ ｔｏｎｇｉ ｓｐ．ｎｏｖ．)。新种比伊尔丁原翼齿兽(Ｐ．ｉｒｄｉｎｅｎｓｉｓ)个体小、下颌联合部靠前、下前臼齿之间有齿隙、ｍ３跟座小。新材料为垣曲盆地可能存在中始新世伊尔丁曼哈期地层提供了证据。     

张和兽的齿列和前肢形态

张和盖是目前唯一保存完整完整骨架的对齿兽类。其齿列特征表明它属于兽科,该科为原始兽学中主要繁衍于北方大陆中生代后期一个咀嚼方式以上下臼齿对咬为主的单系类群。张和兽骨骼形态显示其前肢姿势处于外展趴卧与内收直立之间,兼有树上和地面活动的能力,是原始兽类中趋于以地面活动为主的成员。附录列举了哺乳类的主要齿列和骨骼性状序理信分布矩阵。     

张和兽(Zhangheotherium)的齿列和前肢形态

张和兽（Zhangheotherium）是目前唯一保存完整骨架的对齿兽类。其西列特征表明它属于兽科（Spalacotheriidae）,该科为原始兽类中主要繁衍于北方大陆中生代后期一个咀嚼方式以上下日齿对咬为主的单系类群。张和兽骨骼形态显示其前肢姿势处于外展趴卧（sprawling）与内收直立（parasagittal）之间,兼有树上和地面活动的能力,是原始兽类中趋于以地面活动为主的成员。附录列举了哺乳类的主要齿列和骨骼性状序列及分布矩阵。     

中国尖齿兽牙齿替换方式及其对哺乳动物进化的意义

中国云南下禄丰组的早侏罗世中国尖齿兽的新材料显示出从前未曾认识到的早期哺乳动物牙齿特征．中国尖齿兽的门齿和犬齿,像非哺乳类犬齿兽一样,是多次替换的。新的中国尖齿兽幼体标本保存有前臼齿,前臼齿替换一次之后,在较大（更老）的标本上就永久消失。犬后齿分化为前臼齿与臼齿,以及前臼齿仅替换一次是现代哺乳动物的衍生特征。中国尖齿兽前边的臼齿可能无后继齿替换而消失;后边的臼齿替换一次．中国尖齿鲁当其成体的牙齿还在经受替换期间,头骨仍在继续生长。中国尖齿首是所有其他哺乳动物的姊妹类群。中国尖齿兽的牙齿替换方式可解释为从爬行类原始多出齿系向哺乳动物进步的二出齿系进化的中间过渡类型。由中国尖齿兽的多出齿系和其头骨无期限式生长推知,该类动物尚不具备现代哺乳动物所具有的有期限生长方式和哺乳特征。     

钝脚目全棱齿兽科的分类

本文在重新观察某些亚洲土著钝脚类的基础上,结合前人研究成果,将原全棱齿兽科、古脊齿兽科和牧兽科合并成一个科──全棱齿兽科,分全棱齿兽和牧兽两个亚科,并对其组成做了分析。     

江西池江盆地阶齿兽一新种

<正>1962年在我国广东南雄盆地首次发现了阶齿兽类化石(周明镇等,1973;郑家坚等, 1973),随后在安徽潜山、湖南茶陵、陕西石门、江西大余等地的中古新世地层中相继发现该类动物的化石材料,尤其是在广东南雄、江西大余和湖南茶陵三个地点,有大量的阶齿兽类化石产出。阶齿兽类在中古新世时在亚洲南部是广泛分布的。本文记述的阶齿兽材料是2003年在江西池江盆地发掘到的,此标本与已知的阶齿兽属中各种均有明显差别, 故建立一新种——丁氏阶齿兽(Bemalambda dingae sp.nov.)。     

双尖齿兽科(Didymoconidae)一新种及有关地点地层问题

本文记述了内蒙古二连盆地“马捷茨营地”(Camp Margetts)地区中始新世阿山头组产出的一种古双尖齿兽:Archaeoryctes borealis sp. nov.。该种为中国北方及中亚一带已知双尖齿兽科中形态最为原始、出现时代最早的分子。它使中国南方早期的双尖齿兽科成员与北方较晚期的成员建立了某种关系。文中对与该种产出地点及地层有关的问题进行了讨论。     

Postcanine microstructure in Cricodon metabolus,a Middle Triassic gomphodont cynodont from south‐eastern Africa

Cricodon metabolus is a trirachodontid cynodont from the Anisian (Middle Triassic) of eastern and southern Africa. It has labiolingually expanded (gomphodont) postcanines but also a sectorial tooth in the last postcanine locus. In this paper, we examine the crown microstructure of isolated sectorial and gomphodont postcanines belonging to the holotype specimen of this taxon using scanning electron microscopy. The enamel of both teeth is prismless and composed of discontinuous columnar divergence units, supporting the consistent presence of synapsid columnar enamel in cynognathians. Abundant tubules and numerous irregularly spaced incremental lines are also visible in the enamel and dentine layers in each tooth. This study reveals that the enamel thickness varies along the tooth row in Cricodon as the enamel layer of the gomphodont postcanines is 11.5 times thicker than that of the sectorial crown. It is likely that this difference reflects occlusal stresses and fewer replacements in gomphodont postcanines relative to sectorial teeth. Approximately 100 incremental growth lines of von Ebner are present in the dentine layer, indicating that the deposition of the dentine by odontoblasts occurred for three months before the animal's death.     

RECENT VERSUS RELIC: DISCERNING THE GENETIC SIGNATURE OF FUCUS VESICULOSUS (HETEROKONTOPHYTA; PHAEOPHYCEAE) IN THE NORTHWESTERN ATLANTIC1

Fucus vesiculosus L. is one of the most widespread macrophytes in the northwestern Atlantic, ranging from North Carolina (USA) to Greenland (DK). We investigated genetic diversity, population differentiation, patterns of isolation by distance, and putative glacial refugial populations across seven locations from North Carolina (USA) to Cape Breton Island, Nova Scotia (Canada), with microsatellite analyses. Distinct northern versus southern (Delaware–North Carolina) populations were revealed by microsatellite data. Five of six microsatellite loci were fixed in populations in North Carolina, suggesting a recent founder event or a bottleneck, and the same homozygous genotype was found in herbarium materials collected on the North Carolina coast from more than 60 years ago. An additional set of individuals from the northern limit in Greenland was included in our analysis of mitochondrial intergenic spacer (mt IGS) haplotypes in the northwestern Atlantic. Remarkably, 184 of 188 F. vesiculosus specimens from North Carolina to Greenland shared the same haplotype. Recent colonization of the North American shore from Europe is hypothesized based upon the ubiquity of this common haplotype, which was earlier reported from Europe.     

Description of two new species of Clivina Latreille (Coleoptera, Carabidae, Clivinini) from southeastern United States

Two new species of the genus Clivina Latreille are described. One, Clivina choatei Bousquet & Skelley, belongs to the nominotypical subgenus and is known from six specimens collected in northern Florida. The species is structurally similar to Clivina myops Bousquet, known only from the holotype found in North Carolina, but differs among others by its smaller size and wider elytral striae. The second species, Clivina alabama Bousquet, belongs to the subgenus Antroforceps Barr and is known from two specimens collected in north-central Alabama. The species is structurally most similar to Clivina sasajii Ball, known only from Latimer County in Oklahoma, but differs among others in the absence of eyes and in having the pronotum and elytra proportionally wider.     

Variation among Populations of Belonolaimus longicaudatus

Three North Carolina populations of Belonolairnus longicaudatus differed significantly from three Georgia populations in stylet measurements, the c ratio, the distance of the excretory pore from the anterior end for both sexes; the a ratio for females only; and the total body length, tail length, and spicule length for males only. The Georgia nematodes were stouter, and the females possessed sclerotized vaginal pieces. The distal portion of the spicules of North Carolina males had an indentation and hump lacking in those of the Georgia males. The haploid number of chromosomes was eight for males from all populations of B. longicaudatus and a North Carolina population of B. maritimus. Interpopulation matings of the Tarboro, N.C. and Tifton, Ga. populations indicated that the offspring produced were infertile. Morphological differences and reproductive isolation suggest that the North Carolina and the Georgia populations belong to different species.     

Serological Strains of Tobacco Ringspot Virus Transmitted by Xiphinema americanum

Five serological strains of tobacco ringspot virus isolated from naturally infected tobacco in North Carolina, and a strain isolated from watermelon in the Rio Grande Valley of Texas were transmitted from cucumber to cucumber by mass-screened and handpicked Xiphinerna americanum from North Carolina. The Eucharis mottle strain from Peru was not transmitted, indicating that a specific strain-vector relationship may exist between the geographically isolated strains from North and South America.     

Effects of Soil Type on the Damage Potential of Meloidogyne incognita on Soybean

Effects of soil type on the reproduction and damage potential of Meloidogyne incognita on soybean, Glycine max (L.) Merr., were determined at five locations in North Carolina, including one site where plots with six soil types were established. M. incognita reproduced readily on a susceptible soybean cultivar in most soil types, with somewhat limited reproduction in muck soils. The relationship between initial population densities and yield varied among soil types and nematode populations. Yield losses were greatest in sandy and muck soil types, with less nematode damage occurring in the clay soil types. A North Carolina and a Georgia population of M. incognita differed greatly in their ability to reproduce on soybean and suppress growth. The North Carolina population had a moderate effect on yield in 1981 and only a slight effect in 1982. In contrast, a Georgia population severely limited soybean growth and yield at lower initial population densities in 1983, Initial population densities of the nematodes and physical and chemical edaphic factors accounted for much of the variation of soybean yield and nematode reproduction.     

MORPHOLOGICAL AND GENETIC VARIABILITY IN PLANTAGO CORDATA (PLANTAGINACEAE), A THREATENED AQUATIC PLANT

Morphological and genetic variation were studied in Plantago cordata Lam., an imperiled aquatic plant. The existence of distinct seasonal morphs was confirmed by numerical morphological analyses of specimens from 53 populations. Plants from two North Carolina populations possessed leaves that were significantly shorter, narrower, and fewer-veined than populations in other portions of the species range. Genetic variation within and among ten populations in seven states/provinces (Illinois, Missouri, New York, North Carolina, Ohio, Ontario, and Wisconsin) was examined electrophoretically. The species is an apparent allopolyploid with fixed heterozygosity observed at 67% of the loci surveyed. Electrophoretic variation was mostly partitioned among populations. The genetic identity among populations was high except for North Carolina populations which differed at 27% of the loci surveyed.     

GENETIC VARIATION IN PLANT-INSECT ASSOCIATIONS: SURVIVAL OF LEPTINOTARSA DECEMLINEATA POPULATIONS ON SOLANUM CAROLINENSE

Populations of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), from the east coast of the United States differ in their ability to survive on a wild host, Solanum carolinense (Solanaceae), but not on their most important cultivated host, Solanum tuberosum. On the wild host, the North Carolina population survived best, while populations from Virginia, New Jersey, and Connecticut exhibited uniformly low survival. Formal genetic studies of populations from Connecticut and North Carolina demonstrated heritable variation in the ability to survive on S. carolinense both between and within populations; the North Carolina population had the higher heritability for this trait. Overall, there was no genetic variation between populations or within the North Carolina population for survival on S. tuberosum, but such variation existed within the Connecticut population. Hybrids and backcrosses between these two lines all survived at intermediate levels, although survivorship did not appear to be inherited additively. Differences in survival were greater than differences in adult weight at emergence and development time of the survivors. Leptinotarsa decemlineata was first reported from North Carolina less than 100 years ago. The rapid expansion of L. decemlineata's host range in North Carolina is attributed to the poor synchrony between the insect and S. tuberosum compared to more northerly locations. In contrast to the prediction of a strong negative correlation in fitness on different host species, the ability of L. decemlineata to survive on S. carolinense was not correlated with that on S. tuberosum. Adult weight and female development time were significantly positively correlated across hosts. Our results are in accord with most previous studies in which strong negative correlations in fitness of specialized phytophagous insects feeding on different hosts were expected, sought, but not found.