长尾黄鼠年龄鉴定及其种群年龄组成的研究

本文报道以牙齿生长发育及臼齿磨损度鉴定长尾黄鼠年龄的方法,探讨了长尾黄鼠年龄与体重、体长及繁殖力的相互关系。将824只黄鼠划分为5个年龄组。分析表明,除幼体组外,其他各组的体重、体长及繁殖力和产仔数均与年龄无关。     

珠江三角洲黄毛鼠种群年龄鉴定及年龄组成的研究

本文以眼球晶体干重,牙齿磨损度和牙齿切片观察白垩质沉积环的方法,鉴定黄毛鼠的年龄。探讨了晶体干重与年龄组之间的线性关系,将3337只黄毛鼠划分为5个年龄组,同时分析了不同月份的种群年龄组成,可以反映种群动态和繁殖特征的趋势。通过实验证明了牙齿切片观察臼齿白垩质沉积环,用来鉴别年龄,对寿命短的动物,特别对于啮齿动物可行性不大。     

灰旱獭生命表和繁殖的初步研究

1985年4-9月,于野外捕捉灰旱獭(Marmota baibacina)911只,经鉴定划分为12个年龄组,用生命表法探讨该种群数量动态。灰旱獭的期望寿命(e_x)雌雄分别为3.4393、2.8798年,平均死亡率(q)雌雄分别为0.2956、0.2538。繁殖力以第5-8年龄组较强。妊娠期35-40天。哺乳期约30天。平均产仔数6.027只。内禀增长率(r_m)为0.1695/年。周限增长率(λ)为1.1847/年。世代时间(T)为7.1436/年。种群经一世代的净增殖率(R₀)为3.3574。     

喜马拉雅旱獭的洞型观察

旱獭与医学关系密切,又有很高的经济价值。过去国内外对蒙古旱獭(Marmota sibirica)、灰旱獭(M. baibacina)、草原旱獭(M. bobac)和长尾旱獭(M. caudata)等的洞型都有报道。本文系作者1960-1975年在甘肃省洮江县和青海省共和县,剖析观察了喜马拉雅旱獭(M. himalayana)150余个洞型结构资料,现简报如下。     

灰旱獭(Marmota baibacina)移动性的模拟实验

灰旱獭(Marmota baibacina)是珍贵的毛皮动物,也是我国天山山地鼠疫自然疫源地的主要储存宿主。研究该动物的生态学,对于阐明自然疫源地的动物流行病规律及指导制订消灭疫源性的措施具有重要的意义。 用标记动物进行动物生态学研究,国外于五十年代即已作了大量工作(PendletonR.C.1956)。一些苏联学者为解决鼠疫动物流行病的一些理论问题,进行了许多旱獭生态学研究。例如,Bn6n~os(1961,1962)用染色标记方法对灰旱獭的移动性进行了观察,把旱獭移动分为迁出式移动和种群内移动,Kn3nJios(1964)用染色标记法对红旱獭(Marmota caudata)的活动性和移动性进行了详细的观察;bepcuⅡgena(1966)用放射性同位素及染色标记法对灰旱獭的种群内接触进行了试验研究。     

高原低氧适应动物新疆灰旱獭右心室重构的组织学改变

目的探讨新疆灰旱獭高原低氧适应性改变致右心室重构组织学改变。方法应用免疫组化技术检测新疆灰旱獭右心室缝隙连接蛋白43(CX43)蛋白表达,同时应用HE染色和Masson染色观察心室肌结构和纤维化程度变化。结果心肌细胞肥大,胶原纤维增多,右心室肥厚指数、体重指数明显增高。CX43蛋白表达减少和(或)分布的改变。结论高原低氧致新疆灰旱獭右心室结构重构,可作为研究高原低氧适应性机制的理想动物模型。     

蒙古旱獭体重体长变化及其年龄划分的研究

本文报告了645只蒙古旱獭体重体长变化与年龄的关系。结果表明:体重体长随年龄增长而递增,但体重和体长的增长速度和幅度不同。体重增长速度较快,幅度较大;体长增长速度较慢,幅度较小。经相关分析证明:体重体长与年龄呈正相关,相关系数和回归方程为: Y_w=1377.16x~(O.7729),R_w=0.9970; Y_L=33.95x~(0.2529),R_L=0.9947。 并根据相邻两个年龄组间体重均数有显著性差异(P<0.01),频数分布重叠不明显;组内变异具有一致性等特征,参考各年龄组蒙古早獭体重标准值(Mean ±Sx),划分了各年龄组早獭的体重范围。     

大沙鼠的年龄鉴定与种群年龄组成

在鼠类生态学的研究中 ,对鼠类年龄的鉴定是一项重要的工作。年龄组成是种群的重要特征之一 ,它有助于了解种群的年龄结构以及种群数量变动的规律。大沙鼠 (Ｒｈｏｍｂｏｍｙｓｏｐｉｍｕｓ)是中亚地区荒漠及半荒漠草原的重要害鼠之一 ,在内蒙古西部的梭梭 (Ｈａｌｏｘｙｌｏｎａｍｍｏｄｅｎｄｒｏｎ)林区 ,由于大沙鼠的啃咬 ,影响了该地区梭梭林的正常结实 ,从而降低了结实量[1 ] 。同时 ,大沙鼠又是鼠疫和皮肤利什曼病的重要宿主。对大沙鼠的年龄鉴定与种群年龄组成进行研究 ,将有助于了解其种群数量变动的规律 ,从而为有效防治大沙鼠鼠…     

野生大熊猫的年龄鉴定

本文根据大熊猫门齿齿骨质年轮线数目鉴定了大熊猫的实际年龄,并按其头骨各骨缝的生长愈合情况及臼齿磨损程度将大熊猫划分为6个年龄组。     

基于骨龄学方法鉴定吐鲁番沙虎的年龄

基于113个标本的吻肛长频次数据,初步划分吐鲁番沙虎(Teratoscincus roborowskii)的年龄组,各年龄组共选取54例个体,分别截取第2右前趾骨第3趾节,用常规石蜡切片法进行了骨龄学鉴定。同时,根据野外标记重捕方法获得个体的形态学生长指标来验证年龄组划分的合理性。结果表明,吐鲁番沙虎雌雄个体间吻肛长差异不显著,可以合并进行年龄鉴定;吐鲁番沙虎的吻肛长和骨龄间有显著的相关性;对于小于6龄的个体,骨龄学的方法适用于吐鲁番沙虎年龄的鉴定。     

Enamel thickness of deciduous and permanent molars in modern Homo sapiens

This study presents data on the enamel thickness of deciduous (dm2) and permanent (M1-M3) molars for a geographically diverse sample of modern humans. Measurements were recorded from sections through the mesial cusps of unworn teeth. Enamel is significantly thinner on deciduous than on permanent molars, and there is a distinct trend for enamel to increase in relative thickness from M1 to M3. The relatively thicker enamel of M2s and especially M3s can be related to the overall reduction in size of more distal molar crowns, which has been attained through a differential loss of the dentine component. Enamel tends to be thicker on the protocone than on the paracone, and thicker on the protoconid than on the metaconid, but its distribution is not wholly concordant with models that predict increased thickness as a means by which to counter heavier attritional loss on these "functional" cusps. Indeed, the thickness of enamel tends to be more variable on cusp tips and occlusal surfaces than over the lateral aspects of cusps. The proportionately thicker enamel over the lateral aspects of the protocone and protoconid more likely serves as a means to prolong functional crown life by preventing cusp fracture, rather than being an adaptation to increase the attritional longevity of wear facets. The present data suggest that the human dentition is not predisposed to develop a helicoidal wear plane through the disposition of molar enamel thickness.     

Enamel thickness and the helicoidal occlusal plane

In the present study 38 unworn maxillary molars (M¹ = 16, M²= 12, M³ = 10) of modern humans from a Slavic necropolis were sectioned through the mesial cusps in a plane perpendicular to the cervical margin of the crown. Five slightly worn M¹s and one slightly worn M³ were also used thus increasing the total sample to 44, but measurements made on the worn areas were coded as missing values. Seven measurements of enamel thickness as well as the heights of the protocone and the paracone dentine horns were recorded in order to analyze whether changes in these dimensions in anteroposterior direction can be related to the helicoidal occlusal plane. Uni- and multivariate analyses revealed that the distribution of enamel thickness within and between maxillary molars corresponds to a helicoidal occlusal wear pattern. Enamel thickness along the occlusal basin increases from anterior to posterior, which may lead to rapid development of a reverse curve of Monson in first molars when compared to posterior teeth. However, although these overall differences together with the serial, especially delayed eruption pattern of human molars, contribute to the marked expression of the helicoidal occlusal plane in Homo, differences in enamel patterning between molars indicate that a helicoidal plane is a structural feature of the orofacial skeleton. In contrast to first upper molars, second and third molars show absolutely and relatively thicker enamel under the Phase I wear facet of the paracone, i. e., the lingual slope of the paracone, than under the Phase II facet of the protocone, i. e., the buccal slope of that cusp. These proportional differences are most pronounced in M³, as evidenced by uni- and multivariate statistics. It thus appears that the pattern of enamel thickness distribution from M¹ to M³ follows a trend towards providing additional tooth material in areas that are under greater functional demands, that is, corresponding to a lingual slope of wear anteriorly and to a flat or even buccal one posteriorly. In addition, the heights of the dentine horns in anteroposterior direction change in a way that lends support to the hypothesis that the axial inclination of teeth could be one of the most important factors for the development of the helicoidal occlusal plane. Finally, the changes in morphology and enamel thickness distribution from first to third upper molars found in this study suggest that molars could be “specialized” in their function, i. e., from performing proportionally more shearing anteriorly to increased crushing and grinding activities posteriorly. © 1994 Wiley-Liss, Inc.     

山东临朐中新世松鼠类一新属

本文描述的Meinia asiatica gen.et sp.nov.代表我国新第三纪首次发现的一类飞松鼠,化石采自山东省临朐县解家河中中新统山旺组,新属的特征表明,它与欧洲新第三纪的Sciu(?)optera类有接近的亲缘关系。     

内蒙古乌兰塔塔尔地区中渐新世的圆柱齿鼠科啮齿类

本文记述了发现在乌兰塔塔尔地区的中渐新世圆柱齿鼠科化石。根据牙齿特征,将乌兰塔塔尔动物群中原先的阿尔丁鼠(Ardynomys)和圆柱鼠(Cyclomylus)分别放到异鼠(Anomoemys)和察干鼠(Tsaganomys)属中,将原“小圆柱鼠”(Cyclomylus minutus Kowalski,1974)改订为小察干鼠(Tsaganomys minutus)。在记述洛异鼠(Anomoernys lohiculus)、阿尔泰察干鼠(Tsaganomys altaicus)和小察干鼠的同时,讨论了它们的种内变异。此外还对察干鼠和圆柱鼠的齿冠和齿根关系问题做了初步探讨。     

山西垣曲先炭兽类一新种

本文主要报道1983年9月,在山西省垣曲县寨里发现的一件较完整的先炭兽类老年个体上颌骨.带有颇为完整的左、右齿列. I~1-P~2 各齿前、后均有较长的齿隙. P~1、P~2、P~3 前的齿隙颌骨上,保留有乳前臼齿的齿槽.这块标本在大小及形态特征上,与目前所知先炭兽属 Anthracokeryx 中任何种都有相当大的差异.它代表了该属中的一个新种.     

江苏泗洪下草湾中中新世脊椎动物群——5.松鼠科(哺乳纲,啮齿目)

江苏泗洪下草湾组系我国现知中中新统中发现松鼠化石种类最多,材料最丰富的一个层位.采自松林庄、双沟和郑集的91件标本,代表了五个属、种松鼠,其中有飞松鼠二种, Parapetaurista tenurugosa 和 Shuanggouia lui, 花栗鼠一种, Eutamias sihongentis, 树松鼠一种, Plesiosciurus sinensis,以及一种很可能为地松鼠的松鼠未定属、种, Sciuridae gen. et sp. indet..本文对上述松鼠进行了描述和对比,初步讨论了它们与欧洲和北美一些松鼠的关系,并根据松鼠组合的性质,对该动物群的时代作了估计.     

云南曲靖晚始新世的梳趾鼠类化石(英文)

根据新材料修订了Ｄｉａｎｏｍｙｓ属及其两个种（Ｄ． ｏｂｓｃｕｒａｔｕｓ和Ｄ． ｑｕｊｉｎｇｅｎｓｉｓ）的鉴定特 征。原定为Ｄ、ｏｂｓｃｕｒａｔｕｓ的Ｐ４应为ｄＰ４,原定的Ｍ１／２和ｍ１／２分别被确认为Ｍ１和ｍ２,原属 Ｄ．ｏｂｓｃｕｒａｔｕｓ的ｐ４,实属Ｄ．ｑｕｊｉｎｇｅｎｓｉｓ。Ｄ．ｑｕｊｉｎｇｅｎｓｉｓ与Ｄ．ｏｂｓｃｕｒａｔｕｓ的区别除个体较大 外,还在于其上颊齿具分叉的后脊,ｍ１具下中脊和ｐ４具较发育的附加刺。另建立了一新属 （杨氏鼠Ｙｏｕｎｇｏｍｙｓ）,包括二新种（云南杨氏鼠Ｙ ．ｙｕｎｎａｎｅｎｓｉｓ、小杨氏鼠Ｙ ｐｉｓｉｎｎｕｓ）和一未 定种（Ｙｏｕｎｇｏｍｙｓ？ｓｐ．）。ｙｏｕｎｇｏｍｙｓ的主要特征为：颊齿比例上较窄长,齿冠较低,主尖钝,脊 较细而低;上臼齿长大于宽,后脊向原尖斜伸,内脊较低;下臼齿下原尖后臂较向后伸,无明显 的舌部,下内尖臂很弱,横向,不与下外脊连等。 Ｙ ｐｉｓｉｎｎｕＳ与 Ｙ ｙｕｎｎａｎｅｎｓｉｓ的区别在于个体 较小,齿冠较低,脊更细弱,较显丘形,上臼齿次尖位置向舌侧移,具较明显的后小尖,和后脊 不与原尖连等。 用ＰＡＵＰ ３．１．１对亚洲古近纪的梳齿鼠类进行了系统分析,表明第四前臼齿的     

Tooth wear in eastern grey kangaroos (Macropus giganteus) and western grey kangaroos (Macropus fuliginosus), and its potential influence on diet selection, digestion and population parameters

As teeth wear in eastern and western grey kangaroos, the pattern of enamel ridges changes. This affects the amount of available cutting edges and consequently the masticatory efficiency. These kangaroos also have molar progression. There is evidence for the independence of rates of tooth wear and molar progression, and variation is found in the maximum amount of wear attained by teeth both within and between populations. This variation has the potential to affect diet selection, digestion and population parameters.     

记云南禄丰发现的Lophochoerus一新种

本文对1981年冬在云南省禄丰古猿化石地点发现的脊齿猪(Lophochoerus)进行了描述和对比。禄丰脊齿猪与仅发现于西瓦立克的同属几种之间在前臼齿和臼齿上有一定的区别,为此,另建立一新种Lophochoerus lufengensis sp,nov., 代表我国晚中新世地层该类化石的首次发现。     

Experimental fluoride accumulation and toxicity in the short-tailed field vole (Micvotus agrestis)

Vegetation established naturally on three industrial sites contaminated by either airborne or soilborne fluorides was used to formulate dietary feed for a laboratory-reared population of field voles ( Microtus ugrestis L.), an herbivorous species indigenous to all three locations. Animals exposed to laboratory diets containing 100–300 mg F kg^-1 derived from vegetation from around the aluminium smelter and fluorochemical works showed reduced live weight gain, between 40 and 100% mortality and developed marked dental lesions. These comprised banding of the enamel, loss of colour and erosion of the cutting surfaces of the incisors, and dentine cavitation and erosion of the grinding faces of the molar teeth. These morphological changes were accompanied by excessive accumulation of fluoride in the teeth. Voles consuming a diet of vegetation from the mine tailings site with a similar level of fluoride (100 mg kg^-1) as for the other industrial locations, showed only slight dental changes and no weight loss or early mortality. This pattern for laboratory-bred voles is similar to that experienced in populations of this species in the wild, and the contrast in the severity of the dental lesions is ascribed to intersite differences in the chemical speciation and bioavailability of fluoride.