禄丰古猿的“小兄弟”

<正>共同发现于禄丰古猿遗址的伴生动物中,有两个禄丰古猿的"小兄弟"——池猿和中国兔猴,在分类学上,它们同归于灵长目,但一经复原后,它们的相貌却迥然不同,大小各异。池猿大小和现生的黑长臂猿接近,而中国兔猴的形体像小猫或大老鼠一样,若不是依它的生物学特性归于灵长目,真的很难相信它也是小猴子。逛动物园时,面对活蹦乱跳的猴子、像荡秋千似的长臂猿,还有体型更大的猩猩、黑猩猩、大猩猩,人们都会停步好奇地多看两眼,因为它     

山猿之谜：直立行走的山猿是人类的祖先吗？（下）

根据最新科研成果复原的山猿头像。作者帕维尔·梅杰（捷克）山猿之谜：直立行走的山猿是人类的祖先吗？（下）吴文裕新的突破１９９１年,西班牙巴塞罗那（Ｂａｒｃｅｌｏｎａ）的萨巴德尔（Ｓａｂａｄｅｌ）古生物研究所的一对古生物学家夫妇迈克·克勒（ＭｅｉｋｅＫｈ...     

禄丰古猿的复原

当你步入博物馆大厅,参观璀灿的中华民族古代文化时,都会被那尊尊栩栩如生的不同时代的远古人类塑像所吸引。正是因为这些,才使我们一睹几百万或几十万年前人类祖先的尊容,从中探知人类体质的进化历史。然而,这些复原像又是怎样制作的呢?让我扼要地将禄丰古猿的复原过程加以介绍。禄丰古猿化石发现于我国云南省禄丰县,这是生活在距今800万年前的、向南方古猿和非洲大猿方向进化的一种猿类。丰富的头骨和下颌骨化石提供了可靠的复原依据。有关学者对这些化石进行过十余年的     

华南化石猩猩前部牙齿釉面横纹与牙冠形成时间研究

釉面横纹的分布与数目可以反映牙齿生长发育的时间和速率变化, 在化石研究中能为复原个体生活史提供重要依据。本研究运用扫描电子显微镜观察华南化石猩猩门齿、犬齿釉面横纹分布与数目, 并估算门齿和犬齿牙冠形成时间, 结果如下: 牙冠从牙尖至牙颈方向釉面横纹分布密度有疏密变化, 牙尖釉面横纹密度小于10条/mm, 中间至牙颈釉面横纹密度较尖部增大, 大约10-15条/mm; 犬齿釉面横纹数目多于门齿, 雄性犬齿釉面横纹数目多于雌性; 根据釉面横纹计数及其生长周期的组织切片观察结果, 估算门齿牙冠形成时间大约为2.97-6.66年, 犬齿雄性长于雌性, 分别为6.25-11.31年和4.28-7.29年。与一些古猿、早期人类、现代人以及现生大猿比较, 华南化石猩猩釉面横纹整体密度稍大于南方古猿和傍人, 小于黑猩猩、大猩猩、现代人和禄丰古猿; 除侧门齿外, 华南化石猩猩釉面横纹数目明显多于南方古猿、傍人和现代人, 与大猩猩接近; 华南猩猩前部牙齿牙冠形成时间与现生大猿、禄丰古猿差别不大, 与现生猩猩最相近, 长于南方古猿和傍人。     

古灵长类是行动迟缓的生物

在肯尼亚的拉森格岛,不久前发掘出一批一千八百万年前的原康修尔猿非洲种的头盖骨碎片。这使古生物学家们第一次准确地复原了这种灵长类的标本。肯尼亚国立博物馆的马丁·皮克福德在拉森格工地发现的大量海龟鳞甲(外部的角质板)中,混有两块很大的头盖骨背部碎片。虽然经过拼接以后,略显得有些变形,但差不多已是个完整的标本了。沃克和他的同事们推算了原康修尔猿非洲种的体重,大约是11公斤。接近于成年雄性疣猴的体重。它的脑容量约167.3毫升,研究人员认为这个数字比现生的任何一种猴子的相对脑重都要大一     

宁夏同心发现的一颗上猿牙齿

本文记述了采自宁夏同心地区中中新世(相当于通古尔早期)地层中一颗上猿的左下第二臼齿。它的齿冠形态和Hurzeler(1954)以Goriach地点为基础所总结出的上猿下臼齿的“模式”形态基本一致,而和其它几个在形态上比较接近的属,如湖猿、树猿、宽齿猿和池猿等有较明显的区别。这是我国第一颗比较可靠的上猿牙齿化石。     

云南元谋小河地区古猿地点的小型猿类化石

本文记述的云南元谋小河地区古猿地点发现的一种小型猿类。它的牙齿形态比晚中新世的禄丰粗壮池猿进步。而牙齿的某些形态介于粗壮池猿和现生长臂猿之间,它的发现为探讨现生长臂猿的起源与进货提供了新的化石依据。依哺乳动物群的初步研究,其时代稍晚于禄丰古猿地点的时代。鉴于它的形态特征和地史分布,作者将它订为一新属新种：进步滇猿Ｄｉａｎｏ ｐｉｔｈｅｃｕｓ ｐｒｏｇｒｅｓｓｕｓ ｇｅｎ．ｅｔ ｓｐ．ｎｏｖ。     

人和猿的共同祖先的活样板——俾格米黑猩猩

人和现生的猿有着共同的祖先。这种共同祖先究竟是什么样子,现在还缺乏直接的化石证据。在现生猿类中,什么猿最接近于人和猿的共同祖先,俾格米黑猩猩能否作为人和猿的共同祖先的活样板,近一时期来有着不少议论。 1929年施瓦茨(Emst Schwarz)最早对俾格米黑猩猩作了描述并把它作为普通黑猩猩(Pan troglodytes)的一个亚种。1933年库利奇(Harold Coolidge)首次发表了它的生物学的详细论文,并把它提升到种一级,定名为Pan paniscus。它的身高和普通黑猩猩差     

禄丰粗壮池猿头骨的初步观察——兼论池猿的系统关系

本文通过粗壮池猿头骨新材料的初步观察得出,它与欧洲上猿的头骨比较接近,而在某些特征上又与现生长臂猿相似。这与牙齿和颌骨研究的结果是一致的。本文还对亚洲第三纪长臂猿类与其他同时代长臂猿类的关系作了初步的探讨,并对池猿的系统关系作了论述。     

山猿之谜:直立行走的山猿是人类的祖先吗?(上)

山猿是除人科成员以外唯一能直立行走的灵长类。它从何演化而来？又为何遭淘汰绝灭？它在从猿到人的发展史上究竟占有何种地位？这是古人类学史上一个长期悬而未决的问题。山猿的发现与早期研究１８７２年法国古生物学家保尔·热尔韦（ＰａｕｌＧｅｒ－ｖａｉｓ）研究了一...     

禄丰古猿地点中国兔猴一新种

本文记述的是在云南禄丰石灰坝古猿化石产地与古猿共生的一种中国兔猴化石。这类化石以下颌骨和牙齿较纤细,牙齿的颊侧齿带较发育,牙齿狭长,齿尖锐利和臼齿咬合面的三角凹较大,下次小尖向后延伸而使下内尖和下次小尖之间有较大间隔;上臼齿的颊舌径较小等特征区别于中国兔猴厚齿种(Sinoadapis carnosus Wu and Pan.)根据以上的形态特征,作者把它订为中国兔猴一新种:中国兔猴石灰坝种Sinoadapis shihuibaensis sp.nov.。     

云南禄丰古猿生活时期的古气候初步研究

本文通过对云南禄丰古猿化石地点的沉积物进行综合分析,提出古猿生活时期的气候变迁。即石灰坝组一段为干燥而凉爽气候;二段为温暖较湿润的气候;三段为湿热的南亚热带—热带气候;四段为古猿生活时期,已转变成干湿相间的南亚热带—热带季风气候。庙山坡组(五段),初期气候—度变得相当干燥而炎热、到后期又逐渐为干温气候。     

Alae nasi electromyographic activity and timing in obstructive sleep apnea

The alae nasi is an accessible dilator muscle of the upper airway located in the nose. We measured electromyograms (EMG) of the alae nasi to determine the relationship between their activity and timing to contraction of the rib cage muscles and diaphragm during obstructive apnea in nine patients. Alae nasi EMG were measured with surface electrodes and processed to obtain a moving time average. Contraction of the rib cage and diaphragm during apneas was detected with esophageal pressure. During non-rapid-eye-movement (NREM) sleep, there was a significant correlation in each patient between alae nasi EMG activity and the change in esophageal pressure. During rapid-eye-movement (REM) sleep, correlations were significantly lower than during NREM sleep. As the duration of each apnea increased, the activation of alae nasi EMG occurred progressively earlier than the change in esophageal pressure. We conclude that during obstructive apneas in NREM sleep, activity of the alae nasi increases when diaphragm and rib cage muscle force increases and the activation occurs earlier as each apneic episode progresses.     

Mechanisms of control of alae nasi muscle activity.

Human upper airway dilator muscles are clearly influenced by chemical stimuli such as hypoxia and hypercapnia. Whether in humans there are upper airway receptors capable of modifying the activity of such muscles is unclear. We studied alae nasi electromyography (EMG) in normal men in an attempt to determine 1) whether increasing negative intraluminal pressure influences the activity of the alae nasi muscle, 2) whether nasal airway feedback mechanisms modify the activity of this muscle, and 3) if so, whether these receptor mechanisms are responding to mucosal temperature/pressure changes or to airway deformation. Alae nasi EMG was recorded in 10 normal men under the following conditions: 1) nasal breathing (all potential nasal receptors exposed), 2) oral breathing (nasal receptors not exposed), 3) nasal breathing with splints (airway deformation prevented), and 4) nasal breathing after nasal anesthesia (mucosal receptors anesthetized). In addition, in a separate group, the combined effects of anesthesia and nasal splints were assessed. Under each condition, EMG activity was monitored during basal breathing, progressive hypercapnia, and inspiratory resistive loading. Under all four conditions, both load and hypercapnia produced a significant increase in alae nasi EMG, with hypercapnia producing a similar increment in EMG regardless of nasal receptor exposure. On the other hand, loading produced greater increments in EMG during nasal than during oral breathing, with combined anesthesia plus splinting producing a load response similar to that observed during oral respiration. These observations suggest that nasal airway receptors have little effect on the alae nasi response to hypercapnia but appear to mediate the alae nasi response to loading or negative airway pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

云南元谋古猿地点的小哺乳动物化石

本文依据元谋盆地西北小河村一带古猿化石地点所产６种小哺乳动物（Ａｎｏｕｒｏｓｏｒｅｘｓｐ．,Ｌｅｐｏｎｄａｅｇｅｎ．ｅｔｓｐ．ｉｎｄｅｔ．,Ｓｃｉｕｒｏｔａｍｉａｓｓｐ．,Ｍｏｎｏｓａｕｌａｘｓｐ．,Ｂｒａｃｈｙｒｈｉｚｏｍｙｓｂｌａｃｋｉ,Ｒｈｉｚｏｍｙｉｄａｅｇｅｎ．ｅｔｓｐ．ｉｎｄｅｔ）,初步论证了几个合古猿化石地点（８６０３、８７０１、８７０４、８８０１、９００１）的时代均为晚中新世,相当于欧洲Ｔｕｒｏｌｉａｎ晚期,比禄丰古猿化石地点的时代稍晚．     

腊玛古猿和西瓦古猿的形态特征及其系统关系——下颌骨的形态与比较

本文通过禄丰腊玛古猿和西瓦古猿的下颌骨与现代大猿类和其它同时代的古猿及南方古猿类的下颌骨的比较得出:禄丰的两类古猿有不少特征与猩猩相似,因此它们可能与猩猩有较密切的关系,两类古猿可能是同一类型的雌雄个体。但另一方面,禄丰腊玛古猿又显示出一些与南方古猿相似的性状,因而另一种可能是腊玛古猿是与西瓦古猿不同的类型,它比西瓦古猿更接近于人猿的共同主干。     

腊玛古猿和西瓦古猿的形态特征及其系统关系——牙齿的形态与比较

禄丰腊玛古猿和西瓦古猿的牙齿有许多性状是一致的,但在犬齿和下前臼齿的形态上则有较大的差别,这些差别可能是两性的差别。它们与现代大猿类相比,表现出与猩猩比较相似,而与大猩猩和黑猩猩差别较大,因而禄丰腊玛古猿和西瓦古猿可能是同一类型的雌雄个体,与猩猩有较近的关系。但另一方面,与南方古猿类的牙齿相比,禄丰腊玛古猿牙齿又显示出较多的相似于南方古猿阿法种和非洲种的性状,而西瓦古猿大的犬齿与所有南方古猿类差别甚大,因此另一种可能性是禄丰腊玛古猿与西瓦古猿是不同的类型,前者是向南方古猿方向进化的早期的人科成员。     

Genioglossus and alae nasi activity in fetal sheep

The functional development of two upper airway dilating muscles, the alae nasi and the genioglossus, has been studied in fetal sheep in utero from 112-140 days gestation. Before electrocortical differentiation phasic activity was present in both muscles for long periods, mostly when breathing movements were present. After 120 days gestation phasic genioglossal and alae nasi activity occurred only during periods of low voltage electrocortical activity. During high voltage episodes there was no phasic activity and tonic activity was not sustained. Although present during periods of breathing movements genioglossus activity was rarely synchronous with the diaphragm. The alae nasi showed both respiratory and non-respiratory related activity. Hypoxia abolished both alae nasi and genioglossus activity but whereas alae nasi rapidly developed an inspiratory rhythm during 5% CO2 administration this was not the case with the genioglossus and inspiratory activity was not always seen in the genioglossus even during 10% CO2 administration. It is concluded that there are fundamental differences between the control of genioglossus and alae nasi activity in the fetal sheep. The alae nasi behaves as an inspiratory muscle responding to hypoxia and hypercapnia as would be expected but the genioglossus shows no inspiratory activity during normal unstimulated fetal breathing. Thus the neural mechanisms for activation of inspiratory activity appear to be present late in gestation. However it is possible for the genioglossus to develop an inspiratory rhythm under conditions of much increased respiratory drive.     

Activation of masseter muscles with inspiratory resistance loading

Closure of the jaw exerts traction on muscles that insert on the hyoid bone and that may stabilize or expand the pharyngeal airway. We postulated that the masseter muscles, which close the jaw, would be activated when the patency of the pharyngeal airway is threatened. We therefore measured electromyographic activation of the masseters during inspiratory resistance loading and compared it with activation of chin muscles and alae nasi in 10 normal subjects. We observed no masseter activation during quiet unloaded breathing, but as pharyngeal pressure became lower there was a significant increase in masseter activation in all subjects. The change in masseter activation relative to pharyngeal pressure was similar to that of chin muscles and alae nasi. Activation of the masseter preceded the fall in pharyngeal pressure as also occurred in the chin muscles and alae nasi. We conclude that the masseters are activated by inspiratory resistance loading and have respiratory activity similar to pharyngeal airway muscles.     

中国远古人类的进化

本文从中国人类化石的年代顺序、共同形态特征、渐进变化、形态的异样性、镶嵌性、与其他地区的基因交流和古文化证据等方面论证了中国人类进化以连续性为主,还与世界其他地区之间有渐增的基因交流。本文还附带讨论了近年云南发现的古猿化石和湖北发现的人科头骨化石。