淡水豚类线粒体DNA 12S rRNA基因的序列变异及其分子系统学研究

淡水豚类４个代表属「白暨豚（Ｌｉｐｏｔｅｓ）、恒河豚（Ｐｌａｔａｎｉｓｔａ）、弗西豚（Ｐｏｎｔｏｐｏｒｉａ）和亚河豚（Ｉｎｉａ）」ｍｔＤＮＡ １２Ｓ ｒＲＮＡ基因的序列差异水平,高于其他齿鲸类科间的差异,特别是远远高于海豚总科内的科间差异。研究结果支持它们应归属于不同的科,即白暨豚科（Ｌｉｐｏｔｉｉｄａｅ）、恒河豚科（Ｐｌａｔａｎｉｓｔｉｄａｅ）、弗西豚科（Ｐｏｎｔｏｐｏｒｉｄａｅ）和亚河豚科（Ｉ     

白暨豚的舌

在现代生存的四类淡水豚中,恒河豚(Platanista gangetica)和拉河豚(Pontoporia blain-villei)的舌已有详文报道(Arvy和Pilleri,1970;Yamasaki等,1976a)。亚河豚(Iniageoffrend)的舌也在Yamasaki的文章中作为和上述二种淡水豚舌的比较而述及。白暨豚(Liptes vexillifer)的舌除陈宜瑜等(1975)曾提及外,迄今未有其他报道。鉴此,作者对白暨豚的舌作了解剖学和组织学的观察,现将研究结果报告如下: 白暨豚舌的标本取自幼体、亚成体、成体和老年个体等七头个体。为了比较,还收集了亚河豚、其它海豚类和陆生哺乳类的舌。用10％甲醛固定保存,各项量度根据固定标本测量。白暨豚舌的外形描述以NNC 7909号标本为主,以其它个体的观察为辅。其组     

白鱀豚的胃

关于鲸类胃的复杂分室早有许多详细研究。现代生存的四类淡水豚中,恒河豚Platanista gangetica及拉河豚Pontoporia blainvillei的胃在十九世纪就作过观察(Anderson,1878;Burmeister,1867),近年有详文论述(Yamasaki等,1971,1974),但对白暨豚Lipotes vexillifer及亚河豚Inia geollrensis的胃尚缺了解。白暨豚的胃仅两篇报道(Hinton和Pycraft,1922;陈宜瑜和陈炜.1975)曾提到几句,但未正确阐明其构造。鉴于白暨豚的形态研究对淡水豚类的系统发生及分类均具一定意义,现报道其食管后部和胃的解剖及组织学观察结果。     

白暨豚某些血液生化指标的测定

关于海豚和几种淡水豚类的血液学和血液生化指标国外有过研究。白暨豚(Lipotes vexillifer)血液有形成份已有过报道。本实验对白暨豚血液生化指标进行了研究,以期建立白暨豚血液正常生理生化指标,为白暨豚的临床诊断,健康监测和保健措施提供血液学参数,并且为完善淡水豚类血液学比较研究提供基础资料。     

白鱀豚的肾脏

研究了4头雄性和9头雌性白鱀豚肾脏的结构和各项指标。白鱀豚肾脏是由许多小肾组成。肾脏和小肾的各项指标随着个体体长的增加而增加。与其他3种淡水豚相比,白鱀豚成体肾脏的小肾数比恒河豚多,比哑河豚少,而与拉河豚相近。白鱀豚幼体的肾脏和小肾的各项指标与恒河豚和亚河豚相近,但成体肾脏和小肾的各项指标比上述2种淡水豚大得多。并证实鲸类动物肾脏的小肾并生群在幼体即已存在,随着个体的长大,小肾化加剧,而并不是次级融合的结果。白鱀豚小肾的髓旁肌肉带的排列并无规律,它并不构成白豚鱀所特有的排列结构。       

白鱀豚脑的解剖

作者对采自长江的三头白暨豚(Lipotes vexillifer Miller)的脑进行了解剖研究。白鱀豚的脑表现出典型的鲸脑特征。与海洋齿鲸类比较,淡水鲸科的种类普遍呈现出视觉系统的退化,这是一种生态适应的结果。从神经解剖学的观点看来,白鱀豚与亚马逊河海豚(Inia)、拉普拉塔河海豚(Pontoporia)的脑的结构是近似的,而与恒河海豚(Platanista)显着不同,     

白暨豚血液有形成分

豚类血液学的研究,自1939年诺尔(Knoll)广泛研究了鲸类胚胎的血液以来,1979年德蒙蒂(De monte)和皮莱里(Pilleri)比较了21种海豚和几种淡水豚的血液学资料。关于白暨豚(Lipotes vexillifer)的血液资料,除刘仁俊(1982)为白暨豚“淇淇”治疗外伤时,进行过白细胞分类计数外,至今未见详细的研究报道。为建立白暨豚血液生理指标和为疾病诊断提供可靠的依据,本文对白暨豚外周血液的有形成分进行了分析研究。     

白鱀豚(齿鲸亚目、白鱀豚科)的肌学研究——Ⅰ.皮肤肌附肢肌和躯干肌尾肌

肌肉系统是鲸类运动器官的基本组成,有许多适于水中运动的变化。多种齿鲸的肌学已有详文论述,如江豚(Neophocaena phocaenoides)(Howell,1927)鼠海豚(Phocaena phocaena)(Smith等,1975;1974;等,1974,1978),真海豚(Delphinus delphis)(Lawrence等,1956,1965;Mead,1975;Родионов1974;Соколов等,1974,1978)、大海豚(Tursiops truncatus)(Huder,1934;Lawrence等,1956,1965;Mead,1975;Родионов1974;Соколов等,1974,1978)、白鲸(Delphinapterus leucas) (Клейнеберг, 1964)、一角鲸(Monodon monoce- ros)(Howell, 1930)、抹香鲸(Physeter catodon)(Берэин, 1971)等。在淡水豚类,Pilleri等(1976)曾报道印河豚(Platanista indi)肌肉系统的某些特征,其他淡水豚的肌肉尚未经研究。鉴此,我们对白暨豚(Lipotes vexilifer)的肌肉系统作了较详细的解剖。解剖材料以1头体长2米,体重100公斤的雄性个体为主,以其他个体作补充。     

挽救白鱀豚

我是1997年认识“淇淇”的。“淇淇”是只白鱀豚,现住在中国科学院水生生物所——武汉“白公馆”里。全世界有4种淡水豚,除了生活在我国长江里的白鱀豚以外,还有生活在亚马逊河的亚马逊豚,生活在恒河和红河里的恒河豚和红河豚。在这4种淡水豚里,白鱀啄是最濒危的一种。它和大熊猫一样,是属于     

近年来我国关于白鱀豚Lipotes vexillifer的研究

白鱀豚是我国特有的珍贵水生哺乳动物,也是世界现存的4种淡水豚(拉河豚Pontoporia blainvillei,亚河豚Inia geoffrensis,恒河豚Platanista gangetica和白鱀豚)中存活头数最少的一种。近几年来,白鱀豚已为很多人所熟知,并像大熊猫一样,被视为我国的“国宝”。 对白鱀豚进行系统的研究工作,开始在中华人民共和国成立之后。特别是七十年代以来,我国的科学工作者对其进行了大量的调查研究。     

Molecular phylogenetics of 'river dolphins' and the baiji mitochondrial genome

It is well known that the classical river dolphins are not a natural group, but up to now the phylogenetic relationships among them are not very clear because different views have been referred from different studies. In the present study, we determined the complete nucleotide sequence of the mitochondrial (mt) genome of the baiji (Lipotes vexillifer), the most endangered cetacean species, and conducted phylogenetic analyses for the classical river dolphins based on data from cetacean mitochondrial genomes available. In our analyses, the classical river dolphins split into two separate lineages, Platanista and Lipotes+(Inia+Pontoporia), having no sister relationship with each other, and the Platanista lineage is always within the odontocete clade instead of having a closer affinity to Mysticeti. The position of the Platanista is more basal, suggesting separate divergence of this lineage well before the other one. The Lipotes has a sister relationship with Inia+pontoporia, and they together formed the sister group to the Delphinoidea. This result strongly supports paraphyly of the classical river dolphins, and the nonplatanistoid river dolphins do represent a monophyletic grouping, with the Lipotidae as the sister taxa to (Iniidae+Pontoporiidae), and is well congruent with the studies based on short interspersed repetitive elements (SINEs).     

MOLECULAR SYSTEMATICS OF RIVER DOLPHINS INFERRED FROM COMPLETE MITOCHONDRIAL CYTOCHROME-B GENE SEQUENCES

1,140 bp of the complete mitochondrial cytochrome- b gene sequences of baiji ( Lipotes vexillifer ), franciscana ( Pontoporia blainvillei ), and Ganges river dolphin ( Platanista gangetica gangetica ) were determined to address the systematic position and phylogeny of extant river dolphins with combination of homologous sequences of other cetaceans. The neighbor-joining (NJ), maximum parsimony (MP), and maximum likelihood (ML) phylogenetic analyses all identified the river dolphins into three lineages, i. e., Platanista, Lipotes , and Inia + Pontoporia . The Lipotes did not have sister relationship with either Platanista or Inia + Pontoporia , which strongly supported the referral of Lipotes to a separate family, i. e. , Lipotidae. There were very high sequence divergences between all river dolphin genera, suggesting a relatively longer period of separation time than those among other odontocete families.     

Clicking in Shallow Rivers: Short-Range Echolocation of Irrawaddy and Ganges River Dolphins in a Shallow,Acoustically Complex Habitat

Toothed whales (Cetacea, odontoceti) use biosonar to navigate their environment and to find and catch prey. All studied toothed whale species have evolved highly directional, high-amplitude ultrasonic clicks suited for long-range echolocation of prey in open water. Little is known about the biosonar signals of toothed whale species inhabiting freshwater habitats such as endangered river dolphins. To address the evolutionary pressures shaping the echolocation signal parameters of non-marine toothed whales, we investigated the biosonar source parameters of Ganges river dolphins (Platanista gangetica gangetica) and Irrawaddy dolphins (Orcaella brevirostris) within the river systems of the Sundarban mangrove forest. Both Ganges and Irrawaddy dolphins produced echolocation clicks with a high repetition rate and low source level compared to marine species. Irrawaddy dolphins, inhabiting coastal and riverine habitats, produced a mean source level of 195 dB (max 203 dB) re 1 µPa_pp whereas Ganges river dolphins, living exclusively upriver, produced a mean source level of 184 dB (max 191) re 1 µPa_pp. These source levels are 1–2 orders of magnitude lower than those of similar sized marine delphinids and may reflect an adaptation to a shallow, acoustically complex freshwater habitat with high reverberation and acoustic clutter. The centroid frequency of Ganges river dolphin clicks are an octave lower than predicted from scaling, but with an estimated beamwidth comparable to that of porpoises. The unique bony maxillary crests found in the Platanista forehead may help achieve a higher directionality than expected using clicks nearly an octave lower than similar sized odontocetes.     

Evolution of river dolphins

The world's river dolphins (Inia, Pontoporia, Lipotes and Platanista) are among the least known and most endangered of all cetaceans. The four extant genera inhabit geographically disjunct river systems and exhibit highly modified morphologies, leading many cetologists to regard river dolphins as an unnatural group. Numerous arrangements have been proposed for their phylogenetic relationships to one another and to other odontocete cetaceans. These alternative views strongly affect the biogeographical and evolutionary implications raised by the important, although limited, fossil record of river dolphins. We present a hypothesis of river dolphin relationships based on phylogenetic analysis of three mitochondrial genes for 29 cetacean species, concluding that the four genera represent three separate, ancient branches in odontocete evolution. Our molecular phylogeny corresponds well with the first fossil appearances of the primary lineages of modern odontocetes. Integrating relevant events in Tertiary palaeoceanography, we develop a scenario for river dolphin evolution during the globally high sea levels of the Middle Miocene. We suggest that ancestors of the four extant river dolphin lineages colonized the shallow epicontintental seas that inundated the Amazon, Paraná, Yangtze and Indo-Gangetic river basins, subsequently remaining in these extensive waterways during their transition to freshwater with the Late Neogene trend of sea-level lowering.     

白鱀豚脑的解剖

作者对采自长江的三头白鱀豚(Lipotes vexillifer Miller)的脑进行了解剖研究。白鱀豚的脑表现出典型的鲸脑特征。与海洋齿鲸类比较,淡水鲸科的种类普遍呈现出视觉系统的退化,这是一种生态适应的结果。从神经解剖学的观点看来,白鱀豚与亚马逊河海豚(Inia)、拉普拉塔河海豚(Pontoporia)的脑的结构是近似的,而与恒河海豚(Platanista)显著不同,这与骨骼形态上表现出的系统发育关系是一致的。       

Phylogenetic position of Platanista gangetica: insights from the mitochondrial cytochrome b and nuclear interphotoreceptor retinoid-binding protein gene sequences

The evolutionary relationship of peculiar and poorly known Ganges River dolphin with extinct and extant cetaceans has been in the state of confusion for more than a century. The close resemblance of platanistidae with some of the extinct taxon viz., Dalpiaziniidae and Waipatiidae and their sister group relationship with many of the extant lineages of cetaceans has been reported but none of the alternative hypotheses provide an unambiguous placement for this species. The present study provides insights into the molecular relationships of Platanista with other cetaceans based on comprehensive analyses of the mitochondrial cytochrome b and nuclear interphotoreceptor retinoid-binding protein gene sequences, obtained from 15 specimens of Ganges dolphin from India and Bangladesh. The mean substitution distance analysis of phylogenetically informative characters in the cytochrome b sequences suggested that Platanista gangetica is significantly closer (P<0.001) to Mysticeti than to any other group of toothed whales. However, the conventional methods of phylogenetic reconstruction supported this finding with low to moderate (41-69%) bootstrap values.