淡水豚类分子系统发生的研究

测定了白暨豚和恒河豚细胞色素ｂ基因３０７ｂｐ的ＤＮＡ序列,并与其它鲸类的相应序列合并,分析了淡水豚类（恒河豚、印河豚、白暨豚、亚河豚和弗西豚）的系统学位置和系统发生。淡水豚类不同属间的序列差异已达到或超过了其它齿鲸类科间的差异水平,因此它们分别归属于不同的科,即恒河豚科、白暨豚科、亚河豚科和弗西豚科。系统发生分析支持淡水豚类和海豚类之间具有下述的关系：（恒河豚科（（白暨豚科（亚河豚科,弗西豚科））海豚总科））。即淡水豚的４个科中,恒河豚科是最早分化的一支,其次是白暨豚科,然后是亚河豚科和弗西豚科的分化。白暨豚科和亚河豚科＋弗西豚科组成海豚总科的姊妹群,并与海豚总科一同组成海豚下目。恒河豚与其它淡水豚类间无直接的亲缘关系。淡水豚类是并系的。把恒河豚类独立为恒河豚总科是合理的。初步认为有理由把白暨豚类也作为一个总科级的支系。恒河豚和印河豚间的序列差异极小,两者可能只是同一个种的２个亚种。     

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     

白既豚的骨骼和分类位置

1918年Miller比较了白既豚Lipotes vexillifer与亚河豚Inia geoffrensis的头骨与颈椎,认为白既豚是亚河豚的近亲,归属亚河豚科Iniidae。1960年,Fraser和Purves比较与鲸类听觉器官有关的骨骼及气窦(air sinus),把白既豚列入亚河豚亚科Iniinae。1972年,Brownell和Herald在关于白既豚的综述中报告其椎骨数两例,同时发表了头骨、牙齿及鼓围耳骨(tympaao-periotic)等照片。1973年,Kasuya根据鼓围耳骨的研究仍认为白既豚属于亚河豚科。1975年,陈宜瑜和陈炜报告其骨骼的某些特征,Bree和Purves报道对国外仅有三个头骨的测量。此六文中,对其骨髂的记述尚有疏误;对其分类归属都墨守Miller的观点,仅分类阶元有科或亚科之别。此外,在分类位置问题上,周开亚(1958)、寿振黄     

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。     

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。     

白暨豚“功能性灭绝”背后的思考

2006年11月～12日由中国科学院水生生物研究所、农业部长江渔业资源管理委员会和瑞士白暨豚保护基金会组织了一次“长江淡水豚类考察，对自宜昌至上海的长江中下游江段进行了为期38天的往返搜索。2007年8月8日《生物学快报》发表了此次考察的结论性报告，正式宣布此次考察没有发现白鳖豚，认为白暨豚在长江中“可能即将灭绝”（“likely to beextinct”）。     

人工饲养下亚河豚的行为生物学研究

本文报道了２头雄性亚河豚“Ｖａｔｅｒ”和“Ｂａｂｙ”的各种行为。研究表明,饲养池的大小直接影响豚的行为;由于亚河豚和白豚生存的环境不同,导致了它们身体结构的差异,从而表现出不同的行为方式。     

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,     

饲养条件下白豚的游动及呼吸行为观察

１９９２年５月到１０月，我们对养于中国科学院水生生物研究所白豚馆的１头白豚进行了游动和呼吸及其昼夜节律的研究。根据游速测定将其游动分为慢速游、中速游和快速游３类。慢速游为最基本的游动方式，其１天中每小时所占的时间份额无明显的昼夜差异，而中、快速游则白天显著多于夜晚；因此，我们所观察到的白暨豚夜晚运动减缓的节律是中、快速游减少的结果。白豚１天中平均呼吸频率为１０６．０５次／ｈ（１．７７次／ｍｉｎ）。其平均呼吸间隔时间为３０．６２±２４．５５ｓ，范围１．０４—３１６ｓ。白豚的呼吸模式为１次长间隔呼吸之后伴随１—８次短间隔呼吸。慢速游不会明显提高白豚的呼吸频率，而中、快速游将使呼吸频率显著提高，反映出中、快速游会使白豚的能耗显著增加。     

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.     

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.     

Molecular phylogenetic examination of the delphinoidea trichotomy: congruent evidence from three nuclear loci indicates that porpoises (Phocoenidae) share a more recent common ancestry with white whales (Monodontidae) than they do with true dolphins (Delphinidae)

Porpoises (Phocoenidae), dolphins (Delphinidae), and the two species of Monodontidae (beluga and narwhal) together constitute the superfamily Delphinoidea. Although there is extensive evidence supporting the monophyly of this superfamily, previous studies involving morphology, as well as sequence analysis of mitochondrial genes, have failed to yield a clear picture of the relative relationships within the group. Here we present the first examination of this issue from the perspective of single-copy nuclear genes at the DNA sequence level. The data involve three such loci: von Willebrand factor (vWF), interphotoreceptor retinoid binding protein (IRBP), and lactalbumin. The vWF and IRBP data sets consist of protein-coding fragments, whereas the sequenced lactalbumin fragment is predominately intronic. All phylogenetic analyses involving at least one representative from each of the three Delphinoidea families congruently support a beluga/porpoise clade. The levels of sequence divergence for most of these data appear to roughly concur with a paleontological date for the radiation of the Delphinoidea at 11-15 MYA but, in agreement with mitochondrial DNA sequence analyses, suggest that the extant major groups of cetaceans radiated approximately 25 MYA, 10 million years later than inferred from paleontological data.     

Ultrastructure of enamel and dentine in extant dolphins (Cetacea: Delphinoidea and Inioidea)

Longitudinal and cross sections of teeth from 17 species of the Recent dolphins (Delphinoidea and Inioidea) were examined under scanning electron microscope to study the arrangement and ultrastructure of dental tissues with reference to phylogenetic and functional constraints. For most species, enamel had a simple bi-layered structure of radial enamel and an outer layer of prismless enamel. The outer prismless layer varied from 5 to 30 % of enamel thickness. The enamel of Burmeister’s porpoise (Phocoena spinipinnis) was entirely prismless. The prisms had an open sheath; tubules and tuft-like structures were common at the enamel-dentine junction. Cetacean dentine was characterized by irregularly distributed dentinal tubules in a relatively homogenous dentinal matrix. Radial enamel was observed in all Delphinoidea and in the franciscana (Pontoporia blainvillei), whereas the Amazon river dolphin (Inia geoffrensis) had prisms organized in Hunter–Schreger bands. HSB in enamel are regarded as a device for resisting propagation of cracks. These may occur due to increased functional demands, possibly related to the hardness of the species diet. Simplification in tooth shape and reduced biomechanical demands plausibly explain the primitive radial organization among delphinoids and Pontoporia. The HSB structure in the Amazon river dolphin, similar to those of extinct archaeocetes, seems to have secondary functional implications. However, the distribution of HSB in more-basal odontocetes is too poorly known to judge whether the HSB of Inia are a retained plesiomorphic feature or convergence.     

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).     

鲸类分子系统学研究进展

综述了近年来分子生物学标记技术在鲸类系统学研究中的进展。分子生物学证据支持鲸目与有蹄类之间有较近的亲缘关系,并支持鲸类的单系起源,但鲸类不同类群(须鲸类、抹香鲸类及不包括抹香鲸类的齿鲸类)之间的系统发生关系仍存在争议。抹香鲸类到底与须鲸类还是与其它齿鲸类有更近的亲缘关系,不同的分子生物学家所得到的结果并不一致。此外,分子生物学技术还被用于解决须鲸亚目和齿鲸亚目内科间以及科内种间的系统发生关系,特别是齿鲸亚目的海豚科、鼠豚科和淡水豚类。通过分子标记技术来研究鲸类种下的遗传结构是鲸类分子系统学研究中的一个新热点,使用的标记主要是mtDNA控制区、核DNA微卫星和主要组织相容性复合体(major histo-compatibilitv complex,MHC)等。     

GEOGRAPHIC VARIATION IN RATES OF VOCAL PRODUCTION OF FREE-RANGING BOTTLENOSE DOLPHINS

Echolocation and whistle production, group sizes, and activities of free-ranging bottlenose dolphins were compared across four regions (Wilmington, NC Intracoastal Waterway [ICW]; Wilmington coastline; Southport, NC coastline; and Sarasota, FL inshore waters). Number of whistles and echolo-cation bouts differed significantly across sites. Dolphins whistled significantly more in Southport than in the other sites, independent of group size. Unlike at the other sites, dolphin vocalizations in Southport did not vary significantly across activities; this difference may be due to the fact that Southport animals were often found behind shrimp-trawling vessels, which may affect their behavior. Resident Sarasota dolphins vocalized significantly less than dolphins at the NC sites. At most sites, echolocation production per dolphin decreased as group size increased, supporting the idea that echolocation information is shared. In the ICW and Sarasota, echolocation production per dolphin was highest while feeding, indicating that echolocation is used in foraging. At all sites but Southport, whistle production per dolphin was highest while socializing, indicating that whistles are used in communication. Overall, these data show that dolphins have different vocal and activity patterns at different sites; thus, caution should be used when extrapolating results from one study site to another.     

Feeding aggregation and aggressive interaction between bottlenose (Tursiops truncatus) and Commerson’s dolphins (Cephalorhynchus commersonii) in Patagonia,Argentina

We report the first recorded interactions between bottlenose dolphin (Tursiops truncatus) and Commerson’s dolphins (Cephalorhynchus commersonii). The diurnal behavioral patterns of bottlenose dolphins in Bahía Engaño, Argentina, were similar to those described for other coastal populations around the world. The majority of the feeding bouts were recorded near the mouth the Chubut River. When not feeding near the river, bottlenose dolphins generally swam along the coast, and interactions with Commerson’s dolphins were recorded very close to the shore on two occasions during a 3-year period. In the first event, both species were feeding on a fish school. The second interaction was aggressive in nature, involving one juvenile and three adult bottlenose dolphins with several Commerson’s dolphins. Two of the adult bottlenose dolphins attacked the Commerson’s dolphins. We propose that the observed behavior represented defense of the juvenile bottlenose dolphin.