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Branching patterns of the trunk lateral line nerves were studied in 46 pleuronectiform species, representing nine families in two suborders. The dorsal fin longitudinal ramus (DFLR), derived from the main nerve (horizontal septum lateral line nerve), passed closely along the course of the middle trunk lateral line in all specimens examined, the dorsal longitudinal collector nerve (DLCN) partly coalescing with the DFLR along the arched part of the lateral line in Psettodes erumei (Psettodoidei), compared with the entire length of the latter in all other species (Pleuronectoidei). Citharidae, Paralichthyidae, and Pleuronectidae were characterized by having a simple, elongated dorsal ramule; Bothidae was unique in having more than one dorsal ramule, forming a ladder-like network and peripherally giving off numerous minute branches; Poecilopsettidae and Samaridae possessed a few, short dorsal ramules; Soleidae and Cynoglossidae were characteristic in having a dendritic dorsal ramule. Secondary modifications of the course of the middle trunk lateral line were detected by nerve information, the arched part of the lateral line having been secondarily highly elevated in some genera of Pleuronectidae, but secondarily straightened in Samaridae.  相似文献   

3.
This paper deals with the osteology of girdles in representatives of five families of Pleuronectiform fishes. A comparative account of the appendicular skeleton shows that the family Psettodidae has primitive characters that have progressively undergone reduction, resulting in the absence of basic girdle bones in other families studied. Even though the family Psettodidae has some specialized characters, its members still have so many similarities with other families that this leads to the suggestion of a common origin of all the families studied.  相似文献   

4.
本文比较了中国鲽形目8科45属94种鱼的椎骨、肋骨及肌隔骨刺等。据此(1)拟有亚目及科的检索表;(2)探讨了演化,认为鳒科最原始,鲽亚目较高,鳎亚目、尤其舌鳎科最高;(3)因本目椎骨均有脊索孔,鲆科与冠鲽科有肌隔骨刺和鲽科腹椎仅有肾脉突而无肾脉弓等原始特征,认为本目不可能起源于鲈形目而同意Amaoka(1969)起源应早于鲈形目;(4)Amaoka所示鳒属的尾下骨1是尾杆骨的脉棘,各为尾脉棘似较妥。  相似文献   

5.
A cladistic analysis of Capitata groups the families in four suborders based on medusa characters (such as manubrium morphology, position of gonads, and position and number of marginal tentacles) and hydroid characters (such as presence or absence of an oral tentacle whorl, and the different development of the tentacles of the oral and aboral whorls). On the family and generic levels, the revision results in changes which unite the separate hydroid and medusa taxonomic systems, defining genera which are not based on characters solely relating to the reduction of medusae to fixed gonophores. In those families where the reduction of the medusa can be analysed, it is shown that the reduction occurred after all synapomorphies defining the genera had evolved and usually affected individual species within a genus rather than the original species from which the other species in the genus evolved. This supports the view that medusa reduction is not in itself a valid generic character. A discussion of the theories of 'inconsistent' or 'mosaic' evolution concludes that no difference in evolutionary rate or degree of specialization can be demonstrated among taxa with free medusae and taxa with gonophores.  相似文献   

6.
The structure of skeleton of Bathylutichthys balushkini was studied and comparative analysis of it with representatives of other families of the suborder Cottoidei was performed. It was found that Bathylutichthyidae are characterized by the presence of a great number of original characters supporting its family status. They include: absence of mesethmoideum; bony canals of seismosensory system on frontale, pteroticum, and parietale and their strong reduction on infraorbitale; and absence of pterosphenoideum, intercalare, pharyngobranchiale 2, and basihyale. At the same time, Bathylutichthyidae retain a considerable number of generalized specific features: location of parietalia laterally to supraoccipitale and absence of their joint between themselves, presence of mesoptergoideum and basibranchialia 2 and 3. Cladistic analysis based on osteological characters and characters of the seismosensory system of 11 families of Cottoidei demonstrates that Bathylutichthyidae are combined into one group with families Rhamphocottidae, Agonidae, Psychrolutidae, Cyclopteridae, and Liparidae occupying an intermediate position between Psychrolutidae and the two last families. The cladogram obtained does not support the point of view of existence in the suborder Cottoidei of an independent superfamily Cyclopteroidea, including families Liparidae and Cyclopteridae.  相似文献   

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Comparative study of representatives of the family Scophthalmidae was performed. The topography of head sensory canals was studied; some osteological specific features and data on pyloric caeca were specified; and the presence of an outgrowth of operculum pupillare in several species was described. The found differences have different level of taxonomic significance; the most informative is the structure of the seismosensory system, in whose specific features a vector of reduction trend of evolutionary transformations is traced. On the whole, its structure agrees with present concepts of the group phylogeny. The genus Scophthalmus is characterized by the greatest number of plesiomorphies. No differences were found between the Atlantic and Black Sea representatives of the species S. maximus. Lophopsetta aquosa is considerably separated by reduction of the infraorbital canal of the eyed side. The similarity of Z. regius and Z. punctatus and the difference of both species from Phrynorhombus norvegicus support assigning Z. regius to the genus Zeugopterus. P. norvegicus is characterized by several apomorphies, which provides the given taxon the most advanced position in the family.  相似文献   

9.
云南蕨类植物的物种多样性和区系组成   总被引:1,自引:0,他引:1  
在一定实地调查和分类的基础上,采用统计分析及区系地理分析法,对云南地区蕨类植物进行研究。结果表明:云南地区共有蕨类植物60科193属1 530种(包括变种和变型),科、属、种分别占中国蕨类植物科总数的58.8%,属的83.9%和种的95.2%;在这60个科中含30种以上的有13个,含5个属以上的有11个,分别占该蕨类植物区系属、种数的56.5%和79.2%,特别是鳞毛蕨科、蹄盖蕨科、水龙骨科和金星蕨科,这4个科共拥有70属761种,分别占总属数、总种数的36.3%、49.7%;193属中含30种以上的有11个,分别占总属、总种数的5.7%和41.7%,最具优势的是鳞毛蕨属和耳蕨属、蹄盖蕨属、铁角蕨属、卷柏属,这5个属共有403种,占总种数的26.3%;该区系中无云南特有科,但具有4个亚洲特有科:雨蕨科、稀子蕨科、柄盖蕨科和骨碎补科;该区系以热带、亚热带性质为主,科的区系成分中热带亚热带分布的科占66.6%,热带成分的属有112个,占68.7%(除世界分布类型);该区系是东亚地区蕨类植物区系的重要组成部分,东亚分布31属和中国特有分布6属,分别占总属数(除世界分布属外)的19.0%和3.7%;该地区蕨类植物区系与西藏、台湾具有共同的区系起源和物种分化形成的背景,属的相似性系数约为70%,种的相似性系数约为30%,均起源于热带亚热带地区;属的热带区系成分与温带区系成分所占比例分别为68.7%和27.6%,存在一定的区系过渡性;该区系科的分化强度为3.2,属的分化强度为7.9,在科、属水平上均表现出较强的区系分化特征。  相似文献   

10.
Systematics of the genera of Bodotriidae (Crustacea: Cumacea)   总被引:1,自引:1,他引:0  
The cumacean family Bodotriidae includes 382 species in 31 genera grouped in three subfamilies: Bodotriinae, Mancocumatinae and Vaunthompsoniinae. Generic diagnoses are based on few characters that often have overlapping states among genera, complicating the understanding of the relationships within the group. The goals of this study are to illuminate the phylogenetic relationships among the genera of the Bodotriidae using morphological characters and to review the systematics of the family. For this purpose, all species within each genus were studied from the literature to code all the variability of genera for 109 variable morphological characters. Phylogenetic analyses show that there is independent reduction of the pleopods in two clades from a plesiomorphic state of five pairs, while the number of exopods of peraeopods has been reduced gradually in more derived groups of bodotriids. The subfamily Bodotriinae is the most derived and the Vaunthompsoniinae the most basal, and is paraphyletic with the Mancocumatinae embedded within it. No discriminatory characters were found between the subfamilies Mancocumatinae and Vaunthompsoniinae and they are not clearly separated in the phylogeny. Mancocumatinae is synonymized with Vaunthompsoniinae and all the genera of the former Mancocumatinae should be included within Vaunthompsoniinae. Analyses of character evolution justify a few other taxonomic changes. All genera were redescribed based on all the coded characters and a complete list of all valid species for each genus is included. Finally, dichotomous keys for identification to genus level are provided.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 151 , 1–58.  相似文献   

11.
The anatomy of the middle ear region of the skull is described for the families of the Avian orders Pelecaniformes and Ciconiiformes. Emphasis is placed on the foramina and paths of the nerves and blood vessels. The morphology of the basicranium and quadrate is also discussed. Comparative analyses of the characters are used to assess taxonomic conclusions.
Extant Pelecaniformes consist of six families, four of which are monogenic: Phaethontidae, Pelecanidae, Anhingidae and Fregatidae; one is composed of two genera: Sulidae; and the last has three genera: Phalacrocoracidae. Several years ago a relationship was suggested which would ally the Phaethontidae and the Fregatidae. While these families share several non middle ear characters the anatomy of the middle ear is not compatible with any particular relationship. Indeed, several obvious differences are described. The data presented here are consistent with the idea that the Phaethontidae and the Fregatidae each form a separate group of Pelecaniform birds, with the rest of the families forming a third group. Several differences in the middle ear region of the species of Anhingidae suggest that the family may be composed of two genera.
While sharing many Ciconiiform characters the Ciconiidae have been shown not to be as closely related to the Ardeidae as they are to other families of Ciconiiformes. In addition, evidence is presented to support the recent idea that the three species of ibis (I. ibis, I. cinereus and I. leucocephalus ) be united within the genus Mycteria. Also supported is the notion that Balaeniceps is Pelecaniform in character, and not Ciconiiform.  相似文献   

12.
Abstract. The phylogenetic relationships within the Order Aplousobranchiata (Ascidiacea) are largely unexplored. In this work, we study the phylogenetic status of the genera Clavelina and Pycnoclavella. Traditionally, both genera had been included in the family Clavelinidae, until the new family Pycnoclavellidae was defined, removing the genus Pycnoclavella from Clavelinidae. Not all authors accept the validity of Clavelina and Pycnoclavella as distinct genera, let alone their belonging to different families. In addition, the assignment of species to these genera, as well as to the genus Archidistoma , has been controversial. We analyzed sequences of the mitochondrial gene cytochrome c oxidase subunit I belonging to ten species of Pycnoclavella (including several formerly assigned to Archidistoma and Clavelina ), 11 species of Clavelinidae, and ten species of other aplousobranch genera belonging to seven families, plus two outgroups. Two different tree construction methods (maximum likelihood and Bayesian inference) showed similar results. Pycnoclavella and Clavelina appeared in distinct clades but formed a monophyletic group relative to representatives of the main families of the order Aplousobranchiata. Our phylogenetic results indicate that both genera are valid but should be included within a single family, with the name Clavelinidae having precedence. The monotypic clavelinid genus Nephtheis branches in our trees within the clade of the genus Clavelina. Our results also confirm that some forms assigned to Archidistoma and Clavelina have been misplaced and belong to the genus Pycnoclavella. Pycnoclavella martae n.sp. is described.  相似文献   

13.
A detailed comparison of the vegetative and reproductive structures in Laurus nobilis and L. azorica is presented. Most of the characters used by authors to differentiate the two species show a marked degree of overlap. The only characters for which absolute differences could be demonstrated were the leaf tomentum and chromosome number. The fossil record is discussed. None of the taxa referred to Laurus can be accepted as representatives of the genus. However, an examination made of leaf-remains known as Laurophyllum abchasicum established that these belong to the genus Laurus.  相似文献   

14.
Based mainly on morphological characters, the phylogenetic relationships among genera and some species groups of the neotropical family Callichthyidae were examined. A study of the osteology of a generalized callichthyid, Callichthys callichthys (Linnaeus), with detailed comparisons among representatives of the remaining genera in the family, is presented and used as a basis for the phylogenetic analysis. A single most parsimonious tree supported the monophyly of the family Callichthyidae based on 28 derived features and the division of the family in the subfamilies Corydoradinae and Callichthyinae. In the subfamily Corydoradinae, the genus Aspidoras is the sister-group of the clade formed by Corydoras plus Brochis. Five derived features support the monophyly of this clade and four support the monophyly of Brochis. No characters, however, were found to support the genus Corydoras. In the subfamily Callichthyinae, Dianema and Hopbstemum are sister-taxa. Megalechis represents the sister-group of Dianema plus Hoplosternum and Lepthoplosternum represents the sister-group to Megalechis plus Dianema plus Hopbstemum. Finally, Callichthys is considered the least derived member of the subfamily, and is hypothesized as the sister-group of the remaining species. A key to all callichthyid genera is provided.  相似文献   

15.
中国两栖、爬行动物更新名录   总被引:1,自引:0,他引:1  
本文在2015年发表的爬行动物名录及同年《中国两栖类信息系统》发布的两栖动物名录的基础上, 通过整理新发表的分类学研究及先前名录遗漏的部分早期文献, 更新了截至2019年底中国现生本土两栖、爬行动物物种名录。2015-2019年间, 中国两栖动物新记录1科, 新描述2属, 恢复1属有效性, 新记录1属, 新描述或恢复有效种74种, 新增国家纪录18种; 另6属、8种的有效性未得到近年研究证据支持(在此视为次定同物异名而未做收录, 后同)。同期, 中国爬行动物新恢复5科, 新描述1亚科, 新描述1属, 恢复3属有效性, 新记录3属, 新描述、恢复或提升有效种43个, 新增国家纪录10种; 另有5属、4种的有效性未得到近年研究证据支持, 并移除1属、4种在我国的分布纪录。此外, 通过整理2015年前文献, 爬行动物增补3属, 提升3亚种至种级地位, 增补国家新纪录3种, 另有3属、2种的有效性未得到近年研究证据支持, 同时移除1种在我国的分布纪录。综上, 截至2019年底, 我国共记录现生本土两栖动物3目13科62属515种(蚓螈目1科1属1种, 有尾目3科14属82种, 无尾目9科47属431种), 爬行动物3目35科135属511种(鳄形目1科1属1种, 龟鳖目6科18属34种, 有鳞目蛇亚目18科73属265种、蜥蜴亚目10科43属211种)。此外, 本文还对先前名录中部分爬行动物的中文名提出了修改建议, 建议恢复部分物种的惯用中文名。2015-2019年, 新物种及新纪录已知物种数量占现两栖、爬行动物物种总数的17.1%和10.2%。近年来, 我国发表的两栖、爬行动物新物种和已知物种的新纪录数量持续增加, 分类体系也在研究中不断完善, 建议今后及时地进行阶段性总结, 同时对存在的问题提出讨论, 以推动中国两栖、爬行动物分类学研究工作的进一步开展。  相似文献   

16.
浙江北雁荡山蕨类植物区系特征分析   总被引:1,自引:0,他引:1  
通过标本和文献查阅以及野外调查,对浙江北雁荡山蕨类植物的区系组成和分布区类型进行了分析.结果显示:北雁荡山共有蕨类植物37科71属156种(含种下分类群);以单种和寡种分布的科和属所占比例最大,分别占总科数和总属数的75.7%和91.5%.该区域蕨类植物科的分布区类型以世界分布型和泛热带分布型为主,分别有14和20科,占总科数的37.8%和54.1%;热带成分总计22科,占总科数的59.5%,而温带成分仅1科.属的分布区类型可划分为9类型2亚型,包含世界分布型17属、热带分布型47属、温带分布型7属;其中,泛热带分布型属数量最多区28属),占总属数的39.4%.种的分布区类型以东亚分布型最多(93种),其中,中国-日本分布亚型有65种,占总种数的41.7%.中国特有种有21种(占总种数的13.5%),其中2种为仅分布于本区域的特有种,分布类型以华东-华南分布最多.由分析结果可见:北雁荡山蕨类植物具有组成丰富、区系起源古老、地理成分多样、热带区系特征明显及特有种数量匮乏等特点,但与周边区域蕨类植物分布有紧密联系.  相似文献   

17.
The phylogenetic relationships of the family Pinguipedidae plus the genus Cheimarrichthys von Haast, 1874, were studied to redefine the family. Based on a phylogenetic analysis using derived characters belonging to 21 transformation series, accepting the monophyly of Pinguipedidae plus Cheimarrichthys provisionally for the operational procedure of the analysis, it was hypothesized that Cheimarrichthys is not closely related to Parapercis Bleeker, 1863, although these genera had been considered as having a close affinity. Although the Pinguipedidae and Cheimarrichthys share nine derived characters, it was determined that these characters are also found in other trachinoid families. In addition, several families, such as the Leptoscopidae, Uranoscopidae, and Trichodontidae, have many more derived characters in common with Cheimarrichthys than the pinguipedids have with that genus. The conclusion drawn here is that it is not parsimonious to recognize the monophyly of the Pinguipedidae and Cheimarrichthys based on these nine derived characters, and that these characters are not compelling enough to link these groups. The redefined Pinguipedidae is proposed to include the following five genera: Parapercis, Prolatilus Gill, 1865, Pinguipes Cuvier, 1829, Pseudopercis de Miranda-Ribeiro, 1903, and Kochichthys Kamohara, 1960. Cheimarrichthys, excluded from the Pinguipedidae, is put into its own family, Cheimarrichthyidae.  相似文献   

18.
分析论述了浙江省淳安县千岛湖库区的种子植物区系。该区共有野生种子植物114科、401属、666种,其中裸子植物有4科6属6种,被子植物中单子叶植物11科66属95种,双子叶植物99科329属565种。科的分布区类型以世界广布、泛热带分布和北温带分布居多,热带分布的科多于温带分布的科(48/28)。属的数量统计显示该区单种属和寡种属共有393属,占总属数的71.51%,说明本地区植物组成较为分散。属的分布区类型以泛热带分布最多、共94属,占总属数的23.44%;其次是北温带分布及其变型、有56属,占总属数的13.97%。热带分布与温带分布的属数相当(180/171)。通过大陆和岛屿种子植物区系的分析比较得出,生境片段化可能已经影响了千岛湖库区植物区系的分布。  相似文献   

19.
The suspensor is a unique embryonic region that connects the embryo to the seed coat. In many angiosperms, the suspensor attains remarkably diverse morphological forms ranging from vesicular single-celled (Orchidaceae) to differentiated multicellular structures (Fabaceae). These variations may be specific to the genera and species of different families, and even members of a single family show a fair amount of diversity in suspensor morphology. Clear differences in the structure of plastids were observed due to type and phylogenetic relationship of angiosperm suspensors. In present study, diversity within suspensor plastids was evident in representatives of four Crassulaceae genera. In more closely related genera this difference was smaller, while in genera less related to each other, it was larger. In this family a decreasing gradation in the size and complexity of plastids from the basal cell to the chalazal suspensor cells and the embryo proper was found. In angiosperms, also a gradient in the size of nuclei and the degree of ploidy along the micropyle-chalaza axis embryo exists. Such a gradient can also be correlated with the gradient of plastids and the variation in plasmodesmata diameter along the micropyle-chalaza axis in the Crassulaceae embryo.  相似文献   

20.
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