鮈亚科鱼类下咽骨和下咽齿的形态差异及其功能适应

采用双筒解剖镜观察和手工绘图的方法,研究鮈亚科鱼类39个代表种下咽骨和下咽齿的形态特征,分析鮈亚科鱼类下咽骨和下咽齿的形态差异及其功能适应。结果显示,鮈亚科鱼类的下咽骨可以分为粗壮型、中间型和狭长型3种形态类型;下咽齿可以分为圆锥型、臼齿型、粗壮侧扁型、侧扁型和极侧扁型5种形态类型。鮈亚科鱼类下咽骨和下咽齿间呈现出多种形态组合,并相互配合共同处理不同类型的食物。下咽骨和下咽齿的形态差异为鮈亚科鱼类摄食不同类型的食物、充分利用不同的生境资源在摄食器官多样性方面提供了保证。     

Four rows of pharyngeal teeth in an aberrant specimen of the small African barb Barbus paludinosus(Cyprinidae): novelty or atavistic alteration?

An extra fourth row of pharyngeal teeth was found on both pharyngeal arches in a specmen of the small African barb, Barbus paludinosus , a species normally exhibiting three rows of pharyngeal teeth. Possible phylogenetic significance of this alteration is discussed in connection with occurrence of extra fourth rows of pharyngeal teeth in other cyprinid lineages.     

(鱼句)亚科花(鱼骨)型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。     

Developmental constraints revealed by co-variation within and among molar rows in two murine rodents

SUMMARY Morphological integration corresponds to interdependency between characters that can arise from several causes. Proximal causes of integration include that different phenotypic features may share common genetic sets and/or interact during their development. Ultimate causes may be the prolonged effect of selection favoring integration of functionally interacting characters, achieved by the molding of these proximal causes. Strong and direct interactions among successive teeth of a molar row are predicted by genetic and developmental evidences. Functional constraints related to occlusion, however, should have selected more strongly for a morphological integration of occluding teeth and a corresponding evolution of the underlying developmental and genetic pathways. To investigate how these predictions match the patterns of phenotypic integration, we studied the co‐variation among the six molars of the murine molar row, focusing on two populations of house mice (Mus musculus domesticus) and wood mice (Apodemus sylvaticus). The size and shape of the three upper and lower molars were quantified and compared. Our results evidenced similar patterns in both species, size being more integrated than shape among all the teeth, and both size and shape co‐varying strongly between adjacent teeth, but also between occluding teeth. Strong co‐variation within each molar row is in agreement with developmental models showing a cascade influence of the first molar on the subsequent molars. In contrast, the strong co‐variation between molars of the occluding tooth rows confirms that functional constraints molded patterns of integration and probably the underlying developmental pathways despite the low level of direct developmental interactions occurring among molar rows. These patterns of co‐variation are furthermore conserved between the house mouse and the wood mouse that diverged >10 Ma, suggesting that they may constitute long‐running constraints to the diversification of the murine rodent dentition.     

Comparison of Alimentary Systems in Shelled and Non-shelled Sacoglossa (Mollusca,Opisthobranchia)

The Sacoglossa (= Ascoglossa) comprise a ‘complete’ evolutionary series from species with a large shell into which the animal can withdraw completely, through species with a reduced shell covering only the visceral mass, to shell-less (‘nudibranchiate’) forms some of which have lateral wing-like extensions, parapodia, others bearing leaf-like or cylindrical dorsal appendages, cerata. The Sacoglossa are all specialized suctorial feeders, and almost all are stenophagous herbivores. Hence many anatomical adaptations to a particular food occur in the alimentary system. However, a number of characters seem to reflect phylogenetic relationships as well. Among these are presence/absence, shape, and position of pharyngeal pouches, basic shape of radular teeth, branching pattern of digestive gland, and position of anus. The classificatory significance of these characters is discussed.     

A New Miniature Characid (Ostariophysi: Characiformes: Characidae), with Phylogenetic Position Inferred from Morphological and Molecular Data

Erythrocharax altipinnis is described from the Serra do Cachimbo, Pará, Brazil. The new taxon is distinguished from all of the Characidae genera by having the pelvic bones firmly attached through the isquiatic processes; a nearly triangular hiatus in the musculature covering the anterior chamber of the swim bladder between the first and second pleural ribs (pseudotympanum); the pedunculate, notably expanded and distally compressed teeth in both jaws; circumorbital series represented by antorbital and four infraorbital bones with laterosensory canals not enclosed; a single tooth row in the premaxillary with the teeth perfectly aligned and similar in shape and cusp number; the first three branched dorsal-fin rays distinctly elongate in males; a bright red adipose and caudal fins in life; a conspicuous dark midlateral stripe extending from the opercle to the tip of the median caudal-fin rays; and by the absence of a humeral spot. The phylogenetic position of the new taxon is discussed using morphological and molecular datasets, with conflicting results of both approaches discussed. Additionally, a summarized discussion on the current problems in the Characidae taxonomy is presented and the principal biases in the morphological dataset are also discussed.     

柴达木盆地渐新世的鲤科鱼类化石

记述了首次发现于柴达木盆地早渐新世晚期至晚渐新世早期(距今27～29 Ma)的鲤科鱼类化石。材料包括咽骨、咽齿、匙骨、腹鳍骨及一些零散的鳍条。咽骨及咽齿化石与原始鲃亚科鱼类及裂腹鱼亚科裂腹鱼属鱼类的相似;腹鳍骨化石与原始鲃亚科鱼类的更相似。鲃亚科鱼类现今分布于北纬35°以南的亚洲、欧洲南部及非洲北部;裂腹鱼属鱼类分布局限于青藏高原东、南、西面的边缘区域,在柴达木盆地没有分布。柴达木盆地水系现生鱼类仅见适于高寒环境的高度特化等级的裂腹鱼亚科鱼类及鳅科高原鳅属鱼类,鱼类组成与早渐新世晚期至晚渐新世早期的不尽相同。     

Embryonic development of Python sebae - I: Staging criteria and macroscopic skeletal morphogenesis of the head and limbs

This study explores the post-ovipositional craniofacial development of the African Rock Python (Python sebae). We first describe a staging system based on external characteristics and next use whole-mount skeletal staining supplemented with Computed tomography (CT) scanning to examine skeletal development. Our results show that python embryos are in early stages of organogenesis at the time of laying, with separate facial prominences and pharyngeal clefts still visible. Limb buds are also visible. By 11 days (stage 3), the chondrocranium is nearly fully formed; however, few intramembranous bones can be detected. One week later (stage 4), many of the intramembranous upper and lower jaw bones are visible but the calvaria are not present. Skeletal elements in the limbs also begin to form. Between stages 4 (day 18) and 7 (day 44), the complete set of intramembranous bones in the jaws and calvaria develops. Hindlimb development does not progress beyond stage 6 (33 days) and remains rudimentary throughout adult life. In contrast to other reptiles, there are two rows of teeth in the upper jaw. The outer tooth row is attached to the maxillary and premaxillary bones, whereas the inner row is attached to the pterygoid and palatine bones. Erupted teeth can be seen in whole-mount stage 10 specimens and are present in an unerupted, mineralized state at stage 7. Micro-CT analysis reveals that all the young membranous bones can be recognized even out of the context of the skull. These data demonstrate intrinsic patterning of the intramembranous bones, even though they form without a cartilaginous template. In addition, intramembranous bone morphology is established prior to muscle function, which can influence bone shape through differential force application. After careful staging, we conclude that python skeletal development occurs slowly enough to observe in good detail the early stages of craniofacial skeletogenesis. Thus, reptilian animal models will offer unique opportunities for understanding the early influences that contribute to perinatal bone shape.     

用RAPD技术对特化等级裂腹鱼类亲缘关系的探讨

为确定特化等级裂腹鱼类的遗传分化关系 ,对 7种 2 2个裂腹鱼个体进行随机扩增多态DNA(RAPD)研究。从所使用的 40个随机引物中 ,选择了 37个扩增带谱清晰的引物进行分析。根据构建的分子系统树显示 ,特化等级裂腹鱼类划分为 3个属级分类单元较为合适 ,这与采用形态学特征进行系统分析所得出的结论一致。在 2 2个个体之间遗传距离矩阵中 ,最大的遗传距离指数达到了 90 38% ,此外 ,还有较多的遗传距离指数也在 6 0 %～ 90 %之间。通过分析 ,认为用RAPD标记技术来分析属级或属级以上分类单元的亲缘关系 ,具有一定的适用性。对于一些遗传差异较大的类群 (如裂腹鱼类 ) ,应用属级或属级以上分类单元的亲缘关系 ,很可能会出现个体之间遗传距离接近或达到 10 0 %的情况 ,从而无法探讨其相互之间的亲缘关系。     

Testing models of dental development in the earliest bony vertebrates, Andreolepis and Lophosteus

Theories on the development and evolution of teeth have long been biased by the fallacy that chondrichthyans reflect the ancestral condition for jawed vertebrates. However, correctly resolving the nature of the primitive vertebrate dentition is challenged by a dearth of evidence on dental development in primitive osteichthyans. Jaw elements from the Silurian-Devonian stem-osteichthyans Lophosteus and Andreolepis have been described to bear a dentition arranged in longitudinal rows and vertical files, reminiscent of a pattern of successional development. We tested this inference, using synchrotron radiation X-ray tomographic microscopy (SRXTM) to reveal the pattern of skeletal development preserved in the sclerochronology of the mineralized tissues. The tooth-like tubercles represent focal elaborations of dentine within otherwise continuous sheets of the dermal skeleton, present in at least three stacked generations. Thus, the tubercles are not discrete modular teeth and their arrangement into rows and files is a feature of the dermal ornamentation that does not reflect a polarity of development or linear succession. These fossil remains have no bearing on the nature of the dentition in osteichthyans and, indeed, our results raise questions concerning the homologies of these bones and the phylogenetic classification of Andreolepis and Lophosteus.     

Dental homologies in lamniform sharks (Chondrichthyes: Elasmobranchii).

The dentitions of lamniform sharks are said to exhibit a unique heterodonty called the "lamnoid tooth pattern." The presence of an inflated hollow "dental bulla" on each jaw cartilage allows the recognition of homologous teeth across most modern macrophagous lamniforms based on topographic correspondence through the "similarity test." In most macrophagous lamniforms, three tooth rows are supported by the upper dental bulla: two rows of large anterior teeth followed by a row of small intermediate teeth. The lower tooth row occluding between the two rows of upper anterior teeth is the first lower anterior tooth row. Like the first and second lower anterior tooth rows, the third lower tooth row is supported by the dental bulla and may be called the first lower intermediate tooth row. The lower intermediate tooth row occludes between the first and second upper lateral tooth rows situated distal to the upper dental bulla, and the rest of the upper and lower tooth rows, all called lateral tooth rows, occlude alternately. Tooth symmetry cannot be used to identify their dental homology. The presence of dental bullae can be regarded as a synapomorphy of Lamniformes and this character is more definable than the "lamnoid tooth pattern." The formation of the tooth pattern appears to be related to the evolution of dental bullae. This study constitutes the first demonstration of supraspecific tooth-to-tooth dental homologies in nonmammalian vertebrates.     

Main patterns of radula formation and ontogeny in Gastropoda

Gastropoda is morphologically highly variable and broadly distributed group of mollusks. Due to the high morphological and functional diversity of the feeding apparatus gastropods follow a broad range of feeding strategies: from detritivory to highly specialized predation. The feeding apparatus includes the buccal armaments: jaw(s) and radula. The radula comprises a chitinous ribbon with teeth arranged in transverse and longitudinal rows. A unique characteristic of the radula is its continuous renewal during the entire life of a mollusk. The teeth and the membrane are continuously synthesized in the blind end of the radular sac and are shifted forward to the working zone, while the teeth harden and are mineralized on the way. Despite the similarity of the general mechanism of the radula formation in gastropods, some phylogenetically determined features can be identified in different phylogenetic lineages. These mainly concern shape, size, and number of the odontoblasts forming a single tooth. The radular morphology depends on the shape of the formation zone and the morphology of the subradular epithelium. The radula first appears at the pre- and posttorsional veliger stages as an invagination of the buccal epithelium of the larval anterior gut. The larval radular sac is lined with uniform undifferentiated cells. Each major phylogenetic lineage is characterized by a specific larval radula type. Thus, the docoglossan radula of Patellogastropoda is characterized by initially three and then five teeth in a transverse row. The larval rhipidoglossan radula has seven teeth in a row with differentiation into central, lateral, and marginal teeth and later is transformed into the adult radula morphology by the addition of lateral and especially marginal teeth. The taenioglossan radula of Caenogastropoda is nearly immediately formed in adult configuration with seven teeth in a row.     

Prey capture in lizards: differences in jaw–neck–forelimb coordination

Fish body muscles are arranged along the vertebral column in three‐dimensional W‐shaped blocks, called myomeres. Each myomere is separated from its neighbours by a collagenous sheet, the myoseptum, and embedded in these myosepta and in positions that are conserved throughout gnathostome evolution are distinct tendons. Within teleosts these tendons often ossify. Ossification is usually intramembranous but cartilaginous structures within the tendons have also been reported. Ossified myoseptal tendons are homologous to intermuscular bones and appear only in teleosts. The phylogenetic signal of myoseptal tendon ossfication has not been tested previously, although the presence and morphology of intermuscular bones have been used to infer phylogenetic relationships. We sample over a broad phylogenetic range of teleost fishes to test for (1) the effects of phylogenetic history on the presence of intermuscular bones and (2) morphological correlations with the presence of intermuscular bones. Body shape and fin position as well as vertebral number and aspect ratio are characters that are likely to affect the distribution of stresses along myoseptal tendons, and are therefore good functional predictors of myoseptal tendon ossification. We use the summary information by Patterson & Johnson for a list of species with intermuscular bones and reanalyse the homology of intermuscular bones to myoseptal tendons. We find that there is a phylogenetic signal in the distribution of four out of six ossified tendons, but that after correcting for phylogenetic relationships there are still morphological predictors for the presence of all ossified tendons. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 607–622.     

3D morphology of pharyngeal dentition of the genus Capoeta (Cyprinidae): Implications for taxonomy and phylogeny

Capoeta is a herbivorous cyprinid fish genus, widely distributed in water bodies of Western Asia. Recent species show a distinct biogeographic pattern with endemic distribution in large fluvial drainage basins. As other cyprinids, the species of this genus are characterized by the presence of the pharyngeal bone with pharyngeal teeth. Despite this, the detailed morphology of the pharyngeal teeth, its interspecific and topologic variations, and the importance for taxonomy and phylogeny of the genus Capoeta are still not established. For the first time, a detailed comprehensive study of the pharyngeal dentition of 10 Capoeta species has been provided. The morphologic study of the pharyngeal dentition bases on the 3D microtomography and follows the purpose to evaluate the potential taxonomic and phylogenetic signals of these elements, as well as to study interspecific and topologic variations of the pharyngeal teeth. In this study, we propose a new methodology to categorize the studied pharyngeal teeth in 18 shape classes. The results of this study show that the detailed 3D morphology of the pharyngeal teeth is a useful tool for the identification of isolated teeth at the generic and/or specific level and that in certain cases, the tooth position in the teeth rows can be identified. Additionally, the preliminary analysis shows that the morphology of the pharyngeal teeth provides a potential phylogenetic signal. Both these patterns are very important for the taxonomy of cyprinid fishes and especially can be applied to fossil records.     

Evolutionary constraints in hind wing shape in Chinese dung beetles (Coleoptera: Scarabaeinae)

This study examines the evolution hindwing shape in Chinese dung beetle species using morphometric and phylogenetic analyses. Previous studies have analyzed the evolution of wing shape within a single or very few species, or by comparing only a few wing traits. No study has analyzed wing shape evolution of a large number of species, or quantitatively compared morphological variation of wings with proposed phylogenetic relationships. This study examines the morphological variation of hindwings based on 19 landmarks, 119 morphological characters, and 81 beetle species. Only one most parsimonious tree (MPT) was found based on 119 wing and body characters. To better understand the possible role of the hindwing in the evolution of Scarabaeinae, additional phylogenetic analyses were proposed based on the only body features (106 characters, wing characters excluded). Two MPT were found based on 106 body characters, and five nodes were collapsed in a strict consensus. There was a strong correlation between the morphometric tree and all phylogenetic trees (r>0.5). Reconstructions of the ancestral wing forms suggest that Scarabaeinae hindwing morphology has not changed substantially over time, but the morphological changes that do occur are focused at the base of the wing. These results suggest that flight has been important since the origin of Scarabaeinae, and that variation in hindwing morphology has been limited by functional constraints. Comparison of metric disparity values and relative evolutionary sequences among Scarabaeinae tribes suggest that the primitive dung beetles had relatively diverse hindwing morphologies, while advanced dung beetles have relatively similar wing morphologies. The strong correlation between the morphometric tree and phylogenetic trees suggest that hindwing features reflect the evolution of whole body morphology and that wing characters are suitable for the phylogenetic analyses. By integrating morphometric and cladistic approaches, this paper sheds new light on the evolution of dung beetle hind wings.     

Phylogenetic aspects of tooth and jaw structure of the Medaka, Oryzias latipes, and other beloniform fishes

Tooth structure is described for adult male, female, and juvenile Oryzias latipes (Temminck & Schlegel), the Medaka. Adult males have enlarged, unicuspid teeth posteriorly on the premaxilla and dentary. Oral teeth are smaller and more numerous in females, in which no tooth is notably larger than the others. Juveniles have numerous small teeth from about 3 mm SL (standard length) onwards. By about 16 mm SL, males begin to develop the large posterior teeth, as well as other secondary sexual characters. Lower and upper pharyngeal teeth of both males and females are fine, and in numerous even rows.
The large, posterior oral teeth of males are fully-ankylosed to the attachment bone, and, hence, are not depressible. In female Medaka, as in the Halfbeak Dermogenys pusillus van Hasselt, the oral teeth have a ring of unmineralized collagen at the base, and are not depressible. Pharyngeal teeth of Medaka have a ring of unmineralized collagen at the base, and a distinct wedge of collagen absent posteriorly, such that the pharyngeal teeth may be depressed.
Bone in adult Medaka is acellular. Incompletely mineralized teeth, acellular bone, a protrus-ible upper oral jaw, and a mobile branchial apparatus with an interhyal bone, form a complex characteristic of advanced teleosts. The Medaka differs in several ways from the model advanced teleost: absence of an interhyal bone, ascending and articular processes of the premaxilla, and the rostral cartilage, as well as presence of cartilaginous symphyses between the dentaries and premaxillae, all contribute to the fixed or nonprotrusible jaws.
Reduction in the premaxilla is a derived character within beloniform fishes for which an enlarged, beaked outer jaw is considered plesiomorphic.     

23种伞形科植物果实形态及其分类学意义

该实验采用徒手切片法对伞形科17属23种植物的果实进行了外部形态和解剖特征的观察,结果表明:伞形科果实有背腹压扁、两侧压扁和不压扁3种类型;侧棱有宽、有窄;油管的分布有棱槽单油管型和棱槽多油管型;花柱基多数为圆锥状,少数种的花柱基为扁平垫状;萼齿明显或不明显。通过进一步对属间和属内果实解剖特征的比较得出:(1)果实表面被钩刺或刚毛及果棱特征在属间差异明显,在属内表现出一致性,可作为伞形科属间分类的依据。(2)果实横切面的形状、胚乳腹面的凹凸以及萼齿的形态特征在属内种间的分类研究中有重要的意义。基于果实形态特征,编制了17属23种植物的分种检索表。     

The evolution of insect sperm − an unusual character system in a megadiverse group

Spermatozoa provide an unusual character system, with a limited number of components organized in a single cell. Similar spermatozoa occur in groups widely separated in the phylogenetic tree of Metazoa. Nevertheless, the character system contains phylogenetic information. Hexapoda have acquired spermatophores along with the switch from aquatic to terrestrial habitats, and related to this, a multitude of different sperm types. The aim of this study is a formal evaluation of the phylogenetic information content of spermatozoa. For the first time, sperm characters are coded for formal phylogenetic analyses. Different approaches are used and compared. Mainly due to a high level of homoplasy, the evaluation of sperm characters alone is insufficient for a reconstruction of the phylogeny of the group. Yet, a reliable reconstruction of the evolution of insect sperm is possible when character transformations are assessed using a phylogeny based on extensive molecular data. Important changes took place in the early evolution of Hexapoda. Sperm characters support some major clades (e.g. Hexapoda, Dicondylia, Polyneoptera, Psocodea), but important steps in the evolution are not reflected by transformations of spermatozoa, notably the rise of Pterygota or Holometabola. Important innovations are the formation of mitochondrial derivatives and the acquisition of accessory microtubules. Some features are conservative, whereas others evolved rapidly (e.g. presence or absence of the acrosome vesicle). Some groups are conservative in their sperm features (e.g. Odonata, Heteroptera), whereas the evolution of spermatozoa was distinctly accelerated in others (e.g. Ephemeroptera). The rate of evolution can change drastically in closely related groups. Profound changes in the morphologically uniform Zoraptera underline that sperm evolution can follow a pattern very different from the general somatic morphology. The mode of character reconstruction preferred here will be useful for the evaluation of specialized morphological character systems and strengthen the concept of evolutionary morphology.     

Variability in the number of tooth rows in the pharyngeal dentition of Barbus intermedius (Teleostei; Cyprinidae): genetic,hormonal and environmental factors

The variability of pharyngeal dentition in a natural population of B. intermedius and effects of genetic, hormonal and environmental factors on the number of tooth rows in the pharyngeal dentition in offspring from wild‐caught parents have been investigated. It was revealed that: (i) about 10% of fish from natural population have four‐rowed dentition instead of three‐rowed dentition characteristic for this species; (ii) the presence of the additional tooth row is not an abnormality of tooth replacement since it occurs symmetrically on both sides; (iii) occurrence of the fourth row of teeth is heritable since laboratory‐reared offspring from parents with four‐rowed dentition have the same dentition. Even if one of the parents had four‐rowed dentition the percentage of four‐rowed individuals in the progeny was significantly higher than in progeny from parents with normal (three rowed) dentition; (iv) the number of tooth rows appears to be hormonally controlled: high levels of thyroid hormone result in a decrease in the number of tooth rows to two. In contrast, deficiency of this hormone results in an increase to four rows; (v) no differences in the number of tooth rows were found in fish reared under 17°C, 24°C, 30°C and room temperature (20–26°C).