Show me your tenent setae and I tell you who you are – Telling the story of a neglected character complex with phylogenetic signals using Leiodidae (Coleoptera) as a case study

The tarsal setae in 97 species of Leiodidae and eight outgroups were examined using SEM imaging and dissections. Modified adhesive setae present in males are referred to as “male tenent setae” (MTS). In most cases, dilated tarsomeres were associated with MTS, which were always present on the protarsi and sometimes the mesotarsi. MTS are reported for the first time on the mesotarsi of Leptodirini and on the metatarsi in two genera of Sogdini. Contrary to reports in the literature, the reduction in the number of the MTS bearing mesotarsomeres is considered a derived condition. Both sexes of Leptinus (Platypsyllinae) have modified setae (referred to as tenent setae in the literature), probably related to their specialised association with mammals, and a patch of MTS was recognized for the first time among those modified setae among males. Four main types of MTS are recognised: (1) a plesiomorphic discoidal type that has a shaft with a round cross-section and maintains a similar diameter throughout its length until forming the expanded discoidal terminal plate; (2) a minidiscoidal type, similar to discoidal but with a relatively small terminal plate, found in Cholevinae; (3) a conical type, present in Leiodinae (excluding Estadiini) where the shaft increases in diameter until forming the terminal plate; and (4) a spatulate type, where an even wider terminal plate has a lateral projection, derived from the conical form and synapomorphic for the leiodine tribes Pseudoliodini, Scotocryptini, and possibly Agathidiini.     

大熊猫颅骨、下颌骨及牙齿特征在进化上的意义

本文对大熊猫颅骨形态及牙齿结构进行了研究,认为大熊猫与始熊猫的裔征不同于熊科成员,应单列一大熊猫科(Ailuropodidae)。在大熊猫种系进化中,它们的形态与机能是统一的。不同种类的形态特征,又是在适应环境中逐渐产生的。根据这个认识,我们把大熊猫的进化历程可划分为始发期、成长期、鼎盛期和衰败期。     

How morphology of artificial organisms influences their evolution

The purpose of this work is to study virtual populations of artificial organisms with their genotype, morphology, mechanism of motion, search and competition for food, reproduction, mutations. The genotype determines the phenotype (morphology), while morphology determines efficiency of motion and success in the search for food in the competition with other individuals; sufficient amount of food allows reproduction. Ensemble of these elements constitutes the minimal model to study natural selection of artificial organisms. Considering only some of them, as it is often the case in artificial life models, can be used for the optimization of some properties (for example, robot's gait or embryo's form) but not to study natural selection in the evolutionary context.Artificial organisms are considered in this work in the form of polygons (triangles) on the plane. Their genotype is given by three positive numbers associated to the vertices and their morphology is determined by the lengths of the sides equal the sum of the numbers in the adjacent vertices. Behavior of the individuals and their success in the search for food depend on their morphology. More efficient individuals will reproduce more than the others and will transmit their advantageous variations to their offsprings. Hence we can observe how natural selection chooses more efficient morphology and how it evolves due to random mutations.We develop an individual based model where the individuals recognize food and move to it with the speed determined by their morphology (and not prescribed in the algorithm). If they have enough food, they survive and reproduce. Therefore morphology and evolution are tightly interconnected and should be studied together. Dynamics of such populations appears to be different from the dynamics described by conventional models of competition and evolution of species. In particular, a new phenotype can emerge due to a different strategy of foraging (related to a different morphology) and not only due to a difference in consumed resources with the existing phenotype. We also observe that realization of Cope's rule (increase of body size in the process of evolution) can depend on parameters of the model.     

Changing Minds? Implications of Conceptual Change for Teaching and Learning about Biological Evolution

Learning about biological evolution presents particular challenges for students. Barriers to learning come in the form of students’ prior conceptions that conflict with the scientific perspective of biological change. Theory and research from developmental and educational psychology provide insight into these barriers. Helping students understand evolution is not simply a matter of adding to their existing knowledge, but rather, it means helping them to see the world in new and different ways. Theoretical perspectives on creating change in students’ conceptions have implications for teaching about biological evolution. The material is based upon work supported by the National Science Foundation: Grant #0635629 to all three authors, #0133446 to the second author, and #0540152 to the third author.     

Rib fabrication in Ostreoidea and Plicatuloidea (Bivalvia,Pteriomorphia) and its evolutionary significance

Ribs of Ostreoidea and Plicatuloidea are defined as antimarginal, that is, perpendicular to the margin throughout growth. Morphogenetically, these ribs are unique, since, unlike radial ribs, they are secreted by a homogeneous mantle margin. Based also on the reconstructed shell secretion cycle in Bivalvia, we propose that ribs of Ostreoidea and Plicatuloidea are formed by a mantle margin which, upon extension from the shell margin, stretches and folds by taking the preformed ribs as templates. In extending perpendicular to the margin (as in all Bivalvia growing isometrically), such a mantle extends the rib pattern antimarginally. Ribs of this kind are purely mechanical structures, as their arrangement depends on the mechanical properties of the mantle and on the environmental conditions. This explains the high irregularity of such ribbing patterns. The presence of antimarginal ribs in both the Ostreoidea and Plicatuloidea sheds light on their origin. The first known oyster, Actinostreon cristadifformis, probably derived from an antimarginally ribbed Prospondylidae gen. indet. in the Late Permian or Early Triassic. Antimarginally ribbed Triassic species formerly included in Placunopsis originated both the Dimyidae Atreta in the Late Triassic and Enantiostreon in the Mid Triassic, which was transitional to Plicatulidae. Therefore, Dimyidae and Plicatulidae are closely connected and grouped under Plicatuloidea, to which Ostreoidea is phylogenetically unrelated.     

Morphology and the evolution of cycadeoidales

OneCycadeoidea stem one cycadeoidalean gynoecium and a bisporangiate cone attached to a slender cycadeoidalean trunkCycadeoidella japonica Ogura from the Cretaceous of Japan shows well-preserved internal structure that provides evidence for a better understanding of the morphological architecture of the cycadeoidalean plant. Structural details of the cone were confirmed. The ovule has an intergument enclosing a free nucellus and a thin outer envelope. Both reproductive and vegetative structures support the medullosan affinity of Cycadeoidales. The cone is interpreted as a compressed fertile shoot. Axillary cones characterizing some Cretaceous genera such asCycadeoidea andMonanthesia consist of a lateral shoot subtended by a frond that is the first leaf of the cone shoot itself. The origin of axillary buds in the Cycadeoidales is discussed. Heterochrony may have mediated the morphological changes that resulted in the establishment of the Cycadeoidales.     

中国古代人骨体质人类学的研究进展与展望

近10年来,中国古代人骨遗存的体质人类学研究迅猛发展,研究内容的广度和深度已完全超越了上世纪以人种类型分析为主的情况。这些研究涉及到古代人群的演化、古代疾病与健康、文化习俗相关的骨骼异常、骨骼功能适应、古人口学等多个领域,并积累了一批重要的古代人群体质人类学数据。这些研究工作丰富了我们对东亚地区全新世人群演化历史的认识,体现了多学科的研究理念和研究方法的创新。本文对我国近10年来全新世古代人骨材料的体质人类学研究进展进行了回顾和展望。     

Proventricular structure in solitary bees (Hymenoptera: Apoidea)

Proventricular structure, analyzed by scanning electronic microscopy, is compared among 28 species of solitary bees representing four families. Observations on the shapes of proventricular folds and on hair-like cuticular projections are presented, discussed, and suggested as useful to future studies of bee systematics.     

Anatomical and functional specializations of the human gluteus maximus

Many anthropologists and anatomists have claimed that the human gluteus maximus is a functionally and structurally unique muscle, but there is not agreement on the actual characteristics of the muscle which do distinguish man from other primates. In this paper the superficial gluteus in a wide range of primates is discussed and those traits entirely unique to man are identified. The morphological specializations of the human gluteus maximus are confined to its cranial portion. This part is thicker in man than in any other primate; it has a new and firm origin, a modified ascending tendon of insertion, and an additional new insertion into the overlying fascia lata. Such changes improve the ability of the gluteus maximus to participate in controlling lateral stability of the trunk, and it suggested that this is the function which has been selected for in human evolution.     

Extra-lobal and complex dimorphic features in Middle Devonian palaeocopine ostracods

With respect to Middle Devonian ostracods from western Canada, special cases of palaeocopine extradomiciliar dimorphism are discussed, as in the opinion of many workers are unusual for younger hollinoideans and, in particular, primitiopsoideans. Although the general view that velar dimorphism is the main characteristic of Mid Palaeozoic Palaeocopina is basically not wrong, dimorphic histial structures, even though less conspicuous in aspect, have been recognised in some Mid-Devonian hollinoideans, specifically hollinids and ctenoloculinids. This is now also proven to be true of distinct hollinellids and, by the way, discrete primitiopsids, while distinguishing between narrow-based projections (ridges, flanges, spines) and broad-based protrusions (e.g. lobes). Whereas the former may occur in velar as well as histial situations, lobal features are especially found in the histial position. Special attention is paid to false primitiopsids, being (with some caution) grouped in the Hollinoidea (Family unknown). Essentially, three genera are new or redefined (former left under open nomenclature): Gen. aff. Abditoloculina: multilobate in aspect, lobal (histial) dimorphic; Gen. aff. Gravia: coalesced velar dimorphic; Bisphenella: histial dimorphic. With respect to the hold discussion about ostracod phylogeny, the updated standard classification scheme is given, as applied to Palaeozoic, non-myodocopine ostracods. Reduction of dimorphism in palaeocopines is considered to be an apomorphic character, lack of dimorphism assumed to indicate asexual reproduction. At the same time, a plea is made in favour of reviving Treatise revision.     

Automata simulation of the selection process

A complete simulation of the selection process can be constructed using a population of self-replicating finite-state automata. The entire population is challenged with a repeating sequence of inputs, and those individuals that are best able to recognize the input sequence are allowed to replicate most rapidly. Replication proceeds with imperfect fidelity, so that under the constraint of constant total population size, a quasispecies distribution of error copies is obtained. The operation of this simulation provides an essential representation of an evolving system. When the input sequence is altered, the structure of the existing population is destabilized, and a new quasispecies distribution emerges. The ability of the system to respond to changes in the input and the structure of the quasispecies distribution are shown to be critically dependent on the fidelity of replication.     

具有智能生物种群的演化:学习方式对群体演化的影响(英文)

在Penna model基础上引入智能因素,建立了具有学习能力的生物演化模型.考虑智能、经验和环境因素定义了个体的学习方式,讨论了学习方式及学习的知识类型对种群演化的影响.从所得结果看出个体只有充分利用环境,才能使种群规模和群体平均知识有明显的增加.然而随着对外界环境利用程度的加强,种群的平均智能却是在下降,这一点对于联系越来越紧密的人类来说真是值得深思的一个问题.     

Simulation exercises for environmental biology teaching

Simulation exercises are of particular relevance in the presentation of issues in environmental aspects of biology. Three examples, which require no special apparatus or materials, are described, each being presented in a different way and relating to a different aspect of the subject.

A series of prepared sheets lists basic parameters which influence the size of a population of herbivorous mammals, different combinations of factors and random events yielding a wide range of population changes in the course of a simulation during which the participants carry out simple arithmetical calculations of natality, mortality and changes in age-distribution of the population.

Pollution, arising from several industrial and agricultural sources, combines with fluctuation in flow rate to bring about changes in the biota of a river. The changes are illustrated by altering the positions of cards on a board; the events which generate the changes being brought about by drawing cards from a pack. Participants take turns to ‘sample’ the river or to bring about events. Alternatively, the board can be used by the teacher as a visual aid to demonstrate the ways in which changes may occur.

The survival of wildlife in the face of changing conditions in British farming practice is the subject of a competitive game intended to provoke discussion of the issues involved. Each player is provided with a small board representing a farm. This has to be managed with due regard for economic factors while the player attempts to manipulate habitats in order to increase the diversity of wildlife on his land.

All three simulations are intended to be used with senior classes in secondary education (16–18 age group) though they may be adapted for use with other groups.

A list of requirements for setting up each simulation is appended.     

Sperm ultrastructure and a new type of spermiogenesis in two species of Pimelodidae, with a comparative review of sperm ultrastructure in Siluriformes (Teleostei: Ostariophysi)

During spermiogenesis, the spermatids of the pimelodid species Pimelodus maculatus and Pseudoplatystoma fasciatum show a central flagellum development, no rotation of the nucleus, and no nuclear fossa formation, in contrast to all previously described spermatids of Teleostei. These characteristics are interpreted as belonging to a new type of spermiogenesis, named here type III, which is peculiar to the family Pimelodidae. In P. maculatus and P. fasciatum, spermatozoa possess a spherical head and no acrosome; their nucleus contains highly condensed, homogeneous chromatin with small electron-lucent areas; and a nuclear fossa is not present. The centriolar complex lies close to the nucleus. The midpiece is small, has no true cytoplasmic channel, and contains many elongate and interconnected vesicles. Several spherical to oblong mitochondria are located around the centriolar complex. The flagellum displays the classical axoneme (9+2) and no lateral fins. Only minor differences were observed among the pimelodid species and genera. Otherwise, spermiogenesis and spermatozoa in the two species of Pimelodidae studied exhibit many characteristics that are not found in other siluriform families, mainly the type III spermiogenesis.     

Structure and evolution of the stigmapophysis—A unique repose wing-coupling structure in Psocodea

The gain of foldable wings is regarded as one of the key innovations enabling the present-day diversity of neopteran insects. Wing folding allows compact housing of the wings and shields the insect body from damage. Wing-fixing systems have evolved in some insects, probably to increase the durability of the shielding function by the wings. Bark lice (Psocodea) are known to possess a unique wing-to-wing repose coupling system, but a detailed morphological and evolutionary study of this system is lacking. In this study, we examined this repose coupling structure by SEM in 32 species including representatives of all three suborders of bark lice (Trogiomorpha, Troctomorpha and Psocomorpha). We concluded that the repose wing-coupling apparatus independently evolved twice within Psocodea. In Trogiomorpha, the apparatus is located on the subcostal vein of the forewing and is composed of elongated rib-like structures. In Troctomorpha and Psocomorpha, in contrast, the repose coupling structure is located on the radius vein of the forewing and is formed by a swollen vein. These morphological and developmental differences in the repose coupling structures also provide phylogenetic information at different systematic levels.     

Serotonin immunoreactivity in the nervous system of the Pandora larva, the Prometheus larva, and the dwarf male of Symbion americanus (Cycliophora)

Cycliophora is a recently described phylum of enigmatic metazoans with a very complex life cycle that includes several sexual and asexual stages. Symbion pandora and Symbion americanus are the only two cycliophoran species hitherto described, of which morphological and genetic knowledge is still deficient to clarify the phylogenetic position of the phylum. Aiming to increase the database on the cycliophoran neural architecture, we investigated serotonin immunoreactivity in the free swimming Pandora larva, the Prometheus larva, and the adult dwarf male of S. americanus. In the larval forms, serotonin is mainly expressed in a ring-shaped pattern at the periphery of the antero-dorsal cerebral ganglion. Additionally, several serotonergic perikarya emerge from both sides of the cerebral ganglion. Thin neurites project anteriorly from the cerebral ganglion, while a pair of ventral longitudinal neurites emerges laterally and runs along the anterior-posterior body axis. Posteriorly, the ventral neurites fuse and extend as a posterior projection. In the dwarf male, serotonin is found mainly in the commissural neuropil of the large anterior cerebral ganglion. In addition, serotonin immunoreactivity is present in the most anterior region of the ventral neurites. Comparative analysis of spiralian nervous systems demonstrates that the neuroanatomy of the cycliophoran larval stages resembles much more the situation of adult rather than larval spiralians, which may be explained by secondary loss of larval structures and heterochronic shift of adult components into the nervous system of the Pandora and the Prometheus larva, respectively.