盾盘亚纲二种盾盘吸虫Aspidogaster conchicola和Lophotaspis orientalis神经系统结构差异的研究

采用乙酰胆碱组织化学定位方法,分别对盾盘亚纲两种吸虫Aspidogaster conchicola和Lophotaspis orientalis的神经系统进行染色观察.经比较,两种吸虫的腩神经节及神经联合的位置郁位于咽前部;由脑神经节向前发出的神经干最终会合于围口神经环;脑神经节向后发出3对神经干,其中后腹神经干最为粗大,它通过多对神经与腹吸盘相连.二者存在的差别在于:第一,体前神经干的分支数目及分布位置不同;第二,腹吸盘部神经分布形式不同;第三,Aspidogaster conchicola的两侧排泄管均有明显着色,并显示螺纹状结构.     

Comparative anatomy of the cheek muscles of Korean cobitid fishes (Ostariophysi: Cypriniformes), with the comments on their phylogenetic relationships

Cheek muscles of 16 species of all Korean cobitid species belong to six genera were examined and described in detail, with comments on their phylogenetic relationships made on the basis of characteristics of cheek muscles. Korean cobitids were divided into two groups, the Cobitis and Misgurnus groups, by five characters related to three cheek muscles (adductor mandibulae, preorbitalis, and retractor arcus palatine). The former group, comprising Cobitis, Iksookimia, Kichulchoia, Koreocobitis, and Niwaella, is defined by four apomorphies, and the latter, including Misgurnus, by a single apomorphy.     

Egg structure and outline of embryonic development of the basal mantodean, Metallyticus splendidus Westwood, 1835 (Insecta,Mantodea, Metallyticidae)

The egg structure and outline of the embryonic development of Metallyticus splendidus of one of the basal Mantodea representatives, Metallyticidae, were described in the present study. The results obtained were compared with those from the previous studies, to reconstruct and discuss the groundplan of Mantodea and Dictyoptera. In M. splendidus, the egg is spheroidal, it has a convex ventral side at the center in which numerous micropyles are grouped, and it possesses a conspicuous hatching line in its anterior half. These are the groundplan features of mantodean eggs and the “grouped micropyles in the ventral side of the egg” are regarded as an apomorphic groundplan feature of Dictyoptera. A small circular embryo is formed by a simple concentration of blastoderm cells, which then undergoes embryogenesis of the typical short germ band type. Blastokinesis is of the “non-reversion type” and the embryo keeps its original superficial position and original orientation throughout embryonic development. During the middle stages of development, the embryo undergoes rotation around the egg's anteroposterior axis. These features are a part of the groundplan of Mantodea. It is uncertain whether sharing of the “non-reversion type” of blastokinesis by Mantodea and blaberoidean Blattodea can be regarded as homology or homoplasy.     

A revision of Platybothrium Linton, 1890 (Tetraphyllidea: Onchobothriidae), with a phylogenetic analysis and comments on host-parasite associations

A revision of Platybothrium Linton, 1890 is presented, based on available type and voucher material, as well as extensive new collections from elasmobranchs belonging to the Carcharhinidae (requiem sharks) and Sphyrnidae (hammerhead sharks). All 10 nominal Platybothrium species are treated or redescribed herein. Four of these 10 nominal species, in addition to one former member of Dicranobothrium Euzet, 1953, are considered valid members of Platybothrium. Five new Platybothrium species are described: P. angelbahiense n. sp. ex Carcharhinus leucas, P. coshtaprum n. sp. ex C. plumbeus, P. jondoeorum n. sp. ex Negaprion acutidens and C. melanopterus, P. kirstenae n. sp. ex C. obscurus, and P. tantulum n. sp. ex Sphyrna lewini and S. zygaena. Sixty-three morphological characters were employed in cladistic analyses of nine Platybothrium species and five outgroup species. Coding and analysis strategies were varied to assess the effects of coding inapplicable characters as missing or as a separate character state, and of excluding characters for which data are missing in more than 10% of the taxa. The analysis in which inapplicable characters were coded as a separate character state and no characters were excluded produced the best-supported and most conservative estimate of the interrelationships of Platybothrium spp. Platybothrium appears to be a monophyletic assemblage, with the most basal species being P. spinulifera Southwell, 1912. The group of species possessing an accessory piece between the hooks forms a clade within the genus. Species lacking an accessory piece, which had previously been placed in Dicranobothrium Euzet, 1953, do not appear to be each other's closest relatives; thus, Dicranobothrium is considered a synonym of Platybothrium. An examination of host associations indicated that Platybothrium species are broadly distributed among, and entirely restricted to, carcharhinid and sphyrnid shark species. Most Platybothrium species exhibit oioxenous host-specificity, with all but two species each parasitising only a single host species. In several host species, multiple Platybothrium congeners parasitise the same host individual, a phenomenon not previously reported for Platybothrium.     

Form and function of the tongue in agamid lizards with comments on its phylogenetic significance

The morphology of the tongue of agamid lizards is reviewed and discussed in the context of its functional and phylogenetic significance. It is shown that in several features, including the development of the central musculature of the tongue into a ring muscle and the presence of a genioglossus internus muscle in adults, the tongue in most agamids is derived relative to that in other squamates. In some features, such as the vertical connective tissue septa, agamids share primitive features with Sphenodon. Some conditions found in agamids are also found in anoline iguanids. Two genera, Uromastyx and Leiolepis, differ significantly from other agamids in intrinsic tongue musculature. The functional significance of the unique tongue morphology is that agamids utilize a different mechanism of tongue protrusion from that of other lizards. This mechanism involves the production of force against the lingual process, leading to an anterior slide of the tongue, and is detailed in this paper. Finally, I discuss the mechanical basis for the transformation series of tongue protrusion mechanisms from agamids to chamaeleonids. It is suggested that the mechanism of tongue protrusion in chamaeleonids is not unique, but is a highly derived state of the condition found in agamids.     

Egg development, hatching and early life-history of Dissonus manteri (Copepoda), parasitic on the gills of coral trout, Plectropomus leopardus

The early life-history of Dissonus manteri differs markedly from that of Caligidae and from that of its congener Dissonus nudiventris. The uniseriate egg strings are of typical caligid form, but the stage hatching from the egg is a preecdysis nauplius which moults immediately to the copepodid. The empty naupliar cuticle remains tethered to the egg string by a pair of posterior threads which attach to the internal surface of the egg membrane. The duration of egg development is 112 h and the mean duration of hatching is 5.2 h at 25 degrees C. Aeration and water movement are important for successful hatching. Under these conditions, hatching success is 94.8%, but decreases to 48.4% in static water with no aeration. Mean survival time of the copepodid in the absence of a host is 41.4 h at 25 degrees C. The reduction of early free-living stages in the life-cycle and the high survival rate from egg to copepodid could be important in future coral trout aquaculture, since the potential for re-infection by this parasite is very high.     

Comparative body wall musculature and muscle fibre ultrastructure in branchiobdellidans (Annelida: Clitellata), and their phylogenetic significance

The body wall muscles in five species of branchiobdellidans are all arranged in the oligochaete pattern and the muscle fibres are obliquely striated. The structure of the circular muscle fibres do vary to some degree. The longitudinal muscle fibres in Ankyrodrilus legaeus, Branchiobdella kozarovi, and Xironogiton instabilis all are round circomyarian and thus double-obliquely striated. These species represent three of the four genera composing the family Branchiobdellidae. Although Bdellodrilus illuminatus and Cambarincola fallax, from the families Bdellodrilidae and Cambarincolidae, respectively, also possess a few round circomyarian fibres, most are polyplatymyarian comparable to single-obliquely striated fibres. A similar division of branchiobdellidan families is obtained based on the number of anterior nephridial pores. The muscular structure in the branchiobdellidans shows both similarities and differences with the leeches and the lumbriculid oligochaetes. One phylogenetic explanation for this is that the branchiobdellidans separated from the common clitellate ancestor before the oligochaetes and leeches became recognizable taxa.     

The ultrastructure of the spermatozoa of Epipedobates flavopictus (Amphibia,Anura, Dendrobatidae), with comments on its evolutionary significance

We describe, for the first time, the spermatozoon ultrastructure of a dendrobatid frog, Epipedobates flavopictus. Mature spermatozoa of E. flavopictus are filiform, with a moderately curved head and a proportionally short tail. The acrosomal vesicle is a conical structure that covers the nucleus for a considerable distance. A homogeneous subacrosomal cone lies between the acrosome vesicle and the nucleus. The nucleus contains a nuclear space at its anterior end, and electron-lucent spaces and inclusions. No perforatorium is present. In the midpiece, the proximal centriole is housed inside a deep nuclear fossa. Mitochondria are scattered around the posterior end of the nucleus and inside the undulating membrane in the anterior portion of the tail. In transverse section the tail is formed by an U-shaped axial fiber connected to the axoneme through an axial sheath, which supports the undulating membrane. The juxta-axonemal fiber is absent. The spermatozoon of E. flavopictus has several characteristics not observed before in any anurans, such as a curved axial fiber, absence of a juxta-axonemal fiber, and presence of mitochondria in the typical undulating membrane. Our results endorse the view that, in anurans, the conical perforatorium and subacrosomal cone are homologous and that Dendrobatidae should be grouped within Bufonoidea rather than Ranoidea.     

Surface-mound formation by the Tuco-tuco, Ctenomys fulvus (Rodentia: Ctenomyidae), with comments on earth-pushing in other fossorial mammals

Surface-mound formation by Ctenomys fulvus (and evidently most Ctenomyidae, an autochthonous South American family) differs from most other fossorial mammals in that soil is transported to the surface by kicking with the hind feet (a habit shared with most Bathyergidae. the African mole-rats). The greatly enlarged hind feet of Ctenomys are the largest for any terrestrial fossorial group. The eyes of Ctenomys , also different from many mole types, are large and appear better protected by hind foot soil-pushing. The manner in which the stocky tail of Ctenomys supports the body above the substratum while kicking synchronously with the hind feet is unusual for any mammal.
The body facing forward while pushing soil, the position favoured by most mole-types, allows for the scanning of the surface for predators and defence through the use of teeth, claws and direct vocalizing, while hind foot soil-pushing conserves energy by negating the need to turn around in the tunnel after digging, and again after depositing soil on the surface. Studies are required to determine the efficiency of various predators on the capture of mole-types as soil is being pushed on to the surface, perhaps the most significant selective pressure on the manner of pushing soil.     

Palaeopedogenic features and their palaeoclimatological significance for the nevremont formation (Lower Givetian), the Northern Ardennes,Belgium

The lower member of the Nèvremont Formation is characterized by the frequent occurrence of pedogenic features, which suggest intermittent exposure of the fluvial depositional environment.The evidence for pedogenesis comprises horizons of calcite glaebules and nodular calcrete, haematite segregation, resulting in pronounced colour mottling, and the formation of palaeosolic root-horizons with root tubes, cutanic features, burrows and striotubules.Based upon the presence of these features, it is suggested that the climate was semiarid. The source area of the quartz-rich parent clastic sediment was presumably subjected to intensive chemical weathering, resulting in mature quartzose sediments, with illite and kaolinite as dominant clay minerals.     

An investigation of the cranial evolution of Asian pitvipers (Serpentes: Crotalinae), with comments on the phylogenetic position of Peltopelor macrolepis

Guo, P., Jadin, R.C., Malhotra, A. and Li, C. 2009. An investigation of the cranial evolution of Asian pitvipers (Serpentes: Crotalinae), with comments on the phylogenetic position of Peltopelor macrolepis—Acta Zoologica (Stockholm) 91 : 402–407. We investigated the evolution of 12 cranial characters of 31 species of Asian pitvipers by examining the character state changes on a consensus tree modified from broadly consistent molecular results. We found that these characters appear stable with only one intraspecific polymorphism. Nine of the 12 characters form useful synapomorphies, whereas three are ambiguous and evolutionarily plastic. Clades that are supported with numerous apomorphies are the Trimeresurus group [consisting of the recently defined genera Trimeresurus sensu Malhotra and Thorpe (2004) , Parias, Popeia, Viridovipera, Himalayophis, and Cryptelytrops] and the genera Protobothrops, Parias, and Viridovipera. Two species previously considered as congeners but now known to be distantly related, Ovophis monticola and ‘Ovophis’okinavensis, have nearly identical character states, demonstrating substantial convergence in cranial characters. Finally, we attempt to infer the phylogenetic position of Peltopelor macrolepis by comparing its cranial features with that of other pitvipers.     

Tibial combs in the Cydnidae (Hemiptera: Heteroptera) and their functional, taxonomic and phylogenetic significance

Tibial combs in representatives of the family Cydnidae are described in detail for the first time. The structure was studied in 98 species of 58 genera representing all the subfamilies, among them 16 species were investigated using scanning electron microscopic (SEM) techniques. In addition, Parastrachia japonensis (Scott, 1880) of the family Parastrachiidae, and two species of Dismegistus Amyot and Serville, 1843 (a genus of uncertain systematic position within Pentatomoidea) have also been studied. Morphological terminology is proposed for all the structures connected with tibial combs and the term 'the tibial comb complex' is suggested; its functional, taxonomic and phylogenetic significance is also discussed. The genera of Cydnidae can be classified into two groups depending on differences in the tibial comb complex, when it is present; moreover, its absence in the tribe Scaptocorini (Cephalocteinae) is demonstrated for the first time and is regarded as an autapomorphy of this tribe. Data on the occurrence of tibial combs in other families of true bugs (Hemiptera: Heteroptera) are also briefly reviewed, and an anagenetic trend in their evolution in terrestrial Heteroptera is hypothesized. The presence of tibial combs on all legs is regarded as the most plesiomorphic state.     

Dactylogyrids (Monogenea: Dactylogyridea) with unusual number of the anchors, their origin and phylogenetic significance. Original data

The haptors Dactylogyrus spp., Anacanthorus sp., Trianchoratus sp. and Schilbetrematoides pseudodactylogyrus are investigated. On the base of the morphology, transfer of the domus, etc. a homology of the hooks in dactylogyrids (s. s.) and the pin-like structures (4 "A") in the haptor of Anacanthorinae and Dactylogyridae sensu Bychowsky et Nagibina, 1978 is demonstrated. The vestiges of the anchors in the haptor of dactylogyrids (s. l.), according to morphological data, correspond to the point of anchor formed during the ontogenesis. In S. pseudodactylogyrus the pins are redescribed as typical vestiges of the anchors.     

Revision of the enigmatic Australasian genus Miropotes Nixon (Hymenoptera: Braconidae: Microgastrinae), with comments on the phylogenetic importance of the female ovipositor system

Abstract. The endemic Australasian microgastrine genus Miropotes Nixon, previously known from two species, M. creon Nixon from Tasmania and M. petiolaris (Szépligeti) from N.S.W., is revised. A further eight species are described as new (M. burringbaris, M. boothis, M. chookolis, M. goobitis, M. kilkulunis, M. cadgeis, M. katois and M. thuraris) , two of which represent the first record of the genus outside continental Australia (viz New Guinea, New Hebrides and New Caledonia). A key to species is presented along with information on the first host record for the genus. Relationships between Miropotes and other microgastrine genera are discussed, particularly in reference to the structure of the ovipositor and hypopygium, which have bearing on the current tribal classification of the subfamily.