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1.
2.
A new species, Melanostigma olgae sp. n., is described from the Southern Ocean. The type series was obtained along the South Sandwich Islands (Scotia Sea, Western Antarctic) at the depths of 800?850 m. The new species differs from the other representatives of Melanostigma genus by the original combination of the features of the seismosensory system, axial skeleton, and coloration. The homologization of the structural elements (senses) of the head canals of the lateral line has been done for the first time for the Melanostigma. Morphology of M. olgae allows considering this species as the most evolutionary advanced within the representatives of this genus inhabiting the Southern Ocean. The key of the Antarctic species of the genus Melanostigma is provided.  相似文献   

3.
Structure of the seismosensory system in Oncopterus darwinii is studied. Specific traits are revealed, along with the general similarity with previously investigated representatives of the order Pleuronectiformes. Presence of some plesiomorphic features characterizes the structure of the seismosensory system of O. darwinii as the generalized one.  相似文献   

4.
A detailed morphological comparison is made of the North Pacific specimen of Thalassobathia pelagica with fish from the North Atlantic (the type locality). The Pacific specimen is recognized as conspecific with Atlantic ones. Insignificant differences are considered as age or individual variation. The structure of the seismosensory system of T. pelagica and morphology of this species are described in more detail. The probable distribution of T. pelagica is discussed. A wide tropical area of this species is assumed and a possibility of its presence in all three oceans. The captures of T. pelagica in high latitudes may depend on its transportation with warm currents.  相似文献   

5.
The underyearlings of roach, Rutilus rutilus, displayed a bilateral asymmetry of C-bend—the initial stage of escape behavior. Most individuals exhibited a significant bias to turn leftward or rightward after being stimulated by electrical current. This individual asymmetry was consistent when the same fish were retested ten days later. A significant correlation was revealed between the behavioral asymmetry and the bilateral asymmetry of surface area of frontal (positive correlation) and parietal (negative correlation) cranial bones. No significant correlation was found with the bilateral asymmetry of other morphological characteristics: numbers of pores of the seismosensory canals (praeopercular-mandibular, supraorbital, and supratemporal) in flat cranial bones (dental, praeopercular, frontal, and parietal numbers of lateral line pores, and numbers of rays in pectoral and ventral fins.  相似文献   

6.
The study of the cell wall structure was performed for ten species of Euastrum: E. ansatum (Ehrenb.) Ralfs, E. bidentatum Näg., E. binale (Turp.) Ehrenb. ex Ralfs, E. dubium Näg., E. elegans (Bréb.) Kütz. ex Ralfs, E. germanicum (Schmidle) W. Krieger, E. oblongum (Grev.) Ralfs ex Ralfs, E. pectinatum Bréb. ex Bréb. in Ralfs, E. validum West et G.S.West, E. verrucosum (Ehrenb.) ex Ralfs. The investigation of the cell wall ultrastructure has established for the first time that the pore canal in 6 of 10 species always has a coiled form to some degree. Three species (E. germanicum, E. pectinatum, and E. verrucosum) have both coiled and straight canals, and E. ansatum has only straight ones. A new type of pores (P7), typical only for representatives of the genus Euastrum, was also noted. In addition, a simple and effective method of preparing desmidium algal cells for investigation with transmission electron microscope has been developed.  相似文献   

7.
The Southern festoon, Zerynthia polyxena, is a south-European butterfly listed in Annex IV of the Habitats Directive (92/43/EEC). Populations from most of the Italian territory have been recently recognized as belonging to a separate species, endemic to Italy: Zerynthia cassandra. In the province of Bologna (northern Italy), Z. cassandra is quite common. The territory of the province is densely inhabited and modified by man. Semi-natural environments are found almost exclusively in the hills, while the plain is almost entirely built-upon or cultivated. This study was based on data collected in the field in the province of Bologna, and aimed to investigate some biological and ecological aspects of Z. cassandra, with the purpose of identifying the factors that favour its presence and the most relevant issues for its conservation. In the area of study, the hostplant of Z. cassandra is Aristolochia rotunda, which is common in the plain, along the edges of drainage canals, where it supports a large Z. cassandra population. In the hills, A. rotunda is scarcer, and Z. cassandra is present in small separated nodes. Human activities such as mowing and canal maintenance are potentially damaging to Z. cassandra, particularly if carried out when eggs and larvae are present. However, if correctly timed and executed, such maintenance can preserve grassy areas that would otherwise be colonized by bushes and trees, and in which A. rotunda finds a suitable environment. Some level of disturbance can be beneficial for Z. cassandra habitats, favouring the species’ survival in the long term.  相似文献   

8.
A new species Melanostigma kharini sp. n. is described from the underwater Ridge of Hercules (Pacific-Antarctic Rise). The specimens of the new species were collected in the marine expeditions of the Pacific Scientific Research Institute of Fishery and Oceanography (TINRO) (1977?1978) on the Southern Bank at depths between 240 and 780 m. The new species differs from the other species of the genus in an original combination of the characters, in particular, in the structure of the lateral line canals on the head, axial skeleton, and coloration. Vertebral asymmetry and the features of rational (purposive) development of the seismosensory system on the head of Melanostigma are described in detail.  相似文献   

9.
The taxonomic relations of two flatfish genera, Pseudopleuronectes and Liopsetta were examined for the species Ps. yokohamae, L. obscura and L. pinnifasciata with the use of morphometry and lateral line system structure analysis. Ps. yokohamae and L. obscura were found to be very similar in the majority of plastic and meristic characters and in the arrangement of the lateral line sensory canals on the head. Our findings confirmed the recent suggestions of a close relationship between Ps. yokohamae and L. obscura and provided a solid argument for the transfer of L. obscura from the genus Liopsetta to the genus Pseudopleuronectes.  相似文献   

10.
The lateral line system and its innervation were examined in a generalized perch-like species, Lateolabrax japonicus (Percoidei incertae sedis), and compared with those in two species of Apogonidae (Fowleria variegata in Apogonichthyini and Ostorhinchus doederleini in Ostorhinchini) characterized by proliferated superficial neuromasts (SNs) on the head, trunk lateral line scales and caudal fin. The total number of SNs differed greatly between the two groups, being 271 in the former, and 2,403 and 4,088 in the latter. The mandibular ramus (MDR) was extensively ramified in the head of the apogonids, with three additional branches that were absent in L. japonicus, innervating 1,117 SNs in F. variegata and 1,928 in O. doederleini. In the apogonids, the additional anterodorsal branch of the MDR coursed parallel to the buccal ramus anteriorly (on the interorbital space) and to the supratemporal ramus posteriorly (on the temporal region). The two parallel portions supplied numerous SN rows forming a characteristic crosshatch pattern, the branch and two rami distributing to transverse and longitudinal rows, respectively. In the two groups, the trunk lateral line scales each housed a canal neuromast (CN; partly replaced by an SN in F. variegata). In addition, one to four (in L. japonicus) and three to 55 (in the apogonids) SNs occurred on each lateral line scale, the pattern of SN innervation being identical in having two types of branches; one innervated a CN and SNs, and the other SN(s) only. The latter type extended only to a limited number of scales in L. japonicus, but to nearly all or all scales in the apogonids. Compared with F. variegata, branches of the respective types were more finely ramified with greater number of SNs in O. doederleini.  相似文献   

11.
A new species, Tryssogobius fisunovi sp. n., is described from the depth of 73 m in the region of the Anambas Islands (Indonesia), South China Sea. Based on the presence of the preopercular and orbito-scapular canals, the species is similar to T. porosus, but it differs from the latter species in coloration, location of the mental row of genipores f, separated pelvic fins, and other characters. The problems of the systematics of the genera Tryssogobius and Obliquogobius are discussed.  相似文献   

12.
Two unusual Middle Ordovician crinoid genera from the St. Petersburg Region, Pentamerocrinus Jaekel, 1918 and Grammocrinus Eichwald, 1860, are redescribed. A new species, Pentamerocrinus kosovi sp. nov., is described based on new material and the cup structure in the type species Grammocrinus lineatus, which has previously been known only from stem fragments, is reconstructed. The system of ridges and canals on the internal surface of the cup plates in both genera is described, allowing the reconstruction of the aboral nervous system. It is in general similar to extant crinoids, but the two Ordovician genera differ considerably in structural details. In Pentamerocrinus, ten nerve cords diverge interradially from the ganglionated nerve ring at the cup base and soon are fused in pairs inside the rays. In Grammocrinus, a similar nerve ring also gives rise to ten cords, but they are inside the rays and become fused in the interrays. This distinction in morphology of the nervous systems is correlated with the interradial arrangement of the axial canal angles of the stem in the first case and radial in the second. Therefore, despite general similarity in the structure and arrangement of calyceal plates, the genus Grammocrinus is assigned to the disparid crinoid family Iocrinidae, while the monotypic family Pentamerocrinidae Jaekel, 1918 is regarded as a fam. inc. sed. of inadunate crinoids.  相似文献   

13.
A new species, Gobiopsis uranophilus sp. n., is described off the Anambas Islands, South China Sea, from a depth of 73 m. The species is similar to the deepwater Japanese species G. namnas, but it differs in the dorsal orientation of the eyes, total absence of pores of the seismosensory system on the head, number of fin rays, and other characters. The similar patterns of the two species (presence of scales on the sides of the head, absence of the barbel-shaped appendages on the head, and large scales on the body), most likely, are connected with their adaptation to deepwater habitats.  相似文献   

14.
Based on light and scanning electron microscopical studies, a new nematode parasite, Lobocapillaria austropacifica n. sp. (Capillariidae), is described from the gall-bladder of the marine fish (obtuse barracuda) Sphyraena obtusata Cuvier (Perciformes: Sphyraenidae) from off the eastern Pacific coast of Australia, for which a new genus Lobocapillaria n. g. is established. This new genus is mainly characterised by a single row of stichocytes, the presence of two large, conspicuously elongated lateral caudal lobes and a pair of subventral papillae at their base in males, a flat spicule distended laterally towards its proximal end and provided with superficial rough transverse grooves, a spicular canal and a very long, aspinose spicular sheath with a conspicuous expansion near its proximal end when evaginated. Capillaria sphyraeni Parukhin, 1971 is transferred to Lobocapillaria as L. sphyreni (Parukhin, 1971) n. comb. A key to capillariid genera containing species parasitic in fishes is provided.  相似文献   

15.
The functional role of burst firing (i.e. the firing of packets of action potentials followed by quiescence) in sensory processing is still under debate. Should bursts be considered as unitary events that signal the presence of a particular feature in the sensory environment or is information about stimulus attributes contained within their temporal structure? We compared the coding of stimulus attributes by bursts in vivo and in vitro of electrosensory pyramidal neurons in weakly electric fish by computing correlations between burst and stimulus attributes. Our results show that, while these correlations were strong in magnitude and significant in vitro, they were actually much weaker in magnitude if at all significant in vivo. We used a mathematical model of pyramidal neuron activity in vivo and showed that such a model could reproduce the correlations seen in vitro, thereby suggesting that differences in burst coding were not due to differences in bursting seen in vivo and in vitro. We next tested whether variability in the baseline (i.e. without stimulation) activity of ELL pyramidal neurons could account for these differences. To do so, we injected noise into our model whose intensity was calibrated to mimic baseline activity variability as quantified by the coefficient of variation. We found that this noise caused significant decreases in the magnitude of correlations between burst and stimulus attributes and could account for differences between in vitro and in vivo conditions. We then tested this prediction experimentally by directly injecting noise in vitro through the recording electrode. Our results show that this caused a lowering in magnitude of the correlations between burst and stimulus attributes in vitro and gave rise to values that were quantitatively similar to those seen under in vivo conditions. While it is expected that noise in the form of baseline activity variability will lower correlations between burst and stimulus attributes, our results show that such variability can account for differences seen in vivo. Thus, the high variability seen under in vivo conditions has profound consequences on the coding of information by bursts in ELL pyramidal neurons. In particular, our results support the viewpoint that bursts serve as a detector of particular stimulus features but do not carry detailed information about such features in their structure.  相似文献   

16.
Dystonia musculorum (dt) mice show sensory neurodegeneration and movement disorder, such as dystonia and cerebellar ataxia. The causative gene Dystonin (Dst) encodes a cytoskeleton linker protein. Although sensory neurodegeneration has been well studied, glial cell responses in the central nervous system (CNS) are poorly understood. Here, we investigated cell proliferation in the CNS of Dst Gt homozygous mice using newly generated in situ hybridization (ISH) probes—Ki-67 and proliferating cell nuclear antigen (PCNA) probes—both of which effectively detect proliferating cells. We found that Ki-67-positive cells were significantly decreased in the corpus callosum and thalamus of dt brain at postnatal day 21 (P21). There is a similar but not significant tendency at postnatal day 14 (P14) in the dt brain. We also confirmed the reduced proliferation by PCNA ISH and Ki-67 immunohistochemistry. Double staining with cell-type-specific markers revealed that proliferating cells are oligodendrocyte progenitor cells (OPCs) in both wild-type and dt brain. We also observed a reduced number of Olig2-positive cells in the corpus callosum of Dst Gt homozygous mice at P21, indicating that reduced proliferation resulted in a reduced number of OPCs. Our data indicate that OPCs proliferation is reduced in the dt mouse brain at the postnatal stage and that it subsequently results in the reduced number of OPCs.  相似文献   

17.
Aquatic vegetation of Hydrochari-Lemnetea and Potametea classes in the Danube-Tisza-Danube hydrosystem (Hs DTD) was studied in 2009–2012, by applying the standard Braun-Blanquet method. The canal network vegetation comprises 14 associations, with Trapetum natantis and Ceratophylletum demersi being the most widely distributed. Hs DTD is also a habitat for several important endangered species, which serve as edificators of the following phytocenoses: Nymphaeetum albae, Nymphaeetum albo-luteae, Nymphoidetum peltatae, Trapetum natantis, Lemno-Spirodeletum, Salvinio-Spirodeletum polyrrhizae, Lemno-Utricularietum vulgaris, Potametum nodosi, Myriophyllo-Potametum and Najadetum marinae. In the studied vegetation, we also found an invasive phytocenosis Elodeetum canadensis that did not have an expanding tendency, and Ceratophyllo demersi-Vallisnerietum spiralis that had this tendency, which made monitoring its stands necessary. Physico-chemical analyses of water, conducted at localities in which the studied phytocenoses thrive, revealed that the development and distribution of most phytocenoses is closely linked with specific habitat conditions. Among the studied parameters, the most significant for the phytocenoses differentiation were: pH, alkalinity, COD-MnO4, BOD5, NO 3 ? , NO 2 ? , PO 4 3? and the concentration of total phosphorus.  相似文献   

18.
The yeasts of the Malassezia genus are opportunistic microorganisms and can cause human and animal infections. They are commonly isolated from the skin and auricular canal of mammalians, mainly dogs and cats. The present study was aimed to isolate Malassezia spp. from the acoustic meatus of bats (Molossus molossus) in the Montenegro region, “Rondônia”, Brazil. From a total of 30 bats studied Malassezia spp. were isolated in 24 (80%) animals, the breakdown by species being as follows (one Malassezia sp. per bat, N = 24): 15 (62.5%) M. pachydermatis, 5 (20.8%) M. furfur, 3 (12.5%) M. globosa and 1 (4.2%) M. sympodialis. This study establishes a new host and anatomic place for Malassezia spp., as it presents the first report ever of the isolation of this genus of yeasts in the acoustic meatus of bats.  相似文献   

19.
The leading factor responsible for the evolution of Philoliche rondani mouthparts, as well as those of the other long-proboscid Pangoniinae, appears to be adaptation to the intake of nectar from concealed sources (flowers with elongated floral tube). Adaptations to blood-sucking, inherent only in females, have morphogenetic and behavioral aspects. Philoliche rondani males, as compared to males of Tabanus-like species, have better developed clypeus, labrum, and labium. The presence of a long proboscis has led to transformation of the labial musculature and complication of the food canal structure. During the intake of nectar, the distalmost portion of this canal is formed only by the labium. The lateral labial folds form a peculiar closing apparatus. The cibarial and pharyngeal pumps of Philoliche rondani are similar to those of other tabanids investigated.  相似文献   

20.
Dermacentor nitens tick is commonly found in the equine auditory canal, where it causes economic losses due to its direct damage, causing blood spoliation, stress, transmission of pathogens, and predisposition to myasis and secondary bacterial infection in its hosts. In this study we evaluated the effect of ethanolic extracts of Cerrado plants on biological parameters of engorged females of D. nitens. Ethanolic extracts were prepared from the leaves of Schinopsis brasiliensis, Piptadenia viridiflora, Ximenia americana, and Serjania lethalis at 25–150 mg mL?1. Groups of 10 engorged adult females were treated with these extracts and compared with a control containing distilled water and another control with organophosphate, using five replicates for each group. Compared with the control with water, S. lethalis and X. americana extracts at 100 and 150 mg mL?1 significantly inhibited the posture ability. Differently, extracts of S. brasiliensis and P. viridiflora were the most effective in inhibiting larval hatching. Extracts of X. americana and P. viridiflora showed effective inhibition of reproductive parameters of the tick, presenting dose-dependent effect with IC90 78.86 and 78.94 mg mL?1, respectively. Theses effective extracts contained low condensed tannin levels and their HPLC chromatograms revealed the presence of flavonoids. The efficacies of P. viridiflora and X. americana extracts were higher than 90% indicating that these extracts are promising as alternative agents for D. nitens control.  相似文献   

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