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1.
Male Orthoptera singing from exposed perches are at risk from acoustically- and visually-hunting predators. The defensive reactions of armored ground crickets (Acanthoplus speiseri) include falling silent, dropping from their perch, alarm stridulation and autohaemorrhaging. Male and female ground crickets show different reactivity (i.e. the number or intensity of defense tactics used) to predation, depending on level of exposure: calling males were more reactive when approached during daylight, compared with in the dark. During daylight, calling males were more reactive than silent, cryptic, males and females. The level of response presumably reflected the riskiness of the individual’s behavior and situation at that time. Plasticity of response to predation allows individuals to balance risky behavior (i.e. acoustic signaling from exposed perches) by being more reactive to potential threats.  相似文献   

2.
Males of the closely related African tettigoniids Acanthoplus discoidales and Acanthoplus longipes produce a long-lasting calling song and a short disturbance sound. The temporal patterns of the sounds were analysed in respect to species differences and song type differences. The calling songs of both species consist of impulses which are separated into verses of two syllables, with fewer impulses in the first syllable. A. longipes produces more impulses in each syllable than A. discoidales and has longer verse durations, verse intervals and syllable intervals. Also, the disturbance sounds, produced after mechanical stimulation, contain distinct verses of impulses. The disturbance sound of A. longipes has a higher number of impulses per verse than that of A. discoidales. The frequency spectra of the songs in both species have similar peak frequencies (around 12.5 kHz) and both species have their greatest hearing sensitivity in the range between 5 and 10 kHz. Females of A. longipes perform phonotaxis only to songs with a species-specific temporal pattern. By contrast, females of A. discoidales react positively to calling songs of both species.  相似文献   

3.
Retrotapes andrillorum sp. nov., Hiatella cf. arctica (Linnaeus, 1767), ?Yoldia sp. (internal mould) and six taxa of Pectinidae are reported from the Burdigalian section of the ANDRILL 2A core, drilled in McMurdo Sound, Ross Sea. The pectinids are Adamussium cf. jonkersi Quaglio et al., 2010, Antarctipecten gen. nov. alanbeui (Jonkers, 2003), Austrochlamys forticosta sp. nov., Austrochlamys cf. marisrossensis Jonkers, 2003, Ruthipecten gen. nov., sp. nov. (not named) and a fragmentary specimen representing an unnamed genus and species. In a revision of Antarctic Pectinidae, Austrochlamys Jonkers, 2003, Ruthipecten gen. nov. (proposed for Chlamys (Zygochlamys) tuftsensis Turner, 1967, reported only from Wright Valley and the Vestfold Hills, not present in ANDRILL 2A), Leoclunipecten gen. nov. (proposed for Austrochlamys gazdzickii Jonkers, 2003, reported only from Oligocene rocks of King George Island, not present in ANDRILL 2A) and the unnamed genus in ANDRILL 2A are assigned to subfamily Chlamydinae, tribe Chlamydini, whereas Adamussium Thiele, 1934 and Antarctipecten gen. nov. are assigned to subfamily Palliolinae, tribe Adamussiini. The diverse Pectinidae in ANDRILL 2A suggest sea temperatures roughly 5°C warmer than at present in the Ross Sea during Early Miocene time.  相似文献   

4.
The morphology, biology and geographic distribution of Hypsibius zetlandicus (Murray 1907) are considered. Scanning electron microscopy (SEM) and/or light microscopy (LM) analyses have been carried out on H. zetlandicus and the type species of Hypsibius: Hypsibius dujardini (Doyère 1840), with particular emphasis on the buccal–pharyngeal apparatuses. Some unusual characteristics of this apparatus in H. zetlandicus lead us to the erection of the new genus Borealibius, to which H. zetlandicus (Borealibius zetlandicus comb. n.) is transferred. In the light of new discoveries of this species from polar, sub-polar and alpine regions, and based on the available bibliographic references, we hypothesize a boreo–alpine distribution for this species. The presence of traits that are unusual and rare (in other tardigrade species) have been observed whilst analyzing the reproductive biology and ecology of B. zetlandicus (i.e., the presence of hermaphroditism, parental care and the colonization of very different substrates).  相似文献   

5.
报道了中国兰科(Orchidaceae)隔距兰属(Cleisostoma Blume)一新记录种:角唇隔距兰(C.tricornutum Averyanov)。该种与C.crochetii(Guillaumin)Garay、C.parishii(J.D.Hooker)Garay相近,因其有不分枝的线状花粉团柄、球状的花粉团块和一个先端短喙状的半球形药帽而与C.crochetii(Guillaumin)Garay相区别;因其有松散、罕分枝的花序,长角状的唇瓣侧裂片而与C.parishii(J.D.Hooker)Garay相区别。提供了新记录种的形态描述及图片。  相似文献   

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8.
Herein, the results of the first study of the volatile and alkane profiles of Cephalaria ambrosioides Roem. & Schult . (Caprifoliaceae, subfamily Dipsacaceae) were reported. The GC‐FID and GC/MS analyses of the essential oils hydrodistilled from leaves and stems (CA1) and flowers (CA2) of C. ambrosioides allowed the identification of 284 different components. The main compounds of the studied oil samples were palmitic acid (24.3 and 32.5% for CA1 and CA2, resp.), hexahydrofarnesyl acetone (1.4 and 10.8% for CA1 and CA2, resp.), (Z)‐hex‐3‐en‐1‐ol (7.0 and <0.1% for CA1 and CA2, resp.), and linoleic acid (1.9 and 6.5% for CA1 and CA2, resp.). Essential‐oil compositional data of selected plant species belonging to the Dipsacaceae (15) and Morinaceae (2) subfamilies were used to resolve taxonomical ambiguities regarding the genus Cephalaria and its infrageneric relations, especially concerning the subfamily Morinaceae (formerly a genus within Dipsacaceae). The results of multivariate statistical analyses (25 different essential‐oil samples) supported the exclusion of Morina species from the Dipsacaceae subfamily. The relative abundances of alkanes from n‐, iso‐, and anteiso‐series followed a (distorted) Gaussian‐like distribution and suggested that the biosyntheses of n‐ and branched alkanes in C. ambrosioides are possibly not controlled by the same elongase. Also, the obtained results suggested that there was a difference in the biosynthesis/accumulation of alkanes in the vegetative and reproductive parts of C. ambrosioides.  相似文献   

9.
The colonial and multicellular members of the Volvocales can be arranged in order of increasing size and complexity as the “volvocine series.” This series is often assumed to reflect an evolutionary progression. The flagellar apparatuses of previously examined algae are not consistent with a simple lineage. The flagellar apparatuses of Astrephomene gubernaculifera Pocock, Gonium pectorale Müller, Platydorina caudata Kofoid, Volvox rousseletii G. S. West, and V. carteri f. weismannia (Powers) Iyengar differ from one another, and there is no apparent progression inflagellar apparatus features from the simple to complex colonial forms. We examined the flagellar apparatuses of Volvulina steinii Playfair, Eudorina elegans Ehr., and Pleodorina illinoisensis Kofoid and found them to be similar to one another. The basal bodies are connected by a distal fiber that is offset to the anti side of the cell. Two microtubular rootlets originate on the inside of the basal bodies and extend toward the syn side. The other two rootlets are oriented perpendicular to the first two and are anti-parallel to each other. A coarsely striated component underlies the four-membered rootlets and extends to the basal bodies. A proximal fiber complex connects the two basal bodies. This complex consists of a branched striated component on the cis side of each basal body. One part extends toward the anti side of the cell, while the other extends into a fibrous component that runs between basal bodies. An additional structure extends in the anti direction from the trans side of each basal body. A fibrous component extends past one basal body in all four species. This component goes past the trans basal body in Volvulina steinii and the cis basal body in E. elegans and P. illinoisensis. The flagellar apparatuses of these organisms are similar to those of G. pectorale and Volvox carteri but different from the other colonial volvocalean algae examined. The algae examined in this study plus G. pectorale and V. carteri probably share a common evolutionary history that postdates the transition from the unicellular to colonial habit. Such a shared evolutionary history is a requirement of the volvocine hypothesis. However, we have not observed progressive changes in the flagellar apparatus correlated with increasing cell number, differentiation, and sexual specialization. Thus, it is possible, but not certain, that G. pectorale, Volvulina steinii, E. elegans, P. illinoisensis, and Volvox carteri may form part of a volvocine lineage.  相似文献   

10.
ABSTRACT. A membranous closing apparatus shuts the lorica opening in disturbed tintinnids of six genera belonging to four families. The homology of the apparatuses is investigated, using data from the literature and Mediterranean tintinnids studied in vivo and by scanning electron microscopy. Morphological and functional similarities indicate that the foldable closing apparatus is not only a synapomorphy of the genera Codonella (Codonellidae) and Dictyocysta (Dictyocystidae), as suggested 80 years ago, but also of Codonaria (Codonellidae) and Codonellopsis (Codonellopsidae). In Codonaria, Codonella, and Dictyocysta, the apparatuses merge posteriorly into membranous lorica sacs, which probably represent homologous structures. The diagnoses of these genera are improved according to the new findings. The close relationship of Codonella, Codonellopsis, and Dictyocysta is also inferred from small subunit rRNA phylogenies and the ultrastructure of the capsules. It contradicts the current lorica‐based classification of the tintinnids. The assumption that the diaphragm‐like apparatus in the genera Salpingacantha and Salpingella is not homologous to the foldable ones in the genera mentioned above is supported by molecular and cytological features.  相似文献   

11.
The drilling mode of feeding is known from two clades of Gastropoda: Caenogastropoda and Heterobranchia. However, the level of convergence and parallelism or homology among these two lineages is unclear. The morphology of the buccal complex is well studied for drilling caenogastropods, but poorly known for drilling nudibranchs. It is also unclear whether the drilling feeding mechanism is similar between inside gastropods. Accordingly, a comparison between the feeding mechanisms of drilling nudibranchs and caenogastropods can help to understand the evolutional trends inside gastropods. In this study, we redescribe the morphology of the buccal complex of drilling dorid nudibranch Vayssierea cf. elegans, and compare it to that of previous investigations on this species and closely related dorid species. We describe the feeding mechanism of this species based on the obtained morphological and literature data and compare it to the feeding mechanisms described for drilling caenogastropods. The feeding apparatus of Vayssierea cf. elegans corresponds to the general morphology of the dorid buccal complex; that is, it has a similar arrangement of the buccal musculature and pattern of radular morphology. However, there are also adaptations to the drilling feeding mode similar to those found in Caenogastropoda: that is, specialized dissolving glands and lateral teeth with elongated pointed cusps; and even Sacoglossa: the specialized muscle for sucking. The feeding process of Vayssierea cf. elegans includes the same two stages as those described for drilling caenogastropods: (a) the boring stage, which is provided by mechanical and chemical activity, and (b) the swallowing stage.  相似文献   

12.
The morphology of mature larvae of Sisyra nigra was studied and documented with a broad spectrum of techniques. Special emphasis is on the cephalic anatomy and on the digestive tract. Cephalic structures are highly modified, with numerous autapomorphic conditions, including a globular head capsule, an extended area with large cornea lenses, a massive tentorium, a strongly developed prepharyngeal pumping apparatus with a horizontal arrangement of dilators, a sharp bend between the prepharynx and pharynx, and an unusual filter apparatus at the entrance of the large crop. The thoracic and abdominal muscle sets, and the legs are largely unmodified. Postcephalic apomorphies are conspicuous tergal setiferous tubercles, trifid setiferous pleural projections, single pretarsal claws, zigzag-shaped abdominal tracheal gills, and a dense vestiture of setae on the terminal abdominal segments. Mandibulo-maxillary stylets curved outwards are an unusual apomorphy also found in the semiaquatic larvae of Osmylidae. Semiaquatic or aquatic habits and secondarily multisegmented antennae are potential synapomorphies of these two groups and Nevrorthidae (Osmyloidea). A sistergroup relationship between Sisyridae and Nevrorthidae suggests that fully aquatic habits of larvae may be a synapomorphy of both families. A specialized terminal antennal seta is a potential groundplan apomorphy of Neuroptera, with secondary loss in Nevrorthidae and Ithonidae + Myrmeleontiformia, respectively. A trumpet-shaped empodium is likely an apomorphy of Neuroptera excluding Coniopterygidae and Osmyloidea, and the secondary loss an apomorphy of Ithonidae on one hand, and Myrmeleontiformia excl. Psychopsidae on the other.  相似文献   

13.
Tardigrade feeding apparatus is a complex structure with considerable taxonomic significance that can be schematically divided into four parts: buccal ring, buccal tube, stylet system, and pharynx. We analyzed the fine morphology and the tridimensional organization of the tardigrade buccal?Cpharyngeal apparatus in order to clarify the relationships between form and function and to identify new characters for systematic and phylogenetic studies. We conducted a comparative analysis of the cuticular structures of the buccal?Cpharyngeal apparatuses of twelve eutardigrade species, integrating data obtained by SEM and LM observations. Morphological diversity was observed and new cuticular structures such as the stylet coat of the stylet system were identified. The synthesis of the buccal?Cpharyngeal apparatus during molting was also analyzed obtaining a clear developmental sequence of its resynthesis. These findings lead us to redefine the previous interpretations of the functioning mechanisms of the buccal?Cpharyngeal apparatus and provide a more specific relationship between tardigrade diet and the anatomy of their feeding apparatuses. In addition, the detection by energy-dispersive X-ray spectroscopy of calcium in the stylets, buccal tube, and placoids of eutardigrade species (i.e., Milnesium tardigradum, Paramacrobiotus richtersi) indicates that CaCO3 incrustations are not an exclusive feature of heterotardigrades and lead to suppose that this trait was present in the ancestors of both classes.  相似文献   

14.
Freshwater fish evolution has been shaped by changes in the earth's surface involving changes in the courses of rivers and fluctuations in sea level. The main objective of this study is to improve our knowledge of the evolution of loricariids, a numerous and adaptive group of freshwater catfish species, and the role of geological changes in their evolution. We use a number of different phylogenetic methods to test the relationships among 52 representative taxa within the Neoplecostominae using 4676 bps of mitochondrial and nuclear DNA. Our analysis revealed that the subfamily Neoplecostominae is monophyletic, including Pseudotocinclus, with three lineages recognized. The first lineage is composed of part of Pareiorhina rudolphi, P. cf. rudolphi, and Pseudotocinclus; the second is composed of Isbrueckerichthys, Pareiorhaphis, Kronichthys, and the species Neoplecostomus ribeirensis; and the third is composed of Pareiorhina carrancas, P. cf. carrancas, Pareiorhina sp. 1, a new genus, and all the species of the genus Neoplecostomus, except N. ribeirensis. The relaxed molecular clock calibration provides a temporal framework for the evolution of the group, which we use for a likelihood‐based historical biogeographic analysis to test relevant hypotheses on the formation of southeast Brazil. We hypothesize that headwater capture events and marine regressions have shaped the patterns of distribution within the subfamily Neoplecostominae throughout the distinct basins of southeast Brazil.  相似文献   

15.
Summary The structure of the male reproductive systems of two species ofHaplognathia cf.lyra andH. cf.rosacea was described. The structure of the testes and the anterior portions of the sperm ducts in both species was found to be similar. However, considerable species differences were found between the structures of the glands and muscles associated with the reproductive systems. These were more elaborate inH. cf.lyra than inH. cf.rosacea. The former species possessed an H-shaped sperm duct gland, three distinct groups of penis muscles and a penis with two cell types and with a lumen. The latter species had paired sperm duct glands, no specialized penis muscles and a penis with only one cell type and without a detectable lumen. No open gonopore was observed in either species. The sperm presumably exit through a ventral tissue connection observed connecting the penis and the ventral epidermis. These findings were discussed in the light of Mainitz's (1977) theory concerning the primitive penis type within the Gnathostomulida.Abbreviations ap anterior-posterior penis muscles - bm basement membrane - csd common sperm duct - dl dorsal lumen of the penis - dp dorsal gland cells of the penis - dv dorsoventral muscles anterior to the penis - dw sperm duct wall cell - e epidermis - ex exit cell - g intestine - gl gut lumen - n nerve - p penis - sd sperm duct - sdg sperm duct gland - tw testes wall cell - vl ventral lumen of the penis - vp ventral gland cells of the penis This project was supported by NSF grant #GB 42211 (R.M. Rieger P.I.). The line drawings have been executed after our design by Ms. Linda McVay  相似文献   

16.
Recent investigations have suggested that a lack of circular muscle fibers may be a common situation rather than a rare exception in polychaetes. As part of a comparative survey of polychaete muscle systems, the F-actin musculature subset of Magelona cf. mirabilis and Prionospio cirrifera were labeled with phalloidin and three-dimensionally analyzed and reconstructed by means of cLSM. Obvious similarities are sublongitudinal lateral, circumbuccal, palp retractor, dominating dorsal longitudinal, perpendicular lateral and ventral transverse muscles. Differences between M. cf. mirabilis and P. cirrifera are: (1) two types of prostomial muscles (transversal and longitudinal) in M. cf. mirabilis versus one type (diagonal) in P. cirrifera; (2) one type of palp muscles (longitudinal) in M. cf. mirabilis versus three types (longitudinal, diagonal, circular) in P. cirrifera; (3) five ventral longitudinal muscles (ventromedian, paramedian, ventral) in M. cf. mirabilis versus four (two paramedian, two ventral) in P. cirrifera. Ventral and lateral transverse fibers are present in the thorax, but absent in the abdomen of M. cf. mirabilis. The triangular lumen of the pharynx in M. cf. mirabilis is surrounded by radial muscle fibers; three sets of pharynx diductors attach to its dorsal side. The unique features of P. cirrifera are one pair of brain muscles and segmentally arranged dorsal transverse muscles, the latter located outside the longitudinal muscles. The transverse lateral muscles are restricted to the sides and lie beneath the longitudinal muscles, a pattern described here for the first time. A true, outer layer of circular fibers is absent in both species of Spionida that were investigated.  相似文献   

17.
Annelids provide suitable models for studying regeneration. By now, comprehensive information is restricted to only a few taxa. For many other annelids, comparative data are scarce or even missing. Here, we describe the regeneration of a member of the Cirratulus cirratus species complex. Using phalloidin‐labeling and antibody‐stainings combined with subsequent confocal laser scanning microscopy, we provide data about the organization of body wall musculature and nervous system of intact specimens, as well as about anteriorly regenerating specimens. Our analyses show that C. cf. cirratus exhibits a prominent longitudinal muscle layer forming a dorsal muscle plate, two ventral muscle strands and a ventral‐median muscle fiber. The circular musculature forms closed rings which are interrupted in the area of parapodia. The nervous system of C. cf. cirratus shows a typical rope‐ladder like arrangement and the circumesophageal connectives exhibit two separate roots leading to the brain. During regeneration, the nervous system redevelops remarkably earlier than the musculature, first constituting a tripartite loop‐like structure which later become the circumesophageal connectives. Regeneration of longitudinal musculature starts with diffuse ingrowth and subsequent structuring into the blastema. In contrast, circular musculature develops independently inside the blastema. Our findings constitute the first analysis of regeneration for a member of the Cirratuliformia on a structural level. Summarizing the regeneration process in C. cf. cirratus, five main phases can be subdivided: 1) wound closure, 2) blastema formation, 3) blastema differentiation, 4) resegmentation, and 5) growth, respectively elongation. Additionally, the described tripartite loop‐like structure of the regenerating nervous system has not been reported for any other annelid taxon. In contrast, the regeneration of circular and longitudinal musculature originating from different groups of cells seems to be a general pattern in annelid regeneration. J. Morphol. 275:1418–1430, 2014. © 2014 Wiley Periodicals, Inc.  相似文献   

18.
The anatomy of the masticatory apparatus, the direction in which masticatory muscles act during mastication, and jaw muscle forces as estimated by muscle dry weight are compared between two murid rodents, the Japanese field mouse (Apodemus speciosus; subfamily Murinae) and the gray red-backed vole (Clethrionomys rufocanus; subfamily Arvicolinae). The occlusal forces exerted by the deep masseter and the anterior temporalis are large in C. rufocanus. Furthermore, in this species, the angle between the sagittal plane and the occlusal plane of the cheek teeth is larger than in A. speciosus. Therefore, a relatively large occlusal force can be generated in C. rufocanus. The estimated line of action of the anterior temporalis differs markedly between these two species. The functional significance of this difference is discussed relative to the adaptive dental characteristics for food processing, the forces required to masticate different types of food, and the forces that control mandibular forward movement. J Morphol 231:131–141, 1997. © 1997 Wiley-Liss, Inc.  相似文献   

19.
Boring sponges of the genus Pione (Hadromerida, Clionaidae) are easily recognizable due to their spiculation. However, species identification is challenging, as the potentially diagnostic morphological character states of different species often overlap. For this reason, this group of species is frequently referred to as the ‘Pione vastifica complex’, after the most well-studied species of the genus. Boring-sponge samples were collected in the Red Sea and identified as P. cf. lampa and P. cf. vastifica, respectively. So far, these two species names have usually been considered as valid, although some authors suggested them to be synonymous. Morphological analyses were performed on spicules and micro-erosion patterns by means of both light and scanning electron microscopy. Two apparent morphotypes can be distinguished, mainly by the growth form, but statistical analysis does not support a clear separation in two species. In addition, a DNA barcoding approach using sequences of CO1 has not identified any nucleotide sequence differences. These data support the hypothesis that P. cf. lampa and P. cf. vastifica from the Red Sea are conspecific.  相似文献   

20.
《Comptes Rendus Palevol》2008,7(8):529-539
In 2003, Werdelin has identified three hyaenid species from the Late Miocene of Kenya (Lothagam Formation), including two “ictitheres” – a newly erected Ictitherium ebu Werdelin, 2003, and Hyaenictitherium cf. parvum. The present article discusses the published evidence on the Kenyan hyaenids and explores additional cranial and postcranial characters useful for differentiation between the true ictitheres (i.e., the genera of the subfamily Ictitheriinae Trouessart, 1897) and some small members of the subfamily Hyaeninae Gray, 1869.  相似文献   

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