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1.
Fumio Iwata 《Hydrobiologia》1998,378(1-3):199-213
Two different tributyltin (TBT)-induced virilisation phenomena in prosobranch snails – intersex in Littorina littorea and imposex in Nucella lapillus – are compared in order to facilitate their simultaneous use in geographical large scale effect monitoring surveys. Imposex in dogwhelks is a more sensitive biomarker and should be used in areas that are only slightly or moderately contaminated with TBT (ambient TBT concentrations < 2.0 ng as Sn l-1). The assessment of intersex intensities in periwinkle populations has considerable advantages in areas with higher TBT concentrations and should be used also wherever dogwhelks are absent irrespective of the TBT exposure level. The intersex index (ISI) and vas deferens sequence (VDS) index are proposed as the most suited parameters for effect monitoring purposes. The geographical uniformity of intersex and imposex is analysed and proven for the coasts of Ireland, France, and Germany. A relative loss of TBT sensitivity in females can be found, but to a varying extent in both species. The implications of this result for biological TBT effect monitoring programmes are discussed in light of the fact that intersex and imposex have both been found to be irreversible. Because it is the objective of these programmes to assess current TBT contaminations and resulting biological effects, only relatively young specimens should be considered in the sampling strategy.  相似文献   

2.
Fumio Iwata 《Hydrobiologia》1988,156(1):115-124
Summary The polystiliferous hoplonemertean Sagaminemertes nagaiensis (Iwata, 1957) has been redescribed.A distinct pre-cerebral region is wanting. The rhynchocoel opens directly at the tip of the head, whilst the mouth opens seperately below the ventral commissure of the brain which is situated at the anterior end of the head. The dorsal ganglia are well developed and extend posteriorly far behind the ventral ganglia. The cerebral sense organs are situated behind the brain and possess posterior ciliated canals. Cephalic glands are poorly represented, but ocelli are well developed. The sickle-shaped basis of the proboscis bears about 20 central stylets. The caecal appendages of the rhynchocoel are arranged pseudometamerically throughout the body. The foregut is straight, consisting of mouth, oesophagus, stomach and pylorus. Intestinal caeca and lateral diverticula are present. The cephalic lacunae have no anterior anastomosis. A cerebral lacuna is present, there is a rhynchocoel vessel, but transverse vessels are absent. The protonephridia extend throughout the foregut region. Mature spermatogonia are well developed.A systematic discussion of Sagaminemertes nagaiensis suggests that it is taxonomically close to Siboganemertes weberi in the archireptantic family Siboganemertidae.  相似文献   

3.
Fumio Iwata 《Hydrobiologia》1993,266(1-3):185-201
Some morphological features with major systematic significance are recorded in the heteronemertean Paralineopsis taki gen. et sp. nov. from Onomichi, Japan as follows: horizontal band of specialized epithelium extends from near apex to the opening of the cerebral organ canal on either side of the head; precerebral region filled with gelatinous (hyaline) connective tissue in which longitudinal muscles are absent; body wall muscles do not accompany rhynchodaeal invagination; rhynchodaeum initially only epidermal; inner longitudinal muscles of ventral wall of cephalic blood lacuna become intimately associated with rhynchodaeum forming a dorsal saddle over it; cerebral organs do not penetrate inner longitudinal muscles, and do not contact blood vascular system; proboscideal diaphragm post-cerebral; outer longitudinal muscles absent throughout body; longitudinal muscles of proboscis derived from inner longitudinal musculature. The systematic relationship of P. taki and Paralineus elisabethae (Schütz, 1911) from Villefranche, France is discussed.  相似文献   

4.
A new genus, Papillonema gen.n., is erected to accomodate the two species P. danieli gen. et sp. n. and P. clavatum (Gerlach, 1957) comb.n. from intertidal sediments of a tropical mangrove. Papillonema gen.n. is characterized by prominent papilliform labial sensillae, an elongate muscular terminal bulb (up to 60% of pharyngeal length), and three precloacal supplements. Comments are given on the use of the terms head capsule, head region, and cervical setae.Abbreviations a: body length divided by maximum body diameter - abd: anal body diameter - amph %: diameter of the amphid as a percentage of the corresponding head diameter - aw: amphidial width - b: body length divided by pharyngeal length - bdcs: body diameter at level of the cephalic setae - bdnr: body diameter at level of nerve ring - c: body length divided by tail length - cs: length of cephalic setae - da: distance from anterior to anus - dcs: distance from anterior edge to cephalic setae - dnr: distance from anterior edge to nerve ring - dv: distance from anterior to vulva - gub: length of the gubernaculum - hw: head width - L: body length - Isp: length of sperm cells - mbd: maximum body diameter - mbd ph: body diameter at level of pharynx - ph: pharyngeal length - spic: length of spicules measured along the arc - t: tail length - tmr: length of non-annulated tail end - V: position of vulva as a percentage of the total body length from anterior - wsp: width of sperm cells  相似文献   

5.
Notogaeanemertes folzae gen. n., sp. n., a monoecious and ovoviviparous hoplonemertean, is described from the supra-littoral at Kaikoura, New Zealand. It shares more characters with group I terrestrial nemerteans than with group II which brings into question the significance of certain features in the systematics of semiterrestrial/terrestrial nemerteans.  相似文献   

6.
On the basis of the revision of the type material of Anoplostrongylus delicatus Schwartz, 1927, and new specimens collected from Tadarida brasiliensis mexicana (Saussure, 1860) in 4 arid localities from Mexico, we describe a new genus (Tadaridanema n. gen.), to which A. delicatus is transferred (as Tadaridanema delicatus (Schwartz, 1927) n. gen., n. comb.). This new genus differs from all other genera included in Anoplostrongylinae by having ray 2 larger than ray 3. In addition, T. delicatus can be differentiated from the type species of Anoplostrongylus (Anoplostrongylus paradoxus (Travassos, 1918)) because it possess vestibular branches equal in length, cephalic inflation divided into 2 regions, and synlophe with many small ridges at the midbody level, whereas in T. delicatus, vestibular branches are equal in size, cephalic inflation is simple in structure, and the synlophe has only 2 well-developed dorsal cuticular ridges.  相似文献   

7.
Australiformis n. gen. is erected for Echinorhynchus (Gigantorhynchus) semoni Linstow, 1898, from Australian and New Guinea marsupials. The new genus differs from Moniliformis and Promoniliformis in lacking spiral muscles in the outer wall of the proboscis receptacle. Linstow's species, E. semoni, is redescribed from abundant material from Peramelidae and Dasyuridae from Australia and New Guinea.  相似文献   

8.
Yamaguchia toyensis n. sp., n. gen. is described from an oligotrophic caldera lake, Lake Toya, Hokkaido, Japan. Although the taxonomic affinities are unknown, the genus differs from all other Lumbriculidae in having the combination of testes and atria in X, a single, prosoporous male funnel per atrium, and spermathecae in XI. Unlike other Japanese lakes that have thus far been surveyed, Lake Toya supports abundant populations of lumbriculids in the profundal benthos.  相似文献   

9.
Amoebogregarina nigra n. gen., nov. comb. (Eugregarinida: Gregarinidae) is described from trophozoites, gamonts, associations, gametocysts, and oocysts collected from adult Melanoplus differentialis (Orthoptera: Acrididae) in Nemaha County, Nebraska. Host alimentary canals were examined for eugregarine parasites. Gregarines encountered were fixed as permanent specimens or subjected to a series of morphometric measurements. Morphometric analysis indicated the presence of Gregarina nigra, a poorly described taxon reported from a variety of Nearetic grasshopper species, Examination of G. nigra revealed a metamorphic epimerite assimilated by the protomerite on maturity. This epimerite-protomerite complex is unique within Gregarinidae, prompting creation of the genus Amoebogregarina. Amoebogregarina nigra is the type species in new combination. Gregarina indianensis is recognized as a junior synonym of A. nigra.  相似文献   

10.
Sauertylenchus labiodiscus n. gem, n. sp. is described and illustrated from soil around Rhagodia sp. in Australia. It can be distinguished from the most closely related genus Tylenchorhynchus Cobb, 1913 by the distinctly set-off, rounded, lip region with a conspicuous labial disc, and long thin stylet. The face view and spicules of Sauertylenchus labiodiscus are illustrated with scanning electron micrographs. The subfamilies Tylenchorhynchinae and Merlininae ale discussed.  相似文献   

11.
12.
Here we describe the first species of sanguinicolid blood fluke (Trematoda: Digenea) from a polynemid fish. Chaulioleptos haywardi n. gen., n. sp. is described from Filimanus heptadactyla Cuvier, 1829 (Perciformes: Polynemidae), the sevenfinger threadfin from Sandgate, Moreton Bay (southeast Queensland, Australia). Chaulioleptos haywardi differs from existing sanguinicolid genera in the combined possession of the following 7 characters: 2 testes, an entirely postovarian uterus, a uterine chamber, separate genital pores, an H-shaped intestine with abbreviated anterior caeca, tegumental spines in incomplete ventro-marginal transverse rows that are continuous along the length of the body, and vitelline follicles that are tightly compacted and subsequently appear to form a solid branching mass occupying the area anterior to intestinal bifurcation and extending posteriorly to the level of the posterior margin of the anterior testis. Chaulioleptos haywardi is most closely related to Paracardicola Martin, 1960 and Adelomyllos Nolan and Cribb, 2004.  相似文献   

13.
The monotypic Kamegainema n. gen. is proposed for Filaria cingula, a subcutaneous parasite of cryptobranchids. Examination of female specimens recently collected from the Japanese giant salamander, Andrias japonicus, revealed that it belongs to Dracunculidae. Kamegainema is closest to Protenema Petter and Planelles, 1986, the only other dracunculid genus known from Amphibia, but is readily distinguished by having prominent cuticular bosses. Kamegainema cingulum is redescribed.  相似文献   

14.
Poinar G  Poinar R 《Protist》2004,155(3):305-310
A trypanosomatid (Trypanosomatidae: Kinetoplastida) associated with a blood-filled female sand fly in Cretaceous Burmese amber, is described in the new genus and species, Paleoleishmania proterus. The genus Paleoleishmania is established as a collective genus for digenetic fossil trypanosomes associated with sand flies. Amastigotes, promastigotes and paramastigotes are described. Paleoleishmania proterus is the first fossil kinetoplastid and provides a minimum age for the digenetic Trypanosomatidae. Its discovery indicates that vector-borne pathogens had been established by the Early Cretaceous.  相似文献   

15.
Sokolova YY  Fuxa JR 《Parasitology》2008,135(8):903-929
Thelohania solenopsae is a unique microsporidium with a life-cycle finely tuned to parasitizing fire ant colonies. Unlike other microsporidia of social hymenopterans, T. solenopsae infects all castes and stages of the host. Four distinctive spore types are produced: diplokaryotic spores, which develop only in brood (Type 1 DK spores); octets of octospores within sporophorous vesicles, the most prominent spore type in adults but never occurring in brood; Nosema-like diplokaryotic spores (Type 2 DK spores) developing in adults; and megaspores, which occur occasionally in larvae 4, pupae, and adults of all castes but predominantly infect gonads of alates and germinate in inseminated ovaries of queens. Type 2 DK spores function in autoinfection of adipocytes. Proliferation of diplokaryotic meronts in some cells is followed by karyogamy of diplokarya counterparts and meiosis, thereby switching the diplokaryotic sequence to octospore or megaspore development. Megaspores transmit the pathogen transovarially. From the egg to larvae 4, infection is inapparent and can be detected only by PCR. Type 1 DK spore and megaspore sequences are abruptly triggered in larvae 4, the key stage in intra-colony food distribution via trophallaxis, and presumably the central player in horizontal transmission of spores. Molecular, morphological, ultrastructural and life-cycle data indicate that T. solenopsae must be assigned to a new genus. We propose a new combination, Kneallhazia solenopsae.  相似文献   

16.
The generic diagnosis of the male imago of a new genus of the subfamily Orthocladiinae (Chironomidae), Saetheriella is given. The genus is characterized by protruding, hairy eyes; antenna with straight, apical seta; antepronotum reduced; squama without setae; Cu1 distinctly downcurved; and anal point short, triangular, covered with microtrichia and with two strong, lateral setae. The genus is close to Gynnidocladius Sublette & Wirth, Unniella Sæther and Parakiefferiella Thienemann. The distribution of the genera shows evidence of a Gondwanian connection. The male imago of the only included species S. amplicristata sp. n. is described.  相似文献   

17.
18.
The genus Katatopygia gen. n. is proposed for the Boletina erythropyga/punctus-group that was first introduced by Garrett (1924, 1925) and currently comprises eight described species. Molecular studies have strongly indicated that this group forms a monophyletic sister-group to a clade consisting of all other Boletina, Coelosia and Gnoriste, and its monophyly is supported by morphological data as well. The new genus includes the following species: Katatopygia antoma (Garrett, 1924), comb. n., Katatopygia antica (Garrett, 1924), comb. n., Katatopygia erythropyga (Holmgren, 1883), comb. n.,Katatopygia hissarica (Zaitzev & Polevoi, 2002), comb. n., Katatopygia magna (Garrett, 1925), comb. n., Katatopygia laticauda (Saigusa, 1968), comb. n., Katatopygia neoerythropyga (Zaitzev & Polevoi, 2002), comb. n. andKatatopygia sahlbergi (Lundström, 1906), comb. n., all transferred from Boletina. Katatopygia sahlbergi is found to be a senior synonym of Boletina punctus Garrett, 1925, syn. n. A phylogeny based on morphological data and using parsimony analysis yielded four most parsimonious trees where the new genus is retrieved as monophyletic with high support. Katatopygia neoerythropyga is found to be the sister-taxon to all other species that form two clades, one with Katatopygia sahlbergi-like species and one with Katatopygia erythropyga-like species. A key to males of Katatopygia is provided.  相似文献   

19.
Elke Willen 《Hydrobiologia》1995,302(3):241-255
Male and female of a new genus and species of the family Laophontidae, Archilaophonte maxima, are described. The specimen was found in the high Antartic (Weddell Sea) and apprears to be the most primitive genus up to now within the superfamily Laophontoidea as defined by Huys (1990). Based on its setation of legs and mouth parts, however, it can be placed unequivocally into the family Laophontidae. Archilaophonte maxima gen. n. shows close affinities to the laophontid genus Esola Edwards 1891. Both genera form a monophyletic group which is interpreted here as the first and most primitive offshot in the evolution of the Laophontidae. The synapomorphies of the former lineage are the shape of the protopodite of the P1 and shape and setation of the female P5.  相似文献   

20.
An almost complete skull of a new ichthyosaur from the Middle Triassic Grenzbitumenzone Beds of Monte San Giorgio (Kanton Tessin, Switzerland) represents one of the most complete and best preserved finds of a large Triassic ichthyosaur cranium. Its affinites with other Triassic ichthyosaur taxa are discussed and it is demonstrated to represent a new genus and species,Mikadocephalus gracilirostris, which does not fit into any of the currently recognized families of Triassic ichthyosaurs. Remarkable similarities in cranial structure exit to postTriassic ichthyosaurs, with which a number of important apomorphies are shared.  相似文献   

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