首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The monogenean Neobenedenia melleni (MacCallum, 1927) Yamaguti 1963 is a well-known and virulent pathogen in culture conditions recorded from the skin of many teleost fish species worldwide. Until now, N. melleni has not been reported from wild or cultured fish in Australian waters. This study documents a recent outbreak of N. melleni that occurred on Lates calcarifer (barramundi) cultivated in sea cages in Hinchinbrook Channel between Hinchinbrook Island and mainland Queensland, Australia, which resulted in the loss of 200,000 fish (50 tonnes). The origin of this outbreak is unclear because N. melleni has not been recorded from any wild host species in Australia and strict quarantine regulations exclude the possibility of its introduction on imported fish. We propose that N. melleni occurs naturally on wild populations of some teleost species in Australian waters and that the few surveys of wild fish conducted along the east coast have failed to report this species. The possibility that uncharacteristically low water temperatures led to the outbreak is discussed.  相似文献   

2.
We quantified Neobenedenia melleni from the skin of Caribbean surgeonfishes (Acanthuridae) from June through October 2005 and 2007. Prevalence, or mean intensity of infection, or both, varied significantly among the 3 species, and among sites and between years for the most heavily infected species, blue tang (Acanthurus coeruleus). Among 6 sites sampled, no more than 12% of ocean surgeonfish (Acanthurus bahianus) were infected, compared with 10 to 100% of A. coeruleus. The prevalence of infection among doctorfish (Acanthurus chirurgus), collected at only 1 of the sites, was intermediate between the other 2 species (46%). Mean intensity (range) of infection for the few infected A. bahianus was 1 (1) to 3 (1-8), compared with 1.3 (1-2) to 14.3 (1-59) for A. coeruleus, and 2.5 (1-8) for A. chirurgus. Expected abundance of N. melleni on A. coeruleus from shallow bay sites was greater than for those from non-bay sites. Higher infections on A. coeruleus may be attributable to differences in habitat use, or susceptibility to infection, or both, compared to other species. Among site and between-year differences may be associated with differences in benthic habitat, or water conditions, or both. This system seems ideal for future comparative studies on the relationship between environmental variables and parasites on Caribbean coral reefs.  相似文献   

3.
报道寄生于福建海水养殖鱼类高体蜥的玫氏新本尼登虫(单殖吸虫纲,分室科)的扫描电镜观察。虫体体表无棘,前吸器和后吸器盘状。副甲片、前钩和后钩位于鞘内,副甲片尖状,前钩和后钩弯钩状,边缘小钩呈辐射状排列于后吸器边缘。  相似文献   

4.
This study provides basic information on the occurrence of platyhelminths in the wild bullseye puffer (Sphoeroides annulatus) from Sinaloa, Mexico. Specimens of pufferfish were collected from 2 localities: Teacapan (n = 161) and Mazatlan (n = 66). Six species of platyhelminths were recorded: 2 monogeneans (Diclidophoridae: Heterobothrium ecuadori and Capsalidae: Neobenedenia melleni) and 4 digeneans (Apocreadiidae: Homalometron longisinosum, Lepocreadiidae: Bianium plicitum, Gorgoridae: Phyllodristomum mirandai, and Fellodistomidae: Lintonium vibex). This is the first record of the platyhelminth L. vibex in S. annulatus in the Mexican Pacific. Bianium plicitum was the most abundant species, and H. ecuadori was the most prevalent species. The fish from Teacapan had the higher prevalence of platyhelminths. Teacapan had higher specific richness index, whereas Mazatlan had a higher dominance, 3.098 (Teacapan = 2.38). A relative risk analysis showed that B. plicitum was more likely to be present on fish in water within the temperature range of 21-25 C and from Teacapan compared with fish from the warmer water (26-30 C) or from Mazatlan. Heterobothrium ecuadori was more likely to be present at water temperatures of 23-24.5 C on fish from Teacapan and when other ectoparasites were present. Neobenedenia melleni also was more likely to be present when other parasites were present.  相似文献   

5.
A new species of Sprostoniella is described from the gills of Chaetodipterus zonatus in Chamela Bay, on the west coast of Mexico. The new species differs from the 2 previously described congeners by having smaller testes each of which is not nearly as long as the ovary. It further differs from the type species, Sprostoniella multitestis, by having a poorly developed pair of accessory sclerites and the cecal diverticula are not confluent posteriorly. The new species also differs from Sprostoniella micrancyra, the other species of the genus, by having a shorter peduncle, the glands of Goto are smaller than the testes and ovary, and by having a slightly different haptoral structure, with 1 pair of hamuli rather than 2 pairs, and 1 central haptoral loculus instead of 2 loculi.  相似文献   

6.
Two different genetic types of tilapia, Mozambique tilapia Oreochromis mossambicus (MT), and Pargo-UNAM (PU; a synthetic hybrid whose genetic composition is 50% Florida red tilapia, 25% Rocky Mountain tilapia, and 25% red variant Oreochromis niloticus), were acclimatized to salinity and exposed to seawater from the Gulf of Mexico off the port of Veracruz, Mexico. Both fish types were infected by the monogenean ectoparasite Neobenedenia sp. and were killed within 2 to 3 wk. A crude worm extract was prepared from whole specimens collected during the original outbreak and used to immunize naive hosts of the same 2 types of tilapia. Immunized fish were then exposed to seawater, which resulted in Neobenedenia sp. infection. Immunization did not confer any protection against Neobenedenia sp. infection. However, the experiment enabled detailed analysis of the dynamics of infection and comparison of the effects of the parasite on the 2 host types. Although both tilapia types exhibited similar resistance to infection (as they harbored similar parasite burdens in the early phase of infection), PU is less tolerant to Neobenedenia sp., as a mean parasite abundance of ca. 50 worms fish-' killed all hosts within a fortnight, while 22% of MT survived up to 3 wk, harboring a mean parasite abundance of ca. 900 worms fish-'. Our results suggest that, as reported elsewhere, Neobenedenia sp. could negatively affect mariculture off the Mexican coast of the Gulf of Mexico.  相似文献   

7.
Calliobothrium pritchardae n. sp. is described from the whiskery shark, Furgaleus macki (Whitley, 1943), collected from Young Rocks in South Australia. This species differs from the 7 other known species of Calliobothrium in its possession of 2 rather than 3 posthook loculi. It is a further distinguished from all other Calliobothrium species except Calliobothrium evani in its possession of asymmetrical hooks. The lack of an accessory piece between the bases of the axial hooks and medial axial hook bases that are longer than the lateral axial hook bases further distinguish the new species from C. evani in which an accessory piece is present and the relative lengths of the medial and lateral axial hook bases are reversed. Scanning electron microscopy reveals spiniform microtriches on the neck and proximal bothridial surfaces, filiform microtriches on the apical bothridial surfaces, and a combination of the 2 microthrix types on the distal bothridial surfaces. The extended bases of the axial hooks are densely covered with spiniform microtriches. In addition, the number of testes within worms decreases substantially in progressively posterior (older) segments. The generic diagnosis of Calliobothrium is emended to include this species with 2 rather than 3 posthook loculi.  相似文献   

8.
A new species of Scyphophyllidium inhabits Mustelus mento near La Paloma, Uruguay. It resembles Scyphophyllidium giganteum from the Atlantic Ocean and specimens identified as S. giganteum from California by having anapolytic strobilae 155-258 mm long, 250-300 craspedote proglottids, scoleces 1.2-1.4 mm wide, necks 34-41 mm long, immature and mature proglottids wider than long, gravid proglottids wider than long to longer than wide, genital pores averaging 28% of proglottid length from the anterior end, relatively flat ovaries with digitiform lobes reaching the lateralmost extent of the testicular field, vitellaria in 2 fields converging toward the proglottid midline, straight and short cirrus sacs, and postvaginal vas deferens. The bothridia of the new species have accessory bothridial suckers that are smaller than those of California specimens; European specimens reportedly lack accessory bothridial suckers. The new species possesses a uterine duct that joins the uterus at the level of the genital atrium and ventral osmoregulatory ducts medial rather than lateral to the dorsal ducts, an arrangement described for Californian but not European specimens. It differs from both European and Californian specimens by having longer cirri, more testes per proglottid, prominent scales covering the neck, and vaginae and uterine ducts coiled immediately preovarially. Pithophorus, Marsupiobothrium, and Scyphophyllidium may form a clade.  相似文献   

9.
Intra-species morphological variation presents a considerable problem for species identification and can result in taxonomic confusion. This is particularly pertinent for species of Neobenedenia which are harmful agents in captive fish populations and have historically been identified almost entirely based on morphological characters. This study aimed to understand how the morphology of Neobenedenia girellae varies with host fish species and the environment. Standard morphological features of genetically indistinct parasites from various host fish species were measured under controlled temperatures and salinities. An initial field-based investigation found that parasite morphology significantly differed between genetically indistinct parasites infecting various host fish species. The majority of the morphological variation observed (60%) was attributed to features that assist in parasite attachment to the host (i.e. the posterior and anterior attachment organs and their accessory hooks) which are important characters in monogenean taxonomy. We then experimentally examined the effects of the interaction between host fish species and environmental factors (temperature and salinity) on the morphology of isogenic parasites derived from a single, isolated hermaphroditic N. girellae infecting barramundi, Lates calcarifer. Experimental infection of L. calcarifer and cobia, Rachycentron canadum, under controlled laboratory conditions did not confer host-mediated phenotypic plasticity in N. girellae, suggesting that measured morphological differences could be adaptive and only occur over multiple parasite generations. Subsequent experimental infection of a single host species, L. calcarifer, at various temperatures (22, 30 and 32?°C) and salinities (35 and 40‰) showed that in the cooler environments (22?°C) N. girellae body proportions were significantly smaller compared with warmer temperatures (30 and 32?°C; P?<?0.0001), whereas salinity had no effect. This is evidence that temperature can drive phenotypic plasticity in key taxonomic characters of N. girellae under certain environmental conditions.  相似文献   

10.
Examination of 290 red rockfish Sebastes capensis from two fishing grounds in northern Chile (Coquimbo 71°30' W; 30°0' S and Antofagasta 70°40' W; 23°30' S) revealed 8770 metazoan parasites, belonging to 18 taxa: Udonella caligorum (Udonellidae); Interniloculus chilensis , Paramicrocotyle sp. and Neobenedenia melleni (Monogenea); larval Gnathia sp., Cirolana sp. and Rocinela sp. (Isopoda); Helicometrina nimia , Diphtherostomum sp., Lecithochirium sp. and Pseudopecoelus sp. (Digenea); Ascarophis sebastodis , Anisakis sp. and larval Hysterothylacium sp. (Nematoda); Caligus cheilodactylus , Lepeophtheirus chilensis and Trifur tortuosus (Copepoda); larval Corynosoma australe (Acanthocephala). Ten species were found only in Coquimbo and three were found only in Antofagasta, species common to both localities were Pseudopecoelus sp., C. australe , Anisakis sp. and A. sebastodis . Evidence, based on qualitative differences between the parasite faunas of the red rockfish, suggests the existence of two discrete stocks.  相似文献   

11.
When oncomiracidia of Neobenedenia girellae (Monogenea, Capsalidae) were incubated in wells with lyophilized extracts of fish skin epithelia on the bottom, some attached to the well bottom with the haptor unfolded and shed the ciliated epidermal cells. Based on these morphological changes in oncomiracidia, we developed a new assay method to examine the attachment-inducing capacities of various fish extracts for oncomiracidia. Attachment-inducing capacities were found only in extracts of fish skin epithelium and not in other fish extracts. No significant difference in capacities was observed among extracts of skin epithelia of 4 fish species. Wheat germ lectin and concanavalin A suppressed capacities in extracts of skin epithelia of Japanese flounder and yellowtail, respectively. Suppressed capacities were recovered by adding sugars that bound specifically to these lectins. These results indicate that some sugar-related chemical substances that exist specifically in fish epithelium induce the attachment of N. girellae oncomiracidia.  相似文献   

12.
In vitro spermatophore formation and insemination of Neobenedenia girellae (Monogenea: Capsalidae, Benedeniinae) were recorded on video and described for the first time. Upon contact of two individuals, the anterior adhesive discs of the donor firmly attached to the dorsal tegument of the recipient and the donor's fore body strongly contracted such that the genital pore region protruded and the penis was pushed anteriorly to protrude through the genital pore. It is hypothesised that the donor penis mechanically damaged the tegument of the recipient. The sperm and spermatophore matrix were released together through the penis, which was placed under the left anterior attachment disc immediately behind the adhesive pad. The spermatophore matrix containing the spermatozoa became solid and attached to the dorsal surface of recipient's body. When observed under scanning electron microscopy, the spermatophores were irregularly shaped, with a diameter of 52–83 μm. Under light microscopy they consisted of a proximal eosinophilic matrix portion and a distal thin-walled portion containing spermatozoa. Both parts were enclosed with a thin outer casing. Insemination occurred during and after spermatophore formation. Three types of insemination were recorded, unilateral and mutual insemination and self-insemination. The presence of self-insemination indicates that even a single N. girellae on a cultured fish may cause a significant parasite infection in the entire aquaculture system.  相似文献   

13.
The holotype of the lower-middle Pliocene hyaenid Lycyaenops rhomboideae is redescribed and compared with contemporaneous hyaenids of the genera Lycyaena, Hyaenictis, Chasmaporthetes and Pliocmcuta. These comparisons show that the material represents a valid and distinct genus and species. The genus Lycyaenops is referred to the Chasmaporthetes lineage on the basis of its two-cusped m 1 talonid with reduced entoconid, reduced posterolingual cingulum cusp on p4 and premolar accessory cusps set in a straight line. It is distinguished from all other genera of that lineage by its smaller premolar accessory cusps, broad premolars and squared-off and very broad posterior premolar shelves. The species L. silberbergi, previously assigned to Chasmaporthetes, is also referred to Lycyaenops. It differs from L. rhomboideae in its greater development of the premolar accessory cusps and less developed posterior premolar shelves, but shares the broad, squared-off premolars. The interrelationships of Hyaenictis, Chasmaporthetes and Lycyaenops are at present best described by an unresolved trichotomy, with Lycyaena as its sister taxon.  相似文献   

14.
辽宁早白垩世义县组一新的三尖齿兽类   总被引:2,自引:1,他引:1  
描述了戈壁锥齿兽科 (Gobiconodontidae)一个新的属种———陆家屯弥曼齿兽 (Meeman nodonlujiatunensisgen .etsp .nov.)。标本产于辽宁西部朝阳市上园镇陆家屯下白垩统义县组一段的凝灰质砂岩层中 ,为一具完整齿列的左下颌骨。新属与戈壁锥齿兽 (Gobiconodon)共有以下区别于其他三尖齿兽类的特征 :2颗下门齿 ,i1增大 ,后部门齿、犬齿和前部前臼齿尖锥形 ,前臼齿具有高的中央尖和小的附尖 ,i~p1向前平伏。因此 ,新属被归入戈壁锥齿兽科。弥曼齿兽与戈壁锥齿兽及其相近属的区别在于 :下门齿和下犬齿更加平伏 ,i1在比例上更大 ,而i2则更小 ;最后一枚下前臼齿与第一枚下臼齿之间没有齿隙 ;前臼齿退化 ;下臼齿长度大于高度 ,主尖向后倾斜 ,与b尖和c尖相比 ,a尖较低 ,m1显著小于m2~ 4。新属下臼齿没有齿带 ,与爬兽 (Repenomamus)相似 ,而与戈壁锥齿兽不同。基于与爬兽齿列的对比 ,讨论了戈壁锥齿兽类的齿式 ,认为其应具有两颗门齿 ,而不是以前认为的 1颗门齿 ,从而将戈壁锥齿兽类下齿列齿式修订为 :2·1·2~ 3·5。  相似文献   

15.
We describe a new ancyrocephalid monogenean, Haliotrema cupensis n. sp., from a marine gobiid, Gobius cobitis (Pallas) from the Mediterranean Sea. This species differs from the other members of the genus by the morphology of the penis and accessory piece, the haptoral ornamentation and by possessing a larger testis. This is the first report of an ancyrocephalid on a marine gobiid and of a Haliotrema species in the Mediterranean Sea.  相似文献   

16.
Nerocila benrosei n. sp. is described from the hogfish, Lachnolaimus maximus (Walbaum), and the Spanish hogfish, Bodianus rufus (Linnaeus), (Perciformes: Labridae) from the northern Bahamas. Nerocila benrosei differs from all species of Nerocila by having the body of females 1.4-1.9 times as wide as long, instead of 2.0-3.0 times, and pleopods 1 and 2 lacking accessory lamellae. It differs from the only species of Nerocila with which it overlaps geographically, N. lanceolata (Say, 1818), by having the lateral margins of pleonites 1-5 strongly produced ventrally, coxae 5-7 manifestly shorter than the posterolateral projection of the respective pereonite, and a vaulted dorsal surface. The species of Nerocila in the northwestern Atlantic have almost mutually exclusive geographic ranges: New England to Panama, including Bermuda and the northern coast of Cuba (Nerocila lanceolata); Brazil to Trinidad and Tobago (Nerocila fluviatilis Schi?dte and Meinert, 1881); and the northern Bahamas and Bermuda (Nerocila benrosei). No species of Nerocila have been reported from the insular Caribbean. Nerocila benrosei appears to be highly host and site specific.  相似文献   

17.
The major reproductive events in the male eastern pipistrelle, are similar to those of other hibernating vespertilionids. The eastern pipistrelle stores epididymal spermatozoa throughout hibernation, a time when the testes are involuted but accessory gland activity is maintained. However, this species differs from others in that epididymal and testicular spermatozoa persist longer and the weights of the accessory glands are not strongly differentiated between winter and spring/summer. It is suggested that the reproductive period is extended in this species as a function of a more prolonged period of hibernation, resulting in only a brief period of sexual quiescence in mid-summer. The eastern pipistrelle (Pipistrellus subflavus) resembles the canyon bat (P. hesperus) in that some testicular spermatozoa persist during winter. Many aspects of the reproductive anatomy and chronology of these two species are similar; however, eastern pipistrelles apparently lack a seminal vesicle and possess a distinctly different baculum.  相似文献   

18.
19.
王伴月 《古脊椎动物学报》2001,39(1):24-42,T004,T006
根据新材料修订了Dianomys属及其两个种(D. obscuratus和D. qujingensis)的鉴定特 征。原定为D、obscuratus的P4应为dP4,原定的M1/2和m1/2分别被确认为M1和m2,原属 D.obscuratus的p4,实属D.qujingensis。D.qujingensis与D.obscuratus的区别除个体较大 外,还在于其上颊齿具分叉的后脊,m1具下中脊和p4具较发育的附加刺。另建立了一新属 (杨氏鼠Youngomys),包括二新种(云南杨氏鼠Y .yunnanensis、小杨氏鼠Y pisinnus)和一未 定种(Youngomys?sp.)。youngomys的主要特征为:颊齿比例上较窄长,齿冠较低,主尖钝,脊 较细而低;上臼齿长大于宽,后脊向原尖斜伸,内脊较低;下臼齿下原尖后臂较向后伸,无明显 的舌部,下内尖臂很弱,横向,不与下外脊连等。 Y pisinnuS与 Y yunnanensis的区别在于个体 较小,齿冠较低,脊更细弱,较显丘形,上臼齿次尖位置向舌侧移,具较明显的后小尖,和后脊 不与原尖连等。 用PAUP 3.1.1对亚洲古近纪的梳齿鼠类进行了系统分析,表明第四前臼齿的  相似文献   

20.
New collections of cestodes from the spiral intestines of the lanternsharks Etmopterus spinax and Etmopterus pusillus off the island of Faial, in the Azores, Atlantic Ocean, have yielded 2 new species of trypanorhynchs belonging to Aporhynchus. Both species share the distinctive lack of all elements of the rhyncheal system that are characteristic of this genus. The identity of Aporhynchus norvegicus is clarified to allow it to be distinguished from A. menezesi n. sp., which also parasitizes E. spinax. This new species differs conspicuously from its congeners in that its mature and gravid proglottids are wider than long, rather than longer than wide, and also in its lack of spinitriches on the scolex. Aporhynchus pickeringae n. sp., the new species from E. pusillus , differs from all of its congeners except A. norvegicus in that it is a relatively delicate worm with relatively fewer testes. It also possesses fewer proglottids and a wider pedunculus scolecis than does A. norvegicus. Sections through the scolex of A. menezesi n. sp. support use of the term bothriate, rather than difossate, in reference to the scolex configuration of some trypanorhynchs. A key to the 4 species of Aporhynchus is provided.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号