摘要:

As part of a transmission electron microscopic study of the embryological development in tardigrades, the ultrastructure of the pharynx was examined. The intent was to establish whether the pharyngeal muscle cells constitute an eclodermal myoepithelium (as in many aschelminth pharynges) or whether they are mesodermal (as in certain other aschelminth groups and among articulates). In the latter case the cuticle would be produced solely by specialized epithelial cells. The eutardigrade speciesHalobiotus crispaeKristensen, 1982, was investigated in four embryological stages, as a newly hatched juvenile, in the active adult stage, and in the hibernation stage pseudosimplex I. A comparison was made with the arthrolardigradeActinarctus doryphorusSchulz, 1935, in the active adult stage and in the simplex stage. The results indicate that the tardigrade pharynx is an ectodermal myoepithelium. The muscles appear to be truly cross‐striated and monosarcomerial. The phylogenetic implications of these findings are discussed briefl

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02338.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Freshwater and semiterrestrial tardigrades produce either smooth shelled eggs laid in the exuvium or ornamented eggs laid freely, in contrast to the more primitive marine heterotardigrades which have smooth shelled free‐laid eggs. Data are presented on the observation of free‐laid ornamented eggs in the primitive non marine heterolardigrade genusOreellaand in a number ot e.utardigrade genera includingEohypsibius, Amphilus, MinibiotusandMacrobiotus.These findings have provided a sound basis for the formulation of a hypothesis in which the evolution of the tardigrade egg can be explained by two separate events. The first is the acquisition of ornamentation and the second is the utilization of the exuvium for oviposition with subsequent loss of egg ornamentation. This hypothesis is consistent with new taxonomic arrangements within eutardigrade families and genera (based on character) of the animals) which have led to a more uniform assortment in terms of egg types. This means that egg type (smooth or ornamented) becomes a valid taxonomic character at the generic le

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02339.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Meiofauna from Chafarinas archipelago (western Mediterranean, N. Africa) were studied, and marine Tardigrada were identified to species level. A total of 15 species, belonging to families Stygarctidae, Halechiniscidac (Subfamilies Halechiniscinae, Florarctinae, Styraconyxinae and Tanarctinae), Batillipedidae, and Echiniscoididae, were found for the first time from the Alboran Sea and southwestern Mediterranean area. Four species and one subspecies are new records for the Mediterranean Sea:I'ioractus acer, F. asper, P. stellatus, Actinarctus doryphorusandEchiniscoides sigismundi hispaniensis.The male ofFloractus stellatus, previously unknown to science, is described. Many species have been recorded for the first time in different sedimentary environments, such as midlittoral pools, very shallow gravels, pools in a mixed rocky environment or betweenPosidonia oceanicameadows, ‘Amphioxus’ gravels, and coastal detri

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02340.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The ecological distributions of tardigrade species from six sites on Roan Mountain, Tennessee‐North Carolina, were determined in a study begun by D. R. Nelson in 1971. Three new species of eutardigrades were discovered in Nelson's study, but remained undescribed. A follow‐up to that study was initiated by K.L. McGlnthlin in 1988 to determine the long‐term stability of tardigrade populations at two of Nelson's original collection sites. Two of Nelson's three new eutardigrade species were rediscovered by McGlothlin, and one newPseudechiniscusspecies was found. The description of one of the eutardigrades,Hypsibius roanensis, was published previously. The remaining eutardigrade found during both studies, a new species ofCalohypsibius, is described here:Calohypsibius schusterisp

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02341.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Six species of tardigrades,Pseudechiniscus suillus, Macrobiotussp.,Hypsibius antarcticus, Ramajendas frigidus, Diphascon chilenenseandDiphascon pinguewere extracted from mosses and lichens from the ice‐free regions of the Windmill Islands near Casey Base, East Antarctica. Significant positive associations were found between the three common species (Pseudechiniscus suillus, Hypsibius antarcticus, Diphascon chilenense) and bryophytes, whereas strong negative associations were found between these species and algae and lichens. There were additional interspecific associations between the common species of tardigrades as well as between tardigrades, nematodes and rotifer

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02342.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Findings are reported from samples collected in tundra in Greenland, Iceland and the Svalbard Islands. In total 58, tardigrade species are reported, only 12 of which are common to all three areas. Forty‐three species are reported from Greenland (11 new to the country and two new to science); 33 species are reported from Iceland (14 new to the country); 21 species are reported from the Svalbard Islands (4 new to the archipelago). A description ofHypsibius pachyunguissp. novandFujiscon triodonsp. nov.(Eutardigrada, Hypsibiidae) is give

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02343.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Tardigrades were collected from three seepage spring sites at 549m on Short Mountain, Cannon County, Tennessee. Three terrestrial samples and three aquatic samples were taken monthly from each site. Terrestrial samples included mosses and lichens from rocks and fallen trees; one sample of leaf litter was also collected from two of the sites. Aquatic samples included sediment, decaying leaf litter, and aquatic plants. Specimens of tardigrades were mounted on individual slides in Hoyer's medium. Species were identified and photographed using phase and differential contrast microscopy. Twenty‐eight species representing 13 genera were recorded:Pseudechiniscus, Echiniscus, Doryphoribius, Ramazzottius, Hypsibius, Isohypsibius, Dipliascon, Platicrista, Itaquascon, Murrayon, Macrobiotus, Minibiotus, andMilnesium.One of thePseudechmiscusspecies and anIsohypsibiusspecies were new to science and are described in this pape

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02344.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

This is the first report on tardigrades from the Taimyr peninsula. Seventy‐one species of tardigrades were recorded, new to Russian fauna and two of which are new to science.Diphascon borealesp. nov.is closely related toD. brevipes(Marcus, 1936) but easily distinguished from it by claw structure and the absence of cuticular bars on the legs.Isohypsibius robertisp. nov.belongs to theelegansgroup of the genusIsohypsibius; it diners from other species in the group by having a long and thin buccal tube and large lunulae with small teeth on leg IV. The eggs ofRamazzottius montivagusare here described for the first time. The almost complete absence of tardigrades in and around Norilsk is noted. This is related to the heavy industrial pollution from a local nickel‐copper pl

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02345.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Habitat samples were collected near Menglun (21°55'N, 101°14'E) in the tropical Xishuangbanna Nature Reserve. Species recovered includeEchiniscus scabrospinosus, E. limai, Isohypsibius vretnamensis, Itaquascon ramazzottii, Macrobiotus harmsworthi, M. occidentalis, M. richtersi, andMilnesium tardigradum.This is the first record forE. scabrospinosus, E. limai, andI. vietnamensissince their original descriptions. These species plusM. richtersiandI. ramazzottiiare new records for China. This is the first report of Tardigrada from Yunnan Provinc

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02346.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1996.tb02328a.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY