Topic
Halobiotus
About: Halobiotus is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 66 citations.
Papers
TL;DR: The buccopharyngeal apparatus from three well-known species are described in detail and preliminary attempts to interpret the function of some of the structures are presented, together with the possible artifacts and difficulties the method may cause.
Abstract: The buccopharyngeal apparatus of several species of tardigrades, including both heterotardigrades and eutardigrades, has been prepared for scanning electron microscopy (SEM) by using a new method developed and refined for this purpose. The buccalpharyngeal apparatus from three well-known species are described in detail and preliminary attempts to interpret the function of some of the structures are presented. The chosen species are used as examples and the new findings are compared to studies from the literature. The species used are: Echiniscoides sigismundi , Halobiotus crispae and Milnesium tardigradum . A redescription of the buccopharyngeal apparatus, in particular the stylets, the stylet supports, the stylet sheaths and their interrelationships, is presented for each species. For H. crispae the cuticular elements of the pharynx are also redescribed from this material. The potential for new information available with this method is discussed, together with the possible artifacts and difficulties the method may cause.
36 citations
TL;DR: The findings suggest polyphyly of the Hypsibiidae, and thus multiple evolutions of some structures currently applied as diagnostic characters (e.g., claws, buccal apophyses) within the Eutardigrada.
Abstract: To extend data on 18S rDNA gene phylogeny within the Eutardigrada and to provide additional information on unclear taxonomic status of a glacier tardigrade Hypsibius klebelsbergi, gene sequences from seven tardigrade species of the family Hypsibiidae (Hypsibius klebelsbergi, Hypsibius cf. convergens 1, Hypsibius cf. convergens 2, Hypsibius scabropygus, Hebensuncus conjungens, Isohypsibius cambrensis, Isohypsibius granulifer) were analysed together with previously published sequences from ten further eutardigrade species or species groups. Three distinctly separated clades within the Hypsibiidae, 1) the Ramazzottius - Hebesuncus clade, 2) the Isohypsibius clade (Isohypsibius, Halobiotus, Thulinius), and 3) the Hypsibius clade (Hypsibius spp.) have been obtained in each of four phylogenetic trees recovered by Maximum Parsimony, Neighbour Joining, Minimum Evolution and UPGMA. Hybsibius klebelsbergi has been located always within the Hypsibius clade. The detailed sister group relationship was not resolved adequately, but there is robust support for a sister group relationship between the Hypsibius clade and the remaining clades. We cannot exclude that the Ramazzottius - Hebesuncus clade is a sister group of the Macrobiotus clade. Our findings suggest polyphyly of the Hypsibiidae, and thus multiple evolutions of some structures currently applied as diagnostic characters (e.g., claws, buccal apophyses).
36 citations
TL;DR: The structure and arrangement of sensory organs in the tardigrade Halobiotus stenostomus (Richters 1908) have been studied using transmission and scanning electron microscopy techniques and a receptor ending without a collar is described for the first time inTardigrades.
Abstract: The structure and arrangement of sensory organs in the tardigrade Halobiotus stenostomus (Richters 1908) have been studied using transmission and scanning electron microscopy techniques. The sensory organs found on the head of H. stenostomus are as follows: the circumoral sensory field, cephalic papillae, anterolateral and posterolateral sensory fields, and suboral sensory region. Four types of ciliated receptor structures are described in the sensory fields. The lateral sensory fields contain two types of receptor endings, dense and lucent, which differ in the presence or absence of a collar and in the structure of the outer dendrite segment. Two more types of receptor endings, ultrastructurally differing from the lateral sensory field receptors, are located in the suboral sensory region. Receptors with an asymmetric collar have been found, and a receptor ending without a collar is described for the first time in tardigrades. Unlike in other species studied, the sensory organs of H. stenostomus lack the lymph cavity surrounding the outer receptor segment. Similarity and differences in the ultrastructure of receptors between H. stenostomus and other species of Eutardigrada and Heterotardigrada are discussed.
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2012 | 1 |
| 2007 | 1 |
| 2001 | 1 |