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102. Thulinius

Author

Bertolani, Roberto

Subjects
Eutardigrada, Parachela, Tardigrada, Animalia, Biodiversity, Hypsibiidae, Taxonomy, Thulinius
Abstract

Thulinius nomen novum Diagnosis. Mouth opening with 12 small, partially fused peribuccal lamellae (Fig. 1 A) surrounded by six peribuccal lobes, sometimes subdivided into a larger number of irregular sublobes (Fig. 1 B); crest­shaped apophyses for the insertion of the stylet muscles on the buccal tube (Fig. 1 C), claws of Isohypsibius ­ type (Fig. 1, E,F,G). Etymology. Dedicated to Gustav Thulin, an excellent Swedish researcher. Type species. Isohypsibius stephaniae Pilato, 1974 Composition. T. stephaniae (Pilato, 1974), T. ruffoi Bertolani, 1981, T. augusti (Murray, 1907) Remarks. The three species are characterized by a buccal armature with a posterior band of fine teeth, followed by a line of bigger round teeth (Fig. 1 A,B), instead of transverse mucrones, as in several other genera of Hypsibiidae, Macrobiotdae and Eohypsibiidae, and by rows of macroplacoids, whose curvatures resemble a Grecian urn (Fig. 1 D). The species differ together mainly for the shape of the cuticular structures of the legs. Thulinius ruffoi (Fig. 1 F) differs from T. stephaniae (Fig. 1 G) in having thinner claws with longer tapering basal tract, lunules evident and a less prominent cuticular bar below the claws of the first three pair of legs (other than for a more slender body). Thulinius augusti differs from the other two species by the presence of a particularly long and thin basal tract of the claw, especially in the external one, from T. stephaniae also by a weaker cuticular bar below the claws of the first three pair of legs, and from T. ruffoi also by the absence of lunules. The subdivision of the lobes into sub­lobes (Fig. 1 B) is another possible difference between T. augusti and the other two species.

Published
2003
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105. Tardigrada

Author

Rebecchi, Lorena, Guidi, A., and Bertolani, Roberto

Subjects
ultrastructures, tardigrada, male reproductive apparatus, spermatozoa
Published
2000

110. Tardigrada

Author

Bertolani, Roberto and Rebecchi, Lorena

Subjects
reproduction, germ cells, sex condition, fertilization, parental cares, Tadigrada, development
Published
1999

111. Front Matter

Author

Rebecchi, Lorena, primary, Nelson, Diane R., additional, Bertolani, Roberto, additional, and Fontoura, Paulo, additional

Published
2013
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117. What if the claws are reduced? Morphological and molecular phylogenetic relationships of the genus Haplomacrobiotus May, 1948 (Eutardigrada, Parachela).

Author

Cesari, Michele, Vecchi, Matteo, Palmer, Aparna, Bertolani, Roberto, Pilato, Giovanni, Rebecchi, Lorena, and Guidetti, Roberto

Subjects
TARDIGRADA, ANIMAL species, X-ray spectroscopy, ELECTRON microscopy
Abstract

Eutardigrada systematics relies mainly on the morphology of the sclerified structures of the animals. In particular, the main division of Parachela into four superfamilies relies heavily upon claw morphology; however, this character, alone, may be either inadequate or useless for tardigrades with no claws, or when secondary claw branches are reduced or absent, as in the case of species belonging to the genus Haplomacrobiotus. This is a very uncommon genus, so far reported only in North America. The systematic position of this genus has been debated since its description, having first been placed in the family Macrobiotidae (Macrobiotoidea) and then in the family Calohypsibiidae (Hypsibioidea). Currently, the position of the supposedly related genus Hexapodibius is still debated, being attributed to Isohypsibiidae (Isohypsibioidea) or to Calohypsibiidae (Hypsibioidea), i.e. to two different superfamilies. The morphological (light and electron microscopy), chemical (X-ray spectroscopy), and molecular ( 18S and 28S genes) analyses of a population of Haplomacrobiotus utahensis Pilato & Beasley, 2005 from Snow Canyon State Park (Utah, USA) allowed us to validate the position of this genus within Isohypsibioidea. Our integrated findings placed Haplomacrobiotus in a close relationship with the genus Hexapodibius, and allowed us to erect the new family Hexapodibiidae, comprising the genera Hexapodibius, Parhexapodibius, Haplomacrobiotus, and Haplohexapodibius. [ABSTRACT FROM AUTHOR]

Published
2016
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118. Interspecific relationships of tardigrades with bacteria, fungi and protozoans, with a focus on the phylogenetic position of Pyxidium tardigradum (Ciliophora).

Author

Vecchi, Matteo, Vicente, Filipe, Guidetti, Roberto, Bertolani, Roberto, Rebecchi, Lorena, and Cesari, Michele

Subjects
TARDIGRADA, ANIMAL populations, MICROORGANISMS, BIOMARKERS, LITERATURE reviews
Abstract

Symbiosis can be defined as an interaction between individuals of different biological species. Despite the small number of studies solely devoted to symbiotic interactions between tardigrades and micro-organisms (such as bacteria, fungi and protozoans), numerous reports can be found in the literature, especially as notes in faunal and alpha-taxonomy studies. Here, we review the literature and compile a list of the interactions between tardigrades and micro-organisms, excluding those that constitute food for tardigrades. Furthermore, a genetic study on a tardigrade symbiophoront, the ciliate Pyxidium tardigradum van der Land, 1964 was performed. There are a few records of P. tardigradum on both European and Asian tardigrades, but no morphological discrepancies among populations have been observed. We present here the phylogenetic positioning for P. tardigradum inferred by using nuclear ribosomal markers (18S and 5.8S). The phylogenetic trees showed all P. tardigradum specimens grouped together, and belonging to the family Operculariidae, order Operculariida. Moreover, a study based on the genetic distances between a Portuguese and an Irish population of P. tardigradum was performed using internal transcribed spacers ITS1 and ITS2. The ITS1 and ITS2 sequences showed differences between populations, leading us to hypothesize the presence of cryptic species. [ABSTRACT FROM AUTHOR]

Published
2016
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120. Experiences with dormancy in tardigrades

Author

Bertolani, Roberto, Guidetti, Roberto, Jönsson, K. Ingemar, Altiero, Tiziana, Boschini, Deborah, Rebecchi, Lorena, Bertolani, Roberto, Guidetti, Roberto, Jönsson, K. Ingemar, Altiero, Tiziana, Boschini, Deborah, and Rebecchi, Lorena

Abstract

Tardigrades often colonise extreme habitats, in which they survive using both types of dormancy: quiescence and diapause. Together with nematodes and bdelloid rotifers, tardigrades are known to enter quiescence (with several forms of cryptobiosis: anhydrobiosis, cryobiosis, anoxybiosis, osmobiosis) at any stage of their life cycle, from egg to adult. Entering anhydrobiosis, tardigrades contract their body into a so-called tun, loosing most of their free and bound water (>95%), synthesizing cell protectants (e.g., trehalose, glycerol, heat shock proteins) and strongly reducing or suspending their metabolism. Our research on cryptobiosis focused on some ecological and evolutionary aspects. We evaluated: i) the long-term anhydrobiotic survival by comparing quantitative data on recovery from naturally induced desiccation in several species of tardigrades; ii) differences in survival patterns between species and populations by experimentally inducing anhydrobiosis and cryobiosis; iii) phenotypic factors affecting anhydrobiotic survival. As regards diapause, we considered encystment and eggs. Encystment involves at least the synthesis of new cuticular structures. Morphological changes during cyst formation are more complex than those involved in tun formation. We analyzed more in detail encystment processes, comparing a semiterrestrial with a limnic species. Several inter-specific differences have been identified, other than the production of two types of cysts in the semiterrestrial species. Our analysis of life history traits of a laboratory reared strain of a soil tardigrade revealed a particular hatching phenology that involved the production of both subitaneous and resting eggs. The latter need a cue to hatch (dehydration followed by re-hydration). In addition, the evolutionary meaning of dormancy in tardigrades is discussed

Published
2004
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128. Tardigrada

Author

Bertolani, Roberto

Subjects
reproduction, Tardigrada, asexual propagation, parthenogenesis
Published
1994

140. Tardigrada

Author

Bertolani, Roberto

Subjects
Sexual differentiation, tardigrades
Published
1992

145. Tardigrada

Author

Bertolani, Roberto

Subjects
Tardigrades, fertilization, parental care, development
Published
1990

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