1,721,187 research outputs found
Yours faithfully and obliged Charles Darwin: la lettera di Darwin alla Società dei Naturalisti in Modena
No full textVengono raccontate le vicissitudini del ritrovamento di una lettera autografa di Darwin alla Società dei Naturalisti in Modena. Viene valutata la sua autenticità e se ne ripercorre la storia
Evolution of egg deposition strategies, exaptations of exuvia, and thanatochresis in tardigrades
Full text linkThe cuticle is the tardigrade exoskeleton that, limiting animal growth, needs to be periodically shed. New cuticles must be
formed (within the old ones) before getting rid of the obsolete exoskeletons at the end of moulting process. After ecdysis
(the release of the old cuticle), the exuvia has different destinies according to tardigrade evolutionary lines. In the marine
tardigrades (Heterotardigrada), the exuvia is lost and useless, while in the other taxa, it acquires interesting uses to be considered
exaptations, since the cuticle previously shaped by natural selection for a function (i.e. as exoskeleton) is coopted
for new adaptive scopes. These are related to egg deposition, parental care, mating, and diapause. Egg deposition within
the exuvia is one of the three different egg deposition strategies developed by tardigrades: smooth eggs can be laid freely or
within the exuvia, while ornamented eggs are laid freely. A new scenario for the evolution of such egg deposition strategies
is characterised by five schematic steps: smooth eggs laid freely (ancestral state), synchronization of egg maturation with
moulting (developed in tardigrade ancestor in sea), use of the exuvia for oviposition (for enhanced mechanical and physiological
egg protection), acquisition of egg ornamentation, and ornamented eggs laid freely (related to a risk-spreading strategy).
An interesting thanatochresis case related to the release of free eggs in crustaceans exuviae, convergently developed in two
distant taxa of eu- and heterotardigrades, is presented and discussed
Sulle orme di Darwin: alla ricerca del progenitore comune
No full textApprocci filosofici e metodologici per derivare e rappresentare le relazioni evolutive tra gli organism
Two New Species Of Macrobiotidae (Tardigrada : Eutardigrada) From The United States Of America, And Some Taxonomic Considerations Of The Genus Murrayon
No full textVolume: 111Start Page: 663End Page: 67
I visitatori hanno detto di noi.
No full textIndagine sui 30000 visitatori della mostra su Darwin realizzata a Modena nel 2009-2010
Revision of the genus Pseudodiphascon (Tardigrada, Macrobiotidae), with the erection of three new genera
No full textA flexible but non-annulated buccal tube was used to erect the subgenus Pseudodiphascon , later raised to genus level (type species Macrobiotus inflexus ). However, the presence of a flexible (but non-annulated) buccal tube in the holotype and paratype is due to the moulting simplex stage of both animals. Therefore Macrobiotus inflexus must be considered species dubia . The other species to date attributed to Pseudodiphascon differ from the type species of the genus in the presence of a pharyngeal tube that appears annulated. Because of this and other characters, they do not conform to the definition of Pseudodiphascon and cannot be attributed to this genus, which must be considered genus dubium . The characters of the claws and of the buccal-pharyngeal apparatuses led us to describe three new genera: Biserovus gen. n.: claws without a differentiated basal portion, annulated pharyngeal tube, peribuccal lamellae present; Minilentus gen. n.: claws of ' hufelandi type', annulated pharyngeal tube, peribuccal lamellae absent; Insuetifurca gen. n.: claws of modified ' hufelandi type', annulated pharyngeal tube, peribuccal lamellae present, stylet furcae of a peculiar shape. Pseudodiphascon diphasconides lacks annulation in the buccal tube and is transferred to the genus Minibiotus
Una mostra dedicata a Charles Darwin e le meraviglie delle scienze naturali
No full textVengono trattate le ragioni che hanno indotto l'allestimento di una esposizione temporanea su Darwin a Modena e le riflessioni scientifiche e culturali che hanno guidato la scelta dei contenut
Phylogenetic relationships in the Macrobiotidae (Tardigrada : Eutardigrada : Parachela)
No full textCharacters of the claws, buccal-pharyngeal apparatus and ultrastructure of the cuticle have been examined to identify phyletic relationships within the Macrobiotidae. Several apomorphies have been identified. The resulting cladogram shows two main phyletic lines within the family, corresponding to the subfamilies Macrobiotinae and Murrayinae. The relationships among the genera of the Murrayinae are resolved, whereas in the Macro biotinae five main phyletic lines are identified, whose relationships are still unknown. Pseudodiphascon and Macrobiotus appear to be polyphyletic genera
The Tardigrades of Emilia (Italy). III. Piane di Mocogno (Northern Apennines).
No full textSamples of leaf litter, mosses and lichens were collected in a beech forest at Piane di Mocogno (Emilia, Italy), 1200 m asl. The tardigrade community of the leaf litter was similar to that found in this substrate in Italy and in the U.S.A. At Piane di Mocogno the species association within the leaf litter was different from that in mosses and lichens (which have similar fauna), confirming that very different communities characterise different substrates such as leaf litter and mosses. During this faunal analysis, six species of tardigrades were found for the first time in this area. The presence of Microhypsibius bertolanii (first record in leaf litter and in Italy) and Eohypsibius nadjae are note worthy. Ornamented eggs in an exuvium of Hypsibius cf. scabropygus were also recorded for the first time
Osservare gli animali per capire l'evoluzione: scelte tematiche ed espositive all'interno della mostra "Darwin: Modena e 200 anni di evoluzione"
No full textVengono discusse le tematiche ed espositive effettuate nella trattazione di tematiche biologiche e evolutive all'interno della mostra "Darwin: Modena e 200 anni di evoluzione
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