1,721,125 research outputs found
Developmental vs genetic variation in two mediterranean rissoid gastropod complexes
No full textThe presence of either planktotrophic [P] or nonplanktotrophic [NP] larval development, can exert a remarkable influence on life history of species, especially as regards their dispersal capability, the possibility and the extent of gene flow between populations, as well as the extinction rate of the specie
The southernmost record of Felimida elegantula (Philippi, 1844) (Gastropoda: Nudibranchia)
Full text linkThe southernmost record of the Mediterranean nudibranch Felimida elegantula (Philippi, 1844) is reported here. A single specimen, with a colour pattern that hampered an easy morphological identification, was collected at the Kerkennah Islands (Tunisia). DNA-barcoding analysis (with the cytochrome c oxidase subunit I genetic marker) unambiguously confirmed its identification, and radular and anatomical features conformed with those previously described. With this record, the chromatic polymorphism of F. elegantula is demonstrated to be extremely large and the known range of the species is extended to the African coast of Tunisia
Molecular biogeography of the Mediterranean genera Podarcis and Teira (Reptilia, Lacertidae)
No full textDeep-water Rissoidae of the genera Benthonella Dall, 1889 and Benthonellania Lozouet, 1990 (Gastropoda, Caenogastropoda, Rissooidea) from French Polynesia
No full textShallow-water Rissoidae of the genera Alvania Risso, 1826, HaurakiaIredale, 1915, Parashiela Laseron, 1956, Simulamerelina Ponder, 1985 and Subestea Cotton, 1944 (Gastropoda, Caenogastropoda,Rissooidea) from French Polynesia, with the description of a new deep-water genus
No full textThe extant species of the genera Alvania Risso, 1826, Haurakia Iredale, 1915, Parashiela Laseron, 1956, Simulamerelina Ponder, 1985 and Subestea Cotton, 1944 (Rissoidae Gray, 1847) collected in the shallow waters of French Polynesia are herein revised, for a total of 19 species. Additionally, a new genus for a new deep-water species is here introduced. Two species with wide range in the Pacific are reported: Haurakia marmorata (Hedley, 1907) and Parashiela ambulata Laseron, 1956. Five species of Alvania, one of Ellenstrongia n. gen., five of Parashiela, six of Simulamerelina and one Subestea are described as new: Alvania letourneuxi n. sp., Alvania herosae n. sp., Alvania parvimaculata n. sp., Alvania prosocostata n. sp., Alvania uapou n. sp., Ellenstrongia tarasoc n. gen., n. sp., Parash- iela expansilabrum n. sp., Parashiela obesula n. sp., Parashiela rimatara n. sp., Parashiela rotundata n. sp., Parashiela soniae n. sp., Simulamerelina australes n. sp., Simulamerelina densestriata n. sp., Simulamerelina gracilis n. sp., Simulamerelina lepteseiras n. sp., Simulamerelina micrometrica n. sp., Simulamerelina tuamotu n. sp., Subestea moruroa n. sp. Three taxa are transferred to Alvania: Rissoa denseclathrata Thiele, 1925, Rissoa lusoria Yokoyama, 1926, Rissoa proditoris Thiele, 1925. Twelve species have a non-planktotrophic development; five of them are endemic to a single archipelago: Alvania letourneuxi n. sp., Simulamerelina gracilis n. sp., Simulamerelina tuamotu n. sp. to Tuamotu, Simulamerelina densestriata n. sp. to Australes, Parashiela soniae n. sp. to Marquesas. Of the eight spe- cies with planktotrophic development, two are apparently endemic to a single archipelago: Parashiela obesula n. sp. and Parashiela rimatara n. sp. to Australes
A new species of the genus Crisilla Monterosato, 1917 from the Mediterranean Sea (Gastropoda: Rissoidae)
No full textA new Mediterranean species of the genus Crisilla Monterosato, 1917 (Rissooidea, Rissoidae) is described:
Crisilla hiera n. sp. All known specimens are empty shells retrieved from a sample of bioclastic sand collected
in a submarine cave at Marettimo Island (type locality). It is compared with the most similar congeners
from the Mediterranean Sea, such as Crisilla beniamina (Monterosato 1884), C. aartseni (Verduin
1984), C. ramosorum Oliver, Templado & Kersting, 2012, C. didyme Amati & Oliverio, 2020 and Crisilla sp.
(Romani et al., 2018), and from the Eastern Atlantic Ocean, such as C. ugesae (Verduin, 1988) and C.
ugesae sensu Auctores. Crisilla didyme is first reported from a site different from the type locality, at Capo
Palinuro (southern Tyrrhenian Sea)
Structural and sequence evolution of U17 small nucleolar RNA (snoRNA) and its phylogenetic congruence in chelonians.
No full textVertebrate U17 RNA is an intron-encoded
H/CA box containing snoRNA, which has been intensively
studied in the last decade, though its precise
role in ribosome biogenesis is not yet clear. A consensus
secondary structure for the U17 RNA molecule
has been derived from the comparative sequence and
structural evolution analysis of U17 snoRNA among
vertebrates. Its phylogenetic congruence above class
level has been tested and preliminary data on chelonians
suggest that also in this order, U17 snoRNA
evolved congruently with phylogeny. We herein extend
our analysis to other components of this reptile
group. According to the sequence data that have also
emerged from chelonians, the U17 RNA molecule can
be divided into two main domains: the 50-variable
domain, which presents the sequence motifs capable
of base-pairing with the 18S rRNA target and spanning
STEM1, -2, and -3, and the 30-conserved domain,
consisting of STEM4. In vertebrates, the latter RNA
region shows a high conservation both in secondary
structure and in the presence of the three sequence
motifs 50-AUUCCUA-30, 50-U(G/U)ACU-30, and 50-
AACCC-30.We tested the phylogenetic congruence of
U17 evolution with chelonian relationships: Our
results are significantly similar to those emerging from
mtDNA and morphological systematics. Some discrepancies
(e.g., the position of Platysternon) need to
be addressed in greater depth
Educazione come paideía? Il misreading deweyano del mito platonico della caverna.
No full textIl capitolo sviluppa un'interpretazione dell'idea deweyana di educazione come una mis-lettura della nozione platonica di paideia. In particolare, si argomenta che la problematica deweyana si inserisce nella radiazione di quel big-bang filosofico-paidetico di cui il documento più insigne è il testo de Le Nuvole di Aristofane (nonché l'ambivalente relazione di Platone con tale opera)
- …
