Aim We investigated the phylogeography, geographical variation in leaf morphology, freezing tolerance and climatic niches of two widespread evergreen sister oak species (Quercus) in the series ...Virentes. Location South-eastern USA, Mexico and Central America. Methods Nuclear microsatellites and non-recombining nuclear and chloroplast DNA sequences were obtained from trees throughout the range of two sister lineages of live oaks, represented by Quercus virginiana in the temperate zone and Q. oleoides in the tropics. Divergence times were estimated for the two major geographical and genetic breaks. Differentiation in leaf morphology, analysed from field specimens, was compared with the molecular data. Freezing sensitivities of Q. virginiana and Q. oleoides populations were assessed in common garden experiments. Results The geographical break between Q. virginiana and Q. oleoides was associated with strong genetic differentiation of possible early Pleistocene origin and with differentiation in freezing sensitivity, climatic envelopes and leaf morphology. A second important geographical and genetic break within Q. oleoides between Costa Rica and the rest of Central America showed a mid-Pleistocene divergence time and no differentiation in leaf morphology. Population genetic differentiation was greater but genetic diversity was lower within the temperate Q. virginiana than within the tropical Q. oleoides, and genetic breaks largely corresponded to breaks in leaf morphology. Main conclusions Two major breaks, one between Mexico and the USA at the boundary of the two species, and a more recent one within Q. oleoides between Honduras and Costa Rica, implicate climatic changes as potential causes. The latter break may be associated with the formation of the Cordillera de Guanacaste, which was followed by seasonal changes in precipitation. In the former case, an ‘out of the tropics' scenario is hypothesized, in which the acquisition of freezing tolerance in Q. virginiana permitted colonization of and expansion in the temperate zone, while differences in climatic tolerances between the species limited secondary contact. More pronounced Pleistocene changes in climate and sea level in the south-eastern USA relative to coastal Mexico and Central America may explain the greater population differentiation within temperate Q. virginiana and greater genetic diversity in tropical Q. oleoides. These patterns are predicted to hold for other taxa that span temperate and tropical zones of North and Central America.
The history of discovery and study of the unique mummified brain of the 39 thousand cal. BP woolly mammoth fossil from Yakutian permafrost with special references to the big brain reconstruction ...method is provided. The preliminary description of the reconstracted gyri and sulci is described and paleoneurological perspectives are observed and discussed. The big brain of the woolly mammoth demonstrates the complicated patterns of the primary, seconds and tertiary gyrification, which could be potentially used for the comparative study of the extinct mammoth specimen and living representatives of Elephantidae and for searching cross-genus differences.
Recent study of the small mammals (rodents and insectivores) from several fossil-bearing sites situated in the central sector of the Guadix Basin (Southern Spain) has notably increased the knowledge ...of the mammal assemblages that existed in Southern Iberia from the latest Miocene to the earliest Pleistocene. On the basis of this new information, we propose a biozonation for the continental deposits of the Guadix Basin, which consists of six biozones ranging in age from the late Turolian (MN13) to the early Villanyian (MN17). These biozones, defined according to the rules of the International Stratigraphical Guide, include not only the mentioned recently discovered fossil sites, but also other, previously known, localities of the basin. Finally, we integrate the described biozones in the Neogene Mammal units and the European Land Mammal Ages, correlate them with several classical mammal sites from other Iberian basins and the rest of Europe, and establish an approximate numerical age for the lower and upper limits of each biozone.
Gorski masiv Stare Galičice je bil v pleistocenu izrazito preoblikovan z ledeniškim delova-njem. Na podlagi detajlnega morfografskega kartiranja ledeniških oblik je bil določen ob-seg poledenitve, ki ...je bil veliko večji kot ga navaja predhodna literatura. Osrednji del gor-skega masiva je prekrival ledeni pokrov, od katerega so navzdol odtekali odtočni ledeniki. Na podlagi morfometričnih analiz sledov poledenitve je bila ugotovljena ravnovesna meja viška zadnje poledenitve na nadmorski višini 1840 m.
Ribe so gotovo pomenile vsaj majhen delež v prehrani ljudi, ki so prebivali na osrednjem slovenskem ozemlju. To dokazujejo tudi najdbe njihovih ostankov iz pleistocenskih in holocenskih (kvartarnih) ...plasti nekaterih arheoloških in paleontoloških najdišč. Zelo malo prispevkov obravnava kvartarne ostanke rib, še manj jih te tudi slikovno prikazuje in opredeljuje. V prispevku želimo prikazati najdbe, ki so shranjene v paleontoloških zbirkah Prirodoslovnega muzeja Slovenije in prihajajo z najdišč na Ljubljanskem barju (Opekarna pri Vrhniki, Breg pri Škofljici, Dežmanova kolišča pri Igu) in iz Križne jame na Notranjskem. Na osnovi ostankov smo iz pleistocenskih glin pri Vrhniki določili ostanke ščuke (Esox lucius). Z mezolitskega najdišča Breg pri Škofljici smo določili ostanke ščuke (Esox lucius), soma (Silurus glanis) in smuča (Sander lucioperca). Iz bakreno- in bronastodobnih (holocenskih) plasti na Ljubljanskem barju (Dežmanova kolišča pri Igu) smo določili ostanke ščuke (Esox lucius). Najbolj enigmatični pa so ostanki krapa (Cyprinus carpio) iz Križne jame, saj gre za nenavadno najdišče rib. Verjetno jih lahko povežemo z obiski ljudi v bronasti dobi ali še mlajših obdobjih.
Pleistocenska poledenitev Biokova Žebre, Manja; Stepišnik, Uroš
Dela (Univerza v Ljubljani. Oddelek za geografijo),
12/2013
39
Journal Article
Recenzirano
Odprti dostop
Biokovo je gorski masiv v obalnem delu Dinarskega gorstva na Hrvaškem. S podrobno morfografsko in morfometrično analizo najvišjega dela gorskega masiva smo določili obseg in značilnosti ...mlajšepleistocenske poledenitve. Izdelali smo rekonstrukcijo topografije ledenikov in izračunali višino njihove ravnovesne meje. Ugotovili smo, da sta bila severovzhodno pod vrhom Sveti Jure dva krniška ledenika s skupno površino 1 km2, ravnovesna meja pa je bila na višini 1515 m.
Trnovski gozd je visoka kraška planota na dinarskem krasu zahodne Slovenije, ki so jo v pleistocenu preoblikovali tudi ledeniški procesi. Ugotovili smo, da je severna pobočja in podnožje najvišjega ...osrednjega grebena Golaki pokrival ledenik s površino 4,8 km2 in največjo debelino okoli 180 m. V več odtočnih ledenikih je padal preko strme reliefne stopnje v dolini Belce in Trebuše ter na Hudo polje. Prisojna pobočja Golakov niso bila poledenela. Z metodama deleža akumulacijskega dela ledenika ter zgornje meje bočnih moren smo izračunali ravnovesno mejo ledenikov na višini 1240 m.
U radu je prikazano istraživanje u podmorju sjevernog Jadrana i priobalja južne Dalmacije unutar naslaga pliocena, pleistocena i holocena. Njime su opisane postojeće litostratigrafske jedinice u ...taložinama rijeke Po u Hrvatskoj i određene takve jedinice u prostoru taloženja rijeke Neretve. Oba taložna prostora bila su pod utjecajem promjena razina mora, posebice tijekom kvartara, što se znatno odrazilo u smanjivanju dubine mora i povećanju površine kopna tijekom oledaba, posebice u sjevernom Jadranu. U hrvatskom dijelu Padske depresije navedene su dvije formacije – Istra (pliocen) i Ivana (pleistocen, holocen). U formaciji Ivana opisana su tri člana, poimence Anamarija, Katarina i Izabela. Dalje prema jugu, u priobalju južne Dalmacije, imenovana je nova formacija Neretvanski kanal (za taložine pliocena, pleistocena i holocena). Ona je zatim podijeljena u pijeske Neretva (koji mogu biti ekvivalent i cijele formacije) te član Malostonski zaljev (kvartarne starosti). Isključivo pliocenski tipski litotip nije opisan.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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