A paleoisthmus linking southern South America with the Antarctic Peninsula during Late Cretaceous and Early Tertiary

1998 ◽  
Vol 41 (3) ◽  
pp. 225-229 ◽  
Author(s):  
Shen Yanbin
Keyword(s):  
South America ◽  
Antarctic Peninsula ◽  
Late Cretaceous ◽  
Southern South America ◽  
Early Tertiary ◽  
The Antarctic

The santonian through paleogene record of Proteaceae in the southern South America - Antarctic peninsula region

1998 ◽  
Vol 11 (4) ◽  
pp. 373 ◽  
Author(s):  
Rosemary A. Askin ◽  
Alicia M. Baldoni
Keyword(s):  
South America ◽  
Antarctic Peninsula ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Type Species ◽  
Pollen Record ◽  
South American ◽  
Southern South America ◽  
Nothofagus Forest ◽  
The Antarctic

Proteaceous plants were an important component of the high-latitude Late Cretaceous–Paleogene podocarpaceous conifer and Nothofagus forest vegetation growing in high-rainfall temperate conditions. In the southern South America–Antarctic Peninsula region the fossil record of the Proteaceae comprises pollen, leaves, fruits and wood with affinities to the extant subfamilies Grevilleoideae, Proteoideae, and possibly Carnarvonioideae and Persoonioideae. The oldest reported occurrences of Proteaceae in this region are in the middle–late Santonian of the Antarctic Peninsula and include pollen of Proteacidites subscabratus Couper, with the addition in the Campanian of other species of Proteacidites and Propylipollis, Cranwellipollis spp. and Peninsulapollis spp. Diversity of proteaceous pollen increased through the Campanian and Maastrichtian, reflecting the spread of Proteaceae along the Antarctic Peninsula and into South America. Both endemic species and species derived from the Australian region are represented. Compared to coeval Australian assemblages, however, proteaceous diversity remained relatively low. Interestingly, Beauprea-type species (Beaupreaidites spp., Peninsulapollis spp.) are common and varied in the Antarctic Peninsula from Campanian into the Eocene, yet the South American pollen record does not include these forms, except for rare Peninsulapollis gillii. Possibly drier conditions may have discouraged northward migration of this group. South American fossil proteaceous taxa are primarily related to Grevilleoideae, a trend that continues into the modern flora on that continent.

The genus Struthiochenopus (Gastropoda, Aporrhaidae): new Miocene records from southern Chile

2014 ◽  
Vol 88 (1) ◽  
pp. 152-159 ◽  
Author(s):  
Sven N. Nielsen ◽  
Alfonso Encinas
Keyword(s):  
New Species ◽  
South America ◽  
Antarctic Peninsula ◽  
Late Cretaceous ◽  
Early Miocene ◽  
Southern Chile ◽  
Southern South America ◽  
Marine Gastropod ◽  
The Antarctic

The marine gastropod genus Struthiochenopus appears first in the late Cretaceous of the Antarctic Peninsula. Until the Oligocene only one or two species were extant at the same time. This changed drastically in the early Miocene when at least three species were living coevally in southern South America. A possible fourth early Miocene species, Struthiochenopus sp., is known from Ipún Island, Chile, but its identification remains unclear. Another taxon, S. echtleri new species, described from Neogene deposits of Mocha Island, Chile, has no precise age available but it is likely the latest survivor of the genus.

New trigonioid bivalves from the Albian (Early Cretaceous) of Alexander Island, Antarctic Peninsula: systematics, paleoecology, and austral Cretaceous Paleobiogeography

1995 ◽  
Vol 69 (2) ◽  
pp. 264-279 ◽  
Author(s):  
Simon R. A. Kelly
Keyword(s):  
South America ◽  
East Africa ◽  
Antarctic Peninsula ◽  
Early Cretaceous ◽  
Southern South America ◽  
The Antarctic ◽  
Molluscan Assemblage ◽  
Faunal Similarity

Newly discovered trigonioid bivalves are systematically described from the Late Albian of the Fossil Bluff Group of Alexander Island, Antarctic Peninsula. The fauna includes Nototrigonia (Nototrigonia) ponticula Skwarko, N. (Callitrigonia) offsetensis n. sp., Eselaevitrigonia macdonaldi n. sp., Pterotrigonia (Pisotrigonia) capricornia (Skwarko), and Pacitrigonia praenuntians n. sp. It represents the first Albian trigonioid fauna described from the Antarctic. It is also the first published record of the Nototrigoniinae (excluding Pacitrigonia) outside Australasia. Paleoecologically, this fauna represents the shallowest and highest energy molluscan assemblage from the Fossil Bluff Group and occurs near the base of a significant transgressive unit, the Mars Glacier Member of the Neptune Glacier Formation. The paleogeography of Austral Cretaceous trigonioids is reviewed. Endemic centers are identified in India–east Africa, southern South America, and Australasia. Only one trigonioid genus, Pacitrigonia, had its origin in the Antarctic. During the earliest Cretaceous, cosmopolitan trigonioid genera occurred in Antarctica. In the mid-Cretaceous faunal similarity of Antarctica with Australasia was strong, and in the latest Cretaceous affinity with southern South America increased.

Monimiaceae sensu lato, an element of Gondwanan polar forests: Evidence from the late Cretaceous-early tertiary wood flora of Antarctica

2001 ◽  
Vol 14 (2) ◽  
pp. 207 ◽  
Author(s):  
Imogen Poole ◽  
Helmut Gottwald
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
First Record ◽  
Southern South America ◽  
Anatomical Features ◽  
Early Tertiary ◽  
Breadth Ratio ◽  
Ecological Dominance ◽  
Perforation Plates ◽  
The Antarctic

Palaeofloristic studies of the Antarctic Peninsula region are important in furthering our understanding of (i) the radiation and rise to ecological dominance of the angiosperms in the Southern Hemisphere during the Late Cretaceous and (ii) the present day disjunct austral vegetation. Investigations of Upper Cretaceous and Early Tertiary sediments of this region yield a rich assemblage of well-preserved fossil dicotyledonous angiosperm wood which provides evidence for the existence, since the Late Cretaceous, of temperate forests similar in composition to those found in present-day southern South America, New Zealand and Australia. This paper describes two previously unrecognised morphotypes, which can be assigned to the Monimiaceae sensu lato, and represents the first record of this family in the wood flora of Antarctica. Specimens belonging to the first fossil morphotype have been assigned to Hedycaryoxylon SÜss (subfamily Monimioideae) because they exhibit anatomical features characteristic of Hedycaryoxylon and extant Hedycarya J.R.Forst. &amp; G.Forst. and Tambourissa Sonn. Characters include diffuse porosity, vessels which are mainly solitary with scalariform perforation plates, opposite to scalariform intervascular pitting, paratracheal parenchyma, septate fibres and tall (>3 mm), wide multiseriate rays with a length: breadth ratio of approximately 1: 4. Specimens belonging to the second morphotype have been assigned to Atherospermoxylon KrÄusel, erected for fossil woods of the Monimiaceae in the tribe Atherospermeae (now Atherospermataceae) in that they exhibit anatomical features similar to Atherospermoxylon and extant Daphnandra Benth., Doryphora Endl. and Laurelia novae-zelandiae A.Cunn. These characters include diffuse to semi-ring porosity, scalariform perforation plates with up to 25 bars, septate fibres, relatively short (<1 mm) rays with a length: breadth ratio of between 1: 4 and 1: 11.

Late Cretaceous and Tertiary aporrhaid gastropods from the southern rim of the Pacific Ocean

1995 ◽  
Vol 69 (4) ◽  
pp. 692-702 ◽  
Author(s):  
William J. Zinsmeister ◽  
Miguel Griffin
Keyword(s):  
New Species ◽  
New Zealand ◽  
South America ◽  
Late Cretaceous ◽  
Late Eocene ◽  
Southern South America ◽  
Early Tertiary ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Early Cenozoic

The new subfamily Struthiopterinae is proposed for the aporrhaid gastropods occurring in the Late Cretaceous-early Tertiary Weddellian Province along the southern margin of the Pacific. The following genera are placed within the Struthiopterinae: Struthioptera Finlay and Marwick, 1937; Austroaporrhais n. gen.; and Struthiochenopus n. gen. The temporal and biogeographic distribution of members of Struthiopterinae show a similar pattern to other Southern Hemisphere groups of Late Cretaceous and early Cenozoic molluscs with initial disappearance from the western Australasia of the Weddellian Province by the Paleocene while surviving in Antarctica until the late Eocene and eventually disappearing in southern South America during the early Miocene.Also included in this paper is a reappraisal of the species assignable to these genera from Late Cretaceous and early Tertiary of New Zealand, Antarctica, and southern South America together with the description of five new species. The following new species of the Struthiopterinae are described: Austroaporrhais larseni n. sp., A. stilwelli n. sp., A. dorotensis n. sp., Struthiochenopus antarcticus n. sp., and S. philippii n. sp.

Sarcopeltis gen. nov. (Gigartinaceae, Rhodophyta), with S. skottsbergii comb. nov. from southern South America and S. antarctica sp. nov. from the Antarctic Peninsula

Phytotaxa ◽  
2020 ◽  
Vol 468 (1) ◽  
pp. 75-88
Author(s):  
JEFFERY R. HUGHEY ◽  
GEOFFREY L. LEISTER ◽  
PAUL W. GABRIELSON ◽  
MAX H. HOMMERSAND
Keyword(s):  
South America ◽  
Antarctic Peninsula ◽  
Dna Sequences ◽  
Phylogenetic Analyses ◽  
New Genus And Species ◽  
Southern South America ◽  
Complete Mitogenome ◽  
Next Generation Sequencing Ngs ◽  
The Antarctic ◽  
Generation Sequencing

Gigartina skottsbergii is the currently accepted name for the large, peltate species of Gigartinaceae distributed in Argentina, Chile, and along the Antarctic Peninsula. However, phylogenetic analyses of DNA sequences for more than twenty years indicate that two species are passing under the name G. skottsbergii, and both DNA sequences and morpho-anatomy indicate that the species are assignable to an undescribed genus. To formally validate the new genus and species, we performed next generation sequencing (NGS) on the lectotype material of G. skottsbergii to document its genetic identity and obtained its complete mitogenome and partial plastid genome. Phylogenetic analysis of rbcL and cox1 sequences of the lectotype along with recent collections of G. skottsbergii from southern South America and Antarctica, confirmed the generic distinction and the presence of two morphologically similar taxa. We propose Sarcopeltis gen. nov., containing the generitype S. skottsbergii comb. nov. from southern South America, and S. antarctica sp. nov. from the Antarctic Peninsula. Sarcopeltis is characterized by the following suite of features: 1) peg-like secondary haptera that adhere to the substratum, 2) absence of an envelope surrounding each cystocarp, 3) presence of extensive, terminal, tubular gonimoblast filaments that fuse with surrounding vegetative cells, and 4) tetrasporangia formed from secondary filaments entirely in the medulla. This study demonstrates that genetic analysis of type material, together with recently obtained DNA sequences from field collected specimens, can provide clear and objective taxonomic conclusions.

A unifying lithostratigraphy of late Cretaceous–early Tertiary fore-arc volcanic sequences on Alexander Island, Antarctica

1997 ◽  
Vol 9 (2) ◽  
pp. 209-220 ◽  
Author(s):  
Joe J. McCarron
Keyword(s):  
Antarctic Peninsula ◽  
Late Cretaceous ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Magmatic Arc ◽  
Ridge Subduction ◽  
Volcanic Group ◽  
Early Tertiary ◽  
Plutonic Rocks ◽  
The Antarctic

Late Cretaceous–early Tertiary subduction-related fore-arc volcanic rocks are exposed in a north–south linear belt along the length of Alexander Island. The age and tectonic setting of these rocks is well understood; they are not considered to represent “normal” arc magmas but were generated in the fore-arc as a result of ridge subduction. Due to their distinct composition and mode of formation, they are no longer considered to be genetically related to the Antarctic Peninsula magmatic arc. They are therefore removed from the Antarctic Peninsula Volcanic Group and placed in a newly defined Alexander Island Volcanic Group. The group is made up of the Monteverdi, Staccato, Walton, Colbert, Elgar and Finlandia formations, which vary widely in lithology, facies and age. The Colbert and Elgar formations are subdivided into nine and three members respectively. Type localities, representative lithologies and age of each of the formations are discussed. The Staccato and Colbert Magmatic complexes are defined to include volcanic and plutonic rocks that are considered to be coeval. The Rouen Intrusive complex combines the plutonic rocks from the Rouen Mountains and Rothschild Island on the basis of age and chemistry.

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