 Subjects -> PALEONTOLOGY (Total: 43 journals)
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- UPPER PENNSYLVANIAN AGE OF THE LOWER TALCHIR FORMATION IN THE WARDHA
BASIN, CENTRAL INDIA, BASED ON GUIDE PALYNOMORPHS PRESENT IN
RADIOMETRICALLY- DATED PALYNOZONATIONS IN SOUTH AMERICA, AFRICA, AND
AUSTRALIA
Authors: Pauline S. Kavali, Anirban Roy, Mercedes di Pasquo, Gundiga P. Gurumurthy, Gaurav Sharma, Ajit Kumar
Abstract: This addendum is published to validate the proposed combination in Ameghiniana 58(4):326 following Art. 41.5 of the International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code, Turland et al., 2018)). The new combination Cristatisporites conatus was first proposed by Kavali et al. (2021) but was not validly published as it was introduced without the full and direct reference (with page or plate) of the basionym.
PubDate: 2022-03-15
Issue No: Vol. 59, No. 2 (2022)
- PALEOENVIRONMENTAL RELEVANCE OF AMORPHOUS SILICA MICROFOSSILS IN
HYDROMORPHIC PALEOSOLS, A COMPARATIVE STUDY WITH MODERN ANALOGOUS
ENVIRONMENTS IN THE SOUTHERN PAMPAS, ARGENTINA
Authors: Roberto Donna, Gabriela S. Hassan, Margarita Osterrieth
Pages: 127 - 140
Abstract: In this contribution we describe assemblages of amorphous silica microfossils in a hydromorphic paleosol for the first time in the Southern Pampas. And through a comparative analysis with modern shallow lakes, we discuss their relevance and biases as paleoenvironmental indicators. The hydromorphic paleosol analyzed is exposed in the Barranca de Los Lobos section, located in the Atlantic coast of the Buenos Aires province (Argentina), and was placed around the Pliocene/Pleistocene boundary by magnetostratigraphy studies. Of all amorphous silica microfossils, silicophytoliths were the only well represented in both the hydromorphic paleosol and modern environments, which allowed a comparative analysis of assemblages based in the relative abundance of morphotypes and a paleoclimatic reconstruction. Other amorphous silica microfossils were found in low abundances and poor preservation states in the hydromorphic paleosol, which did not allow quantitative analyses. Two types of chrysophycean cysts were identified, being Clericia spinigera also present in the modern environments studied. Diatom fragments found in the hydromorphic paleosol were unidentifiable. Whereas in the modern shallow lakes, 35 species were recognized, which allowed the delimitation of diatom zones and the differentiation of deepening and drying periods in recent history. Spicules of freshwater sponges were found fragmented as a trace component in both the paleosol and modern shallow lakes, suggesting an allochthonous origin. Our results provide new insights on the paleoenvironmental evolution of the region, and highlight the potential use of amorphous silica microfossils as bioindicators in paleosols of the Late Cenozoic pedosedimentary sequences of the Southern Pampas.
PubDate: 2022-03-15
DOI: 10.5710/AMGH.16.10.2021.3461
Issue No: Vol. 59, No. 2 (2022)
- RE-EVALUATING CRANIAL PATHWAYS OF THE INTERNAL CAROTID ARTERY IN
NOTOUNGULATA (MAMMALIA, PANPERISSODACTYLA)
Authors: Ross D. E. MacPhee, Analía M. Forasiepi
Pages: 141 - 161
Abstract: On the basis of selected osteological markers, Patterson (1936) identified two pathways (here designated A and B) along which the internal carotid artery in notoungulates was said to travel in order to enter the skull and supply the brain. The existence of these pathways, at least as Patterson defined them, has been disputed but no substantive alternatives have been proposed. Using comparative embryological and morphological evidence based on conditions in extant mammals, we find that pathway A (intratympanic) is not supported. Pathway B (enclosed extratympanic) is supportable, but as far as is now known applies only to a small number of notoungulate taxa. On the basis of new evidence, we propose another route, pathway C, briefly mentioned by Scott (1912) but subsequently ignored, that may apply to the majority of notoungulates. In pathway C (unenclosed extratympanic) the internal carotid passed directly into the endocranium via a naturally unossified area of the basicranium, the piriform fenestra, rather than coursing through or alongside the middle ear in a canal. The absence of a separate, bony carotid foramen on the basicranium’s ventral surface may explain the hesitancy of previous workers to consider this routing. There is no evidence that the function of the internal carotid artery was supplanted by another vessel (e.g., external carotid artery) in any notoungulate. Conditions in other major clades of South American native ungulates are poorly investigated, but some clearly differed from notoungulates in carotid patterning, pointing to the existence of substantial intertaxon disparities.
PubDate: 2022-03-15
DOI: 10.5710/AMGH.06.12.2021.3465
Issue No: Vol. 59, No. 2 (2022)
- BRYOZOANS ASSOCIATED WITH GASTROPOD SHELLS IN THE EARLY MIOCENE OF
PATAGONIA (ARGENTINA)
Authors: Leandro M. Pérez, Juan López-Gappa
Pages: 162 - 170
Abstract: This study describes two new species of cheilostome bryozoans associated with gastropod shells from the Monte León Formation (Burdigalian, early Miocene), Argentine Patagonia. Burdwoodipora griffini sp. nov. is the second known species and the first fossil representative of the genus, whose geographic distribution is so far restricted to the Magellan region in the southern Southwest Atlantic. It differs from the type species, B. paguricola, in lacking suboral adventitious avicularia in most autozooids. Odontoporella miocenica sp. nov. is morphologically very close to the type species, the Recent O. adpressa, from which it differs in having smaller zooids with fewer areolae and relatively wider orifices. The stratigraphic range of Odontoporella is here extended from the Pleistocene to the early Miocene. Its geographic distribution includes southern South America, New Zealand, and New Caledonia, suggesting an austral origin of the genus in the Paleogene of former Gondwana. The possible association of these two species with paguroid crabs is discussed.
PubDate: 2022-03-15
DOI: 10.5710/AMGH.27.01.2022.3485
Issue No: Vol. 59, No. 2 (2022)
- THE ORIGIN OF SNAKES: MORPHOLOGY AND THE FOSSIL RECORD (1ST EDITION)
Authors: Fernando Fabio Garberoglio
Pages: 171 - 173
PubDate: 2022-03-15
Issue No: Vol. 59, No. 2 (2022)
- COCCOLITHOPHORES: CENOZOIC DISCOASTERALES - BIOLOGY, TAXONOMY,
STRATIGRAPHY
Authors: Juan Pablo Pérez Panera
Pages: 174 - 176
PubDate: 2022-03-15
Issue No: Vol. 59, No. 2 (2022)
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