| 1. |
- Bremer, Oskar, 1985-, et al.
(författare)
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Vertebrate microremains from the upper Silurian Winnica Formation of the Holy Cross Mountains, Poland
- 2018
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Ingår i: Geological Magazine. - 0016-7568 .- 1469-5081. ; 155:7, s. 1523-1541
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Tidskriftsartikel (refereegranskat)abstract
- Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Poland are described from the Winnica and Rzepin sections. Both sites record the uppermost part of the Supianka Member, but represent different depositional environments. The Winnica samples come from a low-energy environment, while the Rzepin sample was taken from a high-energy, oolitic facies. Both sites contain thelodonts Thelodus parvidens, Thelodus trilobatus, an anaspid cf. Liivilepis and a number of acanthodian scales of 'nostolepid', poracanthodid and 'gomphonchid' types. Notable differences between the sites are the addition of the osteostracan Tahulaspis cf. ordinata, the thelodont Paralogania ludlowiensis and acanthodian scales identified as Nostolepis gracilis in the Rzepin section. Placing the vertebrate faunas within the vertebrate biozonation established for the Silurian proved difficult. The suggested late Ludlow age for the Supianka Member based on sequence stratigraphical and chemostratigraphical correlations cannot be definitely confirmed or refuted, but a late Ludfordian age seems the most plausible based on invertebrate and vertebrate faunas. The much lower abundance of poracanthodid acanthodians in the Rzepin sample supports the notion of Poracanthodes porosus Zone as a deep-water equivalent to a number of vertebrate biozones. The presence of P. ludlowiensis only in the oolitic sample confirms a long temporal range, but restricted environmental distribution for this taxon.
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| 2. |
- Niedzwiedzki, Grzegorz, 1980-, et al.
(författare)
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A new occurrence of the Late Triassic archosaur Smok in southern Poland
- 2018
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Ingår i: Acta Palaeontologica Polonica. - : INST PALEOBIOLOGII PAN. - 0567-7920 .- 1732-2421. ; 63:4, s. 703-712
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Tidskriftsartikel (refereegranskat)abstract
- Two isolated teeth, a dorsal vertebra, fragments of a humerus and femur, a fragmentary pubic "boot" and part of an ischium shaft, identified here as belonging to a large predatory archosaur were discovered in the Upper Triassic site at Marciszow near Zawiercie (southern Poland). Comparisons of the new fossils from Marciszow with the dorsal vertebrae, pubic "boot", ischium and femur of the theropod-like Smok wawelski from Lisowice (Silesia) reveal that the two taxa are very similar. Nevertheless, due to the lack of more diagnostic elements (e.g., braincase or cranial elements), we prefer to consider all described specimens from Marciszow as Smok sp. Smok sp. shares a low mound-like, anterior trochanter with trochanteric shelf on the femur, a massive pubic "boot" with a distinct depression (= bevelled area), and a transversely lenticular ischium shaft in cross-section with S. wawelski. Some observed characters of the dorsal vertebra (e.g., lack of some lamina, shape and position of zygapophyses), however, are different from S. wawelski and may also suggest that the new findings represent a second species of the genus in the Upper Triassic of Poland. The discovery of Smok sp. at Marciszow is significant because it is the second example of the co-occurrence of this genus with: (i) bones of a large dicynodont; and (ii) record of gnawed tetrapod bones. The discovery of Smok sp. and the lack of significant morphologic divergence from S. wawelski suggest that this taxon is the only large-bodied predator currently known from the Upper Triassic of Poland. This new evidence expands the record of the genus and contributes, in some measure, to our knowledge of the stratigraphical distribution of large predatory archosaurs from the Polish Upper Triassic bone-bearing levels.
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| 3. |
- Qvarnström, Martin, et al.
(författare)
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A new charophyte flora from the Upper Triassic of Skane (Sweden) and implications on biostratigraphy, taphonomy and the palaeoenvironment
- 2018
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Ingår i: Review of Palaeobotany and Palynology. - : Elsevier. - 0034-6667 .- 1879-0615. ; 249, s. 61-79
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Tidskriftsartikel (refereegranskat)abstract
- The record of fossil charophytes from Sweden was previously restricted to the Ladinian-earliest Carnian Falsterbo Formation. Here, we present a charophyte assemblage from the Upper Triassic KAgerod Formation exposed at the Balteberga Gorge (Sickle, southern Sweden) from the perspectives of taxonomy, taphonomy, palaeoecology and biostratigraphy. The microfossils originate from an interval of reddish sandy mudstone and are represented by rare fossil thalli, calcium carbonate encrustations of thalli and numerous calcified fructifications, called gyrogonites. The assemblage is relatively diverse, comprising six species belonging to four genera of the family Porocharaceae (Auerbachichara cf. rhaetica, Porochara sp., Stellatochara germanica, Stellatochara aff. subsphaerica, Stenochara aff. donetziana, Stenochara aff. kisielevskyi). Both the sedimentological context and the preservation of the charophyte remains point to an autochthonous origin for the charophyte-bearing strata. An autochthonous origin together with the habitat of modern charophytes, infer that the charophyte interval was deposited in shallow ephemeral pond or lake in a terrestrial setting. Their occurrence is also indicative of low amount of nutrients and the numerous thalli encrustations suggest a rather alkaline water composition. Some of the described species (Auerbachichara cf. rhaetica and Stellatochara aff. subsphaerica) are useful for biostratigraphical correlations which attributes the assemblage to the Auerbachichara rhaetica Range zone (sensu Bilan, 1991) in the proposed Germanic Triassic charophyte zonation. This range zone is assigned to a latest Carnian to late Norian age, strengthened by an interlayering with rocks containing a characteristic assemblage of palynomorphs (Corollina meyeriana subzone a and b) in the Upper Triassic of the Polish part of the Germanic Basin. The findings of the first Triassic thalli further strengthen the suggestion that the early Mesozoic fossil record of charophytes is not solely composed of oospores and gyrogonites. A better understanding of vegetative fossil remains (silicified thalli and encrustations) of charophytes may provide important future palaeoecological implications and links between recent and extinct forms. Our findings also provide evidence that charophyte occurrences in the ICagerod Formation are strictly controlled by palaeoenvironmental factors. (C) 2017 Elsevier B.V. All rights reserved.
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| 4. |
- Qvarnström, Martin, et al.
(författare)
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Non-marine palaeoenvironment associated to the earliest tetrapod tracks
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Opinions differ on whether the evolution of tetrapods (limbed vertebrates) from lobe-finned fishes was directly linked to terrestrialization. The earliest known tetrapod fossils, from the Middle Devonian (approximately 390 million years old) of Zachelmie Quarry in Poland, are trackways made by limbs with digits; they document a direct environmental association and thus have the potential to help answer this question. However, the tetrapod identity of the tracks has recently been challenged, despite their well-preserved morphology, on account of their great age and supposedly shallow marine (intertidal or lagoonal) depositional environment. Here we present a new palaeoenvironmental interpretation of the track-bearing interval from Zachelmie, showing that it represents a succession of ephemeral lakes with a restricted and non-marine biota, rather than a marginal marine environment as originally thought. This context suggests that the trackmaker was capable of terrestrial locomotion, consistent with the appendage morphology recorded by the footprints, and thus provides additional support for a tetrapod identification.
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| 5. |
- Skrzycki, Piotr, et al.
(författare)
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Dipnoan remains from the Lower-Middle Triassic of the Holy Cross Mountains and northeastern Poland, with remarks on dipnoan palaeobiogeography
- 2018
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 496, s. 332-345
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Tidskriftsartikel (refereegranskat)abstract
- Here we present a revision of dipnoans from the Middle-Upper Buntsandstein and the Lower Muschelkalk (Lower-Middle Triassic) of the Holy Cross Mountains (southeastern Poland) and from the Middle Buntsandstein of northeastern Poland. Two genera are identified: Arganodus and Ptychoceratodus. Specimens resemble synchronous species from the European part of Russia. It is the first Middle Triassic finding of Arganodus worldwide. Ptychoceratodus is reported for the first time from the Lower Triassic of Poland. It is its oldest known occurrence in Europe. The Holy Cross Mountains stands between the area of European Russia and the Central European Basin which were both inhabited by Arganodus and Ptychoceratodus in the Early-Middle Triassic. Resulting from a summary of palaeobiogeographic data of these two genera their distributional patterns are hypothesized herein. In the Early Triassic both genera often co-occurred in many regions. Starting from the Middle Triassic their ranges split into two almost separate ones. They reflect the palaeolatitudinal belts in the Late Triassic with Arganodus in the northern tropic belt and Ptychoceratodus along the palaeolatitudes 30 degrees.
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| 6. |
- Zaton, Michal, et al.
(författare)
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Earliest Triassic metazoan bioconstructions from East Greenland reveal a pioneering benthic community in the immediate aftermath of the end-Permian mass extinction
- 2018
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Ingår i: Global and Planetary Change. - : ELSEVIER SCIENCE BV. - 0921-8181 .- 1872-6364. ; 167, s. 87-98
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Tidskriftsartikel (refereegranskat)abstract
- Marine benthic ecosystems collapsed during the catastrophic end-Permian mass extinction, and subsequently endured a protracted phase of biotic recovery under harsh environmental conditions. In particular, metazoan reef communities almost totally disappeared and were replaced by microbe-dominated mounds during the latest Permian-earliest Triassic. Here we report the stratigraphically oldest exclusively metazoan bioconstructions from earliest Triassic (mid-Induan) strata in East Greenland - these formed within the first ca 300 ka after the Permian-Triassic boundary. Unlike the multitaxic sponge-microbe and bivalve-based buildups recorded from the Early Triassic peri-paleoequatorial Panthalassan and Tethyan margins, the East Greenland bioaccumulations developed within a restricted Boreal mid-paleolatitude seaway, and comprised a monospecific primary framework of microconchid 'lophophorate tubes with shell fragments and phosphatic debris cemented by biogenic calcite. Prostrate growth of the microconchids likely facilitated their accretion into successive sheet-like biostromes and small bioherms. These are associated with a regional paleoenvironmental shift towards well-oxygenated bottom waters, and locally punctuated sedimentation that created a favorable habitat. Although microconchids were both abundant and geographically widespread throughout the earliest Triassic, such buildups formed solely by these metazoans have not been reported from that time frame outside the Boreal Realm. These apparently flourished in the absence of more stable complex communities, and suggest that a locally variable, rather than ubiquitously sequential revival of metazoan bioconstruction activity took place in the immediate aftermath of the end-Permian extinction. However, these may also suggest that ecological recovery of benthic marine ecosystems following the end-Permian mass extinction might have started earlier in higher paleolatitudes.
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