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(1) Valeria lophostriata, 76521-t32, 4. (2) Simia annulare, 76091-r27. (3) Pterospermopsimorpha insolita, 76091-v52. (4, 5) Germinosphaera bispinosa: (4) bearing one large process (76801-h28,4); (5) bearing two large processes (DLFC-25; SEM). (6) Osculosphaera hyalina, with a large pylome opening (excystment structure; arrow), 76801-s37,2. (7-9) Dictyosphaera macroreticulata: (7) 76092-n30,1 bearing a pylome opening (arrow); (8) 76567-f45; (9) 75514-o58. (10, 11), Satka favosa: (10) 76803-u34; (11) 76514-m45. (12-14) Spiromorpha segmentata: (12) 76091-j35; (13) 76522-f54, 4; (14) 76511-y41. All photomicrographs taken under transmitted, plane-polarized light. (1-7, 9-14) are from sample HB07-41A 183 m; (8) is from sample HB07-41A 232 m. Scale bar in (9) = 20 μm for (4, 5, 9-11, 13), 30 μm for (1-3, 6, 8, 12), 40 μm for (7), and 50 μm for (14).
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The Mesoproterozoic is an important era for the development of eukaryotic organisms in oceans. The earliest unambiguous eukaryotic microfossils are reported in late Paleoproterozoic shales from China and Australia. During the Mesoproterozoic, eukaryotes diversified in taxonomy, metabolism, and ecology, with the advent of eukaryotic photosynthesis,...
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... at least the entire Mesoproterozoic and probably into the early Neoproterozoic. Moczydłowska et al. (2011) andAgicétAgicét al. (2015) suggested that D. macoreticulata could have been a cyst, opening through an operculate pylome excystment structure, as previously observed by Yin et al. (2005). The specimen bearing a circular pylome reported here (Fig. 4.7) supports this suggestion, although no operculum is evidenced. The presence of this elaborate structure and the tessellated nature of the wall of D. macroreticulata indicate that it was unambiguously a member of the total group ...
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... Butterfield et al. (1994) emended the species to include specimens with one to four processes, distributed on the equatorial plan of the vesicle, and synonymized G. bispinosa and G. unispinosa into G. bispinosa (according to name priority). .-Specimen GINPC 14711-804 in Vorob'eva et al. (2015, fig. ...
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... Butterfield et al. (1994) Jankauskas et al. (1989) and were detected only in microfossils reported by Loron et al. (2019a). Loron and Moczydłowska (2018) erected the new species L. gorda on the basis of a smooth-walled specimen bearing a large, polygonal-shaped pylome opening. Only two specimens are illustrated, and one of them (pl. 2, fig. 4) might be modern contamination. They might constitute a distinct species of Osculosphaera, but this will require the observation of more convincing ...
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... genus Satka was originally divided into six species ( Jankauskas et al., 1989 Sakta favosa Jankauskas, 1979 Figure 4.10, 4.11 1979 Satka favosa Jankauskas, pl. 4, fig. 2. 1989 Satka favosa; Jankauskas et al., p. 51, pl. 4, figs. 1, 2? 1989 Satka elongata; Jankauskas et al., p. 51, pl. 4, figs. ...
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... Simia Mikhailova and Jankauskas in Jankauskas et al., 1989 Type species.-Simia simica (Jankauskas, 1980) Jankauskas, 1989. fig. 4G. 12.5. 2017 Simia annulare; AgicétAgicét al., p. 118, figs. 10FI, 14H, I. 2017 Simia annulare; Beghin et al., p. 73, pl. 3, fig. e. 2018 Simia annulare; Loron and Moczydłowska, p. 21, pl. 5, figs. 1-3. 2019 Simia annulare; Miao et al., p. 192, fig. 7e-g. 2019a Simia annulare; Loron et al., p. 358, fig. ...
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... Bundles of tightly packed parallel filamentous sheaths are present and identified as Polytrichoides lineatus (Hermann, 1974) (Fig. 8.3). Uniseriate trichomes of Oscillatoriopsis (Schopf, 1968) Butterfield in Butterfield et al., 1994 and pseudoseptate filaments of Tortunema (Hermann, 1974) Butterfield in Butterfield et al., 1994 are also present (Fig. 8.4, 8.6) as well as a single specimen of Palaeolyngbya ( Schopf, 1968) Butterfield in Butterfield et al., 1994, with the sheath enclosing remains of the original cells (Fig. 8.5). A small filament with regularly distributed annular bulges is recognized as Cephalonyx Weiss, 1984 (5.5 μm wide, n = 1; Fig. 8.7), and a large unknown form with a ...
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... L. tenuissima) and shape of the folds indicating wall flexibility (sinuous for L. minutissima and L. tenuissima; lanceolate for L. crassa and L. jacutica) following the principles of Javaux and Knoll (2017). However, a large number of specimens in different samples are opaque and do not display conspicuous taphonomic folds or cracks (leiospheres; Fig. 6.4). These size-class species are morphotaxa that are probably polyphyletic and do not necessarily coincide with biological species, but they are a useful tool to describe diversity of forms within an assemblage and to compare with previous micropaleontological ...
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... microfossils.-The long-ranging taxon Valeria lophostriata, with characteristic circular ridges on the wall inner surface, is abundant throughout the assemblage (Fig. 4.1). Rare specimens of Simia annulare ornamented with an equatorial flange and the disphaeromorph (vesicle Figure 8. Filamentous forms. (1) Mat of Siphonophyccus spp., 76553-u49. (2) Syphonophyccus gigas, 76085-l46. (3) Polythrichoides lineatus. (4) Oscillatoriopsis sp., 76085-e53,3. (5) Palaeolyngbya sp., 76092-n44,4. (6) Tortunema sp., ...
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... is from sample HB07-41A 232 m; (2,3,8) are from sample CL17-14; (5-7) are from sample HB07-41A 183 m. Scale bar in (1) = 30 μm for (5-7), 60 μm for (1, 4), 120 μm for (3,8), and 200 μm for (2). another vesicle) Pterospermopsimorpha insolita are also recognized (Fig. 4.2, 4.3). ...
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... CL17-14; (5-7) are from sample HB07-41A 183 m. Scale bar in (1) = 30 μm for (5-7), 60 μm for (1, 4), 120 μm for (3,8), and 200 μm for (2). another vesicle) Pterospermopsimorpha insolita are also recognized (Fig. 4.2, 4.3). In addition, five specimens of Osculosphaera hyalina, with a pylome excystment structure (circular opening) are documented (Fig. 4.6). Vesicles of Dictyosphaera macroreticulata (Fig. 4.7-4.9) and Satka favosa (Fig. 4.10, 4.11) are also present. D. macroreticulata has a wall made of tessellate hexagonal plates, whereas wall plates of S. favosa are larger, fewer, and have a polygonal or quadrate shape (see Knoll, 2017 andLoron et al., 2019a for discussion of this ...
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... bar in (1) = 30 μm for (5-7), 60 μm for (1, 4), 120 μm for (3,8), and 200 μm for (2). another vesicle) Pterospermopsimorpha insolita are also recognized (Fig. 4.2, 4.3). In addition, five specimens of Osculosphaera hyalina, with a pylome excystment structure (circular opening) are documented (Fig. 4.6). Vesicles of Dictyosphaera macroreticulata (Fig. 4.7-4.9) and Satka favosa (Fig. 4.10, 4.11) are also present. D. macroreticulata has a wall made of tessellate hexagonal plates, whereas wall plates of S. favosa are larger, fewer, and have a polygonal or quadrate shape (see Knoll, 2017 andLoron et al., 2019a for discussion of this species). Oval vesicles ornamented with spiral grooves, ...
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... 60 μm for (1, 4), 120 μm for (3,8), and 200 μm for (2). another vesicle) Pterospermopsimorpha insolita are also recognized (Fig. 4.2, 4.3). In addition, five specimens of Osculosphaera hyalina, with a pylome excystment structure (circular opening) are documented (Fig. 4.6). Vesicles of Dictyosphaera macroreticulata (Fig. 4.7-4.9) and Satka favosa (Fig. 4.10, 4.11) are also present. D. macroreticulata has a wall made of tessellate hexagonal plates, whereas wall plates of S. favosa are larger, fewer, and have a polygonal or quadrate shape (see Knoll, 2017 andLoron et al., 2019a for discussion of this species). Oval vesicles ornamented with spiral grooves, S. segmentata (Fig. 4.12- 4.14), are ...
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... and Satka favosa (Fig. 4.10, 4.11) are also present. D. macroreticulata has a wall made of tessellate hexagonal plates, whereas wall plates of S. favosa are larger, fewer, and have a polygonal or quadrate shape (see Knoll, 2017 andLoron et al., 2019a for discussion of this species). Oval vesicles ornamented with spiral grooves, S. segmentata (Fig. 4.12- 4.14), are abundant, and rare fragments of Lineaforma elongata, a large tube with longitudinal striations on its wall surface, also occur. We also report the presence of a new taxa, Dictyosphaera smaugi n. sp. (Fig. 5). These microfossils possess a smooth wall except for a localized area of their wall made of hexagonal platelets (see Fig. ...
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... (processes-bearing) microfossils.-Three specimens of Germinosphaera bispinosa are present, one of them bearing two equatorial processes (Fig. 4.4, 4.5). The Fort Confidence assemblage also includes the second report of Germinosphaera alveolata (Fig. 7.4-7.10). SEM reveals that the microfossils are covered with small overlapping scale-like structures ( Fig. 7.8-7.10) and not alveoli as suggested in its original description ( Miao et al., ...
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... (processes-bearing) microfossils.-Three specimens of Germinosphaera bispinosa are present, one of them bearing two equatorial processes (Fig. 4.4, 4.5). The Fort Confidence assemblage also includes the second report of Germinosphaera alveolata (Fig. 7.4-7.10). SEM reveals that the microfossils are covered with small overlapping scale-like structures ( Fig. 7.8-7.10) and not alveoli as suggested in its original description ( Miao et al., ...
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... Changzhougou Formation, China ( Miao et al., 2019). The Dismal assemblage also contains one of the oldest known specimens of O. hyalina, a pylome-bearing microfossil previously reported only from the Neoproterozoic ( Butterfield et al., 1994). In addition, the pylome excystment structure documented here on Dictyosphaera macroreticulata (Fig. 4.7) confirms the suggestion that this species opened in a more complex way than simple medial splitting ( Yin et al., 2005;Moczydłowska et al., 2011;AgicétAgicét al., ...
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The apparently obligate symbiosis between the diazotroph Candidatus Atelocyanobacterium thalassa (UCYN-A) and its haptophyte host, Braarudosphaera bigelowii, has recently been found to fix dinitrogen (N2) in polar waters at rates (per cell) comparable to those observed in the tropical/subtropical oligotrophic ocean basins. This study presents the n...
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... However, Mesoproterozoic records of such fungus-like fossils (e.g. Loron et al., 2021;Miao et al., 2021) lack the exceptional preservational state of the Volyn biota. While a model was proposed involving hydrothermal fluids to explain rapid preservation for the Volyn biota, this remains a unique process without analogue and therefore requires exceptional supporting evidence. ...
... Ga; Westall et al., 2001) of the rock prior to its study. Some studies have used light microscopy to reveal the internal structure of the organic component (Loron et al., 2019(Loron et al., , 2021Miao et al., 2021). Airborne contamination can occur in the laboratory, and when pristine three-dimensional fossils are identified, these should be checked using light microscopy to ensure there are no fresh cell contents. ...
Franz et al. (2023) report a diverse and three-dimensionally preserved suite of mid-Proterozoic microfossils from miarolitic cavities within the granitic Volyn pegmatite field, a major granitic plutonic complex in NW Ukraine. The biota is dated at between ∼ 1.76 and ∼ 1.5 Ga and includes fungus-like objects. This biota is reported as evidence of organisms living within the continental lithosphere, illuminating part of a ∼ 1.8–0.8-billion-year interval of the Proterozoic Eon characterised by relatively low climatic variability and slow biological evolution. We show that at least some of this putative diversity represents modern contamination including plant hairs, a distinctive pollen grain assignable to the extant conifer genus Pinus, and likely later fungal growth. Comparable diversity is shown to exist in modern museum dust, presented as an example of potential airborne contamination and calling into question whether any part of the Volyn “biota” is biological in origin. We emphasise the need for scrupulous care in collecting, analysing, and identifying Precambrian microfossils.
... Several early eukaryote species possess walls composed of multiple repeated units-tessellated polygons, attached plates, or overlapping scales-interpreted to have been formed in intracellular vesicles and transported to the cell's periphery. Among the oldest of these is Satka favosa (Figure 3f,g), which exhibits a wall composed of numerous polygonal organic plates, <1 µm thick and several micrometers across (e.g., 60,63,81). The plates are convex outward. ...
... In specimens where plates are partly separated, it is apparent that the plates do not fit perfectly together (66, figure 3b) (Figure 3f ), suggesting that they were formed individually and subsequently joined. Some of the same rocks preserve another species, Germinosphaera alveolata (Figure 3h), that possesses numerous <1-µm organic scales that form an irregular and densely imbricated layer (81,90). Today, similar plates and scales occur in a phylogenetically diverse array of eukaryotes, implying that they evolved convergently many times over, as either entirely organic or mineralized (e.g., siliceous, calcareous) structures. ...
The origin of modern eukaryotes is one of the key transitions in life's history, and also one of the least understood. Although the fossil record provides the most direct view of this process, interpreting the fossils of early eukaryotes and eukaryote-grade organisms is not straightforward. We present two end-member models for the evolution of modern (i.e., crown) eukaryotes—one in which modern eukaryotes evolved early, and another in which they evolved late—and interpret key fossils within these frameworks, including where they might fit in eukaryote phylogeny and what they may tell us about the evolution of eukaryotic cell biology and ecology. Each model has different implications for understanding the rise of complex life on Earth, including different roles of Earth surface oxygenation, and makes different predictions that future paleontological studies can test.
... Most of the spheroidal acritarchs (e.g., Leiosphaeridia and Navifusa), aggregated sphaeromorph vesicles (e.g., Synsphaeridium), and unbranched filamentous aggregates (e.g., Polytrichoides and Siphonophycus) have long stratigraphic and wide geographic ranges. For example, the bundled filamentous fossil P. lineatus is widely distributed in Proterozoic rocks, including northern America (Hofmann and Jackson, 1994;Loron et al., 2021), western and central Africa (Baludikay et al., 2016;Beghin et al., 2017), southeastern Siberia (Hermann, 1990), eastern European platform (Vorob'eva et al., 2015), and North China (Tang et al., 2013Li et al., 2019). However, we note that simple leiospheres in the Diaoyutai assemblage are characterized by their large vesicles (500-700 μm in diameter, Fig. 7), generally larger than those reported in other Meso-Neoproterozoic assemblages; for example, leiospheres in the ca. ...
... (Table S1). The Diaoyutai assemblage has thus far yielded only one acanthomorph species, Germinosphaera bispinosa (Fig. 6a-d), which is a widely distributed acanthomorph in Meso-Neoproterozoic sedimentary sequences (e.g., Butterfield et al., 1994;Baludikay et al., 2016;Loron and Moczydłowska, 2017;Miao et al., 2021;Loron et al., 2019aLoron et al., , 2021. In comparison, the lower Shaler Supergroup (ca. ...
... 1 前 言 真核生物是生物圈的重要组成部分, 保存在 细碎屑岩中的有机质壁微体化石记录为探索早期 真核生物的演化提供了基础(如: Butterfield et al., 1994;Javaux et al., 2001;Agić et al., 2017;Loron et al., 2019;Miao et al., 2021)。一般认为, 确切的真 核生物化石出现于古元古代晚期(>1650 Ma)。例 如, 我国华北汝阳群和长城群报道的具有复杂纹 饰 的 化 石 Dictyosphaera 、 Valeria 和 Shuiyousphaeridium (Yin, 1997;Lamb et al., 2009;Peng et al., 2009;Agić et al., 2015Agić et al., , 2017Miao et al., 2019) (Brocks et al., 2005Luo et al., 2015Luo et al., , 2016Gueneli et al., 2018;Nguyen et al., 2019)。因此, 生物化石和生物标志 物分别从不同角度展示了中元古代时期的海洋生 物面貌特征, 即海洋生态系统中真核生物丰度极 低 的情况下伴随许多关键的真核生物创新事件 (Butterfield, 2015;Porter, 2020)。近年来, 有许多中 元古代生物群被报道 (Baludikay et al., 2016;Javaux and Knoll, 2016;Adam et al., 2017;Loron et al., 2019Loron et al., , 2021Miao et al., 2021), 这为进一步完善中元古代生物演化提供了 丰富的材料。但是总体而言, 大量已报道的化石群 集 中 在 中 元 古 代 早 期 和 最 晚 期 , 而 中 期 (Canfield et al., 2018;Zou et al., 2019;Ye et al., 2021;Li et al., 2022) (Barker and Pawlewicz, 1994;Beyssac et al., 2002;Rahl et al., 2005;Aoya et al., 2010;Lahfid et al., 2010;Kouketsu et al., 2014) (Timofeev et al., 1976), 但是明 显小于Bylot超群的标本, 约45-68 µm长, 34-47 µm宽 (Hofmann and Jackson, 1994)。最近在中元古 ...
... (3%)。 聚球状化石也占很大比例, 包 括 Synsphaeridium sp. (15.5%) 和 Eomicrocystis malgica (5.6%)。具有复杂纹饰或特殊结构的标本 非常稀少。 台子组微体化石的另一个特点是标本都比较 小, 平均直径远小于相近时期生物群(Tang et al.,Beghin et al., 2017;Loron et al., 2019Loron et al., , 2021Miao et al., 2021)。本文对简单球形化石标本统计 结果显示大部分直径在20-50 μm之间, 均值33.4 ± 12.7 μm (N = 193)。而一些聚合体的单个膜壳更微 小, 比如E. malgica直径峰值为6.2 ± 1.3 μm (N = 15), Synsphaeridium sp.直径峰值为12.spp.、Synsphaeridium ...
The Shennongjia Group on the northern margin of the Yangtze Platform consists of thick marine carbonate and clastic rocks of the middle and late Mesoproterozoic Era. The middle part of the Shennongjia Group, i.e., the Taizi Formation, consists of sandstone and silty shale in the lower part and fine-crystalline limestone in the upper part. According to previous investigations, organic-walled microfossils of the Taizi Formation are the most abundant among the formations of the Shennongjia Group. To further improve the understanding of the biodiversity during the deposition of the Taizi Formation, we carry out a micropaleontological investigation on the fine-clastic rocks of the Taizi Formation from the Tiechanghe section, Shennongjia National Park, Hubei Province. Our investigation reveals a moderately diverse assemblage of organic-walled microfossils dominated by spherical vesicles and aggregates with a few complex vesicle forms. In addition, the fossil specimens of the Taizi assemblage are very small, generally ranging from 20 to 50 μm. A total of 11 microfossil taxa belonging to seven genera have been identified. These taxa include simple spherical form (Leiosphaeridia crassa, Leiosphaeridia minutissima, Leiosphaeridia jacutica, Leiosphaeridia bicrura, and Leiosphaeridia sp.), cell aggregate form (Synsphaeridium sp. and Eomicrocystis malgica), and complex vesicle form (Navifusa sp., Satka sp., Germinosphaera sp., and Arctacellularia tetragonala). As for biological affinity, prokaryotes are the predominant components, whereas eukaryotes are scarce. The low diversity and small individual size of the microfossils of the Taizi assemblage, which might be caused by a harsh living environment or insufficient essential nutrients, are significantly different from those of the earlier and later biological communities. Furthermore, the Taizi Formation has experienced low- to middle-grade metamorphism with peak metamorphic temperatures of ~280°C based on Raman geothermometers of individual organic-walled microfossils, which is higher than those of other well-preserved Proterozoic microfossils. The high burial temperature may affect the preservation quality of the microfossils of the Taizi assemblage.扬子台地北缘神农架群发育一套中元古代中期和晚期的海相碳酸盐岩与碎屑岩地层, 其中台子组是神农架群中部地层, 也是该群古生物化石丰度最高的组。本文利用化学浸泡法对中元古代中期台子组细粒碎屑岩进行微体化石研究, 结果显示: 台子组化石总的特征是组合简单、化石个体较小, 大部分标本直径介于20–50 μm。本文共鉴定出微体化石7属11种, 包括光面球形类Leiosphaeridia crassa、L. minutissima、L. jacutica、L. bicrura和Leiosphaeridia sp., 细胞聚合体Synsphaeridium sp.、Eomicrocystis malgica和相对复杂的疑源类Navifusa sp.、Satka sp.、Germinosphaera sp.与Arctacellularia tetragonala。台子组微体化石组合中原核生物是主要的化石类型,真核生物丰度很低。其化石多样性和膜壳平均直径远小于邻近时期的生物化石群落, 这可能与台子组沉积期的地表环境特征以及独特的生物群落特征有关。拉曼光谱分析表明台子组有机质处于较高的热演化阶段, 埋藏温度约280℃, 过高的埋藏温度也可能降低了台子组化石保存质量。
... In overall morphology, some of the CUB Type 3 cells resemble those of Germinosphaera alveolata (Miao et al., 2019) from the late Paleoproterozoic Chuanlinggou Formation of China, which were reported recently also from the Mesoproterozoic Fort Confidence Formation, Dismal Lakes Group (1590-1270 Ma) in Arctic Canada (Loron et al., 2021), as having a spheroidal cell body, with a large robust process that is hollow, broad-based, and slightly tapering toward the end. A more striking similarity is the imbricated, scale-like ornaments on the cell surface, present in both the Arctic Canada and Gunflint Chert specimens (compare Loron et al., 2021, fig. ...
... with Fig. 4D-4F of this study). The only notable difference is the cell size; the cells from the Mesoproterozoic of Arctic Canada were described by Loron et al. (2021) to have a range of 25.9-57.0 mm, although a small ovoidal specimen they illustrated has a short diameter of *20 mm and a long diameter of *24 mm (excluding the process). ...
... Individual cells of CUBs examined in this study have diameters ranging from 13 to 25 mm. This size range is smaller than that of most of the younger acritarch or other eukaryote-like microfossils of Paleo-to Mesoproterozoic age (commonly >50 mm in diameter; e.g., Agić et al., 2017;Miao et al., 2019;Loron et al., 2021), but this smaller size range is well within that of modern unicellular green algae (Kaźmierczak, 1976). ...
Fossil evidence of eukaryotic life older than 1.8 Ga has long been debated because known fossils of that age usually lack cellular micro- and ultra-structures that bear strong affinities to eukaryotes. These include fossils of the ∼1.9 Ga Gunflint Chert microbiota that, despite being exceptionally well preserved, have suffered from cellular degradation, which poses challenges to studying their delicate cellular structures. In this study, we use an extended-focal-depth imaging technique, in combination with scanning electron microscopy, to document multiple types of large (10-35 μm diameter), cyst-like bodies based on distinctive details such as (1) radially arranged internal strands similar to those in some acritarchs and dinoflagellates; (2) regularly spaced long tubular processes, stubby pustules, and/or robust podia on the cell surface; (3) reticulate cell-wall sculpturing such as scale-like tubercles, pits, and ridges; and (4) internal bodies that may represent membrane-bound organelles. These micro- and ultra-structures provide strong morphological evidence for the presence of protists in the late Paleoproterozoic.
... Over the last fifty years, many fossils have been described as eukaryotic fossils from the Proterozoic rocks, both at the level of conventional palaeontology and molecular studies (Chernikova et al., 2011;Knoll, 2014;Bonneville et al., 2020;Carlisle et al., 2021). These fossils, distinctly documented worldwide in marine sedimentary successions, play a significant role in understanding the patterns of the earth's atmospheric and biological evolution in deep time (Loron et al., 2021;Miao et al., 2021). ...
... Not all, but only morphologically complex acritarchs, having distinct vesicle ornamentations and sculpture, are generally assigned as eukaryotic fossils and also provide important information about taxonomic diversity and morphological disparity (Huntley et al., 2006). Distinct sphaeromophic acritarchs viz., Dictyosphaera macroreticulata and Valeria lophostriata are among the oldest known morphologically and taxonomically recognized eukaryotic fossils which are widely distributed in the latest Palaeoproterozoic to early Neoproterozoic (Tonian) organicwalled microfossils assemblages of Australia, Africa, Canada, China, and Siberia (Knoll et al., 2006;Nagovitsin, 2009;Javaux, 2011;Singh and Sharma, 2014;Agić et al., 2015;Cohen and Macdonald, 2015;Vorob'eva et al., 2015;Sergeev et al., 2016;Adam et al., 2017;Agić et al., 2017;Miao et al., 2019;Singh et al., 2019b;Loron et al., 2021). In the past few years, continuous attempts have been made to understand the life cycle and affinity of these acritarchs based on morphology and vesicle (Moczydłowska and Willman, 2009;Moczydłowska et al., 2010;Agić et al., 2015;. ...
... Compression and compaction folds, dense concentric striations, and polygonal plates on the vesicle wall as well as deformation in specimens are common characteristics in microfossils. Such complex morphologies are diagnostically recognized as extant grade eukaryotes (Knoll et al., 2006;Nagovitsin, 2009;Javaux, 2011;Singh and Sharma, 2014;Agić et al., 2015;Cohen and Macdonald, 2015;Vorob'eva et al., 2015;Sergeev et al., 2016;Adam et al., 2017;Agić et al., 2017;Miao et al., 2019;Singh et al., 2019b;Loron et al., 2021). Systematics and geographical distributions of the identified OWMs are provided below. ...
... Over the last fifty years, many fossils have been described as eukaryotic fossils from the Proterozoic rocks, both at the level of conventional palaeontology and molecular studies (Chernikova et al., 2011;Knoll, 2014;Bonneville et al., 2020;Carlisle et al., 2021). These fossils, distinctly documented worldwide in marine sedimentary successions, play a significant role in understanding the patterns of the earth's atmospheric and biological evolution in deep time (Loron et al., 2021;Miao et al., 2021). ...
... Not all, but only morphologically complex acritarchs, having distinct vesicle ornamentations and sculpture, are generally assigned as eukaryotic fossils and also provide important information about taxonomic diversity and morphological disparity (Huntley et al., 2006). Distinct sphaeromophic acritarchs viz., Dictyosphaera macroreticulata and Valeria lophostriata are among the oldest known morphologically and taxonomically recognized eukaryotic fossils which are widely distributed in the latest Palaeoproterozoic to early Neoproterozoic (Tonian) organicwalled microfossils assemblages of Australia, Africa, Canada, China, and Siberia (Knoll et al., 2006;Nagovitsin, 2009;Javaux, 2011;Singh and Sharma, 2014;Agić et al., 2015;Cohen and Macdonald, 2015;Vorob'eva et al., 2015;Sergeev et al., 2016;Adam et al., 2017;Agić et al., 2017;Miao et al., 2019;Singh et al., 2019b;Loron et al., 2021). In the past few years, continuous attempts have been made to understand the life cycle and affinity of these acritarchs based on morphology and vesicle (Moczydłowska and Willman, 2009;Moczydłowska et al., 2010;Agić et al., 2015;. ...
... Compression and compaction folds, dense concentric striations, and polygonal plates on the vesicle wall as well as deformation in specimens are common characteristics in microfossils. Such complex morphologies are diagnostically recognized as extant grade eukaryotes (Knoll et al., 2006;Nagovitsin, 2009;Javaux, 2011;Singh and Sharma, 2014;Agić et al., 2015;Cohen and Macdonald, 2015;Vorob'eva et al., 2015;Sergeev et al., 2016;Adam et al., 2017;Agić et al., 2017;Miao et al., 2019;Singh et al., 2019b;Loron et al., 2021). Systematics and geographical distributions of the identified OWMs are provided below. ...
The present study enriches the records of the Proterozoic eukaryotic fossils with well-preserved specimens of the genus Dictyosphaera macroreticulata and Valeria lophostriata reported from the late Mesoproterozoic Chaporadih Formation of the Chandarpur Group, Chhattisgarh Supergroup. Results of integrated studies, involving Confocal Laser Scanning Microscopy (CLSM) over the Transmitted Light Microscopy (TLM), are presented to understand the submicron level morphology of Organic Walled Microfossils (OWM). In the global context, Tappania, Dictyosphaera, and Valeria constitute a biozone of which the latter two are important constituents. These elements are part of the widely distributed and long-ranging forms that are found in the latest Palaeoproterozoic to early Neoproterozoic (Tonian) organic-walled microfossils assemblages. Collectively, their occurrence in the Chhattisgarh Supergroup demonstrates a new record of eukaryotic fossils from the Proterozoic succession of India.
... Over the last fifty years, many fossils have been described as eukaryotic fossils from the Proterozoic rocks, both at the level of conventional palaeontology and molecular studies (Chernikova et al., 2011;Knoll, 2014;Bonneville et al., 2020;Carlisle et al., 2021). These fossils, distinctly documented worldwide in marine sedimentary successions, play a significant role in understanding the patterns of the earth's atmospheric and biological evolution in deep time (Loron et al., 2021;Miao et al., 2021). ...
... Not all, but only morphologically complex acritarchs, having distinct vesicle ornamentations and sculpture, are generally assigned as eukaryotic fossils and also provide important information about taxonomic diversity and morphological disparity (Huntley et al., 2006). Distinct sphaeromophic acritarchs viz., Dictyosphaera macroreticulata and Valeria lophostriata are among the oldest known morphologically and taxonomically recognized eukaryotic fossils which are widely distributed in the latest Palaeoproterozoic to early Neoproterozoic (Tonian) organicwalled microfossils assemblages of Australia, Africa, Canada, China, and Siberia (Knoll et al., 2006;Nagovitsin, 2009;Javaux, 2011;Singh and Sharma, 2014;Agić et al., 2015;Cohen and Macdonald, 2015;Vorob'eva et al., 2015;Sergeev et al., 2016;Adam et al., 2017;Agić et al., 2017;Miao et al., 2019;Singh et al., 2019b;Loron et al., 2021). In the past few years, continuous attempts have been made to understand the life cycle and affinity of these acritarchs based on morphology and vesicle (Moczydłowska and Willman, 2009;Moczydłowska et al., 2010;Agić et al., 2015;. ...
... Compression and compaction folds, dense concentric striations, and polygonal plates on the vesicle wall as well as deformation in specimens are common characteristics in microfossils. Such complex morphologies are diagnostically recognized as extant grade eukaryotes (Knoll et al., 2006;Nagovitsin, 2009;Javaux, 2011;Singh and Sharma, 2014;Agić et al., 2015;Cohen and Macdonald, 2015;Vorob'eva et al., 2015;Sergeev et al., 2016;Adam et al., 2017;Agić et al., 2017;Miao et al., 2019;Singh et al., 2019b;Loron et al., 2021). Systematics and geographical distributions of the identified OWMs are provided below. ...
The present study enriches the records of the Proterozoic eukaryotic fossils with well-preserved specimens of the genus Dictyosphaera macroreticulata and Valeria lophostriata reported from the late Mesoproterozoic Chaporadih Formation of the Chandarpur Group, Chhattisgarh Supergroup. Results of integrated studies, involving Confocal Laser Scanning Microscopy (CLSM) over the Transmitted Light Microscopy (TLM), are presented to understand the submicron level morphology of Organic Walled Microfossils (OWM). In the global context, Tappania, Dictyosphaera, and Valeria constitute a biozone of which the latter two are important constituents. These elements are part of the widely distributed and long-ranging forms that are found in the latest Palaeoproterozoic to early Neoproterozoic (Tonian) organic-walled microfossils assemblages. Collectively, their occurrence in the Chhattisgarh Supergroup demonstrates a new record of eukaryotic fossils from the Proterozoic succession of India.
A new assemblage of Early Vendian (Middle Ediacaran) microfossils, including acanthomorphic acritarchs and various filamentous remains, as well as sphaeromorphic striated vesicles of Valeria, which are not characteristic of deposits of this age, is described in the Ura Formation of the Dal’nyaya Taiga Group of the Patom Basin. A new species of acanthomorphs Hocosphaeridium crispum sp. nov. is described. The selective confinement of the Ediacaran eukaryotic phytoplankton taphocoenoses to the open-sea proximal facies of the inner ramp is shown.
This work presents a detailed taxonomic study on organic-walled microfossils from the Ediacaran Sete Lagoas Formation (Bambuí Group) at the Barreiro section in the Januária area of the São Francisco basin, Brazil. Seven species are described, including Siphonophycus robustum (Schopf, 1968), Ghoshia januarensis new species, Leiosphaeridia crassa (Naumova, 1949), Leiosphaeridia jacutica (Timofeev, 1966), Leiosphaeridia minutissima (Naumova, 1949), Leiosphaeridia tenuissima Eisenack, 1958, and Germinosphaera bispinosa Mikhailova, 1986. These taxa are recovered for the first time in the Sete Lagoas Formation. They occur abundantly in the lower portion of the studied section, but only Ghoshia januarensis is present in the upper part of the studied section, probably due to environmental or taphonomic changes. Leiosphaeridia species, particularly Leiosphaeridia minutissima, dominate the organic-walled microfossil assemblage. Although most taxa described here have long stratigraphic ranges, they are consistent with a terminal Ediacaran age as inferred from detrital zircon data and tubular fossils (e.g., Cloudina and Corumbella) from the Sete Lagoas Formation.
UUID: http://zoobank.org/7f92b900-0176-4da6-93a3-fd51edb22cbf
