Article

Cloudina lucianoi ( Beurlen and Sommer, 1957 ), Tamengo Formation, Ediacaran, Brazil: Taxonomy, Analysis of Stratigraphic Distribution and Biostratigraphy

Article

Cloudina lucianoi ( Beurlen and Sommer, 1957 ), Tamengo Formation, Ediacaran, Brazil: Taxonomy, Analysis of Stratigraphic Distribution and Biostratigraphy

If you want to read the PDF, try requesting it from the authors.

Abstract

The genus Cloudina Germs, 1972 includes seven species restricted to Ediacaran strata: 1. Cloudina lucianoi (Beurlen and Sommer, 1957) (Tamengo Formation, Brazil); 2. Cloudina hartmanae Germs, 1972 (Nama Group, Namibia); 3. Cloudina riemkeae Germs, 1972 (Nama Group, Namibia; 4. Cloudina waldei Hahn and Pflug, 1985 (Tamengo Formation, Brazil); 5. Cloudina lijiagouensis Zhang et al., 1992 (Yangtze Platform, China), 6. Cloudina sinensis Zhang et al., 1992, (Yangtze Platform, China); and 7. Cloudina carinata Cortijo et al., 2010 (Spain). Cloudina lucianoi was originally attributed to Aulophycus Fenton and Fenton, 1939 and was later suggested to represent a species of Cloudina. Briefly, Cloudina differs from Aulophycus in having a lamellar sessile benthic funnel-within-funnel skeleton instead of a tube-shaped skeleton. Additionally, Aulophycus has been considered restricted to the Cambrian, whereas all Cloudina species have been recorded only in the Ediacaran, with extinction of all species at the end of this period being observed. The results of taxonomic studies of Cloudina lucianoi are presented, as well as a revision of type-section, morphometric analysis, stratigraphic distribution and biostratigraphy. For this focal species, a new description, new diagnosis and morphometric analyses are included. Regarding taxonomy, a brief history is given of the Genus Cloudina, with remarks comparing Cloudina lucianoi with four other species. Additionally, new illustrations of type-material of Cloudina lucianoi, Cloudina hartmanae and Cloudina riemkeae are presented. The aforementioned species are revised in this report; additionally, an up-to-date stratigraphic approach and illustrations of the type-horizon of this species are included. A detailed comparison of the seven species is conducted to present a clearer diagnosis for this species described with material recovered from Brazil.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... In Brazil, the most important Ediacaran geological record is the Tamengo Formation, of the Corumbá Group (Boggiani et al., 2010;Walde et al., 2015;Amorim et al., 2020). The importance of this unit comes mainly from the occurrence of upper Ediacaran guide fossils, such as Cloudina lucianoi and Corumbella werneri (e.g., Hahn et al., 1982;Adôrno et al., 2017). However, this unit still lacks a detailed characterization of its depositional system, when compared with the main references for the Ediacaran period. ...
... Dolostones and phosphorites occur locally. The paleontological content of the Tamengo Formation includes skeletal macrofossils, especially C. lucianoi (Beurlen and Sommer, 1957) an index species for the late Ediacaran (e.g., Grant, 1990;Adôrno et al., 2017), and C. werneri . Recently, a rich assemblage of ichnofossils, vendotaenids, and organic-walled microfossils was also described (e.g., Adôrno, 2019). ...
... Recently, a rich assemblage of ichnofossils, vendotaenids, and organic-walled microfossils was also described (e.g., Adôrno, 2019). These fossil assemblages have drawn most part of the attention in the studies on the Tamengo Formation (Fairchild, 1978;Walde et al., 1982;Zaine and Fairchild, 1985;Zaine, 1991;Hidalgo, 2002;Gaucher et al., 2003;Kerber et al., 2013;Tobias, 2014;Walde et al., 2015;Adôrno et al., 2017;Becker-Kerber et al., 2017;Parry et al., 2017;Walde et al., 2019;Diniz et al., 2021) C. lucianoi is usually found in limestones, whereas C. werneri occurs in shales (Adôrno et al., 2017;Oliveira et al., 2019;Adôrno, 2019;Amorim et al., 2020). Boggiani (1998) suggests that the Tamengo Formation formed above the Bocaina Formation during a transgression, establishing a slope-break ramp system marked by reworking of the shallower sediment. ...
Article
Full-text available
The Ediacaran is a period characterized by the diversification of early animals and extensive neritic carbonate deposits. These deposits are still not well understood in terms of facies and carbon isotope composition (δ13C). In this study we focus on the Tamengo Formation, in southwestern Brazil, which constitutes one of the most continuous and well-preserved sedimentary record of the late Ediacaran in South America. We present new detailed lithofacies and stable isotopes data from two representative sections (Corcal and Laginha) and revise the paleoenvironmental and stratigraphic interpretation of the Tamengo Formation. The Corcal section consists of neritic deposits including shallow-water limestone beds, alternated with shale and subordinate marl beds. These facies yield specimens of the Ediacaran fossils Cloudina lucianoi and Corumbella werneri. On the other hand, the Laginha section shows more heterogeneous facies, such as impure carbonates, breccias, marls, and subordinate mudstone beds, as well as no evidence of Corumbella werneri. The stable carbon isotope record is also different between the two sections, despite belonging to the same unit. The Corcal section displays higher and more homogeneous δ13C values, consistent with those of Ediacaran successions worldwide. The Laginha section, instead, displays more variable δ13C values, which suggest the influence of local and post depositional processes. The difference between the two sections was attributed to the different distance from the shore. We propose that the difference is due to topographic variations of the continental platform, which, at the Laginha site, was steeper and controlled by extensional faults. Therefore, the Corcal section is a better reference for the Tamengo Formation, whereas the Laginha is more particular and influenced by local factors. Besides, the lithofacies associations of the Tamengo Formation are like those of the Doushantuo and Dengying formatios, in South China, with no significant biogenic carbonate buildups, and different from those of other important Ediacaran units, such as the Nama Group in Nmibia and the Buah Formation in Oman. Our work highlights the complexity and heterogeneity of Ediacaran carbonate platforms and of their carbon isotopic composition. In addition, we characterize the Corcal section as a possible reference for the Ediacaran in South America.
... Although these organisms are considered useful markers for identifying the latest Ediacaran (Xiao et al., 2016) with proposed biozonations (Gaucher and Germs, 2009;Adorno et al., 2017;Zhu et al., 2017), there is no consensus on their utility for global correlation. One of the main obstacles is their taxonomic confusion. ...
... 3, 4), Kliphoek? (Grant, 1990), Huns (Grant, 1990;Germs, 1995), and Spitskop (Germs, 1995) members of the Nama Group, South Namibia; Tamengo Formation, Corumbá Group, Mato Grosso do Sul State, Brazil (Beurlen and Sommer, 1957;Adorno et al., 2017;; Sete Lagoas Formation, Bambuí Group, Januária area, central Brazil (Warren et al., 2014); Tagatiya Guazu Formation, Itapucumi Group, northeastern Paraguay (Warren et al., 2011(Warren et al., , 2017 this study); Shibantan (Chen and Wang, 1977;Fig. 7) and Baimatuo (Liang et al., 2020) (Steiner et al., 2007;Yang et al., 2020a); Dengying Formation (Conway Morris et al., 1990;Hua et al., 2005;Cai et al., 2017), Ningqiang County of Shaanxi Province, South China; Kuanchuanpu Formation, Ningqiang County of Shaanxi Province, South China (Yang et al., 2020b); Deep Spring Formation ; reported as Coleolella sp.; Signor et al., 1987; reported as Nevadatubulus; this study), western USA; Villarta Limestone of Ibor Group, Villarta de los Montes Village, Bada-joz Province, Spain (Cortijo et al., 2015b); Byng Formation of Miette Group, Salient Mountain area, British Columbia, Canada (Hofmann and Mountjoy, 2001); Ara Formation of Huqf Group, Birba Area, Oman (Conway Morris et al., 1990); Ust'-Yudoma Formation, Uchur-Maya region, Southeast Siberia (Zhuravlev et al., 2012;Zhu et al., 2017); Tarzhul' Formation in Kuznetsk Alatau (Terleev et al., 2011) and Raiga Formation in Tomsk Region (Kontorovich et al., 2008), West Siberia, Russia. ...
... It is noted that the correction of C. hartmannae to C. hartmanae (e.g., Glaessner, 1976;Adorno et al., 2017) is considered Germs (1972) initially present a corrected spelling of the source name (Professor Olga Hartman) with a consistent presentation of the taxonomic name C. hartmannae through the text. Thus we consider this species name is after an inappropriate latinization and should be considered valid according to the ICZN (1999, Article 32.5.1). ...
Article
The Ediacaran tubular fossils Cloudina, Sinotubulites, and Conotubus are taxonomically revised with type materials. It is proposed that Aulophycus lucianoi Beurlen and Sommer, 1957, is not a senior synonym of Cloudina hartmannae Germs, 1972. Instead, most of its syntypes may be assigned to Sinotubulites or other taxa. Lectotypes of Sinotubulites baimatuoensis Chen et al., 1981, and Conotubus hemiannulatus Zhang and Lin in Lin et al., 1986, are designated from rediscovered syntypes. Sinotubulites baimatuoensis Chen et al., 1981, is reported from the Mooifontein Member of Nama Group at Aar Farm, Namibia. Cloudina waldei Hahn and Pflug, 1985, is assigned to Sinotubulites baimatuoensis, and thus its occurrence range is extended to Brazil. The lectotype of Conotubus hemiannulatus shows corrugations and annulations on the surface distinguishing it from Cloudina and other collared Ediacaran tubular fossils. Based on the taxonomic revision, we propose a Cloudina hartmannae Interval Zone for the terminal Ediacaran with the upper boundary defined by the first appearance datum of Protohertzina anabarica (i.e., the index fossil of the early Cambrian Anabarites trisulcatus-Protohertzina anabarica Assemblage Zone).
... Extensive bibliography has been produced regarding the Corumbá Group and its Ediacaran paleontological record (Beurlen and Sommer, 1957;Fairchild, 1978;Hahn et al., 1982;Walde et al. 1982Walde et al. , 2015Zaine and Fairchild, 1985;Zaine, 1991;Hidalgo, 2002;Gaucher et al., 2003;Kerber et al., 2013;Tobias, 2014;Adorno et al., 2017;Parry et al., 2017) and focusing on stratigraphy and structural features (Barbosa, 1949;Almeida, 1964Almeida, , 1965Almeida, , 1984Alvarenga and Trompette, 1992;Boggiani and Alvarenga, 2004;Gaucher et al., 2003;Babinski et al., 2008;Boggiani et al., 2010;Meira, 2011;Spangenberg et al., 2014;D'el-Rey et al., 2016;Sial et al., 2016) and on sedimentation context (Boggiani et al., 1993;Boggiani, 1998;Oliveira, 2010;Campanha et al., 2011;Fontanela, 2012). ...
... Their contact is controversial at different localities in Corumbá region and surroundings. At Laginha quarry, the contact is abrupt, according to Adorno et al. (2017). At Corcal quarry, Boggiani et al. (2010) consider this contact as well exposed. ...
... The mineral compositions were determined by X-Ray Diffraction (XRD), textures and structures of the mudrocks were studied through Walde et al. (2015)). C. Regional geological map pointing Laginha and Corcal quarries and Corumbá and Ladário cities (modified from Walde et al. (2015) and Adorno et al. (2017)). ...
... Section 1158: O, transverse and longitudinal sections; P-S, transverse sections (note the funnel-in-funnel structure). Scale bars: A, B, E, L, M, N, P-S = 500 µm; D, H, K = 1000 µm; C, F, G, I, O = 2000 µm (Extracted from Adôrno et al., 2017). 60 Figure 4. 8. Two specimens of Cloudina carinata Cortijo et al., 2010, Tamengo Formation, Porto Figueiras section, Corumbá Municipality, Mato Grosso do Sul State, Brazil. ...
... Dentre todos os gêneros que abrigam espécies de animais biomineralizadores do Ediacariano mais superior, Cloudina é o possui maior distribuição geográfica, com ocorrências em diversas seções do Andar Ediacariano mais superior na Namíbia (Grant, 1990), Omã (Conway Morris et al., 1990), Sul da China ( Hua et al., 2005;Cai et al., 2013;Cortijo et al., 2015a), Espanha ( Cortijo et al., 2010;Cortijo et al., 2015b), Sibéria ( Kontorovich et al., 2008Kontorovich et al., , 2009Zhuravlev et al., 2012;Grazhdankin et al., 2015), Canadá (Hofmann & Mountjoy, 2001), México ), Brasil, Argentina e Uruguai ( 2005b;Warren et al., 2014;Adôrno et al., 2017), Paraguai (Warren et al., 2011;2017;) e California (Grant, 1990Zhuravlev et al., 2012). Especies do animal biomineralizador Sinotubulites Chen et al., 1981 também tem distribuição geográfica ampla e têm sido descritos em seções do Ediacariano mais superior do Sul da China (Cai et al., 2015), México (McMenamin, 1985), na California e Nevada nos Estados Unidos ( Signor et al., 1987), e na Espanha ( Cortijo et al., 2015b). ...
... O Grupo Corumbá é constituído da base para o topo pelas formações Cadieus, Cerradinho, Bocaina, Tamengo e Guaiucurus. Trabalhos têm sido produzidos sobre a paleontologia do Grupo Corumbá (Beurlen & Sommer, 1957;Fairchild, 1978;Hahn et al., 1982;Walde et al., 1982;Zaine 1991;Hidalgo, 2002;Becker-Kerber et al., 2013;Tobias, 2014;Pacheco, 2012;Pacheco et al., 2011;Walde et al., 2015;Adôrno et al., 2017;Parry et al., 2017) e também sobre a estratigrafia e evolução tectono-estrutural (Barbosa, 1949;Almeida, 1964Almeida, , 1965Almeida, , 1984Boggiani & Alvarenga 2004;Babinski et al. 2008;Meira, 2011;Spangenberg et al., 2014;D'el- Rey et al. 2016;Sial et al., 2016) e sobre o contexto sedimentológico ( Boggiani et al., 1993;Oliveira, 2010;Fontanela, 2012;Fazio et al., 2019). ...
Thesis
Full-text available
This work presents results of the taxonomic study and the stratigraphic distribution of twenty-six species of Tamengo and Guaicurus formations in five sections in the Corumbá and Ladário regions: Corcal and Laginha quarries, Porto Sobramil, Porto Figueiras and Ecoparque Cacimba. In addition, paleoecological and paleoenvironmental inferences are presented based on the occurrence of this fossil assemblage and the updating of the lithostratigraphic description of the sections of upper Corumbá Group. Cloudina carinata Cortijo et al., 2010, had documented occurrences in Spain and Siberia, and now it is presented unprecedented occurrence in America continent, from siltstones of the Tamengo Formation at Porto Figueiras section, Brazil. The studied paelobiota is composed of three biomineralizing metazoan: Cloudina lucianoi (Beurlen & Sommer, 1957), Cloudina carinata, Corumbella werneri Hahn et al., 1982, poriferous spicules, putative sponge gemmule and sessile epibionts prokaryotic-colony Vendotaenia antiqua Gnilovskaya, 1971. The present work also deals with taxonomy and stratigraphic distribution of the four ichnospecies: Gordia marina Emmons, 1844, Pilichnus cf. P. dichotomus Uchman, 1999, Didymaulichnus lyelli (Rouault, 1850) and Multina minima Uchman, 2001 that integrate the updated benthic vagile ichnofauna for upper portion of Corumbá Group. Three vendotaenid species were identified: Vendotaenia antiqua in Tamengo Formation, and two species in Guaicurus Formation: Eoholynia corumbensis Gaucher et al., 2003 and Tawuia dalensis Hofmann, 1979 in (Hofmann & Aitken, 1979). The species diversity of the Tamengo Formation fossil assemblage was complemented by the occurrence of sixteen microfissil species that possibly represented marine planktic, characterized by the permineralized microfossil Chuaria circularis Walcott, 1899 and other fifteen species of small sphaeromorphs organic-walled microfossils: Arctacellularia januarensis Denezine, 2018 nomem nudum, Leiosphaeridia ternata (Timofeev, 1966), Leiosphaeridia crassa (Naumova, 1949), Leiosphaeridia jacutica (Timofeev, 1966), Leiosphaeridia minutissima (Naumova, 1949), Leiosphaeridia tenuissima Eisenack, 1958, Leiosphaeridia obsuleta (Naumova, 1949), Bavlinella faveolata Vidal, 1976, Bambuites erichsenii Sommer, 1971, Synsphaeridium sp., Jacutianema sp., Lophosphaeridium sp., Ostiama microcystis Hermann, 1976 in (Timofeev et al., 1976), Navifusa sp. and Gen. 1 sp. 1. A dramatic changed was identified in paleoenvironmental conditions for deposition of Tamengo and Guaicurus formations. It can be clearly seen that there is a possibility of these changes contributing to the elimination of almost 95% of the paleobiota, including the extinction of the epibenthic metazoan and the disappearance of planktic organic-walled microfossil. Among all twenty-two species restricted to Tamengo Formation, there was only one survivior, the ichnospecies Multina minima that occurs in both of these formations. This local disappearance could be attributed to the global Ediacaran-Cambrian mass extinction. In addition, samples were prepared and analyzed from sections of three countries where organic-walled microfossils were recovered: nine species from the Nomtsas Formation, Namibia; four species from the Tagatiya Guazu Formation, Paraguay; and six species from the Dengying Formation, China. These results increased the scarce record of organic-walled microfossils species from these additional uppermost Ediacaran selected sections. Based on the taxonomic results and the stratigraphic distribution of the species identified from the Tamengo Formation in the Corcal quarry, a biostratigraphic essay consisting of seven biozones was proposed. Based on the complementation of the micropaleontological data for the three additional studied sections, and based on the paleontological record present in the bibliography for other selected sections, the Tamengo Formation biozones could be extended covering fifteen uppermost Ediacaran sections from nine countries: Brazil (four sections), Paraguay (three sections), Uruguay, Argentina, Namibia, China, Russia, Canada, United States and Oman, one section each. The seven biozones proposed were named, from bottom to top: Cloudina Assemblage Superzone that is distributed in all 15 analyzed sections. Inserted in this superzone, there are three biozones: Cloudina lucianoi/Corumbella werneri Interval Zone; Corumbella werneri Range Zone; Corumbellla werneri/Cloudina lucianoi Interval Zone, these three biozones have geographic distribution until the present which is restricted to Brazil and Paraguay. Two subzones are proposed: Bavlinella faveolata-Leiosphaeridia minutissima Assemblage Subzone inserted in the base of Corumbella werneri Range Zone and Vendotaenia antiqua-Cloudina lucianoi Concurrent-Range Subzone at the upper portion of the Corumbella werneri/Cloudina lucianoi Interval Zone. The first subzone spans across Brazil, Argentina, Uruguay, Namibia and China, the second across Brazil, Namibia, China and Siberia. Finally, Eoholynia corumbensis Range Zone was proposed in the base of Guaicurus Formation at Laginha quarry, lowermost Cambrian, which is restricted to Laginha quarry locality so far.
... Cloudina was first described in the Nama Group by Germs (1972), and is well represented in Brazil by fossil accumulations in the Tamengo Formation (e.g., Zaine and Fairchild, 1985;Zaine and Fairchild, 1991;Gaucher et al., 2003;Pacheco et al., 2011;Fairchild et al., 2012;Adorno et al., 2017;Becker-Kerber et al., 2017) (Fig. 1), Sete Lagoas Formation (Warren et al., 2014;Paula-Santos et al., 2017), and in diverse places around the planet (Fig. 2), such as Oman (Conway Morris et al., 1990), China (Conway Moris et al. op. cit.), Canada (Hofmann and Mountjoy, 2001), central regions of Spain (Vidal et al., 1994), Uruguay (Gaucher et al., 2003), Paraguay (Warren et al., 2011(Warren et al., , 2017(Warren et al., , 2019 and possibly Antarctica (Yochelson and Stump, 1977). ...
... There exists a prolific debate regarding taxonomic affinities of the Cloudina genus in the four decades of its study (Germs, 1972;Zaine and Fairchild, 1987;Grant, 1990; Conway Morris et al., 1990; Conway- Gaucher et al., 2003); B: Main lithostratigraphic units that occur in around the City of Corumbá (Modified after Lacerda Filho et al., 2004), indicating the sections of Itaú-Saladeiro (1), Laginha (2) and Corcal (3); and C: Simplified geologic map of Tocantis Province, highlighting the Paraguay Southern Belt (Modified after Pimentel et al., 2000;Hasui, 2012). Morris, 1993;Hua et al., 2003Hua et al., , 2005Adorno et al., 2017), including morphology (Grant, 1990;Seilacher, 1999;Adorno et al., 2017;Mehra and Maloof, 2018), mineralogy (Grant, 1990;Brain, 2001;Hua et al., 2005;Becker-Kerber et al., 2017), paleoecology (Germs, 1972;Grant, 1990;Seilacher, 1999;Hua et al., 2005;Cortijo et al., 2010;Becker-Kerber et al., 2017;Mehra and Maloof, 2018) taphonomy (Cortijo et al., 2010;Meira, 2011;Warren et al., 2012;Becker-Kerber et al., 2017Mehra and Maloof, 2018) and extinction (Brain, 2001;Hua et al., 2003;Becker-Kerber et al., 2017). In contrast, information about the sedimentary environment in which these fossils inhabited are restricted to the Nama Group in Namibia (Germs, 1972;Seilacher, 1999; and the central region of the Iberian Peninsula (Vidal et al., 1994). ...
... There exists a prolific debate regarding taxonomic affinities of the Cloudina genus in the four decades of its study (Germs, 1972;Zaine and Fairchild, 1987;Grant, 1990; Conway Morris et al., 1990; Conway- Gaucher et al., 2003); B: Main lithostratigraphic units that occur in around the City of Corumbá (Modified after Lacerda Filho et al., 2004), indicating the sections of Itaú-Saladeiro (1), Laginha (2) and Corcal (3); and C: Simplified geologic map of Tocantis Province, highlighting the Paraguay Southern Belt (Modified after Pimentel et al., 2000;Hasui, 2012). Morris, 1993;Hua et al., 2003Hua et al., , 2005Adorno et al., 2017), including morphology (Grant, 1990;Seilacher, 1999;Adorno et al., 2017;Mehra and Maloof, 2018), mineralogy (Grant, 1990;Brain, 2001;Hua et al., 2005;Becker-Kerber et al., 2017), paleoecology (Germs, 1972;Grant, 1990;Seilacher, 1999;Hua et al., 2005;Cortijo et al., 2010;Becker-Kerber et al., 2017;Mehra and Maloof, 2018) taphonomy (Cortijo et al., 2010;Meira, 2011;Warren et al., 2012;Becker-Kerber et al., 2017Mehra and Maloof, 2018) and extinction (Brain, 2001;Hua et al., 2003;Becker-Kerber et al., 2017). In contrast, information about the sedimentary environment in which these fossils inhabited are restricted to the Nama Group in Namibia (Germs, 1972;Seilacher, 1999; and the central region of the Iberian Peninsula (Vidal et al., 1994). ...
Article
The Tamengo Formation corresponds to one of the most complete records of Ediacaran carbonate deposits in South America that contains Cloudina and Corumbella calcified exoskeletons macroscopic fossils. With the objective of characterizing its paleoenvironment, a total of ten sedimentary facies indicative of a carbonate platform were identified. In the outer ramp region there are massive mudstones, massive marl to claystones, and shales. In the mid-ramp there are facies that are storm-dominated with swaley/hummocky cross-stratified grainstone, tangential cross-bedding grainstone, massive bioclastic grainstone and massive marl to claystone. Lastly, in the inner ramp portion there are massive intraclastic grainstone, massive intraclastic rudstone, massive oolitic grainstone and laminate mudstone/shale rhythmite, and microbial textures are present at the base of the rhythmites, indicative of a back-ramp environment. Faciology data indicate that the Cloudinas inhabited a protected environment between oolitic bars in the inner ramp and back-ramp. These organisms were periodically transported and reworked by waves generated by storms in the mid-ramp and outer ramp zones. The positive values for δ13C in carbonates (1,5 to 5,4‰) and δ15N (between 3,5 and 4,5‰) of deposits with Cloudina indicate a marine paleoenvironment with shallow, hot, and oxygenated waters with a high productivity of organic matter. In this context, the facies analyses and stratigraphy, aided by C, O, and N isotopes from the Tamengo Formation in outcrops from the Corumbá regions in the southwest of Brazil allows for the reconstruction of an Ediacaran carbonate ramp and inferences about the habitat of Cloudina, thus increasing understanding of this important chapter of Earth history.
... Previous synonyms and diagnosis Adorno et al. (2017) stated that "Together with Cloudina lucianoi (Beurlen and Sommer, 1957), there are seven valid species of Cloudina Germs, 1972: Cloudina hartmanae Germs, 1972Cloudina riemkeae Germs, 1972;Cloudina waldei Hahn and Pflug, 1985; Cloudina lijiagouensis Zhang et al., 1992; Cloudina sinensis Zhang et al., 1992; and Cloudina carinata Cortijo et al., 2010 (Tab. 1)". ...
... We are not suggesting that Adorno et al. (2017) interpreted the morphology of Cloudina as not being composed of originally empty space between each layer. In fact, they even discuss these features for the Tamengo material: "In this way, it was observed that the layers have free space between them" (page 29 of Adorno et al., 2017). ...
... We are not suggesting that Adorno et al. (2017) interpreted the morphology of Cloudina as not being composed of originally empty space between each layer. In fact, they even discuss these features for the Tamengo material: "In this way, it was observed that the layers have free space between them" (page 29 of Adorno et al., 2017). However, the morphological terms "annular ridges" and "depressions" goes back to the original interpretation of Cloudina morphology. ...
... The former has a single wall and blunt cones that does not nest deep, whereas, the latter is multiwalled and has two forms α and β, with cones similar in appearance to those of C. hartmanae (Germs, 1972) (Fig. 5A, B, a, b). Morphologically C. hartmannae may be synonymous with both C. riemkeae (Grant, 1990;Hua et al., 2005;Cortijo et al., 2010) and C. lucianoi (Adorno et al., 2017) (Fig. 6d). Interestingly, an emended diagnosis of C. hartmanae was proposed by Cai et al. (2017) to accommodate Cloudina characterized by transverse and/or oblique annulations that fully occur on the exterior surface of the funnels. ...
... In addition, an overlap in diameter sizes can be found in C. waldei, C. lucianoi and C. hartmanae, this leaves open the question of whether it is suitable to use diameter sizes as the basis for separating species of Cloudina. Moreover, it is worth noting that the distinctiveness of C. hartmanae, C. riemkeae, C. lucianoi and C. waldei remains unclear, the pattern of overlap of funnel-with-funnel structure of C. riemkeae is also found in C. carinata, the interlamellar space found in C. carinata is exhibited by members of both C. locianoi and C. hartmanae (Adorno et al., 2017). In our study, Cloudina remains are calcified and have similar physical properties to those of the surrounding limestone matrix, this led us to make measurements and observations of isolated fossils on polished slabs and thin sections. ...
Article
Two index fossils Shaanxilithes ningqiangensis and Cloudina hartmannae are selected as potential candidates for the biostratigraphic marker of the Terminal Stage of the Ediacaran System (551-538 Ma) due to their relative wide distribution. Among these two candidates, the first appearance datum of C. hartmanae in the Dengying Formation in the Gaojiashan section, southern Shaanxi Province, China coincides with 5.8‰ positive excursion of carbon isotope compositions (δ¹³C). The relationship between Cloudina and a significant positive excursion of carbon isotope is also evident among different studied basins, such as those in Namibia, Oman and Brazil. Given its worldwide distribution and unparalleled significance in biological innovation, the biomineralized C. hartmannae has excellent potential to be the stratigraphic marker for defining the Terminal Ediacaran Stage, and can be correlated with precision to different paleocontinents.
... In Cloudina riemkeae the funnel-like elements are small and nested only shallowly [17]. The type specimen of Cloudina carinata were originally thought to occur in the terminal Ediacaran [26], but is now known to be basal Terreneuvian in age [27]. A particular morphological feature of Cl. carinata is its roughly eight-sided appearance assumed by longitudinal ridges on the outer surface (figure 1f ). ...
... 7A). The age of Membrillar olistostrome was originally described as Late Ediacaran [26], but is considered as the earliest Terreneuvian in the most recent study [27]. A smaller specimen was also reported from the terminal Ediacaran interval of the Villarta Formation of the Ibor Group, central Spain [38], but we believe that the smaller size makes it distinct from the types of this species from the Membrillar olistostrome. ...
Article
Full-text available
The Ediacaran–Cambrian transition and the following Cambrian Explosion are among the most fundamental events in the evolutionary history of animals. Understanding these events is enhanced when phylogenetic linkages can be established among animal fossils across this interval and their trait evolution monitored. Doing this is challenging because the fossil record of animal lineages that span this transition is sparse, preserved morphologies generally simple and lifestyles in the Ediacaran and Cambrian commonly quite different. Here, we identify derived characters linking some members of an enigmatic animal group, the cloudinids, which first appeared in the Late Ediacaran, to animals with cnidarian affinity from the Cambrian Series 2 and the Miaolingian. Accordingly, we present the first case of an animal lineage represented in the Ediacaran that endured and diversified successfully throughout the Cambrian Explosion by embellishing its overall robustness and structural complexity. Among other features, dichotomous branching, present in some early cloudinids, compares closely with a cnidarian asexual reproduction mode. Tracking this morphological change from Late Ediacaran to the Miaolingian provides a unique glimpse into how a primeval animal group responded during the Cambrian Explosion.
... The Ediacaran Tamengo Formation exhibits paleontological remains with metazoan fossils such as Corumbella werneri (Pacheco et al., 2015;Walde et al., 2019), Cloudina sp. (Adorno et al., 2017;Becker-Kerber et al., 2017), Paraconularia sp. (Van Iten et al., 2014), and trace fossils such as Multina minima (Parry et al., 2017). ...
Article
Full-text available
The Tamengo Formation (Corumbá Group) is an important Ediacaran stratigraphic unit in South America due to the presence of metazoan fossils and geochemistry data of carbonate rocks, with excellent geochronological delimitation (between 555–541 Ma) obtained by U–Pb dating on volcanic zircons. The present work shows three new species of macroalgae found as carbonaceous compressions and studied for their morphology and taxonomy. All new taxa are characterized as centric macroalgae; Tamengophyton espinosa sp. nov. is a fan-shaped alga with striated thalli, dichotomous branches, trichomes with perpendicular growth, and a connecting membrane. Ladariella hidria sp. nov. is formed by a set of striated and branched thalli in a cylindrical form with almond-shaped structures in the top. Ladariophyton veinosa sp. nov. is characterized by the main growth thallus and an enlarged longitudinal structure at the center. These new occurrences of macroalgae add to the largest life assemblages in the Neoproterozoic of South America, which contributes to documentation of the evolutionary history of macroalgae and the paleoecological settings of the Late Ediacaran.
... The integration of the information regarding the taxonomy and stratigraphic distribution of the above-reported species was presented as a biostratigraphic essay composed of seven biozones, respectively named, from base to top: Cloudina Assemblage Superzone that is distributed in all 15 analyzed sections. There are three biozones inserted in this superzone distributed in sections of Brazil and Paraguay: Cloudina lucianoi/Corumbella werneri Interval Zone; Corumbella werneri Range Zone; and Corumbellla werneri/Cloudina lucianoi Interval Zone ( Adôrno et al., 2016Adôrno et al., , 2017. It was possible to propose two subzones: Bavlinella faveolataLeiosphaeridia minutissima Assemblage Subzone inserted in the basal part of Corumbella werneri Range Zone and Vendotaenia antiqua-Cloudina lucianoi Concurrent-Range Subzone at the upper portion of the Corumbella werneri/Cloudina lucianoi Interval Zone. ...
Article
Full-text available
Se presenta en este trabajo el análisis paleontológico de 26 especies fósiles muestradas en cinco cortes de las Formaciones de Tamengo y Guaicurus en las regines de Corumbá y Ladário: canteras de Corcal y Laginha, Porto Sobramil, Porto Figueiras y Ecoparque Cacimba. Además, se añaden varias interpretaciones paleoecológicas y ambientales, basadas en el registro fósil. Cloudina carinata Cortijo et al., 2010, previamente citada en España y Siberia, aparece por primera vez en el continente Americano, concretamente en limolitas de la Formación Tamengo en el corte de Porto Figueiras, Corumbá, Estado de Mato Grosso do Sul, Brasil. La biota de la Formación Tamengo incluye tres metazoos mineralizados, que incluyen espículas de poríferos, posibles gémulas de esponjas y una colonia sésil de procaiotas epibentónicos. Este trabajo se centra en la taxonomía y distribución estratigráfica de cuatro icnoespecies y tres especies de vendoténidos que forman la fauna bentónica de la parte superior del Grupo de Corumbá. La biodiversidad de la Formación Tamengo ha sido completada con el registro de 16 especies microfósiles que representan posiblemente una asociación plantónica marina. Se ha identificado un cambio drástico en las condiciones ambientales de las Formaciones Tamengo y Guaicurus, que culminan en un evento de extincinón masiva posiblemente relacionado con la extincición en masa que marca el tránsito global Ediácarico- Cámbrico. Por otro lado, se han extraído microfósiles de pared orgánica de varios afloramientos: nueve especies de la Formación de Nomtsas (Namibia), cuatro de la Formación Tagatiya Guazu (Paraguay) y seis de la Formación Dengying (China). Se propone un marco bioestratigráfico para el Ediacárico terminal que incluye seis biozonas y una biozona para el Cámbrico basal.
... Beds do not correlate between the outcrops because the uppermost section is missing at 'Sobramil'; contact between the Tamengo and Guiacurus formations is exposed at 'Corcal'. Stratigraphical sections are adapted from Walde et al. (2015) and Adorno et al. (2017). Sinotubulites. ...
Article
Walde, D.H.-G., Weber, B., Erdtmann, B.-D. & Steiner, M. 20 June 2019. Taphonomy of Corumbella werneri from the Ediacaran of Brazil: sinotubulitid tube or conulariid test? Alcheringa 43, 335–350. ISSN 0311-5518 The problematic late Ediacaran tubular fossil Corumbella werneri is revised based on two-dimensional compressions, and new three-dimensionally preserved specimens from the Tamengo Formation of the Corumbá Region in Mato Grosso do Sul, west-central Brazil. These fossils represent some of the oldest skeletonized metazoans and were originally described from diagenetically compacted tubes that prompted conflicting interpretations as either Ediacaran coronate scyphozoan exoskeletons, or conulariid tests. Our new material from Corumbá permits a morphological and taphonomic revision of C. werneri, which we suggest was probably a calcareous sinotubulitid. Corumbella werneri closely resembles the late Ediacaran Sinotubulites from South China, as well as the Silurian worm tube Eoalvinellodes, which has similar exterior ornamentation. Ultrastructurally, the tubes of C. werneri exhibit a coarse sparitic microtexture, which we attribute to diagenetic alteration. Partial flexibility also supports interpretation as an originally weakly calcified, or entirely organic exoskeleton. We therefore reject placement of C. werneri as a conulariid scyphozoan, and instead, advocate possible relationships with marine annelids. Detlef Hans-Gert Walde [walde.detlef@gmail.com], University of Brasília, Institute of Geosciences, Brasília-DF, Brazil; Bernd Weber [bweber@zedat.fu-berlin.de], Freie Universität Berlin, Institut für Geologische Wissenschaften, Malteserstr. 74–100, D-12249 Berlin, Germany; Bernd-D. Erdtmann [berni1739@gmail.com], 1165 N Mountain View Road, Apache Junction, AZ 85119, USA; *Michael Steiner [Michael.Steiner@FU-Berlin.de], Freie Universität Berlin, Institut für Geologische Wissenschaften (Haus D), Malteserstr. 74–100, D-12249 Berlin, Germany.
... The unit is truncated at the top by a regional erosional unconformity ( Figure 1B), overlain by polymictic breccia having clasts of crystalline basement, dolostone and phosphorite at the base of the Tamengo Formation (Gaucher et al., 2003;Campanha et al., 2011;Amorim et al., 2020). The overlying Tamengo Formation was deposited in a shallow to relatively deep storm-influenced carbonate ramp, as interpreted from cross-bedded fine grainstones, mudstones and shales associated with metazoan fossils and meiofaunal trace fossils (Zaine and Fairchild, 1987;Gaucher et al., 2003;Van Iten et al., 2014;Pacheco et al., 2015;Adorno et al., 2017;Parry et al., 2017;Amorim et al., 2020). ...
Article
Full-text available
Acritarchs, a polyphyletic group of acid-resistant organic-walled microfossils, dominate the eukaryotic microfossil record in the Proterozoic (2500–541 Ma) yet exhibit significant reduction in diversity and size at the transition to the Phanerozoic (541–520 Ma). Despite the difficulty of tracing phylogenetic relationships among acritarchs, changes in their complexity and diversity through time have allowed their use in paleoecological and biostratigraphic schemes. The Doushantuo-Pertatataka Ediacaran acritarch assemblage, for example, is usually considered as restricted to the early Ediacaran between 635 and 580 Ma. But similar, diverse acritarchs have been recovered from younger rocks in Mongolia and Arctic Siberia and are now reported here from phosphatized horizons of the upper Bocaina Formation (ca. 555 Ma), Corumbá Group, SW Brazil. In the overlying black limestones and shales of the latest Ediacaran Tamengo Formation (542 Ma) acritarch diversity is low, but the skeletal metazoans Cloudina and Corumbella are abundant. The Bocaina acritarch assemblage shares forms referable to the genera Leiosphaeridia, Tanarium, Asseserium and Megasphaera with the Doushantuo-Pertatataka assemblage, but also includes specimens similar to the Phanerozoic genus Archaeodiscina in addition to two new complex acritarchs. The first is covered by rounded low conical bumps, similar to Eotylotopalla but differs in having a distinct opening suggestive of greater (multicellular?) complexity. The second, identified here as Morphotype 1, is a double-walled acanthomorph acritarch with scattered cylindrical processes between the walls. The contrast in acritarch diversity and abundance between the Bocaina and Tamengo formations is likely due in part to paleoenvironmental and taphonomic differences (absence of the phosphatization window in the latter), as well as to the appearance of both suspension-feeding skeletal metazoans (Cloudina and Corumbella). The occurrence of Doushantuo-Pertatataka acritarchs in SW Brazil, northern Mongolia, and Arctic Siberia extend the biostratigraphic range of this assemblage up to the terminal Ediacaran Cloudina biozone.
... This would serve to increase the stability of the tube as it grew larger, helping it maintain an upright orientation and elevating its apertural end for feeding purposes. The sharp changes in growth direction observed on some specimens may indicate rejuvenation from partial burial or event sedimentation that had knocked the tube overeffectively righting the tube back to a vertical positionsimilar to that inferred from C. hemiannulatus (Cai et al. 2011 (Taylor 1966;Mount et al. 1983;Signor et al. 1983Signor et al. , 1987Smith et al. 2016Smith et al. , 2017, Namibia (Germs 1972;Grant 1990;Grotzinger et al. 2000), Kazakhstan (Yang et al. 2016), Spain (Cortijo et al. 2010;Zhuravlev et al. 2012), Oman (Conway ), Brazil (Walde et al. 2015;Adorno et al. 2017), the East European platform (Gnilovskaya 1996;Sokolov 1965Sokolov , 1967, the Siberian platform (Kontorovich et al. 2009;Terleev et al. 2011;Zhuravlev et al. 2012), and Paraguay (Warren et al. 2011(Warren et al. , 2017, among other localities (see summary in Cai et al. 2017). Viewing the palaeogeographical distribution of the currently recognized cloudinomorph sites (Fig. 10, reconstructed from G-Plates), the Nevada localities examined here sat on the northern shelf margin of Laurentia and are definitively tropical. ...
Article
Owing to their temporal position during the decline of the classic Ediacara biota and the appearance of the more recognizable metazoans of the Cambrian Period, the terminal Ediacaran (∼551–539 Ma) assemblages of tubular fossil forms hold potential to improve understanding of biotic turnover near the end of the Ediacaran Period. Cloudinid taxa, including the terminal Ediacaran index fossil Cloudina, are the most well studied of these Ediacaran tubular forms due to their global palaeogeographical distribution. Recent reports revealed ecosystems of tubicolous organisms from the Great Basin region, Nevada, USA, and assigned taxa to such genera as Conotubus, Gaojiashania and Wutubus, well known from contemporaneous Chinese deposits. Appreciating the role that these organisms may have played in the evolutionary history of metazoans and recognizing their potential global distribution, however, requires careful taxonomic study. Here, we detail pyritized fossils from the Deep Spring and Wood Canyon formations of Esmeralda and Nye counties, Nevada, USA, respectively. Our investigation focused on the most abundant tubular taxon from the Nevada sites, which was previously generically assigned to Conotubus. While outwardly similar in morphology to this Gaojiashan taxon, our investigation determines that those fossils previously figured as Conotubus are instead two distinct taxa. The first represents a new species of Saarina – Saarina hagadorni sp. nov. – a genus previously known only from the East European platform, and the second is established as a novel genus and species, Costatubus bibendi gen. et sp. nov. http://zoobank.org/urn:lsid:zoobank.org:pub:CC391194-FF96-4BDF-B9B2-E4361DA64A5B
... The Tamengo Formation in Southern Paraguay Belt (West Brazil) display carbonate rocks bearing Cloudina lucianoi (Zaine & Fairchild, 1987;Babcock, et al., 2005;Becker-Kerber et al., 2017;Adorno et al., 2017). Sr concentrations in these rocks are as high as 10000 μg/g (Boggiani et al., 2010) and evidence for authigenic early diagenetic aragonite cement is observed (Amorin et al., in review). ...
... The Tamengo Formation in Southern Paraguay Belt (West Brazil) display carbonate rocks bearing Cloudina lucianoi (Zaine & Fairchild, 1987;Babcock, et al., 2005;Becker-Kerber et al., 2017;Adorno et al., 2017). Sr concentrations in these rocks are as high as 10000 μg/g (Boggiani et al., 2010) and evidence for authigenic early diagenetic aragonite cement is observed (Amorin et al., in review). ...
... Cloudina species have wide geographic distribution reported from Namibia (Grant, 1990), Oman (Conway Morris et al., 1990) , South China (Hua et al., 2005;Cai et al., 2013;Cortijo et al., 2015), Spain (Cortijo et al., 2010(Cortijo et al., , 2015, Siberia (Terleev et al., 2011;Kontorovich et al., 2008); Mexico (Sour-Tovar et al., 2007), Brazil (Adôrno et al., 2017), Argentina and Uruguay (Gaucher et al., 2006), Canada (Hofmann & Mountjoy, 2001), Paraguay (Warren et al., 2011(Warren et al., , 2013(Warren et al., , 2014(Warren et al., , 2017(Warren et al., , 2019 and the USA (Grant, 1990;Zhuravlev et al., 2012). ...
Article
Full-text available
Se documenta en este resumen la primera aparición de Cloudina carinata Cortijo et al., 2010 en el continente americano. Esta nueva aparición extiende la distribución geográfica de esta especie, hasta ahora restringida a España y Siberia. Se presenta por primera vez en la Formación de Tamengo (Corumbá, Estado de Mato Grosso do Sul, Brasil) la asociación de metazoos mineralizados compuesta por Cloudina carinata, Cloudina lucianoi (Beurlen & Sommer, 1957) y Corumbella werneri Hahn et al., 1982. Esta asociación podría ser útil como marcador bioestratigráfico en las correlaciones internacionales del Ediacárico terminal, así como para futuras reconstrucciones paleobiogeográficas y paleoecológicas.
... In the Corumb a region (Fig. 1B), the Tamengo Formation comprises black shales, mudstones, wackestones, packstones and grainstones that represent a mixed carbonate-siliciclastic ramp influenced by storm events. The Ediacaran fossil assemblages reported for this unit include Corumbella werneri, Cloudina lucianoi (Zaine & Fairchild, 1987;Grant, 1990;Babcock et al., 2005;Pacheco et al., 2011Pacheco et al., , 2015Adorno et al., 2017;Becker-Kerber et al., 2017), vendotaenids and conulariids (Van Iten et al., 2014, and meiofaunal ichnofossils (Parry et al., 2017). According to Boggiani et al. (2010), a polymictic breccia marks the basal contact of the Tamengo Formation with the dolomite-rich stromatolite beds of the Bocaina Formation. ...
Article
Full-text available
Mixed carbonate–siliciclastic deposits of the Tamengo Formation (terminal Ediacaran), record the rise of calcifying metazoans and the origin of exoskeletons in animals. To explore the relationships between environmental setting and the first appearance of calcified metazoans and their ecology, this study presents detailed sedimentological and stratigraphic data of eight sections that capture the final stages of the Ediacaran (550 to 543 Ma). This study combines stratigraphic characterization with detailed facies descriptions and evaluates lateral heterogeneity and overall ramp sedimentation integrated with fossil distribution. The Tamengo Formation represents a storm‐dominated ramp. The outer to mid‐ramp is composed of very fine‐grained siliciclastic rocks containing Corumbella body fossils and thin‐bedded mudstone/wackestone containing Cloudina. The mid‐inner ramp is dominated by wackestone/packstone with abundant Cloudina skeletal debris and ooid packstone/grainstone shoal deposits. Locally, fragments of Corumbella and Cloudina are found on the same horizon, which is a result of their high accumulation rate, resulting from the reworking and mixing of epifaunal organisms. In spite of taphonomic biases, the general distribution of Corumbella and Cloudina across the unit suggests that these organisms have been transported across ramp and/or probably show a differential response of fauna preservation. When compared to other occurrences worldwide, this dataset indicates an already complex ecosystem in the Ediacaran, where these early animals were capable of adapting to specific environmental niches.
Article
Full-text available
The Corumbá Group is a Neoproterozoic succession of terrigenous and carbonate sedimentary rocks located at the southern Paraguay Belt, central Brazil. The upper units of the Corumbá Group include the Ediacaran carbonate Bocaina and Tamengo formations, whose limit is characterized by polymictic breccias recognized in several sites from Corumbá to Serra da Bodoquena, Mato Grosso do Sul. Despite the widespread occurrence, the breccias are poorly described and their origin is uncertain. The aim of this study is to present the differences between sedimentary and tectonic breccias of the Corumbá Group and propose a genesis model for each. The sedimentary breccias comprise mainly matrix-supported chaotic facies that formed by submarine mass flows on slope aprons. Sea level fall and/or increased faulting rates exposed the underlying units and triggered the gravity fluxes by creating a steep slope. The base of the sedimentary breccia represents a major unconformity within the carbonate sedimentation of the Corumbá Group, with potential correlation to other Ediacaran units. The subsequent development of the Paraguay fold-thrust belt caused the formation of tectonic breccias in reverse fault zones. Cataclasis and mylonitization deformed the dolomitic host rock by fracturing and produced a fine foliated matrix.
Article
The interest in geoparks in Brazil began after the inclusion of the Araripe Geopark into the Global Geopark Network (GGN) in 2006. After that, several areas within Brazil were proposed as potential geoparks, two of which were then formalized—the Quadrilatero Ferrífero (Minas Gerais) and Bodoquena-Pantanal (Mato Grosso do Sul), and formal applications were submitted to GGN in 2010 but not accepted. In spite of the relevance in the geology and paleontology of both areas, the refusals were due to being only a project and not an actual functioning structured geopark yet working. No kind of inventory or quantification of the geological sites was carried out to both of the proposed geoparks. Furthermore, the purpose of the present work is to present an inventory of the sites of the area proposed for the Geopark Bodoquena-Pantanal (GBP) in an effort to demonstrate the significance of the geological heritage of the area. The area of the GBP includes Ediacaran animal fossils, which provide information about the geological record just before the Cambrian Explosion. This record created international interest in the area, together with sections with that record of global changes that characterized the end of the Neoproterozoic Eon, such as the iron formations of the Urucum Massif (Rapitan type) and Marinoan glacial sediments and limestone (Tamengo Formation). The present inventory was compiled by the GEOSSIT platform of the Geological Survey of Brazil (CPRM), which is based on the method of Brilha (2016), with modifications. The 51 sites investigated were distributed among 6 geological frameworks, defined to represent the geological history of the region, and 26 sites were considered as geosites, of which 12 present international relevance, specifically the sites of Corumbá Group, due to the importance for the investigation of the Ediacaran period. The inventory and its numerical result show the scientific importance of the area, as already recognized by international meetings and publications on the geology, and is useful to future plan and revision of the proposed geopark.
Article
Full-text available
Building bridges between environmental and political agendas is essential nowadays in face of the increasing human pressure on natural environments, including wetlands. Wetlands provide critical ecosystem services for humanity and can generate a considerable direct or indirect income to the local communities. To meet many of the sustainable development goals, we need to move our trajectory from the current environmental destructive development to a wiser wetland use. The current article contain a proposed agenda for the Pantanal aiming the improvement of public policy for conservation in the Pantanal, one of the largest, most diverse, and continuous inland wetland in the world. We suggest and discuss a list of 11 essential interfaces between science, policy, and development in region linked to the proposed agenda. We believe that a functional science network can booster the collaborative capability to generate creative ideas and solutions to address the big challenges faced by the Pantanal wetland.
Article
Full-text available
Building bridges between environmental and political agendas is essential nowadays in face of the increasing human pressure on natural environments, including wetlands. Wetlands provide critical ecosystem services for humanity, and can generate a considerable direct or indirect income to the local communities. In order to meet many of the sustainable development goals, we need to move our trajectory from the current environmental destructive development to a wiser wetland use. The current paper contain a proposed agenda for the Pantanal aiming the improvement of public policy for conservation in the Pantanal, one of the largest, most diverse, and continuous inland wetland in the world. We suggest and discuss a list of 10 essential interfaces between science, policy, and development in region linked to the proposed agenda. We believe that a functional science network can booster the collaborative capability to generate creative ideas and solutions to address the big challenges faced by the Pantanal wetland.
Article
Full-text available
is unit a critical target for recent paleobiological, biostratigraphic, chemostratigraphic, and geochronological investigation (Pacheco and Leme, 2011; Spangenberg et al., 2014; Pacheco et al., 2015; Walde et al., 2015; Adôrno et al., 2017; Becker-Kerber et al., 2017). Importantly, the recently reported chemostratigraphic data and radiometric ages from the Tamengo and overlying Guaicurus formations provide key age constraints on the stratigraphic range of Corumbella werneri and Cloudina lucianoi (Boggiani et al., 2010; Parry et al., 2017). Thus, the Corumbá Group will likely play an important role in the establishment of the Terminal Ediacaran Stage (Xiao et al., 2016). Following a successful field workshop on the Corumbá Group in 2013 (Kaufman et al., 2014), the reports of species attributed to Corum- bella and Cloudina in the Bambuí and Itapucumi groups (Warren et al., 2011; Warren et al., 2014) prompted new interest in the Corumbá Group. In response to this renewed interest, Dermeval Do Carmo, Detlef Walde, Adalene Moreira Silva at University of Brasilia and Aguinaldo Silva at University of Mato Grosso do Sul organized a field workshop to examine the Corumbá Group on July 12–16, 2017. The workshop drew 16 participants from University of Brasília, Univer- sity of São Paulo, Federal University of Mato Grosso do Sul, Univer- sidade Estadual Paulista, Geopark of the Bodoquena-Pantanal, and Virginia Tech (Fig. 5).
Article
The index ichnofossil Treptichnus pedum Seilacher 1955 and four types of Microbially Induced Sedimentary Structures (MISS) - variants of wrinkle and elephant skin structures – are the first fossils described from the Três Marias Formation, topmost unit of the Bambuí Group of south-central Brazil. Despite the stratigraphic importance and widespread occurrence of this unit in the São Francisco Craton and adjacent Brasília Fold Belt, its age is still poorly constrained between the Neoproterozoic and Early Paleozoic. This discovery is significant because the first appearance datum (FAD) of T. pedum has been used to define the Ediacaran-Cambrian boundary. Hence, the presence of T. pedum indicates an early Paleozoic age for the uppermost Bambuí Group and means that the Ediacaran-Cambrian limit must lie deeper in the Bambuí Group, somewhere between this level and that of the terminal Ediacaran index-fossil Cloudina sp. in the Sete Lagoas Formation, near the base of the group. Available age determinations on detrital zircon grains and chemostratigraphic correlations are consistent with an Ediacaran to Cambrian age for this group. Detailed paleontological prospection throughout the group may now proceed within a better constrained time frame and hopefully reveal additional fossil evidence of Cambrian as well as Ediacaran life in the Bambuí Group.
Chapter
The Ediacaran Period (635–538 Ma) has the longest duration among all stratigraphically defined geological periods. The basal boundary of the Ediacaran System is defined by a horizon near the base of the Nuccaleena Formation overlying the Cryogenian diamictite of the Elatina Formation at the Enorama Creek section in South Australia. Most Ediacaran fossils represent soft-bodied organisms and their preservation is affected by taphonomic biases. Thus the Phanerozoic approach of defining stratigraphic boundaries using the first appearance datum of widely distributed, rapidly evolving, easily recognizable, and readily preservable species would have limited success in the Ediacaran System. The subdivision and correlation of the Ediacaran System must therefore be founded on a holistic approach integrating biostratigraphic, chemostratigraphic, paleoclimatic and geochronometric data, particularly carbon and strontium isotopes, glacial diamictites, acanthomorphic acritarchs, Ediacara-type megafossils, and certain tubular fossils. Our preferred scheme is to divide the Ediacaran System into two series separated by the 580 Ma Gaskiers glaciation. Stage-level subdivisions at the bottom and top of the Ediacaran System, including the definition of the second Ediacaran stage (SES) and the terminal Ediacaran stage (TES), are feasible in the near future. Additional Ediacaran stages between the SES and TES can be envisioned, but formal definition of these stages are not possible until various stratigraphic markers are thoroughly tested and calibrated at both regional and global scales.
Article
The arrival of animals with hard parts at the end of the Ediacaran Period was an important evolutionary innovation. Biomineralized structures serve a number of biological functions and pose environmental challenges. Those same hard parts that once played a role in living organisms also affect their postmortem histories. Taphonomic scenarios may create biases that can impact perceptions on the systematic, morphological, biostratigraphic, and paleogeographic patterns in the fossil record. This is well exemplified by the taxonomic controversies regarding Cloudina, the most geographically widespread and abundant shelly fossil of the uppermost Ediacaran. In this study, we discuss new taphonomic data on Cloudina-bearing strata deposits from the Tamengo Formation (Corumbá Group, Brazil) and how influential this taphonomy is on a robust taxonomy of this fossil. Our observations suggest that allochthonous Cloudina deposits from the Tamengo Formation present evidence of taphonomic influences on the transporting/reworking of fragmentation and disarticulation of Cloudina tubes. Differences in size distributions between some of the localities have demonstrated that this trait is not reliable for defining or synonymizing species of Cloudina, and these differences probably reflect a myriad of taphonomic and paleobiological phenomena. Moreover, in some outcrops of the Tamengo Formation, shell walls are usually poorly preserved due to plastic deformations and diagenetic dissolution/recrystallization processes, which conceal morphological diagnostic features used in Cloudina taxonomy. Similar taphonomic biases may be of equal importance to the taxonomy of Cloudina preserved in other upper Ediacaran carbonates. Hence, earlier claims in favor of the synonymization of Cloudina species from the Tamengo Formation cannot currently be justified.
Article
Full-text available
The western region of the southern Pantanal is characterised by soils with high phosphorus (P) contents, derived from materials from the surrounding lithostratigraphic units, accumulated by fluvial transport. However, studies on forms and availability of P in these soils are scarce. The objective of this study was to evaluate the different forms of inorganic P and their relationship with some attributes of carbonatic soils in the Pantanal of Mato Grosso do Sul, Brazil. Hedley’s sequential fractionation scheme was used to evaluate the forms of P in soil profiles: Kastanozems (profiles P1 and P3) and Gleysol (profile P2). Total P contents were similar in the three profiles, 3782–5637 mg kg–1, with mean values of 22% for organic P and 46% for inorganic P (P.i). The P.i results indicated that in the profiles there was a predominance of inorganic forms of P in the following order: P-NaOH 0.5 mol L–1 > P-NaHCO3 > P-NaOH 0.1 mol L–1 > P-HCl, that is, adsorbed to microaggregates, labile, adsorbed to oxides and precipitated with calcium (Ca), respectively. The highest values of total organic P were verified in the surface horizons, with high correlation with total P contents. Residual P contents were high in all profiles, representing 29.0–33.3% of the total P, being correlated with CaCO3 contents. The studied profiles had high contents of labile P, with the highest values in the fraction P.i-NaHCO3, possibly associated with the processes of reduction of iron during the periods of floods, making the adsorbed P available. The contents of P.i-NaOH 0.1 mol L–1, a moderately labile fraction adsorbed to oxides, showed few differences compared to the non-labile fractions associated with Ca (P.i-HCl). Possibly, organic matter was bound to Ca, inhibiting the formation of precipitates of Ca with P and making P available for the more labile fractions.
Article
Full-text available
The Ediacaran-Cambrian transition, which incorporates the radiation of animals, lacks a robust global temporal and spatial framework, resulting in major uncertainty in the evolutionary dynamics of this critical radiation and its relationship to changes in palaeoenvironmental geochemistry. We first present a new δ¹³Ccarb composite reference curve for the Ediacaran Nama Group of southern Namibia, and we then outline four new possible global age models (A to D) for the interval 551–517 million years ago (Ma). These models comprise composite carbonate‑carbon isotope (δ¹³Ccarb) curves, which are anchored to radiometric ages and consistent with strontium isotope chemostratigraphy, and are used to calibrate metazoan distribution in space and time. These models differ most prominently in the temporal position of the basal Cambrian negative δ¹³Ccarb excursion (BACE). Regions that host the most complete records show that the BACE nadir always predates the Ediacaran-Cambrian boundary as defined by the first appearance datum (FAD) of the ichnospecies Treptichnus pedum. Whilst treptichnid traces are present in the late Ediacaran fossil record, the FAD of the ichnospecies T. pedum appears to post-date the LAD of in situ Cloudina and Namacalathus in all environments with high-resolution δ¹³Ccarb data. Two age models (A and B) place the BACE within the Ediacaran, and yield an age of ~538.8 Ma for the Ediacaran-Cambrian boundary; however models C and D appear to be the most parsimonious and may support a recalibration of the boundary age by up to 3 Myr younger. All age models reveal a previously underappreciated degree of variability in the terminal Ediacaran, incorporating notable positive and negative excursions that precede the BACE. Nothwithstanding remaining uncertainties in chemostratigraphic correlation, all models support a pre-BACE first appearance of Cambrian-type shelly fossils in Siberia and possibly South China, and show that the Ediacaran-Cambrian transition was a protracted interval represented by a series of successive radiations. The Ediacaran-Cambrian radiation occurred over a protracted interval without global mass extinctions and with generally diachronous metazoan appearances.
Article
Full-text available
This study aims to update the knowledge about the importance of the late Ediacaran fossil record and geochemical data from Corumbá, State of Mato Grosso do Sul, at the Brazilian-Bolivian border. The Corumbá graben system is located near a triple junction developed above a hot spot of two young (545-480 Ma) Brasiliano provinces: the mostly Bolivian Chiquitos-Tucavaca aulacogen which cuts across the Amazon Craton/Rio Apa Block, and Paraguay Fold Belt. The Neoproterozoic sedimentary cover of South Paraguay Belt starts with the metasediments, diamictites and iron formation of the Jacadigo Group, now related to an end-Cryogenian age. Most remarkable geochemical and paleontological data come from the overlying Corumbá group, mainly from the dolostones with stromatolites of the Bocaina Formation, and limestones with shale and silty intercalations at this group's upper part, in the Tamengo Formation. This last unit contains a fossil assemblage correlated to late Ediacaran fauna. This fauna contains originally substrate-emergent tube-like Corumbella werneri, Cloudina lucianoi and microfossils. Furthermore, the fossils from the Corumbá Group in Brazil and Paraguay represent the most important witnesses for the occurrence of late Ediacaran fossils close to the basal Cambrian boundary in South America. Therefore, the Corumbá region is significant for paleogeographical reasons and, on the other hand, allows insights into the evolution of the oldest skeletonized metazoans. After new research results, the high degree of similarity of the geological facies evolution with other parts of the world (e.g. Yangtze Platform/Southern China, Siberia, Spain and Namíbia) can be demonstrated, where the fragmentation of the Rodinia super-continent and Neoproterozoic glaciations are also well-documented. The sharp top contact of the shallow marine Tamengo Formation with the laminated black shales (containing rare angular dropstones) of the discordantly overlying Guaicurus Formation indicates that the latter represents a new transgressive glacially influenced marine onlap succession. A Cambrian age of the Guaicurus Shales is not (yet) biostratigraphically verified, however, the underlying fossil record of cloudinids indicates a terminal Ediacaran age for the top of the Tamengo Formation. The microtubular cloudinids are interpreted as dysoxic analogues of recent tubeworms and are suggested to serve as first skeletonized worldwide "index fossils" to delineate the onset of a Phanerozoic-type body fossil vectorial evolutionary pathway. Based on the FAD of cloudinids as marker fossils, a revision of the Precambrian/Cambrian boundary is here advocated. This would avoid placing this important GSSP into the virtually worldwide Nomtsas-Baykonurian glacial hiatus.
Article
Full-text available
BRAS1LIANO TECTONIC EVOLUTION OF THE PARAGUAY BELT: THE STRUCTURAL DEVELOPMENT OF THE CUIABÁ REGION. Late Proterozoic sediments and metasediments are present along the tranS1tion zone between the Amazonian Craton to the northwest and the Paraguay Belt to the southeast in the Cuiabá region, Mato Grosso. In the Paraguay Belt, these rocks have been affected by the BraS1liano Orogeny, characterized by increaS1ng deformation and metamorphism from the craton towards the fold belt The metamorphic evolution is determined by the illite crystallinity index. Four closely related phases of deformation (D1 to D4) are distinguished in the Paraguay Belt. The trend directions of Dl, D2 and D3 are almost identical (NE-SW) whereas D4 is transverse (NW-SE). The first phase Dl is the most preeminent, and is contemporaneous with the regional metamorphism. It produced tight and isoclinal Fl folds to the east and open folds F1 to the west, and associated S1 cleavage. The D2 and D3 phase conS1st mainly of local crenulation cleavages (S2 and S3). D4 phase is characterized by regional slight transverse folds. RESUMO Sedimentos e metassedimentos do Proterozóico Superior estão presentes ao longo da zona de tranS1ção entre o Cráton Amazônico à noroeste e a Faixa Paraguai, a sudeste, na região de Cuiabá, Mato Grosso. Na Faixa Paraguai, as rochas foram afetadas pela Orogênese Brasiliana que apresenta características de aumento da deformação e do metamorfismo da região cratônica em direção a faixa dobrada. A evolução metamórfica foi determinada pelos índices de cristalinidade da illita. Quatro episódios sucessivos de deformação progressiva (D1 a D4) são identificados na faixa. As três primeiras fases (D1 a D3) são quase co-axiais com direção NE-SW, enquanto a fase D4 é transversal (NW-SE). A primeira fase D1 é a mais proeminente, e contemporânea com o metamorfismo regional. Ela inclui dobras fechadas e isoclinais (sudeste) a dobras abertas (noroeste) com associada clivagem S1. As fases D2 e D3 estão representadas principalmente por uma clivagem de crenulação de caráter local (S2 e S3). A fase D4 é caracterizada por amplos dobramentos regionais. Palavras-chave: Orogênese BraS1liana, Geologia Estrutural, Mato Grosso, Faixa Paraguai.
Article
Full-text available
Terra Nova, 23, 382–389, 2011 An in situ assemblage of Cloudina, thrombolites and an ichnofossil (cf. Archaeonassa), together with fragments of Corumbella werneri, is reported here, from a tidally influenced, shallow, lagoonal setting on a carbonate ramp within the Itapucumi Group, Paraguay. The association of Cloudina with thrombolites is comparable to other terminal Neoproterozoic occurrences, but the coexistence of shelly fossils in situ with trace fossils and microbially induced sedimentary structures is apparently unique. This discovery extends the record of Cloudina and Corumbella in South America and further elucidates the diversity, distribution and palaeoecology of shelled organisms in late Ediacaran time.
Article
Full-text available
The emergence of soft-bodied metazoans and the radiation of the earliest skeletal organisms substantially changed the ecological dynamics of Ediacaran environments, leading to the genesis of biogenic hard-part deposits for the first time in Earth's history. The impact of bioclast origin on sedimentary processes is analyzed herein, focusing on the sedimentology and taphonomy of shell concentrations dominated by the Ediacaran index fossil Cloudina from the Itapucumi Group, Paraguay. Skeletal concentrations include both dense accumulations of parautochthonous, disarticulated specimens ("Type 1 deposits") and in situ specimens preserved as loosely packed assemblages ("Type 2 deposits"). At that time, Cloudina was the critical source of durable biomineralized hard parts in an environment nearly free of other bioclasts. The simple fabric and geometry of these accumulations are typical of Cambrian-style shell beds. Despite their Precambrian age, these deposits indicate that the establishment of the Phanerozoic style of marine substrates and preservation in early shell beds was determined more by the acquisition of hard parts than by environmental changes.
Article
Full-text available
Ediacaran fossils from the southwestern Great Basin may help constrain regional Vendian-Cambrian biostratigraphy and provide biogeographic links between facies in this region and elsewhere. Locally, trace fossils suggest the Vendian-Cambrian boundary occurs within or below the upper third of the lower member of the Wood Canyon Formation. Ediacaran soft-bodied and tubular fossils, including the frondlike fossil Swartpuntia and tubular, mineralized or agglutinated fossils similar to Archaeichnium, Cloudina, Corumbella, and Onuphionella occur in the lowermost Wood Canyon Formation. Discoidal forms referred to Nimbia occur in both the lowermost Wood Canyon Formation and the underlying strata of the Stirling Quartzite. These fossils occur directly below Lower Cambrian trace fossils, including Treptichnus pedum, and confirm the persistence of the Ediacaran biota to near the base of the Cambrian. These faunas may also help strengthen previously proposed correlation schemes between the two main facies belts of the southwestern Great Basin (the Death Valley and White-Inyo facies), because a nearly identical Vendian-lowest Cambrian succession of faunas occurs in both regions. Lastly, lack of cosmopolitan Ediacaran faunas in these strata suggests a paleobiogeographic link between the southwestern U.S. and southern Africa in Vendian time.
Article
Full-text available
The tubular fossil Cloudina is emerging as an important Ediacaran index fossil. However, its morphology, skeletogenesis, reproduction, and phylogenetic affinity have not been fully resolved. New material from the Dengying Formation of south China confirms that Cloudina tubes consist of eccentrically and sometimes deeply nested funnels and that the tubes lack transverse cross-walls, inconsistent with the traditional cone-in-cone morphological reconstruction. Tube walls are composed of micrometer-sized, more or less equant crystals. A number of Cloudina tubes branch dichotomously, in which daughter funnels split within parent ones. The Cloudina animal is interpreted to have been able to initiate biomineralization of new funnels within old ones. Its skeleton was probably secreted as calcite crystals suspended in organic matrix; the crystals do not appear to have nucleated and grown on a sheeted substrate. It was clearly capable of asexual reproduction, through budding within parent funnels rather than at the apertural end. The morphology, skeletogenesis, and asexual reproduction of Cloudina are broadly similar to modern serpulid annelids, indicating possible phylogenetic relationships or morphological convergence.
Article
Full-text available
Biostratigraphic, carbon isotope, and U-Pb zircon geochronological data from the Ara Group of Oman indicate an abrupt last appearance of Cloudina and Namacalathus coincident with a large-magnitude, but short-lived negative excursion in the carbon isotope composition of seawater that is globally coincident with the Precambrian-Cambrian boundary. U-Pb zircon age data from an intercalated ash bed directly define this negative excursion to be at 542.0 ± 0.3 Ma, consistent with previous age constraints from Siberia and Namibia. Combined with the global biostratigraphic record, these new data strengthen hypotheses invoking mass extinction within terminal Proterozoic ecosystems at or near the Precambrian-Cambrian boundary.
Article
Full-text available
Cloudina, an important Ediacaran index fossil, is considered as one of the earliest biomineralizing organisms. Its biological affinities have not been fully resolved and phylogenetic links with both annelids and cnidarians have traditionally been suggested. Differences in tube morphology, ultra structure and biomineralization suggest that Cloudina is not closely related to any recent skeletal annelid (e.g., serpulids, sabellids and cirratulids) and their skeletons are not homologous. The way of asexual reproduction in Cloudina resembles more that of cnidarians. The presence of a closed tube origin (base) in Cloudina is also compatible with the hypothesis of an animal of cnidarian grade.
Article
The Ediacaran skeletal tubular putative metazoan Cloudina occurs globally in carbonate settings, which both provided lithified substrates and minimized the cost of skeletonization. Habitat and substrate preferences and the relationship of Cloudina to other metazoans have not been fully documented, so we know little as to its ecological demands or community dynamics. In situ Cloudina from the Nama Group, Namibia (ca. 550-541 Ma), formed mutually attached reefs composed of successive assemblages in shallow, high-energy environments, and also communities attached to either stromatolites in storm-influenced deep inner-ramp settings or thin microbial mats in lower-energy habitats. Each assemblage shows statistically distinct tube diameter cohorts, but in sum, Cloudina shows an exponential frequency distribution of diameter size. In reefs, we document a periodicity of size variation, where mean, minimum, and maximum tube diameters vary together and show a systematic increase toward the top of each assemblage. We conclude that most Nama Group Cloudina represent one ecologically generalist taxon with highly variable size, that size was environmentally mediated, and that Cloudina could respond rapidly to periodic environmental changes. While Nama Group skeletal metazoans coexisted with soft-bodied biota, there was no apparent ecological interaction, as they were segregated into lithified carbonate and non-lithified clastic microbial mat communities, respectively. We infer that ecological flexibility allowed Cloudina to form varied communities that colonized diverse carbonate substrates under low levels of interspecific substrate competition. This is in notable contrast to the earliest Cambrian skeletal epibenthos that formed biodiverse reef communities with specialist niche occupancy.
Article
Sinotubulites is a late Ediacaran biomineralizing tubular fossil with a probable animal affinity. It is characterized by millimeter- to centimeter-sized and multi-layered tubes open at both ends. The tube consists of two morphologically different walls: a multi-layered inner wall with weak ornamentations and a multi-layered outer wall with transverse or oblique corrugations and sometimes longitudinal ridges. The majority of previously published Sinotubulites species are considered as synonymous with the type species: S. baimatuoensis. Three new species—S. triangularis n. sp., S. pentacarinalis n. sp., and S. hexagonus n. sp.—are reported from the late Ediacaran Beiwan Member of the Dengying Formation in southern Shaanxi Province, South China. The three new species are similar to the type species in having nested, multilayered inner and outer tube walls. However, they are different in their polygonal cross sections and longitudinal ridges. S. baimatuoensis is more or less circular in cross section and lack longitudinal ridges on the outer tube wall, whereas S. triangularis, S. pentacarinalis, and S. hexagonus are respectively triangular, pentagonal, and hexagonal in cross section with three, five, and six longitudinal ridges on the exterior surface of the outer wall. The new material adds to the diversity of late Ediacaran biomineralizing animals. The triradial, pentaradial, and hexaradial tubes of S. triangularis, S. pentacarinalis, and S. hexagonus share some intriguing similarities in body symmetry with some early Cambrian tubular fossils, although these Cambrian tubes are not open at both ends. Still, it would be interesting to explore the tantalizing possibility of evolutionary continuity of triradial, pentaradial, and hexaradial tubular animals across the Precambrian–Cambrian boundary.
Article
Reef-building in metazoans represents an important ecological innovation whereby individuals collectively enhance feeding efficiency and gain protection from competitors and predation. The appearance of metazoan reefs in the fossil record therefore indicates an adaptive response to complex ecological pressures. In the Nama Group, Namibia, we found evidence of reef-building by the earliest known skeletal metazoan, the globally distributed Cloudina, ~548 million years ago. These Cloudina reefs formed open frameworks without a microbial component but with mutual attachment and cementation between individuals. Orientated growth implies a passive suspension-feeding habit into nutrient-rich currents. The characteristics of Cloudina support the view that metazoan reef-building was promoted by the rise of substrate competitors and predators.
Article
Highlights ► Close association of Cloudina and microbial mats found in Ediacaran carbonate. ► A variety of three-dimensionally phosphatized Cloudina tube morphologies. ► Reconstruction of tube growth patterns of Cloudina. ► Paleoecological reconstruction of the epibenthic life mode of Cloudina.
Article
The uppermost part of the Miette Group (Windermere Supergroup) in eastern British Columbia has yielded shelly macrofossils in cliff-forming biostromal carbonates (Byng Formation). The biostromes are made up of two principal elements: intergrowths of complex sinuous, plate-like stromatolites (cf. Platella), and intervening planar to curviplanar pockets filled with packstone and wackestone crowded with Namacalathus and Cloudina, presumed calcified metazoans of uncertain biological affinities. Preservation is best in limestone, and the shells are mostly obliterated where the carbonate is dolomitized. This assemblage was previously known only from the Nama sequence in Namibia. The new find in the antipodal Miette Group in the Canadian Rocky Mountains greatly extends its geographic range, and suggests a more widespread distribution in similar facies in intermediate areas. Both assemblages constitute the earliest occurrences of shelly fossils in their respective regions.
Article
Predation as an important driver of evolutionary change long has been assumed, despite difficulties to substantiate it with specific examples of predatory interaction, especially for the early Paleozoic diversification of animal life. This study corroborates the existence of shell-drilling predation in the uppermost Neoproterozoic of China. Nearly one-fifth of almost one hundred tubular shells of one of the earliest mineralized animals, Cloudina, are perforated by undoubted predatory borings 15-85 μm wide. By contrast, no specimens of co-occurring shells belonging to Sinotubulites were affected. The identity of the predator remains elusive, but variation in size of the borings suggests a predatory lifestyle throughout its growth, after it reached a minimum size. The relatively uniform distance of the borings from the shell apertures points to either control by the life orientation of the shells, such as the position of the sediment surface, or, more likely, an avoidance response by the predator to protective measures located near the aperture. Assuming Sinotubulites had similar life habits and was potential prey, the absence of borings in this taxon is evidence that these tubes may have been protected by organic material or toxins that fended off shell-drilling predators. Hence, this earliest example of predation in the fossil record already shows prey selectivity and site-specific behavior, pointing to a level of Precambrian predator-prey interaction that approaches the complexity seen in younger Paleozoic benthic animal communities. This is consistent with the suggestion that predation was indeed an active contributor to the Cambrian radiations.
Article
The earliest 'shdly' fossils deserve more detailed studies than they have received. Examination of the Cambrian genus Volborthella shows that it resembles in significant characters tubes of sabellariid worms, and on this basis the morphology and ecology of the animal can be reconstructed. The Cribricyathida, which include Cloudina and range from late Precambrian to lower Cambrian, are not related to Archaeoeyatha but are polychaete worm tubes with some structural characters which resemble those of serpulids. The problematic Angustiochreida (Anabarites etc.), of similar age, also show such resemblances. The first appearance in the geological record of mineralized skeletons ('shelly fossils'), built according to various interrelated modes in annelids and in a different manner in other Metazoa, is not a suitable stratigraphic marker. The early differentiation of annelid worms can now be documented palaeontologically.
Article
The terminal Ediacaran genus Cloudina includes some of the earliest biomineralized fossils. It consists of a tube formed by stacked funnel-shaped elements, and is usually interpreted as the external skeleton of an early metazoan. Although a number of species have been described within this genus, their distinctiveness remains unclear and they may all belong to the type species, Cloudina hartmannae Germs, 1972. Here we describe the new species Cloudina carinata, from central Spain. C. carinata n. sp. has a distinct morphology characterized by external longitudinal crests, which confer on the tube an irregular polygonal cross-section. The funnels have a thickened apertural rim and a basal, slightly constricted circular opening. Successive funnels appear less deeply imbricated than in previously described material of Cloudina. The evidence of tube disarticulation in the material studied, particularly the abundance of loose funnels, indicates that funnels were secreted as independent elements, not fused to the previous ones. However, they could become fused during the life of the organism through the precipitation of inorganic cements between their walls. Several specimens of C. carinata n. sp. show evidence of asexual reproduction.
Article
The terminal Neoproterozoic (Ediacaran) Dengying Formation in southern Shaanxi, China, hosts two types of conical fossils: one is the so-called Conotubus, found in siliciclastic rocks in the lower and middle part of the Gaojiashan Member; the other is the renowned Cloudina in carbonate rocks of the upper Gaojiashan Member and succeeding Beiwan Member. Conotubus are conical and gently curved tubular fossils, with a variable rate of expansion. They are built of multiple thin, steep, eccentrically nested funnels set one within the next. A detailed comparison of the two conical fossils suggests that the organic tubes of Conotubus may be the precursor of the mineralized Cloudina tubes; this inference is consistent with their similarities in both wall structure and life style. Our research thus suggests that the organic skeleton preceded the rise of the mineralized skeleton in Cloudina-like fossils. Sophisticated hypotheses have been advocated, some linking the skeletal genesis to increasing levels of Ca2+ in the seas, others to the enlargement of body sizes of animals. Yet our findings have supported the ‘arms race’ hypothesis: skeletons evolved primarily through selective predation pressure. Copyright © 2007 John Wiley & Sons, Ltd.
Article
The Corumbá Group, cropping out in the southern Paraguay Belt in Brazil, is one of the most complete Ediacaran sedimentary archives of palaeogeographic, climatic, biogeochemical and biotic evolution in southwestern Gondwana. The unit hosts a rich fossil record, including acritarchs, vendotaenids (Vendotaenia, Eoholynia), soft-bodied metazoans (Corumbella) and skeletal fossils (Cloudina, Titanotheca). The Tamengo Formation, made up mainly of limestones and marls, provides a rich bio- and chemostratigraphic record. Several outcrops, formerly assigned to the Cuiabá Group, are here included in the Tamengo Formation on the basis of lithological and chemostratigraphical criteria. High-resolution carbon isotopic analyses are reported for the Tamengo Formation, showing (from base to top): (1) a positive δ13C excursion to +4‰ PDB above post-glacial negative values, (2) a negative excursion to −3.5‰ associated with a marked regression and subsequent transgression, (3) a positive excursion to +5.5‰, and (4) a plateau characterized by δ13C around +3‰. A U-Pb SHRIMP zircon age of an ash bed interbedded in the upper part of the δ13C positive plateau yielded 543 ± 3 Ma, which is considered as the depositional age (Babinski et al., 2008a). The positive plateau in the upper Tamengo Formation and the preceding positive excursion are ubiquitous features in several successions worldwide, including the Nama Group (Namibia), the Dengying Formation (South China) and the Nafun and Ara groups (Oman). This plateau is constrained between 542 and 551 Ma, thus consistent with the age of the upper Tamengo Formation. The negative excursion of the lower Tamengo Formation may be correlated to the Shuram–Wonoka negative anomaly, although δ13C values do not fall beyond −3.5‰ in the Brazilian sections. Sedimentary breccias occur just beneath this negative excursion in the lower Tamengo Formation. One possible interpretation of the origin of these breccias is a glacioeustatic sea-level fall, but a tectonic interpretation cannot be completely ruled out.
Article
  The Cambrian index fossil Treptichnus pedum is reported from the Puerto Blanco Formation near Pitiquito, Sonora, Mexico, and new occurrences of the Neoproterozoic index fossil Cloudina are reported from the underlying La Ciénega Formation. Considered together, these fossils constrain the location of the Ediacaran/Cambrian boundary in Mexico. The suite of fossils in this sequence is important because it provides an independent biostratigraphic datum for constraining the position of Laurentia during the onset of metazoan diversification, for testing proposed lithostratigraphic correlations among western North American Neoproterozoic–Cambrian successions, and for testing regional tectonic paradigms such as the Mojave-Sonora Megashear hypothesis.
Article
The Corumbá Group of SW Brazil and the Arroyo del Soldado Group (ASG) of Uruguay are correlated on the basis of litho-, bio- and chemostratigraphy. Both units represent marine sedimentation with alternating siliciclastics and carbonates developed on a stable continental shelf. In the Corumbá basin, sedimentation began in the Varangerian, represented by the glaciomarine Puga Formation. A series of sea-level fluctuations coupled with climatic changes are recorded up section. While uppermost deposits of the ASG are of lowermost Cambrian age, sedimentation ceased in the latest Vendian in the Corumbá basin. An assemblage of six species of organic-walled microfossils dominated by Bavlinella faveolata and Soldadophycus bossii, three species of vendotaenids and two species of skeletal fossils (Cloudina and Titanotheca) is described from the Corumbá Group. The vendotaenid Eoholynia corumbensis sp. nov is described from siltstones of the Guaicurus Formation. An important diversity of skeletal fossils in the Corumbá, Arroyo del Soldado and Nama groups points to favourable Vendian palaeoclimatic conditions in SW-Gondwana. Preliminary carbon isotopic data show a series of alternating positive and negative excursions, corroborating the upper Vendian age indicated by fossils for both units. Previously reported strontium isotopic data are also consistent with this age. It is postulated that the Corumbá and ASGs were deposited onto the same shelf, which opened to the east. The Rio de la Plata Superterrane (Craton) extends farther to the north than previously expected, or it was already amalgamated with the Amazonian Craton by Vendian times. Collision of the platform with the Paraná Block caused closure of the basin during the Cambrian-Early Ordovician. Finally, models of Neoproterozoic glaciations based on enhanced bioproductivity driven by high nutrient availability are discussed.
Article
Cloudina-bearing biosparites and biomicrites in the lower part of the Nama Group, Namibia, contain a wide morphological diversity of shell fragments that can all be attributed to the two named species C. hartmannae and C. riemkeae. The unusual shell structure of Cloudina gives rise to a characteristic suite of taphonomic and diagenetic features that can be used to identify Cloudina-bearing deposits within the Nama Group and in other terminal Proterozoic deposits around the world. It is possible, moreover, to suggest that metazoan biomineralization occurred on a global scale by the latest Proterozoic, at the same time that evidence for complex multicellularity and locomotion in animals appears in siliciclastic "Ediacaran' rocks in the form of body and trace fossils. -from Author
Cloudina hartmannae Germs, 1972 in Glaessner, Pl. 1: Fig. 2, p. 266; Fig. 3, p. 267; Pl. 2: Figs. 1-6, p. 267 Cloudina hartmanae Germs, 1972 in Grant, Fig. 4: E-F, p. 270; Fig. 6: A-B, p. 272; Fig. 8: D, p. 285. 1990 Cloudina sp. (Germs, 1972) Grant, Fig. 10: E, p. 280
  • Aulophycus Lucianoi Beurlen
  • Sommer Pl
  • Hua
Aulophycus lucianoi Beurlen and Sommer, 1957 Pl. I-VI, p. 36-47. 1972 Cloudina hartmannae Germs, 1972 Pl. 1: Figs. 1-7, pp. 756-757; Fig. 3: C, p. 758. 1976 Cloudina hartmannae Germs, 1972 in Glaessner, Pl. 1: Fig. 2, p. 266; Fig. 3, p. 267; Pl. 2: Figs. 1-6, p. 267. 1987 Cloudina lucianoi (Beurlen and Sommer, 1957) in Zaine and Fairchild, Est. 1: Figs. 1-7, pp. 806-807. 1990 Cloudina hartmanae Germs, 1972 in Grant, Fig. 4: E-F, p. 270; Fig. 6: A-B, p. 272; Fig. 8: D, p. 285. 1990 Cloudina sp. (Germs, 1972) Grant, Fig. 10: E, p. 280. 2000 Cloudina lucianoi (Beurlen and Sommer, 1957) in Gaucher pl.: 21.1, not 2 and 3. 2003 Cloudina hartmannae Germs, 1972 in Hua et al., Figs. D-H, p. 456. 2003 Cloudina lucianoi (Beurlen and Sommer, 1957) in Gaucher et al., Fig. 10: A-B, D-K; not Fig.10C, p. 262. 2005 Cloudina hartmannae Germs, 1972 in Hua et al., Figs. A-P, p. 278. ? 2007 Cloudina hartmannae Germs, 1972 in Hua et al., Fig. 5: 4 and 6, p. 269. 2011 Cloudina lucianoi (Beurlen and Sommer, 1957) in Warren et al., Fig. 14. Biostratigraphic proposal with stratigraphic distribution of Cloudina lucianoi (Beurlen and Sommer, 1957) and Corumbella werneri Hahn et al., 1982 within the studied outcrops of Corumbá and Ladário municipalities, Mato Grosso do Sul State, Brazil and correlation with section 1 and section 2 of the eastern portion of the Itapucumi Group (the coordinates of these locations are 22°46.18′S, 57°29.10′W and 22°42.57′S/5730.35′W, respectively) presented in Warren et al. (2011).
  • R R Adorno
R.R. Adorno et al. Precambrian Research 301 (2017) 19-35
Three-dimensional Cloudina specimens extraction from limestone of the Nama Group, Namibia
  • R R References Adôrno
  • D A Do Carmo
  • M Denezine
  • C G Rodriguez
References Adôrno, R.R., Do Carmo, D.A., Denezine, M., Rodriguez, C.G., 2016. Three-dimensional Cloudina specimens extraction from limestone of the Nama Group, Namibia. In: 35th International Geological Congress, Cape Town, South Africa,. Available in: < https://www.americangeosciences.org/information/igc >.
U-Pb SHRIMP geochronology and isotope chemostratigraphy (C, O, Sr) of the Tamengo Formation, southern Paraguay Belt, Brazil
  • M Babinski
  • P C Boggiani
  • C M Fanning
  • T R Fairchild
  • C M Simon
  • A N Sial
Babinski, M., Boggiani, P.C., Fanning, C.M., Fairchild, T.R., Simon, C.M., Sial, A.N., 2008. U-Pb SHRIMP geochronology and isotope chemostratigraphy (C, O, Sr) of the Tamengo Formation, southern Paraguay Belt, Brazil. In: VI South American Symposium on Isotiope Geology, p. 160.
Life history and autecology of an Ediacaran index fossil: Development and dispersal of Cloudina
  • I Cortijo
  • Y Cai
  • H Hua
  • J D Schiffbauer
  • S Xiao
Cortijo, I., Cai, Y., Hua, H., Schiffbauer, J.D., Xiao, S., 2015. Life history and autecology of an Ediacaran index fossil: Development and dispersal of Cloudina. Gondwana Res. 28, 419-424. http://dx.doi.org/10.1016/j.gr.2014.05.0010.
Approach on taxonomy and paleozoogeographic distribution of Cloudina Germs In: Corumbá Meeting 2013-The Neoproterozoic Paraguay Belt (Brazil): Glaciation, Iron-Manganese Formation and Biota
  • Do Carmo
  • D A Vasconcelos
  • J Tobias
  • T C Walde
  • D H G Denezine
  • M Paiva
Do Carmo, D.A., Vasconcelos, J., Tobias, T.C., Walde, D.H.G., Denezine, M., Paiva, R.G., 2013a. Approach on taxonomy and paleozoogeographic distribution of Cloudina Germs, 1972. In: Corumbá Meeting 2013-The Neoproterozoic Paraguay Belt (Brazil): Glaciation, Iron-Manganese Formation and Biota, Corumbá, p. 37.
Taxonomia e distribuição paleozoogeográfica da Cloudina Germs
  • Do Carmo
  • D A Vasconcelos
  • J Tobias
  • T C Walde
  • D H G Denezine
  • M Paiva
Do Carmo, D.A., Vasconcelos, J., Tobias, T.C., Walde, D.H.G., Denezine, M., Paiva, R.G., 2013b. Taxonomia e distribuição paleozoogeográfica da Cloudina Germs, 1972 no Ediacariano do Gondwana. In: XXIII Congresso Brasileiro de Paleontologia, Gramado, p. 116.
Evidências paleontológicas de uma possível idade-Ediacariana‖ ou Cambriana Inferior, para a parte leste do Grupo Corumbá
  • T R Fairchild
Fairchild, T.R., 1978. Evidências paleontológicas de uma possível idade-Ediacariana‖ ou Cambriana Inferior, para a parte leste do Grupo Corumbá (Mato Grosso do Sul). In: CONGRESSO BRASILEIRO DE GEOLOGIA, 30, Recife, 1978. Resumos das Comunicações, pp. 181.
  • G Hahn
  • R Hahn
  • O H Leonardos
  • H D Pflug
  • D H G Walde
Hahn, G., Hahn, R., Leonardos, O.H., Pflug, H.D., Walde, D.H.G., 1982. Korperlich erhaltene Scyphozoen-Reste aus dem Jungprakambrium Brasiliens. Geol. Palaeontol. 16, 1-18.
Ediacaran and Cambrian index fossils from Sonara
  • F Sour-Tovar
  • J W Hagadorn
  • S Huitro
Sour-tovar, F., Hagadorn, J.W., Huitro, S., 2007. Ediacaran and Cambrian index fossils from Sonara, Mexico. Palaeontology 50, 169-175.
The study of the late Sinian -early Cambrian biotas from the northern margin of Yangtze Platform
  • L Zhang
  • Y Li
  • J Dong
Zhang, L., Li, Y., Dong, J., 1992. The study of the late Sinian -early Cambrian biotas from the northern margin of Yangtze Platform. Sci. Tech. Doc. Publ. House 1-135.
Germs, 1972) Grant, Fig. 10: E, p
  • Cloudina Sp
Cloudina sp. (Germs, 1972) Grant, Fig. 10: E, p. 280.