Q2. What are the future works in this paper?
The latter presenting the intriguing possibility that the diversification of marine ecosystems was on a single trajectory that peaked in the Devonian.
The Furongian (late Cambrian) Biodiversity Gap: Real or apparent?
TL;DR: The Furongian gap as mentioned in this paper is defined as the gap between the Cambrian Explosion and the Great Ordovician Biodiversification Event, exemplified by a marked drop in biodiversity.
About: This article is published in Palaeoworld.The article was published on 2019-03-01 and is currently open access. It has received 35 citations till now. The article focuses on the topics: Ordovician & Paleozoic.
Summary (2 min read)
2. Background
- Palaeontologists have long accepted that the fossil record is incomplete but nevertheless adequate to describe and understand the history of life on their planet.
- Some hundred years after publication of the 1st edition of Darwin’s influential work, interest intensified on the adequacy and quality of the fossil record as more complex and sophisticated analyses of the evolution of fossil organisms and their diversity were developed through deep time.
- Raup, in a succession of key papers, developed the concept of time-dependent and timeindependent biases (Raup, 1972, 1976a, 1976b).
- These key factors may provide some explanation for the current dearth of data from this critical interval.
4. Fact or artefact?
- Furongian rocks are known from all major Cambrian palaeocontinents and widely distributed in many regions, such as in Laurentia, South China, Siberia and Baltica.
- This is true for a number of classic areas of Cambrian research from western Gondwana, for example the Barrandian area of Bohemia, Spain and Morocco, together with parts of the Baltic (e.g., Estonia) where the Furongian is poorly represented or consists of shallow-water deposits that are poorly fossiliferous.
- In fact, total and SIB diversity follow comparable trajectories, which seems to fit to occurrence signal, while BC diversity reflects an independent pattern (Fig. 1).
- To avoid inconsistences generated by false positives, the authors ran a two-time data analysis from raw and generalized-differenced data for comparisons (see http://www.graemetlloyd.com/methgd.html for implementation).
- Evidence seems to suggest that, the overall observed diversity (in particular total diversity) may be driven by sampling, sampling does not account for the entire diversity signal; a biological signal is still legible in the fossil record.
5. Natural causes
- Diversity curves based on the Sepkoski Database indicate a high frequency of extinctions during the late Cambrian (Fig. 3).
- The frequency and magnitude of these events, especially when displayed as proportions of extinct genera, are impressive (see e.g., Melott and Bambach, 2012; Erlykin et al., 2018).
- Two globally significant carbon isotope excursions are recognized in the Furongian, the Steptoean Positive carbon Isotope Excursion in the Paibian Stage and the HEllnmaria — Red Tops Boundary Event (HERB) or Top of Cambrian Excursion (TOCE) in provisional Stage 10 (Zhu et al., 2006; Fig. 3 herein).
- The magnitude of the SPICE and the HERB Event in shale successions is, however, subdued compared to the δ13Ccarb excursions recorded in carbonate successions, and the δ13Corg signal is commonly half, or less than half, of the magnitude the δ13Ccarb signal (see Ahlberg et al., in press and references therein).
- The interpretation of the SPICE as a global anoxic event has, however, been questioned, because the presence of benthic faunal elements and bioturbation in almost all SPICE-related sections excludes widespread and persistent anoxia or euxinia, but rather suggest oxic or dysoxic sea floor conditions during most of the SPICE interval (Egenhoff et al., 2015; Wotte and Strauss, 2015).
6. Conclusions
- Currently there is marked interregnum in biodiversity between the high-profile, exceptionally-preserved biotas of the Cambrian Explosion, preserved across a number of Lagerstätten, and the four-fold increase in numbers of families, genera and species during the Great Ordovician Biodiversification Event.
- There are relatively few fossil collections, compared with older and younger strata, through this interval coupled with a lack of taxonomic work on its biotas.
- Extreme fluctuations are present in Furongian environments, providing a barrier to the expansion of the marine ecosystem and its biodiversity.
- That had to wait until the Early Ordovician.
Did you find this useful? Give us your feedback
Citations
More filters
TL;DR: A review of biodiversity curves of marine organisms indicates that, despite fluctuations in amplitude (some large), a large-scale, long-term radiation of life took place during the early Palaeozoic Era; it was aggregated by a succession of more discrete and regionalized radiations across geographies and within phylogenies.
Abstract: A review of biodiversity curves of marine organisms indicates that, despite fluctuations in amplitude (some large), a large-scale, long-term radiation of life took place during the early Palaeozoic Era; it was aggregated by a succession of more discrete and regionalized radiations across geographies and within phylogenies. This major biodiversification within the marine biosphere started during late Precambrian time and was only finally interrupted in the Devonian Period. It includes both the Cambrian Explosion and the Great Ordovician Biodiversification Event. The establishment of modern marine ecosystems took place during a continuous chronology of the successive establishment of organisms and their ecological communities, developed during the ‘Cambrian substrate revolution’, the ‘Ordovician plankton revolution’, the ‘Ordovician substrate revolution’, the ‘Ordovician bioerosion revolution’ and the ‘Devonian nekton revolution’. At smaller scales, different regional but important radiations can be recognized geographically and some of them have been identified and named (e.g. those associated with the ‘Richmondian Invasion’ during Late Ordovician time in Laurentia and the contemporaneous ‘Boda event’ in parts of Europe and North Africa), in particular from areas that were in or moved towards lower latitudes, allowing high levels of speciation on epicontintental seas during these intervals. The datasets remain incomplete for many other geographical areas, but also for particular time intervals (e.g. during the late Cambrian ‘Furongian Gap’). The early Palaeozoic biodiversification therefore appears to be a long-term process, modulated by bursts in significant diversity and intervals of inadequate data, where its progressive character will become increasingly clearer with the availability of more complete datasets, with better global coverage and more advanced analytical techniques.
46 citations
Cites background from "The Furongian (late Cambrian) Biodi..."
...The Furongian Biodiversity Gap has been recently noted in a number of papers (e.g. Servais & Harper, 2018) and examined in detail (Harper et al. 2019b)....
[...]
...Some of the subsequent benchmark studies during the twentieth and twenty-first centuries have been recently charted by Harper et al. (2019b) in connection with unravelling the Furongian Biodiversity Gap; the studies of Newell (1959), Raup (1972) and Valentine (1973) have been particularly…...
[...]
...Harper et al. (2019b) have discussed this gap in detail, concluding that diversity has been significantly underestimated by a paucity of examined rock, compounded by a distinctive palaeogeography, extreme climates and fluctuating environments....
[...]
...…with exceptional preservation, such as the Burgess Shale in the Canadian Rocky Mountains (e.g. Briggs et al. 1994; Erwin & Valentine, 2013; Briggs, 2015), Chengjiang in South China (e.g. Hou et al. 2017; Yang et al. 2018), Sirius Passet in North Greenland (e.g. Harper et al. 2019a) and others....
[...]
TL;DR: In this paper, molecular clock data suggest with high probability a Cambrian origin of Embryophyta (also called land plants), indicating that their terrestrialization most probably started about 500 Ma.
44 citations
01 Jan 2016
TL;DR: The principles of paleontology is available in our book collection and an online access to it is set as public so you can get it instantly as discussed by the authors, which is the only way to download any of our books like this one.
Abstract: Thank you for reading principles of paleontology. Maybe you have knowledge that, people have look numerous times for their chosen books like this principles of paleontology, but end up in harmful downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they juggled with some malicious virus inside their desktop computer. principles of paleontology is available in our book collection an online access to it is set as public so you can get it instantly. Our digital library spans in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the principles of paleontology is universally compatible with any devices to read.
42 citations
TL;DR: In this paper, a critical analysis of published biodiversity curves and of their own data confirm the traditional view; the Ordovician radiation is a complex, long-term process of multiple biodiversifications of marine organisms.
Abstract: The Ordovician biodiversification is considered one of the most significant radiations in the marine ecosystems of the entire Phanerozoic. Originally recognized as the ‘Ordovician Radiation’, a label retained during most of the 1980s and 1990s, the term ‘Great Ordovician Biodiversification Event’ (GOBE) was coined in the late 1990s and was subsequently adopted by most of the scientific community. The Ordovician biodiversification, has always been considered as a long-term adaptive radiation, resulting in the sum of the different individual diversifications of all groups of marine organisms that occurred diachronously during the entire Ordovician. More recently, based on different palaeontological datasets, comprising data from different palaeogeographical areas, the Ordovician radiation has been interpreted to occur at different times in different places. This is most probably related to the palaeogeography of the Ordovician, when the major palaeocontinents were variously located in low latitudes to develop biodiversity ‘hotspots’ during different time intervals. In particular, some authors, using the potentially biased dataset of the Paleobiology Database (PBDB), have considered the GOBE to be an early Middle Ordovician global bio-event. Accordingly, the GOBE thus apparently corresponds to a relatively short time interval, with dramatic diversity fluctuations resulting in a profound change in marine environments at a global scale, visible by a major pulse in biodiversification of all fossil groups around the world. A critical analysis of the published biodiversity curves and of our own data confirm the traditional view; the Ordovician radiation is a complex, long-term process of multiple biodiversifications of marine organisms. Rapid increases in diversity can be identified for some fossil groups, at regional or palaeocontinental levels, in particular within limited datasets. However, a short, dramatic event that triggered major biodiversity pulses of all fossil groups at a global level at a particular time interval is an oversimplification.
39 citations
TL;DR: The Steptoean Positive Isotopic Carbon Excursion (SPICE) is a prominent chemostratigraphic feature in the Lower Paleozoic. as discussed by the authors quantitatively evaluate the variability in SPICE records, and document that while the excursion is a global signature, its stratigraphic expression is influenced by such conditions as paleolatitude, paleocontinent, water depth, and facies.
21 citations
References
More filters
TL;DR: This work compares the rates of expansion and truncation of preserved marine sedimentary basins to rates of origination and extinction among Phanerozoic marine animal genera and suggests that the processes responsible for producing variability in the sedimentary rock record, such as plate tectonics and sea-level change, may have been dominant and consistent macroevolutionary forces throughout the Phanrozoic.
Abstract: The causes of mass extinctions and the nature of taxonomic radiations are central questions in paleobiology. Several episodes of taxonomic turnover in the fossil record, particularly the major mass extinctions, are generally thought to transcend known biases in the geologic record and are widely interpreted as distinct macroevolutionary phenomena that require unique forcing mechanisms. Here, by using a previously undescribed compilation of the durations of sedimentary rock sequences, I compare the rates of expansion and truncation of preserved marine sedimentary basins to rates of origination and extinction among Phanerozoic marine animal genera. Many features of the highly variable record of taxonomic first and last occurrences in the marine animal fossil record, including the major mass extinctions, the frequency distribution of genus longevities, and short- and long-term patterns of genus diversity, can be predicted on the basis of the temporal continuity and quantity of preserved sedimentary rock. Although these results suggest that geologically mediated sampling biases have distorted macroevolutionary patterns in the fossil record, preservation biases alone cannot easily explain the extent to which the sedimentary record duplicates paleobiological patterns. Instead, these results suggest that the processes responsible for producing variability in the sedimentary rock record, such as plate tectonics and sea-level change, may have been dominant and consistent macroevolutionary forces throughout the Phanerozoic.
260 citations
"The Furongian (late Cambrian) Biodi..." refers background in this paper
...Peters’ (2005) common cause hypothesis posited that during intervals of high sea level biodiversity is actually high and during regression it drops (see also Hannisdal and Peters, 2012)....
[...]
TL;DR: The Steptoean positive carbon isotope excursion (SPICE) as discussed by the authors is a global oceanographic event that confirms intercontinental correlations between different biogeographic realms based on agnostids and other blue-water trilobites.
239 citations
TL;DR: In this paper, a model involving the cascading development of γ (interprovincial), β (intercommunity) and α (intra-community) diversity highlights the interplay between ecology, environment, geography and adaptive strategy during the event.
232 citations
"The Furongian (late Cambrian) Biodi..." refers background or methods in this paper
...Event (GOBE) is underpinned by a massive increase in diversity at the lower taxonomic levels (Harper, 2006; Rong et al., 2007; Harper and Servais, 2018), commonly apparent across clastic and limestone facies initially on shallow shelves....
[...]
...…Ordovician Biodiversification AC CE PT ED M AN US CR IP T Event (GOBE) is underpinned by a massive increase in diversity at the lower taxonomic levels (Harper, 2006; Rong et al., 2007; Harper and Servais, 2018), commonly apparent across clastic and limestone facies initially on shallow shelves....
[...]
...The parametric Pearson (r), and non-parametric Spearman (rs) and Kendall (t) correlation tests were used (see Hammer and Harper, 2006)....
[...]
TL;DR: It is shown that new assessment methods, in which the order of fossils in the rocks (stratigraphy) is compared with the order inherent in evolutionary trees (phylogeny), provide a more convincing analytical tool: stratigraphy and phylogeny offer independent data on history.
Abstract: Does the fossil record present a true picture of the history of life1,2,3, or should it be viewed with caution4,5,6? Raup5 argued that plots of the diversification of life2 were an illustration of bias: the older the rocks, the less we know. The debate was partially resolved by the observation7 that different data sets gave similar patterns of rising diversity through time. Here we show that new assessment methods, in which the order of fossils in the rocks (stratigraphy) is compared with the order inherent in evolutionary trees (phylogeny), provide a more convincing analytical tool: stratigraphy and phylogeny offer independent data on history. Assessments of congruence between stratigraphy and phylogeny for a sample of 1,000 published phylogenies show no evidence of diminution of quality backwards in time. Ancient rocks clearly preserve less information, on average, than more recent rocks. However, if scaled to the stratigraphic level of the stage and the taxonomic level of the family, the past 540 million years of the fossil record provide uniformly good documentation of the life of the past.
191 citations
TL;DR: A new compilation of the amount of exposed marine sedimentary rock is used to predict how the observed fossil record of extinction would appear if the time series of true extinction rates were in fact smooth, and supports the hypothesis that much of the observed short-term volatility in extinction rates is an artefact of variability in the stratigraphic record.
Abstract: The causes of mass extinctions and the nature of biological selectivity at extinction events are central questions in palaeobiology. It has long been recognized, however, that the amount of sedimentary rock available for sampling may bias perceptions of biodiversity and estimates of taxonomic rates of evolution. This problem has been particularly noted with respect to the principal mass extinctions. Here we use a new compilation of the amount of exposed marine sedimentary rock to predict how the observed fossil record of extinction would appear if the time series of true extinction rates were in fact smooth. Many features of the highly variable record of apparent extinction rates within marine animals can be predicted on the basis of temporal variation in the amount of exposed rock. Although this result is consistent with the possibility that a common geological cause determines both true extinction rates and the amount of exposed rock, it also supports the hypothesis that much of the observed short-term volatility in extinction rates is an artefact of variability in the stratigraphic record.
181 citations
"The Furongian (late Cambrian) Biodi..." refers background in this paper
...Whereas Peters and Foote (2002) emphasised a correlation between named formations and named fossils; rather the appearance and disappearance of fossils may be linked to the presence and absence of strata....
[...]