Fossil Record Quality Research Articles

Biogeographic history of Palearctic caudates revealed by a critical appraisal of their fossil record quality and spatio-temporal distribution.

The disjunct geographical range of many lineages of caudates points to a complex evolutionary and biogeographic history that cannot be disentangled by only considering the present-day distribution of salamander biodiversity. Here, we provide a critical reappraisal of the published fossil record of caudates from the Palearctic and quantitatively evaluate the quality of the group's fossil record. Stem-Urodela and Karauridae were widespread in the Palearctic in the Middle Jurassic, suggesting an earlier, unsampled diversification for this group. Cryptobranchidae reached Europe no later than the Oligocene, but this clade was subsequently extirpated from this continent, as well as from western and central Asia. The relatively recent appearance of hynobiids in the fossil record (Early Miocene) is most likely an artefact of a taphonomic bias against the preservation of high-mountain, stream-type environments which early members likely inhabited. Salamandroids first appear in Europe, expanding into Asia by the Miocene. The apparently enigmatic and disjunct distribution of extant caudate lineages is therefore explained by a wider past geographical range, as testified by the fossil record, which was fragmented during the late Cenozoic by a combination of tectonic (i.e. the uplift of the Tibetan Plateau) and climatic drivers, resulting in regional extirpations.

Pennsylvanian sponge from the Mecca Quarry Shale, Carbondale Group (Indiana, USA) and the paleobiogeographic distribution ofTeganiellain the paleoequatorial region of Laurentia

AbstractThe sponges may be the oldest group of Metazoa, with a long and successful evolutionary history. Despite their intermittent fossil record quality, the group has been considered reliable for paleoecological and paleobiogeographic analyses because they have inhabited various types of aquatic environments, forming a significant part of benthic communities. We have presented a detailed description of a new species from the genusTeganiella,Teganiella finksinew species, which expands the chronologic range and classifies the genus as endemic to the paleoequatorial regions of Laurentia associated with arid climate conditions linked to hypersaline periods. Combining the paleoecological and paleoenvironmental features of theTeganiellaspecies, our findings also suggest a trend toward more closed-inlet conditions, which may be related to competition and/or specific habitat supplies, for example, heavy metals such as vanadium, zinc, and molybdenum.UUID:http://zoobank.org/12901a63-7cd5-4207-ac7a-0ce12649fcaf

Deep time diversity of metatherian mammals: implications for evolutionary history and fossil-record quality

AbstractDespite a global fossil record, Metatheria are now largely restricted to Australasia and South America. Most metatherian paleodiversity studies to date are limited to particular subclades, time intervals, and/or regions, and few consider uneven sampling. Here, we present a comprehensive new data set on metatherian fossil occurrences (Barremian to end Pliocene). These data are analyzed using standard rarefaction and shareholder quorum subsampling (including a new protocol for handling Lagerstätte-like localities).Global metatherian diversity was lowest during the Cretaceous, and increased sharply in the Paleocene, when the South American record begins. Global and South American diversity rose in the early Eocene then fell in the late Eocene, in contrast to the North American pattern. In the Oligocene, diversity declined in the Americas, but this was more than offset by Oligocene radiations in Australia. Diversity continued to decrease in Laurasia, with final representatives in North America (excluding the later entry ofDidelphis virginiana) and Europe in the early Miocene, and Asia in the middle Miocene. Global metatherian diversity appears to have peaked in the early Miocene, especially in Australia. Following a trough in the late Miocene, the Pliocene saw another increase in global diversity. By this time, metatherian biogeographic distribution had essentially contracted to that of today.Comparison of the raw and sampling-corrected diversity estimates, coupled with evaluation of “coverage” and number of prolific sites, demonstrates that the metatherian fossil record is spatially and temporally extremely patchy. Therefore, assessments of macroevolutionary patterns based on the raw fossil record (as in most previous studies) are inadvisable.

The phylogeny and evolutionary history of tyrannosauroid dinosaurs.

Tyrannosauroids—the group of carnivores including Tyrannosaurs rex—are some of the most familiar dinosaurs of all. A surge of recent discoveries has helped clarify some aspects of their evolution, but competing phylogenetic hypotheses raise questions about their relationships, biogeography, and fossil record quality. We present a new phylogenetic dataset, which merges published datasets and incorporates recently discovered taxa. We analyze it with parsimony and, for the first time for a tyrannosauroid dataset, Bayesian techniques. The parsimony and Bayesian results are highly congruent, and provide a framework for interpreting the biogeography and evolutionary history of tyrannosauroids. Our phylogenies illustrate that the body plan of the colossal species evolved piecemeal, imply no clear division between northern and southern species in western North America as had been argued, and suggest that T. rex may have been an Asian migrant to North America. Over-reliance on cranial shape characters may explain why published parsimony studies have diverged and filling three major gaps in the fossil record holds the most promise for future work.

Preservational bias controls the fossil record of pterosaurs.

Pterosaurs, a Mesozoic group of flying archosaurs, have become a focal point for debates pertaining to the impact of sampling biases on our reading of the fossil record, as well as the utility of sampling proxies in palaeodiversity reconstructions. The completeness of the pterosaur fossil specimens themselves potentially provides additional information that is not captured in existing sampling proxies, and might shed new light on the group's evolutionary history. Here we assess the quality of the pterosaur fossil record via a character completeness metric based on the number of phylogenetic characters that can be scored for all known skeletons of 172 valid species, with averaged completeness values calculated for each geological stage. The fossil record of pterosaurs is observed to be strongly influenced by the occurrence and distribution of Lagerstätten. Peaks in completeness correlate with Lagerstätten deposits, and a recovered correlation between completeness and observed diversity is rendered non-significant when Lagerstätten species are excluded. Intervals previously regarded as potential extinction events are shown to lack Lagerstätten and exhibit low completeness values: as such, the apparent low diversity in these intervals might be at least partly the result of poor fossil record quality. A positive correlation between temporal patterns in completeness of Cretaceous pterosaurs and birds further demonstrates the prominent role that Lagerstätten deposits have on the preservation of smaller bodied organisms, contrasting with a lack of correlation with the completeness of large-bodied sauropodomorphs. However, we unexpectedly find a strong correlation between sauropodomorph and pterosaur completeness within the Triassic-Jurassic, but not the Cretaceous, potentially relating to a shared shift in environmental preference and thus preservation style through time. This study highlights the importance of understanding the relationship between various taphonomic controls when correcting for sampling bias, and provides additional evidence for the prominent role of sampling on observed patterns in pterosaur macroevolution.

'Fish' (Actinopterygii and Elasmobranchii) diversification patterns through deep time.

Actinopterygii (ray-finned fishes) and Elasmobranchii (sharks, skates and rays) represent more than half of today's vertebrate taxic diversity (approximately 33000 species) and form the largest component of vertebrate diversity in extant aquatic ecosystems. Yet, patterns of 'fish' evolutionary history remain insufficiently understood and previous studies generally treated each group independently mainly because of their contrasting fossil record composition and corresponding sampling strategies. Because direct reading of palaeodiversity curves is affected by several biases affecting the fossil record, analytical approaches are needed to correct for these biases. In this review, we propose a comprehensive analysis based on comparison of large data sets related to competing phylogenies (including all Recent and fossil taxa) and the fossil record for both groups during the Mesozoic-Cainozoic interval. This approach provides information on the 'fish' fossil record quality and on the corrected 'fish' deep-time phylogenetic palaeodiversity signals, with special emphasis on diversification events. Because taxonomic information is preserved after analytical treatment, identified palaeodiversity events are considered both quantitatively and qualitatively and put within corresponding palaeoenvironmental and biological settings. Results indicate a better fossil record quality for elasmobranchs due to their microfossil-like fossil distribution and their very low diversity in freshwater systems, whereas freshwater actinopterygians are diverse in this realm with lower preservation potential. Several important diversification events are identified at familial and generic levels for elasmobranchs, and marine and freshwater actinopterygians, namely in the Early-Middle Jurassic (elasmobranchs), Late Jurassic (actinopterygians), Early Cretaceous (elasmobranchs, freshwater actinopterygians), Cenomanian (all groups) and the Paleocene-Eocene interval (all groups), the latter two representing the two most exceptional radiations among vertebrates. For each of these events along with the Cretaceous-Paleogene extinction, we provide an in-depth review of the taxa involved and factors that may have influenced the diversity patterns observed. Among these, palaeotemperatures, sea-levels, ocean circulation and productivity as well as continent fragmentation and environment heterogeneity (reef environments) are parameters that largely impacted on 'fish' evolutionary history, along with other biotic constraints.

Mesozoic echinoid diversity in Portugal: Investigating fossil record quality and environmental constraints on a regional scale

Several analyses of diversity through geological time use global, synoptic databases, and this practice often makes it difficult to distinguish true signals in changing diversity from regional-scale sampling and/or geological artefacts. Here we investigate how echinoid diversity changed through the Mesozoic of the Lusitanian basin in Portugal based on a comprehensive, revised database, and seek to distinguish biological signal from geological or environmental constraints. The observed diversity pattern is far from having a defined trend, showing many fluctuations that appear to be linked with gaps in the geological record. This study revealed that, independently of the method used, whether correlation tests or model fitting, the diversity signal is not completely explained by the studied sampling proxies. Among the different proxies, marine facies variation in combination with outcrop area best explains the palaeodiversity curve.

Discriminating signal from noise in the fossil record of early vertebrates reveals cryptic evolutionary history.

The fossil record of early vertebrates has been influential in elucidating the evolutionary assembly of the gnathostome bodyplan. Understanding of the timing and tempo of vertebrate innovations remains, however, mired in a literal reading of the fossil record. Early jawless vertebrates (ostracoderms) exhibit restriction to shallow-water environments. The distribution of their stratigraphic occurrences therefore reflects not only flux in diversity, but also secular variation in facies representation of the rock record. Using stratigraphic, phylogenetic and palaeoenvironmental data, we assessed the veracity of the fossil records of the jawless relatives of jawed vertebrates (Osteostraci, Galeaspida, Thelodonti, Heterostraci). Non-random models of fossil recovery potential using Palaeozoic sea-level changes were used to calculate confidence intervals of clade origins. These intervals extend the timescale for possible origins into the Upper Ordovician; these estimates ameliorate the long ghost lineages inferred for Osteostraci, Galeaspida and Heterostraci, given their known stratigraphic occurrences and stem–gnathostome phylogeny. Diversity changes through the Silurian and Devonian were found to lie within the expected limits predicted from estimates of fossil record quality indicating that it is geological, rather than biological factors, that are responsible for shifts in diversity. Environmental restriction also appears to belie ostracoderm extinction and demise rather than competition with jawed vertebrates.

An analysis of pterosaurian biogeography: implications for the evolutionary history and fossil record quality of the first flying vertebrates

The biogeographical history of pterosaurs has received very little treatment. Here, we present the first quantitative analysis of pterosaurian biogeography based on an event-based parsimony method (Treefitter). This approach was applied to a phylogenetic tree comprising the relationships of 108 in-group pterosaurian taxa, spanning the full range of this clade's stratigraphical and geographical extent. The results indicate that there is no support for the impact of vicariance or coherent dispersal on pterosaurian distributions. However, this group does display greatly elevated levels of sympatry. Although sampling biases and taxonomic problems might have artificially elevated the occurrence of sympatry, we argue that our results probably reflect a genuine biogeographical signal. We propose a novel model to explain pterosaurian distributions: pterosaurs underwent a series of ‘sweep-stakes’ dispersal events (across oceanic barriers in most cases), resulting in the founding of sympatric clusters of taxa. Examination of the spatiotemporal distributions of pterosaurian occurrences indicates that their fossil record is extremely patchy. Thus, while there is likely to be genuine information on pterosaurian diversity and biogeographical patterns in the current data-set, caution is required in its interpretation.

The first half of tetrapod evolution, sampling proxies, and fossil record quality

Abstract The first half of tetrapod evolution witnessed substantial diversification of the clade and several major turnovers and mass extinctions. In the time since their origin, more than 380 Myr ago, to the beginning of the Middle Jurassic 175 Myr ago, tetrapods apparently diversified fitfully, reaching their highest level in the Middle Permian, and showing major diversity declines in the late Moscovian, Early Permian, Wordian, lower Wuchiapingian, end-Permian, lower Anisian, lower Ladinian, Late Triassic (lower Norian to upper Rhaetian), end-Triassic, and Early Jurassic (upper Sinemurian, lower Pliensbachian). Of these diversity drops, only the end-Permian and end-Triassic correspond to recognised mass extinctions, and the late Moscovian and early Norian drops to other previously identified environmental crises. The remainder could be real extinction or turnover events, or partially artefacts of biased sampling. There are strong correlations between formation counts and tetrapod palaeodiversity, suggesting a sampling component in the raw data, but the covariation is not uniform through the whole time span, being poor from Devonian to Middle Permian, and better from Late Permian to Early Jurassic. There is limited evidence for covariation between the tetrapod palaeodiversity time series and other putative sampling metrics, such as specimen completeness, numbers of publications, map areas, gap-bounded sedimentary units, rock volumes, formations, and fossil collections. Modelling by multiple correlations shows that formation count is generally the best explanatory model, either on its own, or combined with other ‘sampling’ time series. However, it is not clear that formation count is independent of the palaeodiversity time series, because rises and falls in both signals could reflect variations in original diversity or in preservation or in sampling.

The Completeness of the Fossil Record of Mesozoic Birds: Implications for Early Avian Evolution

Many palaeobiological analyses have concluded that modern birds (Neornithes) radiated no earlier than the Maastrichtian, whereas molecular clock studies have argued for a much earlier origination. Here, we assess the quality of the fossil record of Mesozoic avian species, using a recently proposed character completeness metric which calculates the percentage of phylogenetic characters that can be scored for each taxon. Estimates of fossil record quality are plotted against geological time and compared to estimates of species level diversity, sea level, and depositional environment. Geographical controls on the avian fossil record are investigated by comparing the completeness scores of species in different continental regions and latitudinal bins. Avian fossil record quality varies greatly with peaks during the Tithonian-early Berriasian, Aptian, and Coniacian–Santonian, and troughs during the Albian-Turonian and the Maastrichtian. The completeness metric correlates more strongly with a ‘sampling corrected’ residual diversity curve of avian species than with the raw taxic diversity curve, suggesting that the abundance and diversity of birds might influence the probability of high quality specimens being preserved. There is no correlation between avian completeness and sea level, the number of fluviolacustrine localities or a recently constructed character completeness metric of sauropodomorph dinosaurs. Comparisons between the completeness of Mesozoic birds and sauropodomorphs suggest that small delicate vertebrate skeletons are more easily destroyed by taphonomic processes, but more easily preserved whole. Lagerstätten deposits might therefore have a stronger impact on reconstructions of diversity of smaller organisms relative to more robust forms. The relatively poor quality of the avian fossil record in the Late Cretaceous combined with very patchy regional sampling means that it is possible neornithine lineages were present throughout this interval but have not yet been sampled or are difficult to identify because of the fragmentary nature of the specimens.

Completeness metrics and the quality of the sauropodomorph fossil record through geological and historical time

Despite increasing concerns about the effect of sampling biases on our reading of the fossil record, few studies have considered the completeness of the fossil remains themselves, and those that have tend to apply non-quantitative measures of preservation quality. Here we outline two new types of metric for quantifying the completeness of the fossil remains of taxa through time, using sauropodomorph dinosaurs as a case study. The “Skeletal Completeness Metric” divides the skeleton up into percentages based on the amount of bone for each region, whereas the “Character Completeness Metric” is based on the number of characters that can be scored for each skeletal element in phylogenetic analyses. For both metrics we calculated the completeness of the most complete individual and of the type specimen. We also calculated how well the taxon as a whole is known from its remains. We then plotted these results against both geological and historical time, and compared curves of the former with fluctuations in sauropodomorph diversity, sea level, and sedimentary rock outcrop area. Completeness through the Mesozoic shows a number of peaks and troughs; the Early Jurassic (Hettangian–Sinemurian) is the interval with highest completeness, whereas the mid-to-Late Cretaceous has completeness levels that are consistently lower than the rest of the Mesozoic. Completeness shows no relationship to rock outcrop area, but it is negatively correlated with sea level during the Jurassic–Early Cretaceous and correlated with diversity in the Cretaceous. Completeness of sauropodomorph type specimens has improved from 1830 to the present, supporting the conclusions of other recent studies. However, when this time interval is partitioned, we find no trend for an increase in completeness from the 1990s onward. Moreover, the 2000s represent one of the poorest decades in terms of average type specimen completeness. These results highlight the need for quantitative methods when assessing fossil record quality through geological time or when drawing conclusions about historical trends in the completeness of taxa. The new metrics may also prove useful as sampling proxies in diversity studies.

Variaciones en la riqueza de macromamíferos de España durante el Neógeno

Changes in the macromammal richness of Spain during the Neogene Abundance and composition of Iberian macromammal faunas has suffered important changes during the Neogene (23 to 2 million years before present). The present paper analizes and describes these changes, also disccusing the taxa involved and their possible causes. Results from the present study point out the existence of an increase in the Iberian species richness from the end of the Lower Miocene to the first half of the Upper Miocene, followed by an strong impoverishment from then on till the Pliocene, interrupted by a temporal increase during the end of the Miocene. Local faunas (individual localities) from the Middle and Upper Miocene are, in some cases, exceptionally diverse, comparable to the richest extant tropical ecosystems. Diversity changes in time are usually explained as a response to climatic changes. However, our analyses point out that many of the observad changes in diversity may be due to differences in the fossil record quality. At locality (local) level caused by differences in the processes of locality formation, while at regional scale due to the number of deposits

Comments on the Relative Advantages of Marsupial and Eutherian Reproduction

Previous articleNext article No AccessNotes and CommentsComments on the Relative Advantages of Marsupial and Eutherian ReproductionStephen R. Morton, Harry F. Recher, Steven D. Thompson, and Richard W. BraithwaiteStephen R. Morton Search for more articles by this author , Harry F. Recher Search for more articles by this author , Steven D. Thompson Search for more articles by this author , and Richard W. Braithwaite Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 120, Number 1Jul., 1982 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/283975 Views: 35Total views on this site Citations: 13Citations are reported from Crossref Copyright 1982 The University of ChicagoPDF download Crossref reports the following articles citing this article:Sergio Daniel Tarquini, Sandrine Ladevèze, Francisco Juan Prevosti The multicausal twilight of South American native mammalian predators (Metatheria, Sparassodonta), Scientific Reports 12, no.11 (Jan 2022).https://doi.org/10.1038/s41598-022-05266-zC. Verity Bennett, Paul Upchurch, Francisco J. Goin, Anjali Goswami Deep time diversity of metatherian mammals: implications for evolutionary history and fossil-record quality, Paleobiology 44, no.22 (Feb 2018): 171–198.https://doi.org/10.1017/pab.2017.34Hayley J. Stannard, Julie M. Old Changes to food intake and nutrition of female red-tailed phascogales (Phascogale calura) during late lactation, Physiology & Behavior 151 (Nov 2015): 398–403.https://doi.org/10.1016/j.physbeh.2015.08.012Craig K. Thompson, Adrian F. Wayne, Stephanie S. Godfrey, R. C. Andrew Thompson Survival, age estimation and sexual maturity of pouch young of the brush-tailed bettong (Bettongia penicillata) in captivity, Australian Mammalogy 37, no.11 (Jan 2015): 29.https://doi.org/10.1071/AM14025Lisa E. Schwanz, Kylie A. Robert Reproductive ecology of wild tammar wallabies in natural and developed habitats on Garden Island, Western Australia, Australian Journal of Zoology 60, no.22 (Jan 2012): 111.https://doi.org/10.1071/ZO12024Josefa Bleu, Jean-François Le Galliard, Sandrine Meylan, Manuel Massot, Patrick S. Fitze Mating does not influence reproductive investment, in a viviparous lizard, Journal of Experimental Zoology Part A: Ecological Genetics and Physiology 315A, no.88 (Jul 2011): 458–464.https://doi.org/10.1002/jez.693Daniel G. Blackburn, Kera K. Weaber, James R. Stewart, Michael B. Thompson Do pregnant lizards resorb or abort inviable eggs and embryos? Morphological evidence from an Australian skink,Pseudemoia pagenstecheri, Journal of Morphology 256, no.22 (Mar 2003): 219–234.https://doi.org/10.1002/jmor.10094S. J. Cork Meeting the energy requirements for lactation in a macropodid marsupial: current nutrition versus stored body reserves, Journal of Zoology 225, no.44 (Mar 2009): 567–576.https://doi.org/10.1111/j.1469-7998.1991.tb04325.xS. D. Thompson Body size, duration of parental care, and the intrinsic rate of natural increase in eutherian and metatherian mammals, Oecologia 71, no.22 (Jan 1987): 201–209.https://doi.org/10.1007/BF00377285 Virginia Hayssen , Robert C. Lacy , and Pamela J. Parker Metatherian Reproduction: Transitional or Transcending?, The American Naturalist 126, no.55 (Oct 2015): 617–632.https://doi.org/10.1086/284443 References, Notes for a Short Course: Studies in Geology 8 (Jul 2017): 199–234.https://doi.org/10.1017/S027116480000097XFrancesco Angelini, Gianfranco Ghiara Reproductive modes and strategies in vertebrate evolution, Bolletino di zoologia 51, no.1-21-2 (Sep 2009): 121–203.https://doi.org/10.1080/11250008409439459Davide Csermely Comparative ethology of reproductive strategies in animals, Bolletino di zoologia 51, no.1-21-2 (Sep 2009): 223–241.https://doi.org/10.1080/11250008409439461