Journal articles: 'Mammals, Fossil'

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Chester, Stephen G. B., Jonathan I. Bloch, Doug M. Boyer, and William A. Clemens. "Oldest known euarchontan tarsals and affinities of Paleocene Purgatorius to Primates." Proceedings of the National Academy of Sciences 112, no. 5 (January 20, 2015): 1487–92. http://dx.doi.org/10.1073/pnas.1421707112.

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Earliest Paleocene Purgatorius often is regarded as the geologically oldest primate, but it has been known only from fossilized dentitions since it was first described half a century ago. The dentition of Purgatorius is more primitive than those of all known living and fossil primates, leading some researchers to suggest that it lies near the ancestry of all other primates; however, others have questioned its affinities to primates or even to placental mammals. Here we report the first (to our knowledge) nondental remains (tarsal bones) attributed to Purgatorius from the same earliest Paleocene deposits that have yielded numerous fossil dentitions of this poorly known mammal. Three independent phylogenetic analyses that incorporate new data from these fossils support primate affinities of Purgatorius among euarchontan mammals (primates, treeshrews, and colugos). Astragali and calcanei attributed to Purgatorius indicate a mobile ankle typical of arboreal euarchontan mammals generally and of Paleocene and Eocene plesiadapiforms specifically and provide the earliest fossil evidence of arboreality in primates and other euarchontan mammals. Postcranial specializations for arboreality in the earliest primates likely played a key role in the evolutionary success of this mammalian radiation in the Paleocene.

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Mayhew, D. F., F. E. Dieleman, A. A. Slupik, L. W. van den Hoek Ostende, and J. W. F. Reumer. "Small mammal assemblages from the Quaternary succession at Moriaanshoofd (Zeeland, the Netherlands) and their significance for correlating the Oosterschelde fauna." Netherlands Journal of Geosciences - Geologie en Mijnbouw 93, no. 3 (April 24, 2014): 119–34. http://dx.doi.org/10.1017/njg.2014.6.

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AbstractWe investigated fossil small mammals from a borehole near Moriaanshoofd (Zeeland, southwest Netherlands) in order to get better insights in the fossil mammal faunas that are found in the subsurface in the southwestern Netherlands, and to investigate the age and provenance of the mammal fauna that is being dredged from the deep tidal gullies in the nearby Oosterschelde estuary. The record in the borehole covers Gelasian (Early Pleistocene) to Holocene deposits, represented by six formations. Thirty-nine specimens of small mammals were obtained from the borehole. These fossils derived from the Early Pleistocene marine Maassluis Formation and from directly overlying deposits of a Late Pleistocene age. During Weichselian times (33–24 ka), a proto-Schelde River shaped the northern Oosterschelde area. The river reworked substantial amounts of Early and Middle Pleistocene deposits. At the base of the Schelde-derived fluvial sequence (regionally described as the Koewacht Formation), Gelasian vertebrate faunas were concentrated in the channel lag. The Late Pleistocene channel lag is almost certainly the main source for the rich Early Pleistocene vertebrate faunas with larger mammals dredged from the Oosterschelde.

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Davies, Thomas W., Mark A. Bell, Anjali Goswami, and Thomas J. D. Halliday. "Completeness of the eutherian mammal fossil record and implications for reconstructing mammal evolution through the Cretaceous/Paleogene mass extinction." Paleobiology 43, no. 4 (August 22, 2017): 521–36. http://dx.doi.org/10.1017/pab.2017.20.

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AbstractThere is a well-established discrepancy between paleontological and molecular data regarding the timing of the origin and diversification of placental mammals. Molecular estimates place interordinal diversification dates in the Cretaceous, while no unambiguous crown placental fossils have been found prior to the end-Cretaceous mass extinction. Here, the completeness of the eutherian fossil record through geological time is evaluated to assess the suggestion that a poor fossil record is largely responsible for the difference in estimates of placental origins. The completeness of fossil specimens was measured using the character completeness metric, which quantifies the completeness of fossil taxa as the percentage of phylogenetic characters available to be scored for any given taxon. Our data set comprised 33 published cladistic matrices representing 445 genera, of which 333 were coded at the species level.There was no significant difference in eutherian completeness across the Cretaceous/Paleogene (K/Pg) boundary. This suggests that the lack of placental mammal fossils in the Cretaceous is not due to a poor fossil record but more likely represents a genuine absence of placental mammals in the Cretaceous. This result supports the “explosive model” of early placental evolution, whereby placental mammals originated around the time of the K/Pg boundary and diversified soon after.No correlation was found between the completeness pattern observed in this study and those of previous completeness studies on birds and sauropodomorph dinosaurs, suggesting that different factors affect the preservation of these groups. No correlations were found with various isotope proxy measures, but Akaike information criterion analysis found that eutherian character completeness metric scores were best explained by models involving the marine-carbonate strontium-isotope ratios (87Sr/86Sr), suggesting that tectonic activity might play a role in controlling the completeness of the eutherian fossil record.

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Brinkman, P. "Bartholomew James Sulivan's discovery of fossil vertebrates in the Tertiary beds of Patagonia." Archives of Natural History 30, no. 1 (April 2003): 56–74. http://dx.doi.org/10.3366/anh.2003.30.1.56.

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While commanding a Royal Navy survey of the Falkland Islands in 1845, Bartholomew James Sulivan discovered and collected fossil mammals at Rio Gallegos, Patagonia. Described the following year by Richard Owen, Sulivan's specimens comprised the first collection taken from what would later be designated the Santa Cruz beds (early-middle Miocene), the most prolific fossil mammal horizon in South America and the oldest discovered by Sulivan's time. Unfortunately, Charles Darwin's conservative estimate of the age of the fossils delayed the full appreciation of Sulivan's discovery. Sulivan was only moderately successful at attracting interest in his discovery among British naturalists. By the time that the first extensive collections of Santa Cruz fossil mammals were made by Argentine paleontologists Carlos and Florentino Ameghino, in the 1890s, Sulivan's pioneering role in the history of South American vertebrate paleontology had been overshadowed and all but forgotten. An examination of Sulivan's experience provides a general model for the process whereby some contributors to science descend from initial fame to lasting obscurity.

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Thewissen, J. G. M. "Fossil Asian Mammals Lite." Journal of Mammalian Evolution 22, no. 2 (September 6, 2014): 279–80. http://dx.doi.org/10.1007/s10914-014-9275-4.

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Candeiro, Carlos Roberto dos Anjos, Cláudia Valéria de Lima, Fernanda Maciel Canile, Stephen Louis Brusatte, Tamires do Carmo Dias, Bruno Martins Ferreira, Raylon da Frota Lopes, and João Eduardo Campelo Rodrigues. "Late Paleozoic, Late Cretaceous and Pleistocene-Holocene reptiles and mammals fauna: a review from Goiás State, Brazil." BOLETÍN GEOLÓGICO Y MINERO 133, no. 4 (December 2022): 37–53. http://dx.doi.org/10.21701/bolgeomin/133.4/002.

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The territory of Goiás State in Central Brazil has yielded reptile fossils from the Permian, Cretaceous and fossil mammals from the Pleistocene-Holocene. Many new fossils have been found during the last years, allowing a better understanding of community structure and faunal evolution during these time intervals. In this study we present an updated synthesis of the reptilian and mammal faunas of Goiás. Tetrapod fossils have been found in the Paraná Basin rocks (Permian Passa Dois and Upper Cretaceous Bauru groups) in the Southern Goiás State since 1935. Goiás state fossils have been recorded in eight municipalities, and include mollusks, turtles, mesosaurids, crocodiliforms, dinosaurs, and mammals. This paleofauna is exclusively comprised of classic South American taxa that are also found in other former parts of Gondwana.

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dos Reis, Mario, Philip C. J. Donoghue, and Ziheng Yang. "Neither phylogenomic nor palaeontological data support a Palaeogene origin of placental mammals." Biology Letters 10, no. 1 (January 2014): 20131003. http://dx.doi.org/10.1098/rsbl.2013.1003.

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O'Leary et al . (O'Leary et al. 2013 Science 339 , 662–667. ( doi:10.1126/science.1229237 )) performed a fossil-only dating analysis of mammals, concluding that the ancestor of placentals post-dated the Cretaceous–Palaeogene boundary, contradicting previous palaeontological and molecular studies that placed the ancestor in the Cretaceous. They incorrectly used fossil ages as species divergence times for crown groups, while in fact the former should merely form minimum-age bounds for the latter. Statistical analyses of the fossil record have shown that crown groups are significantly older than the oldest ingroup fossil, so that fossils do not directly reflect the true ages of clades. Here, we analyse a 20 million nucleotide genome-scale alignment in conjunction with a probabilistic interpretation of the fossil ages from O'Leary et al. Our combined analysis of fossils and molecules demonstrates that Placentalia originated in the Cretaceous.

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Samonds, Karen E. "Fossil Mammals of South America." Journal of Mammalogy 99, no. 1 (November 13, 2017): 294–95. http://dx.doi.org/10.1093/jmammal/gyx145.

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Smith, Vincent S., Tom Ford, Kevin P. Johnson, Paul C. D. Johnson, Kazunori Yoshizawa, and Jessica E. Light. "Multiple lineages of lice pass through the K–Pg boundary." Biology Letters 7, no. 5 (April 6, 2011): 782–85. http://dx.doi.org/10.1098/rsbl.2011.0105.

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For modern lineages of birds and mammals, few fossils have been found that predate the Cretaceous–Palaeogene (K–Pg) boundary. However, molecular studies using fossil calibrations have shown that many of these lineages existed at that time. Both birds and mammals are parasitized by obligate ectoparasitic lice (Insecta: Phthiraptera), which have shared a long coevolutionary history with their hosts. Evaluating whether many lineages of lice passed through the K–Pg boundary would provide insight into the radiation of their hosts. Using molecular dating techniques, we demonstrate that the major louse suborders began to radiate before the K–Pg boundary. These data lend support to a Cretaceous diversification of many modern bird and mammal lineages.

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Viglino, Mariana, Ana M. Valenzuela-Toro, Aldo Benites-Palomino, Atzcalli Ehécatl Hernández-Cisneros, Carolina S. Gutstein, Gabriel Aguirre-Fernández, Jorge Velez-Juarbe, Mario A. Cozzuol, Monica R. Buono, and Carolina Loch. "Aquatic mammal fossils in Latin America – a review of records, advances and challenges in research in the last 30 years." Latin American Journal of Aquatic Mammals 18, no. 1 (January 27, 2023): 50–65. http://dx.doi.org/10.5597/lajam00295.

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Records of aquatic mammal fossils (e.g. cetaceans, pinnipeds, sirenians, mustelids, and desmostylians) from Latin America (Mexico to Tierra del Fuego, including Antartica) span since the mid-1800s. Aquatic mammal fossils received little attention from the scientific community, with most of the first studies conducted by Northern Hemisphere researchers. Over the last 30 years, paleontological research in Latin America has increased considerably, with descriptions of several new species and revisions of published original records. The Latin American fossil record of marine mammals spans from the Eocene to the Pleistocene, with formations and specimens of global significance. All three main groups of cetaceans are represented in the continent (Archaeoceti, Mysticeti, and Odontoceti). Pinnipedia are represented by the families Otariidae and Phocidae, with records starting in the Middle Miocene. Both living families of Sirenia (Trichechidae and Dugongidae) are recorded. While less common, but still relevant, records of desmostylians and mustelids are known from Oligocene and Miocene deposits. This review provides a summary of the aquatic mammals known to date, with a special focus on the advances and developments of the last 30 years, since Cozzuol’s (1996) review of the South American fossil record. An up-to-date complete list of species based on the literature and unpublished data is also provided. The study also provides future directions for paleontological research in Latin America, and discusses the challenges and opportunities in the field, including the emergence of a strong new generation of Latin American researchers, many of whom are women.

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Guillerme, Thomas, and Natalie Cooper. "Assessment of available anatomical characters for linking living mammals to fossil taxa in phylogenetic analyses." Biology Letters 12, no. 5 (May 2016): 20151003. http://dx.doi.org/10.1098/rsbl.2015.1003.

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Analyses of living and fossil taxa are crucial for understanding biodiversity through time. The total evidence method allows living and fossil taxa to be combined in phylogenies, using molecular data for living taxa and morphological data for living and fossil taxa. With this method, substantial overlap of coded anatomical characters among living and fossil taxa is vital for accurately inferring topology. However, although molecular data for living species are widely available, scientists generating morphological data mainly focus on fossils. Therefore, there are fewer coded anatomical characters in living taxa, even in well-studied groups such as mammals. We investigated the number of coded anatomical characters available in phylogenetic matrices for living mammals and how these were phylogenetically distributed across orders. Eleven of 28 mammalian orders have less than 25% species with available characters; this has implications for the accurate placement of fossils, although the issue is less pronounced at higher taxonomic levels. In most orders, species with available characters are randomly distributed across the phylogeny, which may reduce the impact of the problem. We suggest that increased morphological data collection efforts for living taxa are needed to produce accurate total evidence phylogenies.

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Young, C. C. "On Some Fossil Mammals from Yünnan*." Bulletin of the Geological Society of China 11, no. 4 (May 29, 2009): 383–94. http://dx.doi.org/10.1111/j.1755-6724.1932.mp11004004.x.

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Agadzhanyan, A. K. "THE MAIN DIRECTIONS OF MAMMALIAN EVOLUTION." Зоологический журнал 102, no. 4 (April 1, 2023): 408–30. http://dx.doi.org/10.31857/s0044513423040037.

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Modern views on the origin and early evolution of mammals are presented. The work uses the material accumulated by the author on the morphology of modern and fossil monotremes, marsupials and placentals. Data on Mesozoic mammals, including those obtained in recent years, are summarized. A model of the mechanism of morphogenetic transformations during the evolutionary development of Mammalia is proposed. An overview of the main directions of the formation of mammals from the Late Triassic to the Cenozoic is given.

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Rzebik-Kowalska, Barbara, and Leonid I. Rekovets. "Recapitulation of data on Ukrainian fossil insectivore mammals (Eulipotyphla, Insectivora, Mammalia)." Acta Zoologica Cracoviensia 58, no. 2 (December 31, 2015): 137–71. http://dx.doi.org/10.3409/azc.58_2.137.

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Jerison, Harry J. "Digitized Fossil Brains: Neocorticalization." Biolinguistics 6, no. 3-4 (November 28, 2012): 383–92. http://dx.doi.org/10.5964/bioling.8929.

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This report is based on 3D digital scans of endocasts of 110 species of fossil mammals and 35 species of living mammals. It presents direct evidence of the last 60 million years of brain evolution. Endocasts are casts of the cranial cavity. They are brainlike in size and shape, and their surface features can be named as if they were brain structures. Although endocast data are restricted to outer surfaces of brains, a few inferences about inner structure are possible. Neocortex in the forebrain, for example, is identifiable and measurable as cerebral forebrain on the endocast dorsal to the rhinal fissure. An important result in this report is that surface area of neocortex as identified on endocasts appears to have reached a maximum of about 80% of the total endocast surface area in anthropoid primates including humans. This may be a fundamental limitation in brain size. The average neocorticalization percentage for mammals as a whole rose from about 20% to about 50% of the surface area during the 60 million years covered by this analysis. Neocorticalization is associated with the evolution of higher mental processes, including the evolution of language as a hominin specialization. The limitation of the increase in relative amount of neocortex is similar in all anthropoids. Neocortex is greater in absolute area in living humans because the total size of the hominin brain is so much larger than in other primates.

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McDowell, Matthew C., and Graham C. Medlin. "Natural Resource Management implications of the pre-European non-volant mammal fauna of the southern tip of Eyre Peninsula, South Australia." Australian Mammalogy 32, no. 2 (2010): 87. http://dx.doi.org/10.1071/am09020.

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Sinkholes and coastal caves located in, around and between the Coffin Bay and Lincoln National Parks were surveyed for pre-European fossils, which were collected from or just below the sediment surface. Twenty-four pre-European fossil samples, including eight already in the collections of the South Australian Museum, were analysed and 25 native and five introduced species of non-volant mammal were identified. Native and introduced species were often found together, indicating that the sites have accumulated mammal remains in both pre- and post-European times. Only four of the non-volant native mammals recovered are known to be extant in the study area today: Lasiorhinus latifrons, Macropus fuliginosus, Cercartetus concinnus and Rattus fuscipes. In contrast, 20 native species recorded have been extirpated and one (Potorous platyops) is now extinct. C. concinnus was recorded from only one of the fossil assemblages but is known to be widespread in the study area today. This may indicate recent vegetation change related to European land management practices and have implications for natural resource management in the area.

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Barnes, Lawrence G., Daryl P. Domning, and Clayton E. Ray. "STATUS OF STUDIES ON FOSSIL MARINE MAMMALS." Marine Mammal Science 1, no. 1 (January 1985): 15–53. http://dx.doi.org/10.1111/j.1748-7692.1985.tb00530.x.

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PROTHERO, Donald R. "Species longevity in North American fossil mammals." Integrative Zoology 9, no. 4 (August 2014): 383–93. http://dx.doi.org/10.1111/1749-4877.12054.

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Plotnick, Roy E., and Karen A. Koy. "The Anthropocene fossil record of terrestrial mammals." Anthropocene 29 (March 2020): 100233. http://dx.doi.org/10.1016/j.ancene.2019.100233.

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Liddle, Nerida R., Matthew C. McDowell, and Gavin J. Prideaux. "Insights into the pre-European mammalian fauna of the southern Flinders Ranges, South Australia." Australian Mammalogy 40, no. 2 (2018): 262. http://dx.doi.org/10.1071/am17035.

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Many Australian mammal species have suffered significant declines since European colonisation. During the first century of settlement, information on species distribution was rarely recorded. However, fossil accumulations can assist the reconstruction of historical distributions. We examine a fossil vertebrate assemblage from Mair’s Cave, one of few known from the southern Flinders Ranges, South Australia. The Mair’s Cave assemblage was dominated by mammals but also included birds and reptiles. Of the 18 mammals recovered, two have not previously been recorded from the southern Flinders Ranges, at least one is extinct and seven are recognised as threatened nationally. Characteristics of the assemblage suggest that it was accumulated by a Tyto owl species. Remains of Tyto delicatula and a larger unidentified owl were recovered from the assemblage. Most mammals identified from the assemblage presently occupy Australia’s semiarid zone, but a single specimen of the broad-toothed rat (Mastacomys fuscus), which primarily occurs in high-moisture, low-temperature environments was also recovered. This suggests either that the southern Flinders Ranges once experienced higher past precipitation, or that M. fuscus can tolerate a broader climatic range than its current distribution suggests. Our study contributes new knowledge on the biogeography and ecology of several mammal species, data useful for helping to refine restoration targets.

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Torres, Jesús M., Concepción Borja, Luis Gibert, Francesc Ribot, and Enrique G. Olivares. "Twentieth-Century Paleoproteomics: Lessons from Venta Micena Fossils." Biology 11, no. 8 (August 6, 2022): 1184. http://dx.doi.org/10.3390/biology11081184.

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Proteomics methods can identify amino acid sequences in fossil proteins, thus making it possible to determine the ascription or proximity of a fossil to other species. Before mass spectrometry was used to study fossil proteins, earlier studies used antibodies to recognize their sequences. Lowenstein and colleagues, at the University of San Francisco, pioneered the identification of fossil proteins with immunological methods. His group, together with Olivares’s group at the University of Granada, studied the immunological reactions of proteins from the controversial Orce skull fragment (VM-0), a 1.3-million-year-old fossil found at the Venta Micena site in Orce (Granada province, southern Spain) and initially assigned to a hominin. However, discrepancies regarding the morphological features of the internal face of the fossil raised doubts about this ascription. In this article, we review the immunological analysis of the proteins extracted from VM-0 and other Venta Micena fossils assigned to hominins and to other mammals, and explain how these methods helped to determine the species specificity of these fossils and resolve paleontological controversies.

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MacFadden, Bruce J., and Richard C. Hulbert. "Calibration of mammoth (Mammuthus) dispersal into North America using rare earth elements of Plio-Pleistocene mammals from Florida." Quaternary Research 71, no. 1 (January 2009): 41–48. http://dx.doi.org/10.1016/j.yqres.2008.04.008.

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AbstractThe first appearance of mammoth (Mammuthus) is currently used to define the beginning of the Irvingtonian North American Land Mammal Age at about 1.4 Ma. Thereafter, mammoth fossils are common and widespread in North America until the end of the Pleistocene. In contrast to this generally accepted biochronology, recent reports have asserted that mammoth occurs in late Pliocene (ca. 2.5 Ma) alluvium from the Santa Fe River of northern Florida. The supposedly contemporaneous late Pliocene fossil assemblage from the Santa Fe River that produced the mammoth specimens actually consists of a mixture of diagnostic Blancan (late Pliocene) and late Rancholabrean (latest Pleistocene) species. Fossil bones and teeth of the two mammalian faunas mixed together along the Santa Fe River have significantly different rare earth element (REE) signatures. The REE signatures of mammoth are indistinguishable from those of Rancholabrean mammals, yet they are different from those of diagnostic Blancan vertebrates from these same temporally mixed faunas of the Santa Fe River. Thus, no evidence for late Pliocene mammoth exists in Florida, and mammoth fossils remain reliable biochronological indicators for Irvingtonian and Rancholabrean terrestrial sequences throughout mid- and lower-latitude North America.

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Near, Thomas J., and Michael J. Sanderson. "Assessing the quality of molecular divergence time estimates by fossil calibrations and fossil–based model selection." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 359, no. 1450 (October 29, 2004): 1477–83. http://dx.doi.org/10.1098/rstb.2004.1523.

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Estimates of species divergence times using DNA sequence data are playing an increasingly important role in studies of evolution, ecology and biogeography. Most work has centred on obtaining appropriate kinds of data and developing optimal estimation procedures, whereas somewhat less attention has focused on the calibration of divergences using fossils. Case studies with multiple fossil calibration points provide important opportunities to examine the divergence time estimation problem in new ways. We discuss two cross–validation procedures that address different aspects of inference in divergence time estimation. ‘Fossil cross–validation’ is a procedure used to identify the impact of different individual calibrations on overall estimation. This can identify fossils that have an exceptionally large error effect and may warrant further scrutiny. ‘Fossil–based model cross–validation’ is an entirely different procedure that uses fossils to identify the optimal model of molecular evolution in the context of rate smoothing or other inference methods. Both procedures were applied to two recent studies: an analysis of monocot angiosperms with eight fossil calibrations and an analysis of placental mammals with nine fossil calibrations. In each case, fossil calibrations could be ranked from most to least influential, and in one of the two studies, the fossils provided decisive evidence about the optimal molecular evolutionary model.

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Tseng, Z. Jack, Adolfo Pacheco-Castro, Oscar Carranza-Castañeda, José Jorge Aranda-Gómez, Xiaoming Wang, and Hilda Troncoso. "Discovery of the fossil otter Enhydritherium terraenovae (Carnivora, Mammalia) in Mexico reconciles a palaeozoogeographic mystery." Biology Letters 13, no. 6 (June 2017): 20170259. http://dx.doi.org/10.1098/rsbl.2017.0259.

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The North American fossil otter Enhydritherium terraenovae is thought to be partially convergent in ecological niche with the living sea otter Enhydra lutris , both having low-crowned crushing teeth and a close association with marine environments. Fossil records of Enhydritherium are found in mostly marginal marine deposits in California and Florida; despite presence of very rich records of fossil terrestrial mammals in contemporaneous localities inland, no Enhydritherium fossils are hitherto known in interior North America. Here we report the first occurrence of Enhydritherium outside of Florida and California, in a land-locked terrestrial mammal fauna of the upper Miocene deposits of Juchipila Basin, Zacatecas State, Mexico. This new occurrence of Enhydritherium is at least 200 km from the modern Pacific coastline, and nearly 600 km from the Gulf of Mexico. Besides providing further evidence that Enhydritherium was not dependent on coastal marine environments as originally interpreted, this discovery leads us to propose a new east-to-west dispersal route between the Florida and California Enhydritherium populations through central Mexico. The proximity of the fossil locality to nearby populations of modern neotropical otters Lontra longicaudis suggests that trans-Mexican freshwater corridors for vertebrate species in riparian habitats may have persisted for a prolonged period of time, pre-dating the Great American Biotic Interchange.

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Chitimia-Dobler, Lidia, Timo Pfeffer, and Jason A. Dunlop. "Haemaphysalis cretacea a nymph of a new species of hard tick in Burmese amber." Parasitology 145, no. 11 (April 12, 2018): 1440–51. http://dx.doi.org/10.1017/s0031182018000537.

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AbstractThe first fossil potentially assignable to the extant hard tick genus Haemaphysalis CL Koch (1844) (Ixodida: Ixodidae) is described from the Late Cretaceous (ca. 99 Ma) Burmese amber of Myanmar. Haemaphysalis (Alloceraea) cretacea sp. nov. is the oldest and only fossil representative of this genus; living members of which predominantly feed on mammals. Their typical hosts are known since at least the Jurassic and the discovery of a mid-Cretaceous parasite, which might have fed on mammals raises again the question of to what extent ticks are coupled to their (modern) host groups. An inferred Triassic split of Argasidae (soft ticks) into the bird-preferring Argasinae and mammal-preferring Ornithodorinae dates to about the time when dinosaurs (later including birds) and mammaliaforms as potential hosts were emerging. Ixodidae may have split into Prostriata and Metastriata shortly after the end-Permian mass extinction, an event which fundamentally altered the terrestrial vertebrate fauna. Prostriata (the genus Ixodes) prefer birds and mammals today, and some may have used groups like cynodonts in the Triassic. Basal metastriate ticks (e.g. Amblyomma) prefer reptiles, but derived metastriates (including Haemaphysalis) again prefer mammals. Here, we may be looking at a younger (Cretaceous?) shift associated with more recent mammalian radiations.

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de Bruijn, H., R. Daams, G. Daxner-Höck, V. Fahlbusch, L. Ginsburg, P. Mein, J. Marles, et al. "Report of the RCMNS working group on fossil mammals, Reisensburg 1990." Newsletters on Stratigraphy 26, no. 2-3 (April 22, 1992): 65–118. http://dx.doi.org/10.1127/nos/26/1992/65.

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Yuan, Chong-Xi, Qiang Ji, Qing-Jin Meng, Alan R. Tabrum, and Zhe-Xi Luo. "Earliest Evolution of Multituberculate Mammals Revealed by a New Jurassic Fossil." Science 341, no. 6147 (August 15, 2013): 779–83. http://dx.doi.org/10.1126/science.1237970.

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Multituberculates were successful herbivorous mammals and were more diverse and numerically abundant than any other mammal groups in Mesozoic ecosystems. The clade also developed diverse locomotor adaptations in the Cretaceous and Paleogene. We report a new fossil skeleton from the Late Jurassic of China that belongs to the basalmost multituberculate family. Dental features of this new Jurassic multituberculate show omnivorous adaptation, and its well-preserved skeleton sheds light on ancestral skeletal features of all multituberculates, especially the highly mobile joints of the ankle, crucial for later evolutionary success of multituberculates in the Cretaceous and Paleogene.

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Beck, Robin M. D., and Charles Baillie. "Improvements in the fossil record may largely resolve current conflicts between morphological and molecular estimates of mammal phylogeny." Proceedings of the Royal Society B: Biological Sciences 285, no. 1893 (December 12, 2018): 20181632. http://dx.doi.org/10.1098/rspb.2018.1632.

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Phylogenies of mammals based on morphological data continue to show several major areas of conflict with the current consensus view of their relationships, which is based largely on molecular data. This raises doubts as to whether current morphological character sets are able to accurately resolve mammal relationships. We tested this under a hypothetical ‘best case scenario’ by using ancestral state reconstruction (under both maximum parsimony and maximum likelihood) to infer the morphologies of fossil ancestors for all clades present in a recent comprehensive DNA sequence-based phylogeny of mammals, and then seeing what effect the subsequent inclusion of these predicted ancestors had on unconstrained phylogenetic analyses of morphological data. We found that this resulted in topologies that are highly congruent with the current consensus phylogeny, at least when the predicted ancestors are assumed to be well preserved and densely sampled. Most strikingly, several analyses recovered the monophyly of clades that have never been found in previous morphology-only studies, such as Afrotheria and Laurasiatheria. Our results suggest that, at least in principle, improvements in the fossil record—specifically the discovery of fossil taxa that preserve the ancestral or near-ancestral morphologies of the nodes in the current consensus—may be sufficient to largely reconcile morphological and molecular estimates of mammal phylogeny, even using current morphological character sets.

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Prothero, Donald R. "Mammalian Evolution." Short Courses in Paleontology 7 (1994): 238–70. http://dx.doi.org/10.1017/s2475263000001343.

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The evolution of certain mammalian lineages has become the favorite examples of nearly every introductory textbook in historical geology, paleontology, and evolutionary biology. The evolution of the horse is the most frequently used, since it emerged in 1851 and has been reproduced many times in nearly 150 years (see Gould, 1987, and MacFadden, 1992). Occasionally, one sees a revival of one of Osborn's (1929) evolutionary sequences of brontotheres, and some books may show a sequence of mammoths and mastodonts. In most historical geology books, the discussion of fossil mammals usually consists of just these selected examples, since the authors seem to think that a fuller account of Cenozoic mammal evolution is beyond the level of their readers. Children's books, trade books, and museum displays typically show little more than the evolution of the horse and few selected pictures of spectacular beasts such as saber-toothed cats, ground sloths, mammoths, and the gigantic hornless rhinocerosParaceratherium(called by the obsolete namesBaluchitheriumorIndricotheriumin virtually every caption). Given these conditions, one cannot fault students or the general public for thinking that only horses have a good fossil record, or that there are no other well-studied groups of fossil mammals.

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Marenssi, S. A., M. A. Reguero, S. N. Santillana, and S. F. Vizcaino. "Eocene land mammals from Seymour Island, Antarctica: palaeobiogeographical implications." Antarctic Science 6, no. 1 (March 1994): 3–15. http://dx.doi.org/10.1017/s0954102094000027.

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Middle Eocene land mammals from La Meseta Formation, Seymour (Marambio) Island are reviewed. A taxonomically diverse fossil land-vertebrate assemblage with small and medium-size mammals has been recovered from four localities. The depositional setting is shallow marine and most of the mammal-bearing beds are in reworked, moderate to high energy subtidal facies. The characteristics of these mammals not only confirm but also strengthen the biogeographical relationships between southern South America (Patagonian Province) and the Antarctic Peninsula during the Paleogene and rule out the possibility of a major barrier between these areas. The Antarctic ungulates (Astrapotheria and ?Litopterna) are plesiomorphics in retaining low crowned cheek teeth and are more similar to those from the Pancasamayoran local faunas of southern South America (Patagonia).

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Tammone, Mauro N., Eileen A. Lacey, and Ulyses FJ Pardiñas. "Dramatic recent changes in small mammal assemblages from Northern Patagonia: A caution for paleoenvironmental reconstructions." Holocene 30, no. 11 (July 14, 2020): 1579–90. http://dx.doi.org/10.1177/0959683620941096.

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Temporal differences in fossil assemblages of small mammals can generate important insights into associated environmental conditions. Moreover, by including modern assemblages in such comparisons, it may also be possible to identify the effects of recent human colonization on mammal communities and their habitats. To explore potential signals of European colonization in northwestern Patagonia, we compared fossil and modern assemblages of small mammals from two newly characterized paleontological sites in the Limay Valley region of Río Negro Province, Argentina. The material analyzed consisted of 18 species of small-bodied terrestrial mammals identified from a sample of 27,992 specimens. Fossil assemblages dating from 6453 to 1002 calibrated years before present were relatively stable in taxonomic composition and displayed only minor differences in relative species abundances. In contrast, the modern assemblages examined were clearly distinct, containing a different suite of numerically dominant taxa and lacking three previously abundant grassland species that are presumed to have gone extinct in the vicinity of our study sites. We suggest that these changes reflect substantial post-colonization modifications of surrounding landscapes, including establishment of pine plantations, changes in fire regimes, and introductions of livestock and invasive species of plants. If correct, this supposition raises important concerns regarding the use of modern assemblages as a baseline for reconstructing paleoenvironmental conditions. To avoid potential misinterpretations associated with the use of modern faunal assemblages, we suggest two potential alternative strategies for inferring temporal changes in environmental conditions.

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Boev, Zlatozar, Nedko Nedyalkov, Dilian Georgiev, and Nikolai Spassov. "Late Pleistocene birds and mammals from the Kiliite Cave (central Stara Planina Mts – central North Bulgaria)." Geologica Balcanica 53, no. 1 (March 28, 2024): 105–15. http://dx.doi.org/10.52321/geolbalc.53.1.105.

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The studied fossil material of birds and mammals from a new Late Pleistocene site in the Stara Planina (Balkan) mountain range is herein presented. The age of the site was determined on the basis of the taxonomic composition of the mammal fauna. A total of 28 taxa (10 birds, 15 small and 3 large mammals) have been identified from 103 bone/teeth specimens. Of these, 14.3% of the established species are extinct/disappeared – Perdix palaeoperdix, Megaloceros giganteus, Ursus ingressus and Cuon sp. Most numerous are the remains of Microtus arvalis-agrestis, representing 42.7% of all finds.

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Gearty, William, Craig R. McClain, and Jonathan L. Payne. "Energetic tradeoffs control the size distribution of aquatic mammals." Proceedings of the National Academy of Sciences 115, no. 16 (March 26, 2018): 4194–99. http://dx.doi.org/10.1073/pnas.1712629115.

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Four extant lineages of mammals have invaded and diversified in the water: Sirenia, Cetacea, Pinnipedia, and Lutrinae. Most of these aquatic clades are larger bodied, on average, than their closest land-dwelling relatives, but the extent to which potential ecological, biomechanical, and physiological controls contributed to this pattern remains untested quantitatively. Here, we use previously published data on the body masses of 3,859 living and 2,999 fossil mammal species to examine the evolutionary trajectories of body size in aquatic mammals through both comparative phylogenetic analysis and examination of the fossil record. Both methods indicate that the evolution of an aquatic lifestyle is driving three of the four extant aquatic mammal clades toward a size attractor at ∼500 kg. The existence of this body size attractor and the relatively rapid selection toward, and limited deviation from, this attractor rule out most hypothesized drivers of size increase. These three independent body size increases and a shared aquatic optimum size are consistent with control by differences in the scaling of energetic intake and cost functions with body size between the terrestrial and aquatic realms. Under this energetic model, thermoregulatory costs constrain minimum size, whereas limitations on feeding efficiency constrain maximum size. The optimum size occurs at an intermediate value where thermoregulatory costs are low but feeding efficiency remains high. Rather than being released from size pressures, water-dwelling mammals are driven and confined to larger body sizes by the strict energetic demands of the aquatic medium.

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Hunter, John P. "Evolution at All Scales in the Vertebrate Fossil Record." Paleontological Society Special Publications 11 (2002): 165–78. http://dx.doi.org/10.1017/s2475262200009898.

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The fossil record of vertebrates provides abundant evidence for both the fact and the theory of evolution (Carroll, 1997; Prothero and Schoch, 1994). In support of the fact that evolution has indeed occurred, the vertebrate fossil record clearly documents evolutionary change along lineages, that is, along direct lines of ancestors and descendents. The fossil record also shows step-wise evolutionary changes resulting in the emergence of new kinds of vertebrates from pre-existing kinds—for example, the origin of mammals from the “mammal-like” reptiles. In support of the theory that natural selection, in particular, has been largely responsible for evolutionary change, the fossil record shows that the numerous “transitional” forms that lived in the past—far from being nonviable “monsters”—were functionally integrated organisms that were well adapted to their ecological roles. Finally, the vertebrate fossil record preserves certain large-scale phenomena, such as radiations and trends, which show that evolutionary forces can act over very large time scales.

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Hunter, John P. "Evolution at all Scales in the Vertebrate Fossil Record." Paleontological Society Special Publications 9 (1999): 203–20. http://dx.doi.org/10.1017/s247526220001409x.

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The fossil record of vertebrates provides abundant evidence for both the fact and the theory of evolution (Carroll, 1997; Prothero and Schoch, 1994). In support of the fact that evolution has indeed occurred, the vertebrate fossil record clearly documents evolutionary change along lineages, that is, along direct lines of ancestors and descendents. The fossil record also shows step-wise evolutionary changes resulting in the emergence of new kinds of vertebrates from pre-existing kinds, for example, the origin of mammals from the “mammal-like” reptiles. In support of the theory that natural selection, in particular, has been largely responsible for evolutionary change, the fossil record shows that the numerous “transitional” forms that lived in the past — far from being nonviable “monsters” — were functionally integrated organisms that were well adapted to their ecological roles. Finally, the vertebrate fossil record preserves certain large-scale phenomena, such as radiations and trends, which show that evolutionary forces can act over very large time scales.

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Colleary, Caitlin, Andrei Dolocan, James Gardner, Suresh Singh, Michael Wuttke, Renate Rabenstein, Jörg Habersetzer, et al. "Chemical, experimental, and morphological evidence for diagenetically altered melanin in exceptionally preserved fossils." Proceedings of the National Academy of Sciences 112, no. 41 (September 28, 2015): 12592–97. http://dx.doi.org/10.1073/pnas.1509831112.

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In living organisms, color patterns, behavior, and ecology are closely linked. Thus, detection of fossil pigments may permit inferences about important aspects of ancient animal ecology and evolution. Melanin-bearing melanosomes were suggested to preserve as organic residues in exceptionally preserved fossils, retaining distinct morphology that is associated with aspects of original color patterns. Nevertheless, these oblong and spherical structures have also been identified as fossilized bacteria. To date, chemical studies have not directly considered the effects of diagenesis on melanin preservation, and how this may influence its identification. Here we use time-of-flight secondary ion mass spectrometry to identify and chemically characterize melanin in a diverse sample of previously unstudied extant and fossil taxa, including fossils with notably different diagenetic histories and geologic ages. We document signatures consistent with melanin preservation in fossils ranging from feathers, to mammals, to amphibians. Using principal component analyses, we characterize putative mixtures of eumelanin and phaeomelanin in both fossil and extant samples. Surprisingly, both extant and fossil amphibians generally exhibit melanosomes with a mixed eumelanin/phaeomelanin composition rather than pure eumelanin, as assumed previously. We argue that experimental maturation of modern melanin samples replicates diagenetic chemical alteration of melanin observed in fossils. This refutes the hypothesis that such fossil microbodies could be bacteria, and demonstrates that melanin is widely responsible for the organic soft tissue outlines in vertebrates found at exceptional fossil localities, thus allowing for the reconstruction of certain aspects of original pigment patterns.

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Raia, P., F. Carotenuto, F. Passaro, D. Fulgione, and M. Fortelius. "Ecological Specialization in Fossil Mammals Explains Cope’s Rule." American Naturalist 179, no. 3 (March 2012): 328–37. http://dx.doi.org/10.1086/664081.

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DeSantis, Larisa R. G. "Dental microwear textures: reconstructing diets of fossil mammals." Surface Topography: Metrology and Properties 4, no. 2 (March 22, 2016): 023002. http://dx.doi.org/10.1088/2051-672x/4/2/023002.

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Pickford, Martin. "A Fossil History of Southern African Land Mammals." Transactions of the Royal Society of South Africa 74, no. 3 (August 1, 2019): 304–5. http://dx.doi.org/10.1080/0035919x.2019.1639565.

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Covert, Herbert H., Mark W. Hamrick, Trinh Dzanh, and Kevin C. Mckinney. "Fossil mammals from the Late Miocene of Vietnam." Journal of Vertebrate Paleontology 21, no. 3 (August 22, 2001): 633–36. http://dx.doi.org/10.1671/0272-4634(2001)021[0633:fmftlm]2.0.co;2.

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Fortelius, Mikael, Aristides Gionis, Jukka Jernvall, and Heikki Mannila. "Spectral ordering and biochronology of European fossil mammals." Paleobiology 32, no. 2 (March 2006): 206–14. http://dx.doi.org/10.1666/04087.1.

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Harvey, Virginia L., Victoria M. Egerton, Andrew T. Chamberlain, Phillip L. Manning, William I. Sellers, and Michael Buckley. "Interpreting the historical terrestrial vertebrate biodiversity of Cayman Brac (Greater Antilles, Caribbean) through collagen fingerprinting." Holocene 29, no. 4 (January 29, 2019): 531–42. http://dx.doi.org/10.1177/0959683618824793.

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Cayman Brac (Cayman Islands) lies within the Caribbean Islands Biodiversity Hotspot, an epicenter of high biodiversity and endemism. However, all endemic terrestrial mammals on the Cayman Islands are now extinct, following post-1500 AD human colonization of the islands. Introduced rodents and domesticated mammals now exclusively represent this facet of terrestrial fauna on the Cayman Islands, and are a likely cause of endemic species loss on the islands. Cayman Brac has numerous caves and rock fissures that offer protection to a naturally accumulated ensemble of vertebrate sub-fossil bone remains, documenting modifications in island biodiversity through the Holocene. In this study, we showcase the first molecular faunal survey undertaken on sub-fossil remains from the Cayman Islands, using collagen fingerprinting for taxonomic identification of the cave skeletal deposits collected from a single cave system, Green Cave on Cayman Brac. Collagen type (I) extracts from 485 bone fragments were analyzed to determine faunal identity and assemblage composition. A total of 76% of the collagen fingerprint-yielding samples were mammalian in origin, 67% of which were identified as invasive murid rodents. Here, we present mass spectral biomarkers for the endemic terrestrial mammal fauna of Cayman Brac, including the extinct capromyid rodents, Capromys and Geocapromys (Rodentia: Capromyidae), alongside commentary on the composition of the sub-fossil bone assemblage between the five distinct depositional chambers that comprise Green Cave. Collagen (I) provides a key service in taxonomic identification and mapping of macroevolutionary trends, and these results suggest a pivotal role for murid rodents in the competition and extinction of terrestrial endemic mammals from the Cayman Islands.

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Miller, Wade, and Dee Hall. "Earliest History of Vertebrate Paleontology in Utah: Last Half of the 19th Century." Earth Sciences History 9, no. 1 (January 1, 1990): 28–33. http://dx.doi.org/10.17704/eshi.9.1.72266661544wp27v.

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Aside from the recorded travels of Juan de Rivera in 1765 and the Dominguez-Escalante party in 1776, the earliest reports involving explorations into Utah were mostly those for proposed railroad lines and trade routes, or for general knowledge of the poorly known Western Territories (1840s to 1870s). These explorations were usually conducted under the auspices of the United States Army. Scientists, including geologists/paleontologists, commonly accompanied the survey parties. The first surveys whose prime objectives were to study geology and topography were commissioned by Congress in 1867. The earliest discovery of a vertebrate fossil in Utah apparently took place on the J. N. Macomb expedition of 1859 (which generally followed the Old Spanish Trail), when J. S. Newberry collected dinosaur bones in the southeastern part of the state. F. V. Hayden's 1870 survey may have extended into northernmost Utah. It is possible that a few of the Eocene age fossils which were reported by him from southernmost Wyoming, came from here. Fossils collected during the Hayden survey prompted a vertebrate fossil collecting trip headed by J. Leidy into the same area two years later. Also in 1870, O. C. Marsh discovered and named the Uinta Basin, making a significant fossil vertebrate collection there. Numerous Eocene mammals as well as reptiles and fish were collected in the Basin proper, while a turtle shell and dinosaur teeth were recovered from the upturned Mesozoic beds on the eastern rim of the Uinta Basin. A Jurassic crocodile humerus was found by Marsh along the eastern flank of the Uinta Mountains. In subsequent years before the turn of the century several institutions sent paleontological parties into this area. E. D. Cope in 1880 identified fossil fish and a crocodile from Eocene deposits of central Utah. Pleistocene mammals were first reported by P. A. Chadbourne (1871) and C. King (1878) from Salt Lake and Utah valleys. While early expeditions for vertebrate fossils concentrated largely on adjacent states, many of America's prominent 19th Century vertebrate paleontologists collected fossils in Utah. Their work pioneered the way for present-day paleontologists.

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Goswami, Anjali, Eve Noirault, Ellen J. Coombs, Julien Clavel, Anne-Claire Fabre, Thomas J. D. Halliday, Morgan Churchill, et al. "Attenuated evolution of mammals through the Cenozoic." Science 378, no. 6618 (October 28, 2022): 377–83. http://dx.doi.org/10.1126/science.abm7525.

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The Cenozoic diversification of placental mammals is the archetypal adaptive radiation. Yet, discrepancies between molecular divergence estimates and the fossil record fuel ongoing debate around the timing, tempo, and drivers of this radiation. Analysis of a three-dimensional skull dataset for living and extinct placental mammals demonstrates that evolutionary rates peak early and attenuate quickly. This long-term decline in tempo is punctuated by bursts of innovation that decreased in amplitude over the past 66 million years. Social, precocial, aquatic, and herbivorous species evolve fastest, especially whales, elephants, sirenians, and extinct ungulates. Slow rates in rodents and bats indicate dissociation of taxonomic and morphological diversification. Frustratingly, highly similar ancestral shape estimates for placental mammal superorders suggest that their earliest representatives may continue to elude unequivocal identification.

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Novacek, Michael J. "The Radiation of Placental Mammals." Short Courses in Paleontology 7 (1994): 220–37. http://dx.doi.org/10.1017/s2475263000001331.

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The placental or eutherian mammals comprise about twenty living orders and several extinct ones. The morphological and adaptive range of this group is extraordinary; diversification has produced lineages as varied as humans and their primate relatives, flying bats, swimming whales, ant-eating anteaters, pangolins and aardvarks, a baroque extravagance of horned, antlered, and trunk-nosed herbivores (ungulates), as well as the supremely diverse rats, mice, beavers and porcupines of the order Rodentia. Such adaptive diversity, and the emergence of thousands of living and fossil species, apparently resulted from a radiation beginning in the late Mesozoic between 65 and 80 million years ago (Novacek, 1990). This explosive radiation (Figure 1) is one of the more intriguing chapters of vertebrate history, and the problem has attracted interest from unusually varied perspectives. As a result, eutherian mammals are known from a rapidly growing molecular database, as well as a wealth of morphological characters and a comparatively enriched fossil record. The interplay of molecular and morphological investigation is more apparent in the case of placental mammals that in any other vertebrates, perhaps more than in any other group of organisms.

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Bibi, Faysal, and Wolfgang Kiessling. "Continuous evolutionary change in Plio-Pleistocene mammals of eastern Africa." Proceedings of the National Academy of Sciences 112, no. 34 (August 10, 2015): 10623–28. http://dx.doi.org/10.1073/pnas.1504538112.

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Much debate has revolved around the question of whether the mode of evolutionary and ecological turnover in the fossil record of African mammals was continuous or pulsed, and the degree to which faunal turnover tracked changes in global climate. Here, we assembled and analyzed large specimen databases of the fossil record of eastern African Bovidae (antelopes) and Turkana Basin large mammals. Our results indicate that speciation and extinction proceeded continuously throughout the Pliocene and Pleistocene, as did increases in the relative abundance of arid-adapted bovids, and in bovid body mass. Species durations were similar among clades with different ecological attributes. Occupancy patterns were unimodal, with long and nearly symmetrical origination and extinction phases. A single origination pulse may be present at 2.0–1.75 Ma, but besides this, there is no evidence that evolutionary or ecological changes in the eastern African record tracked rapid, 100,000-y-scale changes in global climate. Rather, eastern African large mammal evolution tracked global or regional climatic trends at long (million year) time scales, while local, basin-scale changes (e.g., tectonic or hydrographic) and biotic interactions ruled at shorter timescales.

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Brinkman, P. D., and S. F. Vizcaíno. "Clemente Onelli's sketch map and his first-hand, retrospective account of an early fossil-hunting expedition along the Río Santa Cruz, southern Patagonia, 1888–1889." Archives of Natural History 41, no. 2 (October 2014): 326–37. http://dx.doi.org/10.3366/anh.2014.0251.

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A 1922 letter from Clemente Onelli to North American paleontologist Elmer S. Riggs, found at Chicago's Field Museum, is one of only a few known first-hand accounts of the former's participation on a fossil hunting expedition along the Río Santa Cruz, southern Patagonia, 1888–1889. Onelli and his companions, who were sent to Patagonia by Francisco P. Moreno, director of the Museo de La Plata, were among the first to collect fossil mammals at this important locality. Moreno had first discovered fossil mammals there in 1876–1877. He then sent Carlos Ameghino, who worked as an assistant preparator of palaeontology at the museum, to revisit his discoveries in January 1887. Ameghino later lost his position at the museum over a dispute between his brother, paleontologist Florentino Ameghino, and the director, in March 1889. Onelli, who had only been associated with the Museo de La Plata for a few short months, was asked by Moreno to accompany a new expedition outfitted in 1888–1889. In December 1922, Riggs travelled to South America to make a representative collection of the fossil mammals of Argentina and Bolivia. Learning of his arrival in Buenos Aires, Onelli wrote him a letter, in Spanish, providing detailed information about fossil localities along the Río Santa Cruz. This letter, translated here, along with the accompanying sketch map, provides previously unknown details about Onelli's itinerary and his observations.

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Sánchez-Villagra, Marcelo R. "Developmental palaeontology in synapsids: the fossil record of ontogeny in mammals and their closest relatives." Proceedings of the Royal Society B: Biological Sciences 277, no. 1685 (January 13, 2010): 1139–47. http://dx.doi.org/10.1098/rspb.2009.2005.

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The study of fossilized ontogenies in mammals is mostly restricted to postnatal and late stages of growth, but nevertheless can deliver great insights into life history and evolutionary mechanisms affecting all aspects of development. Fossils provide evidence of developmental plasticity determined by ecological factors, as when allometric relations are modified in species which invaded a new space with a very different selection regime. This is the case of dwarfing and gigantism evolution in islands. Skeletochronological studies are restricted to the examination of growth marks mostly in the cement and dentine of teeth and can provide absolute age estimates. These, together with dental replacement data considered in a phylogenetic context, provide life-history information such as maturation time and longevity. Palaeohistology and dental replacement data document the more or less gradual but also convergent evolution of mammalian growth features during early synapsid evolution. Adult phenotypes of extinct mammals can inform developmental processes by showing a combination of features or levels of integration unrecorded in living species. Some adult features such as vertebral number, easily recorded in fossils, provide indirect information about somitogenesis and hox-gene expression boundaries. Developmental palaeontology is relevant for the discourse of ecological developmental biology, an area of research where features of growth and variation are fundamental and accessible among fossil mammals.

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Puttick, Mark N., and Gavin H. Thomas. "Fossils and living taxa agree on patterns of body mass evolution: a case study with Afrotheria." Proceedings of the Royal Society B: Biological Sciences 282, no. 1821 (December 22, 2015): 20152023. http://dx.doi.org/10.1098/rspb.2015.2023.

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Most of life is extinct, so incorporating some fossil evidence into analyses of macroevolution is typically seen as necessary to understand the diversification of life and patterns of morphological evolution. Here we test the effects of inclusion of fossils in a study of the body size evolution of afrotherian mammals, a clade that includes the elephants, sea cows and elephant shrews. We find that the inclusion of fossil tips has little impact on analyses of body mass evolution; from a small ancestral size (approx. 100 g), there is a shift in rate and an increase in mass leading to the larger-bodied Paenungulata and Tubulidentata, regardless of whether fossils are included or excluded from analyses. For Afrotheria, the inclusion of fossils and morphological character data affect phylogenetic topology, but these differences have little impact upon patterns of body mass evolution and these body mass evolutionary patterns are consistent with the fossil record. The largest differences between our analyses result from the evolutionary model, not the addition of fossils. For some clades, extant-only analyses may be reliable to reconstruct body mass evolution, but the addition of fossils and careful model selection is likely to increase confidence and accuracy of reconstructed macroevolutionary patterns.

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Vrba, E. S., and D. DeGusta. "Do species populations really start small? New perspectives from the Late Neogene fossil record of African mammals." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 359, no. 1442 (February 29, 2004): 285–93. http://dx.doi.org/10.1098/rstb.2003.1397.

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This analysis of all known African larger mammals of the past 10 Myr offers new perspectives on the geographical circumstances of speciation. Our central question is: does the fossil evidence support the idea that most new species start as small populations and, if true, how long is the average growth interval until species are established at their mean later size? This simple question is important to unravelling the competing claims of rival models of speciation. We approached it by direct use of fossil data, which, to our knowledge, has not been done previously. We compared the numbers of fossil site records, as a proxy for magnitude of geographical spread, between survivorship intervals across all species. The results show that the average mammal species has indeed started its life in a relatively small population, and thereafter increased rapidly in geographical spread to reach its long–term equilibrium abundance by about 1 million years after origin. Some theoretical implications of these results are discussed.

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Journal articles on the topic 'Mammals, Fossil'

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