cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.7211840.v2
title: Reconstruction of the life history traits in the giant salamander <i>Aviturus exsecratus</i> (Caudata, Cryptobranchidae) from the Paleocene of Mongolia using zygapophyseal skeletochronology

description: Here we describe life history traits in the giant cryptobranchid salamander <i>Aviturus exsecratus</i> from the Paleocene of Mongolia using non-destructive approach for skeletochronological analysis based on the counting of cyclical growth rings on articular surfaces of zygapophyseal processes of vertebrae (= zygapophyseal skeletochronology). We found that <i>Aviturus exsecratus</i> had a similar time of the attainment of sexual maturity and decreasing of juvenile growth (5–8 years) and estimated body size at maturity (50–60% of the maximum size) as modern cryptobranchids. Maximum longevity estimated for <i>A. exsecratus</i> is about 25 years. <i>A. exsecratus</i> had a developmental trajectory similar to that of modern cryptobranchids and is not characterized by extended ontogeny. PIN: Paleontological Institute; Russian Academy of Sciences; Moscow; Russia.
DOI: 10.6084/m9.figshare.7206692
title: Pleistocene seabirds from Shiriya, northeast Japan: systematics and oceanographic context

description: Seabirds are higher-order predators in the marine ecosystem and hence good indicators of the marine environment. Although the North Pacific has been the focal area for investigations of seabird faunal dynamics, the Pleistocene seabird fossil record has been scarce in the western North Pacific. Here, remains of 32 species of seabirds and related taxa (Anatidae, Podicipedidae, Gaviidae, Diomedeidae, Hydrobatidae, Procellariidae, Phalacrocoracidae, Scolopacidae, Laridae, and Alcidae) are reported from the middle–late Pleistocene Shiriya local fauna, northeastern Japan (Marine Isotope Stages 9 and 5e, ~ 320 and ~ 120 ka). This is the first substantial Pleistocene seabird fauna reported from the region so far, and includes globally first fossil records for <i>Cepphus carbo</i> and extant species of <i>Aethia</i>. The fauna also includes three extinct species, <i>Shiriyanetta hasegawai, Mancalla</i>? sp., and <i>Uria onoi</i>, the former two of which were flightless. The occurrence of immature individuals indicates that at least two species had nearby breeding sites. The seabird populations had probably been sustained by enhanced oceanic productivity in this area during their age, but oceanographic fluctuations in the subsequent glacial period, including the probable disappearance of a nearby oceanic front, would have seriously affected their subsistence, likely causing local extinctions of some species.
DOI: 10.6084/m9.figshare.7206692.v1
title: Pleistocene seabirds from Shiriya, northeast Japan: systematics and oceanographic context

description: Seabirds are higher-order predators in the marine ecosystem and hence good indicators of the marine environment. Although the North Pacific has been the focal area for investigations of seabird faunal dynamics, the Pleistocene seabird fossil record has been scarce in the western North Pacific. Here, remains of 32 species of seabirds and related taxa (Anatidae, Podicipedidae, Gaviidae, Diomedeidae, Hydrobatidae, Procellariidae, Phalacrocoracidae, Scolopacidae, Laridae, and Alcidae) are reported from the middle–late Pleistocene Shiriya local fauna, northeastern Japan (Marine Isotope Stages 9 and 5e, ~ 320 and ~ 120 ka). This is the first substantial Pleistocene seabird fauna reported from the region so far, and includes globally first fossil records for <i>Cepphus carbo</i> and extant species of <i>Aethia</i>. The fauna also includes three extinct species, <i>Shiriyanetta hasegawai, Mancalla</i>? sp., and <i>Uria onoi</i>, the former two of which were flightless. The occurrence of immature individuals indicates that at least two species had nearby breeding sites. The seabird populations had probably been sustained by enhanced oceanic productivity in this area during their age, but oceanographic fluctuations in the subsequent glacial period, including the probable disappearance of a nearby oceanic front, would have seriously affected their subsistence, likely causing local extinctions of some species.
DOI: 10.6084/m9.figshare.7211840
title: Reconstruction of the life history traits in the giant salamander <i>Aviturus exsecratus</i> (Caudata, Cryptobranchidae) from the Paleocene of Mongolia using zygapophyseal skeletochronology

description: Here we describe life history traits in the giant cryptobranchid salamander <i>Aviturus exsecratus</i> from the Paleocene of Mongolia using non-destructive approach for skeletochronological analysis based on the counting of cyclical growth rings on articular surfaces of zygapophyseal processes of vertebrae (= zygapophyseal skeletochronology). We found that <i>Aviturus exsecratus</i> had a similar time of the attainment of sexual maturity and decreasing of juvenile growth (5–8 years) and estimated body size at maturity (50–60% of the maximum size) as modern cryptobranchids. Maximum longevity estimated for <i>A. exsecratus</i> is about 25 years. <i>A. exsecratus</i> had a developmental trajectory similar to that of modern cryptobranchids and is not characterized by extended ontogeny. PIN: Paleontological Institute; Russian Academy of Sciences; Moscow; Russia.
DOI: 10.6084/m9.figshare.7211840.v1
title: Reconstruction of the life history traits in the giant salamander <i>Aviturus exsecratus</i> (Caudata, Cryptobranchidae) from the Paleocene of Mongolia using zygapophyseal skeletochronology

description: Here we describe life history traits in the giant cryptobranchid salamander <i>Aviturus exsecratus</i> from the Paleocene of Mongolia using non-destructive approach for skeletochronological analysis based on the counting of cyclical growth rings on articular surfaces of zygapophyseal processes of vertebrae (= zygapophyseal skeletochronology). We found that <i>Aviturus exsecratus</i> had a similar time of the attainment of sexual maturity and decreasing of juvenile growth (5–8 years) and estimated body size at maturity (50–60% of the maximum size) as modern cryptobranchids. Maximum longevity estimated for <i>A. exsecratus</i> is about 25 years. <i>A. exsecratus</i> had a developmental trajectory similar to that of modern cryptobranchids and is not characterized by extended ontogeny. <b>Abbreviation:</b> PIN: Paleontological Institute; Russian Academy of Sciences; Moscow; Russia.
DOI: 10.6084/m9.figshare.7301915
title: Enigmatic encrusting fossils from the Upper Devonian of Russia: probable <i>Rothpletzella</i> microproblematica preserved in three dimensions

description: Intriguing microfossils encrusting certain Upper Devonian brachiopod shells from the Central Devonian Field, Russia, are reported for the first time. The fossils are pyritized, have fan-shaped morphologies and are formed by tightly-packed branches which divide dichotomously at different points in their development. The organisms preserved grew horizontally on shelly substrates. Comparisons with similar fossils known from the literature indicate that they do not represent any animal taxon commonly encrusting hard substrates. Instead, the morphology, organization and growth mode of these fossils are most similar to microfossils known under the name <i>Rothpletzella</i>, which so far have only been known from thin sections. <i>Rothpletzella</i> is a problematicum for which algal affinities have been proposed. The preserved branches of the fossils described here are too large for cyanobacterial cells. Their large size suggests their placement, along with other described <i>Rothpletzella</i> fossils, within the green algae order Bryopsidales. It is suggested that originally, these organisms possessed thalli encased within a thin, delicate calcified sheath. After burial the thalli underwent pyritization via sulphate reduction mediated by bacterial activity within low pH, dysoxic microenvironment, and their sheath dissolved. As three-dimensionally preserved, these algae provide a new, previously unrecognized, component within the Devonian encrusting communities.
DOI: 10.6084/m9.figshare.7301915.v1
title: Enigmatic encrusting fossils from the Upper Devonian of Russia: probable <i>Rothpletzella</i> microproblematica preserved in three dimensions

description: Intriguing microfossils encrusting certain Upper Devonian brachiopod shells from the Central Devonian Field, Russia, are reported for the first time. The fossils are pyritized, have fan-shaped morphologies and are formed by tightly-packed branches which divide dichotomously at different points in their development. The organisms preserved grew horizontally on shelly substrates. Comparisons with similar fossils known from the literature indicate that they do not represent any animal taxon commonly encrusting hard substrates. Instead, the morphology, organization and growth mode of these fossils are most similar to microfossils known under the name <i>Rothpletzella</i>, which so far have only been known from thin sections. <i>Rothpletzella</i> is a problematicum for which algal affinities have been proposed. The preserved branches of the fossils described here are too large for cyanobacterial cells. Their large size suggests their placement, along with other described <i>Rothpletzella</i> fossils, within the green algae order Bryopsidales. It is suggested that originally, these organisms possessed thalli encased within a thin, delicate calcified sheath. After burial the thalli underwent pyritization via sulphate reduction mediated by bacterial activity within low pH, dysoxic microenvironment, and their sheath dissolved. As three-dimensionally preserved, these algae provide a new, previously unrecognized, component within the Devonian encrusting communities.
DOI: 10.6084/m9.figshare.7945445
title: Ontogeny and variation of a protoceratopsid dinosaur <i>Bagaceratops rozhdestvenskyi</i> from the Late Cretaceous of the Gobi Desert

description: <i>Bagaceratops rozhdestvenskyi</i> is a ceratopsian dinosaur from the Late Cretaceous Baruungoyot Formation of the Gobi Desert, closely related to <i>Protoceratops</i> spp. Several <i>Bag. rozhdestvenskyi</i> skulls demonstrate a wide range of variation in their morphology and size. Here I argue that the observed variability is most likely of intraspecific nature. Specimens classified in a few allegedly distinct species from the same or near-contemporary sediments, namely <i>Gobiceratops minutus</i>, <i>Lamaceratops tereschenkoi</i> and <i>Platyceratops tatarinovi</i> from Baruungoyot Formation, and <i>Magnirostris dodsoni</i> from Bayan Mandahu, are younger subjective synonyms of <i>Bag. rozhdestvenskyi</i>. They plausibly represent an ontogenetic series within the latter. <i>Breviceratops kozlowskii</i>is a distinct taxon. The evolutionary relationships within Protoceratopsidae are complicated by the mosaic distribution of plesiomorphic and derived features in distinct species. I suggest that taxa distribution and observed changes in morphology are an evidence for the ancestral position of <i>Protoceratops andrewsi</i> among protoceratopsids. It implies possible temporary separation between the geological formations of the Gobi Desert yielding distinct protoceratopsid species. The novel evolutionary scenario suggests number of convergences that occurred in Protoceratopsidae and Ceratopsoidea (reduction of the premaxillary dentition, fusion of nasals, development of the accessory antorbital fenestra). Present study reveals the significance of the intraspecific and ontogenetic variation in the study of the neoceratopsian taxonomy.
DOI: 10.6084/m9.figshare.7945445.v1
title: Ontogeny and variation of a protoceratopsid dinosaur <i>Bagaceratops rozhdestvenskyi</i> from the Late Cretaceous of the Gobi Desert

description: <i>Bagaceratops rozhdestvenskyi</i> is a ceratopsian dinosaur from the Late Cretaceous Baruungoyot Formation of the Gobi Desert, closely related to <i>Protoceratops</i> spp. Several <i>Bag. rozhdestvenskyi</i> skulls demonstrate a wide range of variation in their morphology and size. Here I argue that the observed variability is most likely of intraspecific nature. Specimens classified in a few allegedly distinct species from the same or near-contemporary sediments, namely <i>Gobiceratops minutus</i>, <i>Lamaceratops tereschenkoi</i> and <i>Platyceratops tatarinovi</i> from Baruungoyot Formation, and <i>Magnirostris dodsoni</i> from Bayan Mandahu, are younger subjective synonyms of <i>Bag. rozhdestvenskyi</i>. They plausibly represent an ontogenetic series within the latter. <i>Breviceratops kozlowskii</i>is a distinct taxon. The evolutionary relationships within Protoceratopsidae are complicated by the mosaic distribution of plesiomorphic and derived features in distinct species. I suggest that taxa distribution and observed changes in morphology are an evidence for the ancestral position of <i>Protoceratops andrewsi</i> among protoceratopsids. It implies possible temporary separation between the geological formations of the Gobi Desert yielding distinct protoceratopsid species. The novel evolutionary scenario suggests number of convergences that occurred in Protoceratopsidae and Ceratopsoidea (reduction of the premaxillary dentition, fusion of nasals, development of the accessory antorbital fenestra). Present study reveals the significance of the intraspecific and ontogenetic variation in the study of the neoceratopsian taxonomy.
DOI: 10.6084/m9.figshare.8025140
title: Taxonomic revision of a Machairodontinae (Felidae) from the Late Hemphillian of México

description: In the Late Hemphillian of Guanajuato, México, fossil material assigned to <i>Machairodus</i> sp. cf. <i>M. coloradensis</i> (= <i>Amphimachairodus coloradensis</i>) was described in the 90´s. A detailed morphological reexamination of this material and its comparison to other felid genera raises doubts about its original taxonomic assignment. The presence of hypertrophied upper canine and almost all teeth with strong serration, confirms its identification as a Scimitar-tooth felid, but it is smaller than <i>A. coloradensis</i>. Because of the unique combination of synapomorphies present in this specimen, where a more developed flange stands out than another known <i>Amphimachairodus</i>, we propose that it represents a new taxon of felid and name a new species: <i>A. alvarezi</i> sp. nov. This new taxon adds information to the understanding of the diversity of machairodonts during the Miocene-Pleistocene times in North America. urn:lsid:zoobank.org:pub:00EB02F7-8ED4-4006-904E-A6C20A8E9993
DOI: 10.6084/m9.figshare.8025140.v1
title: Taxonomic revision of a Machairodontinae (Felidae) from the Late Hemphillian of México

description: In the Late Hemphillian of Guanajuato, México, fossil material assigned to <i>Machairodus</i> sp. cf. <i>M. coloradensis</i> (= <i>Amphimachairodus coloradensis</i>) was described in the 90´s. A detailed morphological reexamination of this material and its comparison to other felid genera raises doubts about its original taxonomic assignment. The presence of hypertrophied upper canine and almost all teeth with strong serration, confirms its identification as a Scimitar-tooth felid, but it is smaller than <i>A. coloradensis</i>. Because of the unique combination of synapomorphies present in this specimen, where a more developed flange stands out than another known <i>Amphimachairodus</i>, we propose that it represents a new taxon of felid and name a new species: <i>A. alvarezi</i> sp. nov. This new taxon adds information to the understanding of the diversity of machairodonts during the Miocene-Pleistocene times in North America. urn:lsid:zoobank.org:pub:00EB02F7-8ED4-4006-904E-A6C20A8E9993
DOI: 10.6084/m9.figshare.7862213
title: Dental variability and distinguishability in <i>Mosasaurus lemonnieri</i> (Mosasauridae) from the Campanian and Maastrichtian of Belgium, and implications for taxonomic assessments of mosasaurid dentitions

description: <i>Mosasaurus lemonnieri</i> is a mosasaurine mosasaurid first unearthed from the lower Maastrichtian of the Mons Basin, southern Belgium. Even though numerous well-preserved specimens have been attributed to the taxon, the knowledge of its anatomy is surprisingly poor and merely limited to some general characteristics. Here I describe the morphology of the marginal dentition of <i>M. lemonnieri</i> based on the holotype and 14 referred individuals originating from the upper Campanian and Maastrichtian of Belgium. The dental variability is assessed through linear discriminant analyses aimed to appraise the tooth crown distinguishability between (1) individuals, (2) tooth-bearing elements (premaxillae, maxillae, and dentaries), and (3) within particular jaw regions (anterior, middle, and posterior). The overall dental distinguishability between individuals was, expectedly, poor though the rates of correctly classified teeth differed for particular specimens, which can have taxonomic implications. The premaxillary and maxillary teeth were inferred to be more distinguishable than the dentary teeth. The dental distinguishability of <i>M. lemonnieri</i> is further compared to that of other sympatric and potentially sympatric taxa. The use of mosasaurid dental measurements substantially facilitates the comparisons of mosasaurid teeth on both inter- and intraspecific scale, increasing the accuracy of the studies appraising the patterns of mosasaurid dental evolution.
DOI: 10.6084/m9.figshare.7862213.v1
title: Dental variability and distinguishability in <i>Mosasaurus lemonnieri</i> (Mosasauridae) from the Campanian and Maastrichtian of Belgium, and implications for taxonomic assessments of mosasaurid dentitions

description: <i>Mosasaurus lemonnieri</i> is a mosasaurine mosasaurid first unearthed from the lower Maastrichtian of the Mons Basin, southern Belgium. Even though numerous well-preserved specimens have been attributed to the taxon, the knowledge of its anatomy is surprisingly poor and merely limited to some general characteristics. Here I describe the morphology of the marginal dentition of <i>M. lemonnieri</i> based on the holotype and 14 referred individuals originating from the upper Campanian and Maastrichtian of Belgium. The dental variability is assessed through linear discriminant analyses aimed to appraise the tooth crown distinguishability between (1) individuals, (2) tooth-bearing elements (premaxillae, maxillae, and dentaries), and (3) within particular jaw regions (anterior, middle, and posterior). The overall dental distinguishability between individuals was, expectedly, poor though the rates of correctly classified teeth differed for particular specimens, which can have taxonomic implications. The premaxillary and maxillary teeth were inferred to be more distinguishable than the dentary teeth. The dental distinguishability of <i>M. lemonnieri</i> is further compared to that of other sympatric and potentially sympatric taxa. The use of mosasaurid dental measurements substantially facilitates the comparisons of mosasaurid teeth on both inter- and intraspecific scale, increasing the accuracy of the studies appraising the patterns of mosasaurid dental evolution.
DOI: 10.6084/m9.figshare.7380596
title: A new Abelisauridae (Dinosauria: Theropoda) from São José do Rio Preto Formation, Upper Cretaceous of Brazil and comments on the Bauru Group fauna

description: Abelisaurid theropods are well-know from the Cretaceous of several parts of the Southern Hemisphere, including South America, Madagascar, and Africa, but also in India and Europe. Abelisaurids are high-diverse among other theropods with several cervicocephalic specializations reaching medium/large sizes. In the present contribution, we describe a new abelisaurid (<i>Thanos simonattoi</i>, gen. et sp. nov.) from the São José do Rio Preto Formation, Bauru Group, Brazil (Upper Cretaceous). <i>Thanos</i> differs from other theropods by having a well-developed keel becoming wider and deeper posteriorly on the ventral surface; two lateral small foramina separated by a relative wide wall on each lateral surface of the centrum, and well-developed and deep prezygapophyseal spinodiapophyseal fossae. The closed sutures between the axis and odontoid suggest that <i>Thanos</i> had reached a subadult/adult stage before death. <i>Thanos</i> is phylogenetically related to Brachyrostra abelisaurid. The keel on the ventral axial centrum in abelisauroids is here interpreted as a homoplastic condition that became more pronounced towards the phylogeny. The presence of well-developed keel in <i>Thanos</i> suggests that this taxon could be more derived than other abelisaurids. Finally, even though abelisaurids could reach large sizes, <i>Thanos</i> shared the environment with a larger theropod that was probably close to Megaraptora.
DOI: 10.6084/m9.figshare.7380596.v1
title: A new Abelisauridae (Dinosauria: Theropoda) from São José do Rio Preto Formation, Upper Cretaceous of Brazil and comments on the Bauru Group fauna

description: Abelisaurid theropods are well-know from the Cretaceous of several parts of the Southern Hemisphere, including South America, Madagascar, and Africa, but also in India and Europe. Abelisaurids are high-diverse among other theropods with several cervicocephalic specializations reaching medium/large sizes. In the present contribution, we describe a new abelisaurid (<i>Thanos simonattoi</i>, gen. et sp. nov.) from the São José do Rio Preto Formation, Bauru Group, Brazil (Upper Cretaceous). <i>Thanos</i> differs from other theropods by having a well-developed keel becoming wider and deeper posteriorly on the ventral surface; two lateral small foramina separated by a relative wide wall on each lateral surface of the centrum, and well-developed and deep prezygapophyseal spinodiapophyseal fossae. The closed sutures between the axis and odontoid suggest that <i>Thanos</i> had reached a subadult/adult stage before death. <i>Thanos</i> is phylogenetically related to Brachyrostra abelisaurid. The keel on the ventral axial centrum in abelisauroids is here interpreted as a homoplastic condition that became more pronounced towards the phylogeny. The presence of well-developed keel in <i>Thanos</i> suggests that this taxon could be more derived than other abelisaurids. Finally, even though abelisaurids could reach large sizes, <i>Thanos</i> shared the environment with a larger theropod that was probably close to Megaraptora.
DOI: 10.6084/m9.figshare.7491881
title: Every cloud has a silver lining: X-ray micro-CT reveals <i>Orsunius</i> rove beetle in Rovno amber from a specimen inaccessible to light microscopy

description: The exceptionally well-preserved and diverse insect fossil record of the Baltic amber group is a unique source for science. However, bubbles and thick layers of white gaseous froth cover numerous inclusions in this type of amber, rendering their examination with traditional light microscopy impossible. Here, we show that X-ray micro-computed tomography can be an efficient tool in such cases. We scanned a completely covered rove beetle (Staphylinidae) fossil in a piece of the relatively recently discovered Rovno amber. The resulting reconstruction was detailed enough to identify the fossil as the first extinct species of <i>Orsunius</i> Assing, an extant genus from the systematically very challenging subtribe Medonina (Lathrobiini, Paederinae). We summarize all previous studies on the origin of gaseous inclusions around fossil specimens in Baltic amber and discuss the technical challenges of using µ-CT where a mostly hollow specimen is surrounded by bubbles of the same density. Since recent <i>Orsunius</i> exclusively occur in the Oriental biogeographic region, we discuss the possible climate change driven speciation scenarios between <i>Orsunius electronefelus</i> sp. nov. and the former. urn:lsid:zoobank.org:pub:8ECD641E-629F-46DC-BC81-217C529ACA84