Fragmentary Specimens Research Articles

Overview on the tetrapods from Faixa Nova-Cerrito I site (Hyperodapedon Assemblage Zone), Upper Triassic of southernmost Brazil

ABSTRACT The Faixa Nova-Cerrito I site, in the municipality of Santa Maria, Rio Grande do Sul, Brazil, displays rock layers from the Hyperodapedon Assemblage Zone (AZ), Carnian age of 233.23 ± 0.73 Ma (based on data collected in the nearby and correlated ‘Alemoa’ area), Santa Maria Supersequence, Upper Triassic, Paraná Basin. The new postcranial remains studied are referred to as Dinosauriformes indet., Silesauridae indet., Gnathovorax cabreirai (Herrerasauridae), and a Chiniquodontidae cynodont, all collected between 1996 and 2002, during the Pro-Guaíba project. The identification of specific groups like silesaurids, herrerasaurids and chiniquodontids for the first time in this outcrop adds valuable nuances to the biostratigraphical framework of the Brazilian Upper Triassic record. These findings straighten the correlation of the basal layers of Faixa Nova-Cerrito I Site with other Hyperodapedon Acme Subzone outcrops and provide some insights on the diversity of the upper Teyumbaita-layers. Our result in part corroborates the current hypothesis for the subdivision of the Hyperodapedon AZ, but the probable silesaur occurrence within the Teyumbaita-layers does not yet indicate that those levels are equivalent to those from the Exaeretodon Subzone. Our results highlight the importance of even fragmentary specimens in biostratigraphy and diversity estimations.

A re-evaluation of Scelidosaurus remains from Ireland and the importance of apomorphy-based identifications

Scelidosaurus is a herbivorous dinosaur belonging to the ornithischian clade Thyreophora. Until recently, its distribution was limited to the cliffs of Charmouth, on the south coast of Dorset, United Kingdom. In 2021, a fragmentary specimen from Lower Jurassic strata in Northern Ireland (BELUM K3998) was referred tentatively to Scelidosaurus. This bone, the proximal end of a femur, was suggested to be an ornithischian based on several characteristics, including gross morphology and osteohistology. This study reassesses these characteristics, and finds no evidence to support their use for identifying this specimen as either an ornithischian or Scelidosaurus. With the most comprehensive studies on Scelidosaurus finding no autapomorphies of the proximal femur, this study regards BELUM K3998 as Dinosauria indet. Additionally, this study highlights the importance of apomorphy-based approaches in taxonomy and the benefits of such methodologies.

New xenophyophores (Foraminifera, Monothalamea) from the eastern Clarion-Clipperton Zone (equatorial Pacific).

Xenophyophores are large, agglutinated foraminifera that dominate the benthic megafauna in some parts of the deep sea. Here, we describe an assemblage of largely fragmentary specimens from the Clarion-Clipperton Zone (CCZ), an area of the eastern abyssal Pacific hosting large, commercially significant deposits of polymetallic nodules. We recognised 18 morphospecies of which eight yielded DNA sequences. These include two new genera and three new species, Claraclippia seminuda gen. & sp. nov., Stereodiktyoma mollis gen. & sp. nov., and Aschemonella tani sp. nov., three that are assigned to known species, Abyssalia foliformis, Aschemonella monilis and Shinkaiya contorta, and two assigned to open nomenclature forms Abyssalia aff. foliformis and Stannophyllum aff. granularium. An additional ten forms are represented only by morphology. The following seven are placed in known genera, species and open-nomenclature forms: Aschemonella? sp., Homogammina sp., Psammina multiloculata, P. aff. multiloculata, P. aff. limbata form 1 sensu Gooday et al., 2018, P. aff. limbata form 2 sensu Gooday et al., 2018, and Stannophyllum spp. The other three could not be identified to genus level. This new collection brings the total of described and undescribed species and morphotypes from the CCZ to 27 and 70, respectively, reinforcing the already high diversity of xenophyophores known from this part of the Pacific.

The official presentation to science of a new species of Hechtia (Bromeliaceae: Hechtioideae) from the Pacific Lowlands in Mexico

Background: Hechtia is characterized by its terrestrial, succulent rosettes, dioecy, and unisexual, dimorphic flowers, mainly fragrant. The paucity and fragmentary herbarium material limit the species recognition but living material reveals diagnostic characters to delimitate them.
 Hypothesis: Hechtia species are circumscribed by a combination of vegetative and floral characters of both sexes. If the new taxon does not share morphological characters with other species, it will be described as new.
 Taxon: Hechtia.
 Study site and dates: Chamela-Cuixmala Biosphere Reserve, Jalisco, 1985-2023.
 Methods: Field collected, cultivated as well as herbarium material of the new taxon were analyzed and compared to other species from the Pacific Lowlands and adjacent areas, particularly flowers of both sexes, fruits, and seeds. Conservation status using IUCN criteria is reported for the new species.
 Results: Specimens of Hechtia chamelensis have been misidentified as H. laevis and H. reticulata (both described from fruiting, fragmentary specimens) but the fruit and seed features of both taxa do not match those of the new species. H. chamelensis is known from the Chamela-Cuixmala Biosphere Reserve and it is characterized by strict sympodial growth pattern, green leaves with red hues, shiny and glabrous above, white lepidote below, panicles usually simple to (rarely staminate ones) 2-divided, staminate flowers pinkish to pale white, pistillate with pale green to white petals.
 Conclusions: Vegetative and reproductive features as well as geographical distribution allow the recognition of H. chamelensis as a new species native from Jalisco, Mexico.

Cranial osteology and paleoneurology of Tarjadia ruthae: An erpetosuchid pseudosuchian from the Triassic Chañares Formation (late Ladinian-?early Carnian) of Argentina.

Tarjadia ruthae is a quadrupedal terrestrial pseudosuchian from the Middle-early Upper Triassic of the Chañares Formation, La Rioja Province, Argentina. Originally, this species was identified as an indeterminate archosaur and later as a doswelliid archosauriform based on very fragmentary specimens characterized by the ornamentation of the skull roof and osteoderms. Additional specimens (including skulls and postcrania) recovered in the last decade show that Tarjadia is an erpetosuchid, an enigmatic pseudosuchian group composed of six species registered in Middle-Upper Triassic continental units of Tanzania, Germany, Scotland, North America, Brazil, and Argentina. Tarjadia ruthae from Argentina and Parringtonia gracilis from Tanzania are the best preserved and more abundant species. Although the monophyly of Erpetosuchidae is well supported, alternative high-level positions within Archosauria have been suggested, such as sister taxon to Crocodylomorpha, Aetosauria, or Ornithosuchidae. In order to improve the knowledge about the erpetosuchids, we performed a detailed description and paleoneurological reconstruction of the skull of Tarjadia ruthae, based on two articulated partial skulls (CRILAR-Pv 478 and CRILAR-Pv 495) and other fragmentary specimens. We analyzed the stratigraphic and geographic occurrence of historical and new specimens of Tarjadia and provided a new emended diagnosis (the same for the genus as for the species, due to monotypy) along with a comparative description of the cranial endocast. The skull of Tarjadia is robust, with a thick and strongly ornamented skull roof, triangular in dorsal view, with concave lateral margins at mid-length that form an abrupt widened posterior region. The external nares are the smallest openings of the skull. The antorbital fossa is deeply excavated and has a small heart-shaped fenestra with both lobes pointing anteriorly. The supratemporal fenestrae are as large and rounded as the orbits, and the infratemporal fenestrae are L-shaped with an extensive excavation along the jugal, quadratojugal and quadrate. The hemimandibles are low, slightly concave on the dentigerous region and strongly convex on the posterior region, conferring them a S-shaped profile in dorsal view. The external mandibular fenestra is small and elliptic, being twice longer than high. The maxillary dentition is restricted to the anterior to mid region of the rostrum. Since the braincase of both specimens is partially damaged, the dorsal surface of the brain could not be entirely reconstructed. As a result, the endocast is anteroposteriorly elongated and seemingly flat, and the cephalic flexure seems to be lower than expected for a suchian. The labyrinth is twice wider than high, the semicircular canals are remarkably straight, and the anterior canal is longer than the posterior one.

Docodontans from the Lower Cretaceous of Yakutia, Russia: New insights into diversity, morphology, and phylogeny of Docodonta

Docodonta are the most abundant and taxonomically diverse group of mammaliaforms in the high paleolatitude Lower Cretaceous Teete locality in Yakutia, Russia. Docodontans are represented by the tegotheriids Khorotherium yakutense and Ergetiis ichchi gen. et sp. nov., and possibly two more taxa known from fragmentary specimens (Docodonta indet.). Ergetiis ichchi gen. et sp. nov. shows a reduction and posterior shift of the angular process of the dentary which could indicate a reduction of the mandibular middle ear potentially in a way analogous to the transitional mammalian middle ear of Eutriconodonta. A revised phylogenetic analysis of Docodonta suggests a stemward position of Docodontidae and a sister group relationship for Simpsonodontidae and Tegotheriidae.

A saurischian (Archosauria, Dinosauria) ilium from the Upper Triassic of southern Brazil and the rise of Herrerasauria.

The Carnian (Upper Triassic) rocks of the Candelária Sequence present a rich record of dinosaurs, including some of the oldest known dinosaurs worldwide. In this contribution we describe the first unequivocal dinosaur from the Pivetta site, located in the Restinga Sêca municipality, Southern Brazil. The specimen CAPPA/UFSM 0373 is an isolated but well-preserved left ilium. A thorough examination of the specimen's anatomy and a phylogenetic analysis provides evidence that CAPPA/UFSM 0373 belongs to the Herrerasauria. We were able to identify several similarities with potential non-herrerasaurid herrerasaurians (e.g., Tawa hallae, "Caseosaurus crosbyensis"), which were previously only known from North American deposits. In contrast, herrerasaurids (e.g., Herrerasaurus ischigualastensis) are almost exclusively known from South America. Our results support the nesting of CAPPA/UFSM 0373 as an early-diverging herrerasaurian. Furthermore, this is potentially the first record of a non-herrerasaurid herrerasaurian in unambiguous Carnian beds, suggesting a hidden diversity of dinosaurs in the Carnian rocks of the Candelária Sequence, which can be revealed even by fragmentary specimens.

A new Liassophlebiidae (Odonata: Heterophlebioidea) from strata close to the Triassic-Jurassic boundary in Somerset, UK

ABSTRACT Liassophlebiidae is an extinct family of damsel-dragonflies found in Upper Triassic and Lower Jurassic strata of Europe, Asia and Antarctica. Whilst Liassophlebiidae is well represented by Lower Jurassic fossils, their lowest occurrence in the Upper Triassic has hitherto only been suggested by three fragmentary specimens. These were originally ascribed to two species: Liassophlebia withersi and Liassophlebia batheri, but the latter is now considered nomen dubium. Here we describe a fourth, better preserved specimen that is likely to be Rhaetian (Late Triassic) in age. The specimen, BRSMG Cg3101 a+b, was collected from Bowdens Quarry, Somerset, UK, from the lower part of the White Lias Formation. The specimen comprises an incomplete forewing attributed to Liassophlebia due to: the small number of antenodals, antesubnodals and crossveins between RP and MA based RP3/4 in the base of RP2 opposite the subnodus; a straight and elongate secondary longitudinal vein in the postdiscoidal area; numerous cells and secondary veins in radial and median areas. The specimen is likely to represent a new species and provides stronger evidence than the previous three specimens of the presence of Liassophlebiidae during the late Rhaetian. Its stratigraphical position suggests that Liassophlebiidae arose in the immediate aftermath of the Triassic-Jurassic mass extinction.

Cranial osteology of the Brazilian dinocephalian Pampaphoneus biccai (Anteosauridae: Syodontinae)

Abstract The Anteosauridae (Dinocephalia) were the largest predators of Guadalupian (Middle Permian) land communities. The, thus far, only known South American anteosaurid is the medium-sized syodontine Pampaphoneus biccai. This taxon was, until now, known only by its holotype, recovered from an outcrop of the Rio do Rasto Formation, Southern Brazil. Here we describe in detail an almost complete Pampaphoneus biccai skull associated with a few postcranial remains (UNIPAMPA 759) recently recovered from the type locality. The novel morphological information provided by this novel, better-preserved, specimen revealed that most characters previously proposed to distinguish Pampaphoneus biccai from Syodon biarmicum are probably ontogenetically constrained. We identify, however, new features that clearly distinguish these two taxa, and provide an updated diagnosis for Pampaphoneus biccai. Our phylogenetic reassessment of the taxon echoes previous propositions in which Pampaphoneus biccai was recovered as an early-divergent Syodontinae. Additionally, we tentatively indicate that a larger fragmentary specimen (UFRGS-PV-0249-P) may represent the mature size of the species, with the similar-sized holotype and UNIPAMPA 759 probably representing subadult individuals.

New theropod dinosaur from the Lower Cretaceous of Japan provides critical implications for the early evolution of ornithomimosaurs

Ornithomimosauria consists of the ostrich-mimic dinosaurs, most of which showing cursorial adaptations, that often exhibit features indicative of herbivory. Recent discoveries have greatly improved our knowledge of their evolutionary history, including the divergence into Ornithomimidae and Deinocheiridae in the Early Cretaceous, but the early part of their history remains obscured because their fossil remains are scarce in the Aptian–Albian sediments. In recent years, many isolated ornithomimosaur remains have been recovered from the Aptian Kitadani Formation of Fukui, central Japan. These remains represent multiple individuals that share some morphological features common to them but unknown in other ornithomimosaurs, suggesting a monospecific accumulation of a new taxon. As a result of the description and phylogenetic analysis, the Kitadani ornithomimosaur is recovered as a new genus and species Tyrannomimus fukuiensis, the earliest definitive deinocheirid that complements our knowledge to understand the early evolutionary history of Ornithomimosauria. Due to its osteological similarity to Tyrannomimus, a taxon previously considered an early tyrannosauroid based on fragmentary specimens, namely Aviatyrannis jurassica, may represent the earliest ornithomimosaur from the Upper Jurassic of Europe, significantly expanding the temporal and biogeographic range of Ornithomimosauria. This finding fills a 20-million-year ghost lineage of Ornithomimosauria implied by the presence of the oldest fossil record of Maniraptora from the Middle Jurassic and is consistent with the hypothesis that their biogeographic range was widespread before the Pangaean breakup in the Kimmeridgian.

The identity of the Silurian retiolitine genera Paraplectograptus and Sagenograptoides (Graptoloidea, Retiolitinae)

The genus Paraplectograptus includes a small number of retiolitine species with an identical development of the main thecal and ancora sleeve lists. A complete virgella-virga-nema development with connecting lists is formed on the obverse side of the tubarium, while the only thecal lists on the reverse side are the lateral apertural lists, connected through the pleural lists of the ancora sleeve. Obverse and reverse sides of the tubarium are connected by the thecal lips on the ventral sides. The characteristic zigzag thecal lists of the reverse side of many early retiolitines are not present in the genus. The development and extent of the reticular ancora sleeve lists on the obverse and reverse sides of the tubarium are quite variable and range from lacking entirely to dense. The genus Pseudoplectograptus is regarded as a junior synonym of Paraplectograptus. Pseudoplectograptus sagenus is transferred to the genus Sagenograptoides. Its type species ‘Sagenograptoides arctos’ was known only from small, immature or fragmentary specimens of the associated Sagenograptoides sagenus. This species bears a characteristic reticulum on the ventral thecal walls, not found in the genus Paraplectograptus, but which is present in other Cyrtograptus lundgreni Biozone retiolitines.

The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones

Early Cretaceous (late Barremian – early Aptian) fissure fill deposits near Balve, North Rhine Westphalia, Germany, have yielded a rich continental vertebrate fauna over the course of the last two decades. More than 250 fragmentary specimens, including more than 150 osteoderms (i.e., granicones), represent the late Early Cretaceous helochelydrid Helochelydra nopcsai, which had previously been reported from the UK, France, and Spain. The new material mostly differs from that from the type section by exhibiting a reduced to absent entoplastral scute and by displaying distinct cranial scute sulci, both of which are interpreted as intraspecific variation. Although morphological insights are limited, the new material reveals that the visceral cavity extends anteriorly and posteriorly to the bridge, a relatively novel feature previously reported for an eclectic mix of compsemydids, pleurosternids, and other helochelydrids. The available sample of granicones reveals great shape diversity, but a morphometric analysis concludes that no distinct morphotypes exist.

Making meaning from fragmentary fossils: Early Homo in the Early to early Middle Pleistocene

In celebration of the 50th anniversary of the Journal of Human Evolution, we re-evaluate the fossil record for early Homo (principally Homo erectus, Homo habilis, and Homo rudolfensis) from early diversification and dispersal in the Early Pleistocene to the ultimate demise of H. erectus in the early Middle Pleistocene. The mid-1990s marked an important historical turning point in our understanding of early Homo with the redating of key H. erectus localities, the discovery of small H. erectus in Asia, and the recovery of an even earlier presence of early Homo in Africa. As such, we compare our understanding of early Homo before and after this time and discuss how the order of fossil discovery and a focus on anchor specimens has shaped, and in many ways biased, our interpretations of early Homo species and the fossils allocated to them. Fragmentary specimens may counter conventional wisdom but are often overlooked in broad narratives. We recognize at least three different cranial and two or three pelvic morphotypes of early Homo. Just one postcranial morph aligns with any certainty to a cranial species, highlighting the importance of explicitly identifying how we link specimens together and to species; we offer two ways of visualizing these connections. Chronologically and morphologically H. erectus is a member of early Homo, not a temporally more recent species necessarily evolved from either H. habilis or H. rudolfensis. Nonetheless, an ancestral–descendant notion of their evolution influences expectations around the anatomy of missing elements, especially the foot. Weak support for long-held notions of postcranial modernity in H. erectus raises the possibility of alternative drivers of dispersal. New observations suggest that the dearth of faces in later H. erectus may mask taxonomic diversity in Asia and suggest various later mid-Pleistocene populations could derive from either Asia or Africa. Future advances will rest on the development of nuanced ways to affiliate fossils, greater transparency of implicit assumptions, and attention to detailed life history information for comparative collections; all critical pursuits for future research given the great potential they have to enrich our evolutionary reconstructions for the next fifty years and beyond.

The Australopithecus assemblage from Sterkfontein Member 4 (South Africa) and the concept of variation in palaeontology.

Interpreting morphological variation within the early hominin fossil record is particularly challenging. Apart from the fact that there is no absolute threshold for defining species boundaries in palaeontology, the degree of variation related to sexual dimorphism, temporal depth, geographic variation or ontogeny is difficult to appreciate in a fossil taxon mainly represented by fragmentary specimens, and such variation could easily be conflated with taxonomic diversity. One of the most emblematic examples in paleoanthropology is the Australopithecus assemblage from the Sterkfontein Caves in South Africa. Whereas some studies support the presence of multiple Australopithecus species at Sterkfontein, others explore alternative hypotheses to explain the morphological variation within the hominin assemblage. In this review, I briefly summarize the ongoing debates surrounding the interpretation of morphological variation at Sterkfontein Member 4 before exploring two promising avenues that would deserve specific attention in the future, that is, temporal depth and nonhuman primate diversity.

The genus Platytyphlops (Cumacea: Crustacea): A new species from Argentina, taxonomic status of Platytyphlops orbicularis (Calman, 1905), and remarks on the genus

Platytyphlops uteae n. sp. is described based on a few specimens collected off the coast of Buenos Aires Province at 1011–1712 m depth during the surveys Atlantis II 60 (1971) and Talud Continental III (2013). In addition, Platytyphlops orbicularis, a species described by W. T. Calman in 1905 based on a single fragmentary specimen from West Ireland, is briefly redescribed. Furthermore, the specimens from the east coast of USA assigned to P. orbicularis by Calman in 1912, are herein considered to be conspecific with P. uteae n. sp. These two species are closely related. P. uteae n. sp. can be easily separated from P. orbicularis by: (1) the absence of submedian carinae on the carapace (present in P. orbicularis), (2) the female carapace being as wide as long (wider than long in P. orbicularis); and (3) the fifth pereopod as long as the fifth pereonite (much shorter than the fifth pereonite in P. orbicularis). Platytyphlops is a diverse genus that currently encompasses 24 species. Based on morphological data, three species groups within this genus are herein proposed. In addition, the bathymetrical range of all the species currently in Platytyphlops are updated and compared.

A reappraisal of Jeddaherdan aleadonta (Squamata: Acrodonta), the purported oldest iguanian lizard from Africa

Jeddaherdan aleadonta Apesteguía et al., 2016 is currently known as the first and single Mesozoic iguanian lizard from Africa. The original description and age of the holotype and only known specimen (i.e. a dentary fragment bearing five teeth) are revised here. We show that this fragmentary specimen was misinterpreted anatomically, does not come from Cretaceous beds but is instead Quaternary in age, and must be assigned to an indeterminate species of Uromastyx (spiny-tailed lizards). Therefore, the genus Jeddaherdan is considered a junior synonym of Uromastyx, and the species J. aleadonta (= Uromastyx sp.) is considered a nomen dubium. Our results refute the presence of iguanian lizards in the Mesozoic of Africa and have major implications for reconstructing the evolution and palaeobiogeography of this group.

Osseous Microanatomy and Histochemical Characterization in Species, Gender Determination and Age Estimation

Background: Bone is a tissue of particular interest, because the hard tissue of the skeleton is normally well preserved and details of microscopic structure can be seen in specimens many centuries old. The microscopic structure of bone can be utilized for identification of unknown bone samples in forensic odontology. Physical anthropologists may encounter complete or fragmentary specimens of bone in which standard anthropometric methods provide inconclusive or questionable information. If the histological structure of such material could reveal, with reasonable accuracy, details of species, age, and gender, it would be a useful and valuable laboratory tool. Materials and Methods: A cross-sectional analysis of formalin fixed paraffin embedded sections from biopsied lesions (5 cases each of goat bone, 5 cases of chicken bone specimen, 5 cases of human male bone specimen, 5 cases of human female bone specimen) was done. The variation of the trabeculae by measuring the average width of trabeculae, the average marrow space, and the ratio of the above two through morphometric analysis was assessed. The observational percentage variation amongst the species by number of osteons, osteocytes shape i.e., -spindle, elliptical and round, presence of inflammation was noted. The stroma and hard tissue for Collagen characterization (Special stains)Type, orientation and maturity using Picrosirus stain, Sub intimal fibrosis surrounding the bone using Van Gieson, Percentage of mature and immature bone pattern using Azan stain was analyzed. Result: Chicken bone shows absence of osteons in comparison to human bone with increased number of osteocytes. Goat bone shows plexiform pattern with scattered haversian canals more comparable to human bone architecture. Average human Haversian canal diameter was greater than non-human mammalian species. Azan staining helped in differentiation of mature from immature bone. Picrosirus staining helped in establishing collagen type, orientation and thickness. Sub intimal fibrosis surrounding the bone was checked using Van Gieson staining. Discussion: The complexities of bone tissue and its growth processes are such that misinterpretations of a critical nature can be made if the observer is not well informed on the multitude of basic details dealing with Osteogenesis, remodelling, and comparative histology. Conclusion: Bone histomorphological assessment is an effective method for species identification, gender determination and age estimation by fragmentary osseous remains.

New therizinosaurid dinosaur from the marine Osoushinai Formation (Upper Cretaceous, Japan) provides insight for function and evolution of therizinosaur claws

The record of therizinosaurs is rich in Asian countries such as Mongolia and China. Fragmentary therizinosaur specimens have been reported from the Lower and Upper Cretaceous deposits in Japan. One of these specimens, from the lower Campanian Osoushinai Formation in Nakagawa Town of Hokkaido Prefecture, was previously identified as a maniraptoran theropod dinosaur, possibly therizinosaur, but its taxonomic status remained unresolved. This study re-examines the specimen and provides a more detailed description and attempts to resolve its taxonomic status. Our study demonstrates that it is a new taxon, Paralitherizinosaurus japonicus gen. et sp. nov., because it shows a unique combination of characters in the metacarpal I and unguals. Our phylogenetic analysis places this new taxon within an unresolved clade of Therizinosauridae in the strict consensus tree. The 50% majority-rule consensus tree shows better resolution within Therizinosauridae, showing an unresolved monophyletic clade of Paralitherizinosaurus, Therizinosaurus, Suzhousaurus, and the Bissekty form. Geometric morphometric analysis suggests that Paralitherizinosaurus unguals most closely resemble Therizinosaurus unguals in being slender and has weak flexor tubercles. This study also shows an evolutionary trend in ungual shape, which associates a decrease in mechanical advantage, development of flexor tubercle, and hypothesized output (product of mechanical advantage and development of flexor tubercle) in derived therizinosaurs, supporting the hook-and-pull function of claws to bring vegetation to its mouth. Paralitherizinosaurus is the youngest therizinosaur from Japan and the first recovered from the marine deposits in Asia. This suggests a long temporal existence of therizinosaurs at the eastern edge of the Asian continent and adaptation of therizinosaurs to coastal environments.

New material of Loricata (Archosauria: Pseudosuchia) from the Late Triassic (Carnian, Hyperodapedon Assemblage Zone) of southern Brazil

Loricata is a group of hypercarnivorous pseudosuchian archosaurs that reached the status of top predators in ecosystems from the Middle to Late Triassic. Although the record of taxa pertaining to this group is abundant in rocks of the lower portion of the Santa Maria Supersequence (Pinheiros-Chiniquá Sequence, Dinodontosaurus Assemblage Zone) of southern Brazil, it becomes far scarcer in subsequent units (i.e., Santa Cruz Sequence, Santacruzodon Assemblage Zone; Candelária Sequence, Hyperodapedon Assemblage Zone) and even absent (upper Candelária Sequence, Riograndia Assemblage Zone). Therefore, it is important to reference and study new specimens of the latter units. Herein, we report a new record of Loricata based on a fragmentary specimen of the lower Candelária Sequence. Its morphology, along with a phylogenetic analysis, support the loricatan affinities of this new specimen, although its fragmentary nature precludes less-inclusive associations. So far, the only loricatan collected for the lower portion of the Candelária Sequence was Rauisuchus tiradentes, known from several elements, most of which may represent a single individual. Thus the new specimen adds to the record of loricatans in this unit.

A new plastomenid trionychid (Testudines: Pan-Trionychidae) from Milk River Formation of southern Alberta (Cretaceous: Santonian)

The pre-Campanian trionychid fossil record in North America is composed of highly fragmentary specimens, which are often not identifiable beyond Pan-Trionychidae. Here, we describe a new species of plastomenid soft-shelled turtle based on a partial shell (ROM 56647) from the Santonian Milk River Formation of southern Alberta, estimated at approximately 84 Ma. This represents the oldest relatively complete shell of a trionychid from North America. Plastomenidae, a pan-trionychid clade known only from the fossil record, is classically characterized by the complete suturing of its posterior plastral bones along the midline, a crescent-shaped entoplastron, and enlarged costals VIII. ROM 56647 has a unique combination of plastomenid characters (i.e., mid-line contact of hypoplastra and xiphiplastra, anteroposteriorly long eighth costal) and apomorphies (an emarginate nuchal, enlarged tubercles on the carapace, a wide pygal notch with a straight anterior edge, and a fused hyo-hypoplastron) that allows us to identify it as a new taxon, Jimemys glaebosus gen. et sp. nov. Phylogenetic analysis places J. glaebosus within Plastomenidae as the sister taxon to a clade containing Plastomenus, Helopanoplia, and Hutchemys. This phylogenetic position implies that Aspideretoides foveatus Leidy, 1856, Atoposemys, and Gilmoremys, all of which are more basal within Plastomenidae, had ghost lineages extending at least to the Santonian. As the oldest pan-trionychid that is diagnostic to the species level in North America, J. glaebosus provides new insights into both the early evolution of trionychids in North America and the biodiversity of southern Alberta during a poorly sampled time in the Late Cretaceous of North America.