Nicholas C Fraser

National Museums Scotland · Department of Natural Sciences

Fissure fill deposits from the Late Triassic to Early Jurassic of England and Wales preserve a diverse small tetrapod fauna including procolophonids, an important group of Permian and Triassic parareptiles that radiated across Pangaea following the end‐Permian extinction event. Procolophonids are currently known from two fissure fill sites: incompl...

Living mammal groups exhibit rapid juvenile growth with a cessation of growth in adulthood¹. Understanding the emergence of this pattern in the earliest mammaliaforms (mammals and their closest extinct relatives) is hindered by a paucity of fossils representing juvenile individuals. We report exceptionally complete juvenile and adult specimens of t...

The non-archosauriform archosauromorph Dinocephalosaurus orientalis was first described from the Upper Member of the Guanling Formation (late Anisian, Middle Triassic) of Guizhou Province by Li in 2003 on the basis of a complete articulated skull and the first three cervical vertebrae exposed in dorsal to right lateral view. Since then, additional...

Scleromochlus taylori is one of the most enigmatic members of the herpetofauna from the Lossiemouth Sandstone Formation (Upper Triassic) of Elgin (Moray, Scotland). For many years it was thought to be closely related to pterosaurs and dinosaurs, but the anatomy of this animal is difficult to interpret because of the notoriously poor preservation of...

The fissure fill localities of southwest England and South Wales are well‐known for preserving rich assemblages of predominantly small‐bodied Late Triassic to Early Jurassic tetrapods, but many aspects of these assemblages remain contentious. The age of the Late Triassic fissures is disputed, with some lines of argument suggesting a latest Triassic...

The transition between Early to Middle Jurassic was significant in pterosaur evolution, when these volant reptiles exploded in diversity alongside dinosaurs and other animals. It has long been thought, however, that pterosaurs did not develop large wingspans until after the Jurassic, a notion challenged by the recent discovery of Dearc sgiathanach...

A long neck is an evolutionary innovation convergently appearing in multiple tetrapod lineages, including groups of plesiosaurs, non-archosauriform archosauromorphs, turtles, sauropodomorphs, birds, and mammals. Among all tetrapods both extant and extinct, two Triassic archosauromorphs, Tanystropheus and Dinocephalosaurus, have necks that are parti...

The affinities of extinct organisms are often difficult to resolve using morphological data alone. Chemical analysis of carbonaceous specimens can complement traditional approaches, but the search for taxon-specific signals in ancient, thermally altered organic matter is challenging and controversial, partly because suitable positive controls are l...

Pterosaurs, the first vertebrates to evolve powered flight, were key components of Mesozoic terrestrial ecosystems from their sudden appearance in the Late Triassic until their demise at the end of the Cretaceous1–6. However, the origin and early evolution of pterosaurs are poorly understood owing to a substantial stratigraphic and morphological ga...

Pterosaurs were the first vertebrates to evolve flight¹,² and include the largest flying animals in Earth history.³,⁴ While some of the last-surviving species were the size of airplanes, pterosaurs were long thought to be restricted to small body sizes (wingspans ca. <1.8–1.6 m) from their Triassic origins through the Jurassic, before increasing in...

Archosauromorph reptiles underwent rapid lineage diversification, increases in morphological and body size disparity, and expansion into new adaptive landscapes. Several of the primary early archosauromorph clades (e.g. rhynchosaurs) are easy to differentiate from others because of their characteristic body types, whereas the more lizard‐like and c...

The Middle Jurassic witnessed the early diversification of mammal groups, including the stem‐mammalian clade, Docodonta. Recent discoveries in China indicate docodontans exhibited ecomorphological diversity akin to small‐bodied mammals living >100 million years later, in the Cenozoic. Our understanding of the emergence of this ecological diversity...

We describe a new small-bodied coelophysoid theropod dinosaur, Pendraig milnerae gen. et sp. nov, from the Late Triassic fissure fill deposits of Pant-y-ffynnon in southern Wales. The species is represented by the holotype, consisting of an articulated pelvic girdle, sacrum and posterior dorsal vertebrae, and an associated left femur, and by two re...

The historical clade “Protorosauria” represents an important group of archosauromorph reptiles that had a wide geographic distribution between the Late Permian and Late Triassic. “Protorosaurs” are characterized by their long necks, which are epitomized in the genus Tanystropheus and in Dinocephalosaurus orientalis . Recent phylogenetic analyses ha...

In the Late Triassic the landscape NE of present-day Bristol, SW England was dominated by Carboniferous Limestone ridges and cuestas that became progressively buried by continental Mercia Mudstones and finally inundated during the Rhaetian marine transgression. Mussini et al. (2020) adopt the assertions of earlier collaborators back to Whiteside an...

Docodonta are one of the earliest diverging groups of mammaliaforms, and their morphology provides key information on the transition between non-mammalian cynodonts and Mammalia. We describe the partial skulls of two docodontans Borealestes serendipitus and Borealestes cuillinensis sp. nov. from the Kilmaluag Formation (Middle Jurassic: Bathonian),...

The postcranial morphology of the extremely long-necked Tanystropheus hydroides is well-known, but observations of skull morphology were previously limited due to compression of the known specimens. Here we provide a detailed description of the skull of PIMUZ T 2790, including a partial endocast and endosseous labyrinth, based on synchrotron microt...

The Late Triassic fauna of the Lossiemouth Sandstone Formation (LSF) from the Elgin area, Scotland, has been pivotal in expanding our understanding of Triassic terrestrial tetrapods. Frustratingly, due to their odd preservation, interpretations of the Elgin Triassic specimens have relied on destructive moulding techniques, which only provide incomp...

Tanystropheus longobardicus is one of the most remarkable and iconic Triassic reptiles. Mainly known from the Middle Triassic conservation Lagerstätte of Monte San Giorgio on the Swiss-Italian border, it is characterized by an extraordinarily long and stiffened neck that is almost three times the length of the trunk, despite being composed of only...

As ecosystems recovered from the end-Permian extinction, many new animal groups proliferated in the ensuing Triassic. Among these were the sauropterygians, reptiles that evolved from terrestrial ancestors and transitioned to a marine environment. The first sauropterygians were small, marine-adapted taxa such as pachypleurosaurs, which are known fro...

The partial skeleton of the docodont mammal, Borealestes serendipitus (Docodonta, Mammaliaformes), was recovered from Skye in 1972, and is now held at National Museums Scotland. It includes the cranium, upper and lower tooth rows and a partial postcranial skeleton. It is the most complete Jurassic mammal fossil described from the UK to date, and on...

The early evolution of turtles continues to be a contentious issue in vertebrate palaeontology. Recent reports have suggested that they are diapsids1-6, but the position of turtles within Diapsida is controversial7-12 and the sequence of acquisition of turtle synapomorphies remains unclear1-3. Here we describe a Triassic turtle from China that has...

Stan Wood had a gift for finding exceptional Early Carboniferous fossils. Among them are 32 type specimens. His discoveries significantly changed our understanding of the history of life on Earth. Many of the fossils he collected are on display in museums across the UK and the localities he discovered continue to yield important new material. Here...

Over the past two decades, a wealth of marine and terrestrial reptiles, including protorosaurian archosauromorphs, has been described from Triassic shales and limestone layers in southern China. Recovered from the eastern margin of the Tethys Ocean, these forms often show remarkable similarities to taxa that were previously known and described from...

Atoposaurids were a clade of semiaquatic crocodyliforms known from the Late Jurassic to the latest Cretaceous. Tentative remains from Europe, Morocco, and Madagascar may extend their range into the Middle Jurassic. Here we report the first unambiguous Middle Jurassic (late Bajocian–Bathonian) atoposaurid: an anterior dentary from the Isle of Skye,...

Tritylodontidae was a successful advanced cynodont clade with a close relationship to mammals, but falling outside the clade Mammaliaformes. Stereognathus ooliticus was the first tritylodontid to be named and described in 1854, but since then no comprehensive description for this species has been produced. A second species, S. hebridicus, was named...

Eggs or embryos have been reported in various groups of fossil reptiles, where viviparity is a common mode of reproduction in aquatic taxa such as the ichthyopterygians, some groups of sauropterygians, mosasauroids, some taxa of choristoderans and certain protorosaurs. Here, we describe a complete embryo of a marine protorosaur, based on a well-pre...

The Middle and early Late Triassic of southern China is well known for a remarkable diversity of marine vertebrates, particularly reptiles, including an abundance of intriguing new forms (e.g., Jiang et al., 2005; Hu et al., 2011; Li et al., 2016). Here we describe a new diapsid from Yunnan Province. It possesses an elongate neck that exhibits a re...

We describe a new species of the aetosaur Coahomasuchus , C . chathamensis , based on an incomplete, but largely articulated, anterior portion of a skeleton recovered from a quarry in the Upper Triassic Pekin Formation of Chatham County, North Carolina. This is only the second documented occurrence of Coahomasuchus , with the other being the holoty...

The end-Devonian to mid-Mississippian time interval has long been known for its depauperate palaeontological record, especially for tetrapods. This interval encapsulates the time of increasing terrestriality among tetrapods, but only two Tournaisian localities previously produced tetrapod fossils. Here we describe five new Tournaisian tetrapods (Pe...

The end-Devonian to mid-Mississippian time interval has long been known for its depauperate palaeontological record, especially for tetrapods. This interval encapsulates the time of increasing terrestriality among tetrapods, but only two Tournaisian localities previously produced tetrapod fossils. Here we describe five new Tournaisian tetrapods ($\...

The poorly understood Triassic reptile Drepanosaurus is known for its excessively large claws. New discoveries demonstrate a remarkable modification of the bones in the wrist and forearm, a significant departure from the typical five-digit tetrapod limb.

Contrary to the fast radiation of most metazoans after the end-Permian mass extinction, it is believed that early marine reptiles evolved slowly during the same time interval. However, emerging discoveries of Early Triassic marine reptiles are questioning this traditional view. Here we present an aberrant basal ichthyosauriform with a hitherto unkn...

Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts...

Atoposaurids were a clade of semiaquatic crocodyliforms known from the Late Jurassic to the latest Cretaceous. Tentative remains from Europe, Morocco, and Madagascar may extend their range into the Middle Jurassic. Here we report the first unambiguous Middle Jurassic (late Bajocian–Bathonian) atoposaurid: an anterior dentary from the Isle of Skye,...

Fossils of Mesozoic vertebrates are rare in Scotland, particularly specimens of marine reptiles such as plesiosaurs and ichthyosaurs. We describe a suite of ichthyosaur fossils from the Early to Middle Jurassic of Skye, which to our knowledge are the first ichthyosaurs from Scotland to be described and figured in detail. These fossils span approxim...

Aetosaurs are an extinct clade of quadrupedal, heavily armored archosaurs that had a worldwide distribution during the Late Triassic. Aetosaur fossils from the Upper Triassic Pekin Formation in the Deep River Basin of North Carolina (U.S.A.) consist primarily of isolated osteoderms and, rarely, more associated material. Here we describe a new genus...

Proxy records of hydrologic variability in the West Pacific Warm Pool (WPWP) have revealed wide-scale changes in past convective activity in response to orbital and sub-orbital climate forcings. However, attributing proxy responses to regional changes in WPWP hydrology versus local variations in precipitation requires independent records linking th...

(Actually the introduction—no abstract) Research at the Solite Quarry (North Carolina–Virginia, USA) has altered our understanding of the depositional envi- ronment that preserved an exquisite Lagerstätte of Triassic flora and fauna of the Dan River–Danville basin. Data from the Solite Quarry indicate an alternative depositional environ- ment (shal...

Proxy records of hydrologic variability in the West Pacific Warm Pool (WPWP) have revealed wide-scale changes in past convective activity in response to orbital and sub-orbital climate forcings. However, attributing proxy responses to regional changes in WPWP hydrology versus local variations in precipitation requires independent records linking th...

A new species of Macrocnemus is described on the basis of two incomplete specimens from the Lower Ladinian Prosanto Formation of southeastern Switzerland. The new form can be distinguished by its gracile limb elements and having a noticeably longer tibia than either Macrocnemus bassanii or Macrocnemus fuyuanensis. One of the new specimens exhibits...

A new protorosaur is described on the basis of a single specimen from the Ladinian of southern China. Although it has been greatly crushed, it still preserves clear details of the skull and axial skeleton. It possesses a neck that is longer than the trunk and is similar to tanystropheids in having 12 or 13 cervicals. Unusual among protorosaurs, the...

The earliest record of a seed with a pappus-like, parachute seed dispersal mechanism, Edenia villisperma gen. et sp. nov., is described from the Upper Triassic of the eastern United States. The seed is small and roughly triangular. Clus- ters of long hairs emerge from a whorl of at least five circular scars just below the proximal end. This morphol...

The Post Quarry, within the lower part of the type section of the Upper Triassic Cooper Canyon Formation in southern Garza County, western Texas, contains a remarkably diverse vertebrate assemblage. The Post Quarry has produced: the small temnospondyl Rileymillerus cosgriffi; the metoposaurid Apachesaurus gregorii; possible dicynodonts and eucynodo...

Remains of the extinct sphenophyte (horsetail) Neocalamites are most widespread in the Middle–Upper Triassic and are typically represented by stem and leaf fragments. Here we report on spectacular new finds of Neocalamites from the Late Triassic Yangcaogou Formation in Liaoning Province, China that include bedding surfaces dominated by nearly compl...

A new specimen of the protorosaur Macrocnemus fuyuanensis, from the Zhuganpo Member of the Falang Formation at Fuyuan (Yunnan Province, southwestern China), is described and compared with Macrocnemus bassanii. The new specimen is the first in the genus Macrocnemus that clearly shows details of the preorbital region of the skull. A large, plate-like...

The first appearance of dinosaurs during the early Late Triassic coincided with marked faunal changes in terrestrial ecosystems. Most of the major groups of extant tetrapods (or their proximate sister-taxa), including mammaliaforms, crocodyliform archosaurs, lepidosaurs and turtles, also first appeared in the fossil record during the Late Triassic....

The rich, fossiliferous Triassic sediments exposed in the Virginia Solite Quarry include a 34-mm-thick “insect layer” that is notable for detailed preservation of soft-bodied invertebrate and vertebrate remains. We describe this unique Konservat-Lagerstätte and use sedimentologic and geochemical analyses to interpret the environmental conditions ne...

The protorosaur Tanystropheus longobardicus is well known from the Middle Triassic of alpine Europe. It has been described on the basis of a number of specimens that apparently range from juvenile to adult. The largest specimens have a total body length of approximately 3 m. Here we report on the first occurrence of a large tanystropheid from the M...

A new genus and species of protorosaur is described on the basis of material originally referred to Tanystropheus antiquus from the Upper Buntsandstein of the Black Forest, Germany. The new taxon is characterized by eight cervical vertebrae that bear markedly elongate cervical ribs, a shagreen of denticles covering the vomers, palatines and pterygo...

Two Triassic sphenodontid reptiles, Brachyrhinodon taylori and Polysphenodon mulleri, are redescribed. Both genera are blunt-snouted forms but, as a result of distortion in the original fossils, the degree to which the snouts are shortened has previously been over-elaborated. An elongate temporal region and an interorbital width exceeding that of t...

Recent finds of remarkable fossil plants from the Upper Triassic Yangcaogou Formation in Liaoning Province, PR China include branched, cupule-bearing structures referable to the corystosperm ovulate organ Umkomasia. This material is described and assigned to the proposed new species Umkomasia asiatica. The collection includes numerous isolated cupu...

The first protorosaur from the Middle Triassic of China, Dinocephalosaurus orientalis Li is known from two specimens: the holotype (an isolated skull in association with the first three cervical vertebrae), and a referred specimen (an almost complete, associated and partially articulated specimen lacking the tail). This material is here described i...

The Virginia Solite Quarry occurrence of exceptionally abundant and uniquely preserved specimens of the tetrapod Tanytrachelos ahynis offers an opportunity to quantify multiple aspects of vertebrate taphonomy. Presence or absence of 128 skeletal elements and of 136 skeletal variables were recorded for 99 specimens from two distinct layers within th...

The most diverse and best-preserved early fauna of flies (order Diptera) is described from the Late Carnian (Late Triassic, ca. 220 Ma) of Virginia, USA. Complete flies are preserved as aluminosilicate films on very fine-grained shales from the Cow Branch Formation, which is part of the Newark Supergroup of Early Mesozoic rift basins from eastern N...

A new genus and species of protorosaur is described on the basis of material originally referred to Tanystropheus antiquus from the Upper Buntsandstein of the Black Forest, Germany. The new taxon is characterized by eight cervical vertebrae that bear markedly elongate cervical ribs, a shagreen of denticles covering the vomers, palatines and pterygo...

A.: Revision of the bizarre Mesozoic scor-pionflies in the Pseudopolycentropodidae (Mecopteroidea). Insect Syst. Evol. 36: 443-458. Copenhagen, November, 2005. ISSN 1399-560X. The Mesozoic family Pseudopolycentropodidae presently consists of seven described species from the mid-Triassic to the Late Jurassic of Europe and Asia. Pseudopolycentropus p...

An isolated skull of a procolophonid is described from the Owl Rock Member of the Chinle Formation in the Abajo Mountains of southeast Utah. Although poorly pre-served, this specimen exhibits features that demonstrate a phylogenetic relationship with leptopleuronine procolophonids. These include the dentition, the greatly expanded orbitotemporal op...