Stephan Spiekman

Stephan Spiekman
Natural History Museum, London · Department of Earth Sciences

PhD

About

23
Publications
4,357
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101
Citations
Introduction
I study Triassic reptile evolution. Recently, I finished my PhD dissertation at the University of Zurich on the phylogeny and palaeobiology of "Protorosauria", a group of non-archosauriform archosauromorphs that includes the iconic long-necked Tanystropheus. I am now a postdoc at the Natural History Museum in London where I study early crocodylomorphs and other archosaurs from the Late Triassic to Early Jurassic of the UK, with a focus on their evolution across the T-J boundary.
Additional affiliations
October 2020 - March 2022
Natural History Museum, London
Position
  • PostDoc Position
April 2016 - July 2020
University of Zurich
Position
  • PhD Student
Education
March 2016 - July 2020
University of Zurich
Field of study
  • Vertebrate Palaeontology
February 2014 - February 2016
Leiden University
Field of study
  • Evolution, Biodiversity, and Conservation
February 2014 - February 2016
Leiden University
Field of study
  • Evolution, Biodiversity, and Conservation (Biology)

Publications

Publications (23)
Article
Full-text available
Tanystropheus represents one of the most characteristic genera of Triassic reptiles and is typified by easily recognizable, hyperelongate cervical vertebrae. First described in 1852, isolated cervical vertebrae and other remains have been referred to the genus and various species have been erected and rejected based on this material. This has resul...
Article
Full-text available
Correctly identifying taxa at the root of major clades or the oldest clade-representatives is critical for meaningful interpretations of evolution. A small, partially crushed skull from the Late Triassic (Norian) of Connecticut, USA, originally described as an indeterminate rhynchocephalian saurian, was recently named Colobops noviportensis and rei...
Article
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
The frameshift hypothesis is a widely accepted model of bird wing evolution. This hypothesis postulates a shift in positional values, or molecular-developmental identity, that caused a change in digit phenotype. The hypothesis synthesized developmental and paleontological data on wing digit homology. The “most anterior digit” (MAD) hypothesis prese...
Article
Full-text available
In the aftermath of the Permo-Triassic mass extinction event, several reptile lineages radiated to form major components of marine faunas during the entire Mesozoic. The Lower Muschelkalk, which was deposited within a shallow inland sea in the Germanic Basin during the Middle Triassic, is one of the most important regions for understanding the earl...
Article
Full-text available
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...
Article
Full-text available
The genus Macrocnemus is a member of the Tanystropheidae, a clade of non-archosauriform archosauromorphs well known for their very characteristic, elongated cervical vertebrae. Articulated specimens are known from the Middle Triassic of Alpine Europe and China. Although multiple articulated specimens are known, description of the cranial morphology...
Article
Full-text available
Over the past decades, an increasing number of reptiles have been described from the Middle Triassic of southern parts of China. Marine reptiles such as thalattosaurs, ichthyosaurs and sauropterygians dominated these paleofaunas and are known to have had a Tethys-wide distribution. Indeed, several species have been described from both the eastern a...
Article
Full-text available
Over the past decades, an increasing number of reptiles have been described from the Middle Triassic of southern parts of China. Marine reptiles such as thalattosaurs, ichthyosaurs and sauropterygians dominated these paleofaunas and are known to have had a Tethys‐wide distribution. Indeed, several species have been described from both the eastern a...
Article
Tanystropheids were archosauromorph reptiles from the Triassic characterized by long necks composed of elongate cervical vertebrae and ribs, as is epitomized by its most recognisable genus Tanystropheus. An isolated cervical vertebra from the Winterswijk quarry was assigned to Tanystropheus antiquus in 1984. However, the genus Tanystropheus has bee...
Article
Tanystropheids were archosauromorph reptiles from the Triassic characterized by long necks composed of elongate cervical vertebrae and ribs, as is epitomized by its most recognisable genus Tanystropheus. An isolated cervical vertebra from the Winterswijk quarry was assigned to Tanystropheus antiquus in 1984. However, the genus Tanystropheus has bee...
Article
Full-text available
Abstract Prolacerta broomi is an Early Triassic archosauromorph of particular importance to the early evolution of archosaurs. It is well known from many specimens from South Africa and a few relatively small specimens from Antarctica. Here, a new articulated specimen from the Fremouw Formation of Antarctica is described in detail. It represents th...
Chapter
The aim of the present chapter is to provide a general overview of the main developmental differences among the three major mammalian groups, to characterize mammals among amniotes, and to present some crucial aspects of the anatomy and physiology of mammalian embryogenesis. We cover different aspects of embryology in a chronological order. We firs...
Article
Full-text available
Development in marsupials is specialized towards an extremely short gestation and highly altricial newborns. As a result, marsupial neonates display morphological adaptations at birth related to functional constraints. However, little is known about the variability of marsupial skull development and its relation to morphological diversity. We studi...
Conference Paper
Full-text available
The recent transfer of the palaeontological collections of the former Geologisch Museum of Delft University to Naturalis Biodiversity Center (Leiden) has led to the rediscovery of the skull and mandible of the ceratopsian dinosaur Protoceratops. The specimen originates from Campanian aeolian sandstone deposits of the Flaming Cliffs in Mongolia, hav...
Conference Paper
The recent transfer of the palaeontological collections of the former Geologisch Museum of Delft University to Naturalis Biodiversity Center (Leiden) has led to the rediscovery of the skull and mandible of the ceratopsian dinosaur Protoceratops. The specimen originates from Campanian aeolian sandstone deposits of the Flaming Cliffs in Mongolia, hav...

Projects

Projects (3)
Project
1) Re-examine the osteology of the holotype of Macrocnemus fuyuanensis. 2) Use synchrotron microtomography to describe the cranial elements and reconstruct the cranium of Macrocnemus bassanii
Archived project
Since Staringia 11 appeared in 2003, a wealth of new fossils has emerged from the Winterswijkse Steengroeve. This has motivated the NGV en her Workgroup Muschelkalk Winterswijk to release a new Staringia on the topic. Local specialists and professional researchers have collaborated on an elaborate overview of the geology, palaeontology, and history of this unique locality.