A team of international researchers have named a new species of Permian archosauromorph based on a single neck bone.  The animal has been named Manistropheus kulicki.  It provides new insights into the early evolution of archosauromorphs, a clade that includes the crocodiles, birds, pterosaurs and dinosaurs.  The cervical vertebra was discovered last century, but it has only just been scientifically described.  It was found at the famous Korbacher Spalte site in central Germany.  A fissure preserves the fragmentary and isolated remains of many Late Permian vertebrates.  The sediments are believed to around 255 million years old.

The Korbacher Spalte locality is important because it preserves evidence of tetrapods prior to the mass extinction event at the Permian-Triassic boundary.

The holotype of Manistropheus kulicki (SMNK-PAL 76022) shown in left lateral view. Picture credit: Carola Radke.

Picture credit: Carola Radke

Korbacher Spalte

The Korbacher locality is particularly well known for its many finds of the early mammal ancestor, a cynodont called Procynosuchus.  This synapsis is also jokingly referred to as the “Korbach dachshund” because of its appearance. However, scientists have now described a previously unknown species of archosauromorph reptile based on a single, well-preserved cervical vertebra. Distinctive characteristics of the fossil bone enabled the team to erect a new genus and species – Manistropheus kulicki.

Manistropheus kulicki Cervical Vertebra

The vertebra is characterised by an elongated, diamond-shaped centre and a crescent-shaped indentation on the side of the front edge of the vertebra. This gives the new genus its name – from the Old Norse Máni, the personification of the moon in Germanic mythology, and the Greek “stropheus,” meaning vertebra. Overall, the specimen shows similarities to early archosauromorphs but also shows features that are absent in other reptiles of that time. A comprehensive study of the phylogenetic relationships suggests that M. kulicki stands at the base of this important reptile lineage.  It is thought to be a basal archosauromorph.

The study also used an analysis of morphological diversity to investigate how cervical vertebrae have changed over the course of Earth’s history. The results suggest that archosauromorphs were already morphologically diverse before their extinction and that their cervical anatomy diversified rapidly in the Early Triassic.  Cervical vertebrae anatomy changed faster than other parts of the skeleton.

Lead author of the study, Dr Martín Ezcurra (CONICET) stated:

“This discovery is particularly significant because Permian archosauromorphs are extremely rare, with only five fossil species from this period known to date. Thanks to Manistropheus kulicki, we can see how diverse this group already was before the mass extinction.”

Co-author Professor Hans-Dieter Sues (Smithsonian Institute), added:

“This fossil not only proves the existence of a new species, but also supports the assumption that there was already a previously hidden diversity of archosauromorphs in the Permian period.”

Diverse Archosauromorphs Present in Equatorial Regions During the Late Permian

Professor Jörg Fröbisch (Museum für Naturkunde Berlin), another co-author of the study, highlighted the significance of the Korbach Spalte site.

He commented:

“The Korbach fissure site is proving to be a key location for better understanding life on land in the tropical regions of the supercontinent Pangaea shortly before the largest mass extinction in Earth’s history. “

The naming of this basal archosauromorph from Germany highlights the importance of continuing to explore lesser-known fossil sites.  It is especially important to explore fossil sites that provide insights into ancient ecosystems threatened with extinction.

Everything Dinosaur acknowledges the assistance of a media release from the Museum für Naturkunde Berlin in the compilation of this article.

The scientific paper: “A new late Permian archosauromorph reptile from Germany enhances our understanding of the early diversity of the clade” by Martín D. Ezcurra, Hans-Dieter Sues and Jörg Fröbisch published in the Journal of Systematic Palaeontology.

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Stunning fossils of Cambrian nectocaridids solves a half-a-billion-year-old evolutionary puzzle.  Fossil material excavated from the Sirius Passet site in North Greenland has enabled palaeontologists to identify these ancient marine invertebrates as early descendants of chaetognaths (arrow worms).  It had been proposed that these animals were a type of cephalopod.  Cephalopods are marine molluscs with tentacles and a prominent head.  Living cephalopods include cuttlefish, octopi and squid.  The extinct ammonites and belemnites were cephalopods.

This significant discovery rewrites part of the story of the Cambrian Explosion. It shows arrow worms descended from complex predators, not simple marine organisms.

Life reconstruction of Nektognathus, swimming in the Cambrian Sea. It is depicted as a nektonic predator. Picture credit: Bob Nicholls.

Picture credit: Bob Nicholls

The illustration of Cambrian life (above) was created by acclaimed palaeo-reconstruction artist Bob Nicholls.  Bob has recently been collaborating with Everything Dinosaur in the production of museum quality prehistoric animal models – Everything Dinosaur Evolution.

To learn more about these remarkable, scientifically accurate figures: Everything Dinosaur Evolution Figures.

Studying Cambrian Nectocaridids

The research team included palaeontologists from the University of Bristol, the University of Copenhagen, and the Korean Polar Research Institute. Their work builds on nine years of expeditions to Sirius Passet, a site famous for exceptional soft-tissue fossil preservation from 518 million years ago (Stage 3 of the Cambrian).

Co-author of the study, Dr Jakob Vinther, Associate Professor in Macroevolution at the University of Bristol commented:

“Sirius Passet is a treasure trove of fossils from the Cambrian Explosion. We not only find delicate soft-bodied fossils but also their digestive systems, musculature and sometimes even their nervous system.”

Research first published in 2009 examining fossils from the famous Burgess Shale deposits of British Columbia (Canada), linked nectocaridids to cephalopods.  However, some invertebrate palaeontologists remained sceptical.

Dr Vinther explained:

“Around 15 years ago a research paper, based on fossils from the famous Burgess Shale, claimed nectocaridids were cephalopods. It never really made sense to me, as the hypothesis would upend everything we otherwise know about cephalopods and their anatomy didn’t closely match cephalopods when you looked carefully.”

Field team members became excited as they found twenty-five new specimens of Cambrian nectocaridids in the Sirius Passet deposits. These are the first nectocaridids unearthed from the Sirius Passet locality. Evidence of nervous systems were preserved in some specimens.

A fossil specimen of Nektognathus discovered at Sirius Passet (northern Greenland). Picture credit: University of Bristol.

Picture credit: University of Bristol

Identifying the Ventral Ganglion

The team discovered nectocaridids with parts of their nervous system preserved as paired mineralised structures.  This new evidence helped to confirm the phylogeny of these ancient animals. Arrow worm fossils with preserved ventral ganglia – a unique nerve structure seen in modern chaetognaths (arrow worms) were also found.

Co-author of the paper, Dr Tae-Yoon Park from the Korean Polar Institute stated:

“These fossils all preserve a unique feature, distinct for arrow worms, called the ventral ganglion.”

The discovery of this structure confirms the evolutionary link between nectocaridids and arrow worms.

The holotype specimen of Nektognathus from Sirius Passet. Picture credit: Tae-Yoon Park.

Picture credit: Tae-Yoon Park

The authors of the study have erected a new nectocaridid taxon Nektognathus evasmithae. The species name honours Professor Eva Smith, the first female professor of law in Denmark and renowned human rights advocate. Dr Vinther commented that N. evasmithae was a smart and stealthy fighter, just like the Danish advocate.

Dr Park added:

“We now had a smoking gun to resolve the nectocaridid controversy. Nectocaridids share a number of features with some of the other fossils that also belong to the arrow worm stem lineage. Many of these features are superficially squid-like and reflect simple adaptations to an active swimming mode of life in invertebrates, just like whales and ancient marine reptiles end up looking like fish when they evolve such a mode of life.”

The holotype specimen of Nektognathus from Sirius Passet imaged with Electron Probe microanalysis for its carbon content. Picture credit: Mirinae Lee and Chankun Park.

Picture credit: Mirinae Lee and Chankun Park

Cambrian Nectocaridids – Dynamic, Nektonic, Agile Predators

This surprising discovery means the rather simple marine arrow worms had ancestors with much more complex anatomies and a predatory role higher up in the food chain. Cambrian nectocaridids had camera-type eyes, long antennae, and streamlined bodies for active hunting.  In contrast, extant arrow worms have eyes that are sensitive to light but are not thought to have effective vision.  The researchers conclude that the ancestors of today’s arrow worms were nektonic predators.  They filled an ecological niche similar to living squid.  Although, squids evolved much later.  Preserved gut contents indicate that Nektognathus evasmithae fed on the swimming arthropod Isoxys.

Dr Vinther commented:

“We can therefore show how arrow worms used to occupy a role much higher in the food chain. Our fossils can be much bigger than a typical living arrow worm and combined with their swimming apparatus, eyes and long antennae, they must have been formidable and stealthy predators.”

A photograph of a modern chaetognath (arrow worm) from Antarctica. Picture credit: Tae-Yoon Park.

Picture credit: Tae-Yoon Park

This study gives us a new view of Cambrian nectocaridids. Far from being early squids, they were fierce predators with an advanced anatomy.  This study helps palaeontologists to better understand Cambrian marine ecosystems.

Everything Dinosaur acknowledges the assistance of a media release from the University of Bristol in the compilation of this article.

The scientific paper: “A fossilised ventral ganglion reveals a chaetognath affinity for Cambrian nectocaridids” by Jakob Vinther et al published in Science Advances.

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