Scientists have announced the discovery of a new spinosaur species from Portugal. Iberospinus (I. natarioi), from Lower Cretaceous deposits associated with the Papo Seco Formation. Its discovery further supports the theory that these enigmatic theropods originated in western Europe.

Estimated to have been around eight metres in length, Iberospinus is the third spinosaur* to have been described based on fossil material found on the Iberian Peninsula. The scientific description of this taxon reinforces the idea that Iberia was a hotspot for spinosaur biodiversity, with several endemic genera having been identified from fossils found in this region.

Life reconstruction of Iberospinus natarioi (ML1190) showing three-dimensional digitalisation of some of the fossil bones, along with reconstructed musculature. Upper picture – right lateral view; Lower picture – anterolateral left view. Picture credit: Victor Feijó de Carvalho.

Picture credit: Victor Feijó de Carvalho

Iberospinus natarioi “Natário’s Iberian Spine”

Researchers Octávio Mateus and Darío Estraviz-López (NOVA School of Science and Technology, Caparica, Portugal), writing in the open-access journal PLOS One reassessed fossil material, originally found in 1999 and attributed to Baryonyx, combining this new study with an analysis of further fossil material recovered from the excavation site in the summer of 2020.

The scientists, both of whom work at the famous Museu da Lourinhã, Lourinhã (Portugal), identified a number of unique characteristics in the fragmentary fossils that permitted them to propose a new taxon. For example, CT scans revealed Iberospinus has a unique neurovascular system associated with the Meckelian groove in the lower jaw. The anterior portion of the lower jaw has a straight-profile and does not point upwards, an anatomical trait seen in other spinosaurs. The partial pubis is thickened towards its distal end and these autapomorphies permitted the erection of a new taxon

A New Spinosaur from Portugal

Iberospinus has been classified as a basal member of the Spinosauridae as its skeleton shows an intermediate condition between early tetanuran theropods and spinosaurids.

The dinosaur’s genus was inspired by the Roman name for the Iberian Peninsula and “spinus” from the Latin for spine in recognition of the long neural spines associated with spinosaurids. The species name honours amateur fossil collector Carlos Natário, who discovered the holotype fossil (specimen number ML1190) in 1999 and helped to ensure that it was placed within the vertebrate fossil collection of the Museu da Lourinhã.

A skeletal drawing of the newly described basal spinosaurid Iberospinus natarioi. The red coloured bones represent known fossil material. Note the scale bar = 1 metre. Picture credit: Octávio Mateus and Darío Estraviz-López modified from an original figure by Scott Hartman.

Picture credit: Octávio Mateus and Darío Estraviz-López modified from an original figure by Scott Hartman

Different Spinosaurs Co-existing in the Same Environment.

The large tooth complete with root was also described in the scientific paper. It possesses characters associated with the Baryonychinae subfamily of spinosaurs. The tooth crown is strongly recurved whilst more advanced and geologically younger members of the Spinosauridae such as Spinosaurus aegyptiacus tend to have straighter, conical teeth.

This reassessment of Iberian theropod fossil material demonstrates that different spinosaurid taxa co-existed within the same environment. The occurrence of more than one spinosaurid genus in a relatively restricted geographical area has been reported before, most recently with the naming of two new genera of spinosaurs (Riparovenator milnerae and Ceratosuchops inferodios) that co-existed in the Lower Cretaceous of southern England with Baryonyx (B. walkeri).

To read Everything Dinosaur’s earlier article about the recently described Isle of Wight spinosaurs: Two New Spinosaurids Described from the Isle of Wight.

Tooth from the upper jaw of I. natarioi (specimen number ML1190-3) in A, lingual, B, mesial, C, lingual, D, distal, E, occlusal, and F ventral views. Note the scale bar = 25 mm. The tooth crown is strongly curved and the tooth morphology is similar to that seen in members of the Baryonychinae. Later spinosaurs had teeth that were straighter. Picture credit: Octávio Mateus and Darío Estraviz-López.

Picture credit: Octávio Mateus and Darío Estraviz-López

Iberian Spinosaurs*

Despite the lack of relatively complete fossil material, specimens collected from the Iberian Peninsula represent one of the best accumulations of spinosaurid fossils found to date. After Baryonyx (B. walkeri) was formally named and described in 1987, several fossils from this region were ascribed to this taxon. However, more recent analysis and further fossil discoveries has led to a revision and at present three contemporaneous spinosaur taxa have been attributed to this region.

• Camarillasaurus cirugedae – from Teruel Province (north-eastern Spain). Formally named and described in 2014. Previously thought to represent a ceratosaur, now regarded as a member of the Spinosauridae.
• Vallibonaventrix cani – from the Castellón Province (north-eastern Spain). Named and described in 2019, the taxonomic position of this genus remains uncertain although the current consensus is that the fossils do represent a member of the Spinosauridae family, but there is an on-going debate as to whether Vallibonaventrix is a member of the Baryonychinae or whether it is more closely related to Spinosaurus aegyptiacus.
• Iberospinus natarioi – newly described (2022, Mateus and Estraviz-López) from the Papo Seco Formation of Cabo Espichel, Sesimbra, Portugal.

The scientific paper: “A new theropod dinosaur from the early cretaceous (Barremian) of Cabo Espichel, Portugal: Implications for spinosaurid evolution” by Octávio Mateus and Darío Estraviz-López published in PLOS One.

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A University of Manchester researcher in collaboration with a team of international scientists from China, Sweden and Switzerland has helped invertebrate palaeontologists to resolve the puzzle of how arthropods evolved gills. Dr David Legg from the Department of Earth, Atmospheric, and Environmental Sciences and his co-authors have published a scientific paper this week that describes a new genus of ancient marine arthropod from the Chengjiang biota of Yunnan Province, China. The newly described Erratus sperare swam in a shallow tropical sea some 518 million years ago (stage 3 of the Cambrian). At around 3 centimetres in length, it was no giant, but it represents a giant leap forward in the evolution of the Arthropoda.

A life reconstruction of the Cambrian Erratus sperare which has helped palaeontologists to improve their understanding of the origin of gills in the Arthropoda. Picture credit: University of Manchester.

Picture credit: University of Manchester

The Evolution of Biramous Limbs

Extant water dwelling arthropods and their extinct counterparts such as the trilobites have biramous limbs, legs that have two distinct parts or branches – one for breathing and one for walking. The inner branch is known as the endopod and the outer branch is called the exopod, together these two branches form the marine arthropod limb.

How such specialised limbs evolved was a mystery. Some of the earliest fossil arthropods, like Anomalocaris, had swimming flaps that may have doubled as gills, but until now researchers didn’t know how arthropods made the jump from these specialised flaps to the biramous limbs of modern arthropods.

The CollectA Anomalocaris model. A fantastic replica of an early apex predator. The CollectA Anomalocaris (Other Prehistoric Animal Models).

The picture (above) shows a model of an Anomalocaris, a large Cambrian predator.  This model is part of the CollectA range.

To view the CollectA range of prehistoric animal figures: CollectA Prehistoric Life Models.

Erratus sperare – A Transitional Form

Erratus sperare fossils come from the UNESCO World Heritage Site located in Yunnan Province, China. The Maotianshan shales exposed in Chengjiang County preserve a record of a Cambrian marine community that existed several million years before the Burgess Shales of British Columbia were laid down. The highly fossiliferous strata have yielded at least 196 different species, with both hard parts and soft tissues preserved.

E. sperare appears to be a transitional form, it provides a missing link between arthropods that used specialised flaps such as Anomalocaris and arthropods with biramous limbs. It has both legs and flaps.

Erratus sperare gen. et sp. nov. from the early Cambrian (Series 2, Stage 3), Chengjiang Lagerstätte, China. The fossils are approximately 518 million years old. Photograph (a) NWUS92-310, specimen formerly referred to Isoxys auritus note the carapace with short anterior spine and covering the seven most anterior body segments; the flap margin without setae (arrows); (b) details of flap 6–7; note the smooth margin. XDBZ102 (c), the complete carapace (Ca) of E. sperare in dorsal view, showing anterior spine and straight posterior margin; (d) line drawing of (a) showing cardinal spine (Cs), ventral eyes (Ey) with stalk (Es), and flaps 1–11; the ventral endopods (En) are present in the anterior trunk. Scale bars, 2 mm for (b) and 1 cm for others. Picture credit: Fu et al.

Picture credit: Fu et al

Explaining the significance of this fossil discovery, Dr David Legg commented:

“Fish aren’t the only organisms that have gills! Arthropods have gills too… they just have them on their legs. When it came to arthropods, however, we just weren’t sure where these gills came from. Thanks to this new fossil, Erratus sperare, we now have a much clearer idea. These gills also probably went on to evolve into the wings of insects and the lungs of terrestrial arthropods like spiders so were a very important innovation.”

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

The scientific paper: “The evolution of biramous appendages revealed by a carapace-bearing Cambrian arthropod” by Dongjing Fu, David A. Legg, Allison C. Daley, Graham E. Budd, Yu Wu and Xingliang Zhang published in Philosophical Transactions of the Royal Society B.

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The famous marine sediments of the Chesapeake Group, which outcrops across North Carolina, Delaware, Virginia and Maryland in the USA are regarded as some of the most extensively studied Cenozoic marine deposits in the world. The first fossil described from North America (Ecphora quadricostata) a marine snail which was scientifically described in 1685, comes from deposits associated with the Chesapeake Group (St Marys Formation)

A Miocene Fish Fossil

Many different types of fish and marine invertebrates have been named from fossils found at locations such as the Calvert Cliffs on the western shore of Chesapeake Bay (Maryland). Cetacean fossil material is also associated with these strata, along with sea cows and many seabirds such as gannets and fulmars. Marine turtles and the remains of land tortoises and freshwater crocodiles are also known.

A researcher from the Calvert Marine Museum (Maryland), is one of the authors of a recently published scientific paper that highlights a first for these Miocene-aged deposits. The partial skull of a fish has been found crammed full of tiny, fossil poo probably created by scavenging worms that once feasted on the head of the fish.

Photograph (left) of the partial skull of the Miocene Stargazer fish (ventral view). Some of the bone has broken away revealing hundreds of fossilised faecal pellets filling the braincase. A close-up view of the faecal matter (right). Picture credit: Calvert Marine Museum.

Picture credit: Calvert Marine Museum

Stargazer Skull (Astroscopus spp.)

The specimen represents the first skull completely infilled with faecal pellets ever recorded, the fossil poo (micro-coprolite) is an example of the coprulid ichnospecies Coprulus oblongus. The pellets range in size from 1 mm to 5 mm in length and the skull comes from a Stargazer fish (Astroscopus), a genus of bottom living fish that bury themselves in soft sediment lying in wait to ambush small fish and invertebrates that come within striking distance.

A fossil of worm faecal pellets from Miocene-aged deposits from southern Maryland (USA). Each pellet is approximately 3 millimetres in length. Picture credit: Calvert Marine Museum.

Picture credit: Calvert Marine Museum

Crocodile Coprolites Studied Too

Writing in the academic journal “Rivista Italiana di Paleontologia e Stratigrafia”, the researchers also describe a series of trace fossils found in preserved crocodile coprolite from the Miocene Calvert Formation. The fossil crocodile poo was tunnelled into, presumably evidence of the faeces being consumed (coprophagy). The scientists are unable to identify the organism(s) responsible for producing the burrows although the sides of the burrows preserve evidence of scratches which are thought to be feeding traces.

Crocodile coprolite broken open showing trace fossil burrows made by a coprophagus organism. Feeding gouge marks can be seen on the walls of the burrow. Length of crocodile coprolite 17.5 cm approximately. Picture credit: Calvert Marine Museum.

Picture credit: Calvert Marine Museum

Whilst these remarkable fossils might not be as awe-inspiring as the whale bones that have been found in these rocks, they provide important evidence with regards to the recycling of nutrients from faecal matter in Miocene-aged marine environments.

The scientific paper: “Coprolites from the Calvert Cliffs: Miocene fecal pellets and burrowed crocodilian droppings from the Chesapeake Group of Maryland, USA” by Stephen J. Godfrey, Alberto Collareta and John R. Nance published in Rivista Italiana di Paleontologia e Stratigrafia.