Three Oldest Known Snake Fossils Found From Jurassic Bathonian Jurassic Britain, Kimmeridgian Jurassic Portugal

Fossilized remains of four ancient snakes have been dated between 140 and 167 million years old - nearly 70 million years older than the previous record of ancient snake fossils - and are changing the way we think about the origins of snakes, and how and when it happened. The findings have been published in the prestigious peer-reviewed journal Nature Communications.

"The study explores the idea that evolution within the group called 'snakes' is much more complex than previously thought," says lead author and professor Michael Caldwell in the Faculty of Science at the University of Alberta. "Importantly, there is now a significant knowledge gap to be bridged by future research as no fossils snakes are known from between 140 to 100 million years ago."

The oldest known snake, from Southern England, near Kirtlington, Eophis underwoodi, is known only from very fragmentary remains and was a small individual, though it is hard to say how old it was at the time it died. The largest snake, Portugalophis lignites, from coal deposits in Portugal, near Guimarota, was a much bigger individual at nearly a meter or more in length. Several of these ancient snakes (Eophis, Portugalophis and Parviraptor) were living in swampy coastal areas on large island chains in western parts of ancient Europe, while the North American species, Diablophis gilmorei, is found in river deposits from some distance inland in Western Colorado.

This new study makes it clear that the sudden appearance of snakes, some 100 million years ago, reflects a gap in the fossil record, not an explosive radiation of early snakes. From 167 to 100 million years ago, some 70 million years, snakes were radiating and evolving towards the elongate, limb-reduced body plan characterizing the now well known, ~100-90 million year old, marine snakes from the West Bank, Lebanon, and Argentina, that still possess small but well developed rear limbs. As is always the case, the distribution of these newer oldest snakes, and the anatomy of the skull and skeletal elements, makes it clear that even older snake fossils are waiting to be found.

"Based on the new evidence and through comparison to living legless lizards that are not snakes," explains Caldwell, "the paper explores the novel idea that the evolution of the characteristic snake skull and its parts appeared long before snakes lost their legs."

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Eousdryosaurus nanohallucis: A new Dryosaurid Ornithopod From Kimmeridgian Jurassic

A new dryosaurid ornithopod (Dinosauria, Ornithischia) from the Late Jurassic of Portugal

Authors:

Escaso et al

Abstract:

A new dryosaurid ornithopod, Eousdryosaurus nanohallucis, gen. et sp. nov., is described here based on a single specimen from the Late Jurassic Alcobaça Formation of Portugal. Eousdryosaurus nanohallucis is distinguished from all other dryosaurids by eight autapomorphic features and an unique combination of characters, some of which are also shared by other dryosaurids. Eousdryosaurus is linked with Dryosauridae, because the fourth trochanter is proximally placed and widely separated from the scar for the insertion of the M. caudifemoralis longus, which is restricted to the medial surface of the femoral shaft. Phylogenetic analysis nests Eousdryosaurus in an unresolved polytomy at the base of Dryosauridae together with Callovosaurus, Dryosaurus, and Kangnasaurus. The complete pes of Eousdryosaurus, which has a phalangeal formula of 1-3-4-5-0, supports the putative autapomorphic reduction of the dryosaurid pes that also occurs in parallel in more derived ornithopods.

First Phytosaur Found in Carnian/Norian Triassic Portugal

The first phytosaur (Diapsida, Archosauriformes) from the Late Triassic of the Iberian Peninsula

Authors:

Mateus et al

Abstract:

The Triassic was first defined based on the characteristic threefold sequence of rocks that crops out across much of Europe, and many of the first records of Triassic dinosaurs, crocodile-line archosaurs, and other vertebrates were discovered in Great Britain, France, Switzerland, and Germany. These discoveries helped paint a general picture of the Triassic as a critical transitional interval in Earth’s history, during which Earth recovered from a devastating extinction and more modern terrestrial ecosystems composed of dinosaurs, crocodylomorphs, squamates, and mammals were first established (e.g., Sues and Fraser, 2010). Over the past 50 years, however, the focus of Triassic vertebrate research has shifted to the fossil-rich deposits of South America and western and northeastern North America. The European record has been overshadowed, but new discoveries are stimulating a major expansion of Triassic vertebrate work across Europe, especially in Germany and Poland (e.g., Gower, 1999; Dzik, 2001; Schoch, 2006; Dzik and Sulej, 2007).

Despite considerable exposures of Triassic terrestrial sedimentary rock, the Iberian Peninsula of southwestern Europe has to date contributed little to this renewed focus on the European Triassic vertebrate record. This situation is changing with recent descriptions of Triassic terrestrial vertebrates from Spain (e.g., Fortuny et al., 2011) and Portugal (Witzmann and Gassner, 2008; Steyer et al., 2011). Here, we describe the first Iberian record of a major clade of Triassic vertebrates, the long-snouted, semiaquatic phytosaurs that are part of the great post-Permian archosauromorph radiation (e.g., Stocker and Butler, 2013). This specimen, the posterior end of a mandible and associated teeth, was discovered in southern Portugal, 2.7 m above and about 5 m lateral to a bonebed of the temnospondyl Metoposaurus in a mudstone unit within the same stratigraphic section as Central Atlantic Magmatic Province (CAMP) basalts, in a classic northern Pangean rift sequence (Fig. 1). The discovery of this specimen helps to better constrain the age of the Portuguese site and provides further evidence that basal phytosaurs were widely distributed in areas with a monsoonal-type climate during the Triassic (e.g., Buffetaut, 1993; Brusatte et al., 2013).

Kimmeridgian/Tithonian Jurassic Sauropod Lourinhasaurus is Really a Camarasaur

Phylogenetic reassessment of Lourinhasaurus alenquerensis, a basal Macronaria (Sauropoda) from the Upper Jurassic of Portugal

Authors:

Mocho et al

Abstract:

Lourinhasaurus alenquerensis is a Portuguese Upper Jurassic dinosaur whose lectotype is one of the most complete sauropod specimens from the Portuguese fossil record and from the Upper Jurassic of Europe. It was recovered from sediments of the Sobral Formation (upper Kimmeridgian to lower Tithonian) at Moinho do Carmo (Alenquer, Portugal). The lectotype of Lourinhasaurus was first related to Apatosaurus and then tentatively related to Camarasaurus. Finally, it was established as a new taxon, Lourinhasaurus, including the Moinho do Carmo specimen. At the time of writing, Lourinhasaurus had a poor diagnosis and an unstable phylogenetic position. Revision of the Moinho do Carmo specimen has led to a detailed description and a new and more complete codification for several morphological characters. The phylogenetic analyses proposed herein considered Lourinhasaurus as a Camarasauromorpha Macronaria. This study also recovered a Camarasauridae clade incorporating Lourinhasaurus, Camarasaurus and, putatively, Tehuelchesaurus and that implies the presence of Camarasauridae in the European Upper Jurassic. Besides the strong similarity to Camarasaurus, Lourinhasaurus alenquerensis is here considered a valid taxon with 13 putative autapomorphies such as a sagittal keel on the dorsal margin of sacral neural spines, circular and deep spinoprezygapophyseal fossa on proximal caudal vertebrae, marked crest and groove bordering the lateral margin of the acetabulum in the ischium, and a marked deflection of the entire femoral shaft without lateral bulge. The apparently high number of taxa among the sauropod fauna from the Iberian Peninsula during the Late Jurassic is similar to the palaeobiodiversity recorded in formations of the same age, i.e. Morrison and Tendaguru, and does not support the hypothesis of a connection between the North America and Iberian Peninsula faunas during the later part of the Late Jurassic reflected by other faunal and floral groups.

Kimmeridgian Jurassic Postcranial Mammal Fossils From Portugal

Mammalian postcranial bones from the Late Jurassic of Portugal and their implications for forelimb evolution

Author:

Thomas Martin

Abstract:

Isolated bones of forelimb and pelvic girdle (two humeri, five ulnae, and an ilium) recovered from the Late Jurassic (Kimmeridgian) Guimarota coal mine in western central Portugal are attributed to the docodont Haldanodon exspectatus, dryolestoids, and a ?paulchoffatiid multituberculate. The larger of the two humeri is assigned to the dryolestid Dryolestes leiriensis based on size and shape. It clearly exhibits an incipient trochlea at the distal joint, suggesting that this derived character was well established among Late Jurassic dryolestidans, including Henkelotherium. Plesiomorphic characters are the prominent spherical radial condyle and the weakly developed ulnar condyle. An incipient medial keel is present in distal aspect of the humerus trochlea. The shallow olecranon fossa of the humerus corresponds to the small anconeal process of the radius. The smaller humerus with damaged distal joint is 50% smaller and cannot be assigned to a specific dryolestoid taxon. It is in the size range of the smaller Guimarota dryolestoids Krebsotherium, Drescheratherium, and Henkelotherium. One ulna differs from the dryolestoid ulnar shape by the nearly semicircular articular surface for the ulnar condyle of the humerus, the asymmetric olecranon with medial overhang, as well as the prominent anconeal process and is tentatively attributed to a paulchoffatiid multituberculate.

Trilobites From the Planet MONGO...errm...Portugal

Giant trilobites have been discovered in a rock quarry in northern Portugal.

The finding, published in the journal Geology, adds a new chapter to the story of some of the most successful creatures that ever lived, and may even challenge current specimens for the largest the planet has ever seen.

The current record holder for the largest trilobite still officially stands at the 72 centimeter (28.3 inch)-long Isotelus rex, a fossil recovered in Manitoba, Canada in the year 2000.

Last year, Artur Sa of the University of Tras-os-Montes and Alto Douro and a team of colleagues unearthed a slew of similar giants between 50 and 70 centimeters (19.7 and 27.6 inches) long in a slate quarry in Arouca, Portugal.

They also found two fossilized tail sections which they believe belonged to 90 centimeter (35.4 inch)-long animals, the biggest in the world.

"Normally trilobites in the Iberian Peninsula and throughout Spain don't get bigger than 10 centimeters (3.9 inches) long," Sa said. "In the quarry, they are normally above 30 centimeters in length."

Uber sized! 3 ft 'bites. Nice!


Abstract:

Giant trilobites and trilobite clusters from the Ordovician of Portugal
Juan C. Gutiérrez-Marco1, Artur A. Sá2,*, Diego C. García-Bellido1, Isabel Rábano3 and Manuel Valério4

1Departamento de Paleontología, Instituto de Geología Económica (CSIC-UCM), Facultad de Ciencias Geológicas, 28040 Madrid, Spain
2Departamento de Geologia, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal; and Centro de Geociências da Universidade de Coimbra, 3000-272 Coimbra, Portugal
3Museo Geominero–IGME, Ríos Rosas 23, 28003 Madrid, Spain
4Centro de Interpretação Geológica de Canelas, 4450-252 Canelas, Portugal

*E-mail: asa@utad.pt.

Large quarrying surfaces of roofing slate in the Arouca Geopark (northern Portugal), formed under oxygen-depleted conditions, have yielded a unique Ordovician fossil lagerstätte that reveals new information on the social behavior of trilobites. It provides several of the world's largest trilobite specimens (some reaching 70 cm), showing evidence of possible polar gigantism in six different species, as well as numerous examples of monotaxic and polytaxic size-segregated autochthonous trilobite clusters, some of which contain as many as 1000 specimens. These reveal a very diverse social behavior, which includes temporary refuge from predation and synchronous molting and reproduction, demonstrated for the first time in five contemporary families of three different trilobite orders from a single formation.

Link to the paper.