An enormous prehistoric whale named Perucetus colossus might be the heaviest vertebrate to have ever lived. Previously, the heaviest animal known to science was the blue whale (Balaenoptera musculus). These whales can weigh up to 190 tonnes. The newly described P. colossus is estimated to have weighed between 85 and 340 tonnes. Researchers writing in the academic journal “Nature” postulate that this animal pushes extreme size in cetaceans to a much earlier phase in their evolutionary development.

Perucetus colossus

Fossils of this leviathan were discovered in the desert on the southern coast of Peru. Palaeontologist Mario Urbina spent decades painstakingly looking for fossils. In 2010, he made an exceptional discovery. Other field team members were puzzled when photographs of the unusual objects jutting out of the 39-million-year-old sediments were examined.

These huge and odd-shaped objects were vertebrae from an immense skeleton. Each bone weighed over a hundred kilograms and four ribs found in association with the thirteen vertebrae measured approximately 1.4 metres in length. Several expeditions had to be organised to excavate and remove the colossal fossils from the remote location.

A New Species of Basilosaurid Whale

The remarkable fossils are now part of the vertebrate collection housed at the Museo de Historia Natural, Universidad Nacional Mayor San Marcos in Peru. Perucetus has been assigned to Basilosauridae family. These whales were the earliest cetaceans to fully transition to an aquatic lifestyle. Basilosaurids are known from the early Eocene to the late Eocene and were geographically widespread.

Perhaps the most famous of all these ancient whales is Basilosaurus. It was an apex predator and some species could have reached lengths of twenty metres or so, approximately the same length as Perucetus colossus, but Basilosaurus was much lighter.

Picture credit: Everything Dinosaur

The picture above depicts a Basilosaurus. Fossils indicate that Basilosaurus was much more slender and serpent-like when compared to the newly described Perucetus. The drawing is based on the CollectA Basilosaurus replica.

To view the not-to-scale CollectA model range: CollectA Age of Dinosaurs Popular Models.

The World’s Heaviest Animal

No other known basilosaurid had such massive bones. An international team of scientists including Olivier Lambert, a palaeontologist at the Royal Belgian Institute of Natural Sciences surface-scanned the preserved bones to measure their volume. Cores were taken from one dorsal vertebra and a rib to permit an assessment of bone density and structure. Comparisons with extant whales and other extinct basilosaurids were then made.

The twenty-metre-long skeleton of the Perucetus was estimated to be two to three times heavier than the blue whale skeleton called Hope exhibited in the Hintze Hall of the London Natural History Museum. To reconstruct the body mass of Perucetus, the authors used the ratio of soft tissue to skeleton mass known in living marine mammals. With estimates ranging from 85 to 340 tonnes, the mass of Perucetus colossus falls in or exceeds the distribution of the blue whale.

Adapted to a Shallow Water Marine Environment

The scientists postulate that Perucetus was adapted to a shallow water marine environment. The tremendous weight of this cetacean, perhaps as heavy as fifty African elephants, was partly due to modifications observed in the fossil bones. The outer portions of the bones were packed out with additional bone mass, giving them a bloated appearance (pachyostosis). The internal cavities were filled with compact bone (osteosclerosis). These two anatomical traits increased the weight of the skeleton.

Co-author of the study Olivier Lambert commented:

“These modifications are not pathological, but well known in many aquatic mammals (such as manatees) and extinct reptiles who mostly lived in shallow coastal waters. The extra weight helps these animals regulate their buoyancy and trim underwater. A stable position in the water may have been useful when foraging for crustaceans, demersal fish and molluscs along the seafloor. Such a large and heavy animal may also have been able to counteract waves in high-energy waters.”

In extant cetaceans, who can dive at much greater depth and live far offshore, the bone structure is much lighter.

Evidence of Early Gigantism

It had been thought that gigantism in baleen whales was a relatively recent development in cetacean evolution. The first huge filter-feeding whales were thought to have evolved around 5 million years ago (early Pliocene Epoch). However, the discovery of Perucetus colossus pushes back the evolution of gigantism in prehistoric whales to the Eocene.

Olivier Lambert added:

“Discovering a truly giant species such as Perucetus who is affected by strong bone mass increase changes our understanding of whale evolution. Gigantic body masses have been reached 30 million years before previously assumed, and in a coastal context.”

Everything Dinosaur acknowledges the assistance of a media release from the Royal Belgian Institute of Natural Sciences in the compilation of this article.

The scientific paper: “A heavyweight early whale pushes the boundaries of vertebrate morphology” by Giovanni Bianucci, Olivier Lambert, Mario Urbina, Marco Merella, Alberto Collareta, Rebecca Bennion, Rodolfo Salas-Gismondi, Aldo Benites-Palomino, Klaas Post, Christian de Muizon, Giulia Bosio, Claudio Di Celma, Elisa Malinverno, Pietro Paolo Pierantoni, Igor Maria Villa and Eli Amson published in Nature.

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The oldest spider ever found in Germany has been scientifically described. Named Arthrolycosa wolterbeeki this ancient creepy-crawly roamed northern Germany more than 300 million years ago (Carboniferous).

The fossils of this arachnid come from the Piesberg quarry near Osnabrück in Lower Saxony. They represent the first Palaeozoic spider found in Germany.

Arthrolycosa wolterbeeki

In a recent article published in the international journal Paläontologische Zeitschrift, Dr Jason Dunlop from the Museum für Naturkunde Berlin described this ancient arthropod. The spider is between 310 and 315 million years old and was named after its discoverer, Tim Wolterbeek, who generously donated the fossil to the Museum für Naturkunde Berlin.

The spider had a body length of about one centimetre and a leg span of about four centimetres. It was about the same size as a common Wolf spider (Lycosidae). It belonged to a primitive group of arachnids known as the mesotheles, which, in contrast to most spiders today, still have a segmented abdomen. Its living relatives are found only in eastern Asia.

The fossil reveals stunning details. The silk-producing spinnerets and even hair and claws on the legs have been identified.

One of Nature’s Big Success Stories

The Arachnida are one of nature’s great success stories. More than 50,000 species of spider have been described worldwide. About a thousand species live in Germany. Spiders are also preserved as fossils. More than 1,400 extinct species are known. It is thought the first spider-like, terrestrial arthropods evolved in the Devonian. These creatures rapidly diversified and thrived in the swamps of the Carboniferous. They became important predators of insects and other small invertebrates. Some giant forms evolved, although the classification of some specimens remains controversial. For example, Megarachne servinei from the Late Carboniferous of Argentina had a leg span in excess of fifty centimetres. Once thought to be a giant spider, it has been reclassified as a bizarre eurypterid.

To read an article from 2018 about the discovery of a Cretaceous-aged spider with a whip-like tail: A Tale of a Spider with a Tail.

The Piesberg quarry is an important fossil site and was declared a National Geotope in 2019. The location has yielded numerous fossils of plants, insects and other animals, including arachnids such as scorpions. This new fossil shows that Late Carboniferous spiders also lived in the Piesberg coal forests. Spiders of this age are still extremely rare. Only twelve Carboniferous species worldwide can be positively identified as spiders, with previous records coming from France, the Czech Republic, Poland and the United States (Mazon Creek).

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

The scientific paper: “The first Palaeozoic spider (Arachnida: Araneae) from Germany” by Jason A. Dunlop published in Paläontologische Zeitschrift.

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A newly published study suggests that the Cambrian predator Anomalocaris canadensis had grasping appendages that were too weak to crack trilobite exoskeletons.

The research examined the mechanical properties of the claw-like appendages of the Late Cambrian predator Anomalocaris canadensis. The study concluded that this marine carnivore was built for speed but was not strong enough to crack the exoskeletons of trilobites.

A Nektonic, Agile Hunter

Writing in the academic journal the Proceedings of the Royal Society Biology, the researchers led by Russell Bicknell (American Museum of Natural History), show that A. canadensis was weaker than previously thought. They postulate that Anomalocaris was a fast and agile swimmer. It was nektonic, catching soft prey such as jelly fish and early vertebrates in open water. The study further refutes the idea that this large predator hunted trilobites.

This Study Supports the Conclusions of Earlier Research

Earlier research (Christopher Nedin, 1999) focused on the ring-shaped mouthparts of Anomalocaris (the oral cone). Anomalocaris mouthparts were at first misidentified. The oral cone was once thought to represent a jellyfish and named Peytoia. The lack of wear on the mouthparts was highlighted suggesting that they did not they did not come into regular contact with mineralised trilobite exoskeletons. It was proposed these radiodonts probably fed on soft-bodied organisms.

Revising the Behaviour of Anomalocaris canadensis

It had been thought that Anomalocaris was responsible for some of the scarred and crushed trilobite specimens preserved in the fossil record.

Postdoctoral researcher Russell Bicknell commented:

“That didn’t sit right with me because trilobites have a very strong exoskeleton, which they essentially make out of rock, while this animal would have been mostly soft and squishy.”

Picture credit: Everything Dinosaur

The illustration (above) is based on the recently introduced CollectA Anomalocaris replica.

To view this model range: CollectA Prehistoric Life Figures.

Examining the Grasping Appendages

This study set out to investigate whether the pair of grasping appendages located on the head were capable of ripping apart a trilobite. Burgess Shale fossil material was used to create an accurate three-dimensional model of Anomalocaris canadensis.

Natural History Museum researcher and co-author of the paper, Greg Edgecombe explained:

“Having access to specimens with the entire body preserved in the fossils allowed us to understand the anatomy of the appendages in the context of the rest of the head and the trunk. We were able to get a better picture of Anomalocaris as a living organism.”

Compared to Extant Whip Scorpions and Whip Spiders

The scientists used modern predatory whip spiders and whip scorpions as analogues. The team demonstrated that the predator’s segmented appendages were able to grab prey and could both stretch and flex. Finite element analysis, a modelling technique used in engineering, was used to identify stresses and points where the appendage would have been under strain.

The team calculated that the appendages would have been damaged while grasping hard prey such as trilobites. The researchers also used computational fluid dynamics to place the three-dimensional model of Anomalocaris in a virtual current to predict the body position it would use while swimming.

Dr Imran Rahman (London Natural History Museum) stated:

“This study emphasises the great potential of modern computer modelling methods in palaeontology. By employing techniques more commonly used in other disciplines like engineering, we can test ideas about long-extinct animals like Anomalocaris.”

This is the first time this combination of biomechanical modelling techniques has been used together in a single study. A different view of Anomalocaris canadensis has emerged. The animal was probably nektonic. A speedy swimmer, chasing soft-bodied prey in the water column with its front appendages outstretched and forward-facing.

Bicknell remarked:

“Previous conceptions were that these animals would have seen the Burgess Shale fauna as a smorgasbord, going after anything they wanted to, but we are finding that the dynamics of the Cambrian food webs were probably much more complex that we once thought.”

Everything Dinosaur acknowledges the assistance of a media release from the London Natural History Museum in the compilation of this article.

The scientific paper: “Raptorial appendages of the Cambrian apex predator Anomalocaris canadensis are built for soft prey and speed” by Russell D. C. Bicknell, Michel Schmidt, Imran A. Rahman, Gregory D. Edgecombe, Susana Gutarra, Allison C. Daley, Roland R. Melzer, Stephen Wroe and John R. Paterson published in the Proceedings of the Royal Society B.