Trilobite de l'Ordovicien découvert dans la région de Québec.
Affichage des articles dont le libellé est Paléoart: Arthropodes. Afficher tous les articles
Affichage des articles dont le libellé est Paléoart: Arthropodes. Afficher tous les articles
Silurien (artbyjrc)
* Thelodus - largest thelodont agnathan fish, 1 m long.
* Dayongaspis - largest Silurian galeaspid agnathan fish, up to 30 cms long.
* Megamastax - largest Silurian sarcoptergygian fish, 1 m long.
* Stimulograptus - largest graptolite pterobranch, 2 m long.
* Acutiramus - largest Silurian pterygotid eurypterid, 2.1 m long
* Temperoceras - largest Silurian nautiloid cephalopod, up to 2 m long.
* Xylacanthus - largest Silurian acanthodian, ~68 cms long.
* Silurolepis - largest Silurian placoderm, 50 cms long.
* Eramoscorpius - largest Silurian scorpion, 16 cms long.
* Carcinosoma - largest carsinosomatid eurypterid, 2.2 m long.
* Megalomoidea - largest Silurian bivalve, 40 cm wide.
* Terropterus - largest mixopterid eurypterid, ~1 m long.
* Arctinurus - largest Silurian trilobite, 21 cm long.
* Scyphocrinites - largest Silurian crinoid, 3 m long.
* Ateleaspis - largest Silurian osteostracan agnathan fish, 20 cms long.
Julius Csotonyi III
This is a piece I prepared for the Deep Time exhibit at the Smithsonian National Museum of Natural History, featuring a Silurian reef. The fish are Nerepisacanthus, the giant eurypterid (sea scorpion) in the background is Pterygotus, and the smaller foreground eurypterid is Eusarcana. This artwork was incorporated into the big spiral timeline at the entrance to the exhibit, next to which sits Darwin's famous quote, "...endless forms most beautiful and most wonderful have been, and are being, evolved"
It was a great honour to be selected to participate in the creation of artwork to support this amazing exhibit on the deep history of life on Earth.
Terataspis (Mario Lanzas)
Terataspis is a comparatively huge, 60 centimetre long lichid trilobite genus from the Early Devonian, about 397 million years ago. It lived in a shallow sea in what is now New York State and Ontario.
Plus d'infos ici.
Arthropleura (The Time Duck)
In Franz Kafka's famous short story "The Metamorphosis", the main character Gregor Samsa wakes up one morning just to realize he's been unaccountably turned overnight into a human-sized, unidentified arthropod (the original German text has the word Ungeziefer, which indicates parasitic insects, spiders and similar animals).
And while the reader can be confident that such a creepy transformation is extremely unlikely in the real world, there was indeed a time in the history of Earth when similarly sized multi-legged invertebrates actually used to roam the planet.
Arthropleura is a genus of millipedes that could grow up to 2,5 metres long, with a maximum estimated weight of about 50 kg.
Different species of this genus are known from various parts of Europe and North America, and lived between the Early Carboniferous and the Early Permian, 345 to 290 million years ago.
Although its remains are relatively common, all Arthropleura known fossils represent molting shells (exuviae) and are often fragmentary; the fossil trackways known as Diplichnites consisting in double, parallel rows of densely arrayed small footprints are as well attributed to this genus.
While millipeds aren't the most noticeable creatures on earth, they represent one of the oldest groups of land creatures, with their earliest representatives dating back to the Late Silurian or Early Devonian, around 420 million years ago.
They form the class Diplopoda, which forms in turn the sub-phylum Myriapoda together with centipedes (Chilopoda) and the lesser known groups Pauropoda and Symphyla, mostly including very small creatures.
The name "millipede" comes from Latin and literally means one thousand feet, although the real number of their walking appendages may vary greatly, with some species of the short pill millipedes (Glomeridae) sporting little more than 30 legs, while the recently described Australian species Eumillipes persephone has about 1,360 of them.
Differently from other arthropod groups, in millipedes most body segments bear two pairs of legs, hence the Greek-derived scientific name Diplopoda, meaning "double feet".
Unlike centipedes which are carnivorous and in many cases are able to deliver painful venomous bites, millipedes generally feed on decaying plant matter and are harmless to humans; despite their defenseless appearance, they represent a very successful group, having lived across three geologic eras and still thriving today with about 12,000 described species divided into 16 orders.
The Palaeozoic genus Arthropleura includes five currently recognized species: Arthropleura armata, A. cristata, A. fayoli, A. maillieuxi and A. zeillieri.
The picture shows a real life reconstruction of both the upper and lower side of a female individual of the type species, Arhtopleura armata; a human is shown for size scale.
Monochromatic details show three larval stage of a generic millipede, illustrating the segments and legs number increase at every moult (top left to center left); a partial underside view of a male paradoxosomatid millipede, showing the pair of modified legs used in copulation and called gonopods (bottom left); an adult Arthropleura walking and leaving its typical double track (center right) and a fossil partial exuvia (bottom right).
MAIN REFERENCES:
Rosa Fernández, Gregory D. Edgecombe, Gonzalo Giribet – Phylogenomics illuminates the backbone of the Myriapoda Tree of Life and reconciles morphological and molecular phylogenies – in Nature – 08 January 2018;
Alessandro Minelli, Sergei I. Golovatch – Myriapods – in Encyclopaedia of Biodiversity – 2013 – pages 421-432.
Acutiramus (Mario Lanzas)
Acutiramus is a genus of giant predatory eurypterid, an extinct group of aquatic arthropods. Fossils of Acutiramus have been discovered in deposits of Late Silurian to Early Devonian age. Seven species have been described, five from North America (including A. cummingsi, the type species) and two from the Czech Republic (with one of them potentially found in Australia as well). The generic name derives from Latin acuto ("acute" or "sharp") and Latin ramus ("branch"), referring to the acute angle of the final tooth of the claws relative to the rest of the claw.
D'autres infos ici.
Balhuticaris voltae
Meet the newest bivalved arthropod from the Burgess Shale!
As well as looking extremely groovy, Balhuticaris voltae is the largest bivalve arthropod and one of the largest Cambrian arthropods known to science. This funky creature was a very agile nektobenthic swimmer, meaning that they could often be found hanging out at the bottom of the sea. Its extremely unusual arch-shaped carapace has stumped researchers over its function. The eyes, however, suggest that B. voltae could calculate distance better than other arthropods. It also holds the record for Cambrian multi-segmentation with 110 pairs of limbs to its name. There is little known about the ecology of this fascinating creature, but researchers think it may have swum upside-down and collected small prey with the aid of water currents.
Paper from: A. Izquierdo-López & J-B. Carson (2022) Cell Press
Image credit: Royal Ontario Museum (ROM) / Artist Hugo Salais / Metazoa Studio
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