#amiskwia

[critter-creature-or-beast]

"(Drawn for the 2019 Lanzendorf contest by Christian M) “Wonderful Life” Deep in the early Cambrian ocean, below the shadow of the Cathedral Escarpment (A giant rock shelf formation), life goes on as normal. Bioluminescent Amiskwia swim in groups, trying to escape the carnivorous Opabinia. It can walk on the sea floor with legs, or swim through the water with undulating fins. Among the algae, strange sponge relatives called Choia exist, holding themselves just above the rock surface. Hallucigenia sparsa feed on the marine snow that falls, catching it on hairy tentacles and shoving it in their mouths. Aysheaia feed on sponges called Vauxia, which grow on the rocky substrate. Preying on hard shelled animals like trilobites, using its armoured antennae to break open armour, Anomalocaris dwarfs everything. It is followed closely by a shoal of Pikaia, which survive by feeding the scraps left behind when Anomalcaris finishes messily ingesting it’s prey with a horrifying circular mouth part. It can see Opabinia with the best eyes that would ever evolve for millions of years, only rivalled by dragonflies and possibly griffinflies. The Opabinia, though it has 5 compound eyes, still has a more limited resolution, and doesn’t notice the Anomalocaris swimming towards it through the gloom of the depths."

By PaleoEquii - Own work, CC BY-SA 4.0

[alphynix]

Cambrian Explosion Month #18: Stem-Gnathifera

Protostomes are the other major evolutionary branch of bilaterian animals, and by far the most numerous with over a million known modern species (and probably several times more than that still undiscovered). This lineage is distinguished from the deuterostomes based on both embryo development and genetic studies, with the two groups estimated to have shared a common worm-like ancestor sometime back in the Ediacaran Period.

For the rest of this month we'll be featuring the spiralians, a branch of the protostomes that includes modern annelid worms, molluscs, and brachiopods. Meanwhile their cousins the ecdysozoans will be the focus of the entire second month of this series, later this summer, due to their incredibly rich Cambrian fossil record.

The earliest spiralians must have diverged from other protostomes more than 558 million years ago, if Kimberella and Namacalathus really were early members of the group, but more definite fossils only appear at the start of the Cambrian (~541 million years ago) with protoconodont "teeth" – once thought to be from early vertebrates, but now recognized as probably being jaw elements from a group of spiralians known as gnathiferans.

Gnathiferans include jaw worms, micrognathozoans, arrow worms, and rotifers, and are characterized by having complex mouthparts made of chitin. The fossil record for most of them is very poor, but along with protoconodont elements there are a few exceptionally well-preserved Cambrian examples of early members of this lineage.

Inquicus fellatus is known from the Chinese Chengjiang fossil deposits (~518 million years ago). About 3mm long (0.12") and shaped like a bowling pin, it seems to have been a stem-gnathiferan possibly related to both rotifers and arrow worms.

Its fossils have been found attached onto palaeoscolecid armored worms like Cricocosmia jinningensis, in what appears to have been a commensal relationship. Inquicus attached itself by a disc at the tip of its tail, didn't seem to penetrate the worm's skin, and its mouth faced away to feed from the water around them – so it probably wasn't harming its host, instead at most being a bit inconvenient in cases where worms were carrying at least 15 of these "passengers".

———

Amiskwia sagittiformis is known from a small number of specimens in the Canadian Burgess Shale fossil deposits (~508 million years ago), with an even rarer related species Amiskwia sinica also known from Chengjiang (~518 million years ago).

For a long time its classification was a paleontological mystery, but some new specimens with better preservation seem to have finally revealed its identity – it was a gnathiferan, and possibly part of a stem lineage of early jaw worms.

Reaching about 2.5cm long (1"), it had a flattened body with two side fins and a paddle-like tail fin, a rounded head tipped with two tentacles, and complex mouth apparatus with jaw-worm-like teeth. It was probably an active swimmer that spent most of its time high in the water column well above the sea bed, potentially explaining why it so rarely fossilized even in places of exceptional preservation.

———

Nix Illustration | Tumblr | Pillowfort | Twitter | Patreon

[godteri-takk]

Is that a amiskwia he's eating for supper?

[majingojira]

Update Time: Dinosaurs and Prehistoric Animals In Mass Media

A while back, I did a post on my findings for Dinosaur Representation in Film.  Thanks to a project I’ve been aiding with, I’ve been able to greatly expand my media intact.  From what I could watch (excluding the Simpsons, because how the hell am I gonna ID prehistoric life that cartoony), here are the top 10 prehistoric animals of various groups I’ve been able to log until about March of this year. Youtube always puts out something new, so I had to cut off some things.  This covers Movies, TV Shows, Educational Shorts, Direct to Video productions, Youtube Channels, and Youtube videos (for not largely dedicated prehistoric channels/playlists).  This involved a lot of IDing I had to do myself.  So when a documentary showed a mural or sculpture, I did my best to either deduce or track down the thing so I could ID things properly.  Crystal Palace and Age of Reptiles showed up a LOT.   I even counted background skeletons for various museum shots when I could.  Because I was going ALL IN on this.  And things that used 60% stock footage were not counted to avoid repetition.  That said, footage from The Lost World (1925) got used a LOT, like, into the 21st century even!  As a final side note: SCREW Trilobites! They’re almost never IDed, and there are 40,000 of them!  Here is what I found out: 

Top 15 Dinosaurs: 

Tyrannosaurus - 306

“Raptor” (Velociraptor (90), Deinonychus (91), and Dakotaraptor/Giant Movie Villain Raptor (56) combined) - 237

Triceratops - 223

Apatosaurus ((121) and Brontosaurus(99)) - 220

Stegosaurus - 181

Allosaurus - 164

Basic Ornithomimidae (Struthiomimus (48), Ornithomimus (42), Gallimimus (30), Dromiceiomimus (8), Pelicanimimus (5), Archaeornithomimus (1) Combined) - 134

Edmontosaurus/Anatosaurus/Anatotitan - 124

Brachiosaurus - 121

Parasaurolophus - 121

Ankylosaurus - 97

Diplodicus/Seismosaurus - 93

Iguanodon - 82

Pachycephalosaurus ((56), Stygimoloch (15), Dracorex (8), and Alaskacephale (1) combined) - 80

Coelophysis - 73

Top 10 Birds/Stem Birds/Avilalans

Archaeopteryx - 84

Hesperornis - 26

Giant Moa - 23

Titanis walleri - 22

Ichthyornis (and related) - 21

Gastornis - 20

Phorurhacos - 18

Confuciusornis - 18

Teratornis - 17

Haast’s Eagle - 15

Top 10 Non-Avian Line Archosaurs

Crocodiles, Alligators, Caiman (Lumped Together) - 32

Postosuchus - 31

Sarcosuchus - 26

Desmatosuchus - 25

Deinoschus - 22

Smilosuchus - 17

Rutiodon - 17

Erythrosuchus - 17

Teleosaurus - 15

Tanystropheus - 15

Top 15 Prehistoric Mammals

Woolly Mammoth - 99

Smilodon - 83

Neanderthals - 73

“Cave Man (Cro-Magnon) - 64

Australopithecus - 59

Columbian Mammoth - 41

Equus ferrus (wild horse/tarpan) - 37

Mastodon - 37

Megalonyx - 37 

Homo erectus - 36

Woolly Rhino - 36

Glyptodon - 33

Megatheirum - 32

Dire Wolf - 31

Gigantopithecus (including Kong and knockoffs of Kong) - 31 

Top 10 Synapsids

Dimetrodon - 81

Edaphosaurus - 30

Inostrancevia/Giant Gorgonopsids - 28

Gorgonops - 25

Diictodon - 23

Placerias - 22

Lystrosaurus - 21

Moschops - 16

Lisowicia - 15

Tie: Estemmenosuchus, Secodontosaurus, Sphenacodon - 14

Top 10 Ancient Lepisosaurs

Mosasaurus - 66

Megalania - 30 (I lumped many a Slurpasaurus in here)

Tylosaurus - 30

Titanoboa - 17

Prognathodon - 14

Gigantophis - 9

Plioplatecarpus - 9

Platecarpus - 8

Dallasaurus - 7

Tetrapodphis - 7

Regular Iguana’s come in at #11. 

Top 15 Pterosaurs

Pteranodon - 153

Quetzalcoatlus - 87

Rhamphorhynchus - 55

Pterodactylus - 45

Dimorphodon - 38

Ornithocheirus - 25

Geosternbergia (was once considered a species of Pteranodon, but they are easy enough to distinguish) - 24 

Anuragnathus - 24

Hatzegopteryx - 22

Nyctosaurus  - 16

Eudimorphodon also has a 16, but I flipped a coin for this list. 

Top 10 Ichthyosaurs

Ichthyosaurus - 37

Ophthalmosaurus - 26

Temnodontosaurus - 19

Sonisaurus - 15

Mixosaurus - 13

Shastasaurus - 10

Cymbospondylus - 9

Eurhinosaurus - 7

Stenopterygius - 7

Cartorhynchus - 7

Top 10 Other Aquatic Reptiles 

Elasmosaurus - 64

Plesiosaurus - 47

Nothosaurus/”Paleosaurus” - 24

Pliosaurus - 19

Kronosaurus - 18

Liopleurodon - 16

Placodus - 12

Dolichorhynchops - 10

Cryptoclidus - 8

Placochelys - 7

Top 5 Turtles

Archelon - 21

Megalocheluys atlas/Giant Tortoises - 11

Proganocheys - 10

Odontochelys - 7

Carbonemys - 6

Top 5 Primitive Reptiles

Scutosaurus - 26

Hylomnus - 21

Drepanosaurus - 14

Mesosaurus - 10

Sharovipteryx - 9

Top ~10 Prehistoric Amphibians

Eryops - 38

Ichthyostega - 32

Tiktaalik - 23

Mastodonsaurus - 19

Koolasuchus - 16

Seymouria - 16

Metoposaurus - 15

Prionosuchus - 14

Platyhystrix - 14

Diplocaulus - 14

Acanthostega - 14

Crassigyrinus is just short of being in the grouping.  Top 15 Fish and Sharks

Coelacanths (modern (23), Mawsonia (16), Coelacanthus (7), Rebellatrix (5), and Axelrodichthys (2)) - 53

Dunkleosteus - 32

Megalodon - 31

Lungfish (combined modern species and Necroceratodus) - 28

Xiphactinus - 26

Eusthenopteron - 26

Helicoprion - 24

Bothriolepis - 22

Onchopristis - 17

Orthacanthus - 17

Cretoxyrhina - 16

Hybodus - 16

Cheirolepis - 16

Cepjhalaspis - 15

Arandaspis - 14

Top 10 Arthropods & related. 

Meganeura/Meganeuropsis - 59

Arthropleura - 27

Megalograptus - 26

Pterygotus - 24

Horeshoe Crab - 19

“Giant Spiders” - 18

Eurypterus - 18

Marella/Marellamorpha - 16

Pulmonoscorpius (Giant scorpion) - 14

Aysheaia - 12

Top 10 Trilobites

Generic Unnamed/Unidentified Trilobites - 38

Phacops - 24

REdlichia - 23

Isotelus rex - 20

Elrathia - 14

Dicranurus - 8

Asaphus - 8

Terataspis - 7

Olenoides - 7

Paradoxides - 7

If you don’t count the generic one, then the last slot is a tie for Harpes and Oryctocephalus (at 5 appearances each). 

Top 10 Mollusks

Ammonite (Generic) (Identifying the various species of Ammonite by sight is as hard as the Trilobites) - 54 

Cameroceras - 22

Belemnites - 20

Orthoceras - 16

Wiwazia  16

Nautilus - 15

Parapuzosia - 10

Clam - 10

Inoceramus - 9

Tusoteuthis/Giant Squid - 6

Top 9 Super-Primitive Basal Animals

Charnia - 20

Kimberella - 10

Dinomischus - 9

Amiskwia - 5

Ernietta - 5

Funisia - 5

Coronacollina - 4

Swartountia - 4

Cyclomedusa - 4

[gaetaniu]

Amiskwia, lo strano verme di mezzo miliardo di anni fa ha finalmente il suo posto nell'albero della vita

Amiskwia, lo strano verme di mezzo miliardo di anni fa ha finalmente il suo posto nell’albero della vita

Il fossile, Amiskwia sagittiformis dell’argillite di Burgess (508 milioni di anni), che conserva elementi bilaterali della mascella all’interno della testa. Questi elementi della mascella assomigliano a quelli visti nei rotiferi e negli gnatostomulidi, mentre il corpo assomiglia ai vermi della freccia.

Amiskwia è stato descritto originariamente dal famoso paleontologo Charles Doolittle Walcott…

[kathleenseiber]

Amiskwia Sagittiformis: Weird Chimera Worm May Finally Get Its Place In The Tree Of Life

Ribbon worm? Arrow worm? Since the discovery of its fossil over a century ago, paleontologists have speculated about what branch of evolution Amiskwia sagittiformis was on. Charles Doolittle Walcott, who first described it, compared it to the a group of ocean-dwelling worms that are fierce predators, equipped with an array of spines on their head for grasping small prey - modern arrow worms (chaetognaths), but later scientists could not find evidence of the canonical grasping spines so they believed instead it might be a a ribbon worm, or its own distinct lineage only distantly related to anything that resembles it today.

read more

Amiskwia Sagittiformis: Weird Chimera Worm May Finally Get Its Place In The Tree Of Life published first on https://triviaqaweb.weebly.com/

[worldnewsbuz-blog]

Half-a-billion-year-old weird wonder worm finally gets its place in the tree of life -- ScienceDaily

Half-a-billion-year-old weird wonder worm finally gets its place in the tree of life — ScienceDaily

[ad_1]

Amiskwia was originally described by the famous palaeontologist Charles Doolittle Walcott (1850-1927) in 1911 who compared it to the modern arrow worms (chaetognaths) — a group of ocean-dwelling worms that are fierce predators, equipped with an array of spines on their head for grasping small prey.

Such organisms are found world-wide at sites like the famous Burgess Shale in the Canadian…

[m-asami]

倫理ツイート

@amiskwia: 倫理と物理的安全性を同一レイヤーで語って批判した気になるとか、考察レベルが低いとしか言いようがないです。 from http://twitter.com/amiskwia

[dinosaur-discourse]

Hi, what can you tell me about the wiggly jiggly Amiskwia?

Not much!

Amiskwia lived during the Middle Cambrian, about 520 million years ago.  It was a shell-less invertebrate, lacking any sort of support structure.  It had a roundish head with two tentacles, which might have been sensory antennae, and a long wormlike body lined with propulsive fins.  It was a powerful free swimmer that spent little, if any, time in benthic environments; as a result, fossilized remains are extremely rare.

Due to the rarity of fossil remains, Amiskwia is obscure and poorly understood, even for a Cambrian animal.  Numerous hypotheses have been put forward; it could be a basal chaeotognath, a nemertean, the larval form of some entirely different animal, or a member of a group with no living evolutionary descendants.

[palaeopedia]

The Amiskwia (1911)

Phylum : Incertae sedis Genus : Amiskwia Species : A. sagittiformis

Middle Cambrian (505 Ma)

3 cm long (size)

British Columbia Canada (map)

Amiskwia is a genus of large, soft-bodied invertebrate of unknown affinity known from fossils of the Middle Cambrian Lagerstätten both in the Burgess shale formation in British Columbia and the Maotianshan shales of Yunnan Province, China.

Very few specimens of this organism have been found, only eighteen of the Burgess shale species, A. sagittiformis, and a single specimen of the Maotianshan species, A. sinica — which may be a reflection of its genuine rarity, but is more likely to be due to taphonomic (preservational) or behavioural factors. The fossils reach 25 mm in length. The head is rounded, tipped with two tentacles, and appears to contain a four-ganglion brain; the body flattens out and broadens in the trunk, which appears to have been fairly muscular. Where the trunk meets the head there is a small tubular opening, which can be interpreted as the mouth; the gut terminates where the trunk narrows and meets the tail, which is broad and paddle shaped. The body morphology suggests a free energetic swimmer, which may be consistent with the dearth of fossils.

Amiskwia was originally categorized by paleontologist Charles Walcott. Walcott thought he saw three buccal spines in the fossils, and therefore categorized Amiskwia as a chaetognath worm (arrow worm). However, Amiskwia appears to lack the characteristic grasping spines and teeth of other Burgess fossil arrow worms. Later scientists suggested an affinity with the nemerteans (ribbon worms), but the evidence for this was somewhat inadequate. Conway Morris, on re-examining of the Burgess Shale fauna in the 1970s, described it as being the single known species in an otherwise unknown phylum, given that it has two tentacles near its mouth, rather than the characteristic single tentacle of true nemerteans. (Nemerteans do not have a single tentacle. However, a pair of antero-lateral tentacles is present in 2 of the many genera of pelagic nemerteans. Nemerteans do have a single eversible - normally internal - proboscis, which when everted could resemble an anterior median tentacle if fossilized. Whether retracted or everted, the proboscis is the only structure in pelagic nemerteans likely to fossilize, as it is the only structure with substantial connective tissue and muscle. The body wall has almost no muscle or connective tissue and is exceedingly unlikely to fossilize; hence, a pelagic nemertean fossil would be only the proboscis). Butterfield implies from the appearance of the fossils that the organisms may have lacked a cuticle: whilst this is also true of the nemerteans, these organisms lack a coelom and are thus unlikely to fossilise. He goes on to argue that the absence of cuticle is characteristic of the Chaetognaths; whilst teeth would be expected, a similar fossil, Wiwaxia, only shows such structures in 10% of the expected instances, and Anamolocarids are often found detached from their mouthparts, so the absence may be taphonomic rather than genuine. The absence of spines could simply mean that the fossils represent young organisms — or that later chaetognath evolution involved paedomorphosis.

[aquaticpaleo]

[alphynix]

Unsolved Paleo Mysteries Month #10 -- Ambiguous Amiskwia

Amiskwia was a tiny soft-bodied creature from the Middle Cambrian, known from a fairly small number of fossils -- about 18 specimens from the Burgess Shale in Canada (505 mya) and an additional one from the Maotianshan Shales in China (515 mya).

Despite only measuring about 2.5cm long (1”), it was one of the larger animals alive at the time. Its body features a head with two tentacles and a small mouth, a pair of stubby fins, and a flattened paddle-shaped tail, suggesting it was an active swimmer. Its internal anatomy has been well-preserved in some specimens, revealing a brain, gut, and traces of what may be blood vessels and a nerve cord.

But we don’t know what type of animal it is. At all.

It was initially thought to be an early arrow worm. However, fossils of Cambrian representatives of that group have since been found, and Amiskwia lacks their characteristic spines and teeth. A relationship to ribbon worms or molluscs has also been suggested, but these hypotheses have the same problems with missing key features.

So, for now, Amiskwia remains one of the “weird wonders” of the Cambrian Explosion with no obvious affinities to any other known group.

[EDIT: Amiskwia seems to have finally been identified as a gnathiferan!]

[alphynix]

@daalseth replied to your photo: Unsolved Paleo Mysteries Month #10 – Ambiguous...

Crazy blue sky idea: Suppose it was the immature form of Anomalcaris? Two appendages at the front. vestigial winglike structures. A larval form that hadn’t developed a hard shell yet.

A larval form of some other creature is another possibility!

Obviously without more information we can’t make a definite link to anything -- it could even be an as-yet-undiscovered animal -- but something like an anomalocarid is at least a very tempting speculative idea...

[alphynix]

April Fools 2017: Solved Paleo Mysteries Day

With Unsolved Mysteries Month over, and the first day of April upon us, it’s time for an important announcement: after many hours of grueling research, I’ve managed to solve every single one of the past month’s mysteries.

So, in no particular order:

Horse Snoots As we all know, weird noses are always trunks.

Ichthyoconodon There’s only one logical explanation.

Mosasaurs Mosasaurs were in fact the sister group to sauropodomorphs.

Amiskwia & Typhloesus Lichens.

Kakuru As recent discoveries like Deinocheirus and Spinosaurus have shown us, dinosaurs previously known only from fragmentary remains always turn out to be utterly ridiculous-looking and weirdly proportioned. Thus we have to go much much weirder to have a chance of ever predicting what Kakuru really looked like.

Paleodictyon DEEP SEA BEES

Godzillus An ancient kraken’s art project. It may have been a crude attempt at a self-portrait sculpture.

Trilobites Despite their apparent biological complexity, trilobites are really just naturally-occurring inorganic structures.

Diskagma Proterozoic macroviruses.

Acallosuchus Actually a giant tenrec.

Ammonites The lack of soft tissue is immediately explained if we reconsider ammonites as shelled ghosts. (Modern ghosts are of course secondarily shell-less.)

Chitinozoans Early skyfish eggs. Their disappearance from the marine fossil record marks not an extinction but their evolutionary transition to an entirely aerial lifestyle.

Maxberg Archaeopteryx While most specimens of Archaeopteryx are elaborate hoaxes, to the surprise of everyone the Maxberg specimen was actually a genuine fossil -- it just wasn’t a dinosaur. Further preparation of the slab after the casts were made found traces of the missing parts of its body, a discovery that had to be quickly covered up.

Pterosaurs Transitional pterosaurs went through a highly unusual “assisted flight” stage.

Vetulicolians The long sought-after transitional forms between crustaceans and fish.

Dinosaur Snoots Weird noses are ALWAYS trunks.

Permian Extinction “average extinction rate of 70% of all species” factoid actualy just statistical error. average extinction rate of 0% of all species. Lystrosaurus georg, who lives in early Triassic & displaces over 10,000 terrestrial vertebrates each day, is an outlier adn should not have been counted

Ediacarans The Ediacaran biota seems so strange and alien in comparison to all other known groups because they really weren’t related at all to any modern organisms. They were actually the very last native lifeforms of this planet, wiped out after the arrival of our invasive extraterrestrial ancestors.

Andrewsarchus Upon closer inspection of the nasal region of the skull, it turns out Andrewsarchus was a rhinogradentian.

Gluteus Preserved three-dimensional cross-sections of ancient extra-dimensional beings. Upper Devonian spacetime in Iowa was unusually “sticky”, trapping these odd manifestations within our universe.

Bats My own independent analysis recovers bats as highly modified armadillos. Also, through rigorous application of digital image enhancement, I have discovered many previously unseen anatomical features in photographs of fossil bats, and can now accurately reconstruct their ancestral form:

Amphicoelias Clearly no terrestrial animal could grow so huge and still be able to support its own weight. Sauropods that large would have inevitably begun to collapse under their own gravity, shedding most of their outer layers in a sudden explosion and scattering rare heavy elements around their immediate vicinity. (This is the primary reason we only find isolated bones of giant sauropods and no complete skeletons.)

The very largest individuals would also have occasionally become just massive enough to potentially collapse past their Schwarzschild radius and form an unstable saurosingularity -- which would have then violently evaporated via Hawking radiation with an energy output equivalent to a small comet impact.

And that’s why no animals get that big anymore.