#acutiramus
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friedmanlab.bsky.social
Variety pack of eurypterids at UMMNH for #FossilFriday: Acutiramus (UMMP IP 86635), Paracarcinosoma (UMMP IP 62598), Eurypterus (UMMP IP 7157), and Dolichopterus (UMMP IP 62680). All from the Silurian of New York and Ontario.
A fossil eurypterid on a gray slab of rock. A fossil eurypterid on a gray slab of rock. It has a narrow tail and a swollen midsection. A fossil eurypterid on a gray slab of rock next to a model of the same species painted green. A fossil eurypterid on a gray slab of rock with long, extended swimming appendages. It is displayed next to a model of the same species painted brown and yellow.
October 2, 2026 at 11:59 AM
jun075.bsky.social
Up-to-date life-sized Acutiramus!
friedmanlab.bsky.social Matt Friedman @friedmanlab.bsky.social · 5d
New exhibit at UMMNH. Come for the eurypterids, stay for the ostracoderms.
Image of a museum display featuring a large model of an aquatic arthropod. Close-up of part of museum display featuring casts and models of jawless fishes.
September 30, 2026 at 6:38 AM
amypteride.bsky.social
You know the drill, let's talk about its discovery, paleoenvironment, age and morphology first to meet this trigonotarbid.

#Cheliceratime
2/4
Bunaia woodwardi is an extinct basal chelicerate that was first named in 1919 after fossils found in Ontario rocks parts of the Bertie group, a large sequence of fossiliferous layers essentially made of limestone & dolomite. These rocks delivered dozens of silurian chelicerates from Eastern North America, especially eurypterids like Acutiramus & Pterygotus. The species was extensively re-studied and properly re-described in 2024 with the addition of new, more complete specimens whose preserved features allowed to investigate further details about its ventral anatomy. Bunaia woodwardi lived 422 to 419 million years ago, at the end of the Silurian Period. At that time, the lands that would become North America, then “Laurentia”, were in the Southern tropics and partially covered by shallow seas thanks to the warm climate of the Late Silurian. The Bertie Group preserved an epicontinental shallow marine environment near coastlines. B. woodwardi was one of the many animals thriving in such waters, alongside eurypterids, brachiopods & numerous mollusks. B. woodwardi was rather large for a basal chelicerate, reaching more than 3 cm in length. The rounded prosoma accounted for about 30% of total body length, and extended backwards on its sides with large genal spines. The opisthosoma was longer, comprising 11 segments in total, several of them extending on the sides thanks to lateral pleural spines. The telson is as of now unknown, but the opisthosoma bore a median ventral appendage similar to other stem chelicerates. Due to the mostly ventral preservation of the specimens known from this species, it’s been observed that its legs were biramous: instead of having only one clear identifiable walking part, biramous legs are made of an internal walking branch, and an external non-walking one often fluffy-looking. The opisthosomal appendages were flap-like, the first being significantly enlarged.
June 12, 2026 at 3:30 PM
friedmanlab.bsky.social
Amazing reconstruction of a famous eurypterid site! Here's one member of that fauna, Acutiramus macrophthalamus (UMMP IP 86635).
Fossil eurypterid preserved as black on gray matrix. Segments and a paddle-like tail are clearly visible, as is one of the large claws.
May 31, 2026 at 7:12 PM
joschuaknuppe.bsky.social
The most common large eurypterid from is Acutiramus, which might have been a largely nocturnal predator of softer prey. Interestingly no vertebrates have been described so far!
Size charts by @montanoceratops.bsky.social .
May 31, 2026 at 6:40 PM
joschuaknuppe.bsky.social
420 Million years before the reign of Mamdani, two Acutiramus wake up from their daylight slumber as thousands are Eurypterus begin to invade the shallow, warm waters of New York.
This is the Fiddlers Green or Bertie Formation, a Silurian lagerstätte known for its eurypterids🧵
May 31, 2026 at 6:40 PM
dreambob.bsky.social
23/05/2026
Acutiramus

{ #paleoart, #Sciart }
((Oppss I forgot to add the date and signature))
23/05/2026 Acutiramus "It's been one of those weeks. Pass the YURI" 23/05/2026 Acutiramus "It's been one of those weeks. Pass the YAOI"
May 23, 2026 at 10:15 AM
sheishine.bsky.social
Listed Ancient Sea Creature Diorama: Acutiramus print in my Etsy shop!

*Please note*
U.S. orders ship once a week on TUESDAYS due to limited access to a faraway drop-off location.

古代海洋生物ウミサソリ・ジオラマ・ポスター（ほぼA4）をEtsyショップに追加しました！

hine.etsy.com

#hinemizushima #etsy #print #paleoart #水島ひね
March 21, 2026 at 9:44 PM
tommyplodocus.bsky.social
A giant of the Silurian seas for this #FossilFriday!
Acutiramus macrophthalmus was a eurypterid that lived 421 million years ago. This example is made up of several specimens found at one site in New York, USA. These Paleozoic predators could reach 2 metres in length!
December 12, 2025 at 2:35 PM
cranialoraptor.bsky.social
後、久しぶりに見る標本がちらほらと。生命大躍進展から10年経つのに驚いたし、クリオロフォサウルスに至っては16年ぶり。
アノマロカリスAnomalocaris canadensis アクティラムスAcutiramus macrophthalmus レドンダサウルスRedondasaurus gregorii Cryolophosaurus ellioti
November 9, 2025 at 2:36 PM
hi-story.bsky.social
「Pterygotus」って知ってる？

実は、昔に生息していた巨大な海の生き物なんだって！ なんと、サソリの仲間で、長い腕と大きなはさみを持っていたんだってすん。 1872年にチェコで見つかった「P. nobilis」という種類は、はさみの歯の並びが他の「Pterygotus」とはちょっと違っていて、研究者たちは悩んでいたみたいなの。

今は別の仲間「Acutiramus bohemicus」と同じ種類だと考えられてるんだけど、見つかった化石が小さくて欠けているから、まだはっきりとはわからないんだってなのお。en.wikipedia.org #トリビア
November 4, 2025 at 4:12 PM
fossildetective.bsky.social
Happy #FlatFuckFriday to all who celebrate.
A very long, very flat model of the eurypterid Acutiramus at the Cincinnati Museum. A front view of the eurypterid, equally flat.
October 24, 2025 at 3:01 PM
veste.itch.io
I think I saw Godzilla fight this guy once
A statue of acutiramus macrophthalmus
September 19, 2025 at 7:03 PM
fossildetective.bsky.social
The pterygotid eurypterid Acutiramus for #FossilFriday. The specimen shows the swimming paddle in exquisite detail and also gives a good view of the enlarged eyes on the carapace. Collected from the Silurian of New York, the specimen is housed in the Yale Peabody Museum. ⚒️🧪
The head and upper body of a eurypterid. The head bears a pear of large oval eyes that are positioned at the margin and are about one third the size of the entire headshield. The paddles, which are the sixth pair of appendages, can be seen projecting back and to the side of the head. They preserve individual leg segments and small serrations around their margin.
June 6, 2025 at 3:57 PM
rua-lupa.bsky.social
I normally don't go for pool floaties, but I would get one of an Acutiramus - one of the largest eurypterids or sea scorpions, growing up to two metres in length. It lived during from the Late Silurian to the Early Devonian, 422 to 407 million years ago.

Artwork by Kawasaki Satoshi
Acutiramus was one of the largest eurypterids or sea scorpions, growing up to two metres in length. It lived during from the Late Silurian to the Early Devonian, 422 to 407 million years ago. Its serrated claws were used for catching live prey or tearing open carcasses on the sea floor. Artwork by Kawasaki Satoshi
February 27, 2025 at 2:51 PM
c0nc0rdance.bsky.social
Euryptids, or 'giant sea scorpions', were among the largest arthropods ever to have lived.

For ~200 million years (Silurian to Late Devonian), they scuttled at the bottoms of oceans, lakes & swamps. Then they disappeared & only their cousins, the horseshoe crabs, remember their passing.
Size comparison of six of the largest eurypterids (sea scorpions). They are (from largest to smallest): Pterygotus grandidentatus, Pentecopterus decorahensis, Acutiramus macrophthalmus, A. bohemicus, Carcinosoma punctatum, and Jaekelopterus rhenaniae. Source Images: Compiled from these three comparisons by myself: Pterygotus, Acutiramus, and Jaekelopterus Pentecopterus Carcinosoma CREDIT: Slate Weasel, Wikimedia
February 27, 2025 at 2:31 PM
sheishine.bsky.social
Listed a new print, Ancient Sea Creature Diorama: Acutiramus, on my @Etsy shop!

Etsyショップに新しい（ほぼA4）ポスター「古代海洋生物 アクチラムス ジオラマ」をアップしました。ウオを捕獲してるシルル紀のウミサソリです。

hine.etsy.com/listing/1843...

#水島ひね #hinemizushima #print #acutiramus #diorama #seascorpion #ancientseacreature #silurian #アクチラムス #古代海洋生物 #ジオラマ
January 14, 2025 at 11:22 PM
jopabinia.bsky.social
Better view here
Acutiramus macrophthalmus (Sea scorpion)
Eurypterids, sometimes known as sea scorpions, were predatory marine arthropods (joint-legged animals without a backbone) that lacked mineralized hard parts. The huge, …
collections.rom.on.ca
December 17, 2024 at 2:14 AM
tommyplodocus.bsky.social
Two giant pincers greet us behind Door #16 of the Fossil Advent Calendar! Acutiramus macrophthalmus was a eurypterid that could grow to over 2 metres long. It lived 421 million years ago during the Silurian Period and likely used its claws to capture prey! #AdventCalendar
December 16, 2024 at 1:45 PM
just9art.bsky.social
Old art, Acutiramus
October 18, 2024 at 1:28 PM
montanoceratops.bsky.social
As Above, So Below
I adore this slab with Eurypterus remipes and Acutiramus cummingsi from the ROM
October 9, 2024 at 6:27 PM
ashhiggins.bsky.social
“But what is she doing under there? 🤔”

“She’s a banana”
Acutiramus was one of the largest eurypterids or sea scorpions, growing up to two metres in length. It lived during from the Late Silurian to the Early Devonian, 422 to 407 million years ago. Its serrated claws were used for catching live prey or tearing open carcasses on the sea floor. Artwork by Kawasaki Satoshi Woman in a yellow two piece bathing suit lying underneath a very large scorpion like creature
May 22, 2024 at 4:19 PM
romanlandry.bsky.social
New #Silurian #Paleoart featuring #acutiramus #phragmoceras #nerepisacanthus #digitalart #procreate #ipadpro #eurypterid #paleozoic #phanerozoic
March 16, 2024 at 5:15 PM
fossildetective.bsky.social
For the penultimate #FossilFriday of the year, looking back at one of the best times this year with various eurypterids from the Royal Ontario Museum, some of the smallest and largest individuals in the collections. ⚒️🧪
A well-preserved Acutiramus on display in the museum. The fossil shows large eyes and a broad tail, with its body curved around like a shrimp. The animal couldn't bend like this in life, so the fossil is most likely that of a shed exoskeleton. A large metastoma - the plate found on the underside of the eurypterid's head behind the mouth. The fossil is an elongate oval with a notched anterior. My hand is shown alongside for scale, with the fossil being slightly larger. A small, relatively complete fossil of a Eurypterus. It preserves the underside and shows the large paddles and the oval metastoma behind the mouth. The entire individual fits well within my hand.
December 22, 2023 at 8:04 PM
fossildetective.bsky.social
Making very slow progress on the big project so this #FossilFriday I am still on pterygotids. While several classification schemes for the group have focused on their claws, others have looked at the genital appendages, like this one of Acutiramus. 🧪⚒️
A large fossil bearing large, dense curved scales with a diamond-shaped structure in the centre.
September 8, 2023 at 2:30 PM