Acutiramus
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. Eight species have been described, five from North America and two from the Czech Republic. The generic name derives from Latin acuto and Latin ramus ("branch"), referring to the acute angle of the final tooth of the claws relative to the rest of the claw.

John Mason Clarke (1857-1925) and Rudolf Ruedemann (1864-1956) · Public Domain · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.
On record
Recorded, not inferred- Sits inside
- PterygotidaePBDB
- Diet
- carnivorePBDB, for Eurypterida
- Life habit
- nektobenthicPBDB, for Eurypterida
- Motility
- actively mobilePBDB, for Eurypterida
- Vision
- well-developedPBDB, for Eurypterida
Time the record covers
At least 9.6 million years on record.
The record covers at least 422.7 Mya to 413.02 Mya. No occurrence read is dated outside 425 Mya to 382.31 Mya.
32 occurrences of Acutiramus on record, most of them in the Silurian. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.
When
32 occurrencesThese are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.
Found in
13 formations
- Pozary Formation8
- Lochkov Formation5
- Fiddlers Green Formation · Bertie Group3
- Bertie Formation3
- Cunningham Creek Formation · Mascarene Group2
- Olorda Formation2
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The named rock units Acutiramus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 1 occurrence has no formation on record, which is common for older literature.
Acutiramus and its relatives
SilurianWhere Acutiramus and its relatives were recorded in the Silurian.
Found in the same rock
325 taxa- Cephalopoda8 sites
- Scyphocrinites7 sites
- Bivalvia6 sites
- Ceratiocaris bohemica6 sites
- Conoparia novaki6 sites
- Howellella6 sites
- Ceratocephala5 sites
- Corbuloceras5 sites
- Gastropoda5 sites
- Leonaspis lochkovensis5 sites
- Monograptus5 sites
- Orbiculoidea5 sites
- Orthonychia elegans5 sites
- Parakionoceras originale5 sites
- Phyllocarida5 sites
- Praecardium5 sites
- Pterinopecten5 sites
- Pterygotus barrandei5 sites
- Actinopteria4 sites
- Areostrophia4 sites
- Boucia4 sites
- Cardiolinka4 sites
- Cooksonia4 sites
- Denckmannites miser4 sites
The Paleobiology Database records 24 sites for Acutiramus, and this reads all of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.
This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.
Entered from
13 references- Habitat of Llandoverian-Lochkovian eurypterids7
- Geology of the Barrandian: A Field Trip Guide. Senckenberg-Buchen, Frankfurt5
- Pterygotid eurypterids (Arthropoda, Chelicerata) in the Silurian and Devonian of Bohemia4
- Silurian field excursions: Prague Basin (Barrandian), Bohemia4
- Stratigraphy of Upper Silurian Cayugan Evaporites3
- Early Devonian eurypterids with Bohemian affinities from Catalonia (NE Spain)2
- Re-evaluating evidence of Australian eurypterids1
- A partial articulated acanthodian from the Silurian of New Brunswick, Canada1
- The presumed Synziphosuran Bunodella horrida Matthew, 1889 (Silurian; Cunningham Creek Formation, New Brunswick, Canada) is a eurypterid1
- Eurypterid horizons and the stratigraphy of Upper Silurian and Lower Devonian rocks of central-eastern New York State1
- Barrandian1
- Nouvelles connaissances acquises sur les limites des systemes Silurien et Devonien au Sahara Algerien1
Each of the 32 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. 1 further reference is not listed. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.
Media and terms
Media content1
Picture of Acutiramus
- Source
- Wikipedia/Commons
- Credit
- John Mason Clarke (1857-1925) and Rudolf Ruedemann (1864-1956)
- Licence
- Public Domain
- Commercial use
- the licence allows it
No 3D scan of Acutiramus was found in Sketchfab.
Smithsonian Open Access and MorphoSource were not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- Source
- Wikipedia, “Acutiramus”
- Licence
- CC BY-SA 4.0
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itPterygotidae through timeFormations of the SilurianThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. (Ruedemann 1935)