Aglaspidida
Aglaspidida is an extinct order of marine arthropods known from fossils spanning the Middle Cambrian to the Upper Ordovician. Initially considered chelicerates, modern anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within this group, and that they lie instead within the Artiopoda, thus placing them closer to the trilobites, being placed in the artiopod subgroup Vicissicaudata.

Junnn11 · CC BY-SA 4.0 · 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
- VicissicaudataPBDB
- Diet
- carnivorePBDB
- Life habit
- nektobenthicPBDB
- Motility
- actively mobilePBDB
- Vision
- well-developedPBDB
Time the record covers
At least 66 million years on record.
The record covers at least 516 Mya to 449.5 Mya. No occurrence read is dated outside 521 Mya to 445.2 Mya.
52 occurrences of Aglaspidida on record, most of them in the Cambrian. The Paleobiology Database records this as a living group, and the chart stops with its fossils rather than at the present. 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
52 occurrences- Cambrian81%
- Ordovician19%
These 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
21 formations
- St. Lawrence Formation16
- Weeks Formation5
- Emigrant Formation4
- Sandu Formation3
- Mickwitzia Sandstone Formation2
- Snegurovka Formation2
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The named rock units Aglaspidida has been recovered from, largest first. Drawn where the rock is now, not where it formed. 2 occurrences have no formation on record, which is common for older literature.
Aglaspidida and its relatives
CambrianWhere Aglaspidida and its relatives were recorded in the Cambrian.
Found in the same rock
408 taxa- Anatolepis heintzi5 sites
- Brachiopoda5 sites
- Lingulella5 sites
- Cruziana4 sites
- Hazelia4 sites
- Paleomerus4 sites
- Problematica4 sites
- Quasimodaspis brentsae4 sites
- Rusophycus4 sites
- Selkirkia4 sites
- Aglaspis3 sites
- Branchiocaris3 sites
- Crumillospongia3 sites
- Diplocraterion3 sites
- Glypharthrus thomasi3 sites
- Isoxys3 sites
- Leptomitus3 sites
- Mickwitzia monilifera3 sites
- Mickwitzia pretiosa3 sites
- Mobergella3 sites
- Naraoia3 sites
- Priapulida3 sites
- Primicaris3 sites
- Protolyellia3 sites
The Paleobiology Database records 34 sites for Aglaspidida, 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
22 references- Aglaspidida (Arthropoda) from the Upper Cambrian of Wisconsin16
- The diverse radiodont fauna from the Marjum Formation of Utah, USA (Cambrian: Drumian)4
- Non-trilobite arthropods from the Silver Peak Range, Nevada4
- The Vicissicaudata revisited – insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China3
- Predation by early Cambrian trilobites on infaunal worms - evidence from the Swedish Mickwitzia Sandstone3
- Fuping Fauna: A deep-water fauna in the prime of the Great Ordovician Biodiversification Event2
- Community palaeoecology of the early Cambrian Maotianshan Shale biota: Ecological dominance of priapulid worms2
- Probable Microvertebrates, Vertebrate-like Fossils, and Weird Things from the Wisconsin Ordovician2
- An early Ordovician vertebrate2
- Cambrian arthropods of the Maritime Territory2
- Exceptionally-preserved late Cambrian fossils from the McKay Group (British Columbia, Canada) and the evolution of tagmosis in aglaspidid arthropods1
- A three-dimensionally preserved aglaspidid euarthropod with a calcitic cuticle from the Ordovician of China1
Each of the 52 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. 10 further references are 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 Aglaspidida
- Source
- Wikipedia/Commons
- Credit
- Junnn11
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it
No 3D scan of Aglaspidida 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, “Aglaspidida”
- 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 itVicissicaudata through timeFormations of the CambrianThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Raasch 1939