Isocrania
Isocrania is an extinct genus of brachiopods found during the Upper Cretaceous. Early representatives were attached to the underground, but later species are presumed to be free living at an increasingly earlier age. This was probably an adaptation to the increasing very thick and fine sedimentation during the latest Cretaceous.

Dwergenpaartje · CC BY-SA 3.0 · 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
- CraniidaePBDB
- Diet
- suspension feederPBDB, for Craniida
- Life habit
- epifaunalPBDB, for Craniida
- Motility
- stationaryPBDB, for Craniida
- Vision
- blindPBDB, for Craniata
- Environment
- marinePBDB, for Craniata
Time the record covers
At least 209 million years on record.
The record covers at least 247 Mya to 37.71 Mya. No occurrence read is dated outside 248.6 Mya to 33.9 Mya.
85 occurrences of Isocrania on record, most of them in the Late Cretaceous. 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
85 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
9 formations
- Ciply-Malogne Phosphatic Chalk Formation20
- Craie de Villedieu Formation1
- Santee Formation1
- Santee Limestone Formation1
- Tupelo Bay Formation1
- Obourg Formation1
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The named rock units Isocrania has been recovered from, largest first. Drawn where the rock is now, not where it formed. 57 occurrences have no formation on record, which is common for older literature.
Isocrania and its relatives
Late CretaceousWhere Isocrania and its relatives were recorded in the Late Cretaceous.
Found in the same rock
351 taxa- Terebratulina chrysalis39 sites
- Leptothyrellopsis polonicus24 sites
- Argyrotheca bronnii16 sites
- Rhynchonella16 sites
- Terebratulina faujasii16 sites
- Argyrotheca stevensis15 sites
- Kingena pentangulata15 sites
- Magas chitoniformis15 sites
- Argyrotheca popielae14 sites
- Cretirhynchia14 sites
- Terebratulina gracilis14 sites
- Aemula inusitata13 sites
- Argyrotheca13 sites
- Rugia curvirostris12 sites
- Carneithyris subcardinalis11 sites
- Rugia11 sites
- Rugia tenuicostata11 sites
- Terebratulina longicollis11 sites
- Argyrotheca coniuncta9 sites
- Argyrotheca hirundo9 sites
- Cryptopora9 sites
- Gwyniella9 sites
- Terebratulina rigida9 sites
- Crania8 sites
The Paleobiology Database records 66 sites for Isocrania, 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- End-Cretaceous brachiopod extinctions in the chalk of Denmark30
- Maastrichtian brachiopods from Ciply: palaeoecological and stratigraphical significance20
- Brachiopods and the stratigraphy of the Upper Campanian and Lower Maastrichtian Chalk of Norfolk, England12
- Brachiopodes du Campanien-Maastrichtien à Tercis les Bains (Landes, France)10
- Some Tertiary Brachiopods of the East Coast of the United States3
- Upper Campanian brachiopods from the Mons Basin (Hainaut, Belgium): the brachiopod assemblage from the Belemnitella mucronata Zone2
- Brachiopods from the Upper Cretaceous chalk of Mielnik (eastern Poland)2
- A Highly Diverse Olenekian Brachiopod Fauna from the Nanpanjiang Basin, South China, and Its Implications for the Early Triassic Biotic Recovery1
- Morphological adaptations of the brachiopods from a Late Cretaceous rocky shore, Ivö Klack, southern Sweden1
- Die Oberkreide des Kristianstad-Gebietes im südlichen Schweden1
- Winzig, aber sensationell! Meine kleinste Fosilfundstelle.1
- Type specimens of Maastrichtian fossils in the National Museum of Natural History, Leiden1
Each of the 85 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 Isocrania
- Source
- Wikipedia/Commons
- Credit
- Dwergenpaartje
- Licence
- CC BY-SA 3.0
- Commercial use
- the licence allows it
No 3D scan of Isocrania was found in MorphoSource and Sketchfab.
Smithsonian Open Access was 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, “Isocrania”
- 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 itCraniidae through timeFormations of the Late CretaceousThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Jaekel 1902