Borealosuchus
Borealosuchus is an extinct genus of crocodyliforms that lived from the Late Cretaceous to the Eocene in North America. It was named by Christopher Brochu in 1997 for several species that had been assigned to Leidyosuchus. The species assigned to it are: B. sternbergii, the type species, from the Maastrichtian of Colorado, Montana, North Dakota, South Dakota, and Wyoming; B. acutidentatus, from the Paleocene of Saskatchewan; B. formidabilis, from the Paleocene of North Dakota; B. griffithi, from the Paleocene of Alberta; and B. wilsoni, from the Eocene of Wyoming. B. formidabilis is particularly well-known, represented by the remains of many individuals from the Wannagan Creek site in North Dakota. An indeterminate species is known from the Late Cretaceous Demopolis Chalk in Alabama.

Dr.JExplorer · 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
- CrocodyliaPBDB
- Diet
- carnivorePBDB, for Crocodylia
- Motility
- actively mobilePBDB, for Osteichthyes
- Environment
- marinePBDB, for Mesoeucrocodylia
Time the record covers
At least 34 million years on record.
The record covers at least 72.2 Mya to 37.71 Mya. No occurrence read is dated outside 83.6 Mya to 33.9 Mya.
135 occurrences of Borealosuchus 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
135 occurrences- Late Cretaceous64%
- Paleocene27%
- Eocene9%
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
24 formations
- Hell Creek Formation · Montana Group55
- Lance Formation20
- Fort Union Formation14
- Denver Formation10
- Bridger Formation4
- Willwood Formation3
Loading coastlines…
The named rock units Borealosuchus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 3 occurrences have no formation on record, which is common for older literature.
Borealosuchus and its relatives
Late CretaceousWhere Borealosuchus and its relatives were recorded in the Late Cretaceous.
Found in the same rock
747 taxa- Brachychampsa montana61 sites
- Lepisosteus occidentalis57 sites
- Trionychidae55 sites
- Myledaphus bipartitus49 sites
- Scapherpeton tectum43 sites
- Champsosaurus42 sites
- Cyclurus fragosus39 sites
- Ceratopsidae38 sites
- Compsemys victa37 sites
- Lonchidion selachos33 sites
- Baenidae30 sites
- Adocus29 sites
- Paronychodon29 sites
- Meniscoessus robustus28 sites
- Opisthotriton kayi26 sites
- Cimolodon nitidus25 sites
- Tyrannosaurus rex25 sites
- Chelydridae24 sites
- Hadrosaurinae24 sites
- Theropoda24 sites
- Helopanoplia beecheri23 sites
- Melvius thomasi23 sites
- Richardoestesia isosceles22 sites
- Habrosaurus dilatus21 sites
The Paleobiology Database records 133 sites for Borealosuchus, 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
37 references- Vertebrate biostratigraphy of the Hell Creek Formation in southwestern North Dakota and northwestern South Dakota30
- A transitional Paleocene-Eocene reptile fauna from the Bighorn Basin, Wyoming16
- Fossil Vertebrate Collections15
- Fossil vertebrates from the Late Cretaceous Lance Formation, eastern Wyoming15
- First record of Borealosuchus sternbergii from the lower Paleocene Denver Formation (lower Danian), Colorado (Denver Basin)10
- Early Eocene fossil vertebrates from the southwestern Green River Basin, Lincoln and Uinta counties, Wyoming5
- A Late Cretaceous dinosaur and reptile assemblage from South Carolina, USA4
- Leidyosuchus sternbergii, a new species of crocodile from the Ceratops Beds of Wyoming3
- The Northern Crocodile: first report of Borealosuchus (Eusuchia; Crocodylia) from Saskatchewan’s lower Ravenscrag Formation (earliest Paleocene) with implications for biogeography2
- Amphibian, reptilian, and avian remains from the Fox Hills Formation (Maastrichtian): shoreline and estuarine deposits of the Pierre Sea in south-central North Dakota2
- Turtle diversity and abundance through the lower Eocene Willwood Formation of the southern Bighorn Basin2
- Borealosuchus (Crocodylia) from the Paleocene of Big Bend National Park, Texas2
Each of the 135 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. 25 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 content4
Picture of Borealosuchus
- Source
- Wikipedia/Commons
- Credit
- Dr.JExplorer
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it
3D scan
- Source
- Smithsonian
- Licence
- CC0 — this site’s default, not the record’s
- Commercial use
- the licence allows it
- Specimen
- Borealosuchus sternbergii (Gilmore, 1910)

CT scan
- Source
- MorphoSource
- Licence
- not stated by the source
- Commercial use
- cannot be read from the licence given — check the record
- Specimen
- Borealosuchus sternbergii · dmns:epv:136252
3D model
- Source
- Sketchfab
- Licence
- CC Attribution-NonCommercial
- Commercial use
- the licence does not allow it
The description on this site
- 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 itCrocodylia through timeFormations of the Late CretaceousThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Brochu 1997