Branchioplax washingtoniana
Branchioplax is an extinct genus of crab which existed in Alaska and Washington during the Eocene period. It was first named by Mary Rathbun in 1916, and contains ten species, including Branchioplax washingtoniana from the Hoko River Formation, Branchioplax carmanahensis, and Branchioplax ballingi.

Kevmin · 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
- BranchioplaxPBDB
- Diet
- carnivorePBDB, for Decapoda
- Life habit
- infaunalPBDB, for Mathildellidae
- Motility
- actively mobilePBDB, for Malacostraca
- Vision
- well-developedPBDB, for Malacostraca
Time the record covers
At least 14 million years on record.
The record covers at least 48.07 Mya to 33.9 Mya. No occurrence read is dated outside 61.66 Mya to 5.333 Mya.
16 occurrences of Branchioplax washingtoniana on record, most of them in the Eocene. 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
16 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
5 formations
Loading coastlines…
The named rock units Branchioplax washingtoniana has been recovered from, largest first. Drawn where the rock is now, not where it formed. 8 occurrences have no formation on record, which is common for older literature.
Branchioplax washingtoniana and its relatives
EoceneWhere Branchioplax washingtoniana and its relatives were recorded in the Eocene.
Found in the same rock
23 taxa- Raninoides vaderensis3 sites
- Macroacaena alseanus2 sites
- Alcespina americana1 site
- Anisospinos berglundi1 site
- Brecanclawu rathbunae1 site
- Callianopsis inornatus1 site
- Carinaranina marionae1 site
- Carpilius occidentalis1 site
- Ctenocheles hokoensis1 site
- Eutrephoceras eyerdami1 site
- Glyphea micheleae1 site
- Laeviranina goedertorum1 site
- Mursia aspina1 site
- Paguristes hokoensis1 site
- Palaeopinnixa rathbunae1 site
- Portunites1 site
- Portunites macrospinus1 site
- Portunites nodosa1 site
- Pulalius dunhamorum1 site
- Pulalius vulgaris1 site
- Raninoides fulgidus1 site
- Rimella elongata1 site
- Rimella supraplicata1 site
The Paleobiology Database records 8 sites for Branchioplax washingtoniana, and this reads all of them. The number is how many of those sites it was catalogued from too.
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
6 references- The fossil stalk-eyed Crustacea of the Pacific slope of North America8
- Eocene decapod crustaceans from Pulali Point, Washington2
- Tertiary Crustaceans: Collecting localities in western Washington State2
- Fossil Decapod Crustaceans from the Lower Tertiary of the Prince Willam Sound Region, Gulf of Alaska2
- Inferences for grooming behavior drawn from epibionts on early to middle Cenozoic crabs of Oregon and Washington state, USA1
- Additions to the Tertiary decapod fauna of the Pacific Northwest of North America1
Each of the 16 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. 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 content2
Picture of Branchioplax washingtoniana
- Source
- Wikipedia/Commons
- Credit
- Kevmin
- Licence
- CC BY-SA 3.0
- 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
- Branchioplax washingtoniana Rathbun
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 itBranchioplax through timeFormations of the EoceneThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Rathbun 1916