''Pambikalbae'' is a

monospecific In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus known from the

Ediacaran The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and th ...

Period (approximately 555 million years ago) of South Australia. Its morphology resembles the morphology of colonial

cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that th ...

ns, such as

sea pen Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 14 families within the order; 35 extant genera, and it is estimated that of 450 described species, around 200 are valid. Sea pens have a cosmo ...

s or

siphonophore Siphonophorae (from Greek ''siphōn'' 'tube' + ''pherein'' 'to bear') is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 specie ...

Description

''Pambikalbae'' had a broad,

frondose Frondosity (from Latin ''frondōsus'' meaning 'leafy') is the property of an organism that normally flourishes with fronds or leaf-like structures. Many frondose organisms are thalloid and lack the organization of tissues into organs, with the ...

-shaped body composed of multiple vanes extending from an axial stem, and containing a serial series of chambers. Specimens of ''Pambikalbae'' found thus far have measured approximately 20 to 30 cm in length, with a width of 12 cm at the widest point of the frondose-body, and 6.6 cm wide at the stem.

Diversity

''Pambikalbae'' is a monospecific genus, with only one known species, ''Pambikalbae hasenohrae''.

Discovery

''Pambikalbae hasenohrae'' was discovered within a fossiliferous exposure on the Nilpena pastoral property in the Flinders Ranges in South Australia. Pamela Hasenohr, an amateur geologist, found and brought the ''Pambikalbae'' fossils to the attention of Richard Jenkins, a research associate of the

South Australian Museum The South Australian Museum is a natural history museum and research institution in Adelaide, South Australia, founded in 1856 and owned by the Government of South Australia. It occupies a complex of buildings on North Terrace in the cultu ...

. Richard Jenkins and his associate Chris Nedin collected five ''Pambikalbae'' specimens from this exposure, and published their description of the genus in 2007. In this publication, they named the type species of the genus, ''P. hasenohrae,'' after Pamela Hasenohr.

Distribution

''Pambikalbae hasenohrae'' specimens have been found preserved in channel sandstones on the Nilpena pastoral property in the Flinders Ranges of South Australia. These sandstones occur directly below the Ediacaran Member of the Rawnsley Quartzite, a stratigraphic layer rich with Ediacaran fossils that was deposited during cycles of marine transgression.

Taphonomy

''Pambikalbae hasenohrae'' fossils consist of both surface molds and internal casts. It is likely that the hollow chambers of these specimens were partly filled with sediments before their entire bodies were buried, preventing the bodies from being entirely flattened during burial and preserving the three-dimensional structure of both the internal and external parts of the original organisms. The lithified sands that occupy the once hollow parts of the specimens exhibit fine laminations and small scale crossbedding, which indicates that the specimens were buried progressively, not instantly. This gradual burial may have created enough time for currents to carry sediments into the internal chambers before the entire organism was buried.

Ecology

''Pambikalbae'' was likely a benthic, sessile, heterotrophic marine suspension feeder. The chambers of ''Pambikalbae'' were open to the external environment, allowing water to enter and exit freely. These chambers were likely lined with flagellate cells or cilia, which would capture detrital food particles suspended in the water.

References

{{Taxonbar, from=Q49002437 Ediacaran life Siphonophorae Prehistoric cnidarians Petalonamae