Palaeophragmodictya

Taxobox
fossil_range=Late Ediacaran, Fossil range|558|555
regnum = Animalia
genus="Palaeophragmodictya"
genus_authority = GEhling & Rigby 1996
species="P. reticulata"

"Palaeophragmodictya" is a Precambrian sponge-grade organism.Originally interpreted as a hexactinellid sponge,citation
author = Gehling, J. G.; Rigby, J. K.
year = 1996
journal = Journal of Paleontology
volume = 70
issue = 2
pages = 185–195
title = Long expected sponges from theNeoproterozoic Ediacara fauna of South Australia
url = http://links.jstor.org/sici?sici=0022-3360(199603)70%3A2%3C185%3ALESFTN%3E2.0.CO%3B2-A
publisher = JSTOR] the organism also bears some coelomate characteristics, including bilateral symmetry.citation
author = Serezhnikova, E.
year = 2007
title = "Palaeophragmodictya spinosa" sp. Nov., a bilateral benthic organism from the Vendian of the Southeastern White Sea Region
journal = Paleontological Journal
volume = 41
issue = 4
pages = 360–369
doi = 10.1134/S0031030107040028
url = http://www.maik.ru/cgi-perl/search.pl?type=abstract] Citation
author = Botting, J. P.
year = 2007
volume = 40
title="Cambrian" demosponges in the Ordovician of Morocco: Insights into the early evolutionary history of …
journal = Geobios
issue = 6
pages = 737–748]

Morphology

The organisms take the form of a round bag, 7–68 mm in diameter, with an uneven margin. Radial grooves define sac-like compartments within the bag. The radial pattern has an element of bilateral symmetry. A stalk emerges from the central point of some specimens, at the top of the organism; in life, it probably extended into the water column. Ray-like filaments radiate outwards from the edge of the bag. Some structures in the organism have been interpreted as spicules.citation
author = Ivantsov, A. Y.; Malakhovskaya, Y. E.; Serezhnikova, E. A.
year = 2004
journal = Paleontological Journal
volume = 38
issue = 1
pages = 1–9
title = Some Problematic Fossils from the Vendian of the Southeastern White Sea Region
url = http://vend.paleo.ru/pub/Ivantsov_et_al_2004_eng.pdf]

Ecology

The organisms have been interpreted as tall suspension feeders, reaching 10cm or more up into the sea water above them.citation
author = Yuan, X.; Xiao, S.; Parsley, R. L.; Zhou, C.; Chen, Z.; Hu, J.
year = 2002
title = Towering sponges in an Early Cambrian Lagerstätte: Disparity between nonbilaterian and bilaterian epifaunal tierers at the Neoproterozoic-Cambrian transition
journal = Geology
volume = 30
issue = 4
pages = 363–366
doi = 10.1130/0091-7613(2002)030<0363:TSIAEC>2.0.CO;2
url = http://geology.geoscienceworld.org/cgi/content/abstract/30/4/363]

Original description

The genus was originally considered to be a member of the Dictyospongiidae family (hexactinellia), and was among the first Precambrian sponges to be described.

Distribution

First found in the Pound group of Australia, fossils have also been recovered from the White Sea region of Russia.

ee also

*"Fedomia", another sponge-grade Ediacaran organism
*"Inaria", an Ediacaran with a similar form

References