Namapoikia
Encyclopedia
Namapoikia rietoogensis is among the earliest known animals to produce a calcareous
(probably aragonite
) skeleton.
Known from the Ediacaran
period, before the Cambrian explosion
of calcifying animals, the organism grew up to a metre in diameter and resembles a colonial sponge or cnidaria
n. It was an encruster, filling vertical fissures in the reef
s in which it originally grew.
The fossil was first found in the Omkyk Member from Rietoog in southern Namibia
, in association with another calcifying fossil, Cloudina
.
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
(probably aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...
) skeleton.
Known from the Ediacaran
Ediacaran
The Ediacaran Period , named after the Ediacara Hills of South Australia, is the last geological period of the Neoproterozoic Era and of the Proterozoic Eon, immediately preceding the Cambrian Period, the first period of the Paleozoic Era and of the Phanerozoic Eon...
period, before the Cambrian explosion
Cambrian explosion
The Cambrian explosion or Cambrian radiation was the relatively rapid appearance, around , of most major phyla, as demonstrated in the fossil record, accompanied by major diversification of other organisms, including animals, phytoplankton, and calcimicrobes...
of calcifying animals, the organism grew up to a metre in diameter and resembles a colonial sponge or cnidaria
Cnidaria
Cnidaria is a phylum containing over 9,000 species of animals found exclusively in aquatic and mostly marine environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance,...
n. It was an encruster, filling vertical fissures in the reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s in which it originally grew.
The fossil was first found in the Omkyk Member from Rietoog in southern Namibia
Namibia
Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...
, in association with another calcifying fossil, Cloudina
Cloudinid
The Cloudinids, an early metazoan family containing the genus Cloudina, lived in the late Ediacaran period and became extinct at the base of the Cambrian. They formed millimetre-scale conical fossils consisting of calcareous cones nested within one another; the appearance of the organism itself...
.
See also
- Ediacaran biota: life forms of the time
- Cloudina and NamacalathusNamacalathusNamacalathusNama, from the geological group where it was described, + Greek κάλαθος, kalathos, meaning "basket in the shape of a lily", or "wine goblet" is a problematic metazoan fossil occurring in the latest Ediacaran. The single species N...
, other calcifying Ediacaran fossils. - List of Ediacaran genera