Namalia Temporal range: Ediacaran | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | incertae sedis |
Genus: | † Namalia Germs, 1968 |
Species: | †N. villieriensis |
Binomial name | |
†Namalia villieriensis Germs, 1968 | |
Namalia villieriensis was first described in 1968 by G. J. B. Germs from an outcrop near Helmeringhausen, Namibia and dates back to the Ediacaran Period, around 548 - 541 Ma. Namalia has a conical structure and it is thought that it lived semi-buried in sediment along the seafloor.
The holotype fossil of Namalia was found at the Buchholzbrunn member, Dabis Formation, Kuibis Subgroup, Nama Group, Namibia in 1963 by G. J. B. Germs in an orthoquartzite layer, and officially described by them in 1968. [1]
The generic name Namalia derives from the place name "Nama Group", which the fossils were found in.
Namalia is described as a multi-layered conical fossil, 52–90 mm (2.0–3.5 in) in length, that exhibits 27–40 longitudinally corrugated ridges on the outer surface with a blunt apex. [2] In cross section, this genus has a 15–70 mm (0.6–2.8 in) oval opening with two layers and septa in between them. [3] Many specimens are deformed indicating that the body was probably soft. [3]
A recent paper that describes Arimasia , also re-evaluated all genera from the same area that Arimasia comes from, noting that Namalia may be a senior synonym of Kuibisia, with both possibly being conspecific with the Ernietta genus all together, noting that the differences in morphology may be down to the preservation of the fossil material. [4]
Only one species, Namalia villieriensis, has been discovered so far. [1] But there are multiple other known Nama-type biota, or benthic organisms with the hard parts preserved, that are thought to have lived in similar ecological niches as N. villieriensis. [5]
Namalia lived in colonies as well as scattered individuals and are interpreted to have occupied shallow to deep waters. [3] The specimens are found filled with sand which was previously thought to have entered the quilts (skeletal structure) after death. [5] The taphonomic scenario is still debated as this scenario leads to a mechanical problem in hydrostatically supported structures. [5] The prevailing hypothesis is that the sand was already in the quilt and that it could have loosely attached to trabecular structures that then disintegrated after death, or that the sand grains may have floated in the protoplasm. [5]
Namalia has only ever been found at one other locality besides the orthoquartzite in the Kuibis Series in Namibia. [2] The only other discovered site is located in the June beds in the Sewki Brook Formation in the Mackenzie Mountains in northwest Canada. [2]
The cloudinids, an early metazoan family containing the genera Acuticocloudina, Cloudina and Conotubus, lived in the late Ediacaran period about 550 million years ago 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 remains unknown. The name Cloudina honors the 20th-century geologist and paleontologist Preston Cloud.
Archaeocyatha is a taxon of extinct, sessile, reef-building marine sponges that lived in warm tropical and subtropical waters during the Cambrian Period. It is believed that the centre of the Archaeocyatha origin is now located in East Siberia, where they are first known from the beginning of the Tommotian Age of the Cambrian, 525 million years ago (mya). In other regions of the world, they appeared much later, during the Atdabanian, and quickly diversified into over a hundred families.
Dickinsonia is a genus of extinct organism, most likely an animal, that lived during the late Ediacaran period in what is now Australia, China, Russia, and Ukraine. It is one of the best known members of the Ediacaran biota. The individual Dickinsonia typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth has been considered consistent with a stem-group bilaterian affinity, though various other affinities have been proposed. It lived during the late Ediacaran. The discovery of cholesterol molecules in fossils of Dickinsonia lends support to the idea that Dickinsonia was an animal, though these results have been questioned.
Ausia fenestrata is a curious Ediacaran period fossil represented by only one specimen 5 cm long from the Nama Group, a Vendian to Cambrian group of stratigraphic sequences deposited in the Nama foreland basin in central and southern Namibia. It has similarity to Burykhia from Ediacaran (Vendian) siliciclastic sediments exposed on the Syuzma River of Arkhangelsk Oblast, northwest Russia. This fossil is of the form of an elongate bag-like sandstone cast tapering to a cone on one end. The surface of the fossil is covered with oval depressions ("windows") regularly spaced over the surface in the manner of concentric/parallel rows. The taxonomic identity of Ausia is unresolved.
Charnia is an extinct genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture. The genus Charnia was named after Charnwood Forest in Leicestershire, England, where the first fossilised specimen was found; the species name after Roger Mason, a schoolboy who found it. Charnia is significant because it was the first Precambrian fossil to be recognized as such.
Hiemalora is a fossil of the Ediacaran biota, reaching around 3 cm in diameter, which superficially resembles a sea anemone. The genus has a sack-like body with faint radiating lines originally interpreted as tentacles, but discovery of a frond-like structure seemingly attached to some Heimalora has added weight to a competing interpretation: that it represents the holdfast of a larger organism.
Rangea is a frond-like Ediacaran fossil with six-fold radial symmetry. It is the type genus of the rangeomorphs.
Namacalathus is a problematic metazoan fossil occurring in the latest Ediacaran. The first, and only described species, N. hermanastes, was first described in 2000 from the Nama Group of central and southern Namibia.
Swartpuntia is a monospecific genus of erniettomorph from the terminal Ediacaran period, with at least three quilted, leaf-shaped petaloids — probably five or six. The petaloids comprise vertical sheets of tubes filled with sand. Swartpuntia specimens range in length from 12 to 19 cm, and in width from 11.5 to 140 cm. The margin is serrated, with a 1 mm wide groove. A 14 mm wide stem extends down the middle, tapering towards the top, and stopping 25 mm from the tip. The stem has a V-shaped ornamentation on it. The original fossils were found at, and named after, the Swartpunt farm between Aus and Rosh Pinah in Namibia. The generic name comes from Swartpunt, meaning black point in reference to the colour of the rocks. The specific name germsi honours Gerard Germs, who studied the Nama formation of geological beds.
The Ediacaranbiota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period. These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.
Conulariida are an extinct group of medusozoan cnidarians known from fossils spanning from the latest Ediacaran up until the Late Triassic. They are almost exclusively known from their hard external structures, which were pyramidal in shape and made up of numerous lamellae.
Ernietta is an extinct genus of Ediacaran organisms with an infaunal lifestyle. Fossil preservations and modeling indicate this organism was sessile and “sack”-shaped. It survived partly buried in substrate, with an upturned bell-shaped frill exposed above the sediment-water interface. Ernietta have been recovered from present-day Namibia, and are a part of the Ediacaran biota, a late Proterozoic radiation of multicellular organisms. They are among the earliest complex multicellular organisms and are known from the late Ediacaran. Ernietta plateauensis remains the sole species of the genus.
The small shelly fauna, small shelly fossils (SSF), or early skeletal fossils (ESF) are mineralized fossils, many only a few millimetres long, with a nearly continuous record from the latest stages of the Ediacaran to the end of the Early Cambrian Period. They are very diverse, and there is no formal definition of "small shelly fauna" or "small shelly fossils". Almost all are from earlier rocks than more familiar fossils such as trilobites. Since most SSFs were preserved by being covered quickly with phosphate and this method of preservation is mainly limited to the late Ediacaran and early Cambrian periods, the animals that made them may actually have arisen earlier and persisted after this time span.
Pelagiellidae is an extinct family of Paleozoic fossil 'snails'. Some material assigned to this taxon represents gastropod molluscs, but some chaeta-bearing specimens first assigned to Pelagiella are perhaps better interpreted as tube-bearing annelid worms.
The Nama Group is a 125,000 square kilometres (48,000 sq mi) megaregional Vendian to Cambrian group of stratigraphic sequences deposited in the Nama foreland basin in central and southern Namibia. The Nama Basin is a peripheral foreland basin, and the Nama Group was deposited in two early basins, the Zaris and Witputs, to the north, while the South African Vanrhynsdorp Group was deposited in the southern third. The Nama Group is made of fluvial and shallow-water marine sediments, both siliciclastic and carbonate. La Tinta Group in Argentina is considered equivalent to Nama Group.
Archaeichnium is a member of the Ediacaran biota first described by Martin Glaessner in 1963. It is characterized as a tubular fossil found in the Nama group of South West Africa.
Kuibisia glabra is a sac-like and polyp-like solitary Ediacaran organism. The fossil of Kuibisia was dated to be around 550 - 548 million years old and was found in a pteridinium deposit at Aar Farm in Namibia, South Africa.
Atakia is a genus of animals that were members of the Ediacaran fauna, which existed from 635 to 541 million years ago. Discovered in Ukraine in 1979 by Palij, the genus Atakia are soft-bodied Metazoan cast in Vendian sediments found on the Eastern European Platform formations. Oftentimes the genus Atakia is used as a comparison to other genera, because very little information is known about this genus. There is a discontinuity in identification because the genus Fustiglyphus Vialov is debated to be the same as Atakia but found in different regions.
Arimasia germsi is an extinct sponge from the late Ediacaran, with possible affinities to the Archaeocyatha. Estimated to be about 543 million years old, A. germsi has been identified as possibly being the oldest known archaeocyathan to date. Its fossil material was found between 1993 and 1996 from the Nama Group in Namibia.