genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
green algae
The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...
in the family Halimedaceae. Specimens have been found in
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...
to
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
beds in North America, Europe, and east Asia.
The alga is phylloid, meaning it has leaflike photosynthesizing structures called ''
thalli
Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were ...
'' (singular: ''thallus''). A thallus has the form of a broad, undulating blade, with circular to oval perforations scattered randomly across the blade. The blade consists of a fibrous medulla enclosed in a two-layered cortex. The thicker inner cortex consists of anastomosing utricles; that is, small sacklike structures joined by openings to their neighbors. The thin outer cortex consists of branchlets extending outwards from the inner cortex. Reproductive organs take the form of spherical protuberances within the inner cortex that are scattered irregularly over the surface of the thallus.
The alga is calcareous and its remains are important components of carbonate rock beds of
Pennsylvanian Pennsylvanian may refer to:
* A person or thing from Pennsylvania
* Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timesca ...
to
early Permian 01 or '01 may refer to:
* The year 2001, or any year ending with 01
* The month of January
* 1 (number)
Music
* '01 (Richard Müller album), 01'' (Richard Müller album), 2001
* 01 (Son of Dave album), ''01'' (Son of Dave album), 2000
* 01 (Urban ...
. It is particularly prominent as a carbonate producer (together with '' Paraepimastopora kansasensis'') in rocks of
Kasimovian
The Kasimovian is a geochronology, geochronologic age (geology), age or chronostratigraphy, chronostratigraphic stage (stratigraphy), stage in the International Commission on Stratigraphy, ICS geologic timescale. It is the third stage in the Penn ...
to
Gzhelian
The Gzhelian ( ) is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the youngest stage of the Pennsylvanian, the youngest subsystem of the Carboniferous. The Gzhelian lasted from to Ma. It follows the Kasim ...
age, in regions of warm water notably close to glaciated continental areas. It grew below
wave base
The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. At water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion ab ...
, probably in protected shallow water, and grew to at least a few inches in height