''Tentaculites'' is an extinct genus of conical fossils of uncertain affinity, class
Tentaculita
Tentaculita is an extinct class of uncertain placement ranging from the Early Ordovician to the Middle Jurassic. They were suspension feeders with a near worldwide distribution. For a more thorough discussion, see '' Tentaculites''.
The presen ...
, although it is not the only member of the class. It is known from Lower Ordovician to Upper Devonian deposits both as calcitic shells with a brachiopod-like microstructure and carbonaceous 'linings'. The "tentaculites" (i.e. tentaculita) are also referred to as the styliolinids.
Affinity
The taxonomic classification of tentaculitids is uncertain. Some grouped them with pteropods, but there is no modern support and only superficial similarity. They may also be related to other conical shells of uncertain affinity including
cornulitids
Cornulitida is an extinct order of encrusting animals from class Tentaculita, which were common around the globe in the Ordovician to Devonian oceans, and survived until the Carboniferous.
The organisms had shells, and were subject to predation ...
, ''
Anticalyptraea
''Anticalyptraea'' is a fossil genus of encrusting tentaculitoid tubeworms from the Silurian to Devonian of Europe and North America (Vinn, 2010).
''Anticalyptraea'' commonly encrust various invertebrate fossils such as stromatoporoids, rugose ...
brachiopod
Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, w ...
s and phoronids,
and the possible Ediacaran lophophorate ''
Namacalathus
''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.
A U–Pb zircon age ...
''.
Morphology
Tentaculitids have ribbed, cone-shaped shells which range in length from 5 to 20 mm. Some species septate; their embryonic shell, which is retained, forms a small, sometimes spherical, chamber.
Ecology
Some species are inferred to have been planktonic.
See also
*
Mari Mari Group
The Mari Mari Group is an Eifelian to Frasnian geologic group of the Amazon Basin in the state of Amazonas of northwestern Brazil. The group comprises shales and sandstones.state of Amazonas of northwestern Brazil