Microconchida

Microconchida
Temporal range: Upper Ordovician - Middle Jurassic (Taylor and Vinn, 2006)
Palaeoconchus angulatus (Hall, 1861) on a brachiopod from the Middle Devonian (Givetian) of Michigan
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Class: †Tentaculita
Order: †Microconchida
Weedon 1991
Genera
Helicoconchus elongatus, a microconchid from the Lower Permian of Texas. (See Wilson et al., 2011).
Punctaconchus midfordensis (Richardson, 1907). Bajocian, Clypeus Grit Member, Worgan's Quarry, Gloucestershire, UK.

The order Microconchida is a group of small, spirally-coiled, encrusting fossil "worm" tubes from the class Tentaculita found from the Upper Ordovician to the Middle Jurassic (Bathonian) around the world.[1][2][3][4][5] They have lamellar calcitic shells, usually with pseudopunctae or punctae and a bulb-like origin. Many were long misidentified as the polychaete annelid Spirorbis until studies of shell microstructure and formation showed significant differences.[6] All pre-Cretaceous "Spirorbis" fossils are now known to be microconchids.[6] Their classification at the phylum level is still debated. Most likely they are some form of lophophorate, a group which includes phoronids, bryozoans and brachiopods. Microconchids may be closely related to the other encrusting tentaculitoid tubeworms, such as Anticalyptraea, trypanoporids and cornulitids.[3]

  1. ^ Cite error: The named reference Weedon91 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Vinn2006 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Vinn2010 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference VinnMutvei2009 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference ZatonVinn2011 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference TaylorVinn was invoked but never defined (see the help page).