Microconchida Temporal range:
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Palaeoconchus angulatus (Hall, 1861) on a brachiopod from the Middle Devonian (Givetian) of Michigan | |
Scientific classification
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Domain: | Eukaryota |
Kingdom: | Animalia |
Class: | † Tentaculita |
Order: | †
Microconchida Weedon 1991 |
Genera | |
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]
Microconchida Temporal range:
| |
---|---|
![]() | |
Palaeoconchus angulatus (Hall, 1861) on a brachiopod from the Middle Devonian (Givetian) of Michigan | |
Scientific classification
![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Class: | † Tentaculita |
Order: | †
Microconchida Weedon 1991 |
Genera | |
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]