Microconchida

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. 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. All pre-Cretaceous "Spirorbis" fossils are now known to be microconchids. 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. Their habitat is more controversial. While there is a consensus that they were present in the seas and in brackish water, there is a debate about their presence in freshwater. Some studies suggested that they colonised freshwater in the Early Devonian, whereas others suggest that microconchids never colonised that environment. A recent review of the associated fauna failed to find reliable occurrences of microconchids in the Middle Devonian to Early Permian time interval because microconchids seem to co-occur with other signs of marine influence, such as xiphosurans and chondrichthyan egg capsules.

Microconchida

Wilson44691 · CC BY-SA 3.0 · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.

On record

Recorded, not inferred
Sits inside
TentaculitidaPBDB
Diet
suspension feederPBDB, for Tentaculitida
Life habit
semi-infaunalPBDB, for Tentaculitida
Motility
stationaryPBDB, for Tentaculitida
Vision
blindPBDB, for Tentaculita

Time the record covers

At least 270 million years on record.

The record covers at least 422.7 Mya to 152.21 Mya. No occurrence read is dated outside 425 Mya to 149.2 Mya.

Silurian — about 3 of 219 occurrencesDevonian — about 15 of 219 occurrencesDevonianCarboniferous — about 2 of 219 occurrencesCarboniferousPermian — about 2 of 219 occurrencesPermianEarly Triassic — about 169 of 219 occurrencesMiddle Triassic — about 22 of 219 occurrencesLate Triassic — about 0 of 219 occurrencesEarly Jurassic — about 0 of 219 occurrencesMiddle Jurassic — about 5 of 219 occurrencesLate Jurassic — about 1 of 219 occurrences431–421 Mya — about 3 occurrences411–402 Mya — about 1 occurrence402–392 Mya — about 2 occurrences392–383 Mya — about 10 occurrences383–373 Mya — about 2 occurrences344–335 Mya — about 2 occurrences335–325 Mya — about 0.5 occurrences297–287 Mya — about 0.9 occurrences287–278 Mya — about 1 occurrence258–249 Mya — about 134 occurrences249–239 Mya — about 55 occurrences239–230 Mya — about 2 occurrences182–172 Mya — about 0.6 occurrences172–163 Mya — about 4 occurrences153–144 Mya — about 1 occurrence422.7 Mya152.21 Mya431 Mya144 Mya

219 occurrences of Microconchida on record, most of them in the Early Triassic. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.

When

219 occurrences

These are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.

Found in

39 formations

Wordie Creek — 73.88°N, 21.42°WWordie Creek — 73.85°N, 21.38°WWordie Creek — 74.03°N, 21.60°WWordie Creek — 74.01°N, 21.54°WWordie Creek — 73.99°N, 21.42°WWordie Creek — 74.05°N, 21.70°WWordie Creek — 74.15°N, 21.00°WDaye — 29.45°N, 111.06°EDaye — 25.57°N, 106.66°EDaye — 25.59°N, 106.65°EDaye — 25.58°N, 106.76°EDaye — 25.54°N, 106.67°EDaye — 25.54°N, 106.76°EDaye — 30.17°N, 109.00°EMoenkopi — 37.18°N, 113.22°WMoenkopi — 37.13°N, 113.76°WMoenkopi — 37.06°N, 113.69°WMoenkopi — 37.11°N, 113.25°WMoenkopi — 37.03°N, 113.27°WMoenkopi — 39.00°N, 110.68°WSzin Marl — 48.47°N, 20.68°ESzin Marl — 48.48°N, 20.61°ELuolou — 24.96°N, 106.65°ELuolou — 24.36°N, 107.33°ELuolou — 24.43°N, 107.37°ETrochitenkalk — 51.63°N, 9.03°ETrochitenkalk — 50.75°N, 8.50°ETrochitenkalk — 49.17°N, 10.02°ETrochitenkalk — 50.76°N, 9.81°EBódvaszilas Sandstone — 48.48°N, 20.69°EMeißner — 49.08°N, 9.89°EMeißner — 49.18°N, 10.05°EKuressaare — 58.23°N, 22.44°EKuressaare — 58.25°N, 22.57°EGrzegorzowice — 51.04°N, 21.07°EGrzegorzowice — 50.90°N, 21.16°ECracoe Limestone — 54.05°N, 2.02°WCracoe Limestone — 54.07°N, 2.25°WBead Mountain — 31.48°N, 99.69°WBead Mountain — 32.69°N, 99.38°WKap Stosch — 73.80°N, 21.50°WKirchaou — 33.41°N, 10.42°ETaboumakhloûf — 30.73°N, 4.70°ELudlowville — 42.84°N, 78.60°WMoscow — 42.83°N, 77.88°WKowala — 50.80°N, 20.50°EKowala — 50.82°N, 20.58°EGerennavar Limestone — 48.08°N, 20.45°EWellenkalk — 50.30°N, 18.97°ECandelaria — 38.30°N, 118.06°WKaradagtepe — 41.91°N, 33.72°EWellenkalk — 47.74°N, 8.39°ESzinpetri Limestone — 48.50°N, 20.65°E

Loading coastlines…

The named rock units Microconchida has been recovered from, largest first. Drawn where the rock is now, not where it formed. 15 further formations hold fewer occurrences each and are not listed. 5 occurrences have no formation on record, which is common for older literature.

Microconchida and its relatives

Early Triassic

Where Microconchida and its relatives were recorded in the Early Triassic.

Found in the same rock

713 taxa

The Paleobiology Database records 204 sites for Microconchida, and this reads all of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.

This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.

Entered from

35 references

Each of the 219 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. 23 further references are not listed. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.

Media and terms

Media content1

Picture of Microconchida

Credit
Wilson44691
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

No 3D scan of Microconchida was found in MorphoSource and Sketchfab.

Smithsonian Open Access was not reached for this taxon, so this list is what the others held rather than everything there is.

The description on this site

Licence
CC BY-SA 4.0

This is what the site found, which is not the same as what exists.

Keep going

What may have been alongside itTentaculitida through timeFormations of the Early TriassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Weedon 1991