Typhloesus

Last updated

Typhloesus
Temporal range: Serpukhovian
Typhloesus fossils 2022.jpg
Fossil specimens
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Superphylum: Lophotrochozoa
Phylum: Mollusca (?)
Genus: Typhloesus
(Conway Morris, 1990)
Species:
T. wellsi
Binomial name
Typhloesus wellsi
(Melton and Scott, 1973)

Typhloesus wellsi is an extinct species of enigmatic bilaterian animals from the Bear Gulch Limestone. It was once thought to be the first body fossil of a conodont, based on what turned out to be its gut contents; it is now thought to exhibit a radula, which would make it a mollusc, [1] although different types of animal have independently evolved radula-like features. Mark Purnell, of the Centre for Palaeobiology at the University of Leicester, said that it was not definitively known "what this weird thing is". [2]

Contents

Discovery

Typhloesus was first described back in 1973 from Carboniferous rocks in Montana. [3] The animal was then jokingly referred to as the ‘alien goldfish’ by subsequent studies. [1] Because of its highly enigmatic nature, this organism was only mentioned briefly in several papers. [1] It was then thought to have been the first known body fossil of a conodont, which are a primitive group of jawless agnathan fish distantly related to lampreys and hagfish. [4] This was based on the presence of "conodont elements", which are the small comb-like teeth of those animals. The teeth however were actually located in the gut contents of the Typhloesus, meaning that while it wasn't a conodont, they were a part of its diet. [1] The animals taxonomy would be shrouded in mystery for over 30 years until in September 2022, when a new paper published revealed several potential mollusk-like features of the animal. [1]

Description

Interpretation of Typhloesus as gastropod Typhloesus interpretation 2022.jpg
Interpretation of Typhloesus as gastropod

It has a fusiform (spindle-shaped) body, with a maximum length of 90 mm. At the posterior or backside of the animal is a caudal fin, which was supported by two sets of orthogonal fin rays. The exterior lacks any other organs. The internal anatomy consists of a foregut and a midgut. The gut lacks a midsection and an anus. Beneath the midgut is a disc shaped organ, tentatively called a ferrodiscus; the purpose of this organ is unknown, however it has a high concentration of iron. [3]

Paleoecology

It might have been both a predator and a scavenger, as its fossils sometimes contain conodont teeth and worm teeth located in the midgut of the animal. [1]

See also

Tullimonstrum , another enigmatic animal from the upper Carboniferous of Illinois.

Related Research Articles

<span class="mw-page-title-main">Conodont</span> Extinct agnathan chordates resembling eels

Conodonts are an extinct group of eel-looking agnathan (jawless) vertebrates, classified in the class Conodonta. For many years, they were known only from fossils of their spiky oral elements, which are usually found in isolation and are now called conodont elements, while knowledge about soft tissues remains limited. A resilient group of prehistoric fish, conodonts existed in the world's oceans for over 300 million years, from the Cambrian to the beginning of the Jurassic. Due to their cosmopolitan distribution, conodont elements are widely used as index fossils, fossils used to define and identify geological periods.

<span class="mw-page-title-main">Sclerite</span> Hardened body part

A sclerite is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instead it refers most commonly to the hardened parts of arthropod exoskeletons and the internal spicules of invertebrates such as certain sponges and soft corals. In paleontology, a scleritome is the complete set of sclerites of an organism, often all that is known from fossil invertebrates.

<i>Nectocaris</i> Extinct animal genus

Nectocaris is a genus of squid-like animal of controversial affinities known from the Cambrian period. The initial fossils were described from the Burgess Shale of Canada. Other similar remains possibly referrable to the genus are known from the Emu Bay Shale of Australia and Chengjiang Biota of China.

<span class="mw-page-title-main">Agnatha</span> Infraphylum of jawless fish

Agnatha is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both living (cyclostomes) and extinct species. Among recent animals, cyclostomes are sister to all vertebrates with jaws, known as gnathostomes.

<i>Haikouichthys</i> Extinct genus of jawless fishes

Haikouichthys is an extinct genus of craniate that lived 518 million years ago, during the Cambrian explosion of multicellular life. The type species, Haikouichthys ercaicunensis, was first described in 1999. Haikouichthys had a defined skull and other characteristics that have led paleontologists to label it a true craniate, and even to be popularly characterized as one of the earliest fishes. More than 500 specimens were referred to this taxon and phylogenetic analyses indicates that the animal is probably a basal stem-craniate. Some researchers have considered Haikouichthys to be synonymous with the other primitive chordate Myllokunmingia, but subsequent studies led by the British paleontologist Simon Conway Morris identified both genera to be distinct, separate taxa on the basis of different gill arrangement, the absence of branchial rays in Myllokunmingia and the myomeres having a more acute shape in Haikouichthys.

<i>Tullimonstrum</i> Extinct genus of soft-bodied sea animals

Tullimonstrum, colloquially known as the Tully monster or sometimes Tully's monster, is an extinct genus of soft-bodied bilaterian animal that lived in shallow tropical coastal waters of muddy estuaries during the Pennsylvanian geological period, about 300 million years ago. A single species, T. gregarium, is known. Examples of Tullimonstrum have been found only in the Essex biota, a smaller section of the Mazon Creek fossil beds of Illinois, United States. Its classification has been the subject of controversy, and interpretations of the fossil have likened it to molluscs, arthropods, conodonts, worms, tunicates, and vertebrates. This creature had a mostly cigar-shaped body, with a triangular tail fin, two long stalked eyes, and a proboscis tipped with a mouth-like appendage. Based on the fossils, it seems this creature was a nektonic carnivore that hunted in the ocean’s water column. When Tullimonstrum was alive, Illinois was a mixture of ecosystems like muddy estuaries, marine environments, and rivers and lakes. Fossils of other organisms like crustacean Belotelson, the cnidarian Essexella, and the elasmobranch fish Bandringa have been found alongside Tullimonstrum.

<i>Kimberella</i> Primitive Mollusc-like organism

Kimberella is an extinct genus of bilaterian known only from rocks of the Ediacaran period. The slug-like organism fed by scratching the microbial surface on which it dwelt in a manner similar to the gastropods, although its affinity with this group is contentious.

<i>Cladoselache</i> Extinct genus of chondrichthyans

Cladoselache is an extinct genus of shark-like chondrichthyan from the Late Devonian (Famennian) of North America. It was similar in body shape to modern lamnid sharks, but was not closely related to lamnids or to any other modern (selachian) shark. As an early chondrichthyan, it had yet to evolve traits of modern sharks such as accelerated tooth replacement, a loose jaw suspension, enameloid teeth, and possibly claspers.

<i>Wiwaxia</i> Genus of Cambrian animals

Wiwaxia is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. Wiwaxia fossils—mainly isolated scales, but sometimes complete, articulated fossils—are known from early Cambrian and middle Cambrian fossil deposits across the globe. The living animal would have measured up to 5 centimetres (2 in) when fully grown, although a range of juvenile specimens are known, the smallest being 2 millimetres (0.08 in) long.

<i>Ottoia</i> Extinct genus of priapulid worms

Ottoia is a stem-group archaeopriapulid worm known from Cambrian fossils. Although priapulid-like worms from various Cambrian deposits are often referred to Ottoia on spurious grounds, the only clear Ottoia macrofossils come from the Burgess Shale of British Columbia, which was deposited 508 million years ago. Microfossils extend the record of Ottoia throughout the Western Canada Sedimentary Basin, from the mid- to late- Cambrian. A few fossil finds are also known from China.

<span class="mw-page-title-main">Halkieriid</span> Family of extinct molluscs

The halkieriids are a group of fossil organisms from the Lower to Middle Cambrian. Their eponymous genus is Halkieria, which has been found on almost every continent in Lower to Mid Cambrian deposits, forming a large component of the small shelly fossil assemblages. The best known species is Halkieria evangelista, from the North Greenland Sirius Passet Lagerstätte, in which complete specimens were collected on an expedition in 1989. The fossils were described by Simon Conway Morris and John Peel in a short paper in 1990 in the journal Nature. Later a more thorough description was undertaken in 1995 in the journal Philosophical Transactions of the Royal Society of London and wider evolutionary implications were posed.

<i>Odontogriphus</i> Genus of soft-bodied animals from middle Cambrian

Odontogriphus is a genus of soft-bodied animals known from middle Cambrian Lagerstätte. Reaching as much as 12.5 centimetres (4.9 in) in length, Odontogriphus is a flat, oval bilaterian which apparently had a single muscular foot and a "shell" on its back that was moderately rigid but of a material unsuited to fossilization.

<span class="mw-page-title-main">Bear Gulch Limestone</span>

The Bear Gulch Limestone is a limestone-rich geological lens in central Montana, renowned for the quality of its late Mississippian-aged fossils. It is exposed over a number of outcrops northeast of the Big Snowy Mountains, and is often considered a component of the more widespread Heath Formation. The Bear Gulch Limestone reconstructs a diverse, though isolated, marine ecosystem which developed near the end of the Serpukhovian age. It is a lagerstätte, a particular type of rock unit with exceptional fossil preservation of both articulated skeletons and soft tissues. Bear Gulch fossils include a variety of fish, invertebrates, and algae occupying a number of different habitats within a preserved shallow bay.

<i>Falcatus</i> Extinct genus of cartilaginous fishes

Falcatus is an extinct genus of falcatid chondrichthyan which lived during the early Carboniferous Period in Bear Gulch bay in what is now Montana.

<span class="mw-page-title-main">Halwaxiida</span> Proposed clade of extinct Lophotrochozoa

Halwaxiida or halwaxiids is a proposed clade equivalent to the older orders Sachitida He 1980 and Thambetolepidea Jell 1981, loosely uniting scale-bearing Cambrian animals, which may lie in the stem group to molluscs or lophotrochozoa. Some palaeontologists question the validity of the Halwaxiida clade.

The fossils of the Burgess Shale, like the Burgess Shale itself, are fossils that formed around 505 million years ago in the mid-Cambrian period. They were discovered in Canada in 1886, and Charles Doolittle Walcott collected over 65,000 specimens in a series of field trips up to the alpine site from 1909 to 1924. After a period of neglect from the 1930s to the early 1960s, new excavations and re-examinations of Walcott's collection continue to reveal new species, and statistical analysis suggests that additional discoveries will continue for the foreseeable future. Stephen Jay Gould's 1989 book Wonderful Life describes the history of discovery up to the early 1980s, although his analysis of the implications for evolution has been contested.

<span class="mw-page-title-main">Evolution of fish</span> Origin and diversification of fish through geologic time

The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys. During the late Cambrian, eel-like jawless fish called the conodonts, and small mostly armoured fish known as ostracoderms, first appeared. Most jawless fish are now extinct; but the extant lampreys may approximate ancient pre-jawed fish. Lampreys belong to the Cyclostomata, which includes the extant hagfish, and this group may have split early on from other agnathans.

<span class="mw-page-title-main">Conodont feeding apparatus</span> Series of mineralized elements which are found lining the oral surface of the conodont animal

The conodont feeding apparatus is a series of phosphatic-mineralized elements, resembling a set of “teeth”, which are found lining the oral surface of the conodont animal.

<i>Panderodus</i> A venomous Conodont from the Early Paleozoic

Panderodus Is an extinct genus of jawless fish belonging to the order Conodonta. This genus had a long temporal range, surviving from the middle Ordovician to late Devonian. In 2021, extremely rare body fossils of Panderodus from the Waukesha Biota were described, and it revealed that Panderodus had a more thick body compared to the more slender bodies of more advanced conodonts. It also revealed that this conodont was a macrophagous predator, meaning it went after large prey.

The Cambrian chordates are an extinct group of animals belonging to the phylum Chordata that lived during the Cambrian, between 538 and 485 million years ago. The first Cambrian chordate known is Pikaia gracilens, a lancelet-like animal from the Burgess Shale in British Columbia, Canada. The discoverer, Charles Doolittle Walcott, described it as a kind of worm (annelid) in 1911, but it was later identified as a chordate. Subsequent discoveries of other Cambrian fossils from the Burgess Shale in 1991, and from the Chengjiang biota of China in 1991, which were later found to be of chordates, several Cambrian chordates are known, with some fossils considered as putative chordates.

References

  1. 1 2 3 4 5 6 Conway Morris, Simon; Caron, Jean-Bernard (2022). "A possible home for a bizarre Carboniferous animal: Is Typhloesus a pelagic gastropod?". Biology Letters. 18 (9). doi: 10.1098/rsbl.2022.0179 . PMC   9489302 . PMID   36126687.
  2. Davis, Nicola (21 September 2022). "'Alien goldfish' may have been unique mollusc, say scientists". The Guardian.
  3. 1 2 Conway Morris, Simon (1990-04-12). "Typhloesus wellsi (Melton and Scott, 1973), a bizarre metazoan from the Carboniferous of Montana, U. S. A". Philosophical Transactions of the Royal Society of London. B, Biological Sciences. 327 (1242): 595–624. Bibcode:1990RSPTB.327..595M. doi:10.1098/rstb.1990.0102.
  4. Miyashita, Tetsuto; Coates, Michael I.; Farrar, Robert; Larson, Peter; Manning, Phillip L.; Wogelius, Roy A.; Edwards, Nicholas P.; Anné, Jennifer; Bergmann, Uwe; Palmer, A. Richard; Currie, Philip J. (2019-02-05). "Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological–molecular conflict in early vertebrate phylogeny". Proceedings of the National Academy of Sciences. 116 (6): 2146–2151. Bibcode:2019PNAS..116.2146M. doi: 10.1073/pnas.1814794116 . ISSN   0027-8424. PMC   6369785 . PMID   30670644.