recursal/Fanatic-Fandom huggingface dataset:
Clepsydrops

Credit: Dimitry Bogdanov.

*Clepsydrops* is an extinct genus of Ophiacodontid that lived in North America during the Late Carboniferous.

## Description

*Clepsydrops* likely ate insects and layed its eggs on land. *Clepsydrops*' femur indicates that the animal had a primarily terrestrial lifestyle. This factor is also consistent with *Clepsydrops*' compact and thin cortex. The animals jaws are slightly more advanced than those of *Paleothyris* or *Hylonomus*.

## Classification

*Clepsydrops* is very closely related to *Ophiacodon* and even closer related to *Archaeothyris*.

## Species

* *C. collettii*
* *C. natalis*
* *C. vinslovii*

## References

https://en.wikipedia.org/wiki/Clepsydrops
Conacodon

Left to right: Conacodon hettingeri, Miniconus jeanninae and Beornus. Credit: Banana Art Studio.

## Statistics

### Diet

Carnivorous

*Conacodon* is an extinct genus of periptychid mammal that lived in Colorado, New Mexico, Utah, and Wyoming during the Paleocene.

## Classification

In 2021, *C. hettingeri* was named alongside *Miniconus* and *Beornus* based on differing M3 morphology, recovered as a basal member of its clade. It is from UCM locality 2011035.

## Species

* *C. cophater*
* *C. delphae*
* *C. harbourae*
* *C. hettingeri*
* *C. kohlbergeri*
* *C. matthewi*

## References

* https://paleobiodb.org/classic/basicTaxonInfo?taxon\_no=42271
* https://www.tandfonline.com/doi/full/10.1080/14772019.2021.1924301
Ctenorhabdotus

Credit: Marianne Collins.

*Ctenorhabdotus* is an extinct genus of Ctenophore that lived in Canada during the Middle Cambrian.

## Description

*Ctenorhabdotus* is characterized by 24 comb rows, three times the amount modern comb jellies have. Both the top and bottom surfaces are relatively flat. Each group of three combs join at the arboreal side and form 8 strands. At the arboreal side of the organism, is a strange capsule-like structure which is theorized to contain an apical organ and statocysts.

## References

* https://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=41
* https://en.wikipedia.org/wiki/Ctenorhabdotus
Caelestiventus

Credit: Joschua Knüppe.

*Caelestiventus* is an extinct genus of rhamphorhynchoids that lived in North America during the Late Triassic.

## Description

*Caelestiventus* is known from a single intact mandible in Utah. The skull had toothy jaws, and a small dip at the end of the lower jaw. The specimen had not reached full maturity. *Caelestiventus* would have been comparable in size to that of *Dimorphodon*, to which it was closest related. The (still 3D) skull shows the internal chambers of pterosaur skulls. *Caelestiventus* had a minor dip on its forehead, the level it was pronounced is relatively unknown.

## Notable Specimens

* BYU 20707: The holotype of *Caelestiventus* is a single, well preserved, mandible found in Utah. The bone growth shows that the individual this mandible once belonged to was not a mature adult.

## References

https://en.wikipedia.org/wiki/Caelestiventus
Daedalosphaera

*Daedalosphaera* is an extinct genus of spheroidal acritarch that lived in the Canadian Arctic during the Neoproterozoic.

## History

The name refer to the Greek mythological figure Daedalus, who built the Cretan labyrinth, due to the patterns in the vesicle wall structure. The epithet derives from the Latin digiti, meaning "fingers" and signa, meaning "sign" or "imprint". This is because of the structures mimicking a fingerprint in the wall.

## Description

*Daedalosphaera* is known from hundreds of specimens from specimen 74640-F52,3, of sample 15RAT-021A1, with varying levels of preservation. The vesicles are circular or sub-circular with a (more-or-less) optically dense wall. It is smooth on the outside and adorns a rugulate surface comprised of random ridges and grooves, which are of various lengths and have a constant width on the inner surface. Through the medial split, the vesicle excysts.

## References

https://www.sciencedirect.com/science/article/pii/S030192681830216X?via%3Dihub
Daxiatitan

Credit: Cisiopurple on DeviantArt.

*Daxiatitan* is an extinct genus of basal titanosaur that lived in China during the Early Cretaceous.

## Description

*Daxiatitan* is known from several neck vertebrae, a single shoulder blade and a thigh bone. Based on a femur 57 centimeters wide, the sauropod was 23-30 meters (75-98 feet), with a weight of 30,000 kilograms estimated in January of 2020. *Daxiatitan* had an extremely long neck, like similar sauropods *Huanghetitan* and *Eohelopus*.
Cynthiacetus

Credit: Heraldo Mussolini.

*Cynthiacetus* is an extinct genus of Basilosaurid that lived in Peru and the United States during the Late Eocene.

## Description

The skull of *Cynthiacetus* is similar in size and in morphology to *Basilosaurus*. The genus was erected in 2005 by Uhen to avoid the dubious *Pontogeneus*. *Cynthiacetus* was smaller than *Masracetus*. *C. peruvianus* is known from Peru, being the first archaeocete described from South America. C. maxwelli is known from the southwestern United States. *C. peruvianus* differs from *C. maxwelli* mainly through cuspid count on the lower premolars, and having 20 thoracic vertebrae.

## References

https://en.wikipedia.org/wiki/Cynthiacetus
Diracodon

*Diracodon* is a dubious genus of dinosaur that lived in North America during the Late Jurassic.

## Classification

*Diracodon* was named by Marsh in 1881, based on several mandibular fragments. In 1986, Bakker resurrected *Diracodon* as a junior synonym of *Stegosaurus stenops*; however, the material is non-diagnostic, only referable to *Stegosaurus sp.*, making it a nomen dubium.

## References

https://en.wikipedia.org/wiki/Stegosaurus
Concentrilepis

Before formal naming or identification, this organism was known as the following on this wiki:
**Minnekahta actinopterygian**

## Statistics

### Diet

Carnivorous?

*Concentrilepis* is an extinct of ray-finned fish that lived in South Dakota during the Early Permian.

## Description

This genus is represented by PF 3721 and YPM 18649 of the Late Early Permian; the first is a 3D exceptionally-preserved head and trunk with great detail on the outside as well as internal cranial, paired fins and scale features. The second is partially-articulate but laterally compressed with an extremely disarticulate skull.

This taxon has an immobile maxilla with a narrow suborbital process and a postorbital expansion that is barrow, a caudal fin that is heterocaudal and rhombic glenoid scales, which are shared with paleoniscoids. The snout is prominent, the lacrimal is excluded from the oral margin, pectorals that are broad and triangular, dorsal and anal fins that are triangular, a caudal that is deeply-forked, scales with straight concentric ridges sitting at the marines sitting parallel to their margin and diagonal ridges at the center.

## Classification

It sits in a polytomy with Late Paleozoic and Early Mesozoic Paleoniscoids, but many interrelationships are unresolved amongst them. It was first previewed in the 2021 SVP abstracts before being published as a dissertation/thesis online. A line in the figure listing leaked the name *Concentrilepis minnekahtaensis*. In March of 2022, the genus was officially published under the same name.

## References

* https://vertpaleo.org/wp-content/uploads/2021/10/SVP\_2021\_VirtualBook\_final.pdf
* https://www.proquest.com/openview/2f226585d17d91cbd1df478c4b37c019/1?pq-origsite=gscholar&cbl=18750&diss=y (thesis pre-publication)
* https://www.tandfonline.com/doi/full/10.1080/14772019.2022.2036837
Desmostylus

Credit: Fresno Co., CA, @calacademy.

*Desmostylus* is an extinct genus of desmostylid mammal that lived in Mexico, the United States, Japan and Russia from the Late Oligocene to the Late Miocene.

## History

Marsh (1888) named *D. hesperus* as the type based on a set of isolate teeth near Mission San Jose, California (37.6°N 121.9°W; paleocoordinates 36.8°N 117.6°W). Marsh has described it as a sirenian and proposed relations with *Metaxytherium* and *Halicore*. Other species are diagnosed by minor morphological differences in the teeth, but most were synonymized with the type since it was shown to bear great variation. *D. japonicus* was described by Yoshiwara and Iwasaki (1902) based on a well preserved partial skull, and named by Tokunaga and Iwasaki (1914).

## Description

*Desmostylus* is a bulky animal with a short tail and powerful hooved legs, convergent to a hippopotamus. The elongate jaws bore elongate canines and incisors. It was likely semiaquatic or fully aquatic, thought to have lived in shallow coastal regions. It was argued to have fed on seaweed during low tide, but isotope analyses found it to be fresh or estuary ecosystems, feeding on aquatic plants. It is unknown if it was aggressive or omnivorous, like hippos are, or if they were passive prey. A tooth described in 2023 from the Skooner Gulch Formation bears cuspules surrounding the crown, a basal trait in the family and implies that a distinct morph of *Desmostylus* remained virtually unchanged for over 15 million years in west North America.

## Synonyms

* Desmostylella
* *Vanderhoofius*
* *D. watasei* (=*D. hesperus*)
* *D. cymatias* (=*D. hesperus*)
* *D. californicus* (=*D. hesperus*)
* *D. mirabilis* (=*D. hesperus*)
* *D. minor* (=*D. hesperus*)

## References

* https://paleobiodb.org/classic/checkTaxonInfo?a=checkTaxonInfo&taxon\_no=36958
* https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3615000/
* https://www.sciencedirect.com/science/article/abs/pii/S0031018217301372
* https://ucmp.berkeley.edu/mammal/mesaxonia/desmostylia.html
* https://www.researchgate.net/figure/Skeletal-remains-of-Miocene-Desmostylus-hesperus-and-Paleoparadoxia-tabatai-A\_fig1\_30845734
* https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6800978/
* http://scotdir.com/home/sciences-3/extinct-mammals-desmostylus
* https://royalsocietypublishing.org/doi/10.1098/rsos.221648
Edmarka

Credit: Sergey Krasovskiy.

*Edmarka* is a dubious genus of megalosaurid that lived in North America during the Late Jurassic.

## Description

*Edmarka* must have been an apex predator in the Morrison Formation during the Late Jurassic. Along with *Torvosaurus*, *Allosaurus* and *Saurophaganax* (if *Edmarka* is a valid genus) would have been at the top of the food chain. This large number of animals filling the niche of apex predator challenges Bakker's theory of ecosystems only seeming to support one apex predator. It was a carnivore, possibly one of the largest in its habitat.

## References

* https://www.nationalgeographic.com/science/article/t-is-for-torvosaurus
* Bakker, R. T., et al. "Edmarka rex, a new, gigantic theropod dinosaur from the middle Morrison Formation, Late Jurassic of the Como Bluff outcrop region." Hunteria 2.9 (1992): 1-24.
Cheirolepis

*Cheirolepis* is an extinct genus of ray-finned fish that lived in Europe and North America from the Middle to the Late Devonian.

## Description

*Cheirolepis* is one of the earliest ray-finned fish known to science. Its spine is made up of bone and gristle, making it exceptionally difficult to preserve in fossils. The fish was covered in small overlapping scales that were thickly coated with ganoin, a type of enamel, allowing it to reach speeds needed to catch fast-moving prey in freshwater pools and streams. It could open its jaws very wide to swallow animals two-thirds of its own length. The animal jaws were line with pointy teeth. *Cheirolepis* also has well-developed fins, which act as stabilizers for an active predatory lifestyle. Based on its eyes, *Cheirolepis* was a sight-based hunter. One specimen consists of scales and a lower jaw, which represent an unnamed species once attributed to *C. canadensis*. Many specimens are known.

## Species

* *C. trailli*
* *C. canadensis*
* *C. gaugeri*
* *C. gracilis*
* *C. macrocephalus*
* *C. sinualis*
* *C. sp.* (unnamed)

## References

1. Dorling Kindersley Encyclopedia of Dinosaurs and Prehistoric Life, p. 48
2. https://en.wikipedia.org/wiki/Cheirolepis
Ceratodus

*Ceratodus* is an extinct genus of freshwater lungfish that lived worldwide during the Mesozoic and went extinct at the beginning of the Eocene.

## Description

The toothplates in *Ceratodus*' jaws allowed it to crunch down on hard-shelled food. *Ceratodus* has gills, however, the fish also has the option to breathe through its nostrils at the waters surface. Multiple species have been mistaken for *Neoceratodus*. *C. forsteri*, *C. blanchardi* and *C. miolepis* are all classified as synonyms of *Neoceratodus*. Fossils of *Ceratodus* are known from United States, Argentina, Greenland, England, Germany Egypt, Madagascar, China and Australia.

## Species

* *C. latissimus*
* *C. eruciferus* (dubious)
* *C. hieroglyphus* (dubious)
* *C. robustus*
* *C. africanus*
* *C. humei*
* *C. elegans*
* *C. frazieri*
* *C. gustasoni*
* *C. fossanovum*
* *C. stewarti*
* *C. texanus*
* *C. carteri*
* *C. kranzi*
* *C. kirklandi*
* *C. molossus*
* *C. kempae*
* *C. nirumbee*
* *C. tunuensis*
* *C. sp.* (undescribed)

## References

* Dorling Kindersley Encyclopedia of Dinosaurs and Prehistoric Life, p. 52
* https://en.wikipedia.org/wiki/Ceratodus
Ceratoptera

Leidy's specimen.

*Ceratoptera* is a dubious genus of ray that lived in the United States during the Upper Plio- or Pleistocene

## History

*Ceratoptera* was likely around 3-4 meters wide, based on preserved dermal denticles known from the Waccamaw Formation. This genus was first coined by Leidy (1877) from denticles of an unknown locality in Charleston, South Carolina. However, the discovery of more similar dermal bucklers by Ashby Gale in 2018 has revealed that it is likely synonymous with the extant ray *Bathytoshia centroura*. The use of stratigraphy reveals that Leidy's specimen was likely from the Plio- or Pleistocene. Though the new elements are much smaller, they are very similar. Thus, the synonymy between the two is plausible but pending results.

## References

* https://twitter.com/CofCNatHistory/status/1484935301906771979
* https://link.springer.com/article/10.1007/s12542-021-00592-5
Chassternbergia

AMNH 5381.

*Chassternbergia* is a dubious genus of nodosaur that lived in Alberta, Canada during the Late Cretaceous.

## Classification

*Chassternbergia* was named by Robert Bakker in 1988 as a subgenus of *Edomontonia rugosidens*, and later met with heavy criticism. After further research, *Chassternbergia* was dubbed a synonym of *Edmontonia*.

*Chassternbergia* is based off of skull differences from *Edmontonia longiceps*, like skull proportions, size and age. The remains were published as *Edmontonia (Chassternbergia) rugosidens*, published by Bakker. Robert Bakker also erected Edmontoniinae, to house *Chassternbergia*, *Edmontonia* and *Denversaurus*, which was housed in Stegosauria. The family has been reevaluated, and placed back into Ankylosauria.

## References

* http://www.dinochecker.com/dinosaurs/CHASSTERNBERGIA
* https://en.wikipedia.org/wiki/Edmontonia#Discovery\_and\_species
* https://en.wikipedia.org/wiki/1988\_in\_paleontology#Newly\_named\_non-avian\_dinosaurs
Chiapas amber crabs

* Figure 1
* Figure 2

The Chiapas amber crabs are a collection of unnamed juvenile crab genera known from Mexico during the Early Miocene.

*(**Fig. 1**: several amber specimens compared; IHNFG-4991, IHNFG-5555, IHNFG-5316 and IHNFG-4992. **Fig 2**: Analysis and comparison of specimens IHNFG-4992, IHNFG-4969, IHNFG-4970, IHNFG-4912, IHNFG-4929 and IHNFG-4993 with the living Pseudosesarma bocourti.)*

## Description

Each crab is known from the Campa La Granja mines that date to the Early Miocene. They all fit into Sesaarmidae, an extant group of crabs. These, along with *Cretapsara athanata* from Burmese Amber are the only known crabs included in amber*.* These have been described, but not named. Most specimens are noted to resemble the extant monotypic genus of crabs, *Metopaulias*, and possibly are associated with it. One specimen resembles the extant genus *Sesarma*, which are frequently found near mangrove trees. Nine specimens are reported from the same mines; three small complete crabs, two partial, three isolated pereiopods and a single endophragmal fragment. One specimen possibly represents an individual encased shortly after molting, These could even represent exuviae or decaying carcasses that had died in the ponds the tree resin had settled in. Sesarmid crabs are diverse in biology, being saltwater, freshwater, terrestrial, aquatic and mangrove-climbers. It is thought these individuals lived in a paleoenvironment covered in floodplains with mangroves and strong tides.

Each crab carcass includes notable pincers, wide cephalothoraxes, rugose textures across the latter and standard recognizable crab features. One specimen contains a termite, which also possesses pyritization.

## Paleoecology

It is thought these crabs lived in ponds and climbed mangrove trees, possibly swept into resin by tides. The area these specimens inhabited is primarily estuaries, with remains of amber-included plant matter, termites, ostracods, flies and hemipterans, primarily known for its arthropods. They and reported amphipods would have to have been deceased before the resin swept them, unlike the other invertebrates, who were probably scavenged by predators such as birds and lizards.

About 110 amber pieces were examined in a 2015 study, showing the crabs lived with plants, nematodes, copepods, ostracods, tanaidaceans, amphipods, isopods, aquatic collembola, coleopterans and other insects. Around seven individuals known from small corpses and carcasses, with two thought to have been alive when the resin incased them. Apparently, slightly larger specimens are reported with their cuticles covered in fine mud, which has been interpreted as either molted exoskeletons or decaying corpses. *Hymenea sp.* and freshwater insect larvae were present, the latter indicates the area included freshwater.

## References

* http://www.scielo.org.mx/scielo.php?script=sci\_arttext&pid=S1405-33222016000100037
* https://www.researchgate.net/publication/281759948\_The\_aquatic\_and\_semiaquatic\_biota\_in\_Miocene\_amber\_from\_the\_Campo\_LA\_Granja\_mine\_Chiapas\_Mexico\_Paleoenvironmental\_implications
CCG 20011

CCG 20011 is an unnamed genus of Elaphrosaurine Ceratosaur that lived in China from the Middle to Late Jurassic.

## Description

The taxon is known from 3rd, the 4th and the 10th dorsal vertebrae, the 3rd dorsal centrum, a partial proximal caudal vertebra, 4 complete distal caudal vertebrae as well as a partial 5th, and part of the scapula. He Xinlu originally assigned this specimen as a paratype of the theropod *Chuandongocoelurus*. The remains however differ greatly from *Chuandongocoelurus*, and are more comparable to that of *Elaphrosaurus*. The specimen differs from *Elaphrosaurus* in the anatomy of the neural arch and postzygopophyses.

## Classification

CCG 20011 represents the sister taxon to *Elaphrosaurus*, with *Limusaurus* being the sister taxon to the clade shared by *Elaphrosaurus* and CCG 20011.

## References

https://en.wikipedia.org/wiki/Chuandongocoelurus

https://www.theropoddatabase.com/Ceratosauria.htm#Elaphrosaurinae

https://en.wikipedia.org/wiki/Elaphrosaurus#Classification
Cyclura

This page is about a genus that contains extinct and extant species; species marked with † are extinct.

## Statistics

### Diet

Herbivorous

*Cyclura* is a a genus of iguanid squamate that has lived in the Caribbean since the Quaternary.

## Species

* *C. carinata* (Turks and Caicos rock iguana)
	+ *C. c. bartschi* (Bartch's iguana)
* *C. collei* (Jamaican iguana)
* *C. cornuta* (Rhinoceros iguana)
	+ †*C. c. onchiopsis*?
* *C. cychlura* (Northern Bahamian rock iguana)
	+ *C. c. cychlura* (Andros Island iguana)
	+ *C. c. figginsi* (Exuma Island iguana)
	+ *C. c. inornata* (Allen Cays iguana)

* *C. lewisi* (Grand Cayman blue iguana)
* *C. nubila* (Cuban iguana)
	+ *C. n. caymanensis*
	+ *C. n. nubila*
* *C. pinguis* (Anegada ground iguana)
* *C. ricordii* (Ricord's iguana)
* *C. rileyi* (San Salvador iguana)
	+ *C. r. cristata* (White Cay iguana)
	+ *C. r. nuchalis* (Acklins iguana)
* *C. stejngeri* (Mona Island iguana)
* †*C.* n. sp.

## References

* https://en.wikipedia.org/wiki/Cyclura
* https://www.lulu.com/en/ca/shop/society-of-vertebrate-paleontology/svp-2017-program-and-abstracts/paperback/product-1p7ydk5e.html?page=1&pageSize=4
* https://paleobiodb.org/classic/basicTaxonInfo?taxon\_no=37861
Dimetrodon

Credit: Max Bellomio.

*Dimetrodon* is an extinct genus of early synapsid that lived during the Early Permian of the United States.

## Description

*Dimetrodon* is more related to modern mammals than reptiles. The legs of *Dimetrodon* is highly debated. Most think Dimetrodon had a sprawled posture with an upright running posture for a short while while sprinting. The sail on Dimetrodon's back was used for display or for temperature regulation. Scientists now think that the tips on *Dimetrodon*'s sail stuck out. The skull of Dimetrodon features a large hook-like indentation for holding onto prey. The first tooth on the upper jaw was larger than the following two and got larger the farther back in the skull they were. *Dimetrodon*'s tail was short and rat-like and likely dragged on the ground lightly.

## Paleoecology

*Dimetrodon* was the apex predator of its habitat. *Dimetrodon*'s habitat was likely arid, with low but dense vegetation. Amongst the vegetation was the herbivorous *Edaphosaurus* and the carnivorous *Ophiacodon*. Studies show that *Dimetrodon* was the main predator in Permian United States.

## Synonyms

### Genus Synonymy

* *Embolophorus*
* *Theropleura*
* *Bathyglyptus*
* *Eosyodon*

### Species Synonymy

* *Clepsydrops limbatus*
* *Clepsydrops gigas*
* *Clepsydrops natalis*
* *D. gigas*
* *D. incisivus*
* *D. rectiformis*
* *D. semiradicatus*
* *Clepsydrops macrospondylus*
* *D. platycentrus*
* *D. maximus*

## Species

* *D. angelensis*
* *D. borealis*
* *D. booneorum*
* *D. dollovianus*
* *D. gigahomogenes*
* *D. grandis*
* *D. kempae* (nomen dubium?)
* *D. limbatus*
* *D. loomisi*
* *D. macrospondylus*
* *D. milleri*
* *D. natalis*
* *D. occidentalis*
* *D. teutonis*

## Notable Specimens

* WMNH coll. "Bonnie": A *Dimetrodon* specimen that was talked about at PaleoFest 2022 by Chris Flis (who had been working on it for years) in a slideshow presentation. It was also noted to be one of the best Dimetrodon specimens known by the official WMNH Twitter in 2018. It was collected in 2017, alongside a Diplocaulus nicknamed "Holly". Chris Zorel helped prepare the specimen. It measures 6 feet across.

## Gallery

"Bonnie" after preparation."Bonnie" after retrieval.Chris Zorel preparing "Bonnie".Close ups of "Bonnie" shared in 2022.*D. grandis* at the ROyal Ontario Museum.
**Credit: Clumsystiggy on DeviantArt.***D. grandis* at the Royal Ontario Museum.
**Credit: Clumsystiggy on DeviantArt.**
## References

* https://en.wikipedia.org/wiki/Dimetrodon
* https://twitter.com/DarthZorel/status/997359872642551810
* https://twitter.com/WhitesideMuseum/status/947302201562714112
* https://twitter.com/WhitesideMuseum/status/1022520310476800002/photo/1
* https://twitter.com/ToddRockford/status/1500196598944608259
Cordulagomphus

*Cordulagomphus* is an extinct genus of dragonflies that lived during the Cretaceous in Brazil

## Description

*Cordulagomphus* have an elongated tail, with four large wings and two long antennae. *Paracordulagomphus* is considered a subgenus of *Cordulagomphus*.

## Species

* *C. europaeus*
* *C. fenestratus*
* *C. hanneloreae*
* *C. tuberculatus*
* *C. winkelhoferi*

## References

* https://en.wikipedia.org/wiki/Cordulagomphus
* https://paleobiodb.org/classic/basicTaxonInfo?taxon\_no=175160
Alexandronectes

*Alexandronectes* is an extinct genus of plesiosaur that lived in New Zealand during the Late Cretaceous.

## Description

*Alexandronectes* is classified in aristonectinae because of its A-shaped squamosal arch and the structure of the pterygoid muscle. *Alexandronectes* differs from known aristonectines because of its small skull, paroccipital processes and its mandibular glenoid.

## References

https://en.wikipedia.org/wiki/Alexandronectes
Doryaspis

Credit: Franz Anthony.

*Doryaspis* is an extinct genus of jawless fish that lived in Norway during the Early Devonian.

## Description

*Doryaspis* is generally shaped like a triangle; with a barbed pseudorostrum, two spined fins and a plated tail. The pseudorostrum extends outwards from the lower lip/chin. The tail is adorned with thick plated scales, and is terminated in small fins. The eyes are on top of the body, separated by a small ridge in the shield.

## Species

* *D. arctica*
* *D. groenhorgensis*
* *D. minor*
* *D. nathorsti*
Corumictis

Credit: Henry Sharpe.

*Corumictis* is an extinct genus of mustelid that lived in North America during the Early to Late Oligocene.

## Description

*Corumictis* is known from a single skull, discovered in North America. The skull shows how the mustelids evolved, and their presence in the Early/Late Oligocene, North America. *Corumictis* is a sister taxon to *Plesictis julieni*.

## References

http://novataxa.blogspot.com/2020/03/corumictis.html
Gigatitan

Gigatitan vulgaris according to Schubnel et al. (2021).

*Gigatitan* is an extinct genus of Titanopteran that lived in Kyrgyzstan from the Middle to the Late Triassic.

## Description

*Gigatitan vulgaris* was described in 1968 by Aleksandr Grigorevich Sharov. Fossils are typically found from the Madygen Formation, which preserves Mid/Late Triassic fossils. *Gigatitan* was remarkably mantis-like, having a set of wings 33 centimeters (13 inches) in wingspan, with one individual spanning 155 centimeters across, such a large size is questionable. Remains have little documentation, with photos and specimen figures being rare. Additionally, plate tectonics could have stretched the wingspan over time, as the formation is known to have flexible rock. If this is the case, the 155 specimen would instead be ~37 centimeters across, still larger than any modern airborne insect.

The insect had the characteristic mantis-like forelimbs, lined with sharp spines to aid in capture and holding of prey. The ovipositor is also lined with many barbs, likely to cut holes into leaves, like modern Orthoptera. *Gigatitan* is the type of Gigatitanidae, closely affiliated with *Ootitan* and *Nanotitan*. *Gigatitan*, is terms of mass, would have been one of the largest airborne insects, with many specimens indicating powerful wings. They had weak and small hindlimbs, which would have not been ideal for large leaps. *Gigatitan*, like many Titanopterans, had elongated mandibles, and aired with the weaker hindlegs, gives insight into how this insect hunted.

Gigatitan was a likely arboreal ambusher; gaining a position high in the trees in wait for smaller animals to move close for the insect to attack. *Gigatitan* likely attacked *Longisquama*and other invertebrates and small vertebrates from the Madygen.

## Paleoecology

*Gigatitan* is among the 1500 insect fossils of the Madygen Formation. During the Triassic, the Madygen was a heavily-forested region characteristic of many curving lakes that culminate into one lake source, with many smaller swamps where many rivers connected.

## Vocalizations

*Gigatitan* possessed the structures on their wings that create the characteristic cricket chirp today. The forewings bore prominent regions which were corrugated. During strigulation, the animal would have produced a type of call or song, likely deeper and louder due to the insects massive size. Below is what a reconstructed call might have sounded like:

## References

* https://en.wikipedia.org/wiki/Gigatitan
* Gigatitan - The Titanopteran Terror
Edestus

Credit: Julio Lacerda.

*Edestus* is an extinct genus of eugeneodont that lived worldwide from the Late Devonian to the Late Carboniferous.

## Description

All *Edestus* are known from their teeth. The largest of the genus, *Edestus giganteus*, could grow up to 6 meters (20 feet), around the size of a great white. Because of how their jaws look, *E. giganteus* is often dubbed the "scissor-tooth shark". The genus has a history of chimera specimens.

## Paleobiology

### Teeth

*Edestus* grew it's teeth like the closely-related *Helicoprion*, and unlike modern sharks: in brackets, not shedding when worn. In the jaws of *Edestus*, a single row occurs, appearing like a large pair of pinking shears. Each species has a distinctive bracket curvature and size.

*E. giganteus* is known from a single set of teeth, now housed at AMNH. From these, research suggests they did not shed worn or broken teeth, instead growing new ones on the gums near the back of their mouths, pushing older teeth to the tip of the jaws. This method is peculiar, and it's particular function is yet-unknown.

### Diet

Initially, analysis on *Edestus* teeth presumed these animals were carnivorous, due to their sharp and serrated nature. Until a more complete specimen is found, how they captured, ate and even their appearance is pure speculation based on close ancestors. *Edestus giganteus* was among the apex predators of their oceans, but how they captured prey is hard to determine. However, research by Wayne M. Itano in 2015 on *E. minor* teeth wear patterns in Texas deposits discovers they likely thrashed at prey vertically to disarm, cripple, slash and dismember prey. *E. giganteus* most likely did the same. Thee methods would be unique amongst the animal kingdom. The examination of tooth wear by Itano also revealed *Edestus* preyed upon rough-skinned animals, though, what kind is unknown.

## Species

* *E. crenulatus?*
* *E. giganteus*
* *E. heinrichi*
* *E. karpinskii?*
* *E. minisculus?*
* *E. minor*
* *E. minsculus?*
* *E. mirus*
* *E. newtoni?*
* *E. serratus?*
* *E. triserratus?*
* *E. vorax*

## Etymology

*Edestus* derives from the Greek "edeste", "to devour". This references how large some *Edestus* teeth are.

## References

* https://paleobiodb.org/classic/basicTaxonInfo?taxon\_no=34453
* https://en.wikipedia.org/wiki/Edestus
* >http://fossilworks.org/bridge.pl?a=taxonInfo&taxon\_no=352986
Cretaceogekko

*Cretaceogekko* is an extinct genus of gecko that lived in Myanmar during the Late Cretaceous.

## Description

*Cretaceogekko* bore tiny lamellae on pads on its feet that allowed it and most modern geckos to climb on vertical surfaces. It is one of the oldest known geckos that has ever existed. It is known from a single partial specimen consisting of a foot and a partial tail. It was discovered in 2001 in Hukawng Valley and named by Arnold and Poinar (2008). *Cretaceogekko* has a striped pattern that was likely for camouflage.

## References

https://en.wikipedia.org/wiki/Cretaceogekko
Cordaticaris

Credit: Joschua Knuppe.

*Cordaticaris* is an extinct genus of hurdiid that lived in China during the Middle Cambrian.

## Description

*Cordaticaris* is known from a large triangular carapace and features that show a large variety of feeding styles. The carapace seen from above is shaped like a heart with pointed ends and the inner ornament curving down around the limbs and mouth. The appendages on the face are equipped with nine blade-like endites, which includes seven subequal elongate endites, one node-adorning peytoia-like mouth cone, and a trunk covered with rows of setal structures.

## Paleoecology

*Cordaticaris* lived in the Zhangxia Formation, which the hurdiid diversifies the known Cambrian ecosystem.

## References

https://www.sciencedirect.com/science/article/abs/pii/S0031018220303928
ERV-Fc

Contamination map of ERV-Fc.

ERV-Fc is a type of ERV, genus, or family of retrovirus that spread worldwide from the Oligocene to the Early Miocene.

## Description

This virus was active and extremely infectious during a period of 15 million years: from the Oligocene to the Early Miocene. ERV-Fc infected via a mechanism in the genome, and would jump species 20+ times. Apparently, the virus spread across the globe, only missing Australia and Antarctica. After it's 15-million-year reign, ERV-Fc went extinct likely due to it's hosts gaining an inherited resistance. Inactive and damaged genomes still inhabit the genomes of many mammals in the modern day, however, spanning many orders that includes primates such as humans. Because of this, researchers have been able to track interspecies jumps, having gaps in the genome where the original host animal has no extant members. These were timed with a molecular clock in extant descendants.
Dissimulodorylus

*Dissimulodorylus* is a possibly extinct genus of army ant that lived in the Baltic during recent times.

## History

*Dissimulodorylus* was first proposed by Sosiak et al. (2023) but later retracted because the holotype specimen, MCZ PALE-846, was found to be of recent age and not of Eocene antiquity, as originally assumed by the describing team. Shortly after publication, authors were contacted by Brendon E. Boudinot and Dmitry  A. Dubovikoff, who indicated that they were aware of several recent *Dorylus* included in copal and intermixed with genuine Eocene-aged Baltic amber. Additionally, the holotype falls within the timeframe when these specimens were mixed; the 1920s through 1930s. As well, the University of Jena did not provide labels for their Baltic amber collections during the working process. Another specimen similar to *Dissimulodorylus* was slide mounted, increasing the author's confidence in an Eocene age. In response to notice from the two researchers, they compiled data on sure Tanzanian and Zanzibar copal, which matched the holotypic specimen and thus confirming a recent date. These specimens were given to another specialist without identification labels to ensure genuine results. The provenance of the specimen remains unclear and the ant itself was compared with extant *Dorylus* specimens. They concluded that their genus should not be synonymized as it may document a recent extinction in the region or an as-of-yet undiscovered extant species.

## Description

It was initially distinguished through the lacking of eyes, a complete pronotomesopleural suture, a high-positioned propodeal spiracle on the propodeum and one waist segment. These place it in Dorylinae closest to *Dorylus*, which itself is unlike this taxon through a pygidial field that is impressed and the lacking of an overhanging triangular frontal lobe that is dorsoventrally flat. Post-retraction, the specimen's morphology was revisited and determined to remain a distinct genus, although junior synonymy seems appropriate. As such it is either a recent extinction, documented in some other copal specimens, or undiscovered and extant. Prior to retraction, only one other army ant fossil was noted, and their new genus was thought to have been the oldest army ant as well as unexpected diversity within an extinct ghost lineage.

## References

* https://royalsocietypublishing.org/doi/10.1098/rsbl.2023.0059
* https://www.antwiki.org/wiki/Dissimulodorylus
* https://rs.figshare.com/collections/Supplementary\_material\_from\_An\_Eocene\_army\_ant\_/6292512
Chuandongocoelurus

*Chuandongocoelurus* is an extinct genus of carnivorous tetanuran theropod dinosaur that lived in China during the Middle Jurassic.

## History

It was named by He (1984), meaning "the primitive Chuandong hollow tail one" in reference to its location, the genus Coelurus ("hollow tail") and its age, respectively. The holotype is thighbone CCG 10010, 201 millimeters long. Also assigned (under the same number) are vertebrae, pelves and parts of the hindlimb and may be a part of the same individual. Unfused neurocental sutures indicate immaturity at death. A second specimen is CCG 20011, a cervical series from a much larger individual. In 2012, however, they were concluded to be different genera that are probably not closely related. It was closer related to *Elaphrosaurus*. discovered from the Lower Shaximiao Formation, finding an age from the Bathonian to the Callovian.

## Classification

He (1984) placed it in Coeluridae, which was then a wastebasket for small dinosaur varieties. David Bruce Norman (1990) considered it an indeterminate theropod, but Benson (2008, 2010) and Benson et al. (2010) suggest it is sister to *Monolophosaurus* in Megalosauria or just outside of such in Tetanurae. Cerrano et al. recover it being outside of Megalosauroidea. Rauhut and Pol (2019) recover:

## References

https://en.wikipedia.org/wiki/Chuandongocoelurus
IGM 100/1126

Scan of the vestibular endocast.

IGM 100/1126, formerly IGM 100/1005 and IGM 100/1128, is an unnamed genus of Troodontid Dinosaur that lived in Mongolia during the Late Cretaceous.

## Description

IGM 100/1126 is known from a mostly complete skeleton, including skull. The specimen was discovered in the Zos Wash beds within the Campanian-aged section of the Djadokhta Formation. It is currently on long-term loan to the American Museum of Natural History.

## References

* https://theropoddatabase.com/Troodontidae.htm#Troodontidae
* Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247
CM 3452

Credit: WitmerLab at Ohio University.

CM 3452 is an unnamed genus of Sauropod that lived in North America during the Late Jurassic.

## Description

This specimen is articulated, known from a complete skull and undescribed postcrania.

## Phylogyny

In all 4 analysis recovered by Tschopp, Mateus, and Benson (2015) as the sister to *Kaatedocus* + *Barosaurus*, but since the number of differences it possesses from *Diplodocus*, *Kaatedocus*, and *Barosaurus*, it was not named within the paper.

## References

* https://en.wikipedia.org/wiki/Diplodocidae
* https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393826/
* https://sketchfab.com/3d-models/diplodocus-sub-adult-sauropod-dinosaur-skull-49dfa58ca38447b583d6a7afcab539ce
Buru

The buru, alternatively as bura, buro or bru, is a reportedly extinct cryptozoological creature that lived in India up to ~1947.

## History

Buru are said to be aquatic creatures and are the foundational myth of the Apatini people. From 1945-1946, James Phillip Mills and Charles Stonor gathered information about the creature. The elders spoke of their forefathers migrating to Ziro valley, which was mostly covered by marshes and inhabited by burus. They decided to settle in the area because of fertility and good climate, but they would sometimes confront the creatures. Because of this, they decided to drain the marshes to rid of the burus and give land to cultivate rice. They said most died due to the drainage, but some went underground and into the springs. Professor Christopher von Furer-Haimendorf (1947) was also told about the buru. However, it was sad the animals had became extinct in the valley at that time. The final sighting was by a young woman, who had reportedly seen an individual while she was illustrating water at the springs. She told her father what had happened, and the village filled the springs with rocks and clay.

The buru is crocodilian-like.

## References

https://en.wikipedia.org/wiki/Buru\_(legendary\_creature)
Dinosaur Park Formation quetzalcoatline

The Dinosaur Park Formation quetzalcoatline is an indeterminate genus of possible quetzalcoatline azhdarchid pterosaur that lived in Montana during the Late Cretaceous.

## History

A partial skeleton of an azhdarchid pterosaur possibly related to *Cryodrakon* was first announced in 2021 through Denver Fowler, continuing into 2022. The partial skeleton, prepared by Deanna Neff, is known from a phalanx II/III, phalanx III, part of the metacarpals, fragments of the ulnar-radial region of the forearm and three cervicals near to the base. The phalanx II or III is comparatively and unusually short; Fowler is sure that the elements are phalanges, but discussion through Facebook shows that they lack ginglymoid ends, so the identification as part of the azhdarchid skeleton is malleable. Ligament pits are very clear on the wing tips, which is another strange trait for pterosaurs. Fowler suggests that, since it is from a multi-taxic bonebed, other identifications may be possible, but it's thin walls suggest that it is a pterosaur.

## References

* https://twitter.com/AshPoust/status/1613606075877707776
* https://twitter.com/df9465/status/1613601424151314432
Cryodrakon

*Cryodrakon* is an extinct genus of Azhdarchid pterosaur that lived in Canada during the Late Cretaceous

## Description

*Cryodrakon* measures about 6 meters tall, with a 5 meter wingspan. *Cryodrakon* had a pointy beak, presumably for snatching any animal small enough to slid down the animals esophagus. *Cryodrakon* was covered in a light, downy filament.

## Notable Specimens

* TMP 1992.83: Consisting of vertebrae, ribs, a humerus, and metatarsals.
Equus senezensis

NHMLSZ30 cranium.

*Equus senezensis* is an extinct species of horse that lived in France during the Early Pleistocene.

## History

*E. senezensis* was initially classified as *E. s. senezensis*.

## Description

It is intermediate in size of *Equus stenonis* and *Equus stehlini*/*altidens*, with morphology that lies within the range of *E. stenonis*. Overall, its morphology shares traits that are intermediate of multiple species and thus warrants distinction. The mc3s, mt3s and the 1ph3s are wider than *E. altidens*.

## Classification

*E. senezensis* was first classified as *Equus stenonis senezensis* as part of a roster of subspecies belonging to that taxon and then briefly reclassified as *Allohippus stenonis senezensis*. However, Cirilli et al. (2021) suggest that the morphology of the specimen warrant standing as a distinct species. It, *E. stenonis* and *E. stehlini* bear close relations, which have led to historical misclassification. Yet, it appears that the latter diverged from *E. senezensis*. Prat (1964) originally named it as a subspecies of *E. stenonis*, assigning a left P2-M3 and 2 mc3s as lectotype.

## Paleoecology

*E. senezensis* lived in the French Plio-Pleistocene locality of Senèze, where it was contemporaneous with *Equus major* 2.2-2 million years ago (during the Early Pleistocene).

## References

1. ↑ 1.0 1.1 1.2 1.3 https://www.sciencedirect.com/science/article/abs/pii/S0277379121003620
2. ↑ 2.0 2.1 https://www.sciencedirect.com/science/article/abs/pii/S0047248421001032
3. ↑ https://www.researchgate.net/profile/Omar-Cirilli/publication/358751878\_EQUUS\_STEHLINI\_AZZAROLI\_1964\_PERISSODACTYLA\_EQUIDAE\_A\_REVISION\_OF\_THE\_MOST\_ENIGMATIC\_HORSE\_FROM\_THE\_EARLY\_PLEISTOCENE\_OF\_EUROPE\_WITH\_NEW\_INSIGHTS\_ON\_THE\_EVOLUTIONARY\_HISTORY\_OF\_EUROPEAN\_MEDIUM-\_AND\_SM/links/6213d8fd08bee946f3943cb4/EQUUS-STEHLINI-AZZAROLI-1964-PERISSODACTYLA-EQUIDAE-A-REVISION-OF-THE-MOST-ENIGMATIC-HORSE-FROM-THE-EARLY-PLEISTOCENE-OF-EUROPE-WITH-NEW-INSIGHTS-ON-THE-EVOLUTIONARY-HISTORY-OF-EUROPEAN-MEDIUM-AND.pdf
4. ↑ https://www.mdpi.com/2079-7737/11/9/1258
Erythrovenator

Credit: Márcio L. Castro.

*Erythrovenator* is an extinct genus of basal theropod dinosaur that lived in Brazil during the Late Triassic.

## History

*Erythrovenator* means "red hunter", based on the colour of the remains. The species epithet references the nearby Rio Jacuí river.

## Description

The holotype is CAPPA/UFSM 1057 - a proximal femoral fragment. The femoral head is strongly concave in the lower edge, has a rounded inner edge and an anterolateral tuber that is distinct. All of these differentiate *Erythrovenator* as a dinosaur. This left femur is approximately 190 millimeters in length, and was found in an assemblage no other dinosauromorphs are known from. The anteromedial and posteromedial tubers are small, the posteromedial is quite different from the folded anteromedial in most theropods. On the femoral head, a thin ridge rests on the medial portion (with a raised scar on the lateral). The latter few are very similar to *Buriolestes*. The dorsolateral trochanter isn't there, which is distinct from most Triassic dinosaurs. However, the anterior trochanter is a distinct pyramid which is offset because of a cleft. That last part is similar to neotheropods and some Silesauridae. There is no distinct trochanteric shelf, but there is a anterior trochanter with a plate-like medial extension.

## Classification

*Erythrovenator* is a most basal theropod according to phylogenetic analysis, based on the anterior trochanter's structure. This would make it the oldest theropod, and one of the few from Triassic Brazil. Potentially older dinosaurs include *Eodromaeus*, *Nhandumirim*, *Guaibasaurus* and various Herrarasauridae. However, not all of those genera are considered theropods 100% of the time. *Lepidus* and *Camposaurus*, both theropods, may be a similar age to *Erythrovenator*.

## Paleoecology

Erythrovenator lived in the Canderlária Formation, of which was dominated by *Siriusgnathus*. Aside from *Erythrovenator*, no other dinosauromorphs are known from this locality (which likely corresponds with the *Riograndia* Assemblage Zone. The specimen was discovered from the Norian/Late Carnian Niemeyer Site in the Candelária Sequence of the Santa Maria Supersequence.

## References

* https://en.wikipedia.org/wiki/Erythrovenator
Burkesuchus

*Burkesuchus* is an extinct genus of basal mesoeucrocodylian that lived in Chila during the Late Jurassic.

## Description

*Burkesuchus* was noticeably small, at an estimated maximum length of 70 centimeters. The cranium is dorsoventrally depressed and transversely wide posteriorly, distinguished by a posteroventrally-flexed wing-like squamosal. A well-defined longitudinal groove runs with the lateral edge of the postorbital and squamosal, which indicates an anteroposteriorly-extensive upper earlid.

## Classification

Phylogenetic analysis places Burkesuchus as a basal Mesoeucrocodylia. This expands the lacking record of non-pelagic members in this clade in the Jurassic Period. Together with *Batrachomimus*, supports that South America represented a cradle for derived crocodyliforme evolution in the Late Jurassic.

## Reference

* https://www.nature.com/articles/s41598-021-93994-z
* https://indianexpress.com/article/technology/science/modern-crocodiles-grandfather-chile-fossil-7422726/
* https://www.reuters.com/lifestyle/science/modern-crocodiles-grandfather-150-million-years-old-discovered-chile-fossil-2021-07-23/
* https://blog.everythingdinosaur.co.uk/blog/\_archives/2021/07/26/newly-described-prehistoric-crocodile-from-southern-chile.html
* https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8298593/
Densastroma

*Densastroma* is an extinct genus of coral that lived in North America, Europe and Russia during the Silurian to the Devonian.

## Distribution

*Densastroma* lived throughout the Silurian to the Devonian throughout Canada, the United States, European countries like Latvia, Ukraine and Sweden, Russia and the United Kingdom.

## References

https://paleobiodb.org/classic/basicTaxonInfo?taxon\_no=3370
Celtedens

Credit: Kana-hedi on DeviantArt.

*Celtedens* is an extinct genus of amphibians that lived in Europe from the Late Jurassic to the Late Cretaceous.

## Description

*Celtedens* likely had a ballistic tongue, based on new finds from its relative *Yaksha.*

## Classification

this phylogeny was recovered by Daza et al (2020):

## References

* https://en.wikipedia.org/wiki/Celtedens
* *Yaksha*
Edaphodon

Credit: HodariNundu on DeviantArt.

*Edaphodon* is an extinct genus of rabbitfish that lived in the Northern Hemisphere and New Zealand from the Late Cretaceous to the Pliocene.

## Description

*Edaphodon* had a cartilaginous skeleton, known mainly from fragmentary specimens that includes teeth and fin spines. These remains is similar to extant rabbitfish in appearance, feeding opportunistically on small sea floor animals with six tooth plates (one pair on the upper, and two on the lower jaw). Additionally, *Edaphodon* likely layed eggs in a leathery pouch, however this is only assumed. The fish had a large sloping head that overlaps a small mouth. *Edaphodon* would likely have drifted along the seabed like modern terrestrial grazers. *Edaphodon* was closest related to *Ischyodus*, with *E. kawai* possibly belonging to the latter genus.

## References

* *E. agassizi*
* *E. antwerpiensis*
* *E. bucklandi*
* *E. eyrensis*
* *E. hesperis*
* *E. kawai*
* *E. laqueatus*
* *E. leptognathus* (not formally classified)
* *E. minor*
* *E. mirabilis* (not formally classified)
* *E. mirificus*
* *E. sedgwicki*
* *E. smocki*
* *E. stenobryus*
* *E. tripartitus*