Ubirajara jubatus

From Wikipedia, the free encyclopedia
Holotype specimen

"Ubirajara" ("lord of the spear") is an informal genus of compsognathid theropod that lived during the early Cretaceous period in what is now Brazil. The manuscript describing it was available online pre-publication but was never formally published and, as a consequence, both genus and species name are considered invalid and unavailable.[1] It is known by a single species, "Ubirajara jubatus", recovered from the Crato Formation. It was described as the first Gondwanan non-avian theropod dinosaur discovered with preserved integumentary structures. Such proto-feathers, most likely used for display, include slender monofilaments associated with the base of the neck, increasing in length along the dorsal thoracic region, where they would form a mane, as well as a pair of elongate, ribbon-like structures likely emerging from its shoulders.[2] The taxon was informally named in 2020 in a now-withdrawn in-press academic paper. The description caused controversy due to the fossil having been apparently illegally smuggled from Brazil. In July 2022, Germany agreed to return the fossil to Brazil after a legitimate export permit could not be found. The name "Ubirajara jubatus" was removed from ZooBank in November 2022, which means it no longer has any nomenclatural significance.[1]

History of discovery[edit]

Skeletal reconstruction showing known elements

Workers recovered a number of fossils from a chalk quarry located between Nova Olinda and Santana do Cariri. One of the recovered pieces was a chalk plate that had already been split by the workers. Further preparation by a sharp steel pin and X-ray photography revealed the presence of a small theropod skeleton. The specimen, SMNK PAL 29241, was discovered in a layer of the Crato Formation, dating from the Aptian, about 115 million years old. It consists of a partial skeleton lacking the skull, preserved on a slab and counterslab. It consists of nine neck vertebrae, thirteen back vertebrae, two sacral vertebrae, the shoulder girdle, one neck rib, seven dorsal ribs, fifteen belly ribs and the almost complete left arm. Apart from the bones, the fossil also preserves remains of the plumage, skin, granulate structures in the torso, and the keratin sheaths of the hand claws. The skeleton is partially articulated. It represents a juvenile, and possibly male, individual.[3][failed verification]

The genus name "Ubirajara" was erected by Robert S. H. Smyth, David Michael Martill, Eberhard Frey, Hector Eduardo Rivera-Silva and Norbert Lenz in December 2020.[3][failed verification] The generic name means "Lord of the Spear" in the local Tupi language, in reference to the elongate shoulder filaments. The informal specific name, "jubatus," means "maned" in Latin, referring to the preserved integument on its back.[4] However, since the paper was never published, the name "Ubirajara jubatus" is unavailable.[1]

Legal issues[edit]

Officials with the specimen's slab and counterslab during a ceremony after its return to Brazil in 2023

The fossil was acquired in 1995 by the State Museum of Natural History Karlsruhe (SMNK) and moved to Germany after an export permit was allegedly obtained.[3][failed verification][5] The fossils have been alleged to have been illegally imported into Germany out of Brazil in 1995, as Brazilian laws do not allow the removal of fossils from its territory, nor for studies on them to be conducted without the participation of at least one Brazilian scientist.[6][7][8] As a result, Brazilian scientists campaigned for the repatriation of the fossils.[9]

Due to the ethical issues involving the potentially illegal transfer of the fossil from Brazil to Germany, the paper describing the specimen was "temporarily removed" only a few days after being made available online "in press" prior to formal publication.[8][10] The article was later withdrawn in September 2021.[11] The case has been labeled as an instance of scientific colonialism.[12][13][14][15]

In July 2022, following an extensive social media campaign, the SMNK agreed to return the specimen to Brazil after their investigation failed to find legitimate export permits.[16] The specimen has been reported as repatriated in June 2023.[17]

On 18 November 2022, the records of the names "Ubirajara jubatus", as well as their publication records, were removed from ZooBank, and a 2023 review noted that "Ubirajara jubatus" is an unavailable name with no nomenclatural significance, but not specifically a nomen nudum.[1]

It has also been noted that the phylogenetic matrix containing the specimen has never been made available, raising doubts about the claimed affinities of the specimens.[1]

On June 13, 2023, the fossil was repatriated to the claimant country (Brazil), and delivered to the Plácido Cidade Nuvens Paleontology Museum, equipment of the Regional University of Cariri (Urca) [18]


Life restoration

In life, the holotype individual would have been approximately 1 metre (3.3 ft) long.[4]

The describing authors established a unique combination of two traits that in themselves were not unique. The shoulder blade has 81% of the length of the humerus instead of being equally long or much longer, the two prevailing conditions with other compsognathids. The top profiles of the neural spines of the sacral vertebrae are 15% to 27% longer than their bases are long in side view, instead of being much longer as with Mirischia.[3][failed verification]

The granulated structures in the torso were concluded to have been adipocere, corpse wax. They do not show food remains and are therefore unlikely to represent intestines. Also they lack a scale structure. The specimen preserves a "mane" of proto-feathers that ran along its neck and back. Also they covered the arm including the hand up to the claws. This SMF (slender monofilamentous integument) became longer towards the rear, reaching a length of eleven centimetres over the ninth and tenth back vertebrae. These filaments were not branched and had a diameter of about 0.3 millimetre with a hollow core. Skin remains contain a series of nineteen rectangular vertical structures that were interpreted as the follicles of the filaments. Skin muscles would have allowed to erect a mane over the back. Their shrinking in the saline lagoon conditions of the Crato Formation would have caused the mane to have been activated after death, as still shown by the fossil.[3][failed verification]

Unique, 15-centimetre (5.9 in) integumentary structures projected from its sides. The left side shows a pair of flat straight elongated spikes. A similar pair was assumed to have been present on the opposite right side. The upper spike is fifteen centimetres long, the lower one fourteen centimetres. The structures are reinforced by a central sharp longitudinal ridge, 0.1 millimetre wide. Total width is 4.5 millimetres for the upper spike, 2.5 millimetres for the lower with parallel sides which only taper close to the distal end. There is no sign of any ossification. The authors compared this Broad Monofilamentous Integument to those of the standardwing bird-of-paradise. The authors speculate that the ribbon-like shoulder structures might have had display purposes, perhaps being erected in a courtship display. It was also deemed possible that they vibrated and even made a noise. That such a display structure should be present in a juvenile is exceptional. This phenomenon is not known from modern Neornithes but has been reported in Enantiornithes and Zuolong.[3][failed verification] The authors noted that in the more derived group of the Paraves, such structures are largely limited to the tail. They suggested this prevented the display structures to limit the aerodynamic capabilities of these volant species. The non-volant compsognathids would in this respect not be hindered by shoulder spikes. That simple filaments could evolve into complex display structures would be an indication that pennaceous feathers were not evolved for display reasons, contrary to what has been often assumed.[3][failed verification][19]


The holotype was placed in the Compsognathidae family in 2020, as the sister species of a clade formed by Sinosauropteryx and Compsognathus.[4] This phylogeny was criticized since it cannot be properly scientifically tested or replicated at the moment because the data supporting it were never made available.[1]



See also[edit]


  1. ^ a b c d e f Caetano, João Marcus Vale; Delcourt, Rafael & Ponciano, Luiza Corral Martins de Oliveira (March 2023). "A taxon with no name: 'Ubirajara jubatus' (Saurischia: Compsognathidae) is an unavailable name and has no nomenclatural relevance". Zootaxa. 5254 (3): 443–446. doi:10.11646/zootaxa.5254.3.10. PMID 37044710. S2CID 257500264.
  2. ^ Yarlagadda, Tara (15 December 2020). "Paleontologists find tiny, flamboyant dinosaur in ground-breaking discovery". Inverse. Retrieved 2021-09-13.
  3. ^ a b c d e f g Smyth, Robert S. H.; Martill, David M.; Frey, Eberhard; Rivera-Silva, Hector E. & Lenz, Norbert (December 2020). "WITHDRAWN: A maned theropod dinosaur from Brazil with elaborate integumentary structures". Cretaceous Research. doi:10.1016/j.cretres.2020.104686. S2CID 230576514.
  4. ^ a b c Grigorakakis, Panos (2020-12-18). "Bizarre New Dinosaur Sported Mane & Shoulder 'Spears'". Medium. Retrieved 2021-09-16.
  5. ^ "Museu da Alemanha se recusa a devolver fóssil contrabandeado do Ceará, diz sociedade de paleontologia". G1. 10 September 2021.
  6. ^ Pickrell, John (14 December 2020). "A newfound feathered dinosaur sported fuzz and weird rods on its shoulders". Science News. Society for Science & the Public. Archived from the original on 19 December 2020. Retrieved 19 December 2020.
  7. ^ Vogel, Gretchen (18 December 2020). "Chicken-size dino with a furlike mane stirs ethics debate". Science Magazine. American Association for the Advancement of Science. Archived from the original on 19 December 2020. Retrieved 19 December 2020.
  8. ^ a b Greshko, Michael (22 December 2020). "One-of-a-kind dinosaur removed from Brazil sparks backlash, investigation". National Geographic. National Geographic Society. Archived from the original on 23 December 2020. Retrieved 23 December 2020.
  9. ^ "Cientistas fazem campanha para que fóssil de Ubirajara jubatus, novo dino brasileiro, seja repatriado". Folha de S. Paulo (in Portuguese). December 18, 2020. Retrieved December 19, 2020.
  10. ^ Wayback Machine archive of the paper from January 3rd, 2020, showing "TEMPORARY REMOVAL" status
  11. ^ Ortega, Rodrigo Pérez (29 September 2021). "'It's like a second extinction': Retraction deepens legal and ethical battle over rare dinosaur". www.science.org. Retrieved 2021-10-12.
  12. ^ Cisneros, Juan Carlos; Raja, Nussaïbah B.; Ghilardi, Aline M.; Dunne, Emma M.; Pinheiro, Felipe L.; Regalado Fernández, Omar Rafael; Sales, Marcos A. F.; Rodríguez-de la Rosa, Rubén A.; Miranda-Martínez, Adriana Y.; González-Mora, Sergio; Bantim, Renan A. M.; de Lima, Flaviana J.; Pardo, Jason D. (2022). "Digging deeper into colonial palaeontological practices in modern day Mexico and Brazil". Royal Society Open Science. The Royal Society. 9 (3): 210898. Bibcode:2022RSOS....910898C. doi:10.1098/rsos.210898. ISSN 2054-5703. PMC 8889171. PMID 35291323.
  13. ^ Lenharo, Mariana; Rodrigues, Meghie (2022-04-22). "How a Brazilian dinosaur sparked a movement to decolonize fossil science". Nature. Springer Science and Business Media LLC. 605 (7908): 18–19. Bibcode:2022Natur.605...18L. doi:10.1038/d41586-022-01093-4. ISSN 0028-0836. PMID 35459896.
  14. ^ "Institutions in the global north hoard fossils from Brazil, study says". Science. American Association for the Advancement of Science (AAAS). 2022-03-01. doi:10.1126/science.adb1767.
  15. ^ Black, Riley (2022-02-10). "Why Smuggled Fossils Are Hurting Paleontology". Smithsonian Magazine. Retrieved 2022-04-28.
  16. ^ Michael Greshko (2022-07-20). "Unique 'spear lord' dinosaur to be returned to Brazil". National Geographic.
  17. ^ "Germany returns 'stolen' dinosaur fossil to Brazil".
  18. ^ "Fóssil do dinossauro Ubirajara jubatus é repatriado ao Brasil e entregue ao Ceará". Secretaria da Ciência, Tecnologia e Educação Superior (in Brazilian Portuguese). 2023-06-13. Retrieved 2023-06-13.
  19. ^ "'Like nothing seen in nature before': strange dinosaur has scientists enthralled". The Guardian. 15 December 2020. Retrieved 17 December 2020.