|
|
Post by Gorilla king on Jul 27, 2021 11:36:51 GMT -5
Brontornis is an extinct genus of either anseriforms or giant flightless terror birds (Phorusrhacidae) that inhabited Argentina during the Early to Middle Miocene.[1] Certainly the heaviest of the Phorusrhacidae family, and the birds from the Americas as a whole, it is one of the largest birds that has ever existed.[2]
Description
Brontornis had an estimated height of 2.8 m (9 ft 2 in) and its body mass is estimated between 350 and 400 kg (770 and 880 lb), making it the heaviest terror bird but slightly behind Kelenken in height and skull length. It may have been about 1.75 m (5 ft 9 in) tall at the back. These measures would make Brontornis the fifth-heaviest bird found thus far, after Vorombe titan, Dromornis stirtoni, Aepyornis maximus, and Pachystruthio dmanisensis.[2]
A comparison of the tarsometatarsi of two B. burmeisteri specimens, FM-P13259 and MLP-91 (lectotype), both coming from the same geographical region and geological formation, shows them as not to present any anatomical differences, apart from size, where in the first is around one third smaller than the second. The idea is that they are examples of intraspecific variation, possibly sexual dimorphism. There is the possibility that they represent two species.[2]
Discovery
Fossils of the terror bird have been found in the Santa Cruz and Monte León Formations in Argentina.[3] It is known from bones, mainly of the legs and feet but also portions of some skulls and backbone, found in several localities of Santa Cruz Province. It coexisted with some slightly smaller and more active phorusrhacids like Phorusrhacos.
Classification
Recent work has cast doubt on the hypothesis that Brontornis is a phorusrhacid. Brontornis may actually represent an anseriform, with other genera traditionally assigned to Brontornithinae (Physornis and Paraphysornis) being true phorusrhacids. The subfamily containing the latter two had been proposed to be renamed to Physornithinae, with Physornis fortis as the type species. If these conclusions are valid, this would mean that there are three groups of giant basal anseriformes, in chronological order of divergence: the gastornithids (Gastornis and kin), Brontornis, and finally the mihirungs of Australia.[4][5]
However, other analyses have also argued that Brontornis exhibits thoracic vertebrae diagnostic of phorusrhacids, supporting its placement within that group.[6]
In a 2021 paper by Agnolin found Brontornis to a gastornithiform sister to the mihirungs.[7]
en.m.wikipedia.org/wiki/Brontornis
|
|
|
|
Post by Gorilla king on Jul 27, 2021 11:39:34 GMT -5
PREHISTORIC FAUNA BY ROMAN UCHYTEL Brontornis burmeisteri
Brontornis burmeisteri (†Brontornis Moreno & Mercerat, 1891)
Class: Aves
Order: ?Anseriformes
Family: Brontornithidae
Time period: lived in the Miocene. (Patagonia,South America)
Size: 280 cm in height, 250 - 400 kg of weight
Typical representative: Brontornis burmeisteri
Brontornis was a genus of giant flightless predatory birds that lived in Patagonia. The only species currently accepted as valid is B. burmeisteri. It has traditionally been placed in the family Phorusrhacidae, nicknamed "Terror Birds" for their large size and predatory lifestyle, and more precisely to the subfamily Brontornithinae, which contained extremely large and very heavyset forms. It is known from bones, mainly of the legs and feet but also portions of some skulls and backbone, found in several localities of Santa Cruz Province.
B. burmeisteri was the second tallest species of phorusrhacid, with a height of around 2.8 m and the heaviest species of phorusrhacid with an estimated weight of 350–400 kg (Alvarenga & Höfling, 2003), making it the third-heaviest bird ever according to current knowledge (after Aepyornis maximus and Dromornis stirtoni), and the most massive land predator of its time and place. Due to its bulk, it probably had a lifestyle between an ambush predator and one that actively chased prey, pouncing on the latter from a hideout and bringing it down by sheer force of attack after a short chase. In attacking prey (but probably not necessarily in a defensive situation, as it was too slow-moving) it most likely was the dominant carnivore of Miocene Patagonia, being able to kill even large animals such as the elephant-like Astrapotherium and in the predatory role being on par with a pack of Thylacosmilus (metatherian sabre-tooth). It coexisted with some slightly smaller and more active phorusrhacids like Phorusrhacos, but apparently became extinct before the appearance of the immense Argentavis, the largest flying bird ever.
Possibly, the fossils described as B. platyonyx represent another species; they are about one-third smaller than the largest Brontornis bones. It is much more likely, however, that they represent sexual dimorphism. In today's hawks and owls, females are usually considerably larger than the males; this prevents overutilization of one size class of prey. It is not known whether phorusrhacid males or females would have been larger, but the fossils of the North American phorusrhacid Titanis also show considerable variation in size, suggesting that there was indeed at least a tendency for differently sized sexes. Some recent work has cast doubt on the hypothesis that Brontornis is a phorusrhacid; according to this research, it seems to actually be an anseriform. The other genera traditionally assigned to the subfamily Brontornithinae (Physornis and Paraphysornis) apparently are true phorusrhacids so the subfamily containing them had been proposed to be renamed Physornithinae, with Physornis fortis as the type. If valid, this would mean that there are three groups of giant basal anseriformes, in chronological order of divergence first the gastornids (relatives of Gastornis) then Brontornis and finally the mihirungs of Australia.
However, a subsequent analysis interprets Brontornis as having adaptations to great weight but exhibiting thoracic vertebrae diagnostic of phorusrhacids, reaffirming its placement within that group.
prehistoric-fauna.com/Brontornis
|
|
|
|
Post by Gorilla king on Jul 27, 2021 11:43:42 GMT -5
PREHISTORIC WILDLIFE
 Name: Brontornis (Thunder bird).
Phonetic: Bron-tor-niss.
Named By: Francisco P. Moreno & Alcides Mercerat - 1891.
Synonyms: Brontornis platyonyx, Rostrornis floweri.
Classification: Chordata, Aves, Cariamae, Phorusrhacidae, Brontornithinae.
Species: B. burmeisteri (type).
Diet: Carnivore.
Size: Up to 2.8 metres tall.
Known locations: Argentina, Santa Cruz Province.
Time period: Miocene.
Fossil representation: Several specimens, usually of the legs and feet, but some vertebrae and skull material are also known.
Brontornis was easily one of the largest of the known South American ‘terror birds’, and as a member of the Brontornithinae it is noted as being one of the most robust in build. Whereas some terror birds could use their speed to run down prey, Brontornis would have been more suited to ambush tactics against larger prey. This would mean staying amongst trees and tall vegetation to hide its profile while prey wandered close enough for a strike.
The heavy build of Brontornis would have been key to its hunting strategy, essentially relying upon brute force to bring its prey down. One reason for this is that without speed to keep pace with its prey it would need to take it down quick before the prey had time to escape. Another is that as a larger bird it would need to eat larger and more powerful prey items to have enough food to survive. This meant a focus upon prey that could have withstood weaker blows necessitating the requirement for the ability to inflict stronger impacts.
Brontornis placement within the Phorusrhacidae has been questioned on the grounds of its similarities with anseriform birds, more specifically like the large flightless birds of Australia such as Dromornis and Bullockornis. However this similarity may actually be a simple case of convergent evolution as studies of the vertebra have since suggested that Brontornis is indeed more like the other phorusrhacids. This also helps to tie in South America’s geographic isolation from the rest of the world during the Miocene.
Further reading
- Catalogue des Oiseaux Fossiles de la Republique Argentine conserves au Musee de la Plata. - Anales del Museo de la Plata 1:1-71 - F. P. Moreno & A. Mercerat - 1891.
- Systematic revision of the Phorusrhacidae (Aves: Ralliformes) - Papéis Avulsos de Zoologia 43 (4): 55–91 - H. M. F. Alvarenga & e. Höfling - 2003.
- Brontornis burmeisteri Moreno & Mercerat, un Anseriformes (Aves) gigante del Mioceno Medio de Patagonia, Argentina. - Revista del Museo Argentino de Ciencias Naturales, n.s. 9, 15-25 - F. Agnolin - 2007.
www.prehistoric-wildlife.com/species/b/brontornis.html
|
|
|
|
Post by Gorilla king on Jul 27, 2021 11:45:55 GMT -5
|
|
|
|
Post by Gorilla king on Jul 27, 2021 11:48:43 GMT -5
Reappraisal on the Phylogenetic Relationships of the Enigmatic Flightless Bird (Brontornis burmeisteri) Moreno and Mercerat, 1891
Abstract and Figures
The fossil record of birds in South America is still very patchy. One of the most remarkable birds found in Miocene deposits from Patagonia is Brontornis burmeisteri Moreno and Mercerat, 1891. This giant flightless bird is known by multiple incomplete specimens that represent a few portions of the skeleton, mainly hindlimb bones. Since the XIX century, Brontornis was considered as belonging to or closely related to phorusrhacoid birds. In contrast to previous work, by the end of 2000 decade it was proposed that Brontornis belongs to Galloanserae. This proposal was recently contested based on a large dataset including both phorusrhacoids and galloanserine birds, that concluded Brontornis was nested among cariamiform birds, and probably belonged to phorusrhacoids. The aim of the present contribution is to re-evaluate the phylogenetic affinities of Brontornis. Based on modified previous datasets, it is concluded that Brontornis does belong to Galloanserae, and that it represents a member of a largely unknown radiation of giant graviportal birds from South America.
www.researchgate.net/publication/349498003_Reappraisal_on_the_Phylogenetic_Relationships_of_the_Enigmatic_Flightless_Bird_Brontornis_burmeisteri_Moreno_and_Mercerat_1891
|
|
|
|
Post by Gorilla king on Jul 27, 2021 11:53:01 GMT -5
|
|
|
|
Post by Gorilla king on Jul 27, 2021 12:00:49 GMT -5
|
|
|
|
Post by oldcyansilverback on Jul 27, 2021 20:36:25 GMT -5
The brontornis is heavily built.
|
|
|
|
Post by Gorilla king on Jul 27, 2021 22:26:05 GMT -5
|
|
|
|
Post by tyrannosaurs on Jul 28, 2021 6:02:41 GMT -5
Brontornis burmeisteri Moreno & Mercerat, a giant Anseriformes (Aves) from the Middle Miocene of Patagonia, Argentina: Resumen Brontornis burmeisteri Moreno & Mercerat, a giant Anseriformes (Aves) from the Middle Miocene of Patagonia, Argentina. Since its original description, Brontornis burmeisteri was considered as closely related to the family Phorusrhacidae (Gruiformes). Brontornis is known only by scarce postcranial remains, fragmentary mandibles and a quadrate bone. All the material comes from the Miocene of Santa Cruz Province, Argentina. A reanalysis of this material indicates that Brontornis may be more properly included within the Anseriformes as a basal member of this group, together with Diatryma and the extinct family Dromornithidae. Its inclusion within the Anseriformes suggests a more complex evolutionary history of the poorly known paleoavifaunas of South America. www.researchgate.net/publication/311483926_Brontornis_burmeisteri_Moreno_Mercerat_a_giant_Anseriformes_Aves_from_the_Middle_Miocene_of_Patagonia_Argentina |
|
|
|
Post by oldcyansilverback on Sept 12, 2021 6:43:46 GMT -5
The brontornis is the predatory bird of the south. Wish there were more accounts of its interaction with the smilodons.
|
|
|
|
Post by Gorilla king on Sept 12, 2021 9:26:00 GMT -5
The brontornis is the predatory bird of the south. Wish there were more accounts of its interaction with the smilodons.
 |
|
|
|
Post by oldcyansilverback on May 13, 2022 4:34:17 GMT -5
/\ Sometimes I wish there were interactions between the brontornis and smilodon populator.
|
|
|
|
Post by Gorilla king on Dec 6, 2022 10:35:02 GMT -5
|
|
|
|
Post by oldcyansilverback on Dec 7, 2022 7:45:37 GMT -5
/\ That is an interesting interaction.
|
|
