Pycnonemosaurus

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Pycnonemosaurus
Temporal range: Late Cretaceous, Campanian
Pycnonemosaurus nevesi skeletal simple.jpg
Skeletal restoration showing known material
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Abelisauridae
Clade: Furileusauria
Genus: Pycnonemosaurus
Kellner & Campos, 2002
Species:
P. nevesi
Binomial name
Pycnonemosaurus nevesi
Kellner & Campos, 2002
Synonyms
  • Pycnoneosaurus nevesiPaul, 2010 lapsus calami

Pycnonemosaurus (meaning 'dense forest lizard') is a genus of carnivorous theropod dinosaur that belonged to the family Abelisauridae. It was found in the Upper Cretaceous red conglomerate sandstones of the Cachoeira do Bom Jardim Formation, Mato Grosso, Brazil, and it lived during the Campanian stage of the Late Cretaceous period.

Contents

Discovery and naming

The type species, Pycnonemosaurus nevesi, was scientifically described by Kellner and Campos in 2002. [1] [2] The only known specimen (DGM 859-R) was found in a red conglomeratic sandstone at the Jangada Roncador locality (then known as Fazenda Roncador), in Mato Grosso State that is exposed close to Paulo Creek, which is currently referred to the Cachoeira do Bom Jardim Formation. During 1952-1953, Llewellyn Ivor Price visited a farm named "Roncador" in the state of Mato Grosso and collected several dinosaur bones. These remains were found by the owner of the farm, Max de Barros Erhart, and his hired workers at the Paulo Creek site. The most important specimen found was the incomplete skeleton of a large abelisaurid theropod, which was found near several titanosaurid sauropod bones. [2] [3]

Pycnonemosaurus nevesi was named from the Greek word pycnós meaning dense, némos meaning pastures and woods, and saûrus meaning reptile or lizard. This naming was an allusion to Mato Grosso State, where the remains were found. The specific name was named after the late Dr. Iedo Batista Neves, who passed in 2000, who encouraged the pursuit of paleontological studies, particularly of Alexander Kellner. [2]

Description

Size comparison of Pycnonemosaurus (dark green) with other related carnotaurins Carnotaurini sizes updated.png
Size comparison of Pycnonemosaurus (dark green) with other related carnotaurins

Thus far, the remains of Pycnonemosaurus have been fragmentary. No elements were well preserved, and the bone surface is well abraded that indicates the elements were partially exposed at the discovery location before being collected. [2] The type specimen, housed at the Earth Sciences Museum, Rio de Janeiro, consists of five incomplete teeth, parts of seven caudal vertebrae, the distal part of a right pubis, a right tibia, and the distal articulation of the right fibula. The small pubic foot and hatchet-shaped cnemial crest of the tibia distinguishes this species within the abelisaurs. The caudal vertebra has distinct abelisaurid features, such as a fan-shaped transverse process and a cranial projection. However, these awl-like projections are somewhat unlike related abelisaurids, such as Aucasaurus , in that they diminish more towards the distal caudals. All remains were found associated and are presently regarded as belonging to the same individual. [2]

Life restoration Pycnonemosaurus restoration 2020.jpg
Life restoration

Initial size estimates put the animal at 7 metres (23 ft) in length and 1.2 tonnes (1.3 short tons) in weight, [1] but later analyses have found that it was likely larger, being about 8.9 metres (29.2 ft) long. [4] This new size estimate currently makes Pycnonemosaurus the largest formally described member of the Abelisauridae thus far. Another estimation gave a length of 9 metres (29.5 ft) and a weight of 3.6 tonnes (4.0 short tons). [5] later estimates offered an estimate of 8.8 metres (28.9 ft) and 3.6 tonnes (4.0 short tons) of weight. [6] But in 2024 Gregory s Paul give's a smart estimation with 7 metres (23 ft) in length and 1.8 tonnes (2.0 short tons)in weight, [7]

Classification

The following cladogram follows an analysis of 2021 during the description of Llukalkan . [8]

Abelisauridae

Paleoecology

Pycnonemosaurus is the best known abelisaurid from Brazil, where most theropod material is presently rare besides preserved teeth and footprints. Even though only a few species are known from Brazil, it is one of the most informative countries concerning the Lower Cretaceous period. Initially, the deposits in which this dinosaur was found were assigned to the Bauru Group, and later more specifically to the Cambambe Formation, with a possible temporal range spanning from the Campanian to the Maastrichtian stages. [2] [9] [10] However, these deposits have since been reassigned to the Campanian-aged Cachoeira do Bom Jardim Formation. [11] This formation is believed to have been deposited in a semi-arid climate, representing the intermediate parts of alluvial fans. [3] [12]

Pycnonemosaurus was a predator, preying on mid-sized sauropodomorphs, small crocodylomorphs, and dromaeosaurs. Its teeth were small yet sharp, and were used to get a hold of struggling prey as the abelisaur shook and tore them apart. [2]

See also

Related Research Articles

<i>Abelisaurus</i> Extinct genus of dinosaurs

Abelisaurus is a genus of predatory abelisaurid theropod dinosaur alive during the Late Cretaceous Period (Campanian) of what is now South America. It was a bipedal carnivore that probably reached about 7.4 metres in length, although this is uncertain as it is known from only one partial skull.

<i>Xenotarsosaurus</i> Extinct genus of dinosaurs

Xenotarsosaurus is a genus of abelisaurid theropod dinosaur that lived during the Late Cretaceous of Argentina.

<i>Aucasaurus</i> Extinct genus of dinosaurs

Aucasaurus is a genus of medium-sized abelisaurid theropod dinosaur from Argentina that lived during the Late Cretaceous of the Anacleto Formation. It was smaller than the related Carnotaurus, although more derived in some ways, such as its extremely reduced arms and almost total lack of fingers. The type skeleton is complete to the thirteenth caudal vertebra, and so is relatively well understood, and is the most complete abelisaurid yet described. However, the skull is damaged, causing some paleontologists to speculate that it was involved in a fight prior to death.

<span class="mw-page-title-main">Abelisauroidea</span> Extinct clade of dinosaurs

Abelisauroidea is a diverse superfamily of ceratosaurian dinosaurs, typically regarded as a Cretaceous group, though the earliest abelisaurid remains are known from the Middle Jurassic of Argentina and possibly Madagascar. Possible Abelisauridae remains were also discovered in Late Jurassic Tendaguru Beds in Tanzania.

<i>Ilokelesia</i> Extinct genus of reptiles

Ilokelesia is an extinct genus of abelisaurid theropod, preserved in the layers of the earliest Late Cretaceous of the Huincul Formation, Neuquén Group, located near Plaza Huincul, Neuquén Province, Argentina. The specimen, consisting of very fragmentary elements of the skull and the axial and appendicular skeleton, was described by Rodolfo Coria and Leonardo Salgado in late 1998.

<i>Quilmesaurus</i> Extinct genus of dinosaurs

Quilmesaurus is a genus of carnivorous abelisaurid theropod dinosaur from the Patagonian Upper Cretaceous of Argentina. It was a member of Abelisauridae, closely related to genera such as Carnotaurus. The only known remains of this genus are leg bones which share certain similarities to a variety of abelisaurids. However, these bones lack unique features, which may render Quilmesaurus a nomen vanum.

<i>Ekrixinatosaurus</i> Extinct genus of dinosaur

Ekrixinatosaurus is a genus of abelisaurid theropod which lived approximately 100 to 97 million years ago during the Late Cretaceous period. Its fossils have been found in Argentina. Only one species is currently recognized, Ekrixinatosaurus novasi, from which the specific name honors of Dr. Fernando Novas for his contributions to the study of abelisaurid theropods, while the genus name refers to the dynamiting of the holotype specimen. It was a large abelisaur, measuring between 6.5 and 8 m in length and weighing 800 kg (1,800 lb).

<span class="mw-page-title-main">Carnotaurinae</span> Extinct subfamily of reptiles

Carnotaurinae is a subfamily of the theropod dinosaur family Abelisauridae. It includes the dinosaurs Aucasaurus, Carnotaurus. The group was first proposed by American paleontologist Paul Sereno in 1998, defined as a clade containing all abelisaurids more closely related to Carnotaurus than to Majungasaurus.

<span class="mw-page-title-main">Carnotaurini</span> Extinct tribe of dinosaurs

Carnotaurini is a tribe of the theropod dinosaur family Abelisauridae from the Late Cretaceous period of Patagonia. It includes the dinosaurs Carnotaurus sastrei; the type species, Aucasaurus garridoi, and Abelisaurus comahuensis. This group was first proposed by paleontologists Rodolfo Coria, Luis Chiappe, and Lowell Dingus in 2002, being defined as a clade containing "Carnotaurus sastrei, Aucasaurus garridoi, their most recent common ancestor, and all of its descendants."

<i>Skorpiovenator</i> Extinct genus of dinosaurs

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<i>Rahiolisaurus</i> Genus of abelisaurid dinosaur from the Late Cretaceous period

Rahiolisaurus is a genus of abelisaurid theropod dinosaur which existed in India during the Late Cretaceous period. It was described in 2010, based on fossils recovered from the Lameta Formation in the Indian state of Gujarat. These fossils include elements from at least seven different individuals and are believed to have been from the Maastrichtian stage, sometime between 70 and 66 million years ago, making it one of the last non-avian dinosaurs known in the fossil record. Despite representing a variety of different growth stages, all recovered fossils from the locality indicate a single species, the type species Rahiolisaurus gujaratensis.

<i>Eoabelisaurus</i> Extinct genus of dinosaurs

Eoabelisaurus is a genus of abelisaurid theropod dinosaur from the Lower Jurassic Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Argentina, South America. The generic name combines a Greek ἠώς, (eos), "dawn", with the name Abelisaurus, in reference to the fact it represents an early relative of the latter. Only one species is currently recognized, E. mefi; the specific name honours the MEF, the Museo Paleontológico "Egidio Feruglio", where discoverer Diego Pol is active. It is characterized by reduced forelimb proportions that show primitive characteristics of the Abelisauridae family.

<i>Arcovenator</i> Extinct genus of dinosaurs

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<span class="mw-page-title-main">Majungasaurinae</span> Extinct subfamily of reptiles

Majungasaurinae is a subfamily of large carnivorous theropods from the Upper Cretaceous, found in Madagascar, India, and France. It is a subgroup within the theropod family Abelisauridae, a Gondwanan clade known for their thick and often horned skulls and vestigial arms. The two subfamilies of Abelisauridae are Carnotaurinae, best known from the South American Carnotaurus, and Majungasaurinae, consisting of Madagascar’s Majungasaurus and its closest relatives. Their ancestors emerged in the Middle Jurassic, and the clade lasted until the Upper Cretaceous.

<span class="mw-page-title-main">Timeline of ceratosaur research</span>

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<i>Viavenator</i> Extinct genus of dinosaurs

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<span class="mw-page-title-main">Furileusauria</span> Clade of abelisaurid theropod dinosaurs

Furileusauria is an extinct clade of derived abelisaurid dinosaurs only known from South American fossil remains. They represent some of the largest members of the Abelisauridae, with an average length of 7.1 ± 2.1 m (23.3 ± 6.9 ft). The clade is defined as the most inclusive clade containing Carnotaurus sastrei but not Ilokelesia aguadagrandensis, Skorpiovenator bustingorryi, or Majungasaurus crenatissimus.

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<i>Spectrovenator</i> Extinct genus of reptiles

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<i>Kurupi itaata</i> Genus of dinosaur from the Late Cretaceous period

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References

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  5. Molina-Pérez & Larramendi (2016). Récords y curiosidades de los dinosaurios Terópodos y otros dinosauromorfos. Barcelona, Spain: Larousse. p. 257.
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