Pebasiconcha immanis | |
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Pebasiconcha immanis | |
Scientific classification | |
Kingdom: | |
Phylum: | |
Class: | |
(unranked): | clade Heterobranchia |
Superfamily: | |
Family: | |
Genus: | † Pebasiconcha Wesselingh & Gittenberger, 1999 [2] |
Species: | P. immanis |
Binomial name | |
Pebasiconcha immanis Wesselingh & Gittenberger, 1999 [2] | |
Synonyms | |
Amazoniconcha immanis |
Pebasiconcha immanis is an extinct species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Acavidae. The type locality of Pebasiconcha immanis is the Miocene Pebas Formation in the Colombian and Peruvian Amazonia. [1]
Initially believed to belong to the genus Strophocheilus by Spix (1827), Pebasiconcha is a common fossil shell from western Amazonia. Fieldwork in the autumn of 1991 recovered several exceptionally large specimens, however working conditions of the time did not allow the safe transport of entire specimens, which were subsequently broken and disintegrated. However researchers did manage to take photographs of the complete specimens in situ. Later expeditions also failed to produce intact specimens, with the second visit in 1996 only recovering further shell fragments. During this visit researchers also discovered another well preserved specimen in a shop in Iquitos, Peru, which was however not for sale. While unable to purchase the fossil, photos could be taken. Due to this the description of Pebasiconcha was based on photographs and shell fragments. [2]
The generic name is derived from the Pebas Formation where the fossils have been found and the Latin word "concha" meaning shell. The species name immanis, meaning huge or enormous, was chosen to reflect the animals massive size. [2]
The height of the shell is more than 25 cm (more than 250 mm) making Pebasiconcha one of the largest known land snails. [1] [3] The shell is ovoid in shape with up to six moderately convex whorls. The body whorl has a markedly constricted aperture and a prominent asymmetrical knob on the upper half of the body whorl.The border of the outer lip is neither reflected nor thickened. One specimen with a particularly large mytoid knob may indicate a specimen which either possessed a shell higher than 30 cm or simply a proportionally larger knob than the holotype specimen. [2]
Pebasiconcha lived in the Pebas Mega-Wetlands that covered large parts of northern South America during the middle Miocene period, an environment known for its rich freshwater mollusc fauna. The Mega-Wetland included swamps, marshes, embayments, rivers and forested riverbanks. The terrestrial areas of the wetlands were inhabited by a minimum of two land snails, Pebasiconcha and Orthalicus linteus . While the later most likely inhabited the tree trunks and branches as its extant relatives, Pebasiconcha is hypothesized to have lived in the humid bottom layers. [2]
Tryonia is a genus of freshwater snails in the family Hydrobiidae. This genus is sometimes placed in the family Cochliopidae
Caiman is a genus of caimans within the alligatorid subfamily Caimaninae. They inhabit Central and South America. They are relatively small sized crocodilians, with all species reaching lengths of only a couple of meters and weighing 6 to 40 kg on average.
Stupendemys is an extinct genus of freshwater side-necked turtle, belonging to the family Podocnemididae. It is the largest freshwater turtle known to have existed, with a carapace over 2 meters long. Its fossils have been found in northern South America, in rocks dating from the Middle Miocene to the very start of the Pliocene, about 13 to 5 million years ago. Male specimens are known to have possessed bony horns growing from the front edges of the shell and the discovery of the fossil of a young adult shows that the carapace of these turtles flattens with age. A fossil skull described in 2021 indicates that Stupendemys was a generalist feeder.
Melongena is a genus of sea snails, marine gastropod mollusks in the family Melongenidae, the crown conches and their allies.
Acavidae is a taxonomic family of air-breathing land snails, terrestrial pulmonate gastropod molluscs in the superfamily Acavoidea.
Cochliopidae is a family of small freshwater snails with gills and an operculum, aquatic gastropod mollusks.
Langstonia is an extinct genus of notosuchian crocodylomorph of the family Sebecidae. It lived in the middle Miocene, in the "Monkey Beds" of the Colombian Villavieja Formation. Langstonia was named in 2007 by Alfredo Paolillo and Omar Linares for fossils originally described by Langston in 1965 as Sebecus huilensis. Thus, the type species is L. huilensis.
Balanerodus is an extinct monospecific genus of alligatorid crocodylian. Fossils have been found from the Fitzcarrald Arch in the Peruvian Amazon and the La Victoria Formation of the Honda Group in Colombia and date back to the Friasian and Laventan regional South American land mammal ages of the Middle Miocene.
The Friasian age is a period of geologic time within the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It follows the Santacrucian and precedes the Colloncuran age.
The Colloncuran age is a period of geologic time within the Middle Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Friasian and precedes the Laventan age.
Gryposuchus is an extinct genus of gavialid crocodilian. Fossils have been found from Argentina, Colombia, Venezuela, Brazil and the Peruvian Amazon. The genus existed during the Miocene epoch. One recently described species, G. croizati, grew to an estimated length of 10 metres (33 ft). Gryposuchus is the type genus of the subfamily Gryposuchinae, although a 2018 study indicates that Gryposuchinae and Gryposuchus might be paraphyletic and rather an evolutionary grade towards the gharial.
Onobops is a genus of very small aquatic snails, operculate gastropod mollusks in the family Cochliopidae or in the Hydrobiidae.
Globidentosuchus is an extinct genus of basal caimanine crocodylian known from the late Middle to Late Miocene of the Middle and the Upper Members of the Urumaco Formation at Urumaco, Venezuela. Its skull was very short and robust, with large units of spherical teeth used to break the shells of molluscs as part of its durophagus diet. It is thought to be one of the most basal Caimanines, even sharing some traits with alligatorids.
The Pebas Formation is a lithostratigraphic unit of Miocene age, found in western Amazonia. The formation extends over 1,000,000 square kilometres (390,000 sq mi), including parts of Brazil, Peru, Ecuador and Colombia. It is interpreted as representing the deposits of a lake or series of lakes, formed within the foreland basin of the Andes mountain belt. It is known for its abundant fossil ostracods and molluscs and an unusually diverse group of crocodylians.
Caiman wannlangstoni is an extinct species of caiman that lived in what is now the Amazon Basin and surrounding areas during the Middle and Late Miocene. Fossils of C. wannlangstoni have been found in the Pebas Formation near Iquitos in Peru and include partial skulls and isolated skull bones. Other fossils were uncovered from the Urumaco Formation in Venezuela and the Laventan Honda Group of Colombia. The species was first described in 2015. Features that in combination distinguish C. wannlangstoni from other caimans include a deep snout, a wavy upper jaw margin, a large and upward-directed narial opening, and blunt teeth at the back of the jaws. Based on the sizes of the skulls, its estimated body length is about 211 to 227 centimetres.
Kuttanacaiman is a monotypic genus of extinct caiman represented by the type species Kuttanacaiman iquitosensis. Kuttanacaiman lived in what is now the Amazon basin during the Middle Miocene, approximately 13 million years ago (Ma). The species was named in 2015 on the basis of one nearly complete skull and a second partial skull from the Pebas Formation near Iquitos, Peru. K. iquitosensis is characterized by a short, rounded snout and blunt teeth at the back of its jaws that were likely adapted to crushing freshwater bivalves. Its estimated total body length is 171.2 to 189.1 centimetres.
Gnatusuchus is an extinct genus of caiman represented by the type species Gnatusuchus pebasensis from the Middle Miocene Pebas Formation of Peru. Gnatusuchus lived about 13 million years ago (Ma) in a large wetland system called the Pebas mega-wetlands that covered over one million square kilometers of what is now the Amazon Basin.
Miocochilius is an extinct genus of small notoungulate mammals (typotheres) native to South America. The genus lived during the Middle Miocene epoch. The genus contains two described species, the type species M. anomopodus described in 1953 by Ruben Arthur Stirton and M. federicoi, described and included in the genus by Darin A. Croft.
Caiman brevirostris is an extinct species of caiman that lived during the Late Miocene, around 11.6 million years ago, to the end of the Miocene 5.3 million years ago in Acre and Amazonas, Brazil as well as Urumaco, Venezuela. Several specimens have been referred to the species, but only 3 of them are confidently placed in the species. C. brevirostris was originally named in 1987 on the basis of a single, incomplete rostrum with an associated mandibular ramus that had been found in Acre, Brazil. C. brevirostris is very distinct among Caiman species and caimaninae overall in that it preserves a characteristically short and robust skull that bears blunt posterior teeth that were built to break down harder foods. This was an adaption for durophagy, likely to crush shells of mollusks and clams which were common in the wetlands that C. brevirostris resided in.
Pseudoprepotherium is an extinct genus of sloths of the family Mylodontidae. It was widespread across northern South America during the Early to Late Miocene epoch around 21 to 5.3 million years ago. Fossils of the animal have been found in Brazil, Venezuela, and Peru. Pseudoprepotherium lived in a tropical climate with a water-rich environment. Their known remains are limited to limb bones, except for a few skulls and teeth. Based on these remains, they were most likely medium to large-sized mylodontid. The genus was described in 1961 and currently contains three species, which were originally assigned to the genus Prepotherium.