Globidentosuchus

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Globidentosuchus
Temporal range: Mid-Late Miocene (Mayoan-Montehermosan),
11.6–5.3  Ma [1]
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Crocodilia
Family: Alligatoridae
Subfamily: Caimaninae
Genus:† Globidentosuchus
Scheyer et al., 2013
Type species
†Globidentosuchus brachyrostris
Scheyer et al., 2013

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. [2] 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. [3] [2] It is thought to be one of the most basal Caimanines, even sharing some traits with alligatorids. [2]

Contents

Etymology

The generic name Globidentosuchus is derived from the Latin roots globus meaning "sphere" and dens meaning "tooth", referring to the spherical teeth in the posterior skull, and Greek souchos meaning "crocodile" after its classification. The species name brachyrostris is derived from the Greek brachys meaning "short" and Latin rostrum meaning "snout" after the truncated and robust rostrum of the species. [2]

History and taxonomy

Globidentosuchus was described in 2013 by T. M. Scheyer and colleagues, the type and only species being G. brachyrostris, on the basis of cranial and mandibular remains that had been collected from the El Picache and Domo de Agua Blanca localities in Urumaco, Venezuela, the fossils coming from the Upper Miocene aged strata of the Upper and Middle Members of the Urumaco Formation. [2] The chosen holotype (AMU-CURS-222) consists of a nearly skull with associated mandibles, including several of the spherical crushing teeth, and the paratype (AMU-CURS-224) was more fragmentary, consisting of only an incomplete skull associated with mandibles. Some other fragmentary specimens were referred in 2013 and 2016, but all were either fossils of the skull or mandible. [2] [3] In 2017, a partial skull that was first described as a skull of Melanosuchus fisheri from the Urumaco Formation of Falcón, Venezuela was reassigned to Globidentosuchus, making it the first known Globidentosuchus specimen. [4]

Description and paleobiology

Globidentosuchus was a small caimanine species at only 1.72 metres (5.6 ft) meters in length and 16.7 kilograms (37 lb) in weight, around the same size as the average adult male Caiman crocodilus . [5] The most notable feature of Globidentosuchus is its U-shaped, wide, and short skull and robust, deep mandibles that were built for crushing hard prey like molluscs. [6] [2] Globidentosuchus differentiates from other caimanines in several areas, such as; a fused external naris that was not bisected by the nasals, the smooth skull with weak preorbital ridges and no rostral or interorbital ridges, in strong contrast to the strong ridges in gavialoids and some caimans. [6] [2] Each mandible preserves 18 teeth, 10 conical teeth in the anterior portion and 8 spherical, robust teeth in the posterior portion. These spherical teeth were tightly packed, making a crushing unit that was built to crush molluscs. [2] This morphology is also observed in several other caimanines, like Caiman brevirostris, [7] C. latirostris, and Allognathosuchus , though none of these taxa have crushing units like in Globidentosuchus. [2] The mandible has 13 alvelovi, the largest being in the back of the mandible but they get much smaller after the 4th alvelovi, a trait missing in other caimanines but was likely convergently evolved as some early alligatoroids bare this. [2]

Classification

Globidentosuchus is often recovered as one of or the most basal caimanines, with the original phylogenetic analysis in 2013 finding it to be a stem caimanine and the sister taxon to all other caimanines, even more basal than Paleogene caimanines like Necrosuchus and Eocaiman. [2] Hastings et al. (2013) proposed that this phylogenetic position is because of a potential relict population of basal caimanines that persisted in Central America and/or northern South America into the Late Miocene, as shown by Globidentosuchus and its basal relatives Gnatusuchus and Culebrasuchus, [8] [6] though more fossils are needed to confirm this. [9]

The following tree is based on the results recovered by Cidade et al. (2017), [10] excluding the North American Orthogenysuchus and including the then newly named Mourasuchus pattersoni while also following the synonymy of M. nativus with M. arendsi. This analysis also recovers Globidentosuchus as one of the most basal caimanines at a similar level to Culebrasuchus and Gnatusuchus. [4] [2]

Alligatoridae

Alligatorinae

Caimaninae

Culebrasuchus mesoamericanus

Gnatusuchus pebasensis

Globidentosuchus brachyrostris

Eocaiman palaeocenicus

Eocaiman cavernensis

Eocaiman itaboraiensis

Kuttanacaiman iquitosensis

Tsoabichi greenriverensis

Paleosuchus palpebrosus

Paleosuchus trigonatus

Caiman wannlangstoni

Jacarea

Caiman yacare

Caiman crocodilus

Caiman brevirostris

Caiman latirostris

Melanosuchus niger

Centenariosuchus gilmorei

Purussaurus neivensis

Purussaurus mirandai

Mourasuchus arendsi

Mourasuchus atopus

Mourasuchus amazonensi

Mourasuchus pattersoni

UFAC-1424

Paleoenvironment

As the Proto-Amazonian lake system and the Pebas system began to dissipate with the onset of the transcontinental Amazon Drainage, Globidentosuchus inhabited the wetlands of the northern Urumaco Formation in Venezuela into the Late Miocene before eventually dying out by the Early Pliocene like much of the large crocodilian fauna of the Miocene wetlands. These wetlands provided favorable conditions to the native reptilian fauna, with several lineages of crocodilians reaching enormous sizes during the Mid to Late Miocene and also diversifying in ecology. Some of the enormous crocodilians that coexisted with Globidentosuchus included the enormous caimain Purussaurus , the bizarre Mourasuchus and large-bodied gharials of the genus Gryposuchus , some species of which reaching lengths of over 10 meters. [11] The largest turtle known, Stupendemys, with one specimen preserving a 2.86 meter long carapace, was also present in the region as an omnivore. [12] Other durophagus caimanines inhabited the Urumaco, including the unusual Caiman brevirostris and extant C. latirostris . [3] Besides the aforementioned reptiles, the waterways of Late Miocene South America were also inhabited by fish, including catfish such as Phractocephalus and Callichthyidae, characids such as Acregoliath rancii and the tambaqui (Colossoma macropomum), the South American lungfish (Lepidosiren paradoxa), trahiras (e.g. Paleohoplias assisbrasiliensis ) and freshwater rays and sharks. Other turtles and tortoises found in the same deposits are Chelus columbiana (a fossil relative of the mata mata) and Chelonoidis . Further aquatic vertebrates included river dolphins and the large darter "Anhinga" fraileyi . Palynofloras found in the Urumaco Formation suggest a continuation of the Amazonian forest into northwestern Venezuela during the Miocene, [13] [14] while the Early Pliocene replaced these forests with xerophyte-dominated habitats after the collapse of the Urumaco delta and its environment, [15] which ended the great crocodilian diversity that was present in Venezuela. [16] [15]

Related Research Articles

<span class="mw-page-title-main">Alligatoridae</span> Family of crocodilians including alligators, caimans and kin

The family Alligatoridae of crocodylians includes alligators, caimans and their extinct relatives.

<i>Melanosuchus</i> Genus of caiman

Melanosuchus is a genus of alligatorid caiman. The black caiman of South America is the sole extant (living) species, and is the largest living member of the subfamily caimaninae, and the entire alligator family.

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

Purussaurus is an extinct genus of giant caiman that lived in South America during the Miocene epoch, from the Friasian to the Huayquerian in the SALMA classification. It is known from skull material found in the Brazilian and Peruvian Amazon, Colombian Villavieja Formation, Panamanian Culebra Formation and the Urumaco and Socorro Formations of northern Venezuela.

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

Mourasuchus is an extinct genus of giant, aberrant caiman from the Miocene of South America. Its skull has been described as duck-like, being broad, flat, and very elongate, superficially resembling Stomatosuchus from the Late Cretaceous.

<span class="mw-page-title-main">Caiman</span> Subfamily of reptiles

A caiman is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South America from marshes and swamps to mangrove rivers and lakes. They have scaly skin and live a fairly nocturnal existence. They are relatively small-sized crocodilians with an average maximum weight of 6 to 40 kg depending on species, with the exception of the black caiman, which can grow more than 4 m (13 ft) in length and weigh in excess of 1,000 kg. The black caiman is the largest caiman species in the world and is found in the slow-moving rivers and lakes that surround the Amazon basin. The smallest species is the Cuvier's dwarf caiman, which grows to 1.2 to 1.5 m long. There are six different species of caiman found throughout the watery jungle habitats of Central and Southern America. The average length for most of the other caiman species is about 2 to 2.5 m long.

<span class="mw-page-title-main">Alligatorinae</span> Subfamily of reptiles

Alligatorinae is a subfamily within the family Alligatoridae that contains the alligators and their closest extinct relatives, and is the sister taxon to Caimaninae. Many genera in Alligatorinae are described, but only the genus Alligator is still living, with the remaining genera extinct.

<i>Gryposuchus</i> Extinct genus of gavialoid crocodilian

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.

Hesperogavialis is an extinct genus of gryposuchine gavialid. Fossils have been found from Venezuela and Brazil that date back to the Middle to Late Miocene. Although Hesperogavialis is one of the best known gavialoids from South America, the posterior portion of the skull is still unknown, making any attempts at classification within the family somewhat more difficult than other gavialoids in which much of the skull is present. The genus possibly comprises three species. The type species, H. cruxenti, has been found in the Urumaco Formation in Venezuela. A second possible species, named H. bocquentini, has been described from the Solimões Formation in Acre, Brazil, and can be distinguished from H. cruxenti by the asymmetry seen in the anterior portion of the nasals and the small distance between alveoli. A third species can be recognized from the same locality in Acre, although a formal name has yet to be given to it.

Ikanogavialis is an extinct genus of gavialid crocodilian. Fossils have been found in the Urumaco Formation in Urumaco, Venezuela and the Solimões Formation of Brazil. The strata from which remains are found are late Miocene in age, rather than Pliocene as was once thought. A possible member of this genus survived into the Late Holocene on Muyua or Woodlark Island in Papua New Guinea.

Orthogenysuchus is an extinct genus of caimanine alligatorids. Fossils have been found from the Wasatch Beds of the Willwood Formation of Wyoming, deposited during the early Eocene. The type species is O. olseni. The holotype, known as AMNH 5178, is the only known specimen belonging to the genus and consists of a skull lacking the lower jaws. The braincase is filled in by the matrix and most of the suture lines between bones are indiscernible, making comparisons with other eusuchian material difficult.

Gryposuchinae is an extinct subfamily of gavialid crocodylians. Gryposuchines lived mainly in the Miocene of South America. However, "Ikanogavialis" papuensis may have survived more recently, into the Late Pleistocene/Holocene. Most were long-snouted coastal forms. The group was named in 2007 and includes genera such as Gryposuchus and Aktiogavialis, although a 2018 study indicates that the group might be paraphyletic and rather an evolutionary grade towards the gharial.

Culebrasuchus is an extinct, monotypic genus of caiman alligatorid known from the Early to Middle Miocene (Hemingfordian) of the Panama Canal Zone of Panama. It contains a single species, Culebrasuchus mesoamericanus.

<i>Caiman wannlangstoni</i> Extinct species of reptile

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.

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

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.

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

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.

The Urumaco Formation is a formation in Venezuela that includes deposits from the Late Miocene. It is the site of several "giant forms": the turtles, crocodiles, sloths and rodents of Urumaco are among the largest of their groups.

Bairdemys is an extinct genus of side-necked turtles in the family Podocnemididae. The genus existed from the Late Oligocene to Late Miocene and its fossils have been found in South Carolina, Puerto Rico, Panama and Venezuela. The genus was described in 2002 by Gaffney & Wood and the type species is B. hartsteini.

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.

Acresuchus is an extinct monospecific genus of medium-sized caiman from the Late Miocene of western Brazil andVenezuela. The genus contains a single species, Acresuchus pachytemporalis. Acresuchus is a close relative of the giant caiman Purussaurus.

<i>Magdalenabradys</i> Extinct genus of ground sloths

Magdalenabradys is an extinct genus of mylodontid ground sloths that lived during the Middle Miocene and Early Pliocene of what is now Colombia and Venezuela. Fossils have been found in the Villavieja Formation of the Honda Group in Colombia, and the Codore and Urumaco Formations of Venezuela.

References

  1. ↑ Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ . 9: e12094. doi: 10.7717/peerj.12094 . PMC   8428266 . PMID   34567843.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 Scheyer, T. M.; Aguilera, O. A.; Delfino, M.; Fortier, D. C.; Carlini, A. A.; Sánchez, R.; Carrillo-Briceño, J. D.; Quiroz, L.; Sánchez-Villagra, M. R. (2013). "Crocodylian diversity peak and extinction in the late Cenozoic of the northern Neotropics" (PDF). Nature Communications. 4: 1907. Bibcode:2013NatCo...4.1907S. doi: 10.1038/ncomms2940 . PMID   23695701.
  3. 1 2 3 Scheyer, T. M., & Delfino, M. (2016). The late Miocene caimanine fauna (Crocodylia: alligatoroidea) of the Urumaco Formation, Venezuela. Palaeontologia Electronica, 19(3), 1-57.
  4. 1 2 Bona, Paula; Blanco, M. Victoria Fernandez; Schever, Torsten M.; Both, Christian (2017). "Shedding Light on the Taxonomic Diversity of the South American Miocene Caimans: The Status of Melanosuchus fisheri (Crocodylia, Alligatoroidea)". Ameghiniana. 54 (6): 681–687. doi:10.5710/AMGH.08.06.2017.3103. ISSN   0002-7014. S2CID   55376533.
  5. ↑ Britton, Adam. "Spectacled Caiman (Caiman crocodilus)". Crocodilian Species List. Retrieved 27 March 2019.
  6. 1 2 3 Salas-Gismondi, Rodolfo; Flynn, John J.; Baby, Patrice; Tejada-Lara, Julia V.; Wesselingh, Frank P.; Antoine, Pierre-Olivier (2015-04-07). "A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands". Proceedings of the Royal Society B: Biological Sciences. 282 (1804): 20142490. doi:10.1098/rspb.2014.2490. PMC   4375856 . PMID   25716785.
  7. ↑ Fortier, Daniel C.; De Souza-Filho, Jonas P.; Guilherme, Edson; Maciente, Andréa A. R.; Schultz, Cesar L. (2014-06-07). "A new specimen of Caiman brevirostris (Crocodylia, Alligatoridae) from the late Miocene of Brazil". Journal of Vertebrate Paleontology. 34 (4): 820–834. doi:10.1080/02724634.2014.838173. ISSN   0272-4634. S2CID   86506092.
  8. ↑ Hastings, Alexander K.; Bloch, Jonathan I.; Jaramillo, Carlos A.; Rincon, Aldo F.; Macfadden, Bruce J. (2013-03-01). "Systematics and biogeography of crocodylians from the Miocene of Panama". Journal of Vertebrate Paleontology. 33 (2): 239–263. doi: 10.1080/02724634.2012.713814 . ISSN   0272-4634.
  9. ↑ Hastings, Alexander K.; Reisser, Moritz; Scheyer, Torsten M. (2016). "Character evolution and the origin of Caimaninae (Crocodylia) in the New World Tropics: new evidence from the Miocene of Panama and Venezuela". Journal of Paleontology. 90 (2): 317–332. doi:10.1017/jpa.2016.37. ISSN   0022-3360. S2CID   88661043.
  10. ↑ Cidade, Giovanne M.; Solórzano, Andrés; Rincón, Ascanio Daniel; Riff, Douglas; Hsiou, Annie Schmaltz (2017-03-07). "A new Mourasuchus (Alligatoroidea, Caimaninae) from the late Miocene of Venezuela, the phylogeny of Caimaninae and considerations on the feeding habits of Mourasuchus". PeerJ. 5: e3056. doi: 10.7717/peerj.3056 . ISSN   2167-8359. PMC   5344020 . PMID   28286712.
  11. ↑ Head, J. J. (2001). "Systematics and body size of the gigantic, enigmatic crocodyloid Rhamphosuchus crassidens, and the faunal history of Siwalik Group (Miocene) crocodylians". Journal of Vertebrate Paleontology. 21 (Supplement to No. 3): 59A.
  12. ↑ Cadena, E.-A.; Scheyer, T. M.; Carrillo-Briceño, J. D.; Sánchez, R.; Aguilera-Socorro, O. A; Vanegas, A.; Pardo, M.; Hansen, D. M.; Sánchez-Villagra, M. R. (2020-02-14). "The anatomy, paleobiology, and evolutionary relationships of the largest extinct side-necked turtle". Science Advances. 6 (7): eaay4593. doi:10.1126/sciadv.aay4593. ISSN   2375-2548. PMC   7015691 . PMID   32095528.
  13. ↑ Jaramillo, C., Hoorn, C., Silva, S. A., Leite, F., Herrera, F., Quiroz, L., ... & Antonioli, L. (2010). The origin of the modern Amazon rainforest: implications of the palynological and palaeobotanical record. Amazonia, landscape and species evolution, 317, 334.
  14. ↑ Sánchez-Villagra, M. R., Aguilera, O. A., & Carlini, A. A. (2010). Urumaco and Venezuelan Paleontology: the fossil record of the Northern Neotropics. Indiana University Press.
  15. 1 2 Hoorn, C., Wesselingh, F. P., Ter Steege, H., Bermudez, M. A., Mora, A., Sevink, J., ... & Antonelli, A. (2010). Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity. science, 330(6006), 927-931.
  16. ↑ Díaz de Gamero, María L. (1996-07-01). "The changing course of the Orinoco River during the Neogene: a review". Palaeogeography, Palaeoclimatology, Palaeoecology. 123 (1): 385–402. doi:10.1016/0031-0182(96)00115-0. ISSN   0031-0182.
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