''Crocodylus falconensis'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...

known from the early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58San Gregorio Formation of

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

. ''C. falconensis'' was named in

2013 File:2013 Events Collage V2.png, From left, clockwise: Edward Snowden becomes internationally famous for leaking classified NSA wiretapping information; Typhoon Haiyan kills over 6,000 in the Philippines and Southeast Asia; The Dhaka garment fact ...

after

Falcón State ) , anthem = , image_map = Falcon in Venezuela.svg , map_alt = , map_caption = Location within Venezuela , pushpin_map = , pushpin_map_alt = , pushpin_mapsiz ...

and is thought to be the basalmost species of '' Crocodylus'' found in the

Neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropics, tropical Ecoregion#Terrestrial, terrestrial ecoregions of the Americas and the entire South American temperat ...

Description

''C. falconensis'' was a medium-sized species of crocodile with a robust, generalist skull shape. The orbits and the supratemporal fenestrae are notably smaller than those of other ''Crocodylus'' species of the same age, while the nares are comparably larger (however still small relative to the overall skull size). The premaxilla surrounds the nares entirely, excluding the nasal bones from contacting them. Another feature differentiation ''Crocodylus falconensis'' from other species of the genus is that the

supraoccipital The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cereb ...

reaches or at least almost reaches the

foramen magnum The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblon ...

. The roughly triangular skull had a prominent notch located behind the nares to receive one of the enlarged dentary teeth and the center of the rostrum housed a prominent bony boss. Such a boss can also be found in the extant species of the Neotropics, including the

American Crocodile The American crocodile (''Crocodylus acutus'') is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas, with populations present from South Florida and the coasts ...

. Size estimates put ''C. falconensis'' at 4.12 meters long with a weight of 307 kg.

Evolution

Initial phylogenetic analysis by Scheyer and colleagues recovered ''C. falconensis'' as the basal-most of New World ''Crocodylus'' species and sister taxa to all subsequent species of the Americas. This has been interpreted to mean that ''C. falconensis'' was one of, if not the first member of the genus to cross the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

, with all other neotropic ''Crocodylus'' species radiating from South America. A study published in mid 2020, which focused on the phylogenetic placement of the African ''

Crocodylus checchiai ''Crocodylus checchiai'' is an extinct species of crocodile from the Miocene to Pliocene of Libya and Kenya. ''C. checchiai'' was named in 1947 based on a skull from the Sahabi Formation. Remains from the lower Nawata Formation in the Turkana Bas ...

'' recovered slightly different results. In their analysis, neotropic ''Crocodylus'' species retained their monophyletic status and were still recovered as originating from African species that must have crossed the Atlantic, recovering ''C. checchiai'' as the likely Old-World precursor to the American lineage due to their similar morphology, including the prominent dorsal boss. However, their results differ from Scheyer's initial analysis in that despite being the oldest, ''C. falconensis'' was not recovered as the basalmost neotropic species (this role was filled by the

Orinoco Crocodile The Orinoco crocodile (''Crocodylus intermedius'') is a critically endangered crocodile. Its population is very small, and they can only be found in the Orinoco river basin in Colombia and Venezuela. Extensively hunted for their skins in the 19 ...

in Delfino ''et al.'' 2020). In 2021, Hekkala ''et al.'' were able to use

paleogenomics Paleogenomics is a field of science based on the reconstruction and analysis of genomic information in extinct species. Improved methods for the extraction of ancient DNA (aDNA) from museum artifacts, ice cores, archeological or paleontological site ...

, extracting DNA from the extinct ''

Voay ''Voay'' is an extinct genus of crocodile from Madagascar that lived during the Late Pleistocene to Holocene, containing only one species, ''V. robustus''. Numerous subfossils have been found, including complete skulls, noted for their distinctiv ...

'', to better establish the relationships within Crocodylidae, including the subfamilies Crocodylinae and Osteolaeminae. Their results too recover a close connection between the Miocene ''C. checciai'' of Africa and the Pliocene ''C. falconensis'', placing them as sister taxa. However, these results render the origin of neotropic ''Crocodylus'' relatively obscure, as the two species group together at the base of the African-American clade, less derived than either of the two extant African species. Following these results rather than those of Scheyer or Delfino would imply two distinct dispersal events into the Americas. Paleofauna of the San Gregorio Formation

Paleofauna of the San Gregorio Formation

Paleoenvironment

''C. falconensis'' was found in the Vergel Member of the

San Gregorio Formation, Venezuela The San Gregorio Formation is a lithostratigraphic unit dating back to the Pliocene to Pleistocene of Venezuela. The formation is split into three members, the older Vergel Member (Late Pliocene to earliest Pleistocene), the Cocuiza Member (Pleist ...

, which is known for its rich catfish fauna. The abundance of fossil fish has been interpreted to mean that during the Pliocene, this region was largely covered by floodplains and braided rivers, likely accompanied by some woodland and various other bodies of water such as ponds, swamps, flooded areas and even estuaries as indicated by more salt-tolerant animals. ''Crocodylus falconensis'' would have likely inhabited both fresh and brackish water. Other animals found in the region included various

notoungulates Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resem ...

xenarthra Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Ex ...

ns like glypotodonts and

ground sloths Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. The term is used to refer to all extinct sloths because of the large size of the earliest forms discovered, compared to existing tree sloths. The Carib ...

as well as large rodents related to the modern Capybara.

References

{{Taxonbar, from=Q13365851 Crocodylidae Pliocene crocodylomorphs Pliocene reptiles of South America Chapadmalalan Montehermosan Neogene Venezuela Fossils of Venezuela Fossil taxa described in 2013