13-million-year-old ‘storyteller’ crocodylian fossils show evidence for parallel evolution

Related Articles

Related Articles

The 13-million-year-old fossils of an extinct crocodylian, named ‘the storyteller,’ suggest that South American and Indian species evolved separately to acquire protruding, ‘telescoped’ eyes for river-dwelling, according by Rodolfo Salas-Gismondi from the University de Montpellier, France, and colleagues.

The gavialoids are a diversified group of mostly extinct long-snouted crocodylian species. Many of the evolutionary relationships between these species remain unclear; fossils of extinct gavialoids from South America and the extant Indian gharial gavialoid have similar telescoped eyes, but it was not known how these features evolved.

The authors of the present study examined Peruvian fossils from a 13-million-year-old South American species, the oldest known gavialoid crocodylian from the Amazon, which they named Gryposuchus pachakamue after Pachakamue, a pre-Hispanic South American ‘storyteller’ god thought to have knowledge about the origins of South American life. The fossils were dated as Middle Miocene and came from the Pebas Formation, which was likely made up of swampy waterways, suggesting that the crocodylian had a river-dwelling lifestyle. It had only slightly telescoped eyes. The researchers conducted phylogenetic and morphometric analysis to assess the likely evolutionary development of the protruding telescoped eyes of Indian and South American species.

 

Time calibrated phylogenetic tree of the Gavialoidea and relevant paleogeographic distributions associated with the evolution and diversification of gavialoids in marine and freshwater settings. During the Late Paleocene-Early Eocene interval, peaks of sea surface temperature (SST) and global sea surface level (GSL) occurred together with tropical marine connections through the Tethys Ocean and Caribbean Sea [59,60]. During the Neogene, distinct biomes dominated tropical South America: (A) Acre Phase, after the onset of the eastern-draining Amazon and northward-draining Orinoco river systems; and (B) Pebas Mega-Wetland System, with its drainage northward to the Caribbean Sea. Abbreviations: Olig., Oligocene; Ple., Pleistocene; Pli., Pliocene. Global and South American schematic paleogeography adapted from Blakey [60] and Hoorn et al. [61], respectively. CREDIT Salas-Gismondi et al.
Time calibrated phylogenetic tree of the Gavialoidea and relevant paleogeographic distributions associated with the evolution and diversification of gavialoids in marine and freshwater settings. During the Late Paleocene-Early Eocene interval, peaks of sea surface temperature (SST) and global sea surface level (GSL) occurred together with tropical marine connections through the Tethys Ocean and Caribbean Sea [59,60]. During the Neogene, distinct biomes dominated tropical South America: (A) Acre Phase, after the onset of the eastern-draining Amazon and northward-draining Orinoco river systems; and (B) Pebas Mega-Wetland System, with its drainage northward to the Caribbean Sea. Abbreviations: Olig., Oligocene; Ple., Pleistocene; Pli., Pliocene. Global and South American schematic paleogeography adapted from Blakey [60] and Hoorn et al. [61], respectively.
CREDIT : Salas-Gismondi et al.
Their analysis suggested that the ‘storyteller’ crocodylian with slightly telescoped eyes represents the ancestral condition from which the South American lineage evolved telescoped eyes. The eyes therefore evolved in parallel in South American and Indian lineages, at first showing partial telescoping as in the ‘storyteller’ crocodylian, and eventually becoming fully telescoped as seen in later-evolving species. Both South American and Indian species adopted a river-dwelling lifestyle, and it is likely that telescoped eyes were adaptive, helping them to catch fish in these habitats.

Although further research is needed, thibs study may further our understanding of both the ‘storyteller’ crocodylian and the evolution of all gavialoid crocodylians.

Access to the freely available paper: http://dx.plos.org/10.1371/journal.pone.0152453

PLOS

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

Giant Sand Worm Discovery Proves Truth is Stranger Than Fiction

Simon Fraser University researchers have found evidence that large ambush-predatory worms--some as long as two metres--roamed the ocean floor near Taiwan over 20 million years ago.

Burial Practices Point to an Interconnected Early Medieval Europe

Early Medieval Europe is frequently viewed as a time of cultural stagnation, often given the misnomer of the 'Dark Ages'. However, analysis has revealed new ideas could spread rapidly as communities were interconnected, creating a surprisingly unified culture in Europe.

New Starfish-Like Fossil Reveals Evolution in Action

Researchers from the University of Cambridge have discovered a fossil of the earliest starfish-like animal, which helps us understand the origins of the nimble-armed creature.

Mars Crater Offers Window on Temperatures 3.5 Billion Years Ago

Once upon a time, seasons in Gale Crater probably felt something like those in Iceland. But nobody was there to bundle up more than 3 billion years ago.

Early Humans Used Chopping Tools to Break Animal Bones & Consume the Bone Marrow

Researchers from the Sonia and Marco Nadler Institute of Archaeology at Tel Aviv University unraveled the function of flint tools known as 'chopping tools', found at the prehistoric site of Revadim, east of Ashdod.

50 Million-Year-Old Fossil Assassin Bug Has Unusually Well-Preserved Genitalia

The fossilized insect is tiny and its genital capsule, called a pygophore, is roughly the length of a grain of rice.

Dinosaur-Era Sea Lizard Had Teeth Like a Shark

New study identifies a bizarre new species suggesting that giant marine lizards thrived before the asteroid wiped them out 66 million years ago.

The Iron Age Tribes of Britain

The British Iron Age is a conventional name to describe the independent Iron Age cultures that inhabited the mainland and smaller islands of present-day Britain.

Popular stories

The Iron Age Tribes of Britain

The British Iron Age is a conventional name to describe the independent Iron Age cultures that inhabited the mainland and smaller islands of present-day Britain.

The Roman Conquest of Wales

The conquest of Wales began in either AD 47 or 48, following the landing of Roman forces in Britannia sent by Emperor Claudius in AD 43.

Vallum Antonini – The Antonine Wall

The Antonine Wall (Vallum Antonini) was a defensive wall built by the Romans in present-day Scotland, that ran for 39 miles between the Firth of Forth, and the Firth of Clyde (west of Edinburgh along the central belt).

Vallum Aulium – Hadrian’s Wall

Hadrian’s Wall (Vallum Aulium) was a defensive fortification in Roman Britannia that ran 73 miles (116km) from Mais at the Solway Firth on the Irish Sea to the banks of the River Tyne at Segedunum at Wallsend in the North Sea.