crocodyliform

2

Genus: Kaprosuchus

…an extinct genus of mahajangasuchid corcodyliform that lived during the Upper Cretaceous period. Kaprosuchus was largely thought to be a terrestrial predator due to the positioning of its orbits, which are positioned dorsally, and its enlarged caniniform teeth are sharp-edged and straight. Kaprosuchus likely was an ambush hunter and hunted like a big cat, using its large tusks to take down relatively large dinosaurs.

Phylogeny

Animalia-Chordata-Reptilia-Crocodylomorpha-Mahajangasuchidae-Kaprosuchus

Images: Jeslin and Carol Abraczinskas

Cold snap: Climate cooling and sea-level changes caused crocodilian retreat

via: Imperial College London

Fluctuating sea levels and global cooling caused a significant decline in the number of crocodylian species over millions of years, according to new research.

Crocodylians include present-day species of crocodiles, alligators, caimans and gavials and their extinct ancestors. Crocodylians first appeared in the Late Cretaceous period, approximately 85 million years ago, and the 250 million year fossil record of their extinct relatives reveals a diverse evolutionary history.

Extinct crocodylians and their relatives came in all shapes and sizes, including giant land-based creatures such as Sarcosuchus, which reached around 12 metres in length and weighed up to eight metric tonnes. Crocodylians also roamed the ocean - for example, thalattosuchians were equipped with flippers and shark-like tails to make them more agile in the sea.

Many crocodylians survived the mass extinction that wiped out almost all of the dinosaurs 66 million years ago, but only 23 species survive today, six of which are classified by the International Union for Conservation of Nature as critically endangered and a further four classified as either endangered or vulnerable…

(Read more: PhysOrg)

illustration by Robert Nichols/Imperial College London

Stratiotosuchus maxhechti attacking a juvenile titanosaur. Art by Maurílio Oliveira (Museu Nacional, Rio de Janeiro).

Baurusuchid crocodyliforms as theropod mimics: clues from the skull and appendicular morphology of Stratiotosuchus maxhechti (Upper Cretaceous of Brazil)

DOUGLAS RIFF, ALEXANDER WILHELM ARMIN KELLNER

Zoological Journal of the Linnean Society Volume 163, Issue Supplement s1, pages S37–S56, December 2011

This odd evolutionary offshoot is Kaprosuchus, whose name literally means “Boar Crocodile”. How rad is that? It’s odd in several ways but most importantly is it’s teeth. They’re very canine in nature and project both above and below the skull. It’s so odd, it doesn’t show up in any other crocodyliform. Another odd trait are the small horns that appear out of the skull. While this feature isn’t unique, it’s an oddity nonetheless. It lived in the Cretaceous period, in present day Niger. It grew up to 20 feet (estimated length, as a complete specimen has yet to be recovered). Finally what sets it apart from other crocodyliforms is that it appears to be almost entirely built for hunting on land, as opposed to water. It’s eye sockets are placed forward like a modern wolf or boar unlike crocodiles whose eyes face outward so as to see everything while underwater. It’s teeth are angled to rip and slash, as opposed to hooking onto prey and dragging them underwater. It primarily feasted on smaller dinosaurs and mammals that it could successfully kill without much risk to itself. (Art is not mine.) #kaprosuchus #crocodyliform #notadinosaur #carnivore #niger #africananimal #paleoartist #paleontology #rad #terrestrial #dinophile

The evolution of the meatal chamber in crocodyliforms

Abstract

The unique outer ear of crocodylians consists of a large meatal chamber (MC) concealed by a pair of muscular earlids that shape a large part of the animal’s head. This chamber is limited medially by the enlarged tympanic membrane. Yet, the anatomy of this distinctive and complex region is underexplored and its evolutionary history untraced. The osteology and soft tissues of the MC in extant crocodylians was analysed to describe it and establish osteological correlates within this region. A broad survey of the osteological correlates was conducted in major clades of fossil crocodyliforms to estimate evolutionary trends of the MC. The reorganization of the MC at the origin of crocodyliforms includes characters also present in more basal taxa such as ‘sphenosuchians’ as well as unique traits of crocodyliforms. Three major patterns are recognized in the MC of basal mesoeucrocodylians. The distinct ‘thalattosuchian pattern’ indicates that extensive modifications occurred in this clade of aquatic fossil crocodyliforms, even when multiple alternative phylogenetic positions are taken into account. Some traits already established in putative closely related clades are absent or modified in this group. The ‘basal notosuchian/sebecian pattern’ is widespread among basal metasuchians, and establishes for the first time characters maintained later in neosuchians and extant forms. The ‘advanced notosuchian pattern’ includes modifications of the MC possibly related to a terrestrial lifestyle and potentially a structure analogous to the mammalian pinna. The main variation in the MC of neosuchians is associated with the homoplastic secondary opening of the cranioquadrate passage. The inferred phylogenetic trends in the crocodyliform MC suggest the great anatomical disparity in this region followed a complex evolutionary pattern, and tympanic hearing played an important role in the origin and diversification of Crocodyliformes.

from Anatomy via Alexandros G.Sfakianakis on Inoreader http://ift.tt/20Ibo1X
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from on Inoreader http://ift.tt/1K0apWR
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