Dyrosaurus phosphaticus

Overview

A long, slender snout occupying most of the head first catches the eye. Dyrosaurus phosphaticus is a crocodile relative known from early Eocene North Africa. Comparing it with river crocodiles today introduces crocodyliforms of ancient seas.^[1][4]

Key facts

The snout has been described as occupying approximately 68% of skull length. More than two-thirds of the head thus extended forward. Notice how different the prey-grasping front region is from the rear region housing the eyes and brain.^[1]

Time and place

Its fossils date to the Ypresian of the early Eocene, within a range of approximately 56–48 million years ago. It is known from Tébessa in present-day Algeria and Djebel Thelja near Métlaoui in Tunisia. North African phosphate beds are an important setting for studying this crocodile relative.^[1][3]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

Both upper and lower jaws are long and narrow. The orientation of the nostrils and eye sockets, nasal bones, and structures at the back of the head have been studied in detail. Compare the snout’s length with the width of the head behind the eyes.^[1][2]

Dyrosaurus phosphaticus is estimated to have had a total body length of approximately 7.8 m. This literature value was compiled in a 2024 comparative study of marine life and represents the entire body, including the long snout.^[11]

Habitat and reproduction

Dyrosaurids include crocodyliforms that lived in seas and coastal environments. Comparing this species’ long, slender jaws with those of its relatives raises questions about grasping prey underwater. Ancient crocodile relatives occupied settings far beyond the riverbanks familiar today.^[4][1]

Fossil discovery

Named in 1893, this species has been studied repeatedly. In 2005, Jouve prepared specimens more precisely and newly described the braincase and passages for nerves. Even a familiar fossil can reveal new information when more bone is exposed from the rock.^[1]

References

1. Jouve, S. (2005). A new description of the skull of Dyrosaurus phosphaticus (Thomas,1893) (Mesoeucrocodylia: Dyrosauridae) from the Lower Eocene of North Africa. Canadian Journal of Earth Sciences 42(3):323–337. DOI10.1139/E05-008.
2. Jouve (2005) — A new description of the skull of Dyrosaurus phosphaticus
3. ICS geologic time chart2024/12
4. 2008 — New dyrosaurid crocodylomorph and faunal turnover at the K–P transition
5. Jouve, S. (2005). A new description of the skull of Dyrosaurus phosphaticus (Thomas,1893) (Mesoeucrocodylia: Dyrosauridae) from the Lower Eocene of North Africa. Canadian Journal of Earth Sciences 42(3):323–337. DOI10.1139/E05-008.
6. 2008 — New dyrosaurid crocodylomorph and faunal turnover at the K–P transition
7. ICS geologic time chart2024/12
8. Jouve (2005) — A new description of the skull of Dyrosaurus phosphaticus
9. Gheerbrant et al.2005 — The skull and teeth of the early proboscidean Phosphatherium
10. Gheerbrant et al.2005 — New material of Phosphatherium and proboscidean evolution
11. Pimiento et al. (2024) — Extinct large marine organisms of the Phanerozoic

Research questions

How can crocodile relatives with similarly long snouts be distinguished? Adding features of the whole skull to studies once based on jaws enabled more detailed comparisons of relationships. Keys to classification also lie behind the very long face.^[1]

Observation

Follow the long outline from the snout to the eye sockets.^[1]