New Extinct Gharial-Related Crocodilian Discovered in Egypt

Why in News?

Scientists have identified a new species of extinct crocodilian, Herugavialis cairensis, from Egypt. The species lived approximately 45 million years ago during the Eocene Epoch and belonged to the gavial lineage, making it an ancient relative of the modern gharial (Gavialis gangeticus) of the Indian subcontinent.

Key Findings

 Identification of a New Species

• The fossil material of Herugavialis cairensis includes a relatively well-preserved skull recovered from the Mokattam Formation of Egypt.
• Although the specimen was discovered during the 1920s, it had earlier been assigned to another crocodilian group, particularly the Tomistoma lineage.
• Researchers have now re-examined the specimen using modern imaging and CT-scanning techniques. The internal and external anatomical features of the skull revealed characteristics that distinguish it from previously known species.
• This led to its recognition as a distinct extinct species.

Geological and Evolutionary Context

• The species lived during the Eocene Epoch, which extended from approximately 56 to 33.9 million years ago.

The Eocene was characterized by:

• relatively warm global climatic conditions;
• significant diversification of mammals;
• major evolutionary changes in terrestrial and aquatic ecosystems; and
• widespread distribution of several ancient reptilian groups.

Therefore, the fossil provides evidence for the diversity of crocodilians during the Eocene.

Connection with the Modern Gharial

• The newly identified species belonged to the gavial group, which includes crocodilians characterized by an elongated and relatively narrow snout.

The modern Indian gharial is:

• Scientific name: Gavialis gangeticus
• Family: Gavialidae
• Habitat: Freshwater rivers
• Distribution: Indian subcontinent
• Feeding adaptation: Primarily piscivorous
• Distinctive feature: Extremely long and narrow snout
• IUCN status: Critically Endangered

The discovery of an ancient gavial relative in Egypt demonstrates that the evolutionary history of this lineage was geographically much broader than its present-day distribution.

Mokattam Formation

• The fossil was recovered from the Mokattam Formation in Egypt.
• The Mokattam Formation is important from both geological and archaeological perspectives because the Mokattam limestone is associated with the geology of the Giza region.
• The region is famous for major ancient Egyptian monuments, including the Great Sphinx and the Giza pyramids.

Significance for Biogeography

• The discovery has implications for palaeobiogeography, which studies the geographical distribution of organisms in the geological past.

The presence of a gavial-related crocodilian in Eocene Egypt suggests that:

1. gavial-like crocodilians once had a broader geographical distribution;
2. their evolutionary history cannot be understood only from the modern Indian gharial;
3. environmental conditions in the Eocene supported a greater diversity of crocodilian groups; and
4. subsequent climatic, sea-level and ecological changes influenced their distribution and extinction.

Crocodilians that once inhabited regions around the Mediterranean eventually disappeared from the area.

Why is the Discovery Important for India?

• The discovery is relevant to India because the modern gharial is one of the most distinctive and threatened reptiles of the Indian subcontinent.
• The gharial is strongly associated with large river systems and has morphological adaptations for catching fish.

Its conservation is closely linked to:

• availability of suitable riverine habitat;
• maintenance of river flow;
• availability of fish;
• protection of nesting and basking sites; and
• reduction of human-induced disturbances.

The fossil discovery provides an evolutionary perspective to the conservation of the surviving gharial lineage.

MCQ ENGLISH

Q. With reference to the recently identified Herugavialis cairensis, consider the following statements:

1. It is an extinct crocodilian species belonging to the ancient gavial lineage.
2. Its fossil was recovered from the Mokattam Formation in Egypt.
3. It lived during the Eocene Epoch.
4. Its discovery suggests that ancient gavial-like crocodilians had a wider geographical distribution than the modern gharial.
5. The modern gharial is primarily a marine crocodilian.

Which of the statements given above are correct?

A. 1, 2, 3 and 4 only
B. 1, 2 and 5 only
C. 2, 3, 4 and 5 only
D. 1, 2, 3, 4 and 5

Answer: A. 

Explanation: Herugavialis cairensis is an extinct gavial-related crocodilian from the Eocene of Egypt. Its fossil was recovered from the Mokattam Formation. The discovery provides evidence of a wider ancient geographical distribution of gavial-like crocodilians. The modern gharial (Gavialis gangeticus) is primarily associated with freshwater river ecosystems, not marine habitats.