Sigilmassasaurus brevicollis

Overview

Sigilmassasaurus, meaning "Sijilmassa lizard" (named after an ancient Moroccan city), was a large spinosaurid dinosaur that lived approximately 100-94 million years ago during the Late Cretaceous in what is now Morocco. This mysterious predator is one of the most debated dinosaurs—some scientists think it might actually be the same animal as the famous Spinosaurus!

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Taxonomy & Classification

• Clade: Theropoda
• Family: Spinosauridae
• Diet: Carnivorous
• Locomotion: Bipedal

Sigilmassasaurus was closely related to (or possibly identical to) Spinosaurus aegyptiacus.

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Physical Characteristics

Size & Build

• Length: 12.8-16 meters (42-52 feet)—possibly very large!
• Height: Possibly 4+ meters (13+ feet) at the hip
• Weight: About 8,000 kg (8.8 tons)
• Build: Large spinosaurid body plan

The Distinctive Vertebrae

Sigilmassasaurus is known mainly from its neck bones:

• Short, wide neck vertebrae—very unusual!
• Species name "brevicollis" means "short neck"
• The vertebrae are wider than they are long
• This feature sets it apart from other spinosaurids
• Or does it? Scientists still debate!

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The Great Spinosaurus Debate

Same Animal or Different?

Scientists can't agree on Sigilmassasaurus:

Team "Same Species":

• The vertebrae could just be Spinosaurus neck bones
• Found in the same rocks as Spinosaurus
• Similar time and place
• May represent individual variation in Spinosaurus

Team "Separate Species":

• The vertebrae are distinctly different
• The short, wide shape is unique
• Morocco had multiple large predators
• Deserves its own name

The debate continues!

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Life in the Kem Kem Beds

An Incredible Ecosystem

Sigilmassasaurus lived in a predator-packed world:

• The Kem Kem Group of Morocco
• One of the most dinosaur-rich formations ever
• Multiple giant predators coexisting
• Ancient river systems with abundant fish

Ecosystem Neighbors

Shared its world with:

• Spinosaurus (or was the same animal?)
• Carcharodontosaurus—another giant theropod
• Deltadromeus—a fast-running predator
• Onchopristis—giant sawfish (prey)
• Pterosaurs and crocodilians

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A Fish-Eater?

Spinosaurid Diet

If Sigilmassasaurus was a spinosaurid:

• Probably ate fish as main diet
• Crocodile-like snout (based on related species)
• Conical teeth for gripping slippery prey
• May have also eaten other dinosaurs
• Semi-aquatic lifestyle likely

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Discovery & History

A Complicated Story

• First described in 1996 by Dale Russell
• Based on vertebrae from Morocco
• Named after Sijilmassa, a medieval Moroccan trading city
• Fossils came from the Kem Kem Beds
• Classification has been debated ever since!

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Why So Confusing?

The Fossil Problem

Sigilmassasaurus is hard to understand because:

• Known mainly from isolated bones
• No complete skeleton found
• The Kem Kem fossils are often mixed together
• Hard to tell which bones go with which animal
• Multiple species lived in the same environment

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Scientific Importance

Part of a Bigger Picture

Even if it's just Spinosaurus:

• Shows variation in spinosaurid anatomy
• Helps us understand Kem Kem biodiversity
• Part of understanding how many predators coexisted
• The debate pushes scientific research forward

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Cool Facts

• Sigilmassasaurus might be Spinosaurus in disguise—or a completely different animal!
• Its name comes from Sijilmassa, an ancient trade city in Morocco
• The species name means "short neck"—referring to its unusual vertebrae
• Found in one of the most predator-packed ecosystems ever
• Scientists have been debating its identity for nearly 30 years!
• If separate from Spinosaurus, it's one of the largest spinosaurids
• The Kem Kem Beds have produced some of the most mysterious dinosaur fossils

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Sigilmassasaurus is paleontology's mystery dinosaur—is it Spinosaurus's secret identity or a giant of its own? Only more fossils will tell!