Question

Which of the following fossils was/were completely extinct by the end of Permian?

• A. Favosites
• B. Phacops
• C. Aulacopleura
• D. Lingula

Hint:

Tabulate corals and all trilobites vanished at the end-Permian extinction; one of the four options is a living fossil still around today.

Answer 1

The Correct Option is A, B, C

Step 1: Understanding the Question.
The question asks which of the four fossil taxa listed had died out completely by the close of the Permian period, that is, none of their descendants survived into the Mesozoic era.

Step 2: Key Concept.
The end-Permian mass extinction, about 252 million years ago, was the largest extinction event in Earth's history and wiped out entire groups of marine invertebrates, including all tabulate and rugose corals and the entire class Trilobita. Some groups, however, are true survivors, or living fossils, that continued past the Permian and still exist today.

Step 3: Detailed Explanation.

(A) Favosites: This is a colonial tabulate coral, and the entire subclass Tabulata was wiped out at the end-Permian extinction along with the rugose corals. Favosites did not survive into the Triassic, so it is completely extinct by the end of Permian.

(B) Phacops: This is a trilobite genus, and the whole class Trilobita, already declining through the Palaeozoic, was completely eliminated by the end of the Permian, with no trilobites known from any younger rocks. So Phacops is extinct by the end of Permian.

(C) Aulacopleura: This is also a trilobite genus, and for the same reason as Phacops, it belongs to a class with no record beyond the Permian, so it too is completely extinct by the end of Permian.

(D) Lingula: This is an inarticulate brachiopod genus that is famous as a living fossil, with a fossil record stretching from the early Palaeozoic right through to the present day, since Lingula and its close relatives still live in shallow marine burrows today. It did not go extinct at all, let alone by the end of the Permian.

Step 4: Final Answer.
Favosites, Phacops, and Aulacopleura all belong to groups, tabulate corals and trilobites, that were completely wiped out at the end-Permian extinction, while Lingula survives to the present day.
\[ \boxed{\text{Favosites, Phacops, and Aulacopleura}} \]