3. Which index fossil may be found in the surface bedrock near Ithaca, New York?

A)

B)

C)

D)

Correct Answer: Option D – Bothriolepis

Bothropelpis was a small benthic freshwater detrivore, around 30 centimetres long, which lived in the Middle and Late Devonian (387–360 million years ago) period. Because the fossils are found in freshwater sediments, Bothriolepis is presumed to have spent most of its life in freshwater rivers and lakes, but was probably able to enter salt water as well because its range appeared to have corresponded with the Devonian continental coastlines.

Bothriolepis fossils generally consist of the robust plates that surround its head and thorax, as well as the unusual streamlined fins attached to the back of its skull. This heavily boned front part of the animal is typically all that is preserved.

Fossils are abundant in the Ithaca area. All date from the Ordovician to the Late Devonian Period, and all were buried in mud and sand that accumulated in a shallow sea between 450 and 360 million years ago. Life in this warm ancient sea was abundant and diverse, just as in warm seas today.

Since, the climatic conditions of Ithaca around the Devonian period supported water borne life forms, Bothriolepis lived there, providing evidence through their fossil remains found in this region today.

Incorrect Options

Coelophysis is a land borne creature and one of the earliest known Dinosaurs which lived in the Triassic period extending between 255 and 199 million years ago into the Mesozoic era.

Elliptocephala is a fossil of marine arthropods, the trilobites which lived during the later part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago.

Maclurites is the fossil of land borne, Ordovician gastropods which lived in the period extending between 505 and 438 million years ago.

Hence, options A, B and C are incorrect.