What We Can Learn From Oysters

Exogyra ponderosa Oyster Fossil (Cretaceous Period 65 to 100 million-years-ago)

A lesson we can learn from oysters is that even though they have no heart to feel and no brain to reason, many of their species build massive reef communities which provide protection for one another; and not only for their own kind, but for many other ocean organisms. Very fittingly, they’ve been referred to as the “unshellfish”.

Exogyra is a large extinct oyster species that lived in the soft sediment of ancient shallow marine waters. It possessed a thick shell with a distinct pattern of ribbing and pitting representing growth lines. Many of its kind thrived during the Upper Cretaceous Period around 65 to 100 million years ago. Their shells opened using a strong abductor muscle to expose a foot which pushed it along and a siphon to filter food and take in oxygen from the ocean water. The abductor muscle scars on the valves are observable in the photo below.

Oyster Exogyra Insides
Exogrya ponderosa Oyster Fossil Upper and Lower Valves

Oysters and Love

In Greek mythology, the Greek Goddess of Love “Aphrodite” was said to have sprang up out of the ocean on an oyster shell. The term “Aphrodisiac”, meaning to heighten love, has been related to oysters ever since.  Also, the charismatic Casanova was known to have eaten twelve oysters a day, believing it would  enrich his love life.

Oyster Exogyra Under
Exogyra ponderosa Oyster Fossil Underside with Upper and Lower Valves in Closed Position


Scientific Name: Exogyra, ponderosa

Common Name: Oyster

Phylum: Mollusk (Large group of marine and fresh water invertebrates having soft bodies enclosed in a shell.)

Class: Pelecypod or Bivalve (Means hinged shell)

Order: Ostreoida (Means true oyster with irregular shell and adductor muscle; pearl oysters are not true oysters.)

Family: Gryphaeidae (Includes honeycomb oyster or foam oyster characterized under magnification with distinct shell structure.)

Genus: Exogyra (Extinct group of large, shallow-marine oysters possessing thick shells with distinctive spiraled peaks and ribbing on upper valves; lower valves were smaller and flattened.)

Species: Ponderosa

The Exogyra in my collection is a beautiful specimen that is quite heavy from being fossilized into solid stone. In the two photos above of its underside, you can clearly see how the valves fit together and how the lower valve is much smaller and flatter than the convex upper valve.

Graphea, navia (from Triasic 210mya - Jurassic 150mya
Pycnodonte Oyster Fossil, Upper and Lower Valves (Cretaceous 135 Million-Years-Ago to Miocene 40mya)

Today, the small oyster fossils shown above and below are found in abundance within shell-banks along North American coast lines. In their lifetime, they likely washed ashore during storms and were deposited on the beaches. Eventually, layers of sand and sediment buried them deep down cutting off oxygen and millions of year later, silica and other minerals permeated the shells and they fossilized.

Texigryphaea  oyster fossil (Cretaceous) 135mya - (Miocene) 40mya
Texigryphaea Oyster Fossil (Cretaceous 135 Million-Years-Ago to Miocene 40 mya)

Oysters For Food

Oysters have been a part of the human diet since Greek and Roman times. Today, two-billion pounds are eaten every year around the world. Oysters are prepared in a variety of ways, but raw on the half-shell is the most nutritious. Besides being an excellent source of protein, oysters contain rich sources of B vitamins, and scarce minerals such as calcium, iron, zinc, selenium and magnesium.

Graphea navia Oyster Fossil (Upper Triassic 210 Million-Years-Ago to Upper Jurassic 150 mya)

Hand Crafted Oyster Jewelry

Only one in 10,000 oysters produce a pearl, so human intervention has found a way to culture them artificially, but it still takes about six years for the oyster to complete the process. Many artists also craft beautiful jewelry using the shells of various oysters.

Exogyra, Graphea and Texigryphaea Extinct Oyster Fossil Rendering Drawing

Disclaimer: Room for error as I am about 90% certain on the identities of the small oyster shells.

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