Leedsichthys was a very large prehistoric saltwater fish which lived during the middle and late Jurassic Period, circa 165-150 million years ago. It was named in 1889 in honor of Alfred N. Leeds who found the first specimen.

Leedsichthys belonged to an extinct group of fish called the pachycormids. It is currently regarded as the largest bony fish ever, but just how big was it? Well, that’s difficult to answer because it’s known only from fragmentary remains. However, the largest specimen (NHMUK PV P10156) is estimated to have measured 50 feet long, making it as big as a modern-day Whale Shark. It also likely filled a similar ecological niche because Leedsichthys is regarded as being a filter-feeder.

Fossils which have been ascribed to this genus have been found in England, France, and Germany, but also in Chile and Argentina, indicating that it had a worldwide distribution.

The reconstruction that you see below is based upon the related but much smaller pachycormid genera Pachycormus and Orthocormus. The drawing was made with No.2, No.3, and colored pencils on printer paper. The coloration that I gave it is based upon the modern-day Basking Shark, which is another large filter-feeding fish.

Leedsichthys problematicus. © Jason R. Abdale (February 9, 2023).

Keep your pencils sharp, everyone.

Categories: Paleontology, Uncategorized

Tags: Argentina, art, Chile, England, Europe, fish, France, Germany, Jurassic Period, Late Jurassic, Leedsichthys, Mesozoic, Middle Jurassic, pachycormid, Pachycormidae, paleo-art, paleontology, Prehistoric, South America