The primary goal of the Paleopanchax project is to gather knowledge on the origin of the Cyprinodontiformes. The first results of this project are presented in 'The Fossil Cyprinodonts'; a comprehensive catalog which will be published December 12, 2026. It includes all fossil species described before October 30, 2026.

Paleopanchax is a fictive name for the HyCA (Hypothetical Common Ancestor) of all cyprinodonts. A combination of Paleo (from Paleolithic = older or ancient, especially relating to the geological past) and Panchax (meaning 'fish'), referring to the former genus. Panchax is commonly used in several cyprinodont genera.

'The Fossil Cyprinodonts' contains a handy quick scan to identify fossil species of Cyprinodontiformes, also known as killies. (Click here for details and ordering)

As stated in the catalog new fossil species and, based on taxonomic decisions, synonimised species described since October 2026 are listed here, in this section of my website.

See the full list of species and synonyms as listed in 'The Fossil Cyprinodonts' here. For data on recent, extant species I refer to the excellent database Killi-Data Online by Jean Huber.

The Fossil Cyprinodonts

Atlas of Fossil Cyprinodontiform Fish
Volume 1: 1818 - 2026.

Available: December 12, 2026. PRE-ORDER NOW!

Story

Killifish, particularly live-bearing guppies and swordtails, have been the most popular aquarium fish for years. Many books showcase the beautiful, colorful species that live on all continents today, with the exception of Australia. What – until now - has remained underexposed are the fossil species: the origin of the Cyprinodontiformes, the scientific name for killifish. The Fossil Cyprinodonts is a semi-scientific work that, for the first time, brings together all of the more than 150 fossil killifish described to date in a single complete, full-color book.

What to expect

The Fossil Cyprinodonts is a full-color catalogue of nearly 250 pages describing every known fossil killifish from the first described species, Poecilia lametherii, to the latest description before this book is published (all species described before October 30, 2026 will be included). Every family and species has its own profile, a lay-out similar to the well-known series "A World of Killies" by Ruud Wildekamp. Profiles include:

• Accurate image of each species as it may have looked in life.
• Description and distribution.
• Remarks and notes on possible relations.
• Family overviews showing relations between the (fossil and recent) Cyprinodontiformes.
• Key to the species

Who is it for

This book is a reference database of every known fossil killifish species, useful for scientists / taxonomists (e.g. to determine relationships or minimal age of a certain group – and to avoid using already existing names…); useful for museum staff to help determine their specimens; useful for fish fossil collectors to determine the species they have found, bought or own and, last but not least, interesting for killifish enthusiasts all over the world who want to know more about the ancestry of their beloved fish. 

Pre-ordering, with exclusive extras, is possible through Kickstarter starting November 15. Don't miss it!

Click here to pre-order this book on Kickstarter. Funding starts November 15 and runs till November 30, 2026.

Scheduled for publication December 12, 2026