Scientists study 444-million-year-old marine fossil with preserved internal organs
The newly named species Keurbos susanae retains muscles and tendons despite lacking its head, legs and outer shell.
Scientists have studied a 444-million-year-old marine fossil that preserves internal structures like muscles, tendons and guts while losing its head, legs and outer shell, according to the Times of India.
The fossil has been identified as a new species named Keurbos susanae. University of Leicester palaeontologist Sarah Gabbott named the species after her mother, Sue, following 25 years of research.
The research, published in Papers in Palaeontology on 26 March 2025, describes the specimen as an exceptionally preserved marine arthropod. Unlike most arthropod fossils that show hard external features, this fossil retains an extraordinary record of its internal anatomy in three dimensions.
The main specimen is approximately 43 centimetres in length and features a trunk with 46 segments that become narrower towards the rear. Researchers identified internal supporting frameworks and muscle-linked features, though the creature's exact evolutionary branch remains uncertain.
The specimens were discovered in the Soom Shale in South Africa's Western Cape Province, located about 250 kilometres north of Cape Town. This geological formation dates back to the Late Ordovician period, which ended around 444 million years ago.
The fossil's unusual preservation occurred in an environment with low oxygen levels. While much of the external body is missing, mineral replacement captured delicate anatomical structures that normally decay shortly after an animal dies.