Trilobite Ellipsocephalus hoffi – Jince, CZ

Trilobites were marine arthropods that inhabited the world’s oceans for more than 270 million years – from the early Cambrian to the end of the Permian period (approximately 521 to 252 million years ago). They are considered one of the oldest and longest-surviving complex life forms in Earth’s history. Their name is derived from the three-lobed body plan ("trilobite" = three-lobed), consisting of a cephalon (head), thorax (middle body segments), and pygidium (tail). Trilobite fossils are found all over the world, but some locations – such as the Barrandian area in the Czech Republic – rank among the most important. The famous species Ellipsocephalus hoffi originates from this region.

Ellipsocephalus hoffi is a representative of the Middle Cambrian period and is one of the best-known trilobite species found in the Jince area of Central Bohemia. It is a small trilobite with a characteristically oval body, about two to three centimeters long, with both the cephalon (head) and pygidium (tail) rounded. The genus Ellipsocephalus is known in paleontology for its simple morphology and relatively small number of thoracic segments, suggesting it evolved in an early stage of trilobite development.

Color variations and patterning

Most preserved specimens of Ellipsocephalus hoffi have a fossil shell colored dark grey to black, which results from mineral processes that occurred during fossilization in sediments rich in organic matter and iron. Color variations are not as prominent in this species as in some later trilobites, but careful preparation can reveal subtle lighter tones or small spots reflecting the original surface texture. More delicate structures such as eye lobes or fine segment lines are often well preserved, allowing observation of detailed anatomical features.

Geological characteristics

The Jince locality is part of the so-called Barrandian area, a geological region renowned for its abundance of fossils from the early Paleozoic era. During the Cambrian, the area of today’s Czech Basin formed the edge of a shallow sea where fine muddy sediments accumulated, containing remains of marine organisms. These fine-grained sediments allowed for relatively good preservation of fossil material, including trilobites. The Cambrian in the Jince area is characterized by the so-called Jince Formation, which contains not only Ellipsocephalus hoffi but also other trilobites such as Paradoxides and Hydrocephalus, indicating a diverse marine ecosystem in that ancient time.

Comparison with other localities

Within the Barrandian, other famous fossil localities include Skryje and Týřovice, though their trilobite assemblages belong to different geological time intervals. Ellipsocephalus hoffi is specifically typical for the Middle Cambrian layers in Jince, which differ from other areas both in sediment composition and the presence of specific trilobite genera. On a global scale, similar Cambrian trilobites can be found in places such as Morocco or the United States (e.g., Burgess Shale in Canada, although it represents a different trilobite fauna from the genus Ellipsocephalus). This makes the Jince layers extremely important for comparing evolutionary lines of early trilobites.

Availability and collector value

Historically, Ellipsocephalus hoffi has been relatively commonly found, as the Jince layers have long been studied by both professional paleontologists and amateur collectors. With some luck, small fragments of shells can still be found in surface quarries or on old spoil heaps, but intact and fully preserved specimens with clear details have become increasingly rare. On the collectors’ market, trilobites from Jince appear less frequently due to their cultural and paleontological significance, and their price can be higher – especially for perfectly preserved pieces with precise preparation.