Leanchoilia is a megacheiran arthropod who we first met from Cambrian deposits in the Burgess Shales of Canada where they make up about 0.1% of the fauna of the Greater Phyllopod beds. These distinctive predatory arthropods are about 5 centimetres (2.0 in) in length with whip-like feelers mounted on frontal arm-like appendages. You can see the amazing level of detail in the preservation here. If we are very lucky, we sometimes from their internal organs preserved in three dimensions which adds a whole host of data to explore.
Several species are tentatively accepted today: the type species L. superlata, L. obesa and the recently revalidated and poetically named, L. persephone. Naming is a tricky business when we are dealing with fossilized specimens as ontogeny and sexual dimorphism can confuse the issue. It is not always clear if we are seeing a new species, a juvenile or noting differences between mature males and females.
Specimen: 5.2 cm. Photo and collection of York Yuxi Wang.
References:
"Burgess Shale: Leanchoilia superlata (an arthropod)". Smithsonian Institution National Museum of Natural History. Retrieved 6 July 2017.
Nicholas J. Butterfield (2002). "Leanchoilia guts and the interpretation of three-dimensional structures in Burgess Shale-type fossils". Paleobiology. 28 (1): 155–171. doi:10.1666/0094-8373(2002)028<0155:LGATIO>2.0.CO;2.
Brigitte Schoenemann & Euan N. K. Clarkson (2012). "The eyes of Leanchoilia". Lethaia. 45 (4): 524–531. doi:10.1111/j.1502-3931.2012.00313.x.
Diego C. García-Bellido & Desmond Collins (2007). "Reassessment of the genus Leanchoilia (Arthropoda, Arachnomorpha) from the Middle Cambrian Burgess Shale, British Columbia, Canada". Palaeontology. 50 (3): 693–709. doi:10.1111/j.1475-4983.2007.00649.x.
Caron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022.