Ampyx (trilobite)

Ampyx Temporal range: Ordovician-Silurian ~478.6–416.0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Ampyx cetsarum group
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	†Trilobita
Order:	†Asaphida
Family:	†Raphiophoridae
Genus:	†Ampyx Dalman, 1827
Type species
Ampyx nasutus
Species
A. gongwusuensis Lee et al., 2016 A. nasutus Dalman, 1827
Synonyms
Brachyampyx

Ampyx is an Ordovician-Silurian genus of Asaphid trilobites of the family Raphiophoridae. Species of Ampyx are characterized by three extended spines on the head-shield, one spine derived from each free cheek, and one spine emanating from the glabellum.[1] Species include Ampyx linleyensis (Lanvirn-Caradoc series).[2]

Species of Ampyx grew to an average length of 1.5 inches (3.8 cm).

Collective behaviour

Linear cluster of
Ampyx priscus

Fossils of the trilobite Ampyx priscus, dating back about 480 million years ago, have been recently described as clustered in lines along the ocean floor. The animals were all mature adults, and were all facing the same direction as though they had formed a conga line or a peloton. It has been suggested they line up in this manner to migrate, much as spiny lobsters migrate in single-file queues. Or perhaps they are getting together for mating. The findings suggest animal collective behaviour has very early evolutionary origins.[3][4]

Distribution

Fossils of Ampyx have been found in:[5]

Ordovician

• Acoite, Suri, Ponon-Trehue, Sepulturas and San Juan Formations, Argentina
• Sella Formation, Bolivia
• Australia
• Canada (British Columbia, Newfoundland and Labrador, Northwest Territories, Quebec, Yukon)
• China
• France
• Iran
• Ireland
• Morocco
• Norway
• Russia
• Sweden
• United Kingdom
• United States (California, Maine, Nevada, Tennessee, Virginia)

Silurian

• Italy
• United Kingdom

See also

• List of trilobites

References

1. H H Swinnerton - Outlines of Palaeontology, Edward Arnold (Publishers) Ltd, 1972. ISBN 0-7131-2357-5.
2. British Palaeozoic Fossils - Natural History Museum 4th edition 1975. Plate 8. ISBN 0-565-05624-7.
3. Fossil 'conga lines' reveal origins of animal swarms National Geographic, 17 October 2019.
4. Vannier J, Vidal M, Marchant R, El Hariri K, Kouraiss K, Pittet B, El Albani A, Mazurier A and Martin E (2019) "Collective behaviour in 480-million-year-old trilobite arthropods from Morocco", Scientific Reports, 9: 14941. doi:10.1038/s41598-019-51012-3
5. Ampyx at Fossilworks.org