''Cambropodus'' is a genus of Cambrian

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

from the Wheeler Shale of

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

. It contains one species, ''Cambropodus gracilis''.

Description

''Cambropodus'' is only known from a partial specimen preserving what seems to be the front end of the body. It preserves nine pairs of appendages, all uniramous and likely used for walking, which bear some similarity to the legs of

Scutigeromorpha Scutigeromorpha is an order of Centipede, centipedes also known as house centipedes. These centipedes are found in the temperate and tropical parts of every continent except Antarctica, with their distribution significantly expanded by the intro ...

. Due to their flexibility, they likely had between four and six podomeres, although the exact amount is unclear. The head also preserves two long antenniform structures. However, unlike

myriapods Myriapods () are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial. Although molecular evidence and similar fossils suggests a diversifi ...

, ''Cambropodus'' has no specialised head limbs, and instead the first two limb pairs are very similar to the rest. On the head, the limbs are more laterally attached, however they become more ventrally attached on the body. The complete animal is estimated to be roughly 2 cm long, with at least 15 pairs of appendages. The gut is preserved as a light stripe down the middle of the fossil, with no apparent gut diverticula and a likely very long midgut. No respiratory organs are preserved, therefore it likely respired through its thin exoskeleton. ''Cambropodus'' shares many similarities to the enigmatic fossil '' Portalia'' especially in the limbs, however it may be more derived and closer to Arthropoda due to the antenniform structures and apparently jointed legs. In this it resembles the

more, however it is over 75 million years older than the oldest definitive myriapod, ''

Kampecaris ''Kampecaris'' is an extinct genus comprising the Kampecarida, an enigmatic group of millipede-like arthropods, from the Silurian and early Devonian periods of Scotland and England. They are among the oldest known land-dwelling animals. They were ...

''. ''Cambropodus'' was likely

cursorial A cursorial organism is one that is adapted specifically to run. An animal can be considered cursorial if it has the ability to run fast (e.g. cheetah) or if it can keep a constant speed for a long distance (high endurance). "Cursorial" is often ...

and epibenthic, as evidenced by the structure of its legs closely matching other fast arthropods. The placement of this genus within Arthropoda is uncertain, as only the front portion is preserved, alongside no clear specialisation in head limbs that would place it within

Mandibulata The clade Mandibulata constitutes one of the major subdivisions of the phylum Arthropoda, alongside Chelicerata. Mandibulates include the crustaceans, myriapods (centipedes and millipedes, among others), and all true insects. The name "Mandibul ...

alongside the other myriapods.

Etymology

''Cambropodus'' is an arbitrary combination of letters which derives from the age of the fossil and the arthropodan affinity of the animal. The species name ''gracilis'' comes from the Latin word for "slender", referring to the legs of the animal.

References

{{Taxonbar, from=Q131429696 Cambrian arthropods of North America Enigmatic arthropod taxa Fossils of the United States Fossil taxa described in 1990