''Cambropachycope'' is an extinct genus of enigmatic 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 ...

that includes the single species ''Cambropachycope clarksoni'', known from the

Orsten The Orsten fauna are fossilized organisms preserved in the Orsten lagerstätte of Cambrian (Late Miaolingian to Furongian) rocks, notably at Kinnekulle and on the island of Öland, all in Sweden. The initial site, discovered in 1975 by Klaus M� ...

lagerstätten in southern Sweden. It appears to have several apomorphic features, notably including a single large compound eye.

Etymology

The genus name ''Cambropachycope'' refers to the large unilobed eye, alongside it originating from the Cambrian period. The specific name ''clarksoni'' honours E. N. K. Clarkson.

Description

Cambropachycope diagrammatic reconstruction.png, Diagram of ''Cambropachycope'' Cambropachycopidae size comparison.svg, Size diagram, compared to '' Goticaris'' Originally, ''Cambropachycope'' was determined to be approximately long based on the specimens known up to that time, however, the discovery of new specimens helped infer the new size to be approximately long (3 mm head and abdomen, and 1 mm telson). The head of ''Cambropachycope'' has an unusual anterior projection that bears a single, large

compound eye A compound eye is a Eye, visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidium, ommatidia, which are tiny independent photoreception units that consist of a cornea, lens (anatomy), lens, and p ...

. The eye structure is well preserved, and shows three layers in the

cornea The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...

, an outermost and innermost layer of transparent material and a hollow middle layer containing a dark material. This middle layer was probably used for filtering out the blue, scattered light from sunlight. There are four pairs of

appendages An appendage (or outgrowth) is an external body part or natural prolongation that protrudes from an organism's body such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface app ...

on its head. The first pair of appendages are treated as antenna, and the other pairs are

biramous The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, ...

. The mouth opens on the ventral surface in front of the second pair of appendages. Its

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

has five segments, but only the first four have a

tergite A ''tergum'' (Latin for "the back"; : ''terga'', associated adjective tergal) is the Anatomical terms of location#Dorsal and ventral, dorsal ('upper') portion of an arthropod segment other than the head. The Anatomical terms of location#Anterior ...

, and all of them have a pair of appendages, the first two being paddle-shaped. Finally there is a

telson The telson () is the hindmost division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment (biology), segment of the arthropod body, or an additional division that is not a true segm ...

Ecology

According to its eye structure, ''Cambropachycope'' was probably a

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

Classification

It is hesitantly presumed to be an early offshoot under the clade

Pancrustacea Pancrustacea is the clade that comprises all crustaceans and all hexapods (insects and relatives). This grouping is contrary to the Atelocerata hypothesis, in which Hexapoda and Myriapoda are sister taxa, and Crustacea are only more distantl ...

in original description. Other organisms, including '' Henningsmoenicaris'' and '' Martinssonia'', also discovered in

, may exist at a similar place on the phylogenetic tree. Collectively, this may have implications for the origins of the crustaceans. However, a later study placed this genus outside Pancrustacea and it was treated only as a stem-group

mandibulate 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 "Mandibulat ...

References

{{Taxonbar, from=Q104452485 Cambrian arthropods Prehistoric arthropod genera Cambrian genus extinctions

Etymology

Description

Ecology

Classification

See also

References