''Rhincalanus nasutus'' is a copepod in the family Rhincalanidae.

Taxonomy and phylogeny

''Rhincalanus nasutus'' is a species complex, composed of at least two

cryptic species In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

: one species consisting of, at the very least, individuals off of Peru, in the

Sulu Sea The Sulu Sea ( fil, Dagat Sulu; Tausug: ''Dagat sin Sūg''; Chavacano: ''Mar de Sulu''; Cebuano: ''Dagat sa Sulu''; Hiligaynon: ''Dagat sang Sulu''; Karay-a: ''Dagat kang Sulu''; Cuyonon: ''Dagat i'ang Sulu''; ms, Laut Sulu) is a body o ...

, and in the California Current, in addition to another species composed of specimens from the Kuroshio Current, the southwest Pacific, and the northern Atlantic. In its genus, it is sister to '' R. gigas''.

Description

The female of ''R. nasutus'' ranges anywhere from about in length, and the male is generally between about .

Distribution

''Rhincalanus nasutus'' is found in waters across the globe, primarily in the open ocean and

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

and slope waters.

Ecology

Life cycle and reproduction

''Rhincalanus nasutus'' is seasonal in terms of the timing of reproduction. Off of the waters of southern California, it generally reproduces from February to April, and it also can reproduce in late summer, as late as June. This reproduction is likely to be limited by food, as evidenced by this copepod failing to breed in the absence of food. Copepodite stages I through IV are usually found in the surface waters (from sea level to in depth). The abundance of individuals in the surface, however, varies seasonally: they are most abundant during the spring, and are not present during summer and autumn. Stage V copepodites and adults are generally distributed below in depth, and especially below . In seasonal waters, such as the Gulf of Aqaba, stage V copepodites go into diapause to moult into females. During this time, they also rapidly accumulate wax esters, possibly for future reproduction.

References

{{Taxonbar, from=Q6554250 Calanoida