''Pycnogonum'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

sea spider Sea spiders are marine arthropods of the order Pantopoda ( ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (; named after ''Pycnogonum'', the type genus; with the suffix '). They are cosmopolitan, fou ...

s in the family

Pycnogonidae Pycnogonidae is a family of sea spiders. Characteristics Most sea spiders in the class Pycnogonida have appendages on the anterior end of the body called chelifores which are used for gathering food and palps which bear sensory organs. Members ...

. It is the

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...

of the family.

Etymology

The generic name literally means “dense knees”. ''Pycnogonum'' combines the prefix ' (from ‘dense’ in Greek) with the Greek word for "knee": ().

Characteristics

Members of the genus ''Pycnogonum'' have squarish bodies with a tough integument and a few hairs. The cephalon (the anterior end of the body which is fused with the first segment of the trunk) has a long smooth

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elong ...

and a low tubercle on which the eyes are set. There are no

chelicerae The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as " jaws", chelicerae may be shaped as either articulated fangs, or similarl ...

palps Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") a ...

and these sea spiders use their proboscis to suck juices from their

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

. On the first segment of the trunk of males there are small ovigerous legs with nine segments. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e are carried around by the males on these appendages. The four pairs of ambulatory legs are short but strong, with well-developed terminal claws. The genital openings are on the second segment of the posterior pair of legs.Genus ''Pycnogonum
Marine Species Identification Portal. Retrieved 2011-11-22.

Species

The

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialis ...

lists the following

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

: *'' Pycnogonum africanum'' Calman, 1938 *'' Pycnogonum aleuticum'' Turpaeva, 1994 *'' Pycnogonum angulirostrum'' Stock, 1959 *'' Pycnogonum anovigerum'' Clark, 1956 *'' Pycnogonum arbustum'' Stock, 1966 *'' Pycnogonum asiaticum'' Muller, 1992 *'' Pycnogonum aurilineatum'' Flynn, 1919 *'' Pycnogonum benokianum'' Ohshima, 1935 *'' Pycnogonum buticulosum'' Hedgpeth, 1949 *'' Pycnogonum calculum'' Bamber, 1995 *'' Pycnogonum callosum'' Losina-Losinsky, 1961 *'' Pycnogonum carinatum'' Staples, 2002 *'' Pycnogonum cataphractum'' Mobius, 1902 *'' Pycnogonum cessaci'' Bouvier, 1911 *'' Pycnogonum clarki'' Staples, 2002 *'' Pycnogonum coninsulum'' Bamber, 2008 *'' Pycnogonum cranaobyrsa'' Bamber, 2004 *'' Pycnogonum crassirostrum'' Sars, 1888 *'' Pycnogonum crosnieri'' Stock, 1991 *'' Pycnogonum daguilarensis'' Bamber, 1997 *'' Pycnogonum diceros'' Marcus, 1940 *'' Pycnogonum elephas'' Stock, 1966 *'' Pycnogonum eltanin'' Fry & Hedgpeth, 1969 *'' Pycnogonum forte'' Flynn, 1928 *'' Pycnogonum gaini'' Bouvier, 1910 *'' Pycnogonum gibberum'' Marcus & du Bois Reymond-M., 1963 *'' Pycnogonum gordonae'' Pushkin, 1984 *'' Pycnogonum grumus'' Arango, 2003 *'' Pycnogonum guyanae'' Stock, 1975 *'' Pycnogonum hancocki'' Schmitt, 1934 *'' Pycnogonum indicum'' Sundara Raj, 1930 *'' Pycnogonum kussakini'' Turpaeva, 2000 *''

Pycnogonum litorale ''Pycnogonum litorale'' is a marine arthropod in the family Pycnogonidae, the sea spiders. It is found in the northern Atlantic Ocean, the North Sea, the English Channel and the western Mediterranean Sea. Description ''Pycnogonum litorale'' has ...

'' (Strom, 1762) *'' Pycnogonum lobipes'' Stock, 1991 *'' Pycnogonum madagascariensis'' Bouvier, 1911 *'' Pycnogonum magellanicum'' Hoek, 1898 *'' Pycnogonum magnirostrum'' Mobius, 1902 *'' Pycnogonum microps'' Loman *'' Pycnogonum minutum'' Losina-Losinsky & Kopaneva, 1973 *'' Pycnogonum moniliferum'' Stock, 1991 *'' Pycnogonum moolenbeeki'' Stock, 1992 *'' Pycnogonum mucronatum'' Loman, 1908 *'' Pycnogonum musaicum'' Stock, 1994 *'' Pycnogonum nodulosum'' Dohrn, 1881 *'' Pycnogonum occa'' Loman, 1908 *'' Pycnogonum orientale'' (Dana, 1849) *'' Pycnogonum ornans'' Stock, 1992 *'' Pycnogonum panamum'' Hilton, 1942 *'' Pycnogonum paragaini'' Munilla, 1990 *'' Pycnogonum planum'' Stock, 1954 *'' Pycnogonum platylophum'' Loman, 1923 *'' Pycnogonum plumipes'' Stock, 1960 *'' Pycnogonum portus'' Barnard, 1946 *'' Pycnogonum pusillum'' Dohrn, 1881 *'' Pycnogonum pustulatum'' Stock, 1994 *'' Pycnogonum repentinum'' Turpaeva, 2003 *'' Pycnogonum repentium'' Turpaeva, 2003 *'' Pycnogonum reticulatum'' Hedgpeth, 1948 *'' Pycnogonum rickettsi'' Schmitt, 1934 *'' Pycnogonum saxulum'' Child, 1998 *'' Pycnogonum sivertseni'' Stock, 1955 *'' Pycnogonum spatium'' Takahashi, Dick & Mawatari, 2007 *'' Pycnogonum stearnsi'' Ives, 1883 *'' Pycnogonum stylidium'' Child, 1995 *'' Pycnogonum tenue'' Slater, 1879 *'' Pycnogonum tesselatum'' Stock, 1968 *'' Pycnogonum torresi'' Clark, 1963 *'' Pycnogonum tuberculatum'' Clark, 1963 *'' Pycnogonum tumulosum'' Loman, 1908 *'' Pycnogonum uedai'' Nakamura & Child, 1983 *'' Pycnogonum ungellatum'' Loman, 1911

References

{{Taxonbar, from=Q3411182 Pycnogonids