Nephila jurassica

Nephila jurassica Temporal range: Middle Jurassic, 165 Ma PreЄ Є O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Arachnida
Order:	Araneae
Family:	Nephilidae
Genus:	Nephila
Species:	N. jurassica
Binomial name
Nephila jurassica Selden, Shih & Ren, 2011

Nephila jurassica is an extinct species of spider in the family Nephilidae, which contains the golden silk orb-weavers.^[1] The species is known only from the Middle Jurassic Jiulongshan Formation, part of the Daohugou Beds, near the village of Daohugou in Ningcheng County, northeastern China.^[1]

History and classification

Nephila jurassica is known only from one fossil, the holotype, specimen number "CNU-ARA-NN2010008" which is a mostly complete adult female. The individual is preserved as a compression fossil in a pale grey finely laminated sedimentary tuff.^[1] The fossil specimen is from outcrops of the Jiulongshan Formation exposed in the Wuhua Township. The type specimen is currently preserved in the Key Lab of Insect Evolution & Environmental Changes collections housed in the Capital Normal University, located in Beijing, China. Nephila jurassica was first studied by Paul Seldon of the University of Kansas and the Natural History Museum along with Dong Ren and ChungKun Shih both of the Capital Normal University. Their 2011 type description of the genus and species was published online in the journal Biology Letters. The etymology of the specific epithet jurassica refers to the age of the species.^[1]

Nephila jurassica is the oldest described species of the genus Nephila, extending the known fossil range of the genus back 130 million years.^[1] This makes Nephila the longest lived modern spider genus known. The next oldest species in Nephila is the Late Eocene species Nephila pennatipes from Colorados Florissant Formation. The description of N. jurassica also extended the known fossil range for the family by an additional 30 million years. The next oldest recognized member of the family Nephilidae is the Cretaceous species Cretaraneus vilaltae of Spain. Fossils of female specimens are only known from N. jurassica and N. pennatipes, all other fossil nephilids having been described from male specimens.^[1]

Description

The holotype female is fossilized with her underside facing up. Portions of all but two of the legs are missing from the fossil. The carapace of the holotype is 9.31 by 6.83 millimetres (0.367 by 0.269 in) and the opisthosoma is 15.36 by 9.5 millimetres (0.605 by 0.37 in). The total body length is approximately 24.6 millimetres (0.97 in) while the front legs reach about 56.5 millimetres (2.22 in) in length. This puts Nephila jurassica females in the same size range as modern females of the genus, and makes N. jurassica the largest described fossil spider.^[1] The tibia of the third leg features tufts of setae called gaiters, which are also found on the other three tibia. The feature of a gaitor on the third tibia is only found in Nephila and its presence along with the large size indicate the species is part of the genus.^[1]

References

1. ^ ^{a b c d e f g h} Selden, P. A.; Shih, C.K.; Ren, D. (2011). "A golden orb-weaver spider (Araneae: Nephilidae: Nephila) from the Middle Jurassic of China". Biology Letters. doi:10.1098/rsbl.2011.0228. 

External links

• Largest Fossil Spider Found in Volcanic Ash
• Biggest Fossil Spider Found