Nephila jurassica
Encyclopedia
Nephila jurassica is an extinct species
of spider
in the family Nephilidae
, which contains the golden silk orb-weaver
s. 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
.
, 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
. 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.
Nephila jurassica is the oldest described species of the genus Nephila, extending the known fossil range of the genus back 130 million years. This makes Nephila the longest lived modern spider genus known. The next oldest species in Nephila is the Late Eocene species Nephila pennatipes from Colorado
s 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.
is 15.36 by. The total body length is approximately 24.6 millimetre (0.968503937007874 in) while the front legs reach about 56.5 millimetres (2.2 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. 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.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
in the family Nephilidae
Nephilidae
The Nephilidae are a spider family with 75 described species in four genera. They were formerly grouped in the families Araneidae and Tetragnathidae. The genus Singafrotypa was moved to Araneidae in 2002.All nephilid genera partially renew their webs....
, which contains the golden silk orb-weaver
Golden silk orb-weaver
The golden silk orb-weavers are a genus of araneomorph spiders noted for the impressive webs they weave. Nephila consists of numerous individual species found around the world. They are also commonly called golden orb-weavers, giant wood spiders, or banana spiders...
s. The species is known only from the Middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
Jiulongshan Formation, part of the Daohugou Beds
Daohugou Beds
The Daohugou Beds are a series of fossil-bearing rock deposits located in northeastern China, with the type locality around Daohugou village of Ningcheng County south of Chifeng, Inner Mongolia, but extending into southwest Liaoning. The rocks are grey, finely bedded, lacustrine, sandy mudstones...
, near the village of Daohugou in Ningcheng County
Ningcheng County
Ningcheng County is a county of southeastern Inner Mongolia, People's Republic of China, bordering Liaoning province to the east. It is under the administration of Chifeng City.-References:*...
, northeastern China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
.
History and classification
Nephila jurassica is known only from one fossil, the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, specimen number "CNU-ARA-NN2010008" which is a mostly complete adult female. The individual is preserved as a compression fossil
Compression fossil
A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way...
in a pale grey finely laminated sedimentary tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
. 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
Capital Normal University
Capital Normal University is a university in Beijing, China. It is covered by Project 211, a policy to renew and modernize educational facilities in the People's Republic of China.-History:...
, located in Beijing
Beijing
Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. Nephila jurassica was first studied by Paul Seldon of the University of Kansas
University of Kansas
The University of Kansas is a public research university and the largest university in the state of Kansas. KU campuses are located in Lawrence, Wichita, Overland Park, and Kansas City, Kansas with the main campus being located in Lawrence on Mount Oread, the highest point in Lawrence. The...
and the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
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
Biology Letters
Biology Letters is a peer-reviewed scientific journal. It was split off as a separate journal from the Philosophical Transactions of the Royal Society B: Biological Sciences in 2005 after having been published as a supplement. Originally it was published quarterly, but from 2007 it has been...
. The etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of the specific epithet
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
jurassica refers to the age of the species.
Nephila jurassica is the oldest described species of the genus Nephila, extending the known fossil range of the genus back 130 million years. This makes Nephila the longest lived modern spider genus known. The next oldest species in Nephila is the Late Eocene species Nephila pennatipes from Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
s 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
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
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.
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 and the opisthosomaOpisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma . It is a distinctive feature of the subphylum Chelicerata...
is 15.36 by. The total body length is approximately 24.6 millimetre (0.968503937007874 in) while the front legs reach about 56.5 millimetres (2.2 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. 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.