''Heptathela kimurai'', the Kimura spider, or kimura-gumo (in Japanese), is an

Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

, found primarily in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

and named after

Arika Kimura . was a Japanese botanist and specialist in the Salicaceae, or willow family. He was a professor of botany at the University of Tokyo and at Tohoku University. Kimura was also the first director of the Botanical Garden of Tohoku University. A spe ...

, who collected it in 1920. It belongs to the sub-order

Mesothelae The Mesothelae are a suborder of spiders (order Araneae) that includes a single extant family, Liphistiidae, and a number of extinct families. This suborder is thought to form the sister group to all other living spiders, and to retain ancestral ...

(primitive burrowing spiders) and can reach up to 3 cm in length. Its burrows are covered by a camouflaged "pill box" flap. Like other species of mesothele spiders, the ancestral traits of the Kimura spider include central

spinnerets A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and are ...

and signs of segmentation on the

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

. These features are not seen on

mygalomorph The Mygalomorphae, or mygalomorphs, are an infraorder of spiders, and comprise one of three major groups of living spiders with over 3000 species, found on all continents except Antarctica. Many members are known as trapdoor spiders due to the ...

and

araneomorph The Araneomorphae (also called the Labidognatha) are an infraorder of spiders. They are distinguishable by chelicerae (fangs) that point diagonally forward and cross in a pinching action, in contrast to the Mygalomorphae (tarantulas and their cl ...

spiders, thus studying species like the Kimura spider can shed light on the evolution of all spiders. Although Kimura spiders lack venom glands, they still have strong

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 similarly ...

and can produce quite painful bites. The word ''kumo'' in

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

means ''spider''. ("Gumo" is a variation in pronunciation due to a phenomenon known as

rendaku is a phenomenon in Japanese morphophonology that governs the voicing of the initial consonant of a non-initial portion of a compound or prefixed word. In modern Japanese, ''rendaku'' is common but at times unpredictable, with certain words una ...

.) The sub-order this spider is a member of, Mesothelae, is about 400 million years old, placing the kimura spider among the most primitive living spiders. Its spinnerets are located in the middle of the body, as opposed to the more efficient location in modern spiders at the rear of the abdomen. It fixes its eggs on the surface of its burrow with

silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the coc ...

so that they are well protected. The spider also surrounds its tunnels with silk threads. When it sets out on a hunt, it pays out a line of silk behind it. This "lifeline" helps it in orienting itself.

Taxonomy

''Heptathela kimurai'' was first described by

Kyukichi Kishida was a Japanese zoologist, who published in mammalogy and arachnology. He described several spider genera or species including : * ''Heptathela ''Heptathela'' is a genus of spiders that includes the Kimura spider (''Heptathela kimurai''). Th ...

in 1920, when it was placed in the genus ''

Liphistius ''Liphistius'' is a genus of basal trapdoor spiders in the family Liphistiidae. They are found in Japan, China, and Southeast Asia. Etymology ''Liphistius'' is from the Greek ''leipo'' (lacking) and ''stios'' (equality). Biology Female body ...

'' as ''L. kimurai''. In 1923, Kishida erected the genus ''

Heptathela ''Heptathela'' is a genus of spiders that includes the Kimura spider (''Heptathela kimurai''). They are trapdoor spiders of the family Liphistiidae and are found in Japan, including Okinawa Island, Okinawa and the Ryukyu Islands. Spiders of this ...

'' for the species, as on re-examination he decided it was sufficiently distinct from spiders of the genus ''Liphistius''. The species name ''kimurai'' honours the collector,

References

*Tomo Kočar, ''Strah je okrogel in ima osem nog'' (''The fear is round and it has eight legs''), GEA 12 (2002) 7, pp 46 – 49. *Yoshikura, M. 1982. Kumo no fushigi (The wonder of spiders). Iwanami-shoten, Tokyo.

External links

{{Taxonbar, from=Q2193753 Liphistiidae Spiders of Asia Taxa named by Kyukichi Kishida Chelicerates of Japan