Trap-door spider - Totategumo (English spelling)

This is a general term for spiders that live mainly underground and have doors at the entrances to their homes, such as the families Trapdooridae and Trapdooridae, of the Arachnida class of the Araneae order of the Araneae family.

The representative species of trapdoor spiders in Japan is the Japanese trapdoor spider Latouchia typica , which is found from the central Tohoku region south to Kyushu (the number in Shikoku is unknown). They dig vertical holes in the ground and make a hinged door at the entrance. Females reach a maximum body length of 15 mm, while males are slightly smaller. Their cephalothorax is brown and their abdomen is a dark purple background with white herringbone-shaped markings. They are found under the edges of houses, on the edge of stepping stones in temple grounds, and between stone walls. Their distribution is wide, but they are found in large numbers in localized areas. The Japanese trapdoor spider Ummidia fragaria has emerged from underground and makes a bag-like dwelling about 30 mm in a crack in the bark of an old, moss-covered tree (such as camphor or cedar), with a door at the entrance as well. They sometimes nest on stones or between stones and the soil, but the thick spines on their upper jaws that they use to dig holes are a vestige of their underground lifestyle. They are found throughout Japan, except Hokkaido. Other species found in the Ryukyu Islands include the Okinawa Trapdoor Spider and the Miyakojima Trapdoor Spider. Spiders of the family Trapdoor Spider generally live in horizontal caves with double-leaf doors at the entrance. Morphologically, they are characterized by a sideways central cavity in the cephalothorax. The Trapdoor Spider is found in Honshu (Tohoku, Kanto, Chubu, and Kinki regions), while the Siberian Trapdoor Spider is found only in Hokkaido. These two species are noteworthy as remnant species that migrated south along with their North American relatives. The family Kimulagidae is also sometimes treated as a trapdoor spider.

[Takeo Yaginuma]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

節足動物門クモ形綱真正クモ目のトタテグモ科、カネコトタテグモ科などの、おもに地中生活をし、住居の入口に扉をつけるクモの総称である。

　日本のトタテグモ科の代表種はキシノウエトタテグモLatouchia typicaで、東北地方の中央部以南九州まで分布する（四国は不詳）。地中に縦穴を掘り、入口に蝶番(ちょうつがい)式の片開き戸をつける。体長は雌の最大が15ミリメートルで、雄はそれより一回り小さい。頭胸部は褐色、腹部は黒紫色の地に白い矢筈(やはず)状の斑紋(はんもん)がある。人家の縁の下、寺院の境内の踏み石のきわ、石垣の間などでみられる。分布は広いが、局地的に多産する。また、キノボリトタテグモUmmidia fragariaは地中から地上に進出したもので、苔(こけ)むした古木（クス、スギなど）の樹皮の割れ目に30ミリメートルぐらいの袋状の住居をつくり、入口にはやはり扉をつける。ときには石の上や石と地面の土の間に営巣することもあるが、上あごに穴を掘る太い棘(とげ)があるのは地中生活の名残(なごり)である。北海道を除く全国に広く分布する。琉球(りゅうきゅう)諸島には、このほかにオキナワトタテグモ、ミヤコジマトタテグモがいる。カネコトタテグモ科のクモは、一般に住居は横穴式で入口の扉は両開き戸である。形態的には頭胸部の中窩(ちゅうか)が横向きであるのが特徴。カネコトタテグモは本州（東北、関東、中部、近畿の各地方）に分布し、エゾトタテグモは北海道だけに産する。この2種は北アメリカの近縁種とともに南下した残留種として注目される。キムラグモ科もトタテグモとして扱われることがある。

［八木沼健夫］

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