Acta Arachnologica
Online ISSN : 1880-7852
Print ISSN : 0001-5202
ISSN-L : 0001-5202
A New Eyeless Spider (Archerius: Theridiidae) from Shobudo Cave, Kochi Prefecture, Japan
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1959 Volume 16 Issue 2 Pages 30-33


Till now, about a score of cave-inhabiting spiders have already been reported from some caves in Japan by K. Kishida, J. Ishikawa, T. Komatsu, T. Uyemura, T. Habe, S. Nomura, S. Ueno and T. Yaginuma.
Although in these spiders are sometimes found various stages of reduction of eyes, no eyeless spider has yet been recorded. Recently, however, the author had an oppotunity to examine a small spider, collected from a hollow in a limestone cave in Kochi Prefecture, which shows apparently a form for isolated dwelling in a dark cave by lacking eyes. In this paper is reported a new eyeless species of Archerius; which, however, has eyes in American species.
The specific name was given in honour of Mr. Kiyoshi Nakahira who discove-red the present species.
(_??_) Cephalothorax convex, longer than wide. Anterior part of the head roun-ded. Clypeus vertical. Eyes entirely wanting, and even their vestiges invisible, only a few hairs remaining. All grooves or furrows on carapace obsolete. Tarsus of palp without claw. Upper margin of fang furrow with three teeth, lower also with three but small. Sternum as long as broad. Maxillae wide, converging in front of labium. Labium fused to sternum.Legs 4. 1. 2. 3, scopulae and claw tufts wanting. Posterior legs with weak spines on each tibia. Tarsus longer than metatarsus. Tarsal claws three; upper claws with four extremely small teeth increasing distally in length. These teeth unrecognizable without careful observation. Serrated brisles as usually seen in Theridiidae, wanting, but hairs on the undersid-es of all tarsi and metatarsi weakly serrated. Abdomen long oval, with many reddish brown sclerotized spots with a hair on each, scattered closely on the en-tire dorsum. Anterior part of abdomen overlapping the hind part of thorax. A ventral scutum extending forward to encircle the pedicel, covers 2/3 of the vent-er, and with a pair of small oval holes of spiracles in anteriar part. Posterior tracheal spiracle transverse, a little advanced from spinnerets, and near to epi-gynum situated at the end of the scutum. Spinnerets sorrounded by mammillary wall. Colulus small but distinct. Total length 1.8mm.
Colour: Body and appendages yellowish brown. Margin of sternum, ventral scu-tum and posterior tracheal spiracle reddish brown. Abdomen yellowish brown with many reddish brown spots.
Locality and Date: Shobudo cave, Kochi Prefecture, Japan.
(Collected by Mr. Nakahira, Aug. 8, 1958)
Remarks: Present specier belongs to the genus Archerius which was establis-hed by H. W. Levi 1957, and is distinguished from Archerius mendocino LEVI by the absence of eyes, small colulus and the shape of eyigynum. The characteristics of present species indicates also those of Symphytognathidae which is sometimes treated as distinct family. The author has another species of which was identified by H. W. Levi, and wil be described by prof. OI in near future.

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