Spiders of Sungai Tawau

Cheiracanthium sp COMPLEX
Cheiracanthium sp COMPLEX is a sac spider.

Sac spiders construct a silken tube or sac in a protected area, such as within a leaf, under landscape timbers or logs, or at the junction of a wall and ceiling, and they use this sac as their daytime retreat. This is how the spider derives its common name, sac spider. These spiders do not build webs.

Sac spiders are known to prey on caterpillars.

This female spider has a deformation in ALS (anterior lateral spinnerets) - only one single spinneret instead the normal pair of two.

Cheiracanthium sp COMPLEX
Genus : Cheiracanthium

Found on 22 August 2014 evening at Tawau Sport Complex's jogging ground. Tawau Sport Complex is just beside the lower Tawau River.

Actual species name unidentified. We gave a temporary name sp COMPLEX because it was found at Tawau Sport COMPLEX.

Cheiracanthium is a genus of spiders in the Miturgidae family. Certain species are commonly known as the "yellow sac spider" because of their colour.

The size of this female Cheiracanthium sp COMPLEX :

Length including fangs is 14mm

Eight eyed spider : Eyes of  Cheiracanthium sp COMPLEX

This species has 8 similarly sized eyes distributed in 2 horizontal rows. The lower middle 2 eyes are slightly larger.

Cheiracanthium sp COMPLEX


Fangs 獠牙

Sternum 胸骨

Book lung 本書肺

Epigastric furrow 上腹部溝


Spinnerates 噴絲板



Cheiracanthium sp COMPLEX

Epigastric furrow 上腹部溝Epigynum
Book Lung Cover
Book Lung Slit

Epigastric furrow: A groove across the underside of the abdomen that marks the rear edge of the book lungs and the point of entry into the female genitalia.

The epigyne or epigynum is the external genital structure of female spiders. As the epigyne varies greatly in form in different species, even in closely related ones, it often provides the most distinctive characteristic for recognizing species. It consists of a small, hardened portion of the exoskeleton located on the underside of the abdomen, in front of the epigastric furrow and between the epigastric plates.

Ventral view of the female spinnerets (View bottom of abdomen). Note one spinneret missing in the pair of ALS.

Spinnerets are finger like organs that spin thread that are at the posterior of the abdomen (end of abdomen). Posterior lateral spinnerets have conical to elongate ends.


Dorsal view (View from top of abdomen) Note one spinneret missing in the pair of ALS.

Anal Tubercle
Anal tubercle A small projection, dorsal to the spinners, carrying the anal opening.

Anal tubercle The small caudal tubercle bearing the anal opening; the postabdomen.

Most spiders have three pairs of spinnerets,
1- anterior lateral spinnerets (ALS),
2- posterior lateral spinnerets (PLS) and
3- posterior median spinnerets (PMS).

The spinnerets of spiders came in pairs. But this female has a single spinneret in the pair of ALS (Anterior lateral spinnerets). This is the first finding of spinnerets deform in Malaysia.

Spiders of Sabah  September 01, 2014 07:55:07 PM

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