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qualifies as the largest spider in the world. Its eyes and
pigmentation are developed as in Heteropoda species
living outside of caves, though all species were
observed and collected exclusively in caves. It has to
be classified as troglophil at least.
Heteropoda steineri BAYER & JÄGER 2009 (Fam.
Sparassidae)
All species were observed and collected exclusively in
caves of the Xe Bang Fai area. From all species H.
steineri shows the strongest adaptation to a life in
caves, which is evident by the eyes reduced in size, the
smallest compared to all other Heteropoda species
known so far, and by the absence of pigments. It was
recorded only in the deepest and darkest sections
(midsections) of the large caves in the Xe Bang Fai
cave system. In contrast, H. maxima, which appeared
in the Xe Bang Fai cave system, too, was recorded only
in the parts relatively close to the entrances (twilight
zone, approximately 0–30 m) and far away from the
records of H. steineri.
Photo 64 - Heteropoda maxima (© H. Steiner)
Photo 65 - Heteropoda steineri (© H. Steiner)
Psechrus steineri BAYER & JÄGER 2010 (Fam.
Psechridae )
Psechridae are poorly studied, the species richness of
this genus in South-East Asia was so far misjudged.
These spiders were found in caves and also in different
habitats outside. In caves, they usually build horizontal
webs in niches of the wall, over holes or between
rocks. Psechrus species are difficult to catch because
the spiders are extremely fast in escaping when
somebody approaches the web. It requires some
patience or skill to catch them, especially when the
retreat is located in a rock crevice. Several new species
from caves have been described recently, among them
the above one, which is only known from Tham Pha
Leusi so far.
Autres araignées
Spiders are quite common in the caves of the Xe Bang
Fai area, as in all of Laos. At least seven different taxa
from the families Segasteridae, Theridiosomatidae and
yet unidentified families were collected. Further five
different forms of the family Pholcidae were collected
as well. All these still await identification.
Opiliones or daddy-long-leg spiders are typical for
the entrance areas of lao caves, three different taxa
were collected in caves of the Xe Bang Fai area, and
probably overlooked in the reminder of the caves.
Mites were collected from guano samples found in
Tham Pha Leusi, the only cave with larger
accumulations of bat guano in the area.
Scorpions
Troglokhammouanus steineri LOURENCO 2007 (Fam.
Pseudochactidae)
Three specimens of a small scorpion were collected
inside the river tunnel of Tham Xe Bang Fai, about 2 to
3 km from the entrance on alluvial soil and on a sand
bank next to the edge of the river. It proved to be a new
genus and species belonging into a family which was
thought to be monotypic to that date.
Photo 66 - Troglokhammouanus steineri (© H. Steiner)
The discovery of the type species of this family,
Pseudochactas ovchinnikovi in an isolated
mountainous region of southeastern Uzbekistan and
southwestern Tajikistan, in Central Asia, was already
remarkable, because, this scorpion displays several
characters that are unique among recent scorpions,
warranting the creation of a new monotypic family,
Pseudochactidae. No consensus has been reached yet
Xé Bang Fai - Laos Central 2007-2008 - Rapport d'activité Page 60