This critically endangered spider species is one of the smallest known at only 0.43-0.57mm. It is found in only four caves in Portugal and is threatened by limestone quarrying which has already destroyed 20% of its habitat. Unless protective measures are implemented, such as enforcing minimum distances for quarries and regulating tourism, the species is at high risk of extinction due to habitat loss and changes to the caves' microclimates.

1. Description category description
Latin name: Anapistula ataecina
Common Name: Aranha cavernícola do Frade (PT)
Photo:
Red List Category & Criteria: Critically Endangered
CITES status: NO
This is one of the smallest spiders described to date (female
size of 0.43 to 0.57 mm). It is a troglobiont (cave-dwelling)
species, only found in calcareous formations in areas with
very restricted microhabitat characteristics. Although it is a
Short species description:
very small species, this spider can easily be seen in its web
as it appears as a white spot dangling in mid-air; the web
itself is invisible. Its tridimensional web, with a sheet-like
structure, seems atypical for the family and for the genus.
This spider is known from only four caves in the Frade cave
Geographic Range: system, Sesimbra, Portugal.
Range Map: ----
The species occurs inside a Nature Park, but despite that it is
not adequately protected. Limestone quarries prevail in the
Major Threat(s): area and these expand mostly without reliable environmental
impact assessment studies prior to exploitation inside the
protected area. Approximately 20% of the cave system

2. where the species is found has already been destroyed by
nearby limestone quarries.
Within this cave system and the limestone quarries lies the
Gruta do Zambujal, a cave protected by national laws since
1979 (Decreto-Lei no. 140/79). A single visit to this cave did
not reveal any individuals of Anapistula ataecina, even
though the geological structure of this cave seems suitable
for the species. Unfortunately, the cave is now much
degraded. Changes in the internal microclimate caused by
the exposure of the cave during mining activities may have
caused the species to go locally extinct.
In addition to quarrying activities, tourism may also have an
impact on the species. The Portuguese Institute for Nature
Conservation has recently authorized tourist activities inside
Gruta do Fumo, where most specimens of this spider were
found. This authorization was granted in the absence of any
previous environmental impact assessment studies.
Despite the cave system being located inside a Nature Park
the stone quarries are expanding. Numerous conservation
initiatives were proposed by a local speleology association,
but these have not been implemented or authorized by the
national authorities:
1. To force the limestone quarries to obey the existing
laws imposing the minimum distance that any quarry
Conservation Actions: should be from protected areas or the ocean (500 m).
2. To close Gruta do Zambujal in order to restore the
natural air flow and microclimate.
3. To protect the cliffs opened by the limestone quarries
surrounding Gruta do Zambujal from erosion and to
guarantee their geological stability.
4. To establish and enforce strict guidelines for the
future touristic visits to the Frade cave system.
IUCN base link: http://www.iucnredlist.org/apps/redlist/details/176265/0
http://www.iucnredlist.org/apps/redlist/details/176265/0
http://naturdata.com/Anapistula-ataecina-38071.htm
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