Eoplectreurys
Name:
Eoplectreurys
(Dawn Plectreurys - after the Plectreurys
genus of spiders).
Phonetic: E-oh-plec-trew-riss.
Named By: Paul A. Selden & Diying Huang
- 2010.
Classification: Arthropoda, Arachnida, Araneae,
Araneomorphae, Plectreuridae.
Species: E. gertschi (type).
Diet: Carnivore.
Size: Body length about 3 millimetres long,
leg span roughly estimated about 8-9 millimetres.
Known locations: Mongolia - Daohugou Beds.
Time period: Callovian of the Jurassic.
Fossil representation: At least seven individual
spiders.
Eoplectreurys
was (and at the time of writing still is) at the time of its
description to be the oldest known Haplogynae spider, the genus going
back as least as far as the mid Jurassic, while previous examples
were only known as far back as the early Cretaceous. This group of
spiders is identified by studying the female genitalia, which in the
Haplogynae are not sclerotized (hardened). The name Eoplectreurys
is derived from the similarity of this ancient spider to the modern
extant (still alive) genus Plectreurys. This
has seen
Eoplectreurys assigned to the Plectreuridae group of
spiders that today
are only known to live in arid desert-like environments of North
America (particularly the Western United States and Mexico) as well
as some Caribbean Islands.
The
number of eyes of Eoplectreurys is unknown, but
since it is so
similar to the plecteurid spiders in other ways, it may have had
eight like them too. If so then this would be also interesting since
most of the Haplogynae actually have six eyes, with some having as
few as four eyes. As far as sexual dimorphism is concerned, male
Haplogynae spiders tend have a round carapace (the hard upper shell
of the thorax), while the females have an elongated carapace. Out
of the seven known individual Eoplectreurys at the
time of their
description, only one had a round carapace.
With
a body length of three millimetres, a single Eoplectreurys
could
comfortably sit on your fingernail with room to spare. It should be
remembered however that this small spider was still a predator,
though one that probably hunted other small invertebrates. Assuming
that it also had a similar lifestyle to its modern extant relatives,
Eoplectreurys might have lurked under rocks and
other hard cover while
waiting for ground dwelling invertebrates to pass by.
Further reading
- The oldest haplogyne spider (Araneae: Plectreuridae), from
the Middle Jurassic of China, Paul A. Selden & Diying
Huang - 2010.
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