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.‭

Another Jurassic era spider from the Mongolian Daohugou Beds is Nephila jurassica.

Further reading
-‭ ‬The oldest haplogyne spider‭ (‬Araneae:‭ ‬Plectreuridae‭)‬,‭ ‬from the Middle Jurassic of China,‭ ‬Paul A.‭ ‬Selden‭ & ‬Diying Huang‭ ‬-‭ ‬2010.





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