Somebody could identify this spider. It is a Latrodectus species. What kind of Latrodectus is it? I fotographed it in Lybia, Marsa El Brega, 16th January 2015. I think this is new spec. for Lybia (probably even for North Africa?)?
The identity of this spider could be settled only after specimen examination, however based on known distribution of currently valid Latrodectus species, I could tend to call it as Latrodectus cinctus Blackwall, 1865. The coloration and size are quite variable in Latrodectus whichis well known to be a difficult group to study than other spiders. Even understanding epigynum in some of its species is quite difficult and a slightly different angle to look at it will end up in calling it a different species. The taxonomic history of Latrodectus is so long due to many synonymies, misidentifications and redescriptions.
The genus Latrodectus is a difficult group. The coloration or the length of the setae and number of these (historically used as valid characters) are no longer sufficient, being the genital morphology key to identify the species.
Latrodectus cinctus has been recorded in the northern region of Africa, but the aspect of this specimen is different, could be a geographic variation or another species as you suspect. In the Iberian Peninsula is recorded Latrodectus lilianae. I am attaching a link that may be of interest.
The identity of this spider could be settled only after specimen examination, however based on known distribution of currently valid Latrodectus species, I could tend to call it as Latrodectus cinctus Blackwall, 1865. The coloration and size are quite variable in Latrodectus whichis well known to be a difficult group to study than other spiders. Even understanding epigynum in some of its species is quite difficult and a slightly different angle to look at it will end up in calling it a different species. The taxonomic history of Latrodectus is so long due to many synonymies, misidentifications and redescriptions.
Any chance you collected it? I would certainly be interested in taking a closer look. At this time, I would say that live photographs alone (as attractive as your photos are) is not sufficient evidence for novel records of Latrodectus species. They are far too variable in overall color pattern and there are too many regions that are not well collected. We need more specimens in public research collections. Fresh specimens from a place like Libya would indeed be rare and illuminating.
Thanks, unfortunately I have only photos. Please, advice: tha colour pattern visible in photos, in which species may occur? (Regards to Prof Achterberg)
Yes, this is very interesting. Lia. mactans is an American species, but it is recently found in Israel. Líbya is not far from Israel. http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1966.tb03016.x/abstract
If it is L. mactans, than new spec. for the fauna of Lybia.
to me looks more like the "lugubris" morph of Latrodectus tredecimguttatus, the one found in Southern France has a similar pattern to this specimen. L. tredecimguttatus is also present in North Africa. Did you perhaps checked if it had the hourglass mark or the half moon mark under the abdomen?
Roughly, most of the "clear" patterned widow spiders as L. geometricus or pallidus for example, are considered less dangerous than the "darker" widow spiders, as mactans or hasselti, for which cases of death have been reported. Tredecimguttatus is widely considered as potentially fatal for humans, LD 50 is 0.013 mg/ mice.
The venom is normally a neurotoxic mix of latrotoxins, of which the major component is alpha-latrotoxin. This mix is has been proved effective on vertebrates and arthropods in general, crustaceans included. Latrotoxins induce Calcium-dependent channels opening, causing a massive release of neurotransmitters and, consequently, paralisys..