Can someone please help me ID this possible Lactrodectus?

cacoseraph

ArachnoGod
Old Timer
Joined
Jan 5, 2005
Messages
8,325
that glassless widow looked pure black in normal light. i was even doubting it was a latro, though i couldn't think of what comb-foot could get that big

that page just shows, there is too much variability to use glasses as a species identifier
 

Widowman10

Arachno WIDOW
Old Timer
Joined
Jan 25, 2007
Messages
4,212
Nice. You have a great site on these spiders.

Elsewhere on that site you wrote:



Interesting! I've seen this in Steatoda borealis (Theridiidae) and Pityohyphantes costatus (Linyphiidae) as well. The males of those species go to work on the web almost as soon as they touch it, and don't approach her until they're finished.

You mention how closely related some of the Latrodectus species are. Are the epigynes different enough to distinguish them, or are they separated on the basis of range, behavior, appearance, etc? (There are a couple of wolf spiders in Alberta that are listed as separate species based on their range and differing courtship behaviors, even though the epigynes are identical.)
thanks! not totally sure about the epi's. that's my next scheduled thing to document :) have all the spideys, just need a good microscope and camera :rolleyes:

that glassless widow looked pure black in normal light. i was even doubting it was a latro, though i couldn't think of what comb-foot could get that big

that page just shows, there is too much variability to use glasses as a species identifier
almost pure black. you could just barely see a hint of red in normal light.

yes there is a ton of variability. but there are some pretty strong patterns across species lines. the ones that vary in patterns are anomalies. but it is true you cannot determine 100% that it is a certain species by glass alone. 99.9% though ;)




range is a big indicator of species as well. there's some range info on the same site if anyone is interested...
 

cacoseraph

ArachnoGod
Old Timer
Joined
Jan 5, 2005
Messages
8,325
i think the dorsal abdominal coloration makes looking at any other coloration pointless on this spider. yes, other species can retain some bits of juv colors... but not in this distinct two tone paint job. to suppose a random species could produce that before assuming it is variolus would be fairly insane.



also, i can't really seem to find anything that validates there being mactans' subspecies? it looks like they were syn'ed to the nominate species. not saying i don't think it is possible... i just can't find anything ruleful that says there are subspecies.
 

Widowman10

Arachno WIDOW
Old Timer
Joined
Jan 25, 2007
Messages
4,212
caco, are you referring to the "mexicanus" thing? if so, i don't think it's official, but maybe rather a dominating pattern in a local group. i believe it was dubbed mexicanus unofficially. it was however just used as an example.
 

satanslilhelper

Arachnodemon
Old Timer
Joined
May 24, 2009
Messages
734
I'm glad that I got a fairly respectable ID along with a very interesting conversation going here. I have some hourglass shots that were taken yesterday afternoon. Right before I went to work I caught one of the females hanging out upside down and got me some pretty pics!! I will upload them once I wake up later today.
 

cacoseraph

ArachnoGod
Old Timer
Joined
Jan 5, 2005
Messages
8,325
caco, are you referring to the "mexicanus" thing? if so, i don't think it's official, but maybe rather a dominating pattern in a local group. i believe it was dubbed mexicanus unofficially. it was however just used as an example.
that might have made me think of it. a number of my local bug friends also have mentioned various subspecies that seem to have existed at least in the past. i am curious cuz it seems rather likely that even a balloonable true spider couldn't lock down a species across 500+ miles of territory range. at least a few subspecies popping up at opposite extremes of range seems to make sense to me.

i have definitely heard the pattern thing from my local buddies, too. i would love to see a multigeneration study on widow offsprings that documents adult colorations one day. i suspect there can be a frustrating level of variation in one generation/eggsac
 

Widowman10

Arachno WIDOW
Old Timer
Joined
Jan 25, 2007
Messages
4,212
i suspect there can be a frustrating level of variation in one generation/eggsac
you are certainly correct there. i've seen and heard of several variations in just one sac. course, there's tons of potential when you have 500 slings in one sac ;)
 

Vespula

Arachnodemon
Joined
Jul 27, 2010
Messages
706
Beautiful spiders! I love the look of Latrodectus in general, and these girls are Gorgeous!:drool:If it helps at all, it looks like variolus to me too. :)
 

Widowman10

Arachno WIDOW
Old Timer
Joined
Jan 25, 2007
Messages
4,212
I have some hourglass shots that were taken yesterday afternoon. Right before I went to work I caught one of the females hanging out upside down and got me some pretty pics!! I will upload them once I wake up later today.
any chance we could get these posted up? refer to my first/second post, still not sure on an ID for this one. hrglass pics would help.
 

NevularScorpion

Arachnoangel
Old Timer
Joined
Jun 30, 2007
Messages
916
WOW those are sweet looking widows! how do you know that one of them is a male. all the widows in the pic looks female imo
 

Widowman10

Arachno WIDOW
Old Timer
Joined
Jan 25, 2007
Messages
4,212
from what i understand, he posted pics of the females only. you are correct, there are no males pictured.
 

buthus

Arachnoprince
Old Timer
Joined
Jun 8, 2006
Messages
1,381
Heavy white outlining of markings along with transparency remaining in her legs tells me she is immature.
 

KUJordan

Arachnobaron
Old Timer
Joined
Nov 22, 2005
Messages
344
I didn't have ime to read this whole thread so I apologize if I'm repeating others' comments or causing any redundandandancy.

they are mactans and not variolus. The dorsal chevrons are slightly yet distinctly different between the two species. These are mactans markings.

the fact you found them in a more "industrial" setting also suggests mactans, tho not as strongly as do the markings. I know many people deny that dorsal markings are not reliable as identifiers, but I beg to differ. Show me any widow that is either a mactans or variolus and show just the dorsal markings- I bet I can get it right at least 95% of the time.

an hourglass shot would be helpful, but probably just more confirmatory than anything...

hope this helps,

jordan
 
Last edited:
Top