Latrodectus ID?
Greasylake

Latrodectus ID?

Caught this female in Houston, she laid a sack then died after a few months in my care. I found it dead this morning and dropped it in a vial with alcohol. I'm using 100% acetone so we'll see how it preserves colors. I was planning on making a label for it so I was hoping someone could ID it?
Houston could mean L. hesperus or L. mactans. You won't be able to differentiate with photos, it would likely need to be sent to an arachnologist with a microscope and keyed out based on the morphological features. Houston would be closer to the extreme Eastern edge of L. hesperus range if they exist there (bugguide lists 'Texas', Oklahoma and Kansas as the edge of the range), so I would say L. mactans is more likely.
 
I believe it is the mactans. The hesperus does not have markings along the back, at least the ones in all the areas I have encountered hesperus (Utah, Nevada, and California).
 
@Ungoliant But yet L. variolus does not have a full hour glass marking on the ventral abdomen. Instead it has two red bars of various shapes. Sometimes these markings are trapezoidal giving an incomplete hourglass marking or it can be two rectangles that do not look like an hourglass at all. If I remember correctly, the dorsal abdomen pattern is so variable in all three USA black widow species that it can't be used to key these to species.
 
Picture of the hourglass can be found here - http://arachnoboards.com/gallery/latrodectus-sp.51594/

Based on that, I'd probably call it mactans. I've seen some weird mactans here in south TX with various markings and as far as I've been able to tell, hesperus is more out in west TX (El Paso maybe to Austin, but that's all hearsay unfortunately). Houston is far enough east that I'd say mactans and variolus are the two main options.

If you want it keyed out you can send it to me. I think I have the Latrodectus of N. America key somewhere and I have a microscope.
 

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