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Bolas spider - Mastophora leucabulba

Bolas spider - Mastophora leucabulba
World Birding Center HQ at Bentsen-Rio Grande Valley State Park, Hidalgo County, Texas, USA
December 22, 2006
A few of us were admiring and photographing an extremely rare butterfly (Strophius Hairstreak; I'll get around to posting it eventually) when I noticed this guy lurking on a nearby leaf of the same yellow-blooming Lantana shrub. Have seen the critter only 2-3 times. I am guessing at the species ID based on comments posted here on BugGuide about another individual photographed in Texas, not too much further north....

Images of this individual: tag all
Bolas spider - Mastophora leucabulba Bolas spider, side view - Mastophora leucabulba Bolas spider, dorsal view - Mastophora leucabulba

Mastophora leucabulba?
Looking at Levi's drawings for these species with the Balabans it appears that this spider matches M. corniger better than M. leucabulba. See page 343 & 359 here.

M. leucabulba is distinguished by the enlarged tubercle between the median eyes. I'm not sure what I see on these images... do you have any others that show the median eyes better?

I am afraid that these images are the best that I had. I am reluctant to disagree with someone like Allen Dean, who has been studying spiders since my age was in the single digits. But that said, looking at the book pages you suggested, this individual and the other one that I posted on the Guide as M. leucabulba both seem to match the illustrations of cornigera more closely....

I hear you
I am also reluctant to argue with Allen Dean's determination. I find that local expertise trumps comparing images in a guide. Maybe you could contact him and ask if he can offer any tips on how we can separate these two species by field markings.

Moved from Mastophora cornigera based on comments provided by Dr. Allen Dean of Texas A&M University. Thanks Allen!

idea on this one?

Dr. Dean seconds the opinion posted there on behalf of Dr. Vincent, that the Nueces County spider is M. cornigera. I'll reassign those photos from genus to species.

Joshua S. Rose, Ph.D.
Program Specialist
World Birding Center
Bentsen-Rio Grande Valley State Park
956-584-9156 x 236

Great addition to the guide! Does this mean that the images from California which look so different are not cornigera?

other images
I actually do not think the ones from California look very different than mine. The differences I see look more like the consequences of different lighting conditions and different views of the spider than differences in the critters themselves.

Note also the one currently listed in the genus section, but ID'd to this same species by someone from California.

BTW, I'm finally posting these photos, over four months after taking them, because central Texas naturalist Brush Freeman photographed another Mastophora in Elgin, TX. Brush suspects his to be a different species, among other things it has smaller humps, plus he got photos of the egg masses; maybe I'll post his too...

Joshua S. Rose, Ph.D.
Program Specialist
World Birding Center
Bentsen-Rio Grande Valley State Park
956-584-9156 x 236

forget there are 15 species in the genus.

Moved from Bolas Spiders.

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