Castianeira dorsata. Det. J.T.Lapp 2013. Collected by myself, Joel Hallan, and Ian Wright

This spider is a good match for C. dorsata primarily by epigynum. Walking the Reiskind 1969 key for this specimen seems to allow for several paths through the key but only one path ends at a spider whose description even comes close to this spider. That species is also C.dorsata. Reiskind describes the dorsal abdomen as having a longitudinal red band. Perhaps all of his 5 females did, but this one does not have a contiguous band. However, I noticed that the band does appear more contiguous in the preserved specimen, so I've included a photo of that. The spider is however a good match for the description of the ventral abdomen, which includes the words, "two beaded stripes from sides of epigastric furrow to the posterior sclerite." I've posted a ventral shot of the spider in alcohol for comparison.

Aside from the noticeable difference in abdominal pattern, I am not finding any fo the required "brownish" setae between the orange setae on the longitudinal stripe and the black setae that surrounds it. The anterior dorsal sclerite does have white setae as required for dorsata.

The date given is the date collected as a penultimate female. The spider became an adult within a few days of July 29th. We also found a penultimate male only minutes and feet away from this specimen, which I also collected and raised. Here are photos of the adult and penultimate of that male. Notice how similar the penultimates are.



This is a new record for Texas, per Allen Dean's list. As of the Reiskind 1969 paper, there appear to only be a few records from far-south Arizona, as well as records in Mexico. Even if it's not C. dorsata, it's clearly in the "dorsata group" per Reiskind. Nothing in the dorsata group is reported for Texas, so it's still new for Texas.

Further supporting the likelihood that this is C. dorsata, BugGuide contains a number of photos of spiders that look just like mine -- immature and adult forms, male and female -- that are found in Pima County, Arizona, which is on the border with Mexico like the other Arizona counties where Reiskind reports C. dorsata to be found.