CLOSED: Please help identify two spiders in Baltimore County, MD

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RedDawgEsq Lutherville-Timonium, MD Jun 08, 2014

Hello,
A newbie here requests your help identifying two spiders recently found on my property about 20 miles north of Baltimore , Maryland, Zipcode 21093. The first image shows a large tan and brown spider in size relation to a quarter. The second shows the same spider closer-up in detail. The third image is less clear. About 3/8" long, this otherwise black spider had a dull orange (not red) mark on its back which resembled half of the classic "hourglass" mark of a black widow. Your analysis/advice will help determine whether I need to call in professional help or "leave them be". Thanks.

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Post #9862687
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Flapdoodle Minot, ND Jun 08, 2014

The larger spider is Pisaurina mira, a nursery web spider -
http://www.spiders.us/species/pisaurina-mira/

The smaller darker one is a jumping spider, most likely Phidippus audax, a very common and widespread species - http://www.spiders.us/species/phidippus-audax/ (Note: The color of the spot on its abdomen can vary from white to orange.)

Both are harmless to humans.

Post #9862809
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RedDawgEsq Lutherville-Timonium, MD Jun 08, 2014

Though it's not apparent from the photo, I believe the spot on the second spider was on its back, not the abdomen because that's what I saw as it was crawling. Does this change the identity? Looking at the link provided, and especially http://www.spiders.us/image/phidippus-audax-3/ seems to confirm the positioning, but also calls it the abdomen, so I guess that entire section of the body is called the abdomen? Is "dorsal abdomen" a more correct reference?

Post #9862845
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Flapdoodle Minot, ND Jun 08, 2014

Yes, the marking is on the back (dorsum) of the spider's abdomen. A spider's body consists of two parts, the cephalothorax and the abdomen. The cephalothorax includes its eyes, mouthparts, and legs; the abdomen contains most of the internal organs. Dorsal and ventral refer to upper and lower aspects, respectively. See http://www.cirrusimage.com/Arachnid/spider_anat_700.jpg

This message was edited Jun 8, 2014 9:03 PM

Post #9862936
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