Tibellus Sunetae [Grass Running Spider]

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(Edited)


'Ollo, Hive!

Another week, another spider. Like I said in the first post, there will be many spiders to go through. I meant to post this yesterday but life go in the way. Better late than never. So let's get into today's spider.

The lady in the photograph below is what we call a Running spider, of the family Philodromidae. They're also sometimes called false crab spiders due to the first two leg pairs being significantly longer than the others, as seen in crab spiders. Unlike crab spiders, running spiders have 8 eyes arranged in two rows that curve sharply. They also don't run like a crab (the side-ways shuffle).

• TIBELLUS SUNETAE •


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Female Tibellus sunetae

This one is a female grass running spider, of the genus Tibellus. Her species is T. sunetae. She decided my ceiling was a great place to hang out and catch mosquitoes.

I've been seeing running spiders of other genera on the ceiling and cornices for a while now, usually nestled in the fold of the cornice with their legs split flat to either side.

Catching them to relocate outside has been unsuccessful. Running spiders aren't given that name for nothing. They're fast little buggers that are quite skittish.

• GENUS •


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Tibellus sp. eye arrangement

This genus of running spider is rather unique among the South African known genera. With their long, thin bodies, and their legs not being too long, Tibellus spiders are masters of camouflage. They live on and make their egg sacs in grass where they're most protected.

For this lady, it was a matter of the long body and the leg formation typical of running spiders that pointed me to the genus Tibellus. Then it was off to the literature to find her species.

And, thanks to a revision in the Afrotropical species of Tibellus, I was able to narrow it down using the drawings, then reading through the descriptions of each species to find the one that fit. And that is Tibellus sunetae mainly for the dorsal markings, the spots, and the leg formation along with colouration.

• DESCRIPTION •


Taxon:

  • Class: Arachnida
  • Order: Araneae
  • Infra-Order: Araneamorph (true spiders)
  • Family: Philodromidae
  • Genus: Tibellus
  • Species: T. sunetae

Female

Around 5mm in body length. Leg span of approximately 10mm diagonally.

Cephalothorax:
Long and pale yellow carapace with thick darker yellowish brown band down centre, faint bands near edges, and dark spots all over. Dark setae on cylpeus and around eyes. Darker yellow tarsus on pedipalps.

Abdomen:
Long, thin, creamy abdomen that tapers to spinnerets, with thick brownish-grey line down centre, faint lines on sides, and brown spots all over dorsal side.

Legs:
Yellow with scattered dark spots and dark setae. Metatarsus and tarsus darker yellow. Leg formation of 2, 1, 4, 3.


Male

Unknown.

• ABOUT THE GENUS •


Tibellus spiders fold their legs in front and behind them so they look like a blade of grass. They will also run at the slightest suggestion of a threat. Tibellus, like most spiders, prefer to be active and abundant during the summer months and are often found here between November and April, though I spot them more readily just after the January summer rains.

They are free-living hunting spiders, essentially, meaning they don't make webs to live or breed on. They're generally yellowish to brown, and a bit of red, with what's called a "heart marking" on their abdomen. Heart, in the case of spiders, refers to a tubular artery-like organ that pumps haemolymph (sort of like blood) through their bodies. The heart runs down the centre of the dorsal abdomen, and that's what a heart marking indicates.

• NOTES •


How I said running spiders are skittish and will bolt at signs of a threat? Apparently, this female didn't get the message. However, the day I found her did have a cold front blowing through and the air was rather cold. This could have slowed her movements and response time.

This commonly happens with spiders, due to the cold freezing their haemolymph which makes it difficult for them to "pump" through their limbs. And because spiders don't have muscles, they rely on hydrostatic motion to move around. Anything that interferes with this can impair a spider. The pressures in the abdomen and cephalothorax are also fragile, which is why a wound can be deadly, even though it's small.

Fortunately, this slowed side-effect allowed me to take a couple of photos of this T. sunetae with ease, snapping some lovely detail. Further than the sluggish movement, there was nothing else to observe. She stayed in the same position all day and was gone by the next morning.



Thanks for stopping by and reading and supporting!

And remember, spiders are friends.



 

• All images are Copyright © 2022 Anike Kirsten •




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13 comments
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That was a really interesting read, and it was cool to find a post of your in the wild after the art stream XD btw, your drawing of the eyes helped a lot in visualizing it, I had imagined it all wrong from the description

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Thanks! Glad the drawing helped. Describing the features of a spider is difficult to get right without doing precises measurements and relativity. Luckily, there are pictures to help, haha.

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Hunting spiders we have occasionally stay up high for a week or more indoors, not the same as this one detailed above.

Always interesting learning about insects that arrive seasonally.

!LUV

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Ah, so the spiders in KZN are just as weird as here, haha. I find more spiders inside than I do when I go looking through the veld. Makes it easier to catalog them, at least. Even in winter, a lot of spider and insect activity, but perhaps because the Karoo is warmer than the eastern half of SA? When I was still in Sasolburg, arthropods in winter was unheard of.

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Plenty of spiders around all year, small to large you get to see them indoors and outdoors, some really make themselves at home.

Visiting Grahamstown years ago it rained profusely for a couple of days, our family told us to watch the ceilings for the large flat 'rain spiders' coming down the walls, yes the size of your fist!

My motto in life for any living thing is leave it alone... 😅

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Oh, awesome! Yeah, flatties can get quite big. Luckily they're gentle giants, haha. And funny when they wobble when they run.

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Some species very beautiful and fun to see.

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