Perenethis sp. [Nursery Web Spider]
Hey, there, Hive!
Ready for more spiders? This week we'll be taking a look at a curious type of spider. It's called a Nursery-Web spider. Scientifically, of the family Pisauridae. It sort of looks like some cross between a huntsman and a wolf spider.
The entire Pisaurid family is odd. There are crowned nursery spiders, that are more like ground spiders than web ones, then there are funnel-web nursery spiders, and of course, fish-eating spiders. Then they're divided further by long-bodied and short-bodied! Some Pisaurids have 2 rows of eyes, others have 3 rows, and yet others have 4 rows of eyes. Weird, weird family.
• PERENETHIS SP. •
I'm not certain what species of Perenethis this male is. He could be undescribed or perhaps a described species that hasn't been recorded in South Africa or my area (I look at spider surveys and the World Spider Catalog to see which genera and species occur here). Or he could be a variation of either P. simoni (likely, given the plain straight dark band down the centre) or P. symmetrica.
Telling the species apart in this instance would require a microscope so I'm leaving it as an unconfirmed species.
• GENUS •
At first, I thought he was a fish-eating spider, Nilus sp. of the same family, but he doesn't share the same attributes. And he didn't have a tuft of setae between his eyes which ruled out Crowned Nursery-Web spiders. His abdomen is too stout to be one of the long-bodied Pisaurids and his legs too bulky to be one of the Sheetweb or Funnel-Web Nursery spiders.
Again, a process of elimination, that left me with the genus Perenethis. It was frustrating trying to identify him because of this, and also because, according to surveys and literature, there are only two described Perenethis sp. spiders in South Africa.
• DESCRIPTION •
- Class: Arachnida
- Order: Araneae
- Infra-Order: Araneamorph (true spiders)
- Family: Pisauridae
- Genus: Perenethis
- Species: Unknown
About 11mm in body length. Leg span of approximately 30mm diagonally.
Light brown with thick dark band down centre of carapace, from eyes to abdomen, with light stripes running alongside band. Curved dark stripe near edges of carapce. Yellowish chelicerae. Tarsi of pedipalps swollen and dark. Eyes arranged in a squashed X formation.
Yellowish abdomen that tapers to point near spinnerets, thick dark band down centre with light stripes running alongside. Faint dark lines running down abdomen to spinnerets.
Pale yellowish light brown, slight darkening on patella and tibia, darker further on metatarsus and tarsus. Femurs covered in strong dark setae.
• ABOUT THE GENUS •
Perenethis is a typical free-roaming nursery-web spider. They don't make webs in which to live, though not all nursery-web spiders are wanderers. When a female Nursery-web spider makes an egg sac, she'll carry it with her, using her chelicera and pedipalps to keep it close and also bending her pedicel so that her abdomen hugs the egg sac.
She'll stay like this, not eating, until the spiderlings are almost ready. When that time arrives, she then builds a large web on which she secures the egg sac and the slings hatch and emerge and stay on this web with the mother until they're ready to leave and brave the world on their own.
The web acts as a nursery for the young ones and thus why Pisaurids are called nursery-web spiders.
• NOTES •
My experience with Pisaurids has been... brief. Because they're skittish and very sensitive to vibrations, specially those in webs, catching sight of them is generally a split-second event and it makes it really difficult to get photos. Surprisingly, this wasn't the case with this Perenethis sp. male.
He was content to stay put, drinking water using his front leg to dip and catch the water before bringing it to his mouth. And he let me take photos. I couldn't get very close due to the angle I had to hold my phone, which was precarious because I was dangling over a bucket of water...
But even when my cat came along, demanding attention, this male Pisaurid didn't run away. Perhaps he was old and tired, or just too thirsty to care. It has been a harsh summer here.