Friendly Neighborhood Spiderman

by Belle Waring on October 25, 2005

This is a very fun NYT Science Times article about one Norman I. Platnick, who has “discovered more than 1,200 new spider species, several dozen new genuses and a couple of new families.” In addition, he has been a major contributor to cladistics, “a method of sorting organisms based on the evolutionary features they share, all derived from their closest common ancestor.” I have to say that spiders freak me out; my nightmares often feature the banded-legged garden spiders of my South Carolina youth, totally harmless but swiftly enlarging through the summer to the size of my small spanned hands. Needless to say, equatorial rain forests have got some damn big spiders as well. I can recall an early morning hike through the small remaining section of primary rainforest in the Singapore Botancial Gardens, during which I saw the two biggest spiders of my life in high webs. Like, really big. Much bigger than tarantulas in the Carribbean, say. I spent the rest of the walk with my hand outstretched in front of my face; what if I were the first one along this path? Still, I have always been willing to catch even big wolf spiders under a glass, then slide a piece of paper beneath it, and throw them outside. I hope the arachnidae appreciate that. And hey, at least I don’t live in Australia! (This reminds me of the Terry Pratchett novel The Last Continent. Death and his butler attempt to retrieve information about the poisonous creatures of “Four Ecks” and are nearly crushed under an avalanche of books. Once they have decided to ask about the non-lethal animals a single sheet comes fluttering down from a high shelf, bearing the legend: “some of the sheep”.)

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The Sixth International
10.25.05 at 4:00 pm

{ 22 comments }

1

Alan 10.25.05 at 8:22 am

The land down under isn’t that bad really. Apart from crocodiles, nearly all of the deadly creatures here are small enough to pick up with one hand. Bring gloves :)

2

Alan 10.25.05 at 8:31 am

Sorry, I forgot about the whistling spider, Selenocosmia crassipes. Bring chain mail gloves.

3

Luis Villa 10.25.05 at 8:41 am

Alan: and the snakes?

4

Stephen 10.25.05 at 9:03 am

This reminds me of a question I asked Henry Disney – an expert on Phoridae. He seemed to publish new species quite frequently.

Q. Why are there so many species of beetle? (talking about phoridae at time)

A. Because lots of people study beetles.

5

Steve LaBonne 10.25.05 at 9:22 am

There’s some truth in that, but it’s also the case that there really are a hell of a lot of species of beetles. Every biologist knows the famous quip by the great geneticist J.B.S. Haldane, who when asked by some befuddled clergyman what science could tell us about God’s plan for His creation, answered,”He must have an inordinate fondness for beetles.”

6

Kieran Healy 10.25.05 at 9:27 am

Alan: and the snakes?

When we moved to Australia the first time, we were told not to worry about the poisonous snakes, because the spiders had killed most of them.

7

Belle Waring 10.25.05 at 9:54 am

what about the goddamn octocpuses, then?

8

Mrs Tilton 10.25.05 at 10:39 am

How nice to see Platnick get a tip o’ the hat. He is a demigod to anybody interested in spiders (and, especially, spider systematics). Rather unfairly savaged by Dawkins some years ago.

Belle, if you saw really big spiders in high webs, might they have looked like these? Nephila; superficially similar to your Carolina garden spiders, but from a different (though related) group. Entirely harmless to you. They’re not really bigger than tarantulas (unless perhaps one is thinking of the smaller tarantulas), but still very big as spiders go.

9

David Margolies 10.25.05 at 10:53 am

Spelling flame:

“several dozen new genuses…”

‘genera’

10

Jeremy Osner 10.25.05 at 11:19 am

Mr. Margolies — is “species” its own plural? Always wondered.

11

jet 10.25.05 at 11:50 am

Don’t forget the fark’n jellyfish:

The stinging process of the nematocyte resembles a jack-in-the-box mechanism….This pressurized process has a high internal hydrostatic pressure of 150 atm that causes the ejection to occur within 3 milliseconds, with an acceleration power of 40,000g and a force of penetration of 20-33 kPa. In addition, the nematocyst is capable of penetrating up to a depth of 0.9 mm. This depth deposits the toxin into the microvasculature of the dermal tissue to be absorbed into the systemic circulation and anchors the tentacles to the prey.

12

phil 10.25.05 at 12:47 pm

“Species” is indeed its own plural. I never forgave my grade-school English teacher who tried to fob “specie” off on us on one occasion. (And he wasn’t discussing monetary policy.)

13

Jeremy Osner 10.25.05 at 2:30 pm

Heh — I saw ‘specie’ for the first time when I was reading a Melville pirate story (Benito Cereno) this summer, and had to look it up.

14

John Quiggin 10.25.05 at 3:08 pm

No mention yet of sharks (as with spiders, the crocs keep them down in tropical parts), paralysing ticks and drop bears.

15

Alan 10.25.05 at 3:46 pm

Belle, the blue ring octopus will fit easily in the palm of your hand.

Kieran, the snakes are mostly quite timid. You can pin them to the ground with a forked stick and grab them behind the head so they can’t bite, but they usually flee before you get the chance. Except for the taipan. Don’t try this with a taipan.

And for the benefit of non-Aussies here, drop bears are fictional. Paralysis ticks, alas, are not.

Apart from crocs and sharks, all the deadlies really are small enough to pick up. If you stay on dry land, you will not be eaten and excreted.

16

urizon 10.25.05 at 4:46 pm

“This is a very fun NYT Science Times article about one Norman I. Platnick, who has ‘discovered more than 1,200 new spider species, several dozen new genuses and a couple of new families.'”

And they were all living under my bed.

17

Fred the Fourth 10.25.05 at 5:00 pm

A few years ago my wife and I were planning a dive trip to the Barrier Reef and Coral Sea, along with side trips to the outback and northeastern rainforest. Handily, the very next copy of Scuba Diver mag that showed up had a listing of “World’s Deadliest Sea Creatures” or some such. Leafing through it, I couldn’t help but notice that essentially all of them were fond of that little corner of the world. Blue rings, Box jellies, various seasnakes, Bull sharks, Saltwater crocs, and on and on.
In the event, we saw lots of sea snakes (especially on the Yongala wreck, where they are quite…friendly, like kittens). Didn’t have any problems with any of them. Actually, the cool thing about those sea snakes is that they are air-breathers, living on a wreck at 90 feet. So they can’t really hide, and you get to … interact with them..Yeah, that’s the word.

18

belle waring 10.25.05 at 8:06 pm

mrs. tilton: oooog, those are the ones. the bodies are smaller than tarantulas, granted, but the “wing-span”, so to speak…in short, ooooog.

19

Thompsaj 10.25.05 at 8:38 pm

Here in South Carolina, some call them “banana spiders” though I’m not sure why

20

Kenny Easwaran 10.26.05 at 1:22 am

Actually, it’s not just the snakes and spiders and ticks and jellyfish. Even the mammals are poisonous. That is, the platypus has poisonous spines on its back legs. I hear they don’t kill you, but just cause excruciating pain for several months.

21

nnyhav 10.26.05 at 7:49 am

His logic is simple: find characteristics of spiders’ shapes that independently select the same exact group of organisms. “There are about 1.75 million species on this planet,” Dr. Platnick explained. “Select from these all the organisms with abdominal spinnerets to produce silk – about 38,000 species. Repeat this process and select all organisms with modified male pedipalps for copulation. You end up with the same 38,000.”
This congruence of characteristics unites spiders uniquely from all others, he said. Apply the concept with higher degrees of specificity, and species’ characteristics emerge.
“You start with the null hypothesis that they are all the same. It doesn’t take long to see that they are not,” he said. “Then you divide them into groups of specimens more closely related to each other.”
As he explained the process, Dr. Platnick dug out a paper describing a new species he had identified in Australia. “The differences here are in the male sex organs, or their pedipalps,” he explained. Carefully drawn in profile, one pedipalp had subtly different arrangements of sub-millimeter-sized bulbous growths.

A lepidopteric strand to this web of sense: Nabokov’s taxonomic organisation of the Neotropical Blues based on genital configuration has held up and been cladistically confirmed (cf Kurt Johnson) — cited as anticipatory though not predictive of resolution to speciation problems (and you were expecting maybe reference to Invitation to a Beheading?)

But it all goes back to Thoreau.

22

Steve Reuland 10.26.05 at 2:16 pm

“Still, I have always been willing to catch even big wolf spiders under a glass, then slide a piece of paper beneath it, and throw them outside. I hope the arachnidae appreciate that.”

They probably don’t. One thing I was surprised to learn from Rob Crawford’s Spider Myths site is that you’ve got your indoor species, and your outdoor species, and very few that are both. In other words, the spiders you find in your house didn’t come wandering in from outside; they live their entire lifecycle indoors and are not well adapted to survive outdoors. You do them no favors by kicking them out of their home. (He also points out that what you think are wolf spiders are almost certainly European house spiders, not related to actual wolf spiders.)

One thing Crawford takes great pains to explain is that nearly every species of spider is competely harmless; they don’t do any of the things that they’re accused of doing, like biting people in their sleep. Spiders live in your house for one simple reason: insects live there. The latter are almost always going to pose more of a threat to your health and happiness than the spiders, who are just trying to make a living by violently killing and eating those insects. Humans aren’t on the menu. We’re too big.

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