Tiny spider is a big roadblock

The spider in the picture is the same genus as the Braken Bat Cave meshweaver; because it's a juvenile, biologists can't determine if it's that specific species. However, the two spiders look identical - all the differences are internal. courtesy photo/ Jean Krejca, Zara Environmental LLC less The spider in the picture is the same genus as the Braken Bat Cave meshweaver; because it's a juvenile, biologists can't determine if it's that specific species. However, the two spiders look identical - all ... more Photo: Jean Krejca, Courtesy Zara Environmental LLC Photo: Jean Krejca, Courtesy Zara Environmental LLC Image 1 of / 11 Caption Close Tiny spider is a big roadblock 1 / 11 Back to Gallery

It's the eight-legged discovery of the millennium! An endangered species of spider not seen in more than three decades unexpectedly appeared in Northwest San Antonio two weeks ago. Biologists and science buffs, rejoice.

There's just one downside if you're an area commuter: The spider, no bigger than a dime, showed up in the middle of a $15.1 million highway underpass project on Texas 151 at Loop 1604.

And in this particular case of nature vs. man-made road, the arachnid wins.

The highway project is on hold indefinitely.

A biologist discovered the eyeless spider, called the Braken Bat Cave meshweaver, after rain exposed a 6-feet-deep natural hole in the highway's median.

She's with the firm Zara Environmental, a consultant for the Texas Department of Transportation on the project.

Construction, under way since April, was halted late last week after a taxonomist confirmed the creature indeed was the endangered meshweaver, named for the type of web it spins. It was added to the federal endangered species list in 2000, along with eight other “karst invertebrates” found only in Bexar County.

Biologists have been working alongside construction crews from the start because this area is known for its abundance of natural resources, including songbirds and rare cave animals, like the spiders, said Stirling J. Robertson, biology team leader for TxDOT's environmental affairs division.

To find a Braken Bat Cave meshweaver was a discovery of another kind altogether, akin to “stumbling on a new Galapagos Island in terms of the biological significance of the region,” said biologist Jean Krejca, Zara's president.

After the spider was collected in a bottle, it was dissected for it to be identified, Krejca said. Collecting and killing an endangered species is allowed for that purpose if done by someone with a federal permit. No other spiders have been spotted in the hole where the one was found.

Well-known hydrogeologist George Veni first identified the spider in 1980 in northwestern Bexar County, about 5 miles from the construction site. The spider's genus species classification reflects its namesake: Cicurina venii.

But the cave where Veni found the spider later was filled and now is covered by a residential development. The Braken Bat Cave meshweaver spider hadn't been seen since.

More Information The spider Name: Braken Bat Cave meshweaver Scientific name: Cicurina venii First discovered: In 1980 in northwestern Bexar County by George Veni, a hydrogeologist. It then wasn’t seen until two weeks ago, when it was found in a hole in a highway median of Texas 151 while crews were doing construction work. This second location is about 5 miles from where Veni originally found the spider. That original site was filled in. Protected: The spider was put on the federal endangered species list in 2000. Characteristics: The adult spiders are about the size of the dime. They are not known to be venomous to humans.

Until two weeks ago.

“From a conservation standpoint,” Robertson said, “this is an amazing coup.”

The entire area where the Braken Bat Cave meshweaver was found (not be confused with Bracken Bat Cave near Garden Ridge) could be a spider habitat.

Biologists have identified 19 cave features, which look like holes, while working on the underpass project. Spiders, not currently classified as endangered, were in five of those holes, which biologists will continue to analyze.

For drivers, the spider could mean some big delays in the completion of the underpass. About 80,000 vehicles a day traveled this intersection in 2010, according to TxDOT.

Before the spider surprise, U.S. Fish and Wildlife Service and the Federal Highway Administration had approved the TxDOT construction plan, which involves extending Texas 151 under Loop 1604 and connecting the road to Alamo Ranch Parkway. The underpass would eliminate traffic lights for drivers on Loop 1604.

It was set to open by next summer.

Now, both federal agencies will re-evaluate the project until they can agree on a plan that doesn't disturb any spiders potentially living in the area, or the habitat where the creatures might be bedding down.

That could mean the project continues as is, be scrapped altogether or modified. It's still too early to tell, TxDOT San Antonio District spokesman Josh Donat said.

TxDOT cares about enhancing roadway safety and easing congestion, Donat said, but “we're also good stewards of our natural resources.”

The possible presence of endangered species has threatened similar construction projects before.

In one of the most high-profile cases, in 2010 the environmental group Aquifer Guardians in Urban Areas filed a lawsuit against several agencies, including TxDOT and the Fish and Wildlife Service, challenging construction of an interchange at Loop 1604 and U.S. 281.

The project threatened the Edwards Aquifer Recharge Zone and violated the Endangered Species Act, the lawsuit said, because karst invertebrates like this meshweaver and its cave cousins were known to live there.

But construction on the project moved forward within a few months of the filing after a federal judge declined to rule on a motion for preliminary injunction filed by AGUA. At least part of the interchange will open this fall.

The unearthing of the rare spider will help biologists understand even more about the life history and habits of animals in the region, Robertson said.

“What we're talking about is the value of biodiversity,” Krejca said, emphasizing the importance of all animals in the ecosystem.

The limestone caves in the Bexar County area are like the plumbing of the groundwater system, though these particular caves aren't over the Edwards Aquifer Recharge Zone. The caves and cave species, like the spider, decompose materials and recycle them into soil and other resources that can grow new life.

“It's just a natural process,” Krejca said. “You can't someone to do that for you.”

As investigation of the spider habitat continues, biologists covered the hole where the meshweaver was found, trying to keep the temperature and humidity stable. So now, from the road drivers can't even see the small space that holds one of the most significant biological finds in Bexar County, a spider the size of a coin that can halt a multimillion-dollar construction project.

If there was a biology channel on cable TV, Robertson said, “this would be the headline.”

vdavila@express-news.net