Featured Research

from universities, journals, and other organizations

Extinct giant sea scorpion gets an eye exam, with surprising results

Date:
July 10, 2014
Source:
Yale University
Summary:
Poor peepers are a problem, even if you are a big, bad sea scorpion. One minute, you're an imperious predator, scouring the shallow waters for any prey in sight. The next, thanks to a post-extinction eye exam, you're reduced to trolling for weaker, soft-bodied animals you stumble upon at night.

Sam Ciurca, a curatorial affiliate with the Department of Invertebrate Paleontology at Yale University, holds a model of a pterygotid.
Credit: Yale University

Poor peepers are a problem, even if you are a big, bad sea scorpion.

One minute, you're an imperious predator, scouring the shallow waters for any prey in sight. The next, thanks to a post-extinction eye exam by Yale University scientists, you're reduced to trolling for weaker, soft-bodied animals you stumble upon at night.

Such is the lot of the giant pterygotid eurypterid, the largest arthropod that ever lived. A new paper by Yale paleontologists, published in the journal Biology Letters, dramatically re-interprets the creature's habits, capabilities, and ecological role. The paper is titled "What big eyes you have: The ecological role of giant pterygotid eurypterids."

"We thought it was this large, swimming predator that dominated Paleozoic seas," said Ross Anderson, a Yale graduate student and lead author of the paper. "But one thing it would need is to be able to find the prey, to see it."

Pterygotids, which could grow more than two meters long, roamed shallow, shoreline basins for 35 million years. Because of the creatures' size, the long-toothed grasping claws in front of their mouth, and their forward-facing, compound eyes, scientists have long believed these sea scorpions to be fearsome predators.

But research by Richard Laub of the Buffalo Museum of Science cast doubt on the ability of pterygotids' claws to penetrate armored prey. Yale's eye study further confirms the idea that pterygotids were not top predators.

"Our analysis shows that they could not see as well as other eurypterids and may have lived in dark or cloudy water. If their claws could not penetrate the armor of contemporary fish, the shells of cephalopods, or possibly even the cuticle of other eurypterids, they may have preyed on soft-bodied, slower-moving prey," said Derek Briggs, the G. Evelyn Hutchinson Professor of Geology & Geophysics at Yale and curator of invertebrate paleontology at the Yale Peabody Museum of Natural History. Briggs co-authored the paper.

Victoria McCoy, a Yale graduate student, developed an innovative mathematical analysis method to understand the properties of the sea scorpions' eyes. Yale also used imaging technology with backscattered electrons on a scanning electron microscope to reveal the eye lenses without damaging the fossils. The team compared the results with the eyes of other extinct species during the same period, as well as modern-day species such as the horseshoe crab.

Although the data couldn't be used to determine nearsightedness or farsightedness, it revealed a basic visual acuity level for the sea scorpions, which had thousands of eye lenses. "We measured the angle between the lenses of the eye itself," Anderson said. "The smaller the angle, the better the eyesight."

Unfortunately for pterygotids, their eyesight proved less than exceptional, note the researchers. In fact, their vision worsened as they grew larger. It certainly wasn't on par with high-level arthropod predators such as mantis shrimp and dragonflies, said the scientists.

"Maybe this thing was not a big predator, after all," Anderson said. "It's possible it was more of a scavenger that hunted at night. It forces us to think about these ecosystems in a very different way."

The Yale team's vision testing methodology may prove instrumental in understanding how other species functioned, as well. "You could use it on a number of different organisms," according to Anderson. "It will be particularly useful with other arthropod eyesight examinations."

Former Yale postdoctoral fellow Maria McNamara of University College Cork also co-authored the paper. The research began as a project in a fossil preservation class Briggs taught at Yale.


Story Source:

The above story is based on materials provided by Yale University. The original article was written by By Jim Shelton. Note: Materials may be edited for content and length.


Journal Reference:

  1. R. P. Anderson, V. E. McCoy, M. E. McNamara, D. E. G. Briggs. What big eyes you have: the ecological role of giant pterygotid eurypterids. Biology Letters, 2014; 10 (7): 20140412 DOI: 10.1098/rsbl.2014.0412

Cite This Page:

Yale University. "Extinct giant sea scorpion gets an eye exam, with surprising results." ScienceDaily. ScienceDaily, 10 July 2014. <www.sciencedaily.com/releases/2014/07/140710183616.htm>.
Yale University. (2014, July 10). Extinct giant sea scorpion gets an eye exam, with surprising results. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2014/07/140710183616.htm
Yale University. "Extinct giant sea scorpion gets an eye exam, with surprising results." ScienceDaily. www.sciencedaily.com/releases/2014/07/140710183616.htm (accessed September 17, 2014).

Share This



More Plants & Animals News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chimp Violence Study Renews Debate On Why They Kill

Chimp Violence Study Renews Debate On Why They Kill

Newsy (Sep. 17, 2014) The study weighs in on a debate over whether chimps are naturally violent or become that way due to human interference in the environment. Video provided by Newsy
Powered by NewsLook.com
Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins