Oct. 31, 2008 -- If it seems like spiders, scorpions, ticks and mites have been around forever, it's because they nearly have, according to new genetic research that found these arachnids first emerged at least 400 to 450 million years ago. The study, published in the latest issue of Experimental and Applied Acarology, extends the known world presence of these creepy crawlies by over 200 million years. The oldest fossil spider is 125 to 135 million years old, while the oldest fossil scorpion is around 200 million years old. These invertebrates could even have emerged much earlier than this latest study determined. "A horseshoe crab dating to 475 million years ago provided one of our anchor dates, and this crab actually looked quite modern, as did a Devonian period (416 to 359 million years ago) mite that was one very modern-looking mite," co-author Marjorie Hoy told Discovery News. Hoy, a University of Florida entomologist, added, "I don't think the individuals just suddenly appeared on Earth, so it's likely these invertebrates are even older than we estimated." Related Content: Slide Show: Scary Landscapes Discovery News Blog: Born Animal Spiders Get Flashy at Night to Lure Prey She and colleague Ayyamperumal Jeyaprakash, who is a University of Florida senior biological scientist, obtained complete genetic sequences for the mitochondria of 25 different invertebrates, including four spiders, two mites, three scorpions, soft and hard ticks, and other members of an arachnid group that's known as the Chelicerata lineage. Jeyaprakash identified genetic sequences common to the organisms. The researchers then used high tech computer programs to calculate how much time passed since the sequences evolved from a common origin. Since such sequences can be very long, computer processing times for some analyses required up to a month on the scientists' well-used MacPro. The study represents the first large-scale attempt to use genetic methods to make projections about when arachnids first evolved. In addition to the age discovery, at least two other major findings about spiders, scorpions, ticks and mites emerged from the research. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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