_3_Io______NEWSANDVIEWS------N_A_T_u_R_E_v_o_L_.3_37_2_6_JA_N_u_A_R_Y_1_9s_9 Daedalus If I had a hammer THE hammer is one of the most basic of implements. It exploits a simple newtonian principle: the deceleration of its head imposes a force on the object it strikes. In the hands of a skilled craftsman, it can crack a brick precisely in two, or make a controlled adjustment of 0.01 millimetres. Fig. 1 Composite restoration of the entire skeleton of C. hudsoni. Bar, 2 em. (From ref. L) In the hands of unskilled amateurs, how­ ever, it produces a vast global total of bent insights into the lives of the more abun­ snails. It may also have been a facultative nails, bruised thumbs, dented woodwork dant animals at this time of major faunal herbivore, raking plant food together with and smashed panes of glass. Daedalus is turnover. Some of the fissures were under its beak-like front teeth, and chopping therefore updating this palaeolithic inven­ water at the time of fossil formation. it further back in the mouth. Young tion with the most advanced electronics. The fossiliferous fissure deposits are Clevosaurus specimens have small, sharp He has been inspired by the modern dated as Late Triassic to Early Jurassic teeth which may have been used for eating thyristor photographic flash unit. This (about 220--200 million years old), the soft-bodied invertebrates such as worms. integrates the light reflected off the scene time during which the dinosaurs became Fraser' distinguishes two or more and, when enough has been received for a established, and during which most species in his material of Clevosaurus. The good exposure, quenches the flash. It all 'modern' land vertebrates arose: material is mainly disarticulated, and he happens in microseconds. In the same way, mammals,· turtles, crocodilians and examined more than 1,000 separate bones. Daedalus's electronic hammer carries an lepidosaurs. These smaller 'modern' Fortunately, he found a few more com­ accelerometer which integrates the vertebrates are best represented in the plete specimens which helped in the iden­ momentum received by the target during fissures and they have yielded significant tification of isolated elements. The second the impact. When this exactly reaches a new phylogenetic information. Clevosaurus species, C. minor, is much pre-set value, the impact is 'switched off. Fraser's find' of the sphenodontid smaller than C. hudsoni, reaching an A fast-acting trigger mechanism snatches Clevosaurus hudson? allows him to estimated total length of 150--200 mm. back the hammer head and dumps the sur­ perform a detailed analysis of this animal They have adult patterns oftooth wear, so plus momentum back into the handle and and of its relationship with other organ­ are unlikely to be juveniles of C. hudsoni. the user's arm. isms. Clevosaurus, a small 250-mm-long C. minor is found at different sites from This wonderful tool not only tames and reptile, is superficially like a modern C. hudsoni, so they are probably indepen­ directs the enthusiasm of the user: it edu­ lizard, with a slender body, long limbs and dent breeding species. cates him too. Set for a delicate task (such (probably) a long tail (Fig. 1). The teeth Other associated vertebrates from the as tapping a ceramic tile into place on its are chisel-like and, unusually for a verte­ Triassic fissures' include a gliding reptile, mortar) it will transmute a wild swipe into brate, fused firmly to the bone of the jaws Kuehneosaurus; the early crocodilian a light and precise blow. But the excess (Fig. 2). The teeth and jaw bones of adult Terrestrisuchus\ the dinosaur Thecodon­ momentum, returned to the user's arm as specimens of Clevosaurus show signs of tosaurus'; the very early mammal an unexpected 'kick', warns him that his heavy wear, and the jaw action was a Kuehneotherium"; various unidentified blow was too heavy. His next swipe will not shearing one, rather like the action of a archosaurs'; and up to ten species of be so wild. Soon he will have a sound intui­ well-adjusted pair of scissors. Clevosaurus sphenodontid'·"-'". The Jurassic fissures tive feeling for the exact use of the hammer probably fed on hard-skinned inverte­ contain a rather different fauna, consisting in this task. Professionals and amateurs brates such as centipedes, insects and of the mammal Eozostrodon, the alike will welcome the electronic hammer: tritylodont Oligokyphus, the lepidosaur in all fields of engineering and domestic Gephyrosaurus and fish teeth'. construction it will teach the subtle kinetic The sphenodontids, such as Clevosaurus intuition of the true craftsman. Indeed, and its kin from the fissures, are of great electronically controlled impact may phylogenetic importance. They are become the preferred way of carrying out broadly similar to the living tuatara all sorts of tasks now conducted manually, Sphenodon from New Zealand, a so­ from removing a stopper to advancing a called living fossil. The fact that a complex pawn or shaping a cake. Daedalus is devis­ fauna of up to ten sphenodontids co­ ing a 'personal electronic hammer' to fit in existed in the south-west of Britain 220-- the pocket like a pen. The user will turn to 210 million years ago suggests that the it for any manual task as automatically as group was once as flourishing as the lizards he reaches for a pen to write with, or a are today'". D calculator to do arithmetic. I. Fraser, N.C. Phil. Trans. R. Soc. B321, 125-178(1988). But the best strategy for developing a 2. Swinton, W.E. Ann. Mag. nat. Hist. 4, 591-594 (1939). new invention is to launch a high-value 3. Benton, M.J. Nature 307, 111-112 (1984). 4. Crush, P.J. Palaeontology 21, 131-157 (1984). product first, on whose profits the mass 5. Kesmack, D. Zoo/.}. Linn. Soc. 82, 101-117 (1984). market can be attacked. So Daedalus's first 6. Fraser. N.C .. Wa1kden. G.M. & Stewart, V. Nature 314, 161-163 (1985). commercial product will improve the most 7. Fraser. N.C. Palaeontology 31, 567-576 (1988). valuable impacts of them all - those of 8. Fraser, N.C. Mod. Ceo/. 10. 147-157 (1986). 9. Whiteside,D.L Phil. Trans. R. Soc. B312.379-430(1986). international golf. His electronic golf clubs, 10. Benton. M.J. Nature 323, 762 (1986). bringing calibrated exactitude to this most Fig. 2 Composite restoration of the mand­ Michael J. Benton is in the Department of obsessive and unforgiving of games, should ible of C. hudsoni in: a, dorsal; b, medial; c, sell for tens of thousands of pounds. lateral views. Scale bar, 1 em. (From ref. L) Geology, The Queen's University, Belfast BT7 iNN, Northern Ireland. David Jones