Nl\ l'URE VOL .1.1.1 23 .JUNE l4~K 704 ·-·NEWS AND VIEWS will be possible to compute quantities such the square of/", and hence is reduced by a of vertebra. It joins the contro­ as /r from first principles in QCD. factor of about 3. versial Crassigyrinus from the Scottish One interesting implication of these The EMC measurements are the latest localities in showing that anthracosaur results concerns attempts to detect cold in a series of unexpected results in spin characters can co-exist in one with dark matter (J. Ellis, R.A. Flores and S. physics. They are perhaps simpler than extremely primitive features'. Ritz, CERN prcprint), essential to some the previous ones to interpret, in that they Clack1 gives an account of much earlier theories of cosmology. Among the candi­ involve the wavefunction of only one . The material was collected in dates for cold dark matter are the massive, proton. The results all indicate that our 1970 by Peter Friend and colleagues from weakly-interacting, neutral particles intuitive picture of the origin of the Cambridge while they were exploring the predicted in supcrsymmctric theories, in proton's spin, based on the non-relativis­ stratigraphic geology of the area in which particular the photino. It is hoped to tic quark model, is wrung. This leaves the lie the classic East Greenland Late detect these particles either directly in the following fundamental question: if the tetrapod sites (see figure). The laboratory, by observing their scattering quarks carry very little of the proton's commonest tetrapod from these sites is off matter, or indirectly by observing the spin, then what is the origin of the proton's /chthyostega, but Clack's new account is neutrinos which emerge when these parti­ spin? Docs it arise from the orbital angu­ of three closely associated skulls of cles annihilate in the Sun. Predictions of lar momenta of the proton's constituents Acanthos1ega, known previously from the detection rates for these particles will or from the spins of the gluons? D only two incomplete skull roofs. The new have to be revised because of the EMC specimens yield data on the braincase C. T. Sachrajda is in the Department of Physics, results. The rate for photino-proton Southampton University, Southampton 509 (typically tetrapod), lower jaw and scattering, for example, is proportional to 5NH, UK. shoulder girdle. Clack has just made a successful visit to East Greenland and Vertebrate palaeontology collected about three-quarters of a tonne of Devonian tetrapod specimens. The expedition on which Clack collec­ In search of earliest tetrapods ted her data'' was supported by the Green­ land Geological Survey. It was an Anglo­ Alec L. Panchen Danish initiative led by Svend Bendix­ Almgreen (Copenhagen), accompanied IN that period of the which Shale Group from which the earliest by Birger Jorgensen (Copenhagen), corresponds to the British Coal Measures, recorded Scottish tetrapods carne. Jenny and Rob Clack and Per Ahlberg there was enormous radiation of land One of the tetrapod fossils from Iowa is (Cambridge). The specimens collected vertebrates, tetrapods, which include the a member of the family Colosteidae, seem to be mostly Acanthostega, but earliest recorded and even the whose members are also known from the include lclzthyostega, which will supple­ earliest -like reptiles. But in the Edinburgh Oil Shales and above, from the ment data from specimens already in period of the Carboniferous before the later of West Virginia. and Stockholm/ The new material will be Coal Measures, roughly corresponding to the Mississippian of North America, and even more in the preceding Devonian period, tetrapod fossils come from very few localities, are rare as specimens and frequently poorly preserved. Two new papers add significantly to our knowledge of the anatomy and distribution of these earliest land vertebrates. On page 768 of this issue', Bolt and colleagues describe a new vertebrate locality from Iowa which contains many well-preserved fish and tetrapod fossils. This is the earliest pro­ ductive tetrapod site in continental North America. In the second paper', Clack adds to our knowledge of one of the two principal tetrapod genera from the Devonian of Greenland, preliminary to her successful visit to the localities. Uphill task- Stcnsiii Bjerg. Green! The new site described by Bolt et a!. is from the Coal Measures of Ohio'. The described in Cambridge and important important for three reasons - its early other principal tetrapod find represents a specimens then returned to Copenhagen. date, its geological location and the nature new taxon of very considerable interest. The material from East Greenland is the of its fossils. Before its discovery, tetrapods Bolt et a/. refer to it as a 'proto-anthraco­ only substantial collection of these earliest of Mississippian age were known from saur' and, rightly in my opinion, believe it land vertebrates. D three principal areas: the environs of to be closely related to, hut not a member l Bolt. J_R., t\1cKay. R.M .. Witzke. B.J. & McAdams. M.P Nawre 333. 76K- 770 ( Jl)t'~l- Edinburgh; Nova Scotia; and northern of, the Anthracosauria. The anthraco­ 2. Clotck. J _.\. Pa/m·mrrologr 31. 6lJ9-724 ( IYS8). West Virginia and the adjoining part of saurs arc a group of primitive tetrapods, J. t\tilncr. A.R. eta!. Mod. Geo!. 10, 1-2~ ( 1986). ranging in time from the Oil Shales to the 4 1-hmk. R.W. Am. ;\--/us. i\/m·il. 2770. 1---41 (1983) Pennsylvania'. There are Coal Measures "i P;mchcn. A.L Pl1if. Trans. R. Soc. 8309. 505--)6g (1985) sites in Illinois, but the Iowa find is the early and are thought by some to 6 Bcndix-Aimg:rccn. S.E.. Clack, J.A. & Olsen. H. Rapp. first Mississippian site to be reported from be closely related to (reptiles, GnMJ!(Ifu/s geol. Unders. 140, 95-102 (I Y88) 7 Janik. E. !Josie Strucrurc and E1·o!ution of Ver!ebrate.'l mid-continental North America and the and ). The proto-anthraco­ ( Al'ademic, London, Jl),S()) furthest west yet discovered. It is defi­ saur has some of the diagnostic features of Alec L. Panchen is Reader in Vertt'brate Zvul· nitely Lower Carboniferous in date, being the group, hut it is primitive in the config­ ogv in rhe Deparilll<'nl of Riulogv. University of of middle Visean age, and thus corres­ uration of the bones of the skull table and Newcastle upon Tvne. Newcastle Upon Tvne ponds to a horizon in the Edinburgh Oil in having possibly the most primitive type Nl:"l 7RU, UK.

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