 of this paper prefers the molecular clock hypothesis over evidence from the fossil record, and concludes that molecular differences indicate that mammal orders arose at different times, but the fossil record is too incomplete to indicate the order in which they arose.
MOLECULAR PHYLOGENY OF PLANT FAMILIES?
Archie JW. 1989. Phylogenies of plant families: a demonstration of phylogenetic randomness in DNA sequence data derived from proteins. Evolution 43:1796-1800.
Summary. Archie examines the results of a study of phylogenetic relationships among nine plant families based on a set of DNA sequences derived from protein sequences for three proteins. Archie concludes that the DNA sequences used do not contain phylogenetic information, and suggests procedures for identifying whether other such sequences are useful in studying phylogeny.
PALEOBIOGEOGRAPHY AND PLATE TECTONICS
Jaeger J-J, Courtillot V, Tapponnier P. 1989. Paleontological view of the ages of the Deccan traps, the Cretaceous/Tertiary boundary, and the India-Asia collision. Geology 17:316-319.
Summary. The Deccan traps are flood basalts covering a large area of India. Paleomagnetic dating indicates the volcanism that produced the Deccan traps occurred across the boundary separating the Cretaceous from the Tertiary. Fossils from below the basalts are similar to those found in beds among the lava flows, which is interpreted as evidence against rapid mass extinction. Similarities of fossils from beds among the lava flows and from Asian deposits are interpreted as evidence that the Indian plate collided with Asia much earlier than previously thought, probably close to the Cretaceous-Tertiary boundary. If so, the intra-continental shortening caused by the collision could be as much as 4000 km.
Briggs JC. 1989. The historic biogeography of India: isolation or contact? Systematic Zoology 38:322-332.
Summary. Maps showing continental movements typically show India located on the north side of Antarctica, between southeast Africa and western Australia, until about the Lower Jurassic. From this point, India is usually shown as traveling northward largely in isolation, finally colliding with the Asian continent during the lower Miocene sedimentation. The author shows that this scenario based on geophysical interpretations is not consistent with paleobiogeographical evidence. India does not show evidence of an endemic fauna or flora, but shows fossil similarities with other continents. The author supplies maps showing his interpretation of the evidence as indicating India made contact with Asia during Eocene sedimentation.
Comment.The conflict between interpretations based on geophysical vs paleobiogeographical evidence remains an unsolved problem for plate tectonic theory.
Smithson TR. 1989. The earliest known reptile. Nature 342:676-678.
Summary. A nearly complete, articulated skeleton of a four-legged reptile has been recovered from the black shale member of the East Kirkton Limestone in Scotland. The skeleton is about 8 inches in length. Classification has not yet been completed, but it is neither a synapsid nor a diapsid.
Comment. The fossil was discovered by a private collector, and controversy has arisen over the proposed sale of the fossil for nearly $350,000.
Mount JF. 1989. Re-evaluation of unconformities separating the “Ediacaran” and Cambrian systems, South Australia. Palaios 4:366-373.
Summary. The top of the proposed Ediacaran stratotype in the Flinders Ranges of South Australia was previously believed located at a regional unconformity. Reinterpretation suggests it is an abrupt facies change instead, and that the Ediacaran System stratotype may actually lie well within the Lower Cambrian.
RAPID CHANGE IN BIRDS
Diamond J, Pimm SL, Gilpin ME, LeCroy M. 1989. Rapid evolution of character displacement in myzomelid honeyeaters. American Naturalist 134:675-708.
Summary. A volcanic explosion, probably about four centuries ago, destroyed all life on Long Island, an island about 50 km off the northeastern coast of New Guinea. Long Island and two nearby islands have been 