New data on mollusks from the Miocene (Tarkhanian-Chokrakian) of northern Sinop Province,Turkey

An insufficiently known bivalve and gastropod assemblage from the Early-Middle Miocene (Tarkhanian-Chokrakian) of northern Sinop Province (Turkey), is analyzed. Environments of the assemblage are reconstructed for the Chokrakian as subtidal, with prevailing lime and sandy bottom and good aeration, and partially well vegetated. Impoverishment of the mollusk biocoenose in this part of the marine basin (only 18 bivalve and 22 gastropod species recorded) compared to other areas, including the closest regions, Bulgaria on the west and Georgia on the east, is emphasized. The relatively low diversity of the fauna is probably connected not only with insufficient collecting, but with special hydrological conditions. A special aspect of the fauna is highlighted by the presence of the bivalve Circomphalus foliaceolamellosus subplicatus (Orb.), which is rare in the Chokrakian.     

Comparative floral development of Mir-grown and ethylene-treated,earth-grown Super Dwarf wheat

To study plant growth in microgravity, we grew Super Dwarf wheat (Triticum aestivum L.) in the Svet growth chamber onboard the orbiting Russian space station, Mir, and in identical ground control units at the Institute of BioMedical Problems in Moscow, Russia. Seedling emergence was 56% and 73% in the two root-module compartments on Mir and 75% and 90% on earth. Growth was vigorous (produced ca. 1 kg dry mass), and individual plants produced 5 to 8 tillers on Mir compared with 3 to 5 on earth-grown controls. Upon harvest in space and return to earth, however, all inflorescences of the flight-grown plants were sterile. To ascertain if Super Dwarf wheat responded to the 1.1 to 1.7 micromoles mol-1 atmospheric levels of ethylene measured on the Mir prior to and during flowering, plants on earth were exposed to 0, 1, 3, 10, and 20 micromoles mol-1 of ethylene gas and 1200 micromoles mol-1 CO2 from 7 d after emergence to maturity. As in our Mir wheat, plant height, awn length, and the flag leaf were significantly shorter in the ethylene-exposed plants than in controls; inflorescences also exhibited 100% sterility. Scanning-electron-microscopic (SEM) examination of florets from Mir-grown and ethylene-treated, earth-grown plants showed that development ceased prior to anthesis, and the anthers did not dehisce. Laser scanning confocal microscopic (LSCM) examination of pollen grains from Mir and ethylene-treated plants on earth exhibited zero, one, and occasionally two, but rarely three nuclei; pollen produced in the absence of ethylene was always trinucleate, the normal condition. The scarcity of trinucleate pollen, abrupt cessation of floret development prior to anthesis, and excess tillering in wheat plants on Mir and in ethylene-containing atmospheres on earth build a strong case for the ethylene on Mir as the agent for the induced male sterility and other symptoms, rather than microgravity.     

Iraida Pavlovna Morozova (1919–2007)

Paleontological Journal -     

A new subgenus and a new species of the tenebrionid genus <Emphasis Type="Italic">Leptodes</Emphasis> Dejean, 1834 (Coleoptera,Tenebrionidae)

The genus Leptodes was erected by Dejean (1834) for a single species, Sepidium boisduvalii Zubkoff, 1833, which is, consequently, the type species by monotypy. Kaszab (1959) established in Leptodes the subgenus Leptodinopsis based on the same type species, Sepidium boisduvalii. Thus the names Leptodes and Leptodinopsis are objective synonyms: Leptodes Dejean, 1834 = Leptodinopsis Kaszab, 1959, syn. n. A new subgenus Mesoleptodes G. Medvedev et Iljina subgen, n. (type species Leptodes semenowi Reitter, 1892) is established for species which Kaszab included in Leptodes s. str. A new species, Leptodes daghestanicus G. Medvedev et Iljina, sp. n., is described from Daghestan.     

Morphogenesis of rissoidae in the inland basins of the Eastern Paratethys

Miocene rissoids from the heterochronous low-salinity seas of the Eastern Paratethys (Early Chokrakian, Karaganian, Late Konkian, Early Sarmatian, and Early Maeotian) were revised. The polyphyletic genus Mohrensternia is subdivided into several generic and subgeneric taxa. The new genus Zhgentia and the new subgenera Rissoa (Turboellina), R. (Pseudoturboellina), and R. (Maeotia) are established.     

Shell morphology and microstructure of Neogene <Emphasis Type="Italic">Melanopsis</Emphasis> Ferussac (Gastropoda)

Representatives of the genus Melanopsis have an extraconch, a shell structure unusual for gastropods, which envelops several whorls, including the last whorl and up to two preceding whorls. Microstructural features of the shell are studied for the first time, using M. impressa Krauss as an example. It is shown that the extraconch is formed by the outer crossed-lamellar layer.