Vol 50, No 1 (2016)

Reconstruction and new description of the rare species Charniodiscus yorgensis Borchvardt et Nessov, 1999, which has previously been represented by a single, presently lost specimen, is provided. New material collected in the type locality and closely situated outcrops of Zimnii Bereg of the White Sea allows reconstruction of the structure of this fossil form in more detail. Like other species of the genus Charniodiscus Ford, 1958, the specimen of C. yorgensis, replaced by pyrite initially nonmineralized skeleton of an organism, consisted of a bilobate frond with the rachis passing downwards into the basal disk. It is shown that each lobe of the frond of C. yorgensis was an entire membrane arranged in transverse folds, as an accordion. Plicate lateral lobes, with their free margins directed upwards, adjoin sharp ridges of folds on either side of the membrane. Semipouches formed of bends of lateral lobes were probably the bases of tubular or seedlike elements of branches of the second order, recognized in C. oppositus Jenkins et Gehling, 1978 and C. arboreus (Glaessner, 1959) from Australian localities. Unique records of C. yorgensis buried in an upstanding position corroborate the well-known hypothesis of the vertical lifetime orientation of Charniodiscus.

A new species, Milax vitukhini sp. nov., from the newly recognized Kimmeridgian–Tithonian radiolarian association from volcanogenic–siliceous–terrigenous rocks of the Borozda Creek Basin (Ust’-Belsky Mountains, Koryak Upland) is described.

New strophomenid and rhynchonellid (Brachiopoda) taxa are described from the Lower Pragian (Soda Creek Limestone) of west-central Alaska: Harperoides gen. nov. with type species H. alaskensis sp. nov. (subfamily Mesodouvillinae Harper et Boucot) and Pedderia gen. nov. with type species P. fragosa sp. nov. (family Pygmaellidae Baranov).

The revision of the type collections on the genus Pseudorhaptagnostus Lermontova, 1940 has shown the validity of the type species. Originally indicated type species P. simplex Lermontova, 1951 appeared to be erroneously combination of cephala and pygidia from different species; recombined set of cephala and pygidia for P. simplex synonymized it with P. punctatus Lermontova, 1940, and therefore renamed the type species as the latter one. Also Pseudorhaptagnostus has shown to differ from its close morphological affinities Neoagnostus, Norilagnostus, Machairagnostus, Idolagnostus. New introduction of their morphological difference allowed us to rearrange the species assignment of these genera.

The new genus and new species of seed beetles (Copeoptera, Chrysomelidae, Bruchinae) Electrocaryedon poinari gen. et sp. nov. are described from the Late Eocene Baltic amber. This new genus differs from the genus Caryedon Schoenherr, 1823 in the completely separate procoxal cavities, not shortened lateral carina on pronotum, and wider body with sparse setae.

A new conifer species, Sequoiadendron tchucoticum A. Sokolova from the Emuneret Formation on the Enmyvaam River (Anadyr River Basin) is described. It is established based on a thorough study of the morphology and epidermal features of shoot impressions, using scanning electron microscopy. The new species has polymorphic shoots with helical branching and three main leaf types: scalelike, subulate, and falcate. Leaves are amphistomatic; amphicyclic stomata are mostly obliquely arranged; ordinary epidermal cells are rectangular, frequently with oblique end walls, and their length-to-width ratio reaches 15: 1. Shoots of the new species prevail among conifers of the Ust’-Emuneret Assemblage. The age of the deposits enclosing the assemblage is debated; according to the latest data, it is estimated as Santonian–Early Campanian.