Review of the ammonite genus Pseudokossmaticeras Spath, 1922 from the uppermost Campanian–lower Maastrichtian in Bulgaria

New data on the ammonite genus Pseudokossmaticeras Spath, 1922 have been obtained from several uppermost Campanian–lower Maastrichtian strata of the Fore-Balkan Mountains (Bulgaria). A review of the earlier Bulgarian records of the genus is also presented. The following species are here described and illustrated: Pseudokossmaticeras brandti (Redtenbacher, 1873), P. galicianum (Favre, 1869), P. muratovi Michailov, 1951 and P. tercense (Seunes, 1892). Our newly obtained ammonite records were constrained by the inoceramid zonation that has recently been proposed for successions of the Fore-Balkan area. Hence, the Bulgarian data are of importance for correlation with other occurrences of Pseudokossmaticeras across Europe

First record of an erymid lobster (Crustacea, Decapoda) from the upper Bajocian of Northwest Bulgaria

Fossil chela of an erymid lobster from a single locality of the upper Bajocian in the Western Fore-Balkan Mts (NW Bulgaria) was studied. Two segments of the thoracic appendages, probably belonging to one individual, were described: 1) P1 propodus with partially preserved pollex and dactylus; and 2) P1 carpus and P1 merus attached. These elements of the first pair of pereiopods of a lobster were identified as Eryma compressum (Eudes-Deslongchamps, 1842). Eryma compressum is a well-known taxon from numerous Jurassic localities in Europe but has not been recorded in Bulgaria to date. Therefore, albeit being an isolated finding with only a few elements, the Bulgarian example contributes to the overall record of European erymid faunas from the Middle Jurassic, and especially in Eastern Europe, from where only a few erymids have been reported

Integrated biostratigraphy and palaeoenvironments of the Upper Cretaceous in the Petrich section (Central Srednogorie Zone, Bulgaria)

The Upper Cretaceous succession (Coniacian to lowermost Maastrichtian, with focus on the Campanian) at Petrich, Central Srednogorie Zone in Bulgaria, is described and calibrated stratigraphically based on nannofossils, dinoflagellate cysts and inoceramids. The following standard nannofossil zones and subzones are identified: UC10-UC11ab (middle to upper Coniacian), UC11c-UC12-UC13 (uppermost Coniacian to Santonian), UC14a (lowermost Campanian), UC14bTP-UC15cTP (lower Campanian to ‘middle’ Campanian), UC15dTP-UC15eTP (upper Campanian), UC16aTP (of Thibault et al. 2016; upper part of the upper Campanian), and UC16b (Campanian-Maastrichtian boundary). The base of the Campanian is defined by the FO of Broinsonia parca parca (Stradner) Bukry, 1969 and Calculites obscurus (Deflandre) Prins and Sissingh in Sissingh, 1977 (a morphotype with a wide central longitudinal suture). The Areoligera coronata dinoflagellate cyst Zone (upper lower Campanian to upper upper Campanian) is identified, corresponding to the UC14bTP-UC16aTP nannofossil subzones. The inoceramid assemblage indicates the ‘Inoceramus’ azerbaydjanensis-‘Inoceramus’ vorhelmensis Zone, correlated within the interval of nannofossil subzones UC15dTP-UC15eTP. The composition of the dinoflagellate cyst assemblages and palynofacies pattern suggest normal marine, oxic conditions and low nutrient availability within a distal shelf to open marine depositional environment during the Campanian

Inoceramid bivalve and dinoflagellate cyst integrated biostratigraphy of the topmost Campanian–Maastrichtian in a part of the Western Fore-Balkan Mountains, northwest Bulgaria

We present the inoceramid and dinoflagellate cyst record from the topmost Campanian–Maastrichtian strata of three key sections of the Western Fore-Balkan Mountains, northwest Bulgaria. The following inoceramid zones were recognized: “Inoceramus” redbirdensis Zone, Endocostea typica Zone, Trochoceramus radiosus Zone and “Inoceramus” ianjonaensis Zone. The Campanian/Maastrichtian boundary was tentatively drawn slightly below the first occurrence of Endocostea typica. The uppermost inoceramid assemblage was confined to the lower part of the upper Maastrichtian. Dinoflagellate cyst ranges, as well as the first and the last occurrence events of dinocysts, provided valuable markers for the stratigraphic subdivision of the Maastrichtian. The first occurrence of Microdinium carpentierae was documented in proximity to the Campanian/Maastrichtian boundary. The Cerodinium diebelii Zone was recognized with a stratigraphical range from the lower Maastrichtian to the lower upper Maastrichtian. The last occurrence of Alterbidinium acutulum was recorded in the lower Maastrichtian and used as aid for tracing the lower/upper Maastrichtian substage boundary. The marked domination of delicate chorate dinocysts in all sections and the encountered low P/G ratio values are indicative of stable low-energy depositional environment and oligotrophic conditions, with normal marine productivity and nutrient availability in the basin during the Maastrichtian

Palynostratigraphy of dinosaur bone-bearing deposits from the Upper Cretaceous of Western Bulgaria

Palynological investigation of the Vrabchov dol locality (Western Bulgaria) which recently yielded fragmentary dinosaur bones attributed to the clade Titanosauria, reveals well-preserved sporomorph assemblages dominated by angiosperm pollen from the Normapolles group, spores and rare gymnosperms. The age assessment of the studied sequence is based on the diagnostic Normapolles species, such as Oculopollis orbicularis Góczán, 1964, Oculopollis zaklinskaiae Góczán, 1964, Krutzschipollis spatiosus Góczán in Góczán et al., 1967 and Krutzschipollis crassus (Góczán, 1964) Góczán in Góczán et al., 1967. The concurrent presence of these pollen species suggests a late Santonian–early Campanian age for the succession. The sporomorph association is encountered in a palynofacies dominated by continental elements, including translucent phytoclasts (tissues, wood remains and plant cuticles). The sedimentary succession shows no evidence of marine elements and a very low proportion of AOM that attests to deposition within a lagoonal to foreshore marine environment, with high continental input and short transportation. The vegetation in the studied area was primarily composed of a range of Normapolles-producing angiosperms and secondarily of pteridophyte spore-producing plants. Gymnosperms were rare. Such a vegetation pattern reflects a warm, seasonally dry climate during the late Santonian–earliest Campanian in the studied area. The dinosaurs inhabited a wet lowland area, probably rich in herbaceous plants

Identification of fungal taxa with pathogenic potential in soil samples from Perunika Glacier’s newly formed forefields - Livingston Island, Antarctica

Antarctica peninsula periphery islands undergo one of the most dramatic ecological changes due to ongoing global warming. The front fields of the Antarctic glaciers are extreme environments and pioneering sites for ecological succession. Rising temperatures lead to deglaciation in the Antarctic habitats, and the new terrain is subjected to the process of soil formation and microbial colonization. In the present study, we investigated the formation of pathogenic fungal soil microbiomes as an effect of forefield deglaciation. Soil samples were taken from two different forefields, one formed several years ago and the other freshly uncovered. Both habitats were in the vicinity of the Perunika Glacier situated in the northeastern direction of Hurd Peninsula, Livingston Island, the second largest island from the South Shetland Archipelago, about 100 km north of the Antarctic Peninsula. Total DNA was extracted and targeted ITS amplicon sequencing was applied. The ITS marker sequences were then taxonomically identified. The abundance of the fungal taxa was calculated. Alpha and Beta diversity analyses to obtain fungal richness in samples were performed. Our results showed that soil habitat formation, initiated by deglaciation, was such that:In the newly deglaciated forefield, there was almost no fungal DNA, which prevented further analysis; At older drier fields metagenome content was much higher; Further analysis showed that the most abundant genera were Pseudogymnoascus, Simplicillium, Hanseniaspora, Mycothermus, and Malassezia.It is known that Pseudogymnoascus and Malassezia species have pathogenic keratinolytic activity. In conclusion, the phylum Ascomycota, which dominated the core microbiome showed much higher ecological diversity and abundance, i.e. potential for colonization of the glacier forefields. In contrast, the phylum Basidiomycota appeared to be less fit for these conditions