Mid-Cretaceous (Albian–Cenomanian) fossil woods from Hwawon-myeon in Jeollanam-do,Korea, and their palaeoclimatic implications

Two coniferous fossil wood taxa are reported from the Hwawon Formation (middle Cretaceous) at Hwawon-myeon in Jeollanam-do, Korea: Agathoxylon sp. and Taxodioxylon sp. Agathoxylon has a clear affinity with the Araucariaceae and its occurrence in the Hwawon Formation suggests that a dry and tropical–subtropical climate prevailed in this area during the middle Cretaceous. The presence of traumatic resin canals in the Taxodioxylon specimens indicates that flooding occurred repeatedly as part of an alternation between dry and rainy seasons. The low diversity observed for the Cretaceous fossil wood assemblages from the Korean Peninsula could be explained by the palaeoclimatologically stressful environment, as a dry tropical–subtropical climate prevailed over the region at that time.     

Fossil coniferous wood from the Early Cretaceous Jehol Biota in western Liaoning,NE China: New material and palaeoclimate implications

The Early Cretaceous Jehol Biota, one of the most important Mesozoic lagerstätten in East Asia, is especially well-known for occurrences of fossil feathered dinosaurs and early angiosperms. However, the terrestrial biodiversity, especially the fossil wood record, is poorly known. In this study, several structurally preserved coniferous wood specimens from the Lower Cretaceous Yixian Formation are investigated, based on collections from the Heichengzi Basin in Beipiao of western Liaoning, Northeast China. Four species referred to four genera of fossil wood are described, including Taxodioxylon heichengziense sp. nov., Thujoxylon beipiaoense sp. nov., Sciadopityoxylon liaoningense Ding and Protocedroxylon shengjinbeigouense sp. nov. These new records enlarge the fossil wood diversity of the Yixian Formation up to 10 species in 9 genera, and provide further insights into the forest vegetation composition of the Early Cretaceous Jehol Biota. Systematic analysis of the floral constitution indicates that the petrified forests of the Yixian Formation are dominated by conifers, represented by Araucariaceae, Podocarpaceae, Sciadopityaceae, Pinaceae and Cupressaceae in the western Liaoning region. Palaeoclimatical analysis of the fossil wood assemblage implies that the western Liaoning region was dominated by a cool temperate, wet and seasonal climate with variable interannual water supply in the western Liaoning region during the Early Cretaceous.     

Aptian–Albian Cupressaceae (sensu stricto) woods from Cañadón Asfalto Basin,Patagonia Argentina

This paper describes the first macrofloristic record from Los Adobes Formation (Chubut Group) in Cañadón Asfalto Basin (Patagonia, Chubut Province, Argentina). The studied fossils were recovered from the Aptian–Albian Bardas Coloradas Member, and consist of silicified woods preserved in fluvial channel deposits. One wood shows homocellular rays with smooth radial and tangential walls, diffuse axial parenchyma, tracheid pitting of the abietinoid type and cross-field pitting cupressoid usually ordered in rows and columns indicating placement within Cupressinoxylon hallei Kräusel. This fossil tree resembles some members of the extant Cupressaceae s.s., as Austrocedrus chilensis (D. Don) Pic. Serm. & Bizzarri, Pilgerodendron uviferum (D. Don) Florin, Fitzroya cupressoide (Molina) I. M. Johnst. and Libocedrus plumosa (D. Don) Druce. Due to poor preservation the other fossil wood specimen was assigned to cf. Cupressinoxylon Göppert 1850 nom. cons. prop. This is the first unequivocal record of C. hallei from the Cretaceous of South America and the oldest reliable record of the Callitroideae, indicating that this subfamily was well established since the mid-Cretaceous in the Southern Hemisphere.     

内蒙古发现白垩纪大型拟苏铁科(本内苏铁目)茎干化石

内蒙古包头达尔罕茂明安联合旗发现了保存完整的白垩纪大型本内苏铁目拟苏铁科拟苏铁属(Cycadeoidea)茎干化石。茎干化石呈椭球形,保存完好,高56cm,最大直径48cm,化石表面密布的菱形叶柄基呈螺旋状排列,从基部至顶端叶柄基逐渐变小,球果不均匀散生于叶柄基之间。茎干化石从内到外包括中央的髓部、外围的木质部圆筒、叶柄基、球果等。这是国内首次发现保存比较完整的本内苏铁目拟苏铁科茎干化石。同时,在茎干化石产地附近还发现有裸子植物宽孔异木(Xenoxylon latiporosum(Cramer)Gothan)木化石。本内苏铁茎干及宽孔异木化石对于研究本内苏铁目的演化历史和当时的植物群组成特点具有重要的科学意义。     

Conifer fossil woods from the Santa Marta Formation (Upper Cretaceous), Brandy Bay,James Ross Island,Antarctica

Conifer fossil woods from the Santonian to lower Campanian Santa Marta Formation are anatomically studied in detail. The wood flora is dominated by conifers, mainly Araucariaceae. Conifer fossil woods represent 84% of the samples (26 of 31) of the assemblage. The remaining samples are dicotyledon woods which are not included in this study. Woods are mostly calcified and preservation is often excellent. Fossil woods include three species of Agathoxylon, Phyllocladoxylon antarcticum, Cupressinoxylon hallei and a new species of Cupressinoxylon, C. rotundum Pujana sp. nov. The conifer-dominated forests are consistent with the pollen and macrofloras previously described from sediments of the same stratigraphic unit. This fossil wood assemblage contributes to understand the floristic changes that took place in the Cretaceous forests.     

Termite borings in Early Cretaceous fossil wood, Isle of Wight, UK

A pellet-filled boring in fossil wood is described from the Early Cretaceous Wessex Formation (Barremian), Isle of Wight. The cylindrical boring, approximately 1 cm in diameter, is filled with carbonaceous pellets with a hexagonal shape, preserved within a matrix of pyrite. Features of the boring suggest that it was made by termites that bored into the wood, either when the tree was alive or in the early stages of decay on the forest floor. This evidence of termite activity complements previous records of termite wing fossils and faecal pellets in Wealden sediments and is evidence for social behaviour in Wealden insects. This is one of the oldest records of termite borings in wood.     

New fossil anurans from the Lower Cretaceous Sasayama Group of Hyogo Prefecture,Western Honshu,Japan

We describe two well-preserved and articulated fossil anurans excavated from the Lower Cretaceous Sasayama Group in Hyogo Prefecture, Western Honshu, Japan, as new taxa on the basis of unique combinations of character states. We performed a phylogenetic analysis that included these new taxa, as well as Mesozoic and archaic anurans. This analysis strongly supports the monophyly of each of the two new taxa, both of which are placed in more derived positions than extant leiopelmatids or Liaobatrachus from the Lower Cretaceous in China. Anuran specimens from the Tetori Group of Japan are not assigned to the two new taxa, suggesting that at least three anuran taxa were present in Japan during the Early Cretaceous. These Japanese representatives are not closely related to known fossil anurans from Eastern Eurasia, unlike recently described Cretaceous lizards from these two regions.     

Knoblochia cretacea,Late Cretaceous insect eggs from Central Europe

The genus Knoblochia is established for fossil insect eggs. The fossils are small, longitudinally ridged, ovoid to round with projections on both ends. Their thin perforated wall is covered by minute papillae, inner surface of the wall is smooth or covered by rectangular files of cells. Fossils assigned here to Knoblochia cretacea were earlier assigned to the genus Spirellea, which encompass a heterogenous complex of small fossils being or resembling angiosperm seeds from the Late Cretaceous. The majority of species of the genus Spirellea clearly represents remains of angiosperms. However, fossils described by Knobloch and Mai (1986) as Spirellea kvacekii are distinct, particularly in having external walls perforated, neither apex nor basal projection showing any absition scar or micropyle in the botanical sense. Attribution of these fossils to insects led us to designate the new name Knoblochia cretacea with a new holotype for fossils of this kind. Comparison of Knoblochia with insect eggs of species of Phasmatodea and Lepidoptera, and seeds of Stemonaceae showed clear affinity to insects. Due to the high amount of extinction among insects since the Cretaceous, the systematic affinity of Knoblochia remains open.     

A new hangingfly (Insecta,Mecoptera, Bittacidae) from the Purbeck Limestone Group (Lower Cretaceous) of southern England and a review of Cretaceous Bittacidae

Rapid radiation of the Bittacidae during the Jurassic resulted in high diversity within this family of Mecoptera. More than 40 species within 23 genera have been described from this period. However, around the end of the Jurassic the abundance and diversity of Bittacidae decreased and only seven species in five genera are known to date from the Cretaceous. A new specimen from the basal Cretaceous of England, Tytthobittacus jarzembowski sp. nov., described here, represents the eighth species and the second fossil representative of this family from the European Cretaceous. This hangingfly belongs to an extant and relictual genus previously known only from Australia. The paper also includes a review of all known Cretaceous bittacids and a re-examination of European species Antiquanabittacus nanus Petrulevičius and Jarzembowski, 2004.     

Preservation of borings: contrasting examples from the type Maastrichtian (Upper Cretaceous), southern Limburg,the Netherlands

The taphonomy of trace fossils and their substrates remains an understudied facet of sedimentary geology. Contrary to common prejudice, trace fossils are not invariably preserved in situ, but may be exhumed and reworked following lithification. The trace fossils most commonly found ex situ are borings in mobile shelly substrates. Two notable, but contrasting, examples of post-mortem transport of borings are described from the Maastrichtian (Upper Cretaceous) of southern Limburg, the Netherlands. A long, unusually straight and complete calcareous tube assigned to Teredolites longissimus Kelly and Bromley is an organically secreted internal mould, produced by a teredinid or pholadid bivalve boring in wood and lining their tube. Strictly, this is part of the body fossil of the producing bivalve, but it is also an organically generated internal mould of the boring. A flint steinkern of a right valve of Crassatella bosquetiana d’Orbigny preserves a suite of silicified borings. Caulostrepsis taeniola Clarke is a U-shaped boring with a vane connecting the parallel limbs. Talpina isp. is a slender, simple, branched tunnel. Most unexpected, Spirichnus spiralis Fürsich et al. is a spiral ‘worm’ boring hitherto only known from the Upper Jurassic. This stratigraphic gap is likely an artefact; only mouldic preservation of the bored substrate would expose the distinctive Spirichnus boring. These ichnofossils are united in their occurrence in unusual preservational systems.     

Fire in a Weichselia-dominated coastal ecosystem from the Lower Cretaceous (Barremian) of the Kurnub Group in NW Jordan

Large intervals of the Cretaceous are considered as a ‘high-fire’ period in Earth's history. However, so far most studies dealing in greater detail with the fossil evidence of palaeo-wildfires, i.e. fossil charcoal, originate from the northern hemisphere (i.e. North America, Europe, Asia) whereas there are large stratigraphic and geographic gaps on the Cretaceous southern continents. The present paper deals with the fossil contents (plant macro-remains, palynomorphs and charcoal) of a lignite lens from the lower part of the Lower Cretaceous Kurnub Group near King Talal Dam in Jordan. The data provide evidence for the repeated occurrence of palaeo-wildfires in coastal ecosystems on the northern margin of Gondwana during the Barremian. The fossil content of the lens indicates that the vegetation, which was repeatedly affected by fire, has been dominated by the matoniaceous tree fern Weichselia reticulata. Palynological data from the lignite, as well as the repeated occurrence of wildfires point to an at least seasonally dry (or at least less humid) climate during deposition of the lignite.     

Strontium isotope age-dating of fossil shark tooth enameloid from the Upper Cretaceous Strata of Alabama and Mississippi,USA

Cretaceous strata in Alabama and Mississippi (USA) represent one of the most complete records of shallow marine deposition worldwide for the Upper Cretaceous. The age assignment of these strata in the eastern Gulf Coastal Plain is difficult due to the comparative lack of radiometrically datable beds and sometimes conflicting results of biostratigraphy using different taxonomic groups. Numerical age dating using strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) preserved in diagenetically resistant fossil shark tooth enameloid had been proposed by previous researchers as a solution to dating some geologic units. Here we apply this methodology to the whole Upper Cretaceous, using teeth of two fossil shark genera (Scapanorhynchus and Squalicorax) collected from variable facies. Shark teeth collected from a bentonite mine in Monroe County, Mississippi, were also analyzed and compared with the radiometric date of the bentonite layer. Results indicate a strong correlation between stratigraphic position of the fossil teeth and numerical age determination based on ⁸⁷Sr/⁸⁶Sr content. Furthermore, this method is equally effective for both of the fossil shark genera analyzed in the study. Because of the nearly uniform distribution of strontium in ocean water, numerical age dating using strontium isotope ratios preserved in fossil shark tooth enameloid can be a useful method to employ in the correlation of marine geological strata on both regional and global scales.     

Notes on the divergence time of the fern genus Asplenium from fossil and molecular evidence

The extant fern genus Asplenium Linnaeus, 1753 is widely distributed in tropical-temperate regions and shows a high diversity. The oldest fossils assigned to it comprise fronds and spores preserved in situ from the Lower Cretaceous of northeast Asia. However, molecular dating suggests that Asplenium diverged during the Paleocene (∼57.7 Ma). Here we present some explanations for the disparity in fossil and molecular age estimates, and new insights into the origin and evolution of the genus. We suggest that Cretaceous Asplenium most likely represents a stem-group member, and that lineage extinction during the early evolutionary stages of the genus resulted in missing nodes.     

Upper Maastrichtian shallow marine environments and neoselachian assemblages in North Iberian palaeomargin (Castilian Ramp,Spain)

Upper Maastrichtian deposits formed in a nearshore subtidal environment within the Valdenoceda Formation (Castilian Ramp, North Iberian margin) are described together with two recently found selachian assemblages. Rare earth element concentrations (REE) have been used to assess the degree of taphonomic mixing and reworking, observing that it is minor or non-existent, and differences in degree of preservation and ecologic mixing can be explained by biostratinomic processes. The patterns of REE also helped to obtain a better understanding of the depositional environment, including the diagenetic history from burial to final degree of bone preservation.The fossil assemblages here described are close to that of the late Maastrichtian of Albaina (in the enclave of Condado de Treviño, Burgos), both in the Basque-Cantabrian Region, but their age may be slightly older (early late Maastrichtian). In total, the new assemblages consist of 17 taxa, assigned to 11 genera of shallow-water dwellers combined with individuals from the outer shelf. They represent cosmopolitan taxa (Squalicorax pristodontus, Serratolamna serrata and Rhombodus binkhorsti) together with local species (Rhinobatos echavei, Rhinobatos ibericus). Although there are not significant differences between Albaina and Quintanilla la Ojada faunas, the new assemblages add interesting taphonomic and geochemical information to the few existing uppermost Cretaceous deposits with fossil sharks in southwestern Europe.     

The first fossil of dasycerine rove beetle (Coleoptera: Staphylinidae) from Upper Cretaceous Burmese amber: Phylogenetic implications for the omaliine group subfamilies

The enigmatic staphylinid subfamily Dasycerinae consists of only 17 species within a single extant genus Dasycerus, but it is easily distinguished from other rove beetles by overall, latridiid beetle-like body and extremely slender, verticillate antennae. Direct fossil evidence is lacking for this group. Here, I describe the first fossil of this peculiar subfamily, Protodasycerus aenigmaticus gen. and sp. n., from the Upper Cretaceous Burmese amber. Despite considerable external similarities to extant dasycerine species, this new genus possesses several important morphological differences: a much smaller body size (ca. 1.1 mm), narrowly elongate antennomeres 1 and 2, not strongly transverse metaventrite, elytra striate but not tricostate, and truncate posterior margin of the elytra exposing four abdominal tergites dorsally. The new finding of a Cretaceous representative of the Dasycerinae helps elucidate the origin and early evolution of the omaliine group subfamilies, implying rather close similarities between the Dasycerinae and the monobasic subfamily Neophoninae. Discovery of P. aenigmaticus suggests a rather ancient origin of the subfamily by the Upper Cretaceous.     

A new genus and species of soldier beetle from Upper Cretaceous Burmese amber (Coleoptera,Cantharidae, Malthininae)

A new Upper Cretaceous genus and species of soldier beetles, Archaeomalthodes rosetta gen. et sp. nov., is described and illustrated from an individual preserved in Upper Cretaceous (Cenomanian, ca. 99 Ma) amber from northern Myanmar. It is undoubtedly placed in extant subfamily Malthininae based on its small-sized body, somewhat abbreviated elytra and fusiform terminal maxillary palpomere, representing the oldest documented occurrence of Malthininae. It suggests that this subfamily is an ancient group, which originated at least in the earliest Late Cretaceous. Our discovery sheds light on the palaeodiversity of Cantharidae in the Late Mesozoic. Together with other previously reported fossil cantharids, it is likely that Malthininae has been fairly diverse during the early evolution of Cantharidae. On the other hand, a morphological similarity between Archaeomalthodes and Recent malthinines and the occurrence of flowering plants in the Burmese amber implies a potential flower-visiting behaviour of this fossil species.     

A new Late Cretaceous genus and species of polypore fungus beetles (Coleoptera,Tetratomidae) from northern Myanmar

A new polypore fungus beetle is described and illustrated, under the name of Thescelostrophus cretaceus gen. et sp. nov., representing the first documented occurrence of the tribe Eustrophini. The well-preserved specimen was collected from the Upper Cretaceous (Cenomanian, ca. 99 Ma) amber near the Hukawng Valley of northern Myanmar. This fossil species can be assigned to the extant subfamily Eustrophinae based on its elongate oval and strongly narrowed posteriorly body, simple and narrow tarsi, and somewhat clubbed antennomeres. The comparison among the extinct and extant eustrophines supports the previous hypothesis that antennal morphology of early eustrophines was very diverse. Additionally, an overall similarity between Thescelostrophus and extant eustrophines suggests a potential fungivory of this fossil species. Morphological characters preserved in the Burmese amber highlight the diversity of tetratomids during the Late Mesozoic and provide data for future phylogenetic studies of Tetratomidae.