A new Cenozoic cyclostome bryozoan genus from Argentina
and New Zealand: strengthening the biogeographical links
between South America and Australasia
PAUL D. TAYLO R and SOLE DAD BREZIN A
Uniserial encrusting cyclostome bryozoans (‘stomatoporiforms’) are especially challenging to study taxonomically because of the paucity of their
morphological characters. Here we introduce Axilosoecia gen. nov. for two previously undescribed species characterized by gonozooidal brood chambers located in the axils of branch bifurcations. The type species, Axilosoecia giselae sp. nov., comes from the upper, Danian part of the Roca Formation of La Pampa, Argentina; the second species, Axilosoecia mediorubiensis sp. nov., is from the lower Miocene of Southland, New Zealand. On account of its basal gonozooids, Axilosoecia is assigned to the family Oncousoeciidae despite similarities in colony form with Stomatoporidae. The two known occurrences of this new genus support previously suggested biogeographical links between southern South America and Australasia..
Keywords: Cyclostomata, taxonomy, Danian, Roca Formation, Miocene, Forest Hill Formation
A new Patagonian long-lived species of Cyclochlamys Finlay,
1926 (Bivalvia: Pectinoidea)
GUID O PASTORINO and MIGUEL GRIFFIN
A new species of the bivalve family Cyclochlamydidae is described from the southwestern Atlantic in Argentine waters. Cyclochlamys argentina
sp. nov. is the second representative of the genus known to live in the Magellanic area. In addition, this long-lived species is also recorded from
lower Miocene rocks in the province of Santa Cruz exposed along the Atlantic coast of the Monte León National Park. The material was collected
from the Punta Entrada Member of the Monte León Formation. These small mollusks clearly belong in Cyclochlamys because of shell characters
such as the irregularly pitted prodissoconch I and right valve with commarginally elongated rectangular prisms over most of disc. Cyclochlamys
argentina sp. nov. shows affinities with taxa such as C. aupouria and C. shepherdi, all of which are known from areas of New Zealand..
Key words: Cyclochlamydidae, southwestern Atlantic, Monte León Formation, Argentina.
A new Permian–Triassic boundary brachiopod fauna from
the Xinmin section, southwestern Guizhou, south China and
its extinction patterns
HUITIN G WU, WE IHONG HE, G.R. SHI, KEX IN ZHANG, TINGL U YANG , YANG ZHANG, YIFAN XIAO,
BING CHEN and SHUNBAO WU
A new brachiopod fauna comprising 31 species in 19 genera is described from a Permian–Triassic boundary section in Xinmin, Guizhou Province, Southwestern China. The brachiopods were collected from the Changhsingian (latest Permian) Changxing (=Changhsing) and Dalong (=Talung) formations and the lower Griesbachian (earliest Triassic) Daye Formation, which were deposited, respectively, in a shallow-water carbonate platform, upper offshore and carbonate platform settings. Among the brachiopods described and illustrated, a new species Juxathyris subcircularis is proposed. In addition, some species Araxathyris previously reported in south China have been discussed in detail and revised, with new morphological information. In particular, internal structures are provided for the first time for Orthothetina and Araxathyris species reported from south China. In addition, important clarifications are also provided on the morphology and diagnoses for Haydenoides, Martinia, Crurithyris and Transcaucasathyris, as well as for Paryphella transversa. Huiting Wu School of Earth Sciences, China University of Geosciences, Wuhan 430074, PR China and School of Life and Environmental Sciences,
Key words: Permian–Triassic boundary, Brachiopoda, taxonomy, Xinmin section, south China.
Bioerosion traces on titanosaurian sauropod bones from the
Upper Cretaceous Marília Formation of Brazil
VOLTAIRE DUT RA PAES NETO , HEITOR FRANCISCHINI , AGUSTÍN GUILLERMO MARTINELLI ,
THIAGO DA SILVA MARINHO , LUIZ CARLOS BORGES RIBEIRO, MARINA BENTO SOARES and
CESAR LEANDRO SCHULTZ
Bone bioerosions provide an important taphonomic record on fossils from continental deposits dating back to the late Paleozoic. The morphologicaldiversity of bone bioerosions is especially high in vertebrate remains from the Late Cretaceous. Here we describe four morphotypes of bioeroson preserved on titanosaur dinosaur bones collected from the Maastrichtian Marília Formation of Brazil. These traces differ from previously described ichnotaxa, and include branching furrows and surface removal resembling insect bioerosions, channels with semicircular cross-sections consistent with either root etchings or insects, and bite traces left by vertebrates. Taphonomic sequencing shows that time-averaging was an important aspect in the genesis of the Marília Formation taphocoenosis and demonstrates that traces left on bones are significant tools for reconstructing Late Cretaceous ecosystems.
Key words: root etching, insect borings, bite traces, Bauru Group, Dinosauria, ichnology, Cubiculum ichnofacies.
First record of Reduviasporonites from the Permian–Triassic
transition (Gondwana Supergroup) of India
RATAN KAR and AMIT K. GHO SH
We have performed a palynological study from an outcrop succession within the Gondwana Supergroup in India, spanning the end-Permian event. The sampled succession is located within the Tatapani-Ramkola Coalfield, in the Balrampur District of Chhattisgarh State, India. Diverse and wellpreserved palynological assemblages representing non-marine successions were identified and four assemblage zones were distinguished: the upper Permian Zone I: Striatopodocarpites–Densipollenites, and Zone II: Striatopodocarpites–Crescentipollenites; the Lower Triassic Zone III: Falcisporites–Klausipollenites and Zone IV: Densipollenites–Lunatisporites. Importantly, the fossil genus Reduviasporonites Wilson is recorded acros the Permian–Triassic transition in this study. Although the affinity of Reduviasporonites has been disputed (both fungal and algal affinities have been proposed), the genus is an important constituent of the palynological assemblages from the upper Permian and Lower Triassic deposits in different parts of the world. Here we report the first record of Reduviasporonites from the Permian–Triassic continental sediments in India, adding another significant data point for their presence at the Permian–Triassic boundary (PTB). We further discuss the affinity and palaeoecological perspectives of the taxon.
Key words: Reduviasporonites, Permian–Triassic Boundary, Tatapani-Ramkola Coalfield, Gondwana Supergroup, Peninsular India.
Foraminiferal biostratigraphy and facies analysis of the
Permian Longge Formation in the Rongma Area, Tibet,
China: implications for the palaeogeography of the South
Qiangtang Block
ZHONG -BAO WANG , JIN -HAN GAO, GEN -HOU WANG and ZHI-HONG KANG
The Permian Longge Formation in the South Qiangtang Block, Tibet, is overwhelmingly composed of carbonate rocks with various skeletal (brachiopods, foraminifers, gastropods, echinoderms, ostracods, corals, bivalves, algae, and bryozoans) and non-skeletal (intraclasts and ooids) components. Three stratigraphic sections of the Longge Formation in the Rongma area of north-central Tibet—known as South Yibug Caka, Niushan and East Yibug Caka—were selected for this study, which examined both sedimentary facies and foraminiferal assemblages. The foraminifers in these sections consist of at least 38 species belonging to 18 genera. Based on the distribution of the foraminifers throughout the composite section, two foraminiferal assemblages were established, and the age of the Longge Formation was determined to be late Kungurian to Capitanian. During lithological studies, ten microfacies were identified using depositional textures, petrographic analysis and faunal content: mudstone, bioclast wackestone, bioclast perforated-foraminifera packstone, bioclast crinoid grainstone, intraclast wackestone, breccia, intraclast grainstone, ooid grainstone, fine crystalline dolostone and residual-grain dolostone. These microfacies are interpreted to represent four depositional environments—restricted lagoon, open marine, shoal and slope—which together suggest a shoal-rimmed carbonate platform. The non-fusuline foraminifers show transitional palaeobiogeographic affinities (Tethyan Cimmerian subregion), and the assemblage is considered to be influenced by the northward drift of the South Qiangtang Block, the climatic warming after the Late Paleozoic Ice Age and warm-water oceanic currents caused by the newly formed Neotethys Ocean. This indicates that the South Qiangtang Block was located in a relatively warm-water, low-latitude area during the middle Permian. The Permian depositional sequences in the Rongma area were also influenced by the palaeogeographic evolution of the South Qiangtang Block.
Key words: foraminifers, microfacies, Longge Formation, Permian, South Qiangtang Block, Tibet
Fungal wood-decay strategies in Nothofagaceae woods from
Miocene deposits in southern Patagonia, Argentina
CARL OS DAN IEL GREPP I, JUAN L. GAR CÍA MAS SINI, ROBERTO R. PUJAN A and SERGIO A. MA RENSSI
Decayed woods from the Miocene, Rio Leona Formation, Santa Cruz, Argentina having simultaneous decay patterns consistent with soft- and
white rot characteristics are described. Samples were previously identifi ed as Nothofagoxylon scalariforme. At low magnification, the permineralized woods appear mottled, with discoloured, degraded areas, scattered in apparently robust tissue, consistent with white-rot decay. At greater magnification, the woods reveal several micromorphological features, including differential decay of cellulose-rich cellular components that match softrot decay by extant ascomycetes and some basidiomycetes. In addition, decayed woods either appear differentially delignified or show simultaneous decay of all cellular components (lignin- and cellulose-rich), which are by-products of white-rot fungal decay. Additional anatomical characteristic of the decayed woods are consistent with a host response to the fungal attack. Co-occurrence of these two decay patterns suggests soft-rot decay and white-rot fungal decay. In addition, co-occurrence of all the decay features observed also suggests facultative soft rot by white-rot fungi, such as in some extant species that switch between these two types of decay strategies as a means to circumvent plant defences. These data indicate that fungi with soft-rot capacity for wood decay can be traced back to the early Miocene (ca 19 Ma). In addition, this report adds to the distribution and diversity of fungi in the geological record and underscores the ecological importance of wood as a preferred substrate for the association and interactions between fungi with different saprotrophic abilities, which have been fundamental for nutrient recycling in terrestrial ecosystems during the Cenozoic..
Key words: white rot, soft rot, Nothofagoxylon scalariforme, secondary xylem, Río Leona Formation.
Middle–Upper Jurassic marine gastropods from central
Saudi Arabia
MARI EL FERRA RI, MAGDY EL-H EDENY , MOHAMED ZAKHERA, AHMED EL-SABBAGH and
SALEH AL FARRAJ
A total of 68 gastropod specimens are reported from the Middle‒Upper Jurassic sedimentary successions exposed at central Saudi Arabia. The
studied material comes from the Tuwaiq Mountain and Hanifa formations at the Khashm al Qaddiyah, Dirab, Jabal al Abakkayn and Maáshabah
sections. Thirteen species are identified, described and illustrated. Among them, a new Aporrhais species (A. sauditica sp. nov.) is introduced. In
addition, two further possible new Pseudomelania species from the same strata are mentioned. Other members of the assemblage include
Kosmomphalus? sp. aff. K. reticulatus Fischer, Bourguetia? sp. aff. B. saemanni (Oppel), Bourguetia? sp., Ampullospira sp., Globularia? sp. cf.
G. bajociana Fischer, Purpuroidea sp. aff. P. glabra Morris and Lycett, Purpuroidea sp., Cossmannea sp. aff. C. desvoidyi (d’Orbigny), Cryptoplocus sp. aff. C. depressus (Voltz) and Actaeonina? sp. Stratigraphically, seven species of this gastropod assemblage were only reported from the Middle Jurassic, whereas the other six ones are extending from the Middle to the Upper Jurassic of the studied succession. As compared with their gastropod content, the Khashm al Qaddiyah represents the richest section (33 out of 68 specimens, 48.5%), whereas the Maáshabah section showed an impoverished gastropod assemblage (only three specimens, 4.4%). The species reported here show paleobiogeographical affinities with coeval gastropod assemblages from India, east Africa, Middle East (Israel, the Sinai of Egypt) and western Tethys. The identified species confirm three depositional settings: open shelf lagoon, shoal/fore-shoal and open marine environments. The lower degree of fragmentation, poor sorting and scarcity of abrasion indicate a parautochthonous faunal assemblage.
Key words: gastropods, Middle–Upper Jurassic, systematics, paleoecology, paleoenvironment, central Saudi Arabia.
Utilizing U–Pb CA-TIMS dating to calibrate the Middle to Late Jurassic spore-pollen zonation of the Surat Basin, Australia to the geological time-scale
C. C. WAINM AN , C. HANNAFORD, D. MANTLE and P. J. MCCABE
Spore-pollen palynostratigraphy is commonly used to subdivide and correlate Jurassic continental successions in eastern Australia and thus aid the
construction of geological models for the petroleum and coal industries. However, the current spore-pollen framework has only been tenuously
calibrated to the geological time-scale. Age determinations are reliant on indirect correlations of ammonite and dinoflagellate assemblages from
New Zealand, the North West Shelf of Australia and Southeast Asia to the standard European stages. New uranium-lead chemical abrasion thermal ionization mass spectrometry (U–Pb CA-TIMS) dates from 19 tuff beds in the Middle–Upper Jurassic Injune Creek Group of the Surat Basin enables regional spore-pollen palynostratigraphic zones to be precisely dated for the first time. These results show the base of the APJ4.2 and APJ4.3 subzones are similar in age to previous estimates (Middle Jurassic, Bathonian) from indirect palynostratigraphic correlation. However, the base of the APJ5 Zone and the APJ6.1 Subzone may be somewhat younger than previously estimated, possibly by as much as 2.5 and 4.2 Myrs, respectively. The continued utilization of U–Pb CA-TIMS dates will further refine the absolute ages of these zones, improve the inter- and intra-basinal correlation of Middle–Upper Jurassic strata in eastern Australian basins and greatly enhance intercontinental correlations.
Key words: U–Pb CA-TIMS, tuffs, palynostratigraphy, Surat Basin, Jurassic.
