Paleozoic glaciation in NE Africa: field and remote sensing-based evidence from the South Eastern Desert of Egypt

ABSTRACT

Exhumed Paleozoic glacial deposits and landforms of the North Gondwana are reported here for the first time from the South Eastern Desert (SED) of Egypt. Using field observations and remote sensing datasets (Advanced Land Observing Satellite [ALOS], Phased Array L-band Synthetic Aperture Radar [PALSAR] radar, multispectral Landsat TM datasets, and digital elevation models [DEMs]), we mapped the distribution of Paleozoic glacial features (i.e. deposits and landforms) in the SED. Two main glaciogenic facies were identified in three locations in the SED: (1) massive, poorly sorted, matrix supported, boulder-rich diamictites in Wadi El-Naam and Korbiai, and (2) moderately-sorted, occasionally bedded outwash deposits in Betan area. Inspection of radar, DEMs, and Landsat Operational Land Imager (OLI) images revealed previously unrecognized ENE-WSW trending glacial megalineations (MLs) over the peneplained Neoproterozoic basement rocks in the central sections of the SED, whose trends align along their projected extension with those of glacial features (tunnel valleys and striation trends) reported from Saudi Arabia. The glaciogenic features in the SED are believed to be largely eroded during the uplift associated with the Red Sea opening, except for those preserved as basal units beneath the Nubia Sandstone Formation or as remnant isolated deposits within paleo-depressions within the basement complex. The apparent spatial correlation of the SED glacial features with well-defined Late Ordovician deposits in North Africa and in Saudi Arabia, and the reported thermochronometric analyses and fossil records are consistent with a Late Ordovician age for the SED glaciogenic features and support models that call on the continuation of the Late Ordovician (Hirnantian) ice sheet from the Sahara into Arabia through the SED of Egypt.     

昆明二村下奥陶统红石崖组顶部Cruziana rugosa遗迹化石群落的沉积环境和生态特征

Cruziana及其相关的遗迹化石是由底栖三叶虫在沉积物表面停歇、爬行所留下的遗迹,一般认为产于潮下带至浅海陆棚环境,具有古水深指示意义。然而,本文通过对昆明民富二村下奥陶统红石崖组顶部含Cruziana rugosa遗迹化石群落层位的沉积环境分析却发现,Cruziana rugosa遗迹化石群落的沉积环境为潮上带—潮间带,说明三叶虫可以在短暂暴露环境中活动。三叶虫的这种适应性活动可能为节肢动物从海洋走向陆地做好了进化准备。     

云南临沧晚中新世一种水龙骨科植物化石的修订及其生物学意义

云南现代真蕨类植物资源丰富,蕨类植物多样性的地史起源,必须从化石记录入手。在云南临沧上中新统邦卖组植物化石采集中发现了槲蕨属1块不育叶和2块腐殖叶的新材料,这些标本为修订Drynaria propinqua Wen et al.,2013,以及揭示该种不育叶和腐殖叶的特征提供了新的材料。通过与槲蕨属国内外报道的化石种和现生种的详细比较,将其重新定名为Drynaria cf.propinqua。Drynaria cf.propinqua的发现,表明云南临沧晚中新世的气候与现今中国西南地区温暖湿润的气候类似,这些附生植物的生活习性表明,临沧地区复杂分层的森林生态系统至少在晚中新世已经确立。     

First recorded evidence in the fossil record of snipe flies (Diptera: Rhagionidae) in Cretaceous amber, France

Novelaria, a new genus of rhagionid of late Albian age with three new species, is the first record of this family from Charentes amber (southwestern France). The new genus is probably closely related to the recent genus Chrysopilus. However its relationship with the other fossils in amber is discussed. A key for separation of the new species is provided and the diversity of the family during the Cretaceous is also briefly discussed.     

A Middle Ordovician crinoid from the beach gravels of Ristna Cape,Hiiumaa Island,Estonia

Reworked fossils may be exotic, but more typically are locally derived. Echinoderms have only rarely been identified from beach clasts; most commonly, these are Upper Cretaceous echinoids from the Chalk. A pebble collected from a beach in Estonia has yielded a moderately well preserved specimen of the crinoid stem, Baltocrinus (col.) antiquus (Eichwald). This species is typical of the Baltic region, only being known from the Middle Ordovician (Darriwilian) of Estonia, but is exotic because the local outcrop is Upper Ordovician to Silurian.     

A fossil aardvark (Mammalia, Tubulidentata) from the lower Pliocene of Chad

The Mission Paléoanthropologique Franco-Tchadienne (MPFT) found a new species of Orycteropodidae (Mammalia, Tubulidentata) in the Kollé fossiliferous sector, northern Chad. After Orycteropus abundulafus [Journal of Vertebrate Paleontology 20 (1) (2000) 205–209; Lehmann, T., Vignaud, P., Likius A., Brunet M., in press. A new Orycteropodidae (Mammalia, Tubulidentata) in the Mio-Pliocene of Northern Chad. Zool. J. Linnean Soc.], this specimen is the second complete skeleton of fossil aardvark found in the Djurab desert. It is the first complete representative of an Orycteropus species found in the Pliocene of Africa. In regard to the Miocene fossil aardvarks, this new taxon, Orycteropus djourabensis nov. sp., shows more affinities with the extant O. afer. The main differences are the larger teeth and the shorter hand in the fossil form. Kossom Bougoudi and Kollé represent a chronological series that gives a unique opportunity for studying the evolution of the African Tubulidentata around the Mio-Pliocene boundary (5.5-4 My). The new species is distinct from the older Chadian Orycteropodid from KB and it embodies the taxonomic turnover that took place within the order Tubulidentata around this boundary in Africa. Moreover, this new species is the oldest known Orycteropus species that clearly belongs to the modern forms including the extant aardvark.     

Molecular and carbon isotopic analysis of individual biological markers: evidence for sources of organic matter and paleoenvironmental conditions in the Upper Ordovician Maquoketa Group, Illinois Basin, U.S.A.

Variations in the carbon isotopic composition (δ¹³C) of pristane, phytane, n-heptadecane (n-C₁₇), C₂₉ ααα 20R sterane, and aryl isoprenoids provide evidence for a diverse community of algal and bacterial organisms in organic matter of the Upper Ordovician Maquoketa Group of the Illinois Basin. Carbon isotopic compositions of pristane and phytane from the Maquoketa are positively covariant (r = 0.964), suggesting that these compounds were derived from a common source inferred to be primary producers (algae) from the oxygenated photic zone. A variation of 3‰ in δ¹³C values (−31 to −34‰) for pristane and phytane indicates that primary producers utilized variable sources of inorganic carbon. Average isotopic compositions of n-C₁₇ (−32‰) and C₂₉ ααα 20R sterane (−31‰) are enriched in ¹³C relative to pristane and phytane (−33‰) suggesting that these compounds were derived from a subordinate group of primary producers, most likely eukaryotic algae. In addition, a substantial enrichment of ¹³C in aryl isoprenoids (−14 to −18‰) and the identification of tetramethylbenzene in pyrolytic products of Maquoketa kerogen indicate a contribution from photosynthetic green sulfur bacteria to the organic matter. The presence of anaerobic, photosynthetic green sulfur bacteria in organic matter of the Maquoketa indicates that anoxic conditions extended into the photic zone.The δ¹³C of n-alkanes and the identification of an unusual suite of straight-chain n-alkylarenes in the m/z 133 fragmentograms of Ordovician rocks rich in Gloeocapsomorpha prisca (G. prisca) indicate that G. prisca did not contribute to the organic matter of the Maquoketa Group.     

Ophiomorpha irregulaire, rare trace fossil in shallow marine sandstones, Cretaceous Atane Formation, West Greenland

Ophiomorpha irregulaire is a large and extremely rare trace fossil. The type section is in the Book Cliffs, Utah, USA. A second on-shore locality is reported here, in the Nuussuaq Basin of West Greenland. Both occurrences date from the Late Cretaceous. Other reports of O. irregulaire are restricted to two-dimensional sections in well cores and are mostly Jurassic in age. The West Greenland occurrence is in the Atane Formation in shallow marine clean sandstone. The two on-shore localities lie in the same biogeographical region, in connection with the Cretaceous Western Interior Seaway of North America. O. irregulaire is characterized by a sinuous, branched meander maze lying mostly within a single horizontal plane, probably not far beneath the seafloor. The burrow lining has remarkably elongate pellets that probably were emplaced by the burrower. In some cases, diagenetic compression may have deformed the lining pellets to produce their elongated shape. The muddy sediment comprising the lining is almost unrepresented in the clean sands of the substrate, and it was probably trapped from suspension during suspension-feeding activity.     

滇中川街盆地中侏罗世弓鲛(软骨鱼类)化石新材料

云南禄丰县川街盆地中侏罗统产出弓鲛鱼类化石后甸弓鲛(Hybodus houtienensis Young)、新庄弓鲛(新种)(Hybodus xinzhuangensis Sun)、川街弓鲛(新种)(Hybodus chuanjieensis Sun)。后甸弓鲛(Hybodus houtienensis Young)是中国发现最早的弓鲛鱼类之一,正型标本为破碎的鳍棘,副型标本为一枚牙齿齿冠。依据在川街盆地相同层位发现的新化石材料,对后甸弓鲛副型标本进行了增补,补充了描述,建立了2个弓鲛新种:新庄弓鲛与川街弓鲛,丰富了"后甸弓鲛带"弓鲛类群,并讨论了弓鲛属的生物地层、生活的古环境和地理分布特征。     

Phosphatized Punctatus with mouthparts and its embryo fossils from the Lower Cambrian of Ningqiang, south Shaanxi, China

The appearance of coelenterates marks the real beginning of metazoan evolution. It therefore has a prominent position in the origin and evolutionary history of organisms, and is also a pivotal question of evolutionary biology. Punctatus is an extinct, ancient marine animal from the early stage of the Cambrian explosion, occurring at the lowermost Cambrian of both Kuanchuanpu (Ningqiang, Shaanxi) and Maidiping (Emei, Sichuan) areas. Punctatus has been studied for many years since the discovery of its fragments. Systematic and phylogenetic analysis has long been limited because of the rarity of complete specimens. In order to improve research into Punctatus, more than ten thousand globular fossils were recovered by means of “Chemistry Retting”. On the basis of the study of these globular fossils, a series of Punctatus fossils with cone parts and finely preserved soft-tissue mouthparts and fossilized metazoan embryo were recovered. Through research on characteristics such as shape, modality and structure of these fossils symbiotic with Punctatus emeiensis, the author found many possible embryo fossils including the evidence of gastrula-stage animal fossils. The sequence of fetation might have appeared on the corolliform oral region of Punctatus emeiensis. A study of the soft tissues, functional morphology and the sequence of embryo fossils shows evidence that Punctatus resembles coelenterate polyps in systematic classification. Perhaps it also represents an ancestor of the coelenterate with an original tentacle. A comparison with the real “tentacle animal” found in the Chengjiang Fauna, shows that the original tentacle is very tiny and its function range is limited. This reveals the primitive nature of the animal. Although the original tentacle is so small, it does exist, representing the first big step towards the real flexible tentacle with a strong function from the early evolving tentacle. Translated from Journal of Acta Palaeontologica Sinica, 2006, 45(2): 182–194 [译自: 古生物学报]     

湖南桃源郝坪奥陶系五峰组顶部斑脱岩LA-ICP-MS锆石U-Pb年龄

为了认识奥陶纪-志留纪之交的火山活动及事件年龄,对湖南桃源郝坪剖面的斑脱岩进行了LA-ICP-MS锆石U-Pb定年。结果表明,五峰组顶部斑脱岩LA-ICP-MS锆石U-Pb年龄为442.2±8.1Ma,该年龄反映了扬子地区奥陶纪-志留纪之交火山活动的时代,与国际地层委员会公布的奥陶系-志留系界线年龄(443.7±1.5Ma)相一致,同属晚奥陶世。奥陶纪-志留纪之交的火山活动对于探讨晚奥陶世生物绝灭、沉积环境变化与年代地层对比具有重要的意义。     

Similar morphological and chemical variations of Gloeocapsomorpha prisca in Ordovician sediments and cultured Botryococcus braunii as a response to changes in salinity

Most Ordovician source rocks consist of accumulation of a colonial marine microorganism, Gloeocapsomorpha prisca (G. prisca) whose nature, ecology and affinity with extant organisms have been in dispute for years. Furthermore, recent studies have shown major differences in phenol moieties between two G. prisca-rich samples. Examination of five G. prisca-rich kerogens by electron microscopy and pyrolysis studies revealed (i) the occurrence of two markedly distinct “morpho/chemical” types: a “closed/phenol-rich” type (Baltic samples) and an “open/phenol-poor” one (North American samples) and (ii) the selective preservation of the resistant micromolecular material building up the thick cell walls in the original organism. Comparison with extant Botryococcus braunii (a widespread green microalga) grown on media of increasing salinity suggests that G. prisca is likely to be a planktonic green microalga related to B. braunii, which can adapt to large salinity variations which, in turn, control its polymorphism. The large differences in colony morphology and in the content of phenol moieties observed in fossil G. prisca and the resulting occurrence of two “morpho/chemical” types, should therefore reflect depositional environments with different salinities. The presence of thick, highly aliphatic, resistant walls in G. prisca selectively preserved during fossilization, accounts for the major contribution of this organism to Ordovician organic-rich sediments and for the resulting typical signature of Ordovician oils.     

New specimens of a fossil ostrich from the Miocene of Kenya

Fossilised hind limb bones from the late Middle Miocene (approximately 14 million-year-old [MYA]) Fort Ternan, Kadianga West and Ngorora localities in Western Kenya indicate the presence of a new representative of the ostrich genus Struthio. These new fossils represent some of the oldest known records for Struthio yet described, slightly younger than Struthio coppensi, from the Lower Miocene of Namibia. Because the four sub-species of the modern-day ostrich (Struthio camelus camelus, Struthio camelus australis, Struthio camelus massaicus, and Struthio camelus molybdophanes) inhabit the plains of Africa, and as recently as the 1940s, a fifth sub-species was also present in the Middle East and Saudi Arabia (Struthio camelus syriacus), records of Struthio from Kenya and Namibia testify to the much wider distribution of these cursorial birds in the relatively recent past. This is further supported by the very high frequency of ostrich eggshell fragments found across Africa and Eurasia, which vastly outweighs the amount of skeletal material uncovered over the last century.     

塔中古溶洞见证晚奥陶世抬升幅度

塔中隆起区上奥陶统良里塔格组灰岩与桑塔木组砂—粉砂岩之间为不整合接触,昭示着这两个组沉积期之间存在一次历时约百万年的区域性构造抬升事件。中古31井良里塔格组三段的4 125.6～4 133.9 m井段为垮塌型溶洞沉积,洞顶距良里塔格组二段顶部190.6 m,溶洞中角砾状充填物主要来自良里塔格组洞壁本身的礁相灰岩,且见数厘米厚的暗河流水沉积纹层,未发现源于其它时代的颗粒混杂其间。这一事实指证了溶洞的形成和充填时代均为良里塔格组沉积之后、桑塔木组覆盖之前的晚奥陶世凯迪中期。具溶蚀力的淡水潜流带的深度一般不低于周围的海平面,由此可推断出该井区这次抬升出海平面之上的高度,即使忽略良里塔格组顶部可能经地表剥蚀的良里塔格组一段,抬升出水面部分至少也应该有190 m,藉生态地层学恢复洞壁礁灰岩沉积时的海水深度约为30 m±,因此总抬升幅度至少能达到220 m。     

Anurans from the Candeleros Formation (?Cenomanian-Turonian) of west-central Argentina: new evidence for pipoid evolution

The fluvio-lacustrine deposits of the ?Cenomanian-Turonian Candeleros Formation in the northwestern fringe of Patagonia have yielded numerous remains of vertebrates, including anurans. A new, partially articulated immature specimen of a small pipimorph pipoid from the upper part of this unit is described herein. Although incompletely preserved, the morphology and proportions of the skeleton are strongly reminiscent of corresponding elements of the holotype of Avitabatrachus uliana from the lower section of the same formation at a nearby locality, thus suggesting that these specimens might represent the same, or a closely related, taxon. The new specimen is a metamorphosing individual: it has a zygapophyseal articulation between the sacrum and the neural arch of a postsacral vertebra that bears conspicuous transverse processes, and four pairs of ribs. These traits are not present in the available material of A. uliana, but they might have occurred within the normal range of variation of a single species. Although the generic and specific allocation of the new material is uncertain, a parsimony analysis performed to clarify the relationships of A. uliana supports a phylogenetic placement of this taxon outside the crown Pipidae. The evidence provided by the Candeleros anurans confirms the presence of stem pipids in Patagonia in the early Late Cretaceous.     

Kumamotoa, an early Late Cretaceous non-marine bivalve, from Fujian, south China

The non-marine bivalve species Trigonioides (Kumamotoa) quadratus Gu and Ma is described from the Fourth Member of the Hekou Formation in western Fujian, southeastern China. This species previously was regarded to belong to the subgenus Trigonioides (s.s.), which is restricted to the Early Cretaceous. Herein, it is included into the subgenus Kumamotoa. It is compared to Cenomanian (early Late Cretaceous) species from Japan and Korea such as Trigonioides (Kumamotoa) mifunensis Tamura, Trigonioides (Kumamotoa) matsumotoi Kobayashi and Suzuki and Trigonioides (Kumamotoa) paucisulcatus Suzuki. The age of the Fourth Member of the Hekou Formation is discussed.     

The oldest barnacle from the Caribbean is a rudist bivalve (Maastrichtian, Jamaica)

Four new specimens of Euscalpellum? coatesi Donovan and Davis-Strickland from the Maastrichtian of Jamaica are described; two of these occur in association with the right valve of the rudistid bivalve Chiapasella radiolitiformis (Trechmann). This demonstrates that E.? coatesi is not a barnacle, but rather represents an unusual preservational state of the left valve of C. radiolitiformis retaining only the cellular inner part of the shell.     

A diverse Rancholabrean vertebrate microfauna from southern California includes the first fossil record of ensatina (Ensatina eschscholtzii: Plethodontidae)

Analysis of late Pleistocene fossils recovered from near the Huntington Beach, California (USA), pier (site LACM 7679) has revealed a diverse fauna dating to approximately 40 ¹⁴C ka BP. Extinct megafauna (three genera) are present; however, a microfauna including three genera of fish, five genera of amphibians, twelve genera of reptiles, two genera of birds, and ten genera of small mammals dominates the assemblage in terms of diversity. Additional identification of seven genera of non-marine mollusks and various macro- and microscopic plant remains including grasses, three families of herbs, and seven genera of trees provides a wealth of information concerning the past ecology of what is currently a coastal dune field complex. During the Rancholabrean Period, the LACM 7679 locality was approximately 10 km inland from the Pleistocene coastline and contained lush riparian zones interspersed with coastal sage scrub, a few trees, and grasslands teeming with a variety of small and large animals.