ORIGIN, EVOLUTION AND CLASSIFICATION OF THE NEW SUPERORDER NEPIOMORPHIA (MOLLUSCA, BIVALVIA, LOWER PALAEOZOIC)

Abstract: A number of bivalve taxa defined in the past as ‘Cryptodonten’ by Neumayr, 1884 were grouped together in the high‐level taxon Palaeoconchae Neumayr, 1884. Cox (1969) noted that Palaeoconchae and Cryptodonta were synonymous and Newell (1969) used Cryptodonta as a subclass of bivalves. However, for the past 120 years, the Cryptodonta has been poorly conceptualized and the name was used for poorly understood genera or those lacking dentition. As used by Newell, Cryptodonta included taxa now placed in the subclasses Protobranchia Pelseneer and Autolamellibranchiata Grobben, and to the class Rostroconchia Pojeta, Runnegar, Morris and Newell. The bulk of Newell's use of Cryptodonta was made up of Silurian and Devonian taxa first described by Barrande (1881) from Bohemia; Newell placed these in the order Praecardioida Newell. In effect, Cryptodonta became a ‘wastebasket’ grouping for what, at the time, were poorly understood taxa. Many of the formerly poorly understood praecardioids are now better known and are herein placed in the new superorder Nepiomorphia. The Nepiomorphia contains two orders: (1) order Praecardioida that includes the families Slavidae K?í?, Cardiolidae Hoernes, Praecardiidae Hoernes and Buchiolidae Grimm; and (2) new order Antipleuroida that includes the families Stolidotidae fam. nov., Spanilidae fam. nov. and Antipleuridae Neumayr. The Nepiomorphia originated probably in the early Silurian as result of r‐selection progenesis. When the marine current system became re‐established after the late Ordovician glaciation and in the early Silurian, an at least temporary ventilation of the shallow waters by surface currents was renewed in higher latitudes of peri‐Gondwana and Siberia, producing acceptable sea‐bottom environments. Larvae were distributed by surface currents from the warm tropical regions of Laurentia and Baltica and were among the first benthic organisms to colonize the new environments. Temporary ventilation created frequent density‐independent catastrophic mortalities of early ontogenetic stages, with no competitors and with super‐abundant resources. During the Silurian and early Devonian, the Nepiomorphia underwent several diversifications in the recurring cephalopod limestone biofacies characteristic of peri‐Gondwana, and evolved infaunal, semi‐infaunal and epifaunal modes of life in several lineages. The Nepiomorphia most probably became extinct during the early Carboniferous and had no role in the future evolution of the Bivalvia.     

Temperature-dependent population growth of three species of stored product mites (Acari: Acaridida)

The pest potential of stored product mites depends on the reproduction rate that is affected by the environmental conditions. In this study we investigated the effect of temperature, ranging from 5 to 35°C, on the population growth of three important mite species, Acarus siro, Tyrophagus putrescentiae and Auleroglyphus ovatus at 85% r.h. Starting with 10 individuals the population increase of mites was observed after 3 weeks of cultivation, or after 6 weeks for those kept at low temperatures (5, 10, 12.5, and 15°C). The rate of increase was calculated for each temperature and species. The obtained data were fitted with polynomial models. The mite population growth rates increased with increasing moderate temperatures until 25°C, when r _m -values were 0.179, 0.177 and 0.190 for A. siro, A. ovatus and T. putrescentiae, respectively. The lower development threshold was 10.2°C in all three species. Estimated upper temperature threshold was higher in T. putrescentiae (49°C) than in A. siro and A. ovatus (38°C). Simulation of the rate of population increase under ideal conditions, using real temperature records obtained from Czech grain stores, showed that the pest mite populations increase only during 3.5 months within a typical 9-month storage season in Central Europe. These results indicate that control of mites, be it chemical, physical or biological, is recommended during the months when allergens and pests are produced, i.e. from September to mid November and in May.     

In-vivo intratissue ablation by nanojoule near-infrared femtosecond laser pulses

Non-invasive intratissue ablation was performed in the cornea of living rabbits by using 80 MHz near-infrared intense nanojoule femtosecond laser pulses. The intratissue surgical effect was induced by multiphoton absorption at a wavelength of 800 nm and was ascertained by histological examination. Highly precise intratissue ablation was obtained with no detrimental effects to the overlying or underlying layers. Activated keratocytes in the laser-treated corneas were detected with two-photon imaging postoperatively. Intratissue femtosecond laser ablation thus has potential as a effective technique in refractive surgery for the treatment of visual disorders. This work was supported in part by the German Science Foundation.     

柴达木盆地北缘昆特依凹陷始新统下干柴沟组微体古生物研究

昆2井是柴达木盆地北部昆特依凹陷区潜伏Ⅰ号构造上的第一口勘探井,为了建立该地区地层层序,对该井的岩屑及岩芯样品进行了系统的微体古生物学研究,仅在下干柴沟组发现少量轮藻化石和零星的介形类化石。下干柴沟组下段出现的轮藻类Gyrogona qianjiangica和Lamprothamnium? brevis是我国中始新世最常见的化石。该层段的轮藻类可命名为Gyrogona qianjiangica-Lamprothamniumcurta-L. brevis组合,时代为中、晚始新世。本文以Gyrogona qianjiangica分布的顶、底界作为昆2井下干柴沟组下段的标志,划分结果与其它轮藻及介形类化石的对比结果基本一致。氯离子含量分布显示,轮藻类化石产出的下干柴沟组是整个地层剖面中含盐度最低的沉积阶段,表明下干柴沟组沉积时期,该地区处于水域比较广阔的淡水湖泊环境,但在个别层段出现咸化环境,产出以喜盐的Austrocypris为代表的介形类化石。     

Explaining Leaf Herbivory Rates on Tree Seedlings in a Malaysian Rain Forest

Seedlings of five species of dipterocarp trees were planted in experimental plots in rain forest gaps in Sabah, Malaysia, and the rates of herbivory on their mature leaves recorded over 6 mo. A novel method was used to estimate the feeding pressure exerted by the local insect herbivore community, derived from the relative abundances of the dominant generalist herbivores and their feeding preferences. Characteristics of the leaves related to their defense and nutritional value were measured—phenolic content, laminar fracture toughness, laminar thickness, and nitrogen content. Three main groups of herbivorous insects were present—coleopteran and lepidopteran herbivores, which were sampled by hand from the seedlings, and orthopteran herbivores, which were sampled by sweep netting. The feeding preferences of the main coleopteran and orthopteran herbivores were determined using laboratory feeding trials. Combining variables in a Principal Components Analysis, a clear separation was found between the five seedling species along the first extracted component. This correlated closely with herbivory rates between species. The first extracted component comprised a negative influence of phenolic content and positive effects of nitrogen content, laminar fracture toughness, abundances of coleopteran and lepidopteran herbivores, and estimated feeding pressure of the coleopteran community. Further studies are required to determine the potential applications of the latter measure of estimated herbivore community impact.     

Dinosaur footprints from the Early Jurassic of Le Mazel (Lozère,Southern France)

During the 20^th century, the first dinosaur tracks of the Causses Basin were identified at Saint-Laurent-de-Trèves, in the Parc National des Cévennes (southern France). A recent excavation reveals a new theropod tracksite in the Hettangian deposits from Le Mazel, 2 km from the historical tracksite at Saint-Laurent-de-Trèves. The tracks are here described combining a biometric approach and 3D imaging photogrammetry. The main track-bearing surface bears 64 in situ tridactyl footprints preserved as concave epireliefs. Two morphotypes were identified, a “Grallatorid” morphotype and a “Kayentapus” morphotype. Footprints belonging to the first morphotype are closely similar to Grallator lescurei, Grallator minusculus, and Grallator sauclierensis. This study shows the difficulty to distinguish quite similar tridactyl tracks from an ichnotaxonomic point of view and highlights the importance of detailed biometric comparisons. Tracks are preserved in a brown to yellowish dolomudstone showing abundant cryptalgal laminites and mud cracks. These deposits were accrued in shallow environments such as intertidal and supratidal zones of a tidal flat.     

Linear relationship between electromyography and shear wave elastography measurements persists in deep muscles of the upper extremity

Recent works have demonstrated a linear relationship between muscle activation and shear modulus in various superficial muscles. As such, it may be possible to overcome limitations of traditional electromyography (EMG) methods by assessing activation using shear wave elastography. However, the relationship has not been wholly validated in deep muscles. This study measured the association between squared shear wave velocity, which is related to shear modulus, and activation within superficial and deep muscles. This relationship was also compared between surface and intramuscular EMG electrodes. We simultaneously recorded EMG and shear wave velocity in one deep (brachialis) and one superficial (brachioradialis) muscle in ten healthy individuals during isometric elbow flexion across a wide range of contraction intensities. Muscle activation and squared shear wave velocity demonstrated good reliability (ICC > 0.75) and showed a linear relationship (P < 0.05) for all muscle/EMG electrode type combinations (study conditions) after down-sampling. Study condition was not a significant within-subject factor to the slope or intercept of the relationship (P > 0.05). This work demonstrates that activation of both superficial and deep muscles can be assessed noninvasively using ultrasound shear wave elastography and is a critical step toward demonstrating elastography’s utility as an alternative to EMG.     

Découverte des sites du Paléolithique inférieur au Nord de l’Arménie

For a long time, the scientific community assumed that the Acheulean culture was expressed on the territory of the Armenian Plateau as well as in the neighboring regions of the Caucasus only by its late phase; therefore, it appeared in the second half of the Middle Pleistocene. In recent years, the Armenian-Russian mission has discovered and studied much older Acheulean industries sites, located in northern Armenia (the Lori intermountain Depression). These industries, represented by archaic type tools (large hand axes, picks, choppers, chisel-like tools, scrapers, points, etc.), are discovered in three deposits of origin of proluvial genesis. In the Karakhach site, this type of industry is deposited in the lower levels of volcanic tuff and below; the U/Pb study of this level of tuff proposes a series of dates, assigned to the time interval between 1.944 + 0.046 and 1.75 + 0.02 Ma. The paleomagnetic study demonstrated the inverse polarity on the tuff and the normal polarity of the underlying deposits; in correlation with other dating, this fact allows to attribute the Acheulean layers of the site of Karakhatch to the Lower Pleistocene, in particular to the Oldoway episode and to the Upper Matuyama time period. The estimated age and the techno-morphological characteristics of the tools indicate the Lower Acheulean period. The dating of the Muradovo site does not seem possible, however its very old industries and the archaeological layers, where they were discovered, find equivalents in the layered layer, surmounted by tuffs, of the Karakhatch site. The Kutran I site presented a paleosol sequence with similar Acheulean tools (hand axes, picks, choppers, etc.). Its oldest layer is older than 1.5 Ma, the upper layer is attributed to the early Middle Pleistocene; this fact means that it is possible to speak of the Lower Acheulean and of its transition to the Middle Acheulean period. The specific character and the age of the Lower Acheulean of Armenia admit that it could have formed independently of the Lower Acheulean of Africa, whose estimated age does not rise before 1.76 Ma. It should also be noted that on the neighboring territory of Georgia about the same time when appeared the Acheulean culture in Armenia, the Oldowan Dmanisi site already existed.     

Biomechanical contributions of upper cervical ligamentous structures in Type II odontoid fractures

Fractures of the odontoid present frequently in spinal trauma, and Type II odontoid fractures, occurring at the junction of the odontoid process and C2 vertebrae, represent the bulk of all traumatic odontoid fractures. It is currently unclear what soft-tissue stabilizers contribute to upper cervical motion in the setting of a Type II odontoid fracture, and evaluation of how concomitant injury contributes to cervical stability may inform surgical decision-making as well as allow for the creation of future, accurate, biomechanical models of the upper cervical spine. The objective of the current study was to determine the contribution of soft-tissue stabilizers in the upper cervical spine following a Type II odontoid fracture. Eight cadaveric C0-C2 specimens were evaluated using a robotic testing system with motion tracking. The unilateral facet capsule (UFC) and anterior longitudinal ligament (ALL) were serially resected to determine their biomechanical role following odontoid fracture. Range of motion (ROM) and moment at the end of intact specimen replay were the primary outcomes. We determined that fracture of the odontoid significantly increases motion and decreases resistance to intact motion for flexion–extension (FE), axial rotation (AR), and lateral bending (LB). Injury to the UFC increased AR by 3.2° and FE by 3.2°. ALL resection did not significantly increase ROM or decrease end-point moment. The UFC was determined to contribute to 19% of intact flexion resistance and 24% of intact AR resistance. Overall, we determined that Type II fracture of the odontoid is a significant biomechanical destabilizer and that concurrent injury to the UFC further increases upper cervical ROM and decreases resistance to motion in a cadaveric model of traumatic Type II odontoid fractures.