Killing in the Pliocene: shark attack on a dolphin from Italy

Abstract: Shark bite marks, including striae, sulci and abrasions, in a well‐preserved fossil dolphin skeleton referred to Astadelphis gastaldii (Cetacea, Delphinidae) from Pliocene sediments of Piedmont (northern Italy), are described in detail. The exceptional combination of a fossil dolphin having a significant part of the skeleton preserved and a large number of bite marks on the bones represents one of the few detailed documentations of shark attack in the past. Most bite marks have been referred to a shark about 4 m long with unserrated teeth, belonging to Cosmopolitodus hastalis, on the basis of their shape and their general disposition on the dolphin skeleton. According to our hypothesis, the shark attacked the dolphin with an initial mortal bite to the abdomen from the rear and right, in a similar way as observed for the living white shark when attacking pinnipeds. A second, less strong, bite was given on the dorsal area when the dolphin, mortally injured, probably rolled to the left. The shark probably released the prey, dead or dying, and other sharks or fishes probably scavenged the torn body of the dolphin.     

Variation in enamel development of South African fossil hominids

Dental tissues provide important insights into aspects of hominid palaeobiology that are otherwise difficult to obtain from studies of the bony skeleton. Tooth enamel is formed by ameloblasts, which demonstrate daily secretory rhythms developing tissue-specific structures known as cross striations, and longer period markings called striae of Retzius. These enamel features were studied in the molars of two well known South African hominid species, Australopithecus africanus and Paranthropus robustus. Using newly developed portable confocal microscopy, we have obtained cross striation periodicities (number of cross striations between adjacent striae) for the largest sample of hominid teeth reported to date. These data indicate a mean periodicity of seven days in these small-bodied hominids. Important differences were observed in the inferred mechanisms of enamel development between these taxa. Ameloblasts maintain high rates of differentiation throughout cervical enamel development in P. robustus but not in A. africanus. In our sample, there were fewer lateral striae of Retzius in P. robustus than in A. africanus. In a molar of P. robustus, lateral enamel formed in a much shorter time than cuspal enamel, and the opposite was observed in two molars of A. africanus. In spite of the greater occlusal area and enamel thickness of the molars of both fossil species compared with modern humans, the total crown formation time of these three fossil molars was shorter than the corresponding tooth type in modern humans. Our results provide support for previous conclusions that molar crown formation time was short in Plio-Pleistocene hominids, and strongly suggest the presence of different mechanisms of amelogenesis, and thus tooth development, in these taxa.     

Application of morphologic burrow interpretations to discern continental burrow architects: Lungfish or crayfish?

A methodology for trace fossil identification using burrowing signatures is tested by evaluating ancient and modern lungfish and crayfish burrows and comparing them to previously undescribed burrows in a stratigraphic interval thought to contain both lungfish and crayfish burrows. Permian burrows that bear skeletal remains of the lungfish Gnathorhiza, from museum collections, were evaluated to identify unique burrow morphologies that could be used to distinguish lungfish from crayfish burrows when fossil remains are absent. The lungfish burrows were evaluated for details of the burrowing mechanism preserved in the burrow morphologies together forming burrowing signatures and were compared to new burrows in the Chinle Formation of western Colorado to test the methodology of using burrow signatures to identify unknown burrows.

Permian lungfish aestivation burrows show simple, nearly vertical, unbranched architectures and relatively smooth surficial morphologies with characteristic quasi‐horizontal striae on the burrow walls and vertical striae on the bulbous terminus. Burrow lengths do not exceed 0.5 m. In contrast, modern and ancient crayfish burrows exhibit simple to highly complex architectures with highly textured surficial morphologies. Burrow lengths may reach 4 to 5 m.

Burrow morphologies unlike those identified in Gnathorhiza aestivation burrows were found in four burrow groups from museum collections. Two of these groups exhibit simple architectures and horizontal striae that were greater in sinuosity and magnitude, respectively. One of these burrows contains the remains of Lysoro‐phus, but the burrow surface reveals no reliable surficial characteristics. It is not clear whether Lysorophus truly burrowed or merely occupied a pre‐existing structure. The other two groups exhibit surficial morphologies similar to those found on modern and ancient crayfish burrows and may provide evidence of freshwater crayfish in the Permian.

Burrows from the Upper Triassic Chinle Formation in western Colorado exhibit simple to moderately complex architectural morphologies, ranging from predominantly vertical, unbranched, with little or no chamber development to predominantly vertical, few branches, and with minor chamber development. Surficial burrow morphologies are moderate to highly textured. The burrows have scrape marks, scratch marks, mud and lag‐liners, knobby surfaces, pleopod striae, and body impressions.

Although no fossil remains of the burrowing organism were found within or associated with the Chinle burrows from western Colorado, the similarity of architectural and surficial burrow morphologies to those in the Chinle of Canyonlands, Utah and to modern crayfish burrows, clearly indicates that the Colorado burrows are the product of burrowing crayfish rather than lungfish. Evaluation of burrowing signatures preserved in the architectural and surficial burrow morphologies is a very useful tool to compare and contrast Chinle burrows from different regions on the Colorado Plateau. Documentation of crayfish burrows in the Chinle of Utah and Colorado strongly suggests that other large‐diameter Chinle burrows elsewhere on the Colorado Plateau and in stratigraphically equivalent units may also be the product of crayfish activity.     

VALVE MORPHOLOGY OF SYNEDRA GOULARDI (BACILLARIOPHYCEAE)1

Specimens of Synedra goulardi Bréb. from samples taken in Costa Rica were acid cleaned and examined by light and scanning electron microscopy. This linear-lanceolate diatom displays an unusual pattern of markings in its central area which have been mistaken as striae but are actually internal costae. As is typical for members of its genus and that of many other genera in the Fragilariaceae, S. goulardi possesses non-stalked labiate processes, apical pore fields and a lack of marginal spines. There is a great deal of variability in the striae of the genus, ranging from single rows of puncta to areolate striae. Synedra goulardi has double punctate striae. The presence of fossil forms (Neogene) with single punctate striae suggest this may be a primitive condition in the genus.     

周口店直立人头骨创伤与人工切割痕迹辨析

自20世纪40年代魏敦瑞提出北京猿人（周口店直立人）可能存在“暴力争斗”和“同类残食”的观点之后,引发了一些学者和科普大众对北京猿人是否为“食人族”的争论。由于原始化石标本在第二次世界大战期间丢失,本文以保存下来的周口店（ZKD）直立人头骨原始模型和素描图为研究材料,对魏敦瑞提出的具有创伤和人工切割痕迹的5件标本（ZKD II、ZKD VI、ZKD X、ZKD XI和ZKD XII）进行辨析。结果显示：1）ZKD X、ZKD XI、ZKD XII这3件标本的头盖部,有7处可以确定为生前遭受非致死性撞击导致的局部创伤;2）ZKD VI头盖骨残片周边的及中央区域的断痕,为个体生前遭受致死性的暴力打击导致;3）ZKD II和ZKD VI顶骨位置疑似人工切割痕迹的沟槽实际上是动物啃咬或自然因素导致的,北京猿人“同类残食”的观点在本文研究中没有得到证实。北京猿人头骨的创伤痕迹都位于头盖部,以顶骨居多,其次为额骨,符合人群之间暴力冲突产生创伤的位置。     

Remarkably preserved annelid worms from the La Meseta Formation (Eocene), Seymour Island, Antarctica

Abstract: Worm tubes, which exhibit the replaced tube-lining membrane, have been collected from the lowermost Lower Eocene Acantilados Allomember of the La Meseta Formation, Seymour Island, Antarctica. The discovery represents the oldest examples of preservation of the tube-lining membrane of tube-dwelling Polychaeta in the fossil record. A new genus and species, Caprascolex antarcticus , are described. The specimens are preserved as thin coatings of amorphous iron oxide on the inner surface of the moulds interpreted to be the replaced tube-lining membrane. Examination of the rarely described tube-lining mucosoid membrane in extant polychaetes shows that the fossils are nearly identical in morphology and scale to extant forms. These fossils record in remarkable detail the morphology of the tube-lining membrane, which appears to be composed of growth bands formed as the worm constructed the tube. The tube-lining is believed to have been originally preserved as pyrite, with subsequent oxidation to iron oxide. The tube-lining membrane of worm tubes possibly is known from only one other fossil occurrence.     

Growth layers and incremental markings in hard tissues; a review of the literature and some preliminary observations about enamel structure in Paranthropus boisei

The general factors underlying the formation of growth layers and incremental markings in hard tissues are reviewed with particular reference to fossil hominid tooth enamel. The experimental and circumstantial evidence that point to a slowing of enamel matrix secretion in a daily (circadian) and near weekly (circaseptan) mode during tooth formation is also reviewed. Data from previous studies in which the number of daily increments between adjacent striae of Retzius have been recorded in primates are reviewed and new data are presented for this repeat interval in fossil hominids. The factors likely to influence the number of striae of Retzius beneath the cuspal regions of anterior teeth are outlined and the limitations of employing surface incremental features to obtain estimates for age at death of an individual are also discussed. It is concluded that there is good evidence to support the hypothesis that perikymata are near weekly incremental phenomena with a likely periodicity of 7,8 or 9 days in fossil hominids. It can also be concluded that at present, better estimates for the age at death of an individual during early phases of the growth period can be obtained from studies of perikymata than by any other non-destructive technique.     

Evidence of predation in Early Cretaceous unionoid bivalves from freshwater sediments in the Cameros Basin,Spain

Here, we present evidence of possible vertebrate predation on freshwater bivalves from the Lower Cretaceous strata of the Cameros Basin (Spain). The described collection contains the largest number of vertebrate‐inflicted shell injuries in freshwater bivalve shells yet reported in the Mesozoic continental record. Several types of shell damage on fossil shells of Protopleurobema numantina (Bivalvia: Unionoida) are described and their respective modes of formation interpreted in the context of morphological attributes of the shell injuries and the inferred tooth morphology of predators that could have inflicted such injuries. Detailed study of these bite marks shows similarities with the well‐documented injuries in the shells of marine molluscs, namely ammonoids, that have likewise been attributed to reptilian predators. The most parsimonious interpretation suggests crocodiles as the vertebrates interacting with the bivalves in the Cameros Basin. □Barremian–Aptian; bite marks; freshwater bivalves; predation; reptile; Unionoida.     

A surface microrelief on the leaves of Glossophyllum florinii (?Ginkgoales) from the Upper Triassic of Lunz,Austria

The cuticles of many extant seed plants display distinct surface microreliefs, which represent adaptations to certain habitat conditions or mechanical defences against herbivores and phytopathogenic microorganisms. Although microreliefs have variously been noted in fossil cuticles, hypotheses relating to the effectiveness of these structures in fossil plants have not been advanced to date. A surface microrelief composed of longitudinally orientated idiocuticular striae occurs on the leaves of the enigmatic Carnian (Late Triassic) gymnosperm (?ginkgophyte) Glossophyllum florinii Kräusel from the Northern Calcareous Alps of lower Austria. Most striae originate from the tips of the papillae on the stomatal subsidiary cells. The G. florinii surface microrelief may have (1) reduced leaf wettability, (2) produced or enhanced the self‐cleaning effect of the leaf, (3) prevented the formation of a water film on the leaf surface, and/or (4) mechanically stabilized the leaf. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153 , 87–95.     

Quantitative studies on some living British wetland mollusc faunas

The work described here provides a quantitative basis for die interpretation of fossil assemblages of Mollusca from wetland habitats. Wetlands were sampled for living Mollusca in East Anglia (including an intensive study at Wicken Fen) and Scotland. Within the limited geographical area of Wicken Fen, the mollusc fauna may be used to predict the vegetation and hence to reconstruct the environment. Such a relationship did not continue to hold when scattered sites throughout die East Anglian region were studied. However, the relict nature of these fens should be taken into account. In die central Highlands of Scotland, a better correlation was found between mollusc fauna and flora, though this was inadequate for reconstruction of details of the vegetation. Within the context of wetland, the presence of certain rare species of narrow ecological tolerance is considered the best available measure for the reconstruction of die environment from molluscan assemblages, but their absence is meaningless. Quantitative studies of assemblages of the common species may still prove to be of value at the coarser level of discrimination between wetland, grassland and woodland, but the data are not available. Numerous quantitative studies of fossil assemblages of Mollusca from Quaternary sediments have been made and the results have been interpreted to indicate past environmental and climatic conditions. In previous studies, common species have been placed into ecological categories based on qualitative observations of the occurrence of Mollusca in modern environments, and fossil assemblages have then been interpreted as being formed by transport and accumulation from a variety of different habitats. This may be the case, but equally studies of the living assemblages have shown that the structural complexity of a single habitat may lead to species of very different ecological groups living within the same area of ground. It is simpler to interpret certain fossil assemblages as having been formed in situ in structurally diverse environments, rather than invoking mixing from different environments.     

Unraveling hominin behavior at another anthropogenic site from Olduvai Gorge (Tanzania): new archaeological and taphonomic research at BK, Upper Bed II

New archaeological excavations and research at BK, Upper Bed II (Olduvai Gorge, Tanzania) have yielded a rich and unbiased collection of fossil bones. These new excavations show that BK is a stratified deposit formed in a riverine setting close to an alluvial plain. The present taphonomic study reveals the second-largest collection of hominin-modified bones from Olduvai, with abundant cut marks found on most of the anatomical areas preserved. Meat and marrow exploitation is reconstructed using the taphonomic signatures left on the bones by hominins. Highly cut-marked long limb shafts, especially those of upper limb bones, suggest that hominins at BK were actively engaged in acquiring small and middle-sized animals using strategies other than passive scavenging. The exploitation of large-sized game (Pelorovis) by Lower Pleistocene hominins, as suggested by previous researchers, is supported by the present study.     

Age and growth rate determinations of an intertidal bivalve, Phacosoma japonicum, using internal shell increments

A venerid bivalve Phacosoma japonicum (Reeve) occurring commonly in the Japanese coastal area preserves periodic growth lines in the shell cross-section. Long-term shell growth patterns of this species have been traced for many individuals on the intertidal flat of the Seto Inland Sea, west Japan. Sclerochronological analysis of these individuals and specimens collected monthly shows that several growth cessation marks within their shells are formed during the winter of each year prior to spawning. Hence the marks were used for age and growth rate determinations. As large individuals showed little shell growth for more than two years after the formation of 7 or 8 annual increments, this species probably has a lifespan of more than ten years. Shell growth patterns of this species based on annual increments can be accurately approximated by a von Bertalanffy curve. The number of microgrowth increments formed during a year tends to decrease with age, although it varies markedly among specimens of the same age. Furthermore, even in summer during rapid shell growth, the microgrowth increments do not represent daily and/or sub-daily tidal rhythms in many specimens. The results of this study and those by several authors strongly suggest that the annual increments are the key for age and growth rate determinations of both living and fossil bivalve species.     

Über Schalenabschliffe beiCardium edule aus der Königsbucht bei List auf Sylt

Two communities of the recent bivalveCardium edule L. were collected in the tidal flats near List on the island of Sylt (Southern North Sea). The cockles were examined for abrasion marks on the surfaces of their valves arising from various causes. One important group of abrasions reveals traction marks restricted to the beak region, caused exclusively by valve movements. Another group is characterized by marks due to shell abrasions on the sea bed. The various types of abrasion marks have been studied in living cockles, both in the sea and in laboratory containers, and the results compared with those obtained on dead ones still connected by the ligament. In the sea, livingCardium edule were studied via Scuba-observations. Traction marks on the umbo support the conclusion that living cockles sometimes rest on their dorsal shell area. Holes in the convex umbo, umbonal facets, originate after death in situ or through shiftings to and fro on the sea bed, and also as a result of chemical or biological processes. The method applied and the criteria of shell abrasions employed are considered acceptable approaches to the interpretation of functional morphology and behaviour in fossil molluscs.     

Additional human remains from Blombos Cave, South Africa: (1999-2000 excavations)

The uppermost Middle Stone Age (MSA) layers at Blombos Cave contain high densities of Still Bay bifacial points. Information from other regional sites places the Still Bay prior to the Howiesons Poort industry, which has been dated at 65-70 ka. The Blombos Cave MSA strata have yielded nine human teeth or dental fragments. Four that were recovered during the 1997-1998 excavations have been published elsewhere. The remaining five were discovered during the 1999-2000 field seasons; these are described here. Three of the new specimens are deciduous teeth, and two are permanent premolar and molar crown fragments. The entire dental sample probably represents at least five and as many as seven individuals. The deciduous teeth from the upper MSA levels are likely to have been exfoliated in the cave. One deciduous tooth and the permanent tooth fragments from the lower MSA levels probably represent three individuals who died in or near the cave. The Blombos Cave premolars preserve horizontal circum-cervical striae suggestive of palliative tooth pick use. Approximately half of the permanent and deciduous crown diameters exceed those of recent Africans; for the remainder, the fossil values fall among modern African sample means. The Blombos Cave tooth crowns tend to be smaller than the majority of penecontemporaneous Neandertal teeth. The morphology of the Blombos Cave di is comparable to MSA homologues from the nearby, and presumably somewhat younger site of Die Kelders Cave 1.     

A new trace fossil from the Middle Cambrian of the Grand Canyon, Arizona, USA

An unusual trace fossil from the Middle Cambrian Bright Angel Shale Formation of the Grand Canyon, Arizona, consisting of two rows of biserially opposed circular or oval depressions, with alternating symmetry, is described as Bicavichnites martini ichnogen. et ichnosp. nov. While specimens of this trace may represent the surface expression of a complex treptichnid-like burrow system, it is more likely that they are the walking traces of a bilaterally symmetrical benthic animal. The large variation in external width within the trackways is inconsistent with an arthropod producer. The trackway morphology and presence of limb spur marks suggest that the trace maker may have been a lobopodian, a Cambrian relative of modern onychophorans.     

Meridian is a Three-Dimensional Network from Bio-Electromagnetic Radiation Interference: An Interference Hypothesis of Meridian

An electromagnetic radiation field within a biological organism is characterized by non-local interference. The interfering beams form a unitary tridimensional network with beams of varying intensity, also called striae, which are distributed on the organism surface. These striae are equivalent to semi-reflectors. The striae carry bio-information of corresponding organs and, thus, integrate all tissues, and organs of the organism. The longitudinal striae are classified as channels, while the transverse striae are collaterals. The acupoints are seen as the points where electromagnetic interfering striae intersect or converge. This hypothesis builds a foundation to understand the traditional Chinese medicine, including acupuncture, from the perspective of scientific knowledge.     

Enamel thickness and development in a third permanent molar of Gigantopithecus blacki

A ground section was prepared from a lower right M3 attributed to Gigantopithecus blacki as close as possible to axial plane of the mesial cusps. Daily cross striations were imaged, measured and counted in each cusp using polarised light microscopy. Long-period striae of Retzius were counted in the lateral enamel and their periodicity determined from counts and measurements of daily cross striations between adjacent striae. Cross striation spacings in the cusps were between 3.8 microm at the enamel dentine junction and 6 microm close to the enamel surface. Cuspal enamel formation times were long (800 days in the protoconid and 620 days in the metaconid). Linear enamel thickness was as much as 3.75 mm in the protoconid. There were 63 and 61 long-period striae of Retzius in the mesial aspects of the lateral enamel and the periodicity was 11 days. Lateral enamel formation took 1493 and 1291 days and when summed with cuspal enamel formation times totalled 4 years in the protoconid and 3.5 in the metaconid. Relative enamel thickness was 23, calculated through the mesial cusps. This falls short of that in the so-called 'thick hyper-thick' enamel described in 'robust' australopithecines to which Gigantopithecus blacki has previously been compared in both its dental and mandibular morphology. With respect to enamel thickness, therefore, Gigantopithecus blacki falls squarely among an increasingly large number of Miocene hominoids that can all be described as having 'thick enamel'.     

Brief communication: cutmarks on a plio-pleistocene hominid from Sterkfontein, South Africa

Cutmarks inflicted by a stone tool were observed on the right maxilla of Stw 53, an early hominid partial skull from Sterkfontein "Member 5" (South Africa). The morphology of the marks, their anatomical placement, and the lack of random striae on the specimen all support an interpretation of this linear damage as cutmarks. The location of the marks on the lateral aspect of the zygomatic process of the maxilla is consistent with that expected from slicing through the masseter muscle, presumably to remove the mandible from the cranium. Although radioisotopic dates are not available and relative faunal dating of the deposit from which Stw 53 derives is problematic, the morphology of the hominid skull suggests a Plio-Pleistocene age for the specimen. This therefore constitutes the earliest unambiguous evidence that hominids disarticulated the remains of one another.