Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora,northeast Spain

McNamara, M.E., Orr, P.J., Manzocchi, T., Alcalá, L., Anadón, P. & Peñalver, E. 2011: Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora, northeast Spain. Lethaia, Vol. 45, pp. 210–226. The middle Miocene Rubielos de Mora Konservat‐Lagerstätte of northeast Spain is hosted within profundal, finely laminated, lacustrine mudstones. The diverse biota includes abundant salamanders. Most individuals died during separate episodes and sank rapidly postmortem. Specimens are typically preserved in dorso‐ventral aspect, the most hydrodynamically stable orientation. The near‐cylindrical morphology of the body, however, allowed some carcasses to settle in or subsequently re‐orientate into, lateral orientations. Loss of skeletal elements (i.e. reduced completeness) reflects their location within the body and followed a distal to proximal trend. Two stages are identified: initial loss of a small number of phalanges, followed by loss of more proximal limb bones plus additional phalanges. Disarticulation is more complex: it occurred via several mechanisms (notably, abdominal rupture and re‐orientation of part of the body and limbs during decay) and shows no consistent pattern among specimens. The physical taphonomy of the salamanders is controlled predominantly by intrinsic biological factors, i.e. the geometry of the body and of individual skeletal elements, the orientation, inherent strength and location of specific joints and the extent to which soft tissues, particularly the skin, persist during decay. These biological factors probably control patterns of physical taphonomy of other fossil tetrapods with a similar skeletal configuration. □Articulation, completeness, Konservat‐Lagerstätten, orientation, quantitative taphonomy, salamanders.     

Exceptionally preserved lacustrine ostracods from the Middle Miocene of Antarctica: implications for high-latitude palaeoenvironment at 77 degrees south

A newly discovered Konservat-Lagerstätte from the Middle Miocene of the western Olympus Range, Dry Valleys, Antarctica, yields cypridoidean ostracods complete with preserved body and appendages. This is the first record of three-dimensionally fossilized animal soft tissues from the continent. The ostracods are preserved in goethite, secondary after pyrite, representing a novel mode of exceptional preservation. They signal a high-latitude (greater than 77° south) lake setting (Palaeolake Boreas) viable for benthic animal colonization prior to 14 Myr ago. Their presence supports the notion of warmer, tundra-like environmental conditions persisting in the Dry Valleys until the Middle Miocene.     

内蒙古大庙中新世小哺乳动物化石埋藏学研究

捕食是小哺乳动物死亡最常见的原因,也导致被捕食动物遗骸发生明显改变.动物死亡后的风化、踩踏、搬运等过程也会改变动物的骨骼并影响到化石组合的形成.本文研究了内蒙古大庙三个中新世化石地点,时代从早中新世到晚中新世早期(约21～11.6 Ma).通过分析各小哺乳动物化石组合的沉积背景以及埋藏学特征识别化石埋藏的主要成因.结果显示出捕食是三个地点小哺乳动物化石埋藏的基本成因,而在两个年轻的地点中也有流水搬运与可能的踩踏因素的叠加.三个地点可能存在不一样的捕食者:早中新世地点以猫头鹰捕食为主,中、晚中新世地点则以日间活动的鸟类或哺乳类为主要捕食者.研究还显示小哺乳动物的系统发掘是可行的,在一定程度上可以减少采样过程中产生的破坏.     

Exceptionally well‐preserved vegetal remains from the Upper Cretaceous of ‘Lo Hueco’, Cuenca,Spain

Vegetal remains are considered labile structures that quickly become decayed in ecosystems. However, certain lignified tissues (woody plants) can largely resist decomposition, becoming sometimes exceptionally well preserved. At the Upper Cretaceous site of ‘Lo Hueco’ (Cuenca, Spain), those woody remains (trunks and branches) with resinous material in the inner tracheids and parenchyma cells that were buried rapidly under anoxic conditions experienced a low degree of maturation, becoming exceptionally well preserved. Those woody remains deposited under oxic conditions (sub‐aerial or sub‐aquatic exposure) were more intensely biodegraded and subsequently carbonified, partially or completely mineralized in gypsum and covered by a ferruginous crust. These two modes of preservation are scarce, with silicification or carbonification processes much more common, and both can be considered as ‘exceptional preservation’. Other vegetal remains, such as carbonified leaves, stems and roots, were collected in the site. The different modes of preservation depend directly on: depositional micro‐environment (sandy distributary channel, muddy flood plain); and type (trunk, branch, stem, leave, root) and state (presence or absence of resinous material) of the material. The great abundance and diversity of fossils in ‘Lo Hueco’ identify it as Konzentrat‐Lagerstätten, sequentially formed by alternated events of flooding and drying depositional events, but the exceptional quality and rarity of determinate vegetal macroremains preservation suggest that certain deposits of this site can be considered as conservation deposits.     

内蒙古大庙中新世小哺乳动物化石埋藏学研究（英文）

捕食是小哺乳动物死亡最常见的原因,也导致被捕食动物遗骸发生明显改变。动物死亡后的风化、踩踏、搬运等过程也会改变动物的骨骼并影响到化石组合的形成。本文研究了内蒙古大庙三个中新世化石地点,时代从早中新世到晚中新世早期(约21~11.6 Ma)。通过分析各小哺乳动物化石组合的沉积背景以及埋藏学特征识别化石埋藏的主要成因。结果显示出捕食是三个地点小哺乳动物化石埋藏的基本成因,而在两个年轻的地点中也有流水搬运与可能的踩踏因素的叠加。三个地点可能存在不一样的捕食者:早中新世地点以猫头鹰捕食为主,中、晚中新世地点则以日间活动的鸟类或哺乳类为主要捕食者。研究还显示小哺乳动物的系统发掘是可行的,在一定程度上可以减少采样过程中产生的破坏。     

Biostratigraphy and biochronology of the Late Miocene of central Argentina: Evidence from rodents and taphonomy

Biostratigraphy and biochronology of the Late Miocene of central Argentina is analyzed through evolutionary patterns of octodontoid rodents. The studied faunas were found in continental sediments assigned to the Cerro Azul and Saldungaray formations (La Pampa and Buenos Aires provinces, respectively). Taphonomic attributes of recovered mammals, linked mostly to the development of paleosols or to predators’ activities, constraint the deposition lapse to short intervals. A biostratigraphic scheme based mainly on the anagenetic pattern of change in the octodontoid rodent lineage Chasichimys-Xenodontomys is proposed. Since there is no stratigraphic superposition among the studied levels, relationships among deposits are established through the polarity evidenced by the stage of evolution of chronomorphs of this lineage. Five new biozones for the Late Miocene of central Argentina are recognized. Evidence of other anagenetic sequences, and general trends of increasing hypsodonty in octodontoids, support this proposal. The results enhance the value of the “stage of evolution” concept as a correlation tool in biostratigraphic and biochronologic studies, mainly when applied through phyletic sequences.     

A new Late Jurassic turtle from Spain: phylogenetic implications,taphonomy and palaeoecology

Abstract: The Jurassic was an important period in the evolution of Testudinata and encompasses the origin of many clades, and this is especially true of Jurassic turtles from Western Europe. A new genus and species of Late Jurassic turtle, Hispaniachelys prebetica gen. et sp. nov. from the upper Oxfordian of the Prebetic (Southern Spain), is described on the basis of postcranial material. The specimen is the only known tetrapod from the Mesozoic of the Prebetic and the oldest turtle from southern Europe. A mosaic of characters indicates this is a new genus: it displays basal features including dorsal epiplastral processes/reduced cleithra, no medial contact of the extragulars and a long first thoracic rib, alongside derived characters including an absence of mesoplastra and the vertebral 3/4 sulcus crossing neural 5. The phylogenetic position of the new taxon is hard to resolve, and it might be either a paracryptodire or a basal testudine, but it is distinct from Plesiochelys. A complex taphonomic history is shown by a range of overlying grazing traces and bioerosion on the carapace. The carapace was subsequently overturned and buried ventrally up, terminating grazing activity, and was then bored by sponges before final burial. Scanning electron microscopy reveals phosphatic microspheroids associated with bacterial decay in the vascular cavities of the cancellous bone, suggesting the carapace may have acted as a closed microenvironment in which decay‐derived authigenic minerals formed.     

Vertebrate taphonomy in loess-palaeosol deposits: A case study from the late Miocene of central Argentina

This paper deals with the taphonomic analysis of the late Miocene bone assemblage from the Cerro Azul Formation at Telén (La Pampa Province, Argentina). The faunal assemblage was assigned to the Huayquerian mammal age (late Miocene). The fossiliferous section shows a homogeneous lithology, and is interpreted as a loess deposit with two similar and slightly developed palaeosols, classified as calcic vertisols. The studied sample comprises 5598 remains anatomically and taxonomically determined. They were collected from an area of about 48,000 m², appearing randomly distributed through the section and with low density. Most remains are small- to very small-sized, disarticulated, and very fragmented. Different taphonomical histories are inferred for microvertebrates and macromammals. The microvertebrate assemblage is interpreted as the result of predator activities. After a brief period of pre-burial exposure, remains were dispersed from the original depositional area. On the other hand, a natural and gradual death process is envisaged for macromammals, followed by a long period of exposure to weathering and dispersal by physical agents. Remains of both groups, once buried, suffered the diagenetic processes of the host rock. Consequently, the fossil assemblage from Telén would represent a condensed assemblage corresponding to two distinct time spans, i.e., the accumulation of microvertebrates took place in a short time interval whereas that of macromammals occurred over a longer period, coincident with the development of both soils.     

A new short-snouted shrew from the Miocene of Spain

A new Miocene shrew from east Central Spain is described. The new form, named Turiasorex pierremeini nov. gen., nov. sp., was found in 13-10–Ma old sediments of the Calatayud-Daroca and Teruel basins. It is characterized by an extreme dental morphology consisting of elements with low length-width ratios, implying a relatively short snout. Such an adaptation could point to a hypogeal life style – using burrows made by other mammals – with a non-standard shrew diet consisting not only of insects, but also of earthworms and possibly small vertebrates such as lizards.     

New Ichnospecies of Cardioichnus from the Miocene of the Guadalquivir Basin,Huelva, Spain

A new ichnospecies of Cardioichnus, Cardioichnus reniformis isp. nov., is documented and described from marine strata of the Late Miocene of southwestern Spain. It is a bilobate resting trace with a heart‐shaped outline and is related to the work of a wedge‐shaped irregular echinoid of the spatangoid group.     

Morphology and ontogeny of Cretaceous ostracods with preserved appendages from Brazil

The Lower Cretaceous ostracod Pattersoncypris micropapillosa Bate is redescribed, and Reconcavona sp. indet. with appendages preserved is described for the first time. The morphology of the carapace and especially of the appendages of P. micropapillosa is compared in detail with that of the Recent Cyprididae Eucypris virens , which demonstrates that there are substantial similarities. In addition to the adults of P. micropapillosa , a number of juveniles have also been recovered and described, and these are compared with the juveniles of E. virens . The ontogenetic development of P. micropapillosa is shown to be very similar to that of Recent Cyprididae. This has highlighted that this group of ostracods has changed very little over the last 100 My. P. micropapillosa is tentatively placed in the subfamily Cyprinotinae, based on features of the upper lip. As the morphology of the appendages and the ontogeny of P. micropapillosa are very similar to those of Recent forms, it is postulated that the function of the limbs and lifestyle were also similar, i.e. it was nektobenthic and an opportunistic detritus feeder.     

Exceptionally preserved conulariids and an edrioasteroid from the Hunsrück Slate (Lower Devonian,SW Germany)

Abstract: Nineteen partial specimens of Conularia sp., together with an articulated agelacrinitid edrioasteroid and several discinid brachiopods, occur in close association with a probable biological substrate on a small slab of silty Hunsrück Slate (Lower Devonian, Emsian) from Bundenbach, Germany. Most of the conulariids occur in V‐like pairs or in a single cluster of 12 specimens arranged in a fan‐like radial pattern. Together with the edrioasteroid and (possibly) brachiopods, the conulariids probably were attached to the substrate in life and then were buried and possibly killed by a single influx of silty mud. The apertural end of many of the conulariids is partially covered by inwardly folded short lappets, which may have closed in response to rapid (but gentle) burial. Rock matrix in the apertural region of the peridermal cavity of nearly all of the conulariids exhibits irregular, variably dense concentrations of pyrite. The concentrations occur almost exclusively within the conulariids, where they probably formed as a result of the decay of retracted conulariid soft parts. Although the concentrations lack clearly defined anatomical features that can be unambiguously homologized with particular anatomical structures of any extant taxon, their form and distribution within the conulariids are consistent with the hypothesis that conulariids were polypoid scyphozoans.     

A new elasmotheriine (Mammalia,Rhinocerotidae) from the Early Miocene of Spain

A new species of Hispanotherium from the Early Miocene of Spain is named. Its phylogenetic relationships within Elasmotheriina are discussed owing to a cladistic analysis. H. grimmi Heissig, 1974 and H. beonense Antoine, 1997 are consequently integrated in the genus Hispanotherium, together with the type species H. matritense and the new species, which differs from other ones by several dental and postcranial features. The westward dispersal of the Elasmotheriina from Asia toward Western Europe during the Early Miocene is hypothesized. To cite this article: P.-O. Antoine et al., C. R. Palevol 1 (2002) 19–26.     

Coral biostromes of the Middle Jurassic from the Subbetic (Betic Cordillera,southern Spain): facies,coral taxonomy,taphonomy, and palaeoecology

Coral biostromes from the Camarena Formation (External Subbetic, Betic Cordillera) are reviewed under palaeoecologic, taphonomic, and palaeontologic aspects. The biostromes are dominated by phaceloid forms and are characterized by a typical shallow-marine microencruster assemblage with photophilic microencrusters and scarce microbial crusts. The abundance of stylinid corals and light-dependant microencrusters suggests oligotrophic conditions. Coral colonies were located among oolitic shoals that were unfavorable for coral growth. The corals were developed in phases without oolitic production alternating with phases of oolitic production, forming metric-scale sequences. A relative sea-level fall would have reduced the ooidal production and led to the deposition of thin layers of micritic facies in intertidal areas. The cementation and hardening of the bottom resulted in a hardground that was colonized by corals after a subsequent relative sea-level rise. The progressive increase of the energetic conditions induced an increasing production of ooids and the migration of oolitic shoals, which covered and finished the coral biostromes. Repetition of this process gave rise to sequences reflecting small pulses of oscillations in the relative sea level.     

Quantitative reconstruction of palaeoclimate from the Middle Miocene Shanwang flora, eastern China

The fossil leaf flora from the Shanwang Formation, Linqu County, Shandong Province, eastern China, is diverse, abundant, well preserved and discretely spaced, all of which make it suitable for the recognition and application of leaf physiognomic characters. This article is the first study of Chinese Tertiary floras using the CLAMP (Climate Leaf Analysis Multivariate Program) approach. Numerous bedding planes yield leaf assemblages through over 20 m thickness of diatomaceous shales within the Middle Miocene Shanwang Formation. The diatomaceous shales, containing abundant fossils, have been divided into 19 units. A working platform (3×3 m) in the Diatomite Quarry of Shanwang was studied for about 3 months in 1998 and as many fossils as possible were recorded layer by layer. This collecting method, used for the first time in the history of Shanwang research, enabled us to record the presence or absence of megafossils in distinct units so that we could investigate leaf physiognomic characteristics and palaeoclimate for each time interval. Leaf fossils from six units (5, 6, 7, 13, 15 and 16) have been used to estimate palaeoclimate parameters of the Shanwang area using the CLAMP 3B dataset. The predicted climate is that of a lakeside setting, at over 1000 m above sea level and within the 17–15-Ma time interval. Meteorological factors have been estimated using the CLAMP approach, including mean annual temperature (MAT; 9.5–11.2°C), warmest month mean temperature (20.2–22.5°C), growing season length (5.9–6.8 months), mean growing season precipitation (83–165 cm) and relative humidity (73–79%). MAT estimates from leaf margin analysis (LMA) range from 12.5 to 15.2°C, which are a maximum of 4° higher than those from our CLAMP analyses and from previous results of LMA studies of the Shanwang flora (10–13°C). Nearest living relatives (NLR) of other biota (pollen, fish, insects, diatoms, microthyriaceous fungi, etc.) indicate warm and moist temperate to subtropical conditions in the Shanwang area during the Miocene. CLAMP predictions are similar to the climate predicted from NLRs although the MAT prediction is a few degrees cooler. The fact that the Shanwang leaf flora is from a lacustrine sequence may have biased the CLAMP analysis towards cooler (and possibly wetter) climates. The modern Yangtze River valley is a reasonable environmental analogue for the Shanwang Middle Miocene, though Shanwang may have had cooler summers, cooler MAT and less seasonality in rainfall. The climate was essentially constant during deposition of the sequence studied, with possible minor variations in precipitation.     

Rodents and insectivores from the late Miocene of Romerales (Fortuna Basin,Southern Spain)

Abstract

The Neogene Fortuna Basin (Murcia Region, SE Spain) is rich in microvertebrate sites. Its continental sections include localities extended from the middle Turolian (MN12) to the early Ruscinian (MN14). However, there are few works dealing with the taxonomy of these fossil assemblages. In this paper we provide a complete taxonomic study of the rodents and insectivores from three levels (ROM-2B, ROM-2C and ROM-3A) within the Romerales section. We infer a late Turolian age (late Messinian) for these levels, among which the richest and most diverse level is ROM-C, including at least 11 different taxa. In addition, the paleoecological analysis of these fossil assemblages suggests the dominance of open herbaceous meadows under temperate climate during the formation of these sites, with a slight decrease in temperature and humidity from ROM-2B to ROM-2C.     

Architectural complexity of marine crustacean burrows: unusual helical trace fossils from the Miocene of Mallorca,Spain

Gibert, J.M. de, Mas, G. & Ekdale, A.A. 2012: Architectural complexity of marine crustacean burrows: unusual helical trace fossils from the Miocene of Mallorca, Spain. Lethaia, Vol. 45, pp. 574–585. Unusual helical trace fossils occur in Tortonian shelfal calcarenites in the island of Mallorca. Their morphology may be either simple (ichnogenus Gyrolithes) or, more commonly, consist of two concentric helical burrows (ichnogenus Lapispira). They bear a very characteristic pelleted lining and are associated and probably connected to Thalassinoides and Ophiomorpha burrow systems very abundant in the same unit. These features allow the interpretation that the tracemaker was a thalassinidean shrimp. The complex and compound nature of these trace fossils is comparable to that seen in other modern and fossil crustacean burrow systems, and it reflects the behavioural plasticity of the architects. □Trace fossils, ichnology, ichnofabrics, crustacean burrows, Miocene, shallow marine, Lapispira.     

Advances in Cambrian stratigraphy and paleontology: Integrating correlation techniques, paleobiology, taphonomy and paleoenvironmental reconstruction

Papers resulting from the Fourth International Symposium on the Cambrian System, held in Nanjing, China, in 2005 cover three major aspects of geology and paleontology: (1) the developing global standard for Cambrian chronostratigraphy or regional correlation schemes; (2) regional lithostratigraphy, sedimentology and paleoenvironments; (3) organismal paleobiology, phylogenetic affinities and taphonomy.A generalized curve of carbon isotopes (δ¹³C) through the Cambrian suggests a relationship between major biotic events, sea level history and the development of deposits of exceptional preservation (Lagerstätten). Recognition of this relationship increases the importance of the δ¹³C profile as a tool for intercontinental and intracontinental correlation. Significant δ¹³C excursions in the Cambrian are: BACE (negative excursion at the base of the Cambrian System); ZHUCE (positive excursion in the lower part of Stage 2); SHICE (negative excursion in the middle part of Stage 2); CARE (positive excursion near the base of Stage 3); MICE (positive excursion in the lower part of Stage 4); AECE (negative excursion in the middle part of Stage 4); ROECE (negative excursion near the base of Stage 5); DICE (negative excursion beginning near the base of the Drumian Stage); SPICE (positive excursion beginning at the base of the Paibian Stage); TOCE (negative excursion near the top of Stage 10). All acronyms other than SPICE are newly proposed.