Miocene Beds Research Articles

New reports of decapod Portunus monspeliensis A. Milne Edwards, 1860 from Miocene beds of eastern Slovenia with notes on palaeoecology and palaeobiogeography

New reports of decapod Portunus monspeliensis A. Milne Edwards, 1860 from Miocene beds of eastern Slovenia with notes on palaeoecology and palaeobiogeography

Fruits and wood of Parinari from the early Miocene of Panama and the fossil record of Chrysobalanaceae.

Chrysobalanaceae are woody plants with over 500 species in 20 genera. They are among the most common trees in tropical forests, but a sparse fossil record has limited our ability to test evolutionary and biogeographic hypotheses, and several previous reports of Chrysobalanaceae megafossils are doubtful. We prepared fossil endocarps and wood collected from the lower Miocene beds along the Panama Canal using the cellulose acetate peel technique and examined them using light microscopy. We compared the fossil endocarps with previously published fossils and with fruits from herbarium specimens. We compared the fossil wood with photographs and descriptions of extant species. Parinari endocarps can be distinguished from other genera within Chrysobalanaceae by a suite of features, i.e., thick wall, a secondary septum, seminal cavities lined with dense, woolly trichomes, and two ovate to lingulate basal germination plugs. Fossil endocarps from the Cucaracha, Culebra, and La Boca Formations confirm that Parinari was present in the neotropics by the early Miocene. The earliest unequivocal evidence of crown-group Chrysobalanaceae is late Oligocene-early Miocene, and the genus Parinari was distinct by at least 19 million years ago. Parinari and other Chrysobalanaceae likely reached the neotropics via long-distance dispersal rather than vicariance. The presence of Parinari in the Cucaracha flora supports the interpretation of a riparian, moist tropical forest environment. Parinari was probably a canopy-dominant tree in the Cucaracha forest and took advantage of the local megafauna for seed dispersal.

New reports of crab Styrioplax exiguusGlaessner, 1928 (Decapoda, Brachyura) from Miocene beds near Maribor, Slovenia

New reports of crab Styrioplax exiguusGlaessner, 1928 (Decapoda, Brachyura) from Miocene beds near Maribor, Slovenia

A New Cerithioidean GenusMegistocerithium(Gastropoda; Mollusca) from the Miocene of Southeast Asia: A Possible Relict of Mesozoic “Eustomatidae”

Abstract. Based upon large cerithiform gastropod specimens from the middle Miocene beds of Java, Indonesia and the Philippines, a new genus and new species, Megistocerithium magoi, is described herein. Ten fragmentary specimens from the lower and upper Miocene beds of the Philippines are tentatively referred to this species. M. magoi Kase sp. nov. is amongst the largest fossil cerithioidean gastropods (except for Turritellidae). It was a dweller in intertidal sandy mudflats, probably in close proximity to mangrove forests. No species considered to be congeneric with this species have been found in the Cenozoic. On the other hand, M. magoi Kase gen. et sp. nov. shares apertural characters with the Middle Jurassic species Eustoma tuberculosa, the type species of a genus belonging to the yet to be well-recognized family Eustomatidae. M. magoi Kase gen.et sp. nov. is possibly a relict of the Mesozoic Eustomatidae. It is assumed to have been a grazer on mangrove litter like the potamidid genera Terebralia and ...

The first record of Deinotherium (Proboscidea, Mammalia) in the Miocene of Adygea.

The data on an isolated upper tooth (P4) of Deinotherium sp. from the Late Miocene beds of the Maikop 1 locality (Maikop, Republic of Adygea) are reported. This is the first record of Deinotherium from the Upper Miocene of Russia. The tooth crown of P4 is similar in size to D. proavum Eichwald, 1831 (= D. gigantissimum Stefanescu, 1892).

Morphology of the forelimb of Psilopterus bachmanni (Aves, Cariamiformes) (Early Miocene of Patagonia)

Psilopterines are the smallest and most gracile predatory birds belonging to the large terrestrial Phorusrhacidae, which were abundant during the South American Tertiary. Two taxa are recognized from the Santacrucian (late Early Miocene) beds of Argentinian Patagonia: Psilopterus lemoinei and Psilopterus bachmanni. Although the first species was recently redescribed and is well known, in the case of P. bachmanni, the smaller of the two, the forelimb skeleton was virtually unknown until recently. The fossils described herein come from the coast of Santa Cruz Province, and were recovered from the middle levels of the Estancia La Costa Member, Santa Cruz Formation. The specimen includes associated bones of both forelimbs and a fragmentary furcula. The manus of this species, previously unknown, is described here for the first time: the os carpi ulnare and radiale are very stout bones, the carpometacarpus has processi extensorius and alularis very marked and stout and the os metacarpale majus and phalanges digiti majoris are very robust, and the phalanx digiti minoris is flattened. It has been proposed that some species belonging to Psilopterus were able to fly in a clumsy manner. While this work is not intended to certify this condition through complex models, some considerations of the paleobiology of P. bachmanni based on manus movement capabilities and body mass are presented. It seems plausible that P. bachmanni would have had both cursorial and flying capabilities. The information provided here represents an effort to discuss features previously unknown in phorusrhacids and to provide new data that may be useful in future systematic, morpho-functional and evolutionary studies.

Some rare fossils from Slovenske gorice, Slovenia

This contribution presents remains of very rare bivalves from Miocene beds of Meljski hrib, Vukovski dol and surroundings of Lenart in Slovenske gorice. Determined were bivalves Solemya doderleini (Mayer, 1861), Lentipecten denudatus (Reuss, 1867), Limaria labani (Meznerics, 1936), Cubitostrea digitalina (Dubois, 1831) and Ostrea lamellosa Brocchi, 1814. In northeastern borders of Maribor were found in sandy and micaceous marlstones of Meljski hrib next to bivalves also remains of ophiuroids. The studied inventory of mollusks and echinoderms belongs to Miocene beds of the southern part of the Styrian basin of the Central Paratethys.

Fish remains from Miocene beds of Višnja vas near Vojnik, Slovenia

This paper discusses fossil teeth of sharks (Elasmobranchii, Neoselachii) and porgies (Teleostei, Sparidae) from the Miocene glauconite sandstones of Višnja vas near Vojnik. The remains of fish teeth, mostly tooth crowns belong to cartilaginous fishes of the genera Notorynchus, Carcharias, Carcharoides, Isurus and Cosmopolitodus and to a bony fish genus Pagrus.

The brachiopod Lingula from the Middle Miocene – Badenian beds of Slovenia

The article discusses the first find of an inarticulate brachiopod in Slovenia. The fossil was discovered in Miocene beds in Badenian sandy and marly limestones outcropping in the Plesko quarry near Trbovlje. It belongs to the species Lingula dregeri Andreae, 1893.

The first known fossil record of pygmy pipehorses (Teleostei: Syngnathidae: Hippocampinae) from the Miocene Coprolitic Horizon, Tunjice Hills, Slovenia

The first known fossil record of pygmy pipehorses is described. The fossils were collected in the Middle Miocene (Sarmatian) beds of the Coprolitic Horizon in the Tunjice Hills, Slovenia. They belong to a new genus and species Hippotropiscis frenki, which was similar to the extant representatives of Acentronura, Amphelikturus, Idiotropiscis, and Kyonemichthys genera. Hippotropiscis frenki lived among seagrasses and macroalgae and probably also on a mud and silt bottom in the temperate shallow coastal waters of the western part of the Central Paratethys Sea. The high coronet on the head, the ridge system and the high angle at which the head is angled ventrad indicate that Hippotropiscis is most related to Idiotropiscis and Hippocampus (seahorses) and probably separated from the main seahorse lineage later than Idiotropiscis.

Oldest record of the Great White Shark (Lamnidae, Carcharodon; Miocene) in the Southern Atlantic

Lamnid teeth close to but more plesiomorph than Carcharodon carcharias were collected in the late Miocene beds of the Paraná Formation in the central eastern Argentina. We propose, as other authors, that some species formerly assigned to Isurus or to Cosmopolitodus should be included in Carcharodon. Some workers suggested that C. carcharias originated by phyletic evolution in the Pacific basin. The teeth from Paraná could pertain to a new species of Carcharodon already known from Perú. In contrast with the Pacific basin, Carcharodon sp. was sympatric with the wide toothed species Carcharodon plicatilis in central Argentina. This is the oldest record of Carcharodon in the southern Atlantic.

A Miocene Continental Basin associated with the back thrusting of the Eastern Sierras Pampeanas in the Santa Maria Valley, Northwestern Argentina

Geological research in the Santa Maria Valley began more than one hundred years ago. Most studies have focused on stratigraphic aspects of the valley. The present study addresses the structures of the Miocene sequences in the Santa Maria Valley, on which there has previously been a lack of information. The eastern border of the northern Sierras Pampeanas (northwestern Argentina), is dominated by NNE-SSW faults that form a back-thrust front extending for more than 800 km. Intermontane basins filled with Neogene beds are associated with this back-thrusting belt, one of which is the Santa Maria Valley, which makes up the southernmost portion of the Calchaqui Valley. The Santa Maria Valley was formed by two superposed tectonic events. The first event, during a phase of the Miocene (ca. 13-5 Ma), was an extension and volcanism during which a 5000-m-thick sedimentary succession of non-marine beds accumulated, lying directly on the crystalline Proterozoic basement. A compressional event followed, causing folding and thrusting. This contraction resulted in antiforms of sedimentary beds and the cry - stalline basement, and large basement-cored antiforms were formed, each of which corresponds to a range. The Cumbres Calchaquies and Aconquija Range antiforms, at the eastern border of the valley, were backthrust over the Miocene beds filling the valley. These two structures are separated by the Amaicha Valley, which coincides with a regional, oblique, NW-SE-trending fault showing strike-slip displacement. The Miocene beds filling the valley show overlappin relationships to the east and west; to the east, the beds overlap a structural high that coincides with a sedimentation-free area located east of the Santa Maria Valley. The Miocene sedimentation took place over an irregular floor with offsets delimited by normal faults. The most significant step strikes NW-SE and x approximately coincides with the fault trending along the Amaicha Valley.

Active seismic and passive microtremor HVSR for assessing site effects in Jammu city, NW Himalaya, India—A case study

Abstract 1-D shear wave velocity structure is important for site effect studies and geotechnical engineering, but it is quite difficult and expensive to derive from the conventional geophysical techniques. Active (MASW) and passive (microtremors, HVSR) methods were conducted at 30 sites in the frontal part of the Himalaya which is characterized by soft sediments and strong seismological effects. Shear wave velocity (Vs) in the range of ~ 238 m/s to ~ 450 m/s has been obtained from 30 m thick layer of quaternary sediments overlying Lower Miocene bed rock (Upper Siwalik Conglomerate) in Jammu city, NW Himalaya. The shear wave velocity (Vs) along with seismic input motion of Chamoli earthquake (mb 6.8) has been used to obtain site response spectrum. The response spectrum suggests five to seven times increase in peak ground acceleration for single or two storey buildings and by eight to twelve times increase in amplification ratio with respect to input ground motion. The amplification spectrum shows peak amplification of ~ 2 Hz–~ 3 Hz in the central part and ~ 1.75 Hz–2 Hz in the northern, southwestern and southeastern parts of the city. The advantage of microtremor HVSR is that it yields direct estimate of the fundamental frequency which is found to vary from ~ 1 Hz to ~ 3 Hz for same sites. Further, the 1-D velocity models obtained from ModelHVSR Matlab routine have been compared with the soil models prepared by derived using MASW. The comparison shows correlation between soil models for sites having high shallow impedance contrast between the overlying sediments and very stiff material (bedrock) underneath as than sites having less impedance contrast.

Clockwise rotation and implications for northward drift of the western Transverse Ranges from paleomagnetism of the Piuma Member, Sespe Formation, near Malibu, California

New paleomagnetic results from mid‐Tertiary sedimentary beds in the Santa Monica Mountains reinforce the evidence for large‐scale rotation of the western Transverse Ranges, and anisotropy measurements indicate that compaction‐induced inclination flattening may resolve a long‐standing controversy regarding the original paleolatitude of the rotated block. Previously published paleomagnetic data indicate that post‐Oligocene rotation amounts to 70°–110° clockwise, affecting the Channel Islands, Santa Monica Mountains, and Santa Ynez Mountains. The Sespe Formation near Malibu consists of a lower member dominated by nonmarine sandstone and conglomerate and an upper section, the Piuma Member, which consists of gray‐red sandstone and mudstone interbedded with minor tuff and limestone beds. The Piuma Member has a paleomagnetic pole at 36.6°N, 326.7°E (A95min = 5.0°, A95max = 9.6°), obtained by thermal demagnetization of 34 oriented cores from Oligocene and early Miocene beds. After correcting for plunge of the geologic structure, the data are consistent with significant clockwise rotation (77° ± 7°) of the region relative to stable North America. Rotation of the western Transverse Ranges is generally viewed as a consequence of Pacific–North American plate interactions after 28 Ma, when east–west subduction gave way to northwest transform motion in southern California. Inclinations from the Piuma study indicate a paleolatitude anomaly of 11° ± 7° and are consistent with a mean northward drift that exceeds generally accepted San Andreas fault displacement by a factor of 3. However, sedimentary inclination error may accentuate the anomaly. Anisotropy of isothermal remanent magnetization indicates inclination flattening of approximately 8°, and correction for the effect reduces the paleolatitude anomaly to 5.3° ± 5.8°. Compaction may explain the inclination flattening in these sedimentary rocks, but the process does not adequately explain lower‐than‐expected inclinations found in previous studies of Miocene volcanic rocks of the western Transverse Ranges.

Scutellids from Miocene beds in Slovenia

In the article are considered sea urchins of family Scutellidae found in Slovenia. Two forms were determined: species Parascutella gibbercula (de Serres, 1829), occurring as a rule in Middle Miocene - Badenian lithothamnian limestones of Dolenjska and Štajerska, and species Parascutella paulensis (Agassiz, 1841), in Lower Miocene Govce clastic beds of Štajerska.

Scutellids from Miocene beds in Slovenia

In the article are considered sea urchins of family Scutellidae found in Slovenia. Two forms were determined: species Parascutella gibbercula (de Serres, 1829), occurring as a rule in Middle Miocene - Badenian lithothamnian limestones of Dolenjska and Štajerska, and species Parascutella paulensis (Agassiz, 1841), in Lower Miocene Govce clastic beds of Štajerska.

Two new species of seahorses (Syngnathidae, Hippocampus) from the Middle Miocene (Sarmatian) Coprolitic Horizon in Tunjice Hills, Slovenia: The oldest fossil record of seahorses

Two new and the only known extinct seahorse species Hippocampus sarmaticus and Hippocampus slovenicus are described from the Middle Miocene beds (Lower Sarmatian) in Slovenia, representing the oldest known fossil record of seahorses. Hippocampus sarmaticus was most similar to the extant seahorse species Hippocampus trimaculatus, while H. slovenicus can be most easily compared to the extant pygmy seahorses H. bargibanti, H. denise, and H. colemani. These Sarmatian seahorses lived among seagrasses and macroalgae in the temperate shallow costal waters of the western part of the Central Paratethys Sea.

Fabric variability within layered Fe-oxide deposits in Mid-Late Miocene sedimentary formations, NW Borneo: Impact on facies architectural interpretations

Iron (Fe) can accumulate in various forms in sedimentary environments that experience alternating moisture conditions, hydration and dehydration processes and redox processes. It has been pointed out that there is a major gap in the understanding of the composition of mixed solid-phase minerals, their size, morphology and arrangement in the matrix and possible interactions with pore solutions and the environment of deposition. Variations in the fabric within concretions in some Mid-Late Miocene beds in NW Borneo suggest that there were more changes in the energy levels and processes involved than what has been perceived from routine fabric analyses of the sedimentary rocks. The sedimentary rocks are essentially carbonaceous claystones containing varying amounts of highly restricted marginal-marine fauna. The fauna probably accumulated in brackish waters, and comprise in-situ buried turritellid snails, fish teeth and bone tissue, fragments of crabs, very few forams and possibly ostracod shells. Evidence exists to support the concept of reworked cobble or pebble-sized fossiliferous mudstone clasts picking up contemporaneous shell fragments in these restricted conditions. Iron oxide content is seen as (i) micrite-size primary components forming part of a muddy matrix and (ii) diagenetic coatings. Coatings occur in a non-rhythmical pattern after the formation of mudstones, and the reworking of the material and subsequent coatings by iron. Iron coated pebbles/cobbles may experience re-cementing into large sheets giving the appearance of red beds. These occur under some very special redox conditions. These iron-concretion rich horizons appear then to represent extreme (climatic, etc) facies developments that were restricted to coastal areas during Mid-Late Miocene. Present-day iron deposition processes might be a key to understanding past processes. This study forms the basis for an enhanced understanding on facies architectural interpretations.

A new stem-sperm whale (Cetacea, Odontoceti, Physeteroidea) from the Latest Miocene of Peru

A finely preserved skull with mandible and teeth associated, from the Latest Miocene beds (ca. 6 Ma) of the Pisco Formation, Sud-Sacaco, Peru, represents a new physeteroid genus and species, Acrophyseter deinodon. This moderate size sperm whale is characterized, among others, by: the short rostrum, the mandible distinctly curved upwards, large teeth very close together (12 on each upper tooth row and 13 on each lower tooth row), the lateral margin of the maxilla along the rostrum base much lower than the orbit roof, a wide supracranial basin dorsally overhanging the right orbit and limited to the cranium and a large temporal fossa dorsomedially elevated. A preliminary cladistic analysis provides a phylogenetic position of Acrophyseter nested within the stem-Physeteroidea, more basal than the clade Kogiidae + Physeteridae. The morphology of the oral apparatus and of the temporal fossa suggests that Acrophyseter was able to feed on large preys.

On richness and evenness within and between communities

Although there is extraordinary interest in the quantitative measurement of species diversity, published statements on the behavior of the components of species diversity are contradictory and lead to opposite conclusions. In this paper, we demonstrate that the confusion is due to two key oversights: (1) whether or not biological sampling is carried out within or between communities; and (2) determination of the statistical distribution underlying a biological community, which is crucial for the evaluation of all of the components of diversity measurement.The problem of sampling “within” a population or community is basically distinct from the equivalent integration of structure and diversity measurement “between” differing multispecies populations. “Within-community sampling” is defined as a set of biological samples from a statistical population that has a particular statistical distribution or a constant value for the associated parameter(s). As the number of individuals increases along with the number of species, for a log series distribution, the diversity measures of Shannon's H, log series or Fisher's α, and Simpson's Index 1/λ remain constant while the evenness measures of Buzas-Gibson's E and Pielou's J decrease. For a log-normal distribution, J will remain constant while E decreases and α, 1/λ, and H increase. No single measure of evenness remains constant over all statistical distributions, so if constancy as a type of independence is required, the appropriate distribution must first be determined. Each species ensemble is mathematically fixed by the applicable statistical distribution.In contrast, “between-community sampling” is defined as a set of biological samples from different statistical distributions and/or the same distribution with differing parametric values. If sampling is between communities and S increases while the number of individuals remains constant, then all the other measures considered here increase. The exception is the broken stick, for which E remains constant while H, J, α, and 1/λ increase.Herein we propose and justify the use of the log-series distribution (with regression on the information decomposition equation) as a null model for determination of community structure and demonstrate that the community structure of a Miocene bed at Calvert Cliffs, Maryland, is a log series by use of this new unified methodology.