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1.
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.  相似文献   

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Several isolated cheek teeth and mandibular specimens of Rhinocerotidae (Mammalia, Perissodactyla) from the upper Miocene Namurungule Formation in Samburu Hills, Kenya, are redescribed. Previously, these specimens had been identified as Chilotheridium pattersoni, Chilotheridium sp., Paradiceros mukirii, and Paradiceros sp. They are reidentified here as documenting the genus Brachypotherium based on their bucco-lingually broad molariform upper premolars with short crochet and flattened buccal walls on both upper and lower molars, the latter having a shallow external groove. Comparisons with other Brachypotherium species suggest that the present specimens belong to Brachypotherium sp. cf. B. minor. The presence of Brachypotherium in the Samburu Hills, at ca. 9.5 Ma, is concordant with the paleoenvironment (presence of lacustrine and river environments) known for this locality during the early late Miocene.  相似文献   

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A skeleton fragment of a spadefoot toad (family Pelobatidae Bonaparte, 1850) from the Middle Miocene (Early Sarmatian) of the Karpov Yar locality (northern Moldova) is described. Since the material is incomplete, it is only determined as Pelobatidae gen. indet. This is the first spadefoot toad from the Miocene of Moldova.  相似文献   

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Eohomopterus simojovelensis n. sp., the first fossil record of the subfamily Paussinae (Coleoptera: Carabidae) from the Miocene amber of the Simojovel area, Chiapas, Mexico, is described. The morphology of the new species is compared withEohomopterus poinari Nagel, 1997 from Dominican amber as well as with extant representatives ofEohomopterus, and the biogeographical implications are discussed.   相似文献   

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A high-resolution palynological study of the cyclically bedded Faneromeni section (upper Tortonian-lower Messinian) on Crete (Greece) is presented. This study aims to recognize orbitally-driven variations in the palynological record and to validate the age model based on the astronomical calibration of the sedimentary cycles. Four palynology-based environmental proxies were utilised using interpretations of fossil dinoflagellate associations based on modern ecological characteristics. Cross-spectral analysis between the proxy records and astronomical target curve, the 65°N summer insolation, yielded in most cases significant spectral power and coherence in the precession and/or obliquity frequency bands. Precession-controlled variations in the proxy records are related to lithology and indicate that maxima in continental input and minima in sea surface salinity coincide with sapropel formation. The influence of obliquity is most clearly reflected in the index of continental versus marine palynomorphs (S-D). The absence of a distinct time lag relative to obliquity indicates that the 41-kyr component in continental input is controlled by oscillations in regional Mediterranean climate rather than by glacial cyclicity. Phase relations in the different astronomical frequency bands of the spectrum, as compared with the Mediterranean Pliocene, essentially confirm the validity of the Miocene astronomical time scale. Finally, a major non-cyclic change in the palynological assemblage at 6.68 Ma indicates enhanced salinity and decreased river discharge. This shift coincides with a significant drop in sedimentation rate informally termed the “Early Messinian Sediment starvation Event”.  相似文献   

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The Early/Middle Miocene boundary locality Sandelzhausen (MN5, southern Germany) yielded three beaver teeth: one lower incisor fragment and two strongly worn upper premolars, a right and a left one. The latter are so similar in wear, height, size, and enamel pattern that they probably represent one individual. Although the teeth have been referred to Chalicomys jaegeri Kaup, 1832 (e.g., Hugueney 1999, Fahlbusch 2003), it seems more likely that they belong to Steneofiber depereti Mayet, 1908. However, the assignment of the present material to either one of these species is difficult, because in the advanced wear stage some diagnostic characteristics cannot be assessed. As to ecological implications for the locality Sandelzhausen the taxonomic identity of these two beaver species may not be important. Both are known from riverine, lacustrine or swamp sediments, and it can be assumed that they usually lived in close vicinity to water. Thus, the presence of beaver remains supports the presence of water at Sandelzhausen. However, the teeth might have an allochthonous origin from creeks of the rising Alps.   相似文献   

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A new fossil species of Vallisneria (V. janecekii Bogner & Kva?ek, sp. n., Hydrocharitaceae) is reported from Early Miocene freshwater lake deposits of the North Bohemian brown coal basin (Czech Republic). It is based on a single fragmentary sterile plant bearing two clusters of ribbon-shaped widely serrulate leaves on a short rhizome. It is a potential producer of seeds described from equivalent and slightly older deposits in Saxony (Germany) as Vallisneria ovalis Mai.  相似文献   

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This paper documents the first record of silicified fossil wood from a previously undescribed wood-rich horizon in the Sitakund Anticline, Eastern Bangladesh. The outcrop is composed of cross-stratified, fine-medium grained sandstones with bidirectional cross stratification indicative of a tidal environment, deposited ca. 5-5.2 million years before present (Miocene/Pliocene). The wood is characterised by large solitary vessels with alternate intervascular pits, banded parenchyma, uniseriate rays, and multiseriate rays with one radial canal per ray. This character combination closely resembles the wood of extant Gluta L. of the Anacardiaceae. This specimen has been assigned to the organ genus Glutoxylon Chowdhury erected for fossil woods with anatomical similarity to Gluta (including Melanorrhoea Wall.). The excellent preservation of this mature wood specimen illustrates the potential for using fossil wood from the Sitakund locality for palaeoecological studies in terms of biodiversity and adaptational response to climate change. Moreover such investigations of fossil woods from Bangladesh will compliment studies undertaken on fossil plants in other parts of Central and Southeastern Asia which will further the understanding of plant migration routes between India and Southeast Asia during the Tertiary.  相似文献   

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An abundant fossil record of the snake clade Scolecophidia exists in Europe; however, the minute snake is noticeably absent in reports about the North American Paleogene and Neogene. Presented here are four localities from Florida, USA, that contain scolecophidian remains older than the Pleistocene: Thomas Farm (late Early Miocene, Hemingfordian Land Mammal Age, LMA), Live Oak (Oligocene-Miocene transition, latest Arikareean LMA), White Springs 3B (late Arikareean LMA), and Brooksville 2 (Late Oligocene, middle Arikareean LMA). These remains extend their known existence by about 26 m.y. and are now the oldest reported scolecophidian remains in North America. Molecular evidence on extant scolecophidians concludes that these tiny snakes have a Gondwanan origin. Interestingly, the oldest record of a scolecophidian is from Europe (Belgium) and dates back to the middle Paleocene (MP 1–5). The earliest African record of the snake clade comes from the Paleocene-Eocene boundary in Morocco. The clade is apparently absent from Europe and Middle East deposits dating from the latest Eocene through to the latest Oligocene (MP 19–30) and to the Early Miocene (MN 4). A portion of this time is known as the booid ‘Dark Period’ which represents an apparent response to global aridization and cooling. Scolecophidians appear to re-emerge into the southern Eurasian record in the Early Miocene (MN 4) and become widely dispersed throughout Europe and Middle East. The fossil record of these minute snakes is largely absent in southern Asia and South America. It is possible that the current lack of a decent fossil scolecophidian record outside of Europe and Middle East is due mainly to a bias in the methodology to recover fossils; wet sieving sediments through < 1.0 mm mesh is needed to recover the minuscule vertebrae.  相似文献   

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A complete tarsometatarsus of a passerine bird from the early Miocene (MN 3) of Petersbuch (Bavaria, Germany) is identified as an extinct representative of the climbing Certhioidea, i.e., a clade comprising treecreepers (Certhiidae), nuthatches and wallcreepers (Sittidae). The fossil specimen represents the so far earliest evidence of a representative of the Certhioidea and is described as †Certhiops rummeli gen. et sp. nov. Similarities to other climbing passerines are discussed.  相似文献   

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From the Bavarian Early/Middle Miocene (MN5) site Sandelzhausen, nine species of carnivoran mammals are identified including the hemicyonine ursid Hemicyon stehlini, the amphicyonids Amphicyon cf. major and Pseudarctos bavaricus, the mustelids Ischyrictis zibethoides and Martes cf. munki, the mephitid Proputorius pusillus, the viverrid Leptoplesictis cf. aurelianensis, the felid Pseudaelurus romieviensis, and finally the recently described barbourofelid Prosansanosmilus eggeri. With these taxa present, Sandelzhausen shows a carnivoran community typical, though deprived, for the Lower to Middle Miocene of Europe, but different from roughly contemporary Mediterranean faunas such as those from Çandir or Pa?alar in Turkey.  相似文献   

16.
M. Prein  A. Kunzmann 《Zoomorphology》1987,107(3):161-168
Summary The morphology and structural features of the gills of the two Western Baltic pipefish Nerophis ophidion and Syngnathus rostellatus were investigated using scanning electron microscopy. The general anatomy of the gills complies with the general pattern in fish. Several adaptations though, show the highly specialized nature of pipefish gills. The filaments are extremely short, few in number and carry only a few lamellae due to the limited space in the branchial cavity. The lamellae have a widely projecting form yet still have a small area in comparison to other fish. Gill irrigation is performed by a specialized pumping mechanism which forces respiratory water through the small but densely packed gill sieve. Although both species live in the same habitat and belong to the same family, differences in gill morphology were found and are related to different lifestyles. S. rostellatus is the more active species and therefore has more filaments per gill arch, more lamellae per filament, wider projecting lamellae and a more extreme utilisation of available space in the gill cavity through a very densely packed gill sieve. N. ophidion has a stationary mode of life and therefore has a less extreme gill anatomy.  相似文献   

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The foveal and non-foveal retinal regions of the pipefish, Corythoichthyes paxtoni (Syngnathidae, Teleostei) are examined at the level of the light and electron microscopes. The pipefish possesses a deep, pit (convexiclivate) fovea which, although lacking the displacement of the inner retinal layers as described in other vertebrate foveae, is characterised by the exclusion of rods, a marked increase in the density of photoreceptors and a regular square mosaic of four double cones surrounding a central single cone. In the perifoveal and peripheral retinal regions, the photoreceptor mosaic is disrupted by the insertion of large numbers of rods, which reduce spatial resolving power but may uniformly increase sensitivity for off-axis rays. In addition to a temporal fovea subtending the frontal binocular field, there is also a central area centralis subtending the monocular visual field. Based on morphological comparisons with other foveate teleosts, four foveal types are characterised and foveal function discussed with respect to the theoretical advantage of a regular square mosaic.  相似文献   

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A new genus, Naslavcea, is erected for the Middle Miocene species Spicara fundata Bannikov, 1990 (Centracanthidae) from the Lower Sarmatian of northern Moldova. This genus is characterized by the relatively small number of rays in the dorsal and anal fins. At the same time, Pelates islamdagicus Prokofiev, 2001 from the Lower Miocene of the Apsheron Peninsula (Azerbaijan) is transferred from the family Terapontidae to Centracanthidae and referred to the genus Spicara.  相似文献   

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