The Inachoididae spider crabs (Crustacea, Brachyura) from the Neogene of the tropical Americas

Abstract The spider crabs Willinachoides santanai n. gen. n. sp. from the early-middle Miocene of north Brazil and Paradasygyius rodriguezi n. sp. from the late Miocene of Venezuela are described and illustrated. Additionally, Eoinachoides senni Van Straelen, 1933, from the late Oligocene–early Miocene of Venezuela, is redescribed based on photographs of the holotype, and the diagnosis of Eoinachoides latispinosus Carriol, Muizon, and Secretan, 1987, from the late Miocene of Peru, is emended also on the basis of photographs of the holotype. The past distribution points to a Tethyan background for the current amphi-American Inachoididae, with the oldest fossil species known from the early Eocene Tethyan regions (Pakistan and Italy), and from the late Eocene–late Pliocene of the Americas. The high number of monotypic genera in Inachoididae could be the result of rapid dispersion followed by diversification during the Neogene of the tropical America, facilitated by global and regional events (e.g., eustatic sea level changes, the Mi-1 Oligocene-Miocene boundary global cooling, the global warming period of the Middle Miocene Climate maximum, closure of the Panama Isthmus, and marine incursions into the Amazon Basin). The shoaling and final closure of the Central American Seaway are thought to have critically affected the evolution of the inachoidids and shaped their current distribution patterns. UUID: http://zoobank.org/6275fdc4-4bfa-4873-9320-3143d4915172.

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Tertiary marine molluscan assemblages of eastern Patagonia (Argentina): A biostratigraphic analysis

Journal of Paleontology ◽

10.1017/s0022336000043912 ◽

2004 ◽

Vol 78 (6) ◽

pp. 1097-1122 ◽

Cited By ~ 17

Author(s):

Claudia Julia del Río

Keyword(s):

Late Miocene ◽

Middle Miocene ◽

Late Eocene ◽

Early Miocene ◽

Late Oligocene ◽

Late Paleocene ◽

Compositional Changes ◽

Molluscan Species

Pectinids are the most abundant and widely distributed taxa in the Tertiary marine beds of Patagonia. Along with other very common molluscan species, they characterize five assemblages, from oldest to youngest: 1) the Oligocene Panopea sierrana-Parinomya patagonensis Assemblage; 2) the Late Oligocene–Early Miocene Jorgechlamys centralis–Reticulochlamys borjasensis Assemblage; 3) the Early Miocene Reticulochlamys zinsmeisteri–Struthiolarella patagoniensis–Pleuromeris cruzensis Assemblage; 4) the Early Miocene Pseudoportlandia glabra–Antimelatoma quemadensis Assemblage; and 5) the latest Early Miocene–earliest Middle Miocene Nodipecten sp.–Venericor abasolensis–Glycymerita camaronesia Assemblage. A brief analysis of the origin and composition of these Tertiary Patagonian molluscan faunas is provided. Striking compositional changes occurred through time, recorded mainly in the Late Paleocene, Late Eocene, Late Oligocene–Early Miocene, and Late Miocene.

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Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system

Brazilian Journal of Geology ◽

10.1590/2317-4889201620160066 ◽

2016 ◽

Vol 46 (2) ◽

pp. 301-328 ◽

Cited By ~ 14

Author(s):

Mario Vicente Caputo ◽

Emilio Alberto Amaral Soares

Keyword(s):

South America ◽

Atlantic Ocean ◽

Sea Level ◽

Late Miocene ◽

Middle Miocene ◽

Drainage System ◽

Sedimentary Basins ◽

Amazon River ◽

Drainage Network ◽

Sea Level Changes

ABSTRACT: The development of the transcontinental Amazon River System involved geological events in the Andes Chain; Vaupés, Purus and Gurupá arches; sedimentary basins of the region and sea level changes. The origin and age of this river have been discussed for decades, and many ideas have been proposed, including those pertaining to it having originated in the Holocene, Pleistocene, Pliocene, Late Miocene, or even earlier times. Under this context, the geology of the sedimentary basins of northern Brazil has been analyzed from the Mesozoic time on, and some clarifications are placed on its stratigraphy. Vaupés Arch, in Colombia, was uplifted together with the Andean Mountains in the Middle Miocene time. In the Cenozoic Era, the Purus Arch has not blocked this drainage system westward to marine basins of Western South America or eastward to the Atlantic Ocean. Also the Gurupá Arch remained high up to the end of Middle Miocene, directing this drainage system westward. With the late subsidence and breaching of the Gurupá Arch and a major fall in sea level, at the beginning of the Late Miocene, the Amazon River quickly opened its pathway to the west, from the Marajó Basin, through deep headward erosion, capturing a vast drainage network from cratonic and Andean areas, which had previously been diverted towards the Caribbean Sea. During this time, the large siliciclastic influx to the Amazon Mouth (Foz do Amazonas) Basin and its fan increased, due to erosion of large tracts of South America, linking the Amazon drainage network to that of the Marajó Basin. This extensive exposure originated the Late Miocene (Tortonian) unconformity, which marks the onset of the transcontinental Amazon River flowing into the Atlantic Ocean.

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A Middle to Late Miocene Trans-Andean Portal: Geologic Record in the Tatacoa Desert

Frontiers in Earth Science ◽

10.3389/feart.2020.587022 ◽

2021 ◽

Vol 8 ◽

Author(s):

C. Montes ◽

C. A. Silva ◽

G. A. Bayona ◽

R. Villamil ◽

E. Stiles ◽

...

Keyword(s):

Late Miocene ◽

Amazon Basin ◽

Middle Miocene ◽

Middle Eocene ◽

Structural Data ◽

Coverage Area ◽

Geologic Record ◽

Mapping Models ◽

Central Cordillera ◽

Lines Of Evidence

Integration of several geologic lines of evidence reveals the prevalence of a lowland trans-Andean portal communicating western Amazonia and the westernmost Andes from at least middle Miocene until Pliocene times. Volcanism and crustal shortening built up relief in the southernmost Central and Eastern Cordilleras of Colombia, closing this lowland gap. Independent lines of evidence consist first, of field mapping in the Tatacoa Desert with a coverage area of ∼381 km2, 1,165 km of geological contact traces, 164 structural data points, and 3D aerial digital mapping models. This map documents the beginning of southward propagation of the southernmost tip of the Eastern Cordillera’s west-verging, fold-and-thrust belt between ∼12.2 and 13.7 Ma. Second, a compilation of new and published detrital zircon geochronology in middle Miocene strata of the Tatacoa Desert shows three distinctive age populations: middle Miocene, middle Eocene, and Jurassic; the first two sourced west of the Central Cordillera, the latter in the Magdalena Valley. Similar populations with the three distinctive peaks have now been recovered in western Amazonian middle Miocene strata. These observations, along with published molecular and fossil fish data, suggest that by Serravallian times (∼13 Ma), the Northern Andes were separated from the Central Andes at ∼3°N by a fluvial system that flowed into the Amazon Basin through the Tatacoa Desert. This paleogeographic configuration would be similar to a Western Andean, or Marañon Portal. Late Miocene flattening of the subducting Nazca slab caused the eastward migration of the Miocene volcanic arc, so that starting at ∼4 Ma, large composite volcanoes were built up along the axis of today's Central Cordillera, closing this lowland Andean portal and altering the drainage patterns to resemble a modern configuration.

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Three new fossil records of Equisetum (Equisetaceae) from the Neogene of south-western China and northern Vietnam

PhytoKeys ◽

10.3897/phytokeys.138.38674 ◽

2020 ◽

Vol 138 ◽

pp. 3-15 ◽

Cited By ~ 1

Author(s):

Aye Thida Aung ◽

Jian Huang ◽

Truong Van Do ◽

Ai Song ◽

Jia Liu ◽

...

Keyword(s):

Species Richness ◽

Late Miocene ◽

Yunnan Province ◽

Middle Miocene ◽

Western China ◽

Fossil Species ◽

Late Pliocene ◽

Northern Vietnam ◽

Fossil Records ◽

Fibrous Roots

Three fossil species of Equisetum (Equisetaceae) were reported from the Neogene of south-western China and northern Vietnam, based on well-preserved rhizomes with tubers. Equisetum cf. pratense Ehrhart from the middle Miocene of Zhenyuan County, Yunnan Province, China is characterised by a bunch of three ovate tubers with longitudinal ridges on the surface. Equisetum yenbaiense A.T. Aung, T. Su, T.V. Do & Z.K. Zhou, sp. nov. from the late Miocene of Yenbai Province, Vietnam is characterised by four bunches of elongate tubers arranged in a whorl on a node. Equisetum yongpingense A.T. Aung, T. Su & Z.K. Zhou, sp. nov. from the late Pliocene of Yunnan is characterised by fibrous roots on most nodes and two to four bunches of large cylindrical tubers arranged in a whorl on a node. Floristic assemblages suggest that these species might have grown near a riverside or lakeshore. These new fossil records improve our understanding of species richness of Equisetum and their distribution range during the Neogene in Asia.

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A pre-cursor extensive Miocene reef system to the Rowley Shoals reefs, Western Australia: evidence for structural control of reef growth or natural hydrocarbon seepage?

The APPEA Journal ◽

10.1071/aj08021 ◽

2009 ◽

Vol 49 (1) ◽

pp. 337 ◽

Cited By ~ 9

Author(s):

Georgina Ryan ◽

George Bernardel ◽

John Kennard ◽

Andrew T Jones ◽

Graham Logan ◽

...

Keyword(s):

Sea Level ◽

Fault Zone ◽

Western Australia ◽

Growth Phase ◽

Late Miocene ◽

Structural Control ◽

Middle Miocene ◽

Reef Growth ◽

Sea Level Changes ◽

North West

Numerous Miocene reefs and related carbonate build-ups have been identified in the Rowley Shoals region of the central North West Shelf, offshore Western Australia. The reefs form part of an extensive Miocene reef tract over 1,600 km long, which extended northward into the Browse and Bonaparte basins and southward to North West Cape in the Carnarvon Basin—comparable in length to the modern Great Barrier Reef. Growth of the vast majority of these Miocene reefs failed to keep pace with relative sea-level changes in the latest Miocene, whereas reef growth continued on the central North West Shelf to form the three present-day atolls of the Rowley Shoals: Mermaid, Clerke and Imperieuse reefs. In the Rowley Shoals region, scattered small build-ups and local reef complexes were first established in the Early Miocene, but these build-ups were subsequently terminated at a major Mid Miocene sequence boundary. Widespread buildups and atoll reefs were re-established in the Middle Miocene, and the internal stacking geometries of the reefs appear to relate to distinct growth phases that are correlated with eustatic sea-level fluctuations. These geometries include: a basal aggradational buildup of early Middle Miocene age; a strongly progradational growth phase in the late Middle to early Late Miocene that constructed large reef atolls with infilling lagoon deposits; and a back-stepped aggradational growth phase that formed smaller reef caps in the early–latest Late Miocene. Growth of the majority of the reefs ceased at a major sea-level fall in the Late Miocene (Messinian), and only the reefs of the present-day Rowley Shoals (Mermaid, Clerke and Imperieuse reefs, as well as a drowned shoal to the southwest of Imperieuse Reef) continued to grow after this event. Growth of the Rowley Shoals reefs continued to keep pace with Pliocene-Recent sea-level changes, whereas the surrounding shelf subsided to depths of 230–440 m. We conclude that initial reef growth in the Rowley Shoals region was controlled by transpressional reactivation and structuring of the Mermaid Fault Zone during the early stage of collision between the Australian and Eurasian plates. During this structural reactivation, seabed fault scarps and topographic highs likely provided ideal sites for the initiation of reef growth. The subsequent growth and selective demise of the reefs was controlled by the interplay of eustatic sea-level variations and differential subsidence resulting from continued structural reactivation of the Mermaid Fault Zone. In contrast to models proposed in other regions, there is no direct evidence that active or palaeo hydrocarbon seepage triggered or controlled growth of the Rowley Shoals reefs or their buried Miocene predecessors.

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Late middle Miocene Konan flora from northern Hokkaido, Japan

10.35535/acpa-2020-0012 ◽

2020 ◽

pp. 259-295

Author(s):

Atsufumi Narita ◽

Atsushi Yabe ◽

Kazuhiko Uemura ◽

Midori Matsumoto

Keyword(s):

Late Miocene ◽

Middle Miocene ◽

Plant Macrofossils ◽

Common Species ◽

Climatic Conditions ◽

Temperate Climate ◽

Relict Species ◽

Fossil Species ◽

Late Middle Miocene ◽

Cool Temperate

Plant macrofossils from the upper middle Miocene Konan Tuffaceous Sandstone and Mudstone Member of the Bifuka Formation, known as the Konan flora, northwest of Shibetsu City, Hokkaido, Japan, were taxonomically revised. A total of 31 taxa were recognized, which were assigned to 14 families and 19 genera, including a new fossil species, Salix palaeofutura sp. nov. The Konan flora includes three taxa of evergreen conifers, one perennial monocot herb and 27 deciduous dicots. The most abundant and common species were Fagus palaeojaponica, Acer subcarpinifolium, Acer protojaponicum, Picea sp. A and Cercidiphyllum crenatum, in addition to a number of species of the Betulaceae and Salicaceae. From the absence of evergreen angiosperms as well as the common occurrence of Fagus palaeojaponica, Picea, Acer and Betulaceae species, this flora was comparable to that seen in the modern Mixed Northern Hardwood Forest of East Asia, which is distributed in northernmost Honshu and extends toward lowland Hokkaido. On the basis of floral features, mode of occurrence, and the lithology of plant-bearing beds, the Konan flora was deemed to represent mountain to riverside vegetation with humid and cool temperate climatic conditions. In contrast to the early to late Miocene floras in Japan, the Konan flora belongs to the late Miocene–Pliocene Mitoku-type flora, with a few relict species from the early Miocene. The Konan flora represents one of the earliest occurrences of this type of flora, suggesting that floral modernization was initiated much earlier in areas with humid and cool temperate climate than previously thought.

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