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191 results for “early Oligocene”
Figure 7 in An assemblage of early Oligocene lizards (Squamata) from the locality of Boutersem (Belgium), with comments on the Eocene-Oligocene transition
Figure 7. Necrosaurus sp., fragment of maxilla, IRSNB R 248, previously BOU-AR-33-RS, medial view.
Morphometric data of the late middle Eocene to early Oligocene (~40 - 31 Ma) Coccolithophore Reticulofenestra (Order Isochrysidales)
<p><span>The first size reduction (FSR) in the <em>Reticulofenestra-Gephyrocapsa-Emiliania (RGE)</em> lineage (Order Isochrysidales) which occurred in the early Oligocene (~ 32 Ma), is of great significance for understanding the lilliput effect that has affected the coccolithophore communities from late Eocene to this day. We conducted a morphologic analysis on the coccoliths of <em>Reticulofenestra</em> species that lived during the late middle Eocene to early Oligocene (~40-31 Ma), using marine sediments from the South Atlantic Ocean. Our data show increasing size and decreasing abundance of the large species during the late Eocene, leading to their disappearance at the FSR, and a concurrent decrease in the size variability of the small-medium-sized coccoliths whose diameter of the central opening had become very reduced. Although the cosmopolitan late Paleogene through Neogene size decrease in coccolithophores has been linked to the concomitant long-term decline in global <em>p</em>CO2, we suggest here that the FSR was the result of environmental destabilization caused by the expansion of eutrophic environments following the late Eocene establishment of overturning circulation associated with ice build-up on Antarctica. This study also leads us to propose a hypothetical model that links coccolith morphology of species of the <em>RGE </em>lineage and trophic resources in the upper ocean: the small- to medium-sized, r-selected coccolithophores with smaller coccolith central opening live in nutrient-rich waters where they rely mostly on photosynthesis and little on mixotrophy; whereas the larger, K-selected species with larger coccolith central opening live in oligotrophic waters where they are more dependent on mixotrophy.</span></p>
Morphometric data of the late middle Eocene to early Oligocene (~40 - 31 Ma) Coccolithophore Reticulofenestra (Order Isochrysidales)
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Data from: Widespread loss of mammalian lineage and dietary diversity in the early Oligocene of Afro-Arabia
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Data from: Evidence for two sympatric sirenian species (Mammalia, Tethytheria) in the early Oligocene of Central Europe
The early Oligocene (Rupelian) sirenian Halitherium schinzii Kaup, 1838, which represents the type species of the genus Halitherium Kaup, 1838, is revised herein based on a morphological re-evaluation of skeletal material originally assigned to this taxon. This study provides new and comprehensive information on the cranial and postcranial anatomy and allows the distinction of two sympatric species. Following a recent approach on the invalidity and subsequent rejection of H. schinzii Kaup, 1838, Kaupitherium gruelli new genus new species is established on the basis of a nearly complete holotype. The second taxon resembles K. gruelli n. sp. in a number of skeletal features, such as reduced nasals and absence of the canines, but can be clearly distinguished mainly by the post-canine dental formula and the supraoccipital morphology. The diagnostic skullcap of a species formerly synonymized under "H. schinzii" is re-validated as the holotype of K. bronni (Krauss, 1858). On the basis of paleoecological implications, a hypothesis is established to explain the overlapping stratigraphic and biogeographic occurrences (i.e., sympatry of both taxa). A diagnosis and up-to-date synonymy complement the taxonomical information. The revision of "H. schinzii" provides new data on the past sirenian diversity and forms the basis for a taxonomic and systematic re-evaluation of species originally grouped in the genus "Halitherium."
FIGURE 4 in A new species of Trachytherus (Notoungulata: Mesotheriidae) from the late Oligocene (Deseadan) of Southern Peru and the middle latitude diversification of early diverging mesotheriids
FIGURE 4. Manual elements of Trachytherus spp. A, Trachytherus ramirezi, right distal ulna and radius (with unfused radial epiphysis), carpals (missing trapezium and pisiform) and proximal metacarpals II–V (MUSM 963); B, right carpals (missing trapezoid and pisiform) and damaged Mc I–V (MUSM 965) of small indeterminate species of Moquegua; C, nearly complete right manus of cf. T. spegazzinianus (MUSM 668); left manus of T. alloxus (UF 91933, reversed to show as right). Abbreviations: cun, cuneiform; ln, lunate; Mc, metacarpal; mg, magnum; pis, pisiform; sc, scaphoid; td, trapezoid; tm, trapezium. Scale bar applies to all.
FIGURE 2 in A new species of Trachytherus (Notoungulata: Mesotheriidae) from the late Oligocene (Deseadan) of Southern Peru and the middle latitude diversification of early diverging mesotheriids
FIGURE 2. Holotype Trachytherus ramirezi sp. nov., MUSM 350. A, right lateral view of cranium and mandible; A', detail of external auditory region of A; B, skull in left lateral view to illustrate the damaged side, revealing the mesodont-to-hypsodont premolars, somewhat hypsodont (rooted) M1, and hypselodont M2–3; C, ventral view of skull and palate; and D, occlusal view of jaw and lower dentitions. Abbreviations: bc, braincase; crm, crista meatus; eam, external auditory meatus; ets, epitypmanic sinus; gf, glenoid fossa; msty, metastyle; pgp, post glenoid process; rtp, retrotympanic process; and smf, suprameatal fossa. Scale bar at D applies to all, except the slightly enlarged A'.
FIGURE 1 in A new species of Trachytherus (Notoungulata: Mesotheriidae) from the late Oligocene (Deseadan) of Southern Peru and the middle latitude diversification of early diverging mesotheriids
FIGURE 1. Map of South America showing the approximate locations of sites that have yielded remains of Oligocene mesotheriids: stars are to indicate locations of undescribed/unclassified Tinguirirican mesotheriid materials; octagons indicate the widely dispersed, Deseadan Trachytherus spegazzinianus; and diamonds indicate localities containing all other recognized species of Trachytherus (Deseadan). The dashed oval circumscribes the area we refer to as the "Bolivian Oroclinal Region," an area that contains all four recognized species of Trachytherus (see text for details). Background map modified from NASA image.
FIGURE 7 in A new species of Trachytherus (Notoungulata: Mesotheriidae) from the late Oligocene (Deseadan) of Southern Peru and the middle latitude diversification of early diverging mesotheriids
FIGURE 7. Phylogeny and historical biogeography of the Mesotheriidae. Cladograms of A and B were based upon the phylogenetic analysis in this study for the early diverging, non-mesotheriine mesotheriids (without the Deltran optimization given fig. 6) combined with the analysis of Croft et al. (2004) for the Mesotheriinae (see also Flynn et al. 2003). That of A includes the "published mesotheriid" (PM) dataset only, whereas B, the "undescribed plus published mesotheriids (U+PM), includes undescribed Tinguirirican material. Question marks indicate the uncertainties of affinities of the Tinguirirican taxa and that of an indeterminate mesotheriine Colhuehuapian (see text). Lines from taxon to map of South America are to indicate the general region(s) from which the taxa are known. The reconstructions of ancestral area presented here are based on the single character coding strategy (see Material and Methods). The bold lines of the cladogram indicate the evolution of the BOR distribution on the tree, whereas thin stems indicate distribution in SSA (see text for comments).
FIGURE 4. Palaeogeographic Setting for the early Austrobalanidae. 4a in A review of the subfamily Eliminiinae (Cirripedia: Thoracica: Austrobalanidae), including a new genus, Protelminius nov., from the Oligocene of New Zealand
FIGURE 4. Palaeogeographic Setting for the early Austrobalanidae. 4a: Sketch depicting the oceanic systems that are likely to have operated in the south Pacific region during the late Palaeocene-early Eocene. At this time, the Antarctic continent was kept essentially ice-free by a large south Pacific warm-water gyre; counter-currents operating off Antarctic provided an opportunity for westward dispersal of Austrobalanus (to the McMurdo region and the proto-New Zealand land mass "NZ"). The dashed line represents a likely mobile transitional zone between marine regression and transgression. 4b: Southern ocean conditions during the Oligocene to early Miocene, after the initiation of the Antarctic Circumpolar Current. With the loss of the southern pacific warm-water gyre, glaciation of the Antarctic continent began (e.g. Kennett, 1977), with the resultant regional extinction of austrobalanid barnacles. The heavier dotted blue line represents the likely position of the cold and temperate water systems convergence. (Reconstruction adapted from Markwick et al., 1999; Barron and Peterson, 1991; Nelson and Cooke, 2001).
Fig. 3 in Multigene fossil-calibrated analysis of the African lampeyes (Cyprinodontoidei: Procatopodidae) reveals an early Oligocene origin and Neogene diversification driven by palaeogeographic and palaeoclimatic events
Fig. 3 Phylogenetic relationships between African lampeyes genera as depicted in Huber (1999) and Ghedotti (2000)
Fig. 1 Phylogenetic relationships among 36 in Multigene fossil-calibrated analysis of the African lampeyes (Cyprinodontoidei: Procatopodidae) reveals an early Oligocene origin and Neogene diversification driven by palaeogeographic and palaeoclimatic events
Fig. 1 Phylogenetic relationships among 36 species of Procatopodidae, including all genera but Aapticheilichthys, inferred by using partial sequences of the nuclear-encoded genes GLYT1, ENC1, RAG1, MYH6, and SREB2, a total of 5009 bp. Numbers left to the bar indicate posterior probability values and in the right are bootstrap support values taken from the maximum likelihood analysis. Asterisk means maximum values. The green dot next to species name refers to species occurring in rainforests, red dot refers to species occurring in savannahs, green/red dot refer to
Figure 2 in New remains of a gavialoid crocodilian from the late Oligocene-early Miocene of the Pirabas Formation, Brazil
Figure 2. Gavialoid indet., partial symphyseal portion of mandible, MPEG 1130-V: A, ventral view and A1, schematic ventral view; B, lingual view and B1 schematic ventral view; C, right lateral view.
Figure 1 in New remains of a gavialoid crocodilian from the late Oligocene-early Miocene of the Pirabas Formation, Brazil
Figure 1. Summary map of the study region in north-east South America, showing the localities discussed in the text.
Data from: Evidence for two sympatric sirenian species (Mammalia, Tethytheria) in the early Oligocene of Central Europe
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Data from: A new specimen of Agorophius pygmaeus (Agorophiidae, Odontoceti, Cetacea) from the Early Oligocene Ashley Formation of South Carolina, USA
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FIG. 4. — A in Carnivora from the early Oligocene of the ' Phosphorites du Quercy' in southwestern France
FIG. 4. — A, Mustelictis cf. major, right hemi-mandible with p2-p4-m1, UM VD17, in buccal (A1), lingual (A2), and occlusal (A3) views; B, Mustelictis aff. olivieri, left hemi-mandible with p4-m2, UP LPL12, in buccal (B1), lingual (B2), and occlusal (B3) views; C-E, Mustelictis aff. olivieri; C, left m1, UP LPL11, in buccal (C1), and lingual (C2) views; D, right m1, UM VBOA3-4, in buccal (D1) view, occlusal (D2) view, and lingual (D3) views; E, right hemi-mandible with d3-d4, UP MGB6, in lingual (E1), and buccal (E2) views; F, Mustelictis olivieri, left mandible with p3-m1, UP MGB8, in buccal (F1), and lingual (F2) views; G, Mustelictis aff. olivieri, right hemi-mandible with p2-p4, UM VD12, in buccal (G1) view, and lingual (G2) views; H, Peignictis pseudamphictis n. gen., n. sp., right hemimandible with m1, UM VD1, in buccal (H1), lingual (H2), and occlusal (H3) views. Scale bars: 5 mm.
FIG. 1. — A in Carnivora from the early Oligocene of the ' Phosphorites du Quercy' in southwestern France
FIG. 1. — A, Amphicynodon sp. 1: left hemi-mandible UP VAL2, in buccal (A1), lingual (A2), and occlusal (A3) views; B, Amphicynodon typicus: left mandible UP VAL1, in buccal (B1), lingual (B2), and occlusal (B3) views; C, Amphicynodon sp. 3: right M1, UM VD49, in occlusal view; D, Amphicynodon sp. 2: right M1, UM VBO492, in occlusal view. Scale bars: A, B, 10 mm; C, D, 5 mm.
FIG. 3. — A in Carnivora from the early Oligocene of the ' Phosphorites du Quercy' in southwestern France
FIG. 3. — A, Pachycynodon sp. 3, left M1-M2, UM VD47, in occlusal view; B, Pachycynodon cf. filholi, UM VD5, left hemi-mandible, in buccal (B1), lingual (B2), and occlusal (B3) views; C-E, Pachycynodon cf. dubius; C, left hemi-mandible UM VD14, in buccal (C1), lingual (C2), and occlusal (C3) views; D, right hemimandible UM VD4, in lingual (D1) and buccal (D2) views; E, right hemimandible VD6, in buccal (E1), and occlusal (E2) views; F, Cephalogale sp., left mandible UP MGB26, in lingual (F1), and buccal (F2) views; G, Pachycynodon sp. 5, left P4 UP VD51, in occlusal (G1), and mesial (G2) views; H, Pachycynodon cf. filholi, right m2, UP LPL14, in occlusal view. Scale bars: 5 mm.
FIG. 2. — A in Carnivora from the early Oligocene of the ' Phosphorites du Quercy' in southwestern France
FIG. 2. — A, Pachycynodon boriei or curvirostris (Filhol, 1876): A1-A3, UP LPL13, right m1, in buccal (A1), lingual (A2), and occlusal (A3) views; A4, A5, d3-d4, in buccal (A4), and lingual (A5) views; B, C, Pachycynodon sp. 1; B, UP MGB9, left d4, in buccal (B1), lingual (B2), and occlusal (B3) views (stereo); C, UM VD16, right d4, in buccal (C1), lingual (C2) view, and occlusal (C3) views; D, Pachycynodon sp. 2, UM VD18, right d4; D1, lingual view, occlusal (D2), and buccal (D3) views; E, Pachycynodon cf. filholi, UM VD7, left hemi-mandible, in buccal (E1), lingual (E2), and occlusal (E3) views; F, Pachycynodon sp. 3, UM VD48 M1, in occlusal view; G, Pachycynodon sp. 4, UM VD50 M1, in occlusal view. Scale bars: 5 mm.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.