Evidence of seasonal growth in Tertiary vertebrate fossils

1968 ◽  
Vol 42 (S2) ◽  
pp. 119-119
Author(s):  
M. R. Voorhies
Keyword(s):  
Middle Eocene ◽  
Early Summer ◽  
Carbonate Precipitation ◽  
Seasonal Growth ◽  
Age At Death ◽  
Green River ◽  
Quantitative Studies ◽  
Summer Maximum ◽  
Time Of Year ◽  
River Fish

In modern vertebrates, particularly ectotherms in temperate climates, alternating periods of rapid and curtailed growth are often recorded by annual markings in bones and/or scales. By indicating the age at death of individual animals and the time of year when death occurred, such markings permit quantitative studies of growth rates and population dynamics of fossil vertebrates to be made, and aid in interpreting the origin of fossil deposits. Scales of fish collected from the varved, lacustrine Green River Formation (middle Eocene), southwestern Wyoming, show interruptions interpreted as annuli. The position of the most recent annulus relative to the edge of the scales indicates the season of death of individual fish. Perfectly preserved specimens died in early summer, whereas those that died at a later season are disarticulated and scattered. A likely explanation is that early summer mortalities coincided with the yearly summer maximum of carbonate precipitation in the lake, so that carcasses reaching the bottom at this time were protected from disruptive currents. Among a collection of early Pliocene vertebrates from a quarry in Nebraska are many specimens from which individual age and season of death can be determined. Annuli on gar scales and catfish vertebrae indicate that these fish were killed in winter. Among the mammals, merycodonts (aged by their horns and dentitions) and horses (aged by dentitions) apparently died in winter also. Unlike the Green River fish, which accumulated over thousands of years, the Nebraska occurrence probably resulted from a catastrophe.

Peculiarities of seasonal changes of taxonomic structure and number of weevil-beetles (Coleoptera, Curculionidae) of herptobios in Kharkiv urbocenoses (Ukraine)

2019 ◽  
Vol 16 (1) ◽  
pp. 25-35 ◽  
Author(s):  
N.A. Komaromi ◽  
A.V. Putchkov ◽  
V.Yu. Nazarenko
Keyword(s):  
Early Summer ◽  
Taxonomic Structure ◽  
Dynamic Density ◽  
Number Of Species ◽  
Summer Maximum ◽  
Minimal Quantity ◽  
Slight Rise ◽  
Suburban Forests ◽  
The City ◽  
Increased Activity

A total of 54 species in 35 genera of Curculionidae are registered in the urbocenoses of Kharkiv city. Only three species, Exomias pellucidus, Otiorhynchus raucus and Ot. ovatus, are recorded as dominants. Some other species (Urometopus nemorum, Sciaphobus squalidus and Glocianus punctiger) are sporadically noted in some sites as subdominants. The total number of species turned out to be higher in the herpetobios of plantings at periphery (31), slightly lower in private farmlands of the city (21), parks and plantings of the center (17 each), but minimal in suburban forests (11 species). The highest quantity of specimens were observed for the plantations of the center and margins of city: nevertheless, minimal quantity of specimens was registered at parks and woods. The maximum number of species (including all cenoses) was recorded from the end of April to first decade of May (28 species). From May to the end of June 15–18 species were registered. Ten species were recorded at July, and only six species at August. A slight rise was noted from the end of August to mid-September (11 species). In biotopes where Exomias pellucidus appeared to be the monodominant, the seasonal dynamic density of weevils reached a peak at late May or early June, but the significant decline was observed from early June to July. At the sites with several dominants, two or three peaks were registered: at spring (May) and at mid-summer (end of June or beginning of July). Furthermore, the number of weevils decreased gradually, but some species of Curculionidae were rather abundant even from the end of summer to September–October. The spring increase is reasoned by high density of species in the genus Otiorhynchus; the peak in early summer (maximum) is caused by the increased activity of majority of dominant species; the autumn peak is also caused by the high number of species of the genus Otiorhynchus. The level of sex index (by the example of E. pellucidus) differed significantly at all plots. It was higher for the plantations at the periphery of the city (0.70), and it was minimal at private farmlands (0.20). Relative conjugacy of sex index and dynamic density were not observed: the maximum abundances of quantity of Curculionidae were recorded 20–30 days earlier than the maximal numbers of the sex index.

Paleontology and stratigraphy of Middle Eocene rock units in the southern Green River and Uinta Basins, Wyoming and Utah

2017 ◽  
Vol 4 ◽  
pp. 1-53 ◽  
Author(s):  
Paul Murphey ◽  
K.E. Townsend ◽  
Anthony Friscia ◽  
James Westgate ◽  
Emmett Evanoff ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Middle Eocene ◽  
Green River Basin ◽  
Green River ◽  
Scientific Exploration ◽  
History Of ◽  
Climatic History ◽  
Field Excursion ◽  
Land Mammal ◽  
Bridger Formation

The Bridger Formation is restricted to the Green River Basin in southwest Wyoming, and the Uinta and Duchesne River Formations are located in the Uinta Basin in Utah. These three rock units and their diverse fossil assemblages are of great scientific importance and historic interest to vertebrate paleontologists. Notably, they are also the stratotypes from oldest to youngest for the three middle Eocene North American Land Mammal Ages—the Bridgerian, Uintan, and Duchesnean. The fossils and sediments of these formations provide a critically important record of biotic, environmental, and climatic history spanning approximately 10 million years (49 to 39 Ma). This article provides a detailed field excursion through portions of the Green River and Uinta Basins that focuses on locations of geologic, paleontologic, and historical interest. In support of the field excursion, we also provide a review of current knowledge of these formations with emphasis on lithostratigraphy, biochronology, depositional, and paleoenvironmental history, and the history of scientific exploration.

Secretary Udall Reviews the Green River Fish Eradication Program

Copeia ◽  
1963 ◽  
Vol 1963 (2) ◽  
pp. 465 ◽  
Author(s):  
Carl L. Hubbs
Keyword(s):  
Green River ◽  
Eradication Program ◽  
River Fish

Impact of extrafloral nectar availability and plant genotype on ant (Hymenoptera: Formicidae) visitation to quaking aspen (Salicaceae)

2015 ◽  
Vol 148 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Jonathon R. Newman ◽  
Diane Wagner ◽  
Patricia Doak
Keyword(s):  
Populus Tremuloides ◽  
Late Summer ◽  
Early Summer ◽  
Quaking Aspen ◽  
Plant Genotype ◽  
Free Living ◽  
Natural Induction ◽  
Formica Fusca ◽  
Time Of Year ◽  
Nectar Availability

AbstractFor quaking aspen (Populus tremuloides Michaux; Salicaceae) the rate of extrafloral (EF) sugar secretion is increased by defoliation and decreased by drought. Although wholesale blocking of EF nectar has been shown to reduce ant (Hymenoptera: Formicidae) visitation to aspen, the effect of more subtle and realistic variations in nectar availability on ant recruitment is unknown. Working in Alaskan boreal forest (United States of America), we reduced and supplemented EF nectar availability on potted aspen ramets of three genotypes and surveyed visitation by free-living Formica fusca (Linnaeus) (Hymenoptera: Formicidae). Ants were more responsive to a subtle increase in sugar availability than to a decrease. While nectar reduction had no effect on ant visitation, nectar supplementation increased ant visitation to one aspen genotype by 70% during an early summer trial. Average ant visitation to different aspen genotypes varied during the late summer, indicating that aspen genotype can influence attractiveness to ants. We conclude that natural induction of EF secretion in response to herbivory may benefit aspen through improved ant recruitment, though the response is dependent on aspen genotype and time of year. Differences among aspen genets in attractiveness to ants could influence the relative success of genotypes, especially in settings in which aspen regenerates from seed.

scholarly journals The Uplift of Unteraargletscher at the Beginning of the Melt Season—A Consequence of Water Storage at the Bed?

1983 ◽  
Vol 29 (101) ◽  
pp. 28-47 ◽  
Author(s):  
A. Iken ◽  
H. Röthlisberger ◽  
A. Flotron ◽  
W. Haeberli
Keyword(s):  
Water Pressure ◽  
Storage System ◽  
Water Storage ◽  
High Water ◽  
Early Summer ◽  
Upward Movement ◽  
Drainage Channels ◽  
Summer Maximum ◽  
Cavity Development ◽  
The Times

Abstract Results of systematic movement studies carried out by means of an automatic camera on Unteraargletscher since 1969 are discussed together with supplementary theodolite measurements made at shorter intervals and over a longer section of the glacier. In addition to the typical spring/early summer maximum of velocity known from other glaciers, an upward movement of up to 0.6 m has been recorded at the beginning of the melt season. It was followed, after a few fluctuations of the vertical velocity, by an equal but slower downward movement which continued at an almost constant rate for about three months. Possible explanations of the uplift are discussed, the most satisfactory explanation being water storage at the bed. The observations then suggest that this storage system is efficiently connected with the main subglacial drainage channels only during times of very high water pressure in the channels. Detailed measurements showed that the times of maximum horizontal velocity coincided with the times of maximum upward velocity rather than with the times when the elevation of the surveyed poles had reached a maximum. On the basis of the hypothesis of water storage at the bed this finding means that the sliding velocity is influenced mainly by the subglacial water pressure and the actual, transient stage of cavity development, while the amount of stored water is of lesser influence.

Animal production from pasture with and without conservation for winter feeding

1957 ◽  
Vol 1957 ◽  
pp. 17-31
Author(s):  
D. E. Eyles
Keyword(s):  
Early Summer ◽  
Animal Production ◽  
Late Spring ◽  
Summer Drought ◽  
Constant Number ◽  
Seasonal Growth ◽  
Main Obstacle ◽  
Summer Grazing ◽  
Winter Feeding

The uneven seasonal growth of herbage is the main obstacle to the more efficient utilisation of grassland. There is an abundance of growth in late spring and early summer and a scarcity during a summer drought and in winter. Heavy stocking in spring followed by lighter stocking in summer is a suitable management for fattening sheep and cattle because they can be sold fat from June onwards, but a constant number of livestock has to be maintained throughout the year on many farms which carry breeding or growing animals. On these farms grassland, besides giving summer grazing, is expected to provide the bulk of the fodder for over-wintering. It is doubtful whether the results of grazing experiments which evaluate summer grazing only can be applied to these farms.

Population Dynamics and Movement Patterns of Bolam's Mouse, Pseudomys bolami, at Roxby Downs, South Australia.

1998 ◽  
Vol 20 (3) ◽  
pp. 353
Author(s):  
K.E. Moseby ◽  
J.L. Read
Keyword(s):  
Arid Zone ◽  
Sand Dunes ◽  
South Australia ◽  
Breeding Strategy ◽  
Early Summer ◽  
Ecological Data ◽  
Winter Rainfall ◽  
Land Systems ◽  
Single Night ◽  
Time Of Year

Basic ecological data were collected on Bolam's mouse, Pseudomys bolami, during a six year trapping study at Roxby Downs in northern South Australia. Pseudomys bolami inhabited mixed arid land systems in the Roxby Downs area, sheltering in the longitudinal orange sand dunes but foraging at night principally on the adjacent chenopod swales. Distances of up to 334m were traversed in a single night and recapture rates were high within trapping sessions but low between sessions suggesting wide-ranging movements and short-term residency. Dietary observations imply an omnivorous diet. Whilst the closely related P. hermannsburgensis is regarded as having an opportunistic breeding strategy, P. bolami reproduced opportunistically but also regularly in spring and early summer. Different reproductive strategies may be influenced by the latitudinal distribution of P. bolami near the southern margin of the arid-zone, where rainfall can occur at any time of year but winter rainfall is more predictable. This contrasts with P. hermannsburgensis, which inhabits more northerly arid areas where rainfall is erratic and unpredictable. There was a 10 fold fluctuation in P. bolami captures over the trapping period with numbers of P. bolami and house mice, Mus domesticus peaking 12 months after above average rains during 1992. Rodent captures remained high for two years afterwards. Although P. bolami persisted throughout the study period, M. domesticus was only present when conditions were above average. Trap success of P. bolami or M. domesticus did not vary between the five sub habitats at the 1 ha study site. However, trap success of P. bolami was positively related to vegetation cover, particularly cover of low bluebush, Maireana astrotricha. Maireana astrotricha may be important in providing both food and cover for P. bolami, a scenario consistent with the utilisation of spinifex, Triodia spp. by P. hermannsburgensis in the northern arid-zone. Past over- grazing of chenopod shrublands may have reduced cover and contributed to the suggested decline in the distribution of P. bolami.

Grass Growth in Response to Time of Rainfall and Season Along a Climate Gradient in Australian Rangelands.

1997 ◽  
Vol 19 (1) ◽  
pp. 95 ◽  
Author(s):  
BH Walker ◽  
FR Mcfarlane ◽  
JL Langridge
Keyword(s):  
Soil Moisture ◽  
Perennial Grass ◽  
Management Strategies ◽  
The Other ◽  
Green Leaf ◽  
Grass Species ◽  
Seasonal Growth ◽  
Available Soil Moisture ◽  
Time Of Year ◽  
Grass Growth

Percentage green leaf and height of the major perennial grass species was estimated fortnightly at six locations along a rainfall predictability gradient from Katherine (most predictable) to Lake Mere near Cobar (aseasonal), and regressed on estimated plant available soil moisture (PASM) and time of year (T). Green leaf is more strongly related to T at Katherine and to PASM at Lake Mere with the other sites in-between. Differences between species in terms of seasonal growth phenology were minor, at all sites, and there were no meaningful patterns in percentage contributions by the species to sward biomass. A strong inter-seasonal rainfall pattern over the period of the study may have masked phenological differences between species, but it is also possible that changes in species composition very soon after livestock were introduced resulted in a decline in phenological differentiation. Whatever the reason, the differences observed in this study would ~ot warrant their use in the formulation of management strategies.

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