Remarks on the age of Dominican amber

2019 ◽  
Vol 2 (3) ◽  
pp. 236-240 ◽  
Author(s):  
MANUEL A. ITURRALDE-VINENT ◽  
ROSS D.E. MACPHEE
Keyword(s):  
Dominican Republic ◽  
Analytical Approach ◽  
Late Eocene ◽  
Early Pleistocene ◽  
High Quality ◽  
Lower Miocene ◽  
Dominican Amber ◽  
Geological Age ◽  
Best Fit ◽  
Age Estimates

Amber from the Dominican Republic is famous for the high quality, frequency, and diversity of organic fossils found as inclusions in this mineral (Grimaldi, 1996; Poinar & Poinar, 1999). However, its geological age of origin remains a continuing source of controversy. Over the years a wide variety of age estimates have been made for occurrences of Dominican amber, ranging from Cretaceous (Brouwer & Brouwer, 1982) to Late Eocene (Lambert et al., 1985) to pre-Lower Miocene (Baroni-Urbani & Saunders, 1982). Some authors have also favored a spread of ages that covers much of the Cenozoic (e.g., 40 or 45 Ma to 15 Ma; Poinar & Poinar, 1999). Iturralde-Vinent & MacPhee (1996) attempted to resolve discrepancies in age assignments by taking a multi-pronged analytical approach which yielded a best-fit estimate of mid-Miocene age (20–15 Ma). This estimate has been widely accepted and additionally corroborated by new studies (Iturralde-Vinent, 2001; Ortega-Ariza et al., 2015). However, Braga et al. (2012) have challenged the assessment of Iturralde-Vinent & MacPhee (1996) by arguing for a Pliocene–early Pleistocene date for the amber-bearing Yanigua Formation. Here we address the sources of disagreement and suggest a solution.

A fossil Aspergillus from Eocene Dominican amber

1988 ◽  
Vol 62 (01) ◽  
pp. 141-143 ◽  
Author(s):  
Gerard M. Thomas ◽  
George O. Poinar
Keyword(s):  
Dominican Republic ◽  
Fossil Species ◽  
First Report ◽  
Dominican Amber ◽  
Eocene Amber

A sporulating Aspergillus is described from a piece of Eocene amber originating from the Dominican Republic. The Aspergillus most closely resembles a form of the white spored phase of Aspergillus janus Raper and Thom. This is the first report of a fossil species of Aspergillus.

scholarly journals A male of the bee genus Agapostemon in Dominican amber (Hymenoptera: Halictidae)

2013 ◽  
pp. 1 ◽  
Author(s):  
Michael S. Engel ◽  
Laura C.V. Breitkreuz
Keyword(s):  
New Species ◽  
Dominican Republic ◽  
West Indian ◽  
The West ◽  
Single Male ◽  
Fossil Species ◽  
Dominican Amber ◽  
Modern Species

Thefirst fossil species of the caenohalictine bee genus Agapostemon Guérin-Méneville (Halictinae: Caenohalictini:Agapostemonina) is described and figured from a single male preserved in EarlyMiocene (Burdigalian) amber from the Dominican Republic.  Agapostemon (Notagapostemon) luzziiEngel & Breitkreuz, new species, is compared with modern species and isnoteworthy for the absence of metafemoral modifications [in this regardplesiomorphically resembling the West Indian A. kohliellus (Vachal)and A. centratus (Vachal)], form of the head and protibial antennalcleaner, integumental sculpturing, and male terminalia, the latter of which arefortunately exposed and cleared.  Briefcomments are made on the affinity of the species to others in the West Indiesand surrounding regions as well as possible biogeographic implications.

Remarkable stasis in some Lower Tertiary parasitoids: descriptions, new records, and review of Strepsiptera in the Oligo-Miocene amber of the Dominican Republic

1993 ◽  
Vol 24 (1) ◽  
pp. 31-41 ◽  
Author(s):  
David Grimaldi ◽  
Jeyaraney Kathirithamby
Keyword(s):  
Dominican Republic ◽  
Lower Cretaceous ◽  
New Record ◽  
New Records ◽  
Dominican Amber ◽  
Lower Tertiary ◽  
New Findings ◽  
History Of

AbstractKathirithamby, J. & Grimaldi, D.: Remarkable stasis in some Lower Tertiary parasitoids: descriptions, new records, and review of Strepsiptera in the Oligo-Miocene amber of the Dominican Republic. Ent. scand. 24: 31-41. Copenhagen, Denmark. April 1993. ISSN 0013-8711. 25-30 million years of parasite stasis is recorded in amber from the Dominican Republic, by the finding of a species of strepsipteran morphologically indistinguishable from Bohartilla melagognatha Kinzelbach, 1969 (Bohartillidae), and two species very close to Caenocholax fenyesi (Pierce 1909) (Myrmecolacidae). A new record is made of a species previously described from Dominican amber, Myrmecolax glaesi Kinzelbach, 1983. The history of the Tertiary strepsipteran fauna is discussed. Minimal ages of taxa are extrapolated based on these amber and other fossils, higher-level cladistic relationships, and fossil dating of major host groups. These new findings are consistent with Kinzelbach's hypotheses of an ancient, Lower Cretaceous/Jurassic origin of the Strepsiptera.

Two new genera, Mycophoris gen. nov., (Orchidaceae) and Synaptomitus gen. nov. (Basidiomycota) based on a fossil seed with developing embryo and associated fungus in Dominican amber

Botany ◽  
2017 ◽  
Vol 95 (1) ◽  
pp. 1-8 ◽  
Author(s):  
George Poinar
Keyword(s):  
Dominican Republic ◽  
Orchid Mycorrhiza ◽  
New Genera ◽  
Dominican Amber ◽  
Single Piece ◽  
Embryo Cells ◽  
Orchid Seed

Aside from a variety of arthropod remains, Dominican amber also contains an assortment of leaves, flowers, and seeds. An orchid seed with a developing embryo in Dominican amber is described as Mycophoris elongatus gen. et sp. nov. Cells of the developing embryo were infected with a fungus that is described as Synaptomitus orchiphilus gen. et sp. nov. The fungus represents a Basidiomycota that was probably serving as an orchid mycorrhiza (OM), based on its morphology and the formation of pelotons inside infected embryo cells. The single piece of amber containing the fossil was obtained from a mine in the Dominican Republic and is at least 15–20 Ma.

CRICKETS (GRYLLOPTERA: GRYLLOIDEA) IN DOMINICAN AMBER

1994 ◽  
Vol 126 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Vernon R. Vickery ◽  
George O. Poinar
Keyword(s):  
New Species ◽  
Dominican Republic ◽  
New Genera ◽  
Dominican Amber ◽  
Extant Genus ◽  
Ability To Regenerate

AbstractTwenty-eight pieces of amber from the Dominican Republic were studied. These pieces, 22–40 million years old, contain 29 cricket specimens as inclusions. Six new species in the Trigonidiidae: Trigonidiinae are described, one in the extant genus Anaxipha (A. dominica) and in three related new genera: Proanaxipha (P. latoca and P. bicolorata), Abanaxipha (A. longispina and A. incongrua), and Grossoxipha (G. yaque). One specimen is described in the Mogoplistidae: Mogoplistinae in the extant genus Ornebius (O. ambericus). The presence of these specimens in amber proves that utilization of the boreal habitat is of long standing. Disparity in the size of the hind legs of one specimen indicates that crickets may once have had the ability to regenerate lost limbs.

Development of an Analytical Model for the Static and Dynamic Transmission Error Calculation: Validation on a Single Vehicle Gear Vibration Test Bench

2000 ◽  
Author(s):  
Fabrizio Cricenti ◽  
Claus-Hermann Lang ◽  
Domenico Paradiso
Keyword(s):  
Load Distribution ◽  
Analytical Approach ◽  
Test Bench ◽  
Transmission Error ◽  
Noise Levels ◽  
High Quality ◽  
Dynamic Transmission Error ◽  
Single Vehicle ◽  
Quality And Reliability ◽  
Very High

Abstract Automotive companies are being challenged when they seek to guarantee very high quality and reliability levels for their products. Customers may complain about comfort and various other concerns such as noise generated by a certain component. Analytical, numerical simulation and testing are used to understand how certain modifications to the product can affect the excited noise level. This paper presents an analytical approach used in order to predict noise levels coming from an engaged vehicle gear pair. This is done by evaluating the static and dynamic transmission error with load distribution on the teeth engaged for the different values of micro-geometric teeth modifications. Comparing the analytical and experimental results shows that both factors can be extremely linked with noise generated by two mating gears.

Slow life-history traits of a neritic predator, the bronze whaler (Carcharhinus brachyurus)

2017 ◽  
Vol 68 (3) ◽  
pp. 461 ◽  
Author(s):  
Michael Drew ◽  
Paul Rogers ◽  
Charlie Huveneers
Keyword(s):  
Life History ◽  
Growth Parameters ◽  
Isolated Populations ◽  
Life History Characteristics ◽  
Regional Estimates ◽  
Males And Females ◽  
Size At Age ◽  
Slow Growing ◽  
Best Fit ◽  
Age Estimates

Intra-species plasticity in the life-history characteristics of sharks leads to the need for regional estimates to accurately determine resilience to anthropogenic effects. The present study provides the first length-at-age, growth and maturity estimates for the bronze whaler (Carcharhinus brachyurus) from southern Australia. Age estimates were obtained from vertebral sections of 466 individuals spanning 50–308-cm total length. Maximum estimates of age for males and females were 25 and 31 years respectively. The three-parameter logistic model for females (L∞=308cm LT, k=0.15, α=742) and for males (L∞=317cm LT, k=0.13, α=782) provided the best fit to the size at age data. Males matured at a similar age (16 years), but smaller size than females (224v. 270cm LT). Growth parameters and age-at-maturity estimates were similar to those for genetically isolated C. brachyurus populations, and the sympatric dusky shark (C. obscurus). The southern Australian C. brachyurus population is long-lived, slow growing and late maturing. These growth parameters are needed to undertake demographic analyses to assess the resilience of C. brachyurus to fishing, and provide an example of a wide-ranging elasmobranch with similar life-history characteristics across isolated populations.

Improved Best Fit Algorithm for Billet Stacking Problem

2014 ◽  
Vol 488-489 ◽  
pp. 1235-1238
Author(s):  
Guang Jing Dong ◽  
Tie Ke Li ◽  
Bai Lin Wang ◽  
Liang Bai ◽  
Shao Yun Xu
Keyword(s):  
Rolling Mill ◽  
Computational Experiments ◽  
High Quality ◽  
Problem Instances ◽  
Best Fit

Aiming at billet stacking problem of the rolling mill, an IBF algorithm is used to assign the billet to the warehouse positions. The utilization of non-empty warehouse positions and shuffles are considered in the algorithm. Computational experiments demonstrate that the proposed algorithm is feasible and effective, competitive and able to find more high-quality solutions for problem instances than artificial method.

scholarly journals I. Contributions to the history of the pleiocene and pleistocene deer. Part I. Cervus verticornis, Cervus savini

1885 ◽  
Vol 38 (235-238) ◽  
pp. 345-345 ◽  
Keyword(s):  
Old Age ◽  
Large Series ◽  
The Other ◽  
Early Pleistocene ◽  
Geological Age ◽  
History Of ◽  
The One

The numerous cervine remains which occur in the various collections in Britain and on the Continent have been studied by the author for the last twenty-five years, and in this communication two species, the one hitherto ill-defined, and the other new to science, have been described. The first, or Cervus verticornis , Dawkins, remarkable for the singular forward and downward curvature of the first tine, is represented by a large series of skulls and antlers, which enable the author to define the changes in antler-form from youth to old age, as well as to relegate it to the division of deer with palmated antlers, and to establish its geological age to be Pleiocene, and early Pleistocene, in Norfolk and Suffolk.

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