95 research outputs found

    Taphonomy of fossilized resins: determining the biostratinomy of amber

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    Comparing the maturity of fossilized resins with that of their enclosing bedrock can provide information on the maturity, relative age and biostratinomy of amber and copal. A method to determine this is presented here with examples of amber and copal from the Dominican Republic. Maturity of the bedrock was determined by vitrinite reflection and that of the fossilized resin by FTIR analysis. Vitrinite oxidation values showed maturity states corresponding to lignite and sub-bituminous coal ranks. While the samples from some mines demonstrated that the maturities of the rock and fossilized resin were syngenetic, other samples indicated that recycling of the amber may have occurred. Darkening of the amber (from yellow to red) was correlated with increased oxidation / weathering. This method can be a useful tool for understanding the biostratinomy of fossilized resins

    Halophilanema prolata n. gen., n. sp. (Nematoda: Allantonematidae), a parasite of the intertidal bug, Saldula laticollis (Reuter)(Hemiptera: Saldidae) on the Oregon coast

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    This is the publisher’s final pdf. The published article is copyrighted by BioMed Central and can be found at: http://www.biomedcentral.com/.Background: It is rare to find terrestrial nematode lineages parasitizing arthropods inhabiting the intertidal or\ud littoral zone of the oceans. During an ecological study along the Oregon dunes, an allantonematid nematode\ud (Tylenchomorpha: Allantonematidae) was discovered parasitizing the intertidal shore bug, Saldula laticollis (Reuter)\ud (Hemiptera: Saldidae). This shore bug is adapted to an intertidal environment and can survive short periods of\ud submergence during high tides. The present study describes the nematode parasite and discusses aspects of its\ud development, ecology and evolution.\ud Methods: Adults and last instar nymphs of S. laticollis (Hemiptera: Saldidae) were collected from the high intertidal\ud zone among clumps of Juncus L. (Juncaceae) plants at Waldport, Oregon on October 3, 2011. The bugs were\ud dissected in 1% saline solution and the nematodes killed in 1% Ringers solution and immediately fixed in 5%\ud formalin (at 20°C). Third stage juveniles removed from infected hosts were maintained in 1% saline solution until\ud they matured to the adult stage, molted and mated.\ud Results: Halophilanema prolata n. gen., n. sp. (Nematoda: Allantonematidae) is described from last instar nymphs\ud and adults of the intertidal bug, Saldula laticollis on the Oregon coast. The new genus can be distinguished from\ud other genera in the Allantonematidae by a stylet lacking basal knobs in both sexes, an excretory pore located\ud behind the nerve ring, ribbed spicules, a gubernaculum, the absence of a bursa and the elongate-tubular shape of\ud the ovoviviparous parasitic females. Studies of the organogenesis of Halophilanema showed development to third\ud stage juveniles in the uterus of parasitic females. Maturation to the free-living adults and mating occurred in the\ud environment. The incidence of infection of S. laticollis ranged from 0% to 85% depending on the microhabitat in\ud the intertidal zone.\ud Conclusions: Based on the habitat and morphological characters, it is proposed that Halophilanema adapted a\ud parasitic existence fairly recently, evolutionarily speaking. It was probably a free-living intertidal or shore nematode\ud that fed on microorganisms, especially fungi, in the intertidal habitat and became parasitic after saldids entered the\ud environment. Halophilanema represents the first described nematode parasite of an intertidal insect

    Paleoculicis minututs (Diptera: Culicidae) n. Gen., n. Sp., from Cretaceous Canadian amber, with a summary of described fossil mosquitoes

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    A new genus and species of fossil mosquito (Diptera: Culicidae) is described from Canadian Cretaceous amber, thus providing the first undeniable record of this group from the Cretaceous Period. Paleoculicis minutus n.gen., n.sp. can be separated from extant culicids by features of the head, thorax, and abdomen. Paleoculicis has closer affinities to the Culicinae than to the Anophelinae or Toxorhynchitinae. If P. minutus fed on blood, a range of ve rtebrates (including dinosaurs) were potential hosts some 79 million years ago. A review of previous descriptions of fossil mosquitoes is presented. Many cannot be confidently assigned to the Culicidae, while others are extant species in copal. Only a minority of them can be regarded as true Culicidae, all of which are reported from Tertiary deposits.Se describe un nuevo género y especie de mosquito (Diptera: Culicidae) del ámbar del Cretácico de Canadá, que aporta el primer registro irrefutable de este grupo en el período Cretácico. Paleoculicis minutus n.gen., n.sp. puede ser diferenciado de los culícidos existentes por caracteres de la cabeza, tórax y abdomen. Paleoculicis tiene estrechas afinidades con los Culicinae, así como con los Anophelinae o los Tox o r hynchitinae. Si Paleoculicis minutus se alimentaba de sangre, un amplio grupo de vertebrados (incluidos los dinosaurios) fueron huéspedes potenciales hace unos 79 millones de años. Se presenta la revisión de los mosquitos fósiles descritos con anterioridad. Algunos no pueden ser asignados de manera segura a los Culicidae, mientras que otras son especies actuales encontradas en el copal. Sólo una minoría de ellos pueden ser considerados como verdaderos Culicidae, los cuales se relacionan con depósitos del Terciario

    Upper Eocene robber flies of the genus Ommatius (Diptera: Asilidae) in Dominican amber

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    Ommatius fimbriatus and O. subtus are based upon four specimens embedded in Dominican amber from the El Mamey Formation in the Dominican Republic. The amber is from the Lower Oligocene - Upper Eocene, originating between 25 and 40 million years ago. The specimens are the first reported fossils of Ommatius. Both species are described and compared with modern species. Significant characters are illustrated and/or photographed

    Chronogaster troglodytes sp n (Nemata, Chronogasteridae) from Mobile cave, with a review of cavernicolous nematodes

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    Summary -Chronogaster lroglodytes sp. n. (Nemata : Chronogasteridae) is described as the first true cavernicolous nematode which was recovered from Movile Cave in Romania. This species is adapted for survival in floating fungal mats growing in hydrogen sulfide-rich thermomineral waters. Populations are composed of hermaphroditic females which feed on bacteria associated with the fungal mats. A review of cavernicolous nematodes, and their relationship to epigean freshwater and soil forms, is presented
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