Browsing by Author "Nascimbene, Paul C."
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Item Biological inclusions in amber from the Paleogene Chickaloon Formation of Alaska. (American Museum novitates, no. 3908)(American Museum of Natural History., 2018-09-28) Grimaldi, David A.; Sunderlin, David.; Aaroe, Georgene A.; Dempsky, Michelle R.; Parker, Nancy E.; Tillery, George Q.; White, Jaclyn G.; Barden, Phillip.; Nascimbene, Paul C.; Williams, Christopher J. (Christopher James), 1970-The Chickaloon Formation in south-central Alaska contains rich coal deposits dated very close to the Paleocene-Eocene boundary, immediately beneath which occur dispersed nodules of amber along with abundant remains of Metasequoia, dicots, and monocots. The nodules are small (less than 10 mm in length), nearly 10,000 of which were screened, yielding several inclusions of fungi and plant fragments, but mostly terrestrial arthropods: 29 specimens in 10 orders and 13 families. The fungi include resinicolous hyphae and a dark, multiseptate hyphomycete. Plants include wood/bark fragments and fibers, and the microphylls of a bryophyte (probably a moss, Musci). Among the arthropods are arachnids: mites (Acari: Oribatida), Pseudoscorpionida, and the bodies and a silken cocoon of spiders (Araneae). Insecta include Blattodea, Thysanoptera, Hemiptera (Heteroptera and Aphidoidea), Coleoptera (Dermestidae: Megatominae), Trichoptera, Diptera (Chironomidae: Tanypodinae), and Hymenoptera (Formicidae: Formicinae). Nymphal aphids predominate (65% of the arthropod individuals), which were probably feeding on the source tree, likely Metasequoia. There is a bias in preservation toward small arthropods (mean body length 0.75 mm) that are surface-dwelling (nonwinged) stages and taxa. Chickaloon amber contains the most northerly fossil records of pseudoscorpions, thrips, Dermestidae, and Cenozoic ants and mites, so the deposit is contributing unique data on high-latitude paleodiversity of the Paleogene hothouse earth.Item Coniopterygidae (Neuroptera, Aleuropteryginae) in amber from the Eocene of India and the Miocene of Hispaniola. (American Museum novitates, no. 3770)(American Museum of Natural History., 2013-02-22) Grimaldi, David A.; Engel, Michael S.; Nascimbene, Paul C.; Singh, Hukam.The genus Spiloconis Enderlein is comprised of six Recent Asian and Pacific species, ranging from Sri Lanka (and possibly Madagascar) in the west to eastern Australia and Fiji in the east. Two species previously described in Miocene amber from the Dominican Republic, Spiloconis glaesaria Meinander and S. oediloma Engel and Grimaldi, are redescribed for some details. Spiloconis eominuta Grimaldi and Engel, new species, is described in earliest Eocene Cambay amber from Gujarat, India, which has well-preserved male terminalia. Neoconis paleocaribis Grimaldi and Engel, new species, is described from Dominican amber; this Recent genus is known from the southern United States and neotropics. The fossil Spiloconis may have significant biogeographic implications, but definitive determination of this requires a phylogenetic analysis of the 16 Recent genera in the monophyletic subfamily Aleuropteryginae. A Dominican amber-Australasian distribution pattern is known for 18 genera of insects in myriad orders (including Spiloconis), which are briefly reviewed.Item Fossiliferous Cretaceous amber from Myanmar (Burma) : its rediscovery, biotic diversity, and paleontological significance. American Museum novitates ; no. 3361(New York, NY : American Museum of Natural History, 2002) Grimaldi, David A.; Engel, Michael S.; Nascimbene, Paul C.Amber from Kachin, northern Burma, has been used in China for at least a millennium for carving decorative objects, but the only scientific collection of inclusion fossils, at the Natural History Museum, London (NHML), was made approximately 90 years ago. Age of the material was ambiguous, but probably Cretaceous. Numerous new records and taxa occur in this amber, based on newly excavated material in the American Museum of Natural History (AMNH) containing 3100 organisms. Without having all groups studied, significant new records and taxa thus far include the following (a † refers to extinct taxa): For Plants: An angiosperm flower (only the third in Cretaceous amber), spores and apparent sporangia of an unusual but common fungus, hepatophyte thalli and an archegoniophore of Marchantiaceae, and leafy shoots of Metasequoia (Coniferae). Metasequoia is possibly the source of the amber. For Animals: Mermithidae and other Nematoda; the oldest ixodid tick (a larval Amblyomma); bird feathers; and the only Mesozoic record of the Onychophora ('velvet' worms), described as †Cretoperipatus burmiticus, n. gen., n. sp. (Peripatidae). Poinar's classification of the Onychophora is substantially revised. Still largely unstudied, the fauna of mites (Acari) and spiders (Araneae) appears to be the most diverse ones known for the Mesozoic. For Insecta: Odonata indet. (wing fragment); Plecoptera indet.; new genera of Dermaptera, Embiidina, and Zoraptera (the latter two as the only definitive Mesozoic fossils of their orders). Within Hemiptera, there are primitive new genera in the Aradidae, Hydrometridae, Piesmatidae, Schizopteridae, and Cimicomorpha (Heteroptera), as well as in †Tajmyraphididae (Aphidoidea), and †Protopsyllidiidae. An adult snakefly (Raphidioptera: †Mesoraphidiidae) is the smallest species in the order, and new genera occur in the Neuroptera: Coniopterygidae, Berothidae, and Psychopsidae, as well as larvae of apparent Nevrorthidae. Coleoptera are largely unstudied, but are probably the most diverse assemblage known from the Cretaceous, particularly for Staphylinidae. An adult lymexylid, the most primitive species of Atractocerus, is the first Mesozoic record of the family. In Hymenoptera there are primitive ants (Formicidae: Ponerinae n. gen., and †Sphecomyrma n.sp (Sphecomyrminae)), the oldest record of the Pompilidae, and significant new records of †Serphitidae and †Stigmaphronidae, among others. Diptera are the most diverse and abundant, with the oldest definitive Blephariceridae and mosquito (Culicidae), as well as new genera in the Acroceridae, Bibionidae, Empidoidea; a new genus near the enigmatic genus Valeseguya, and an unusual new genus in the †Archizelmiridae. †Chimeromyia (Diptera: Eremoneura), known previously in ambers from the Lower Cretaceous, is also represented. The stratigraphic distribution of exclusively Mesozoic arthropods in Burmese amber is reviewed, which indicates a probable Turonian-Cenomanian age of this material (90-100 Ma). Paleofaunal differences between the NHML and AMNH collections are discussed, as is the distinct tropical nature of the original biota. Burmese amber probably harbors the most diverse biota in amber from the Cretaceous, and one of the most diverse Mesozoic microbiotas now known.Item Variation in the deterioration of fossil resins and implications for the conservation of fossils in amber. (American Museum novitates, no. 3734)(American Museum of Natural History., 2012-02-23) Bisulca, Christina.; Nascimbene, Paul C.; Elkin, Lisa, 1966-; Grimaldi, David A.The deterioration of fossil resins (crazing, cracking, and darkening) was investigated by comparing the effects of one year of accelerated aging--specifically intensive exposure to light, heat, and fluctuating humidity, both individually and in combination--on samples from several natural resin deposits. These included two Cretaceous ambers (from Myanmar (Burma) and central New Jersey), two Tertiary ambers (from the Baltic and the Dominican Republic), and Holocene copal from Zanzibar. The five resins were chosen for their disparate ages and botanical origins (and thus chemical and physical properties), as well as their paleontological significance. In all cases, pronounced deterioration occurred under combined exposure to light and fluctuating humidity, based on surface crazing and a decrease in absorbance of light in the UV region (360-400 nm). While crazing did not visibly occur in cases of fluctuating humidity in dark conditions, or UV exposure alone, spectrophotometric evidence indicates that some deterioration did take place. Yellowing after exposure to elevated temperatures occurred in all samples tested, with the exception of Burmese amber. All four true ambers exhibited a decrease in UV absorbance after exposure to heat (while copal actually showed an increase). The samples from the five deposits represent three chemical subclasses of fossil resins, and each of the resins reacted differently to the various aging conditions, with New Jersey amber particularly unstable. Based on these results, amber collections should be stored in an environment with stable humidity, relatively low heat, and minimal exposure to light. Anoxic sealing and storage, and particularly embedding amber samples in a high-grade epoxy, may be beneficial, and further investigation is indicated.