Insects from the Upper Miocene Grubstake Formation of Alaska
Insects from the Upper Miocene Grubstake Formation of Alaska
复制标题
阿拉斯加上中新世 Grubstake 地层的昆虫
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
D. Triplehorn
中科院分区：
文献类型：
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作者：
D. Grimaldi;D. Triplehorn
摘要在阿拉斯加中部Suntrana Creek中新统上部Grubstake组弱固结湖相页岩中发现了保存完好的昆虫翅膀化石。直接覆盖火山灰的40 Ar/39 Ar测年表明，其年龄略高于6.7 ± 0.1 Ma，即白令陆桥开通前约100万年。这些昆虫包括蚂蚁的四个属和两个亚科（膜翅目：蚁科：Myrmicinae和Dolichoderinae）、姬蜂科的一个种（膜翅目：姬蜂科）、蝇的三个属和科（双翅目：摇蚊科[genus indet.]，Bibionidae [Bibio]和Lonchaeidae [Dasiops]），以及仙茅和步甲的鞘翅。现存的蝇类和可能的姬蜂的分布包括Suntransa周围的北纬度地区。这些蚂蚁属于现存的属Dolichoderus或Tapinoma（Dolichoderinae），Solenopsis或Erebomyrma（Myrmicinae），以及Veromessor和Novomessor（Myrmicinae），表明广泛的地理收缩到今天北美更南的纬度。这些发现与阿拉斯加苏厄德半岛中新世最上层（5.7 Ma）的一个稍年轻的存款的证据是一致的。气候变化和陆桥对各种昆虫类群的扩散的差异影响的影响进行了讨论。
Abstract Well-preserved insect wings are reported in weakly consolidated lacustrine shale from the Grubstake Formation, Upper Miocene of Suntrana Creek, central Alaska. 40Ar/39Ar dating of an immediately overlying volcanic ash indicates an age of slightly more than 6.7 ± 0.1 Ma, or approximately one million years before the opening of the Bering land bridge. The insects include four genera and two subfamilies of ants (Hymenoptera: Formicidae: Myrmicinae and Dolichoderinae), a species of Ichneumonidae (Hymenoptera), three genera and families of flies (Diptera: Chironomidae [genus indet.], Bibionidae [Bibio] and Lonchaeidae [Dasiops]), and the elytra of curculionid and carabid beetles. Extant distributions of the flies and possibly the ichneumonid include northerly latitudes around Suntrana. The ants are attributable to the extant genera Dolichoderus or Tapinoma (Dolichoderinae), Solenopsis or Erebomyrma (Myrmicinae), as well as Veromessor and Novomessor (Myrmicinae), indicating extensive biogeographic contraction to more southern latitudes of North America today. These finds are consistent with evidence from a slightly younger deposit from the uppermost Miocene (5.7 Ma) of the Seward Peninsula, Alaska. Implications are discussed regarding the differential effects of climate change and land bridges on the dispersal of various insect taxa.