Consequences of elevated temperature and pCO2 on insect folivory at the ecosystem level: perspectives from the fossil record

Paleoecological studies document the net effects of atmospheric and climate change in a natural laboratory over timescales not accessible to laboratory or ecological studies. Insect feeding damage is visible on well‐preserved fossil leaves, and changes in leaf damage through time can be compared to environmental changes. We measured percent leaf area damaged on four fossil leaf assemblages from the Bighorn Basin, Wyoming, that range in age from 56.1 to 52.65 million years (Ma). We also include similar published data from three US sites 49.4 to ~45 Ma in our analyses. Regional climate was subtropical or warmer throughout this period, and the second oldest assemblage (56 Ma) was deposited during the Paleocene–Eocene Thermal Maximum (PETM), a geologically abrupt global warming event caused by massive release of carbon into the atmosphere. Total and leaf‐chewing damage are highest during the PETM, whether considering percent area damaged on the bulk flora, the average of individual host plants, or a single plant host that occurs at multiple sites. Another fossil assemblage in our study, the 52.65 Ma Fifteenmile Creek paleoflora, also lived during a period of globally high temperature and pCO₂, but does not have elevated herbivory. Comparison of these two sites, as well as regression analyses conducted on the entire dataset, demonstrates that, over long timescales, temperature and pCO₂ are uncorrelated with total insect consumption at the ecosystem level. Rather, the most important factor affecting herbivory is the relative abundance of plants with nitrogen‐fixing symbionts. Legumes dominate the PETM site; their prevalence would have decreased nitrogen limitation across the ecosystem, buffering generalist herbivore populations against decreased leaf nutritional quality that commonly occurs at high pCO₂. We hypothesize that nitrogen concentration regulates the opposing effects of elevated temperature and CO₂ on insect abundance and thereby total insect consumption, which has important implications for agricultural practices in today's world of steadily increasing pCO₂.     

中国境内始舌齿鱼(Eohiodon)的发现——兼论骨舌鱼类的分布

本文记述了产自苏北沭阳阜宁群上部的一始舌齿鱼,依据它在外形、鼻骨及尾部结构上与始舌齿鱼现有种的区别,将它定为一新种:沭阳始舌齿鱼(Eohiodon shuyangensis ,sp.nov.)。同时,本文对骨舌鱼类的历史动物地理学问题作了尝试性的分析。     

新疆三个泉地区一中始新世鸟化石

本文记述了产自新疆三个泉地区早第三纪鹳形目鸟类一新属——始鹳属(Eociconia gen.nov.)这是早第三纪鹳形目在我国的首次记录。化石出自依希白拉组,同时发现的还有不少哺乳动物。     

河南淅川核桃园组的低等四足类动物群

<正> Since 1920's, abundant fossil mammals have been collected from the Middle Eocene Hetaoyuan Formation, Xichan, Henan Province. On the contrary, only two reptile remains from these continental deposits have been reported——a turtle, Sinohadrianus sichuanensis Ping, 1929, and a crocodile Pristichampsus aff. P. rollinati identified on the basis of several ziphodont teeth (Chow et al., 1973).     

Dispersed cuticles from the Eocene of North America

KOVACH, W. L. & DILCHER, D. L., 1984. Dispersed cuticles from the Eocene of North America. Macerations of organic-rich clay from the Claiborne Formation (Middle Eocene) of Tennessee have yielded a wide variety of well-preserved dispersed cuticles. Details of the epidermal cell patterns, arrangement of the stomata1 complex, trichomes and trichome attachment have made possible the association of some dispersed cuticles with leaf types known from this formation which have similar cuticle, and with modern families. All dispersed cuticles are classified in a morphologic system. Through both our own work and a review of previous investigations we have found that distinct dispersed cuticle types can be recognized and may be used biostratigraphically to characterize geologic strata, palaeo-ecologically to provide insights into environmental reconstruction, and systematically to follow the history of certain taxa.     

FOSSIL LAGOMORPHS (MAMMALIA) FROM THE HETAOYUAN EOCENE OF XICHUAN, HENAN

<正> Among the fossil materials collected from the lower part of the Hetaoyuan Formation, exposed at Shipigou (namely Pishigou) of Xichuan County, Henan, are some specimens of the primitive lagomorphs. A left mandibular fragment of them was recovered by Lei, one of us, and is housed in the Yichang Institute of Geology and Mineral Resources, Ministry of Geology. Other isolated cheek teeth were got by means of screen-washing in the winter of 1984. In this paper these Eocene lagomorph fossils are described, and the homologies of the upper cheek tooth patterns of lagomorphs are discussed.     

湖南对锥齿兽科(Didymoconidae)一新属及有关地层的讨论

湘掠兽是我国下始新统中新发现的一种对锥齿兽类,与北美早始新世怀俄明兽(Wyolestes)比较相近。依形态和共生动物群的分析,其时代可能是早始新世早期。从有关剖面观察和追溯,其层位大致相当于栗木坪组。根据我国地层规范的规定,原岭茶组一名应予放弃,建议仍使用栗木坪组一名,以示衡阳盆地含哺乳动物化石的层位。     

The last meal of an Eocene pollen-feeding fly

1. Download : Download high-res image (347KB)
2. Download : Download full-size image

     

The first evidence of an infectious disease in early penguins

Traces of skeletal response to trauma are poorly documented for early (i.e. Paleogene, 66–23 Ma) penguins (Sphenisciformes) and infectious diseases that afflicted these seabirds have not been previously put on record. We report osteomyelitis (OM), typically a bacterial infection of bone, in a proximal pedal phalanx of a ‘giant’ penguin from the Eocene (56–34 Ma) of West Antarctica. Osteomyelitis had apparently complicated healing of a fracture. The injury left an oblique scar within the proximal aspect of the plantar surface, resulting in deformation of the articular surface. The recognised evidence of OM includes characteristic periosteal reaction as well as focal bone-loss and necrosis.