Nature：古昆虫strashilid并不是恐龙身上的跳蚤

由于化石标本极少和一些新颖的特点，来自侏罗纪的strashilid化石昆虫过去一般被认为是飞龙或有羽毛恐龙身上类似跳蚤的寄生虫。

来自中国侏罗纪中期距今大约1.65亿年的13个新标本的发现彻底改变了这一观点。这些像螯一样、曾被认为是用来向寄主身上附着的腿被发现只见于雄性，更可能是被用来在交配过程中抓雌性的。被认为适于吸血的口器在成年个体中已退化。而且，一些标本还有翅膀和鳃。看来，成年strashilid是水生的或两栖的，在水中出现和交配之后便使自己的翅膀脱落了。

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Amphibious flies and paedomorphism in the Jurassic period

Nature, 07 March 2013 | doi: 10.1038/nature11898

The species of the Strashilidae (strashilids) have been the most perplexing of fossil insects from the Jurassic period of Russia and China. They have been widely considered to be ectoparasites of pterosaurs or feathered dinosaurs, based on the putative presence of piercing and sucking mouthparts and hind tibio-basitarsal pincers purportedly used to fix onto the host’s hairs or feathers. Both the supposed host and parasite occur in the Daohugou beds from the Middle Jurassic epoch of China (approximately 165 million years ago). Here we analyse the morphology of strashilids from the Daohugou beds, and reach markedly different conclusions; namely that strashilids are highly specialized flies (Diptera) bearing large membranous wings, with substantial sexual dimorphism of the hind legs and abdominal extensions. The idea that they belong to an extinct order is unsupported, and the lineage can be placed within the true flies. In terms of major morphological and inferred behavioural features, strashilids resemble the recent (extant) and relict members of the aquatic fly family Nymphomyiidae. Their ontogeny are distinguished by the persistence in adult males of larval abdominal respiratory gills, representing a unique case of paedomorphism among endopterygote insects. Adult strashilids were probably aquatic or amphibious, shedding their wings after emergence and mating in the water.