| Stag beetles belong to one of primitive families in Scarabaeoidea (Coleoptera). Most of them habituated in forest. Larvae of them live in rotten logs and fed off the humus so that they occupied very special niche of linking the energy flow among the ecosystem, which indicates they are worth researching. However, as the foundational work, it is not so clear about the taxonomy of stag beetles in the world. Especially. a lot of problematic genera and species need to be clarified, which usually caused by intraspecific traits such as sexual dimorphism and male polymorphism, or highly interspecific similarity. In this thesis, SEM was used to obtain the ultrastructure of elytra and PES of stag beetles. Our aim is to search some useful characters for identifying problematic species and revealing the relationships among higher taxa in Lucanidae based on studying four subfamilies, fifteen genera and75species (including subspecies) from China. The conclusions are presented as follows:On the level of subfamilies:1. Dorcinae shall be a valid subfamily and cannot be included in Lucaninae because of elytra setal pits with accompanying holes in Dorcinae; whereas, elytra setal pits in Lucaninae without accompanying holes, i.e., the conclusion does not support the opinion of Holloway in2007.2. The three genera, Aegus, Prismognathus and Cyclommatus cannot be taken into Dorcinae due to accompanying hole are absent on the elytra, i.e., the conclusion does not support the opinion of Bartolozzi&Sprecher in2006.3. Partly members of Prosopocoilus, such as, P. confucius, P. suturalis, P. biplagiatus, P. approximates, P. forficula forfiaila, P. blanchardi, cannot be in Dorcinae considering their accompanying holes are absent and setal pits are different.4. Odontolabinae which formed by Neolucanus and Odontolabis cannot be included in Lucaninae, too. Elytra setal pits of all the studied species from the two genera present deeply oblong pore-shape with densely granular produces and wrinkly folds which closed to the side where the elytral setae bent to. The accompanying holes are absent. These characters support that Odontolabinae actually is a valid subfamily because of these special characters. It cannot be moved into Lucaninae as Holloway had claimed in2007.On the level of genera:1. Elytra of four members of Dorcus (s.l.) share the same character, i.e., each setal pit process a distinctly distant accompanying hole. The following conclusions can be presented about them:1) The genus Macrodorcas could be invalid status because the setal pits of its generic type(M. recta) are almost same as that of Dorcus davidis which is a typical species of Dorcus (s.s). The conclusion is in accord with our known phylogeny analysis in2012.2) Hemisodorcus could be a valid genus because the setal pits of its generic type species (H. nepalensis) are deeply pore-shape, very smooth, which is distinctly different from those of Dorcus (s. s.) and Serrognathus. Nevertheless, the character is almost same as those of some species in Macrodorcas (M pieli, M. melliana, M. seguyi, M. mochizukii, M. elsiedis) and some species in Prosopocoilus(P. gracilis, P. denticulutus, P. cremilimens, P. fomosanus, P. melli). These species could be members of Hemisodorcus.3) Taxonomy of Dorcus velutinus need discussed re-newly because of two kinds of setal pit, densely needlelike tips and fan-shaped setae on the elytra surface. These characters indicated Dorcus velutinus could has new status.2. Each setal pit is immediately to each accompanying hole in Hexarthrius, Pseudorhaetus, Rhaetulus and some species of Prosopocoilus(P. spineus, P. astacoides), which can tell that they have more closer relationships.3. Taxonomy of the present Prosopocoilus shall be clarified re-newly because the above-mentioned result. All the studied species in this genus from China can be separated into three groups-based on setal pits characters.On the species level:the following characters on the elytra, flattened polygonal mounds present or absent, marked degree (easy to recognize or dim shape), setae length and shape, are useful to differ species. Also, the length, shape, distribution and adherent direction of affiliated hairs on the apical part of PES exhibited apparently differences among species. Some problematic species can be differed distinctly by analyzing the combination these elytra with PES ultrastructure:P. denticulatus is not a synonym of P. crenulidens as Benesh wrote in1960, but two valid species due to their remarkably different affiliated hairs; elytra and PES ultrastructure between yellow spot and whole dark elytra individuals of N. delicatus showed very highly similarity, which confirmed that two different splash types are actually existed; O. cuvera sinensis and O. cuvera fallaciosus could be two good species because the shapes and adherent direction between their affiliated hairs are conspicuously different. |
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