Language: English
All organ systems of mesothelid spiders are revised and supplemented with new information. This concerns particularly the eyes, which were studied by TKM comparing the data with previous results. Based on ultrastructure, histology and experimental observations a hypothesis on vision in heptathelid spiders is proposed. The ultrastructure of the mesothelid tarsal organ and the trichobothria is described for the first time. Both organs are equipped with numerous sensory cells. The respiratory capabilitiy of mesothelids is investigated and discussed in relation to mygalomorph and araneomorph spiders, which represent the two major taxa of opisthothelid Araneae.
A special chapter is devoted to the morphology and function of the male palpal organ which is compared to respective organs in mygalomorph and araneomorph spiders. Its function is explained using morphological and experimental data. Ecological aspects deal with the habitats of Mesothelae and especially microbial diseases. In the chapter on taxonomy current problems concerning mesothelid species are critically discussed from a general zoological perspective.
1. Introduction 1
2. History of discovery 2
3. Material and methods 3
4. Morphology of Mesothelae, form and function 4
4.1 Epidermis, cuticle and epidermal glands 4
4.2a The body and its appendages 7
4.2b Skeleton and muscles 9
4.3 Nervous system 11
4.3a Neurosecretory organs 11
4.3b Sense organs 13
4.3b.1 Eyes 13
4.3b.2 Mechanoreceptive sense organs 17
Setae and `spines' 17
Trichobothria 18
Slit and lyriform organs 22
Proprioreceptors 24
4.3b.3 Chemical sense 24
Setae 24
Tarsal organ 24
4.4 Intestinal system 24
4.5 Haemolymph system 27
4.5a Vessels. 27
4.5b Haemolymph and haemocytes 27
4.6 Respiratory system 30
4.6a Booklungs and tracheae 30
4.6b Respiratory physiology 30
4.7 Excretory system 32
4.8 Reproductive system 33
4.8a Female gonads 33
4.8b Male gonads 33
4.8c Sperm cells 35
4.8d Male secondary sexual organ 37
4.9 Spinning apparatus 40
4.9a Spinnerets and spigots. 40
4.9b Anatomy and histochemistry of silkglands 43
4.9c Use of silk 44
4.9d Phylogenetic aspects of the silkgland system 44
5. Cytogenetics and molecular biology 46
6. Life cycle 47
6.1 Deposition of eggs and the embryonal development 47
6.2 Postembryonal development 49
6.3 Moulting process 49
6.4 Longevity, aging and death 51
7. Behaviour 54
7.1 Circadian and annual rhythms 54
7.2 Construction of the burrow 54
7.3 Capture of prey 55
7.4 Aggressive behaviour 56
7.5 Mating process 56
7.6 Sexual communication by means of pheromones and bioacoustics 59
7.7 Phylogenetic aspects of mating behaviour 60
8. Ecology 62
8.1 Biotopes of Mesothelae 62
8.2 Burrows and burrowing sites and their microclimatic aspects 62
8.3 Enemies and parasites 65
8.4 Fungal and microbial diseases 65
9. Taxonomy 67
9.1 Systematics of Mesothelae. 67
9.2 The species problem in Mesothelae 80
10. Geographic distribution and biogeography 83
11. Phylogenetic discussion 89
11.1 "Mesothelae" and Mesothelae the evaluation of fossil spiders 89
11.2 Phylogenetic analysis of Recent Mesothelae 89
12. Acknowledgements 94
13. Summary 94
14. Zusammenfassung 95
15. References 96