ABSTRACT
The basic biology of onychophorans was revealed slowly and controversially during much of the 19th century. Communications were in Latin, French, Spanish, German and English. This information was synthesised in the monumental monographs of Bouvier in 1905 and 1907. However, amongst this multicultural endeavour is a significant Russian contribution by Nikolai Sänger, a student of Professor Leuckart of the Zoological Institute in Leipzig, Germany. Sänger requested a specimen of Onychophora from the Institute’s collection for serial sectioning. This resulted in a detailed account of the anatomy of Peripatopsis capensis. Sänger’s description of the extensive slime glands was the first to recognise them as the hallmark of onychophorans for defence and prey capture, and not the male reproductive system as previously claimed. Based on these morphological observations, he correctly concluded that onychophorans are not hermaphrodites and, furthermore, are “predominantly predaceous” animals. He further appropriately assigned the slime glands and salivary glands to the slime papilla segment, despite the lack of embryological data at that time. Sänger also identified the excretory organs (nephridia) and their openings, although he erroneously assigned them to a dual role of excretion and respiration. Moreover, he highlighted the importance of the position of the genital opening as a diagnostic character, described the ventral/preventral organs as “subcutaneous glandules”, identified the neurilemma enclosing the central nervous system, and recognised “oval holes of different sizes” in each nerve cord that were subsequently demonstrated to represent giant fibres. Of interest to parasitologists, he discovered a larval acanthocephalan encysted within the cutaneous muscles of his specimen of P. capensis, suggesting that onychophorans act as a secondary host for this parasite. Sänger’s memoir concludes with a brief but important description of the first species of Onychophora recorded from Australia, “northwest of Sydney, New Holland”. This species is now known as Euperipatoides leuckartii with a neotype designated from a specific location northwest of Sydney.
Cognition and the evolution of camouflage
