Hilke Ruhberg

A hemocyanin from the Onychophora and the emergence of respiratory proteins.

The velvet worms (Onychophora) are considered living fossils and are closely related to the Euarthropoda. Onychophora possess a tracheal system for respiratory function, but oxygen-transport proteins have been considered unnecessary. Here, we show that the hemolymph of the Epiperipatus sp. (Onychophora: Peripatidae) contains an arthropod-type hemocyanin, demonstrating that such protein exists outside the Euarthropoda. Thus, the evolution of oxygen carriers preceded the divergence of the Onychophora and Euarthropoda and was most likely linked to the evolution of an efficient circulatory system in a low-oxygen environment. The cDNA of the Epiperipatus hemocyanin subunit comprises 2,287 bp and encodes for a protein of 641 aa (73.6 kDa). Phylogenetic analyses of the arthropod hemocyanin sequences show that the Onychophora form a robust sister-group of the Euarthropoda, whereas the monophyly of the Tracheata is not supported.

Ultrastructure of the Body Cavity Lining in Embryos of Epiperipatus biolleyi (Onychophora, Peripatidae): A Comparison with Annelid Larvae

In contrast to the Annelida, no trace of the developing coelomic cavities persists in the body cavity of postembryonal stages of Onychophora and Euarthropoda; instead, a primary body cavity or haemocoel is characteristic for these stages. Transitory coelomic cavities, which appear in certain developmental stages of arthropods, are generally regarded as recapitulation of paired and segmental coelomic cavities of the common ancestor of annelids and arthropods. If this is true, a specific organization of these cavities with respect to the annelid coelom is to be expected. In order to test this assumption, the transitory coelomic cavities of the onychophoran Epiperipatus biolleyi are investigated ultrastructurally and compared with data on the coelomogenesis of the polychaetous annelids Ophelia rathkei, Spirorbis spirorbis, and Pectinaria koreni. The somatic wall of the transitory coelom of Epiperipatus biolleyi is thicker than the visceral (splanchnic) wall; the lining cells are apically connected by adhaerens junctions and possess a rudimentary cilium, and are otherwise largely undifferentiated. The latter observation is clearly in contrast to comparably differentiated coelomic cavities in annelids. During further development the haemocoel is formed in Epiperipatus biolleyi. A survey of the older literature reveals that in the Onychophora the haemocoel is formed by fusing interstices within the subepidermal and peri-intestinal matrix, and not by a fusion of such interstices and the

Fine structure of the sensilla of Peripatopsis moseleyi (Onychophora)

SummaryThree types of sensilla occurring on the lips and on the antennae of Peripatopsis moseleyi have been investigated by scanning and transmission electron microscopy. On the lips sensory spines can be found which contain numerous cilia originating from bipolar receptor cells. They reach the tip of the spine where the cuticle is modified. The perikarya of the sensory cells, a large supporting cell with a complicated surface and a second type of receptor, form a bud-like structure and are surrounded by a layer of collagen fibrils. The second receptor cell bears apical stereocilia as well as a kinocilium which are directed towards the centre of the animal — thus the cell appears to be turned upside down. The sensilla of the antennae are 1) sensory bristles containing two or three kinds of receptor cells, one of which bears an apical cilium and one kind of supportive cell and 2) sensory bulbs located within furrows consisting of receptor cells with branched cilia and two kinds of supportive cells which are covered by a modified thin cuticle. According to the electron microscopical findings the sensory spines on the lips are presumably chemoreceptors. The sensory bristles on the antennae can be regarded as mechanoreceptors and the sensory bulbs as chemoreceptors.

Morphological assessment supports the recognition of four novel species in the widely distributed velvet worm Peripatopsis moseleyi sensu lato (Onychophora : Peripatopsidae)

Abstract. A recent phylogenetic study based on DNA sequence data (COI + 18S rDNA) together with basic morphological characteristics demonstrated the presence of four novel lineages within the widely distributed South African velvet worm species Peripatopsis moseleyi sensu lato (Onychophora, Peripatopsidae). In the present study, the morphological variation within P. moseleyi (Wood-Mason, 1879) is quantified and the novel species delineated and described. A total of 31 new specimens were collected from the Amathole Mountains in the Eastern Cape while a further 12 specimens were collected from Mount Currie Nature Reserve, KwaZulu-Natal, South Africa. These samples together with selected specimens from the DNA study material were subjected to scanning electron microscopy (SEM) to investigate the presence of diagnostic morphological characters that could potentially be utilised in the delineation of the four novel lineages. The species diagnosis of P. moseleyi (Wood-Mason, 1879) is elucidated and amended since the original type description is inadequate and could apply to several Peripatopsis taxa. A neotype for P. moseleyi is designated because the syntypes appear lost. Four new species of Peripatopsis Pocock, 1894 are described; viz. Peripatopsis birgeri, sp. nov., P. hamerae, sp. nov., P. janni, sp. nov. and P. storchi, sp. nov.

Zur Entstehung der Spermatophore vonOpisthopatus cinctipes Purcell, 1899 (Onychophora, Peripatopsidae)

SummaryAll parts of the male genital tract ofOpisthopatus cinctipes are involved with the formation of the Spermatophore.In the spermatocytes within the testes a Golgi apparatus produces electron dense secretory granules merging into one large droplet, which is extruded by the spermatid within the seminal vesicle.A second vesicular structure is formed near the plasmamembrane of the spermatids by a Golgi apparatus. It is presumably an acrosome vesicle and is extruded into the seminal vesicle, too.During the passage through the vasa efferentia secretory products and sperm-cells are separated from each other, the secretory products building an envelope around the spermatozoa.The epithelium of the vas deferens adds a multilayered outer covering. Some parts of the male genital tract bear cilia (vasa efferentia, vas deferens).ZusammenfassungAlle Teile des männlichen Genitaltraktes vonOpisthopatus cinctipes sind an der Entstehung der Spermatophore beteiligt.In den Spermatocyten der Hoden werden in großer Zahl elektronendichte Sekreteinschlüsse produziert, die in den Vesiculae seminales zusammenfließen und aus der Spermatide in das Vesicula-Lumen entlassen werden.Während der Spermiocytogenese wird ein zweiter Typ von Einschlußkörpern gebildet, den wir als Akrosom-Vesikel deuten; auch er wird in der Samenblase ausgeschleust.In der Passage durch die Vasa efferentia werden fast reife Spermien und Sekret voneinander getrennt. An der Peripherie liegen die Sekrete, im Zentrum die Spermien.Im Vas deferens werden die Samenpakete von einer mehrschichtigen Sekrethülle umgeben. Durch den muskulösen Ductus ejaculatorius wird die Spermatophore abgegeben, auch in ihm finden sich Drüsenzellen.Dem Transport dienen in Vasa efferentia und Vas deferens Cilien.

Zur Ultrastruktur von mÄnnlichem Genitaltrakt, Spermiocytogenese und Spermien vonPeripatopsis moseleyi (Onychophora)

SummaryThe ultrastructure of the male genital tract ofPeripatopsis moseleyi has been examined under the electron microscope. In the testes somatic cells, spermatogonia and spermatocytes occur. In the spermatocytes electron-dense granules are built by the Golgi-apparatus. They are released from the developing spermatid and can still be detected in the spermatophore. The spermiogenesis takes place in the seminal vesicles. Nuclear condensation and elongation, formation of middle piece and acrosome are described. The mature sperm cell has an elongated nucleus, a middle piece containing mitochondria only and a tail with 9+2-formation and accessory microtubule systems. The spermatophore is built within the vas deferens the epithelial cells of which secrete great amounts of material enveloping the sperm mass.ZusammenfassungDie Ultrastruktur des Genitaltraktes vonPeripatopsis moseleyi wird beschrieben.Im Hoden finden sich neben somalischen Zellen Spermatogonien und Spermatocyten. In letzteren werden in gro\er Zahl Sekreteinschlüsse gebildet, die spÄter zusammenflie\en und abgegeben werden; sie sind noch in der Spermatophore nachweisbar. Die Spermiocytogenese lÄuft in den Vesiculae seminales ab. Kernkondensation und -Umformung, Mittelstückformation und Akrosombildung werden beschrieben. Das reife Spermium hat einen langgestreckten Kern, ein Mittelstück, das nur aus Mitochondrien besteht, und einen Schwanz mit verschiedenen Mikrotubulus-Formationen. Die Spermatophorenbildung geht mit intensiver Sekretion der Epithelzellen des Vas deferens einher.

Electron microscopic observations on the male genital tract and sperm development in Peripatus sedgwicki (Peripatidae, Onychophora)

Summary The male genital tract of Peripatus sedgwicki is composed of paired structures (testes, vesiculae seminales, vasa efferentia) and the unpaired vas deferens and ductus ejaculatorius. The vas deferens may attain the total body length in mature males. The testes contain supportive cells, spermatogonia, and spermatocytes. All stages of spermiogenesis were found in the vesiculae seminales. They are characterized by secretions, which are a special feature of Onychophora. Vasa efferentia and vas deferens are lined by various epithelial cells, among which secretory cells are dominant. The ductus ejaculatorius is lined by a cuticle. Spermiogenesis in P. sedgwicki is similar to that of Peripatopsidae. However, sperm cells of Peripatidae and Peripatopsidae differ considerably.

Revision of Tasmanian viviparous velvet worms (Onychophora : Peripatopsidae) with descriptions of two new species

Abstract. The restricted distribution of viviparous onychophorans in Tasmania has long been a subject of discussion, but their evolutionary history remains unclear. We applied morphological, molecular and karyological methods to assess the taxonomy and phylogenetic relationships of the four viviparous species reported from Tasmania, including Tasmanipatus barretti, T. anophthalmus and two undescribed species previously referred to as ‘Tasmania’ sp. 1 and sp. 2. We demonstrate that all four species can be unambiguously distinguished based on independent character sets. The two ‘Tasmania’ species, which were previously thought to be cryptic, proved to exhibit a set of distinct morphological characters. Molecular phylogenetic analyses revealed that the four species belong to a major clade that includes Peripatoides from New Zealand, and that species from the two landmasses show reciprocal monophyly within this clade. Within the Tasmanian clade, T. anophthalmus is more closely related to the two ‘Tasmania’ species than to T. barretti. Based on this relationship and the lack of morphological and/or karyological characters supporting the Tasmanian viviparous clade, we erect two new genera to accommodate the two ‘Tasmania’ species (Diemenipatus, gen. nov.) and T. anophthalmus (Leucopatus, gen. nov.). An emended diagnosis followed by a redescription of T. barretti is provided and ‘Tasmania’ sp. 1 and sp. 2 are formally described as D. taiti, gen. et sp. nov. and D. mesibovi, gen. et sp. nov., respectively.