A Marine Euplotes (Ciliophora, Hypotrichida) with Reduced Number of Prezygotic Micronuclear Divisions

In contradistinction to the pattern of 3 prezygotic micronuclear divisions found in 10 species of Euplotes, a marine species resembling Euplotes crassus in structure, has only 2 divisions. This atypical division pattern was observed in all matings involving the 4 available mating types. The critical stages of the nuclear events are demonstrated by using special strains having the micronuclear DNA content and chromosome number only 1/2 the normal values. The employment of such strains facilitates differentiation between the stationary and migratory pronuclei in a given conjugant and determination of the times of conclusion of prezygotic divisions and of the pronuclear exchange.     

Some Notes on the Morphology of an Aberrant Actinian (Hexacorallia, Actiniaria) Associated with the Glaucothoe of the Hermit Crab Paguropsis typica Henderson (Anomura, Paguridae)

The planktonic glaucothoe of the Indo-West Pacific hermit crab Paguropsis typica Henderson has an aberrant anthozoan polyp, identified as a nynanthean actinian, attached to the underside of its thorax. The morphology of the anemone is described. The scapus is dumb-bell shaped and exhibits a slit-like mouth opening oriented transverse to the animal's siphonoglyphal plane. The gonads are very well developed, whereas tentacle-like structures or retractor muscles of certain septa are reduced. In the adult stage, Paguropsis typica is associated with the zoanthidean Epizoanthus paguropsides . It is assumed that the actinian is lost at the ecdysis leading to the first hermit stage and that P. typica might possibly seize a free Epizoanthus colony and adapt it to its body.     

H-Y Antigen and Sex-Determination in Turtles

H-Y antigen was investigated in 14 turtle species belonging to five different families. In 13 species the female was typed as H-Y antigen positive, only in Chinemys reevesi was the male H-Y antigen positive. Since in all vertebrate species studied till now, the expression of H-Y antigen is strictly correlated with the heterogametic sex, it can be assumed that in turtles both types of sex determining mechanisms are realized, namely the ZZ/ZW-and the XX/XY mechanism; both mechanisms are realized in species belonging to one and the same turtle family. However, most turtle species seem to be endowed with a ZZ/ZW sex determining mechanism.     

Diarthrodella chilensis sp.n. und Rossopsyllus kerguelenensis quellonensis subsp.n. (Copepoda, Paramesochridae) von Chile

During a collecting trip to Chile, two species of Paramesochridae belonging to the genera Diarthrodella and Rossopsyllus were found. The new species D. chilensis is widely distributed on the coasts of central Chile. Up to now, the new subspecies R. kerguelenensis quellonensis is only known from Quellón, Island of Chiloé. The nominate subspecies R. kerguelenensis kerguelenensis Soyer, 1974 was described from the Kerguelen Archipelago.     

Ostracode fauna, stratigraphy and definition of the Beyrichienkalk sequence

An essential clue to the uppermost Silurian in the submarine Baltic arca is the Beyrichienkalk. According to recent investigations it constitutes a glacial drift boulder sequence characterized by four ostracode associations with about sixty species. In the correlation of ostracode zones of Baltoscandia these associations form a connecting link and thus are also of biozonal character. In the terms of regional stratigraphic units (East Baltic arca). the lower stratigraphic boundary of this sequence lies approximately at the beginning of the Kuressaare beds and the top in the upper Ohesaare beds. The term Beyrichienkalk should be used for those glacial erratics that are characterized by typical ostracodes of the four associations defined here.     

Localization of unmyelinated axons in rat skin and mucocutaneous tissue utilizing the isolectin GS-I-B

The a-D-galactose specific isolectin I-B4 from Griffonia simplicifolia (GS-I-B4) labels CNS microglia and certain peripheral neurons, including a subpopulation of small dark, type B dorsal root ganglion cells, some post-ganglionic sympathetic axons, and nearly all peripheral gustatory axons. The innervation patterns of GS-I-B4 reactive sensory ganglion cells are unknown for many peripheral target tissues, including their probable primary target, the skin. The present study describes the distribution of GS-I-B4 reactive axons in hairy and glabrous hindpaw skin and in the glans penis of rats, using both single and double-labelling histochemical techniques. Neuronal processes were identified using (1) histochemistry with horseradish peroxidase conjugated GS-I-B4 or (2) immunohistochemistry against PGP 9.5 to identify all axons, and biotinylated lectin histochemistry with avidin-FITC to identify the subpopulation of GS-I-B4 reactive axons. GS-I-B4 strongly labelled unmyelinated cutaneous sensory afferents, as well as some sympathetic efferents and visceral afferents. Lectin reactive axons were seen to innervate the upper hair shaft epidermis in hairy skin, and were abundant in the shallow dermis in hairy and glabrous skin and glans penis. Lectin reactive axons were also abundant in the lamina propria and distal urethral epithelium of the penis. These results provide new evidence for the cutaneous sensory role of GS-I-B4 reactive primary afferents, as well as evidence to support the contention that the lectin is a specific marker for a subpopulation of unmyelinated axons and not simply a marker for the myelination state of an axon.     

A new genus of African Karniellina (Orthoptera,Tettigoniidae, Conocephalinae,Conocephalini): integrating morphological,molecular and bioacoustical data

Melanoscirtes gen.n. is established within Karniellina. The members of this subtribe are small conocephaline bush crickets, confined to Africa. Melanoscirtes is erected on Phlesirtes kibonotensis, a species restricted to forest clearings and forest edge in the submontane and montane zones of Mt. Kilimanjaro. A subspecies, M. kibonotensis uguenoensis, is described from the North Pare mountains, a mountain range of the Eastern Arc adjacent to Mt. Kilimanjaro. Further species of Melanoscirtes occur on other mountain ranges of the northern branch of the Eastern Arc mountains of northern Tanzania and southern Kenya. The South Pare mountains harbour M. shengenae; the West Usambaras, M. usambarensis, and the Taita Hills, M. taitensis. All species and subspecies of Melanoscirtes exhibit a similar morphology and occupy analogous habitats on the respective mountains. The song patterns for all species found within this genus are very similar, and this, together with evidence from molecular data, suggests that allopatric speciation is the reason for the biogeographic pattern found in this genus. A key for the subspecies and species of Melanoscirtes is provided.