Rhynchocyon

Abstract: Three of the 4 species of giant sengis or elephant shrews (genus Rhynchocyon) have restricted geographic distributions in eastern Africa and are threatened by anthropogenic habitat loss. However, little is known about their ecology and habitat relationships. We used remotely triggered cameras to detect the gray-faced sengi (Rhynchocyon udzungwensis), which is endemic in the Udzungwa Mountains of Tanzania, with the aim of defining distributional limits, estimating occupancy patterns, and determining habitat requirements. We deployed 183 camera stations over 6 years and accumulated 4,600 camera trapping days. We refined the area of known occurrence to be 390 km 2 , thus confirming the species’ restricted range and vulnerability. We estimated the average occupancy at 56% of sites occupied on sites sampled, and found that occupancy was best predicted by the forest habitat type, with interior, closed-canopy forest supporting highest estimated sengi occupancy. Terrain slope and distance to the nearest park boundary were less important covariates, but nevertheless included among the best models. Camera-trapping rate (photographic events by day) was significantly correlated with subcanopy tree coverage. Combined, these habitat features may provide optimal conditions for antipredation vigilance (vegetation cover), and for nest-building and/or foraging on invertebrates in the thicker leaf litter on gentle slopes. Our results offer new insights into the ecology of giant sengis and confirm the potential utility of camera trapping for occupancy analysis of small, forest-dwelling mammals.

Abstract: The penis of elephant shrews is very long, extending cranially to near the sternum where it emerges from a small caudally‐pointing prepuce. The distal half of the penis lies free in a sheath and is termed the glans. In most species the corpus cavernosum is the main vascular body and extends to the tip of the penis while the corpus spongiosum around the urethra becomes much reduced distally, but in Rhynchocyon all vascular bodies are small and most of the penis consists of connective tissue. The distal tip of the penis is elaborated into various shapes, characteristic for each genus as currently defined. These penile features have more similarities with soricids and paenungulates than with archontans and lagomorphs but they are likely to be primitive characters and so should be interpreted cautiously. Copyright

Abstract: The biodiversity of northern coastal Kenya is poorly understood because security problems and poor infrastructure have discouraged access to the area. However, the wooded areas in the region have great potential for harbouring unique and rare species, including sengis or elephant-shrews (Macroscelidea). Based on recent surveys of the Boni and Dodori National Reserves, which are between the Tana River and the Somali border, the ranges of the rufous sengi (Elephantulus rufescens) and four-toed sengi (Petrodromus tetradactylus) have been extended. Although the golden-rumped sengi (Rhynchocyon chrysopygus) of coastal Kenya south of the lower Tana River was assumed to occur in the Boni forest region, this now appears to be incorrect. The Rhynchocyon east of the lower Tana River is definitely not R. chrysopygus, but rather resembles taxa found hundreds of kilometres to the south. Determining the taxonomic status of what may be a new form of Rhynchocyon will require the collection of voucher specimens and DNA tissues for detailed analyses.

Abstract: Summary The chorioallantoic placenta of the elephant shrew (Rhynchocyon) was studied at the ultrastructural level. The placenta is haemonochorial with an appparent lack of microvilli on the syncytiotrophoblastic surface. There is, however, an unusual development of subsurface bays which are covered only by an ectoplasmic layer of trophoblast. The contents of the bays is PAS-negative and is similar in both texture and appearance to the maternal blood plasma. The basal trophoblastic cells are exceptionally tall and are held together by numerous desmosomes. Their basal lamina, which is on the trophospongial side, it unusually thick. At the fetomaternal junction the basal trophoblastic cells are coated with a finely granular electron-dense precipitate of unknown nature. Electron-dense particles resembling iron deposits are demonstrable in the fetal mesenchyme of the labyrinthine zone.