Epidemiology and genetic characteristics of murine kobuvirus from faecal samples of Rattus losea, Rattus tanezumi and Rattus norvegicus in southern China

Recently, murine kobuvirus (MuKV), a novel member of the family Picornaviridae, was identified in faecal samples of Rattus norvegicus in China. The limited information on the circulation of MuKV in other murine rodent species prompted us to investigate its prevalence and conduct a genetic characterization of MuKV in Rattus losea, Rattus tanezumi and Rattus norvegicus in China. Between 2015 and 2017, 243 faecal samples of these three murine rodent species from three regions in southern China were screened for the presence of MuKV. The overall prevalence was 23.0% (56/243). Three complete MuKV polyprotein sequences were acquired, and the genome organization was determined. Phylogenetic analyses suggested that our sequences were closely related to Chinese strains and belong to the species Aichivirus A in the genus Kobuvirus. Additional studies are required to understand the true prevalence of MuKV in murine rodent populations in China.

Nematoda Parasit Pada Bunomys spp. di Pegunungan Mekongga, Sulawesi Tenggara

Study on the nematode parasite species of Bunomys spp. from Mekongga Mountain, Southeast Sulawesi was conducted on deposited specimens in Museum Zoologicum Bogoriense, Zoology Division, Research Center of Biology-LIPI. Bunomys is endemic genus murine rodent in Sulawesi. This study aims to determine the types of nematodes in endemic Muridae rodent, the results of which can help the government in developing disease management plans. The nematodes identified in this study were Subulura andersoni (host: B. andrewsi), Syphacia rifaii (host: B. chrysocomus), Cyclodostomum purvisi (host: B. penitus), Heterakis spumosa (host: B. chrysocomus). Except for Sy. muris, all of the recorded nematodes have worldwide distribution. Morphology and taxonomy of nematodes will be discussed in this paper

Anatomy of the brachial plexus in the Mongolian gerbil (Meriones unguiculatus Milne-Edwards, 1867)

The Mongolian squirrel is a murine rodent widely used as an experimental model and kept as a pet. With respect to the significance of the brachial plexus, we aimed to describe the origin and the nerves that constitute it, providing new information about the neuroanatomy of this species. Twenty adult animals were used, which were fixed in a 10% formaldehyde solution at the Applied Animal Morphophysiology Laboratory of the Brazilian Federal University of the Semi-Arid Region (UFERSA). The animals were medially incised with an opening of the thoracic cavity, and then bilateral dissection was carried out. Once the nerves were identified, cotton wool soaked with a 2% hydrogen peroxide solution was added for bleaching and better visualisation of structures. The gerbil brachial plexus derived from ventral roots of the fourth, fifth, sixth, seventh and eighth cervical nerves (C₄–C₈) and the first thoracic root (T₁). The suprascapular nerve was formed from the nerve roots C₄ and C₅; the subscapular and cranial pectoral nerves from C₅ and C₆; the musculocutaneous and axillary nerves from C₅, C₆ and C₇; and the caudal pectoral, radial, median, ulnar, thoracodorsal, lateral thoracic and long thoracic nerves from C₇, C₈ and T₁. This resembles what is described in other rodents, such as the rat and capybara. The gerbil has a pre-fixed plexus conformation.

Sperm morphology of the Rattini – are the interspecific differences due to variation in intensity of intermale sperm competition?

It is widely accepted that in mammals a causal relationship exists between postcopulatory sexual selection and relative testes mass of the species concerned, but how much it determines sperm size and shape is debatable. Here we detailed for the largest murine rodent tribe, the Rattini, the interspecific differences in relative testes mass and sperm form. We found that residual testes mass correlates with sperm head apical hook length as well as its angle, together with tail length, and that within several lineages a few species have evolved highly divergent sperm morphology with a reduced or absent apical hook and shorter tail. Although most species have a relative testes mass of 1–4%, these derived sperm traits invariably co-occur in species with much smaller relative testes mass. We therefore suggest that high levels of intermale sperm competition maintain a sperm head with a long apical hook and long tail, whereas low levels of intermale sperm competition generally result in divergent sperm heads with a short or non-existent apical hook and shorter tail. We thus conclude that sexual selection is a major selective force in driving sperm head form and tail length in this large tribe of murine rodents.