Hairy-nosed Wombat Lasiorhinus Latifrons Research Articles

Ovary of the southern hairy-nosed wombat (Lasiorhinus latifrons): its divergent structural organisation.

The organisation of the ovarian interstitial tissue in the southern hairy-nosed wombat Lasiorhinus latifrons was investigated. Unlike in most other marsupials, the outer cortical region of the ovary contains abundant luteinised interstitial tissue that largely occurs in discrete lobules, many of which contain a localised area of non-cellular, highly eosinophilic and periodic acid-Schiff-positive material. The findings suggest that the latter arises from the zona pellucida that surrounded the oocyte in growing follicles and that the luteinised interstitial tissue thus developed from transformed theca interna of degenerated atretic follicles. It is hypothesised that this tissue synthesises and secretes progestogens, which may result in the long, and variable, oestrous cycle length that has been found to occur in this species.

Effect of exogenous gonadotrophins on ovarian morphology and oocyte maturation in the southern hairy nosed wombat Lasiohinus latifrons during the breeding season

The effect of the exogenous administration of porcine follicle-stimulating hormone (pFSH) and pregnant mare serum gonadotrophin (PMSG) on ovarian follicular development and oocyte maturation in the southern hairy nosed wombat Lasiorhinus latifrons was investigated. Three experimental groups were administered pFSH at various doses and for different treatment lengths, followed by 25 mg porcine luteinising hormone (pLH) 12 h after the last dose of pFSH. Another group was given PMSG followed 72 h later by 25 mg pLH. Animals were killed 24 h after pLH. The left ovary was fixed for histology and the morphology of the antral follicles was determined, whereas follicular oocytes in the right ovary were aspirated, fixed, stained with 42,62-diamidino-2-phenylindole, and viewed for nuclear maturation. There was no significant difference in the mean number of ovarian follicles >1 mm, or in the size class of follicles assessed between control and experimental groups. However, a trend was observed suggesting a possible increase in follicles >3.0 mm in experimental groups compared with control animals. In all females administered exogenous porcine gonadotrophins, but not controls, some of the mural granulosa cells of large tertiary antral follicles had markedly enlarged nuclei (approximately 14 microm in diameter). All oocytes from the control group remained at the germinal vesicle stage, whereas approximately 40% of oocytes retrieved from the pFSH groups and 82.4% retrieved from the PMSG-primed animals had undergone germinal vesicle break down, with a small number reaching meiosis II. The present study shows that exogenous administration of either pFSH or PMSG to hairy nosed wombats can induce follicular growth and oocyte maturation. Such findings could be useful in the development of reproductive technology in this species.

Seasonal changes in the testis, accessory glands and ejaculate characteristics of the southern hairy‐nosed wombat, Lasiorhinus latifrons (Marsupialia: Vombatidae)

AbstractMost mammals exhibit seasonal variation in the reproductive capacity of one or both sexes. While the female southern hairy‐nosed wombat Lasiorhinus latifrons is a known seasonal breeder, the extent of seasonality in the male has not been documented. To examine this, gross body measurements including scrotal diameter and the dimensions of the accessory gland bulge were recorded and male reproductive tracts were examined between 1993 and 2000. Testes, epididymides and accessory glands from all males were dissected free of connective tissue and weighed. In addition, matched semen samples were collected over four time points in 2000 corresponding to the breeding season (September), immediately post‐breeding season (November), during the non‐breeding season (January), and immediately before the onset of the next breeding season (June) as determined from female reproductive status. Semen was collected by electro‐ejaculation and analysed for volume, sperm number and motility characteristics. Ejaculate volume, total ejaculate sperm number, percentage motile sperm, and the sperm motility rating and index were all significantly elevated in September and significantly lower in November and January. This correlated with a significant increase in body weight, peri‐cloacal gland width, and the weights of the prostate, Cowper's glands, urethral bulb and crus penis. The data confirm that male reproduction in the southern hairy‐nosed wombat, like that of the female, is highly seasonal with a peak in reproductive capacity occurring in August–September and a reduction by November.

Burrow use and ranging behaviour of the southern hairy‐nosed wombat ( Lasiorhinus latifrons ) in the Murraylands, South Australia

This study investigated burrow use and ranging behaviour in the southern hairy-nosed wombat Lasiorhinus latifrons in semi-arid South Australia. Sixteen adult wombats were fitted with radio transmitters and monitored monthly from July 2001 to February 2002. Wombats generally used between one and five warrens, preferred large warrens with a greater number of entrances and showed a preference for one or two warrens. Across the study period there was no apparent change in burrows used within warrens. Radio-tracking indicated that animals spent very little time above ground (26% of 1115 night-time fixes), centred their activity around their preferred warrens, and moved, on average, 99 m/h and 221 m/night. Mean home-range size, estimated using minimum convex polygons and the harmonic mean method from location data, obtained through triangulation, and daytime warren fixes, ranged from 1.3 to 4.8 ha. Home-range size was similar between males and females and home ranges overlapped substantially. The data highlight the importance of burrows to southern hairy-nosed wombats in shaping their home ranges. It seems likely that the use of burrows and a specialized diet are important energy saving strategies for this species in such unpredictable regions of South Australia.

Sarcoptes scabiei: an important exotic pathogen of wombats

Sarcoptes scabiei is a parasitic astigmatid mite, which causes scabies in people and sarcoptic mange in mammals. Importantly, it is an emerging disease in wildlife throughout the world. The mite originates from a human ancestor and is thought to have spread to domestic and then free-living animals. Based on the recent emergence of sarcoptic mange in Australian wildlife and Aboriginal communities, it is thought that Sarcoptes scabiei was probably introduced to Australia by the Europeans and their animals. The mitochondrial genetic similarity of mites from Australian wildlife and domestic animals supports this. In Australian wildlife, sarcoptic mange has been reported in the common wombat Vombatus ursinus, southern hairy-nosed wombat Lasiorhinus latifrons, koala Phascolarctos cinereus, common ringtail possum Pseudocheirus peregrinus and in 2003 in the agile wallaby Macropus agilis. Compared with other native species, sarcoptic mange has by far its greatest impact on wombats, particularly common wombats, and is capable of causing high morbidity and mortality rates.

Osteological Differences of the Skulls of Lasiorhinus-Latifrons Owen, 1845 and Vombatus-Ursinus Shaw, 1800 (Marsupialia, Vombatidae)

The two extant genera of wombats, the hairy-nosed wombat Lasiorhinus latifrons and common wombat Vombatus ursinus, are distinguishable by their skull morphology. Significant size differences were found for skull length, nasal length binasal breadth, bitemporal breadth, bizygomatic breadth, parietal bone thickness and mandible length. The important different gross morphological features are summarised to allow rapid identification of these two species. A number of new diagnostic differences are described which distinguish the species from dorsal, lateral and ventral views and on the basis of mandibles and dentition. Some of these differences, and those listed in the results, also distinguish the Pleistocene fossil wombats V. mitchelli (Owen, 1838) and L. krefftii (Owen, 1871) from each other, and strongly suggest their generic status.