Antechinus

Antechinus
Antechinus flavipes, from Brehms Tierleben
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Dasyuromorphia
Family: Dasyuridae
Subfamily: Dasyurinae
Tribe: Phascogalini
Genus: Antechinus
Macleay, 1841
Type species
Antechinus stuartii
Macleay, 1841
Species

Antechinus /æntɪˈkaɪnəs/ ('ant-echinus') is a genus of small dasyurid marsupial indigenous to mainland Australia, Tasmania and New Guinea. They resemble mice with the bristly fur of shrews. The majority of Antechinus species occur in Australia and only two species have been described in New Guinea. They are sometimes also called broad-footed marsupial mice, pouched mice, route rat and/or antechinus shrews. However, these common names are considered either regional or archaic and the modern common name for the animals is antechinus.

Antechinuses are small, carnivorous, shrew-like animals that primarily prey on invertebrates such as spiders, beetles (including larvae), and weevils. Some are strictly terrestrial and hunt only at ground level, while others are arboreal (tree-climbing) in nature. Most species nest communally in tree-hollows. Their primary habitats are: swamps, tropical rainforests, temperate rainforests and woodlands.

Antechinuses have short hair and vary from grey-cinnamon-brown-black in colour depending on the species. They have prominent whiskers, large ears and a pronounced, pointed snout, giving them an overall shrew-like appearance. Species vary from 80–120 mm, nose-to-tail (80 mm = female A. agilis, 120 mm = male A. swainsonii) and weight 16–170 g (16 g = female A. agilis, 170 g = male A. swainsonii) when fully grown.

Sexual dimorphism occurs in most species for both weight and skeletal measurements, with males being typically larger and heavier. A. agilis is the smallest known species, and A. swainsonii the largest. Species in Papua New Guinea are not well documented and unknown Papuan species and subspecies likely await discovery.

Reproduction

All Antechinus species except for A. swainsonii are semelparous at least as males – and usually as females, too – meaning that an individual usually only lives long enough to breed once in its lifetime. Breeding occurs in winter (usually August–September) at a time when little food is available in the environment.

To accomplish this, a male strips its body of vital proteins and also suppresses the immune system so as to free up additional metabolic energy. In this way, an individual male trades away long-term survival in return for short-term breeding success, and following the breeding season, a complete die-off of physiologically exhausted males occurs. Breeding is intensely competitive. Males produce large amounts of testosterone and mate-guarding occurs in the form of protracted copulation (up to twelve hours in some species).[1]

The females can store sperm for up to three days in specialized sperm-storage crypts in the ovary and do not ovulate until the end of the breeding season. Many litters have multiple paternity (i.e. several fathers contribute to a single litter). Females can live for 2–3 years. However, this is unusual, and most females die following the weaning of their first litter. Litter size depends on the number of teats in the pouch.

As few as four teats, usually eight, and in some populations up to ten, can occur. The cause of this variation in number is unknown, but in food-poor environments, selection likely has tended towards fewer teats, so that greater parental investment occurs per offspring.

Antechinus babies can weigh as little as 4 grams and are some of the smallest Australian marsupial babies.

Species

Brown antechinus, here a minor indoor pest

References

  1. ↑ Fisher, Diana O.; Dickman, Christopher R.; Jones, Menna E.; Blomberg, Simon P. (2013-10-29). "Sperm competition drives the evolution of suicidal reproduction in mammals". Proceedings of the National Academy of Sciences. 110 (44): 17910–17914. doi:10.1073/pnas.1310691110. ISSN 0027-8424. PMC 3816400. PMID 24101455.
  2. ↑ Andrew M Baker, Thomas Y Mutton & Harry B Hines (2013). "A new dasyurid marsupial from Kroombit Tops, south-east Queensland, Australia: the silver-headed antechinus, Antechinus argentus sp. nov. (Marsupialia: Dasyuridae)". Zootaxa. 3746 (2): 201–239. doi:10.11646/zootaxa.3746.2.1.
  3. ↑ Baker; Mutton; Mason; Gray (2015). "A taxonomic assessment of the Australian Dusky Antechinus Complex: a new species, the Tasman Peninsula Dusky Antechinus (Antechinus vandycki sp. nov.) and an elevation to species of the Mainland Dusky Antechinus (Antechinus swainsonii mimetes (Thomas))". Memoirs of the Queensland Museum. 59. doi:10.17082/j.2204-1478.59.2015.2014-10.
  4. ↑ Baker, A.M.; Mutton, T.Y.; Dyck, S. van 2012: A new dasyurid marsupial from eastern Queensland, Australia: the buff-footed Antechinus, Antechinus mysticus sp. nov. (Marsupialia: Dasyuridae). Zootaxa, (3515): 1-37. Preview
  5. ↑ Baker; Mutton; Mason; Gray (2015). "A taxonomic assessment of the Australian Dusky Antechinus Complex: a new species, the Tasman Peninsula Dusky Antechinus (Antechinus vandycki sp. nov.) and an elevation to species of the Mainland Dusky Antechinus (Antechinus swainsonii mimetes (Thomas))". Memoirs of the Queensland Museum. 59. doi:10.17082/j.2204-1478.59.2015.2014-10.
  • Black-tailed Antechinus discovery
  • Groves, C.P. (2005). Wilson, D.E.; Reeder, D.M., eds. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 28–30. ISBN 0-801-88221-4. OCLC 62265494.
  • "Antechinus". Integrated Taxonomic Information System. Retrieved 2 February 2006.
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