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Mystacina robustaNew Zealand greater short-tailed bat

By Brendan Boyes

Geographic Range

Until 1965, Mystacina robusta was only known to have existed on Big South Cape and Solomon Islands in New Zealand. Subfossils in swamps and caves in the North and South Islands suggest its range was much larger several hundred years ago (King, 1990). Several hundred bats of this species occupied a cave at Puwai on Big South Cape Island until 1964-65. A couple of larger caves on Solomon Island were occupied until the 1950's. (Dowding and Murphy, 1994)

Habitat

Big South Cape Island, adjacent to Solomon Island, rises to 240 m. The shorelines of both islands are rugged and contain numerous caves. The largest of these caves is at Puwai on the south coast of Big South Cape. This cave was occupied by both species of Mystacina until 1965 (Daniel and Baker, 1986). Individuals were also known to roost in seabird burrows. Mystacina robusta individuals probably foraged in moist forest and muttonbird scrub (Olearia) habitats, as do their smaller relatives, M. tuberculata. (Daniel and Baker, 1986)

  • Other Habitat Features
  • caves
  • Range elevation
    140 (low) m
    459.32 (low) ft

Physical Description

Mystacina robusta was a medium-sized and extremely robust bat species. Average size is about one-third larger than their congener, lesser short-tailed bats Mystacina tuberculata. Individuals had stocky bodies with prominent, pointed ears and nostrils and a set of short whiskers. The short tail penetrated the tail membrane on its dorsal surface. The hind legs and feet were very robust, positioned under the body for quadrupedal locomotion on the ground. The fur was dark brown. Mystacina robusta was about 90 mm in total length, with a wingspan of about 290-310 mm. The tail measured approximately 15 mm and the species was estimated to weigh 25-35 g (King, 1990). (King, 1990)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    25 to 35 g
    0.88 to 1.23 oz
  • Range length
    90 (low) mm
    3.54 (low) in
  • Range wingspan
    290 to 310 mm
    11.42 to 12.20 in

Reproduction

Mystacina robusta is thought to have been monogamous. Other information regarding their mating system is not known. To attract females, males of the related species, M. tuberculata, fly to hollow trees and call with a repetitive, high-intensity noise which can be heard by the human ear from a distance of 50 meters. Other details of the breeding of M. tuberculata are not known. (King, 1990)

Little is known about the reproduction of this species. They were thought to breed once a year. The time of breeding is not known since this species of bat is thought to have gone extinct about 40 years ago. J.A. Mackintosh found a juvenile specimen on Solomon Island and also observed several nursery colonies with adolescents in hollow rata trees and in the burrows of sooty shearwaters from late April to mid May of 1963-65 (Lloyd, 2001). This suggests that M. robusta had one young per year, born around April-May. This is approximately four or five months later than the birth season of Mystacina tuberculata. The time of mating and details of the reproductive cycle are not known, although mating by M. tuberculata occurs sometime between February and April. (Daniel and Baker, 1986; Lloyd, 2001; Roberts, 2005)

  • Breeding interval
    Greater short-tailed bats bred once yearly.
  • Breeding season
    This information is not known for Mystacina robusta, but its closest relative, Mystacina tuberculata breeds between February and April
  • Range number of offspring
    1 to 1

No information is available about the parental investment of Mystacina robusta. However, as in other bat species, females would have nursed and cared for their single offspring until they became independent.

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female

Lifespan/Longevity

Information on lifespan/longevity for Mystacina robusta is not available.

Behavior

Greater short-tailed bats emerged from their roosts about 1-2 hours after sunset. They did not fly very fast, and did not manuever as rapidly as little pied bats, and generally they flew within 2-3 m of the ground. It has been suggested that this species of bat did not fly higher because of the thousands of petrels and shearwaters that were flying to their burrows during the breeding season. A close relative, Mystacina tuberculata also flies close to the ground; slow flight therefore appears to be characteristic of the genus Mystacina (Daniel and Baker, 1986). (Daniel and Baker, 1986)

  • Range territory size
    Small, but not known (low) cm^2

Home Range

Not much is known about the home range of Mystacina robusta, but its close relative, Mystacina tuberculata, does not venture much further than 500 m from its roosting site (Daniel and Baker, 1986). (Daniel and Baker, 1986)

Communication and Perception

Mystacina robusta is thought to have gone extinct around 40 years ago. Therefore, no information is known about how it communicated with other bats, or which senses were especially developed. Vision is well developed in the close relative Mystacina tuberculata in order to see the flowers they sometimes feed on. This species also emits a repetitive, high-frequency call that can be heard by the human ear from a distance of up to 50 meters. The hearing of M. tuberculata is also well developed for echolocation in order to locate prey. It is not known how either species of Mystacina communicates with potential mates. (Dowding and Murphy, 1994)

Food Habits

It is not known what exactly the greater short-tailed bat ate. It is believed to have eaten the same wide range of food as its close relative Mystacina tuberculata. These foods include ground and tree-trunk arthropods, fruit, nectar, and pollen. An analysis done on the stomach contents of two greater short-tailed bats revealed the presence of both rata pollen and fern spores (King, 1990). Both species of short-tailed bats were partly carnivorous and ate fat and meat plucked off muttonbirds from time to time. It is also possible that M. robusta ate nestling birds. (Daniel and Baker, 1986; Lloyd, 2001)

  • Animal Foods
  • birds
  • insects
  • terrestrial non-insect arthropods
  • terrestrial worms
  • Plant Foods
  • fruit
  • nectar
  • pollen
  • flowers

Predation

In previous times, some Mystacina robusta may have been killed by laughing owls in the North and South Islands. Rattus exulans is believed to have either caused or assisted the extinction of the greater short-tailed bat in the North and South Islands, as well as Stewart Island. The final extinction of M. robusta is believed to have been caused by ship rats in 1962 and 1963 when they were introduced accidentally on Big South Cape and Solomon Islands (Dowding and Murphy, 19990. (Dowding and Murphy, 1994; Lloyd, 2001)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Mystacina robusta does not play any role in the ecosystem of New Zealand because this species is thought to have been extinct for over 40 years. At one time, M. robusta probably played a role as an insectivore, a pollinator of flowers, and a disperser of seeds.

  • Ecosystem Impact
  • disperses seeds
  • pollinates
Commensal/Parasitic Species

Economic Importance for Humans: Positive

It is not known if or how humans benefited from Mystacina robusta.

Economic Importance for Humans: Negative

There are no known adverse effects of Mystacina robusta on humans.

Conservation Status

It is not known if the effects of ship rats on these bats was the result of predation, competition for food, or continual disturbance of roosting sites. Ship rats readily prey on bats in other areas. Several hundred Mystacina were reported in Puai Cave on Big South Cape, and regular sightings of flying bats were made on both islands as well. In August 1964, the last confirmed M. robusta was collected from Big South Cape. By 1965, there were very few bats at all. J.A. Mackintosh mist-netted the last confirmed M. robusta in 1965 on Solomon Island (Dowding and Murphy, 1999). By 1966, there were no bats on either island. (Dowding and Murphy, 1994)

Mystacina robusta was listed as extinct by the IUCN Red List in 1990. (Dowding and Murphy, 1994)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Brendan Boyes (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

echolocation

The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Daniel, M., A. Baker. 1986. Collins Guide to Mammals of New Zealand. Auckland, New Zealand: William Collins Publishers Ltd..

Dowding, J., E. Murphy. 1994. Ecology of Ship Rats (Rattus rattus) in A Kauri (Agathis Australis) Forest in Northland, New Zealand. New Zealand Journal of Ecology, 18: 19-28. Accessed March 20, 2006 at http://www.nzes.org.nz/nzje/free_issues/NZJEcol18_1_19.pdf.

King, C. 1990. The Handbook of New Zealand Mammals. Auckland, New Zealand: Oxford University Press.

Lloyd, B. 2001. Advances in New Zealand mammalogy 1990-2000: Short-tailed bats. Journal of The Royal Society of New Zealand, 31: 59-81. Accessed March 22, 2006 at https://www.rsnz.org/publish/jrsnz/2001/6.php.

Roberts, J. 2005. Bats and Mankind. New Zealand Journal of Mammals, 23: 327-336.

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