Mystacina robusta, Dwyer, 1962

Don E. Wilson & Russell A. Mittermeier, 2019, Mystacinidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 394-403 : 403

2.

Greater New Zealand Short-tailed Bat

Mystacina robusta

French: Grande Mystacine / German: Grofse Neuseelandfledermaus / Spanish: Murciélago neozelandés grande

Other common names: New Zealand Greater Short-tailed Bat

Taxonomy. Mystacina tuberculata robusta Dwyer, 1962 ,

“Big South Cape Island,” New Zealand.

First described as a subspecies of M. tuberculata but elevated to full species by J. E. Hill and M. J. Daniel in 1985. Monotypic.

Distribution. Might still occur on Big South Cape (= Taukihepa) I and neighboring Putauhina I or on privately owned islands off Stewart I, New Zealand.

Descriptive notes. Total length with tail folded up 70-90 mm, tail 15 mm, ear 17.7-18-6 mm, forearm 45-3-47-5 mm: weight estimated at c. 24 g, although no live specimens have been weighed. Condylo-basal lengths of Greater New Zealand Shorttailed Bats are 21-22-5 mm, wingspans are 290-310 mm, and snout-vent lengths are 65-4-72-4 mm. There is no information on sexual dimorphism. Clinal variation in size might occur, with northern individuals 10-20% larger than those in the south. The Greater New Zealand Short-tailed Bat is overall ¢.33% larger than the Lesser New Zealand Short-tailed Bat ( M. tuberculata ), although with proportionally shorter ears, nostrils, wing elements, and forearms. Pelage is brown and covers body and head;ears, nose, wings, legs, and tail are bare. Skin is gray-brown.

Habitat. Unknown but likely similar to those of the Lesser New Zealand Short-tailed Bat. Greater New Zealand Short-tailed Bats are known to have roosted in caves (only on the mainland) and trees. Muttonbird Islands (some of the last known locations of the species) are granite covered in scrub and a deep mantle of peat, with some broadleaf forest and abundant sea caves.

Food and Feeding. Diets of the Greater New Zealand Short-tailed Bat are likely similar to those of the Lesser New Zealand Short-tailed Bat, with respect to food preferences and consumption of fruit, nectar, pollen, and insects. Stomach content analyses of two museum specimens had pollen of Metrosideros umbellata ( Myrtaceae ) and fern spores. There are historical reports of carnivory, but they are unsubstantiated.

Breeding. Juvenile specimens were collected from Solomon Island in May 1963— 1965. This might suggest that it is polyestrous or that breeding shifted from that of the Lesser New Zealand Short-tailed Bat to coincide with peak insect abundances.

Activity patterns. Estimates of wing loading ratios (based on an estimated body mass of 24-5 g) indicate that the Greater New Zealand Short-tailed Bat is faster and more agile but less maneuverable than the Lesser New Zealand Short-tailed Bat. A report from Solomon Island in 1936 describes removing bats from a tree roost in early summer that were sluggish and cold to the touch, suggesting that it uses torpor as required. Reports indicate that Greater New Zealand Short-tailed Bats emerged from roosts well after sunset (1-2 hours).

Movements, Home range and Social organization. Reports from Solomon Island indicate that Greater New Zealand Short-tailed Bats roosted in large colonies, like the Lesser New Zealand Short-tailed Bat. It reportedly flies low to the ground (less than 2-3 m) similar to the Lesser New Zealand Short-tailed Bat.

Status and Conservation. Classified as Critically Endangered (Possibly Extinct) on The IUCN Red List. The Greater New Zealand Short-tailed Bat is currently listed as data deficient in the New Zealand Threat Classification System. No specimens (alive or dead) have been found on the three main islands since European settlement. Greater New Zealand Short-tailed Bats were only found on the ratfree Muttonbird Islands (off the coast of the Big South Cape Island) and Solomon Island (off the coast of Stewart Island) until the 1960s. Roof Rats (Rattus rattus) arrived on the islands in the 1960s, at which point bat numbers declined rapidly, with the last confirmed sighting in 1967 on Big South Cape Island. There have been unconfirmed reports of bats near the last known populations of Greater New Zealand Short-tailed Bats in the years following rat eradication efforts on Big South Cape Island and Putauhina Island. If it is still present on these or nearby islands, its numbers are presumably very low, probably less than 50 individuals.

Bibliography. Daniel (1990a), Dwyer (1962a), Hill & Daniel (1985), Lloyd (2001, 2005b), Norberg & Rayner (1987), O'Donnell (2008a), O'Donnell et al. (2018), Stead (1936), Worthy & Holdaway (1994b), Worthy et al. (1996).

Figures

Plate 30 Species Accounts

Distribution. Might still occur on Big South Cape (= Taukihepa) I and neighboring Putauhina I or on privately owned islands off Stewart I, New Zealand .