Woodworthia "Otago/Southland large"

Kōrero gecko

Woodworthia "Otago/Southland large"

Kōrero geckos (Otago). <a href="https://www.instagram.com/samanimalman/">© Samuel Purdie</a>
Image attribution
Kōrero geckos (Otago). © Samuel Purdie
Herpetofaunal category
NZ Geckos
Species complex
Conservation Status
At Risk - Declining
Previous scientific names
Hoplodactylus maculatus
Common names
Kōrero gecko,
Otago large gecko.

Length: SVL up to 95mm, with the tail being longer than the body length

Weight: unknown

Description

A beautiful and robust species of Woodworthia with a snout-vent-length (SVL) up to 90 mm. Kōrero geckos typically have a brown or grey dorsal surface with blotches, chevrons, or longitudinal stripes. The lower surfaces of the mouth and tongue are pink; the tongue tip is often a diffuse grey. The rostral scale contacts (or nearly) contacts the nostrils. This species comprises three distinct geographic groups, which may one day be described as different species:

1. Northern Raggedy Range group:

SVL up to 68 mm. Found exclusively in the northern Raggedy Range. Dorsal surface typically dark grey and marked with blotches or chevrons. Ventral surface typically pale and speckled in some individuals. Eye colour brown with yellow mottling. Iris ranges from as described through to bright green-yellow. Eye is noticeably smaller than in schist gecko (Woodworthia "Central Otago"). Toes moderately expanded and broadest near tip; distal phalanges are relatively short.

2. Western group:

SVL up to 90 mm. Found from the lowlands to high altitude areas bounded by the Clutha Valley, Kawarau Valley, Wakatipu, and Waimea Plains. Also found in Fiordland mountains. Dorsal surface typically grey, olive-grey, or dark pinkish-brown and marked with blotches, chevrons, or longitudinal stripes (very rarely). Ventral surface typically pale and speckled in some individuals. Eye colour green, brown (or in far eastern populations) yellow. Toes broadly expanded with 12-13 subdigital lamellae; distal phalanges very short. Three rows of precloacal pores extending onto legs, versus only two of the three rows in the eastern and southern group.

3. Eastern and southern group:

SVL up to 95 mm. The most widespread group, found in the Dunstan Mountains, Dansey’s Pass, Kakanui Mountains, Horse Range, and Rock and Pillar Range. Dorsal surface typically brown, grey-brown, or olive-grey and marked with blotches, chevrons, or longitudinal stripes. Ventral surface typically pale and speckled in some individuals. Superficially similar to the western group but with fewer subdigital lamellae (8-13); longer distal phalanges, and two rows of precloacal pores.

Life expectancy

Potentially over 35 years.

Distribution

Found throughout much of Otago, Southland (including islands in Foveaux Straight) and the eastern edges of Fiordland.

Ecology and habitat

Kōrero geckos are terrestrial/arboreal and inhabit beech forest, podocarp/hardwood forests, rocky grasslands, and rocky alpine areas up to 1300 m (Jewell 2008) Often forms large aggregations in retreats when populations are dense. Individuals may vocalize with a chittering sound (hence their colloquial name). Kōrero geckos are recognised as a nocturnal species but exhibit a range of diurnal behaviours including basking in partial concealment, overt basking, and specific postural adjustments (Gibson et al. 2015; Gibson 2013). This is most likely to aid in thermoregulation and, in pregnant females, may result in a decreased gestation period (Gibson et al. 2015).

Social structure

A highly gregarious species that can sometimes be found in astounding densities. They can engage in antagonistic conspecific behaviour, however, typically live in large aggregations and are thus, tolerant of one another.

Breeding biology

Viviparous. Gestation approximately 14 months. Mating typically occurs in February and females store sperm over winter. Vitellogenesis (yolk deposition) typically occurs from midsummer to autumn and ovulation occurs the following spring. Embryos become fully developed by early autumn (Rock and Cree 2008; Rock 2006). In high-altitude populations, females typically breed biennially and produce up to two young in November. In lowland populations, females typically breed annually and produce up to two young in early February (van Winkel et al. 2018; Chapple 2016; Jewell 2008; Cree et al. 2003; Cree and Guillette. 2003).

Diet

Predominantly insectivorous, however, will also consume fruit and nectar sources. 

Disease

Unknown. 

Conservation strategy

This species is not currently being managed by the Department of Conservation. However, in the event land is developed/destroyed, mitigation is undertaken, whereby geckos are salvaged and relocated to appropriate habitat. 

Interesting notes

Kōrero geckos are members of the 'common gecko' complex, a group of closely related species which are regionally distributed throughout New Zealand. Historically, most of these were considered a single highly-variable species - Hoplodactylus maculatus (the so called 'common gecko'). The 'common gecko' has now been separated into over ten different species.

References

Bell, T. (2014). Standardized common names for New Zealand reptiles. BioGecko, 2, 8-11.

Chapple, D. G. (2016). Synthesising our current knowledge of New Zealand lizards. New Zealand Lizards (pp. 1-11). Springer, Cham.

Cree, A., Guillette, LJ Jr. (1995) Biennial reproduction with a fourteen-month pregnancy in the gecko Hoplodactylus maculatus. Southern New Zealand Journal of Herpetology 29:163–173.

Cree, A., Tyrrell, CL., Preest, MR., Thorburn, D., Guillette, LJ Jr. (2003) Protecting embryos from stress: corticosterone effects and the corticosterone response to capture and confinement during pregnancy in a live-bearing lizard (Hoplodactylus maculatus). General and Comparative Endocrinology 134:316–329.

Gibson, S. (2014). Basking behaviour of a primarily nocturnal, viviparous gecko in a temperate climate (Doctoral dissertation, University of Otago).

Gibson, S., Penniket, S., & Cree, A. (2015). Are viviparous lizards from cool climates ever exclusively nocturnal? Evidence for extensive basking in a New Zealand gecko. Biological Journal of the Linnean Society, 115(4), 882-895.

Jewell, T. (2008). A photographic guide to reptiles and amphibians of New Zealand. Auckland: New Holland.

Rock, J. (2006) Delayed parturition: constraint or coping mechanism in a viviparous gekkonid? Journal of Zoology 268:355–360.

Rock, J., Cree, A. (2003) Intraspecific variation in the effect of temperature on pregnancy in the viviparous gecko Hoplodactylus maculatus. Herpetologica 59:8–22.

van Winkel, D., Baling, M., Hitchmough, R. 2018. Reptiles and amphibians of New Zealand – a field guide. Auckland university press, Auckland New Zealand.

Hitchmough, R., Barr, B., Lettink, M., Monks, J., M., Reardon, J., Tocher, M., van Winkel, D., Rolfe, J. (2015). Conservation status of New Zealand reptiles, 2015. Publishing Team, Department of Conversation, Wellington New Zealand.