Oligosoma aff. polychroma Clade 5

Southern grass skink

Oligosoma aff. polychroma Clade 5

Southern grass skinks. <a href="https://www.instagram.com/samanimalman/?hl=en">© Samuel Purdie</a>
Image attribution
Southern grass skinks variation. © Samuel Purdie
Herpetofaunal category
NZ Skinks
Species complex
Conservation Status
At Risk - Declining
Previous scientific names
Oligosoma polychroma,
Oligosoma nigriplantare polychroma.
Common names
Southern grass skink,
Common skink.

Length: SVL up to 80mm, with the tail being equal to or slightly longer than the body length

Weight: unknown

Description

A very sleek and variable species of grass skink with a snout-vent-length (SVL) up to 80 mm. Southern grass skinks typically have a tan-brown dorsal surface with a dark mid dorsal stripe extending down the tail and conspicuous pale dorsolateral stripes that can be smooth or notched. This species possesses a dark brown lateral band with smooth or notched borders that are usually pale. The ventral surface, including throat and chin, is typically uniform grey, brown, tan-brown, cream, white or yellow. Eye colour is typically brown-tan, sometimes slightly green. This species usually possess a pale stripe on the forelimbs. Subdigital lamellae 16-24 (van Winkel et al. 2018; Jewell 2008) . 

Life expectancy

Unknown.

Distribution

A very widespread species of grass skink. Found in Otago, Southland, Central and southern Canterbury (incl. on Banks Peninsula), and Foveaux Strait (incl. Stewart Island). This species is also found at a variety of elevations from lowland coastal areas, right up into the mountains. 

Ecology and habitat

Southern grass skinks are a very frequently seen species because they are diurnal, avid sun-baskers, and terrestrial. This species has been recorded in densities as high as 4000 per hectare (Wilson et al. 2017). Southern grass skinks inhabit a range of habitats including coastal dune habitat, wetlands, grassland, shrublands, rocky shrubland/herbfield, screes, tussock, stony river beds and even cities.

Social structure

Unknown.

Breeding biology

This species reproduces annually and is mature at about 3 years old. Mating likely takes place around March, with 3-6 offspring born in the summer months (November-February) (van Winkel et al. 2018).

Diet

Feeds on small invertebrates and small fruits/sugar sources. 

Disease

Southern grass skinks are known hosts for the ectoparasitic mites Odontacarus lygosomae, and Ophionyssus scincorum, as well as the blood parasite Hepatozoon lygosomarum.

Conservation strategy

This species is not being actively managed. However, when land is developed/destroyed, this species is often salvaged and relocated to suitable habitat. This species is also present at a number of predator-resistant sanctuaries. 

Interesting notes

This species has been observed occupying insect burrows.

Southern grass skinks are members of a cryptic species complex which includes the northern grass skink (Oligosoma polychroma), Waiharakeke grass skink (Oligosoma aff. polychroma Clade 2), south Marlborough grass skink (Oligosoma aff. polychroma Clade 3), and Canterbury grass skink (Oligosoma aff. polychroma Clade 4). The various species are regionally distributed, similar in both appearance and habit, and were once regarded as a single highly variable species - the 'common skink'. There are currently no known morphological features to distinguish southern grass skinks from the other species within the complex. 

References

Allison, B., & Desser, S. S. (1981). Developmental stages of Hepatozoon lygosomarum (Doré 1919) comb. n.(Protozoa: Haemogregarinidae), a parasite of a New Zealand skink, Leiolopisma nigriplantare. The Journal of Parasitology, 852-858.

Batson, W. G., O’Donnell, C. F., Nelson, N. J., & Monks, J. M. (2015). Placement period of artificial retreats affects the number and demographic composition but not the body condition of skinks. New Zealand Journal of Ecology39(2), 273-279.

Chapple, D. G., Ritchie, P. A., & Daugherty, C. H. (2009). Origin, diversification, and systematics of the New Zealand skink fauna (Reptilia: Scincidae). Molecular phylogenetics and evolution52(2), 470-487.

Chavel, E. E., Hoare, J. M., Batson, W. H., & O'Donnell, C. F. J. (2012). The effect of microhabitat on skink sightings beneath artificial retreats. New Zealand Journal of Zoology39(1), 71-75.

Cree, A. (1994). Low annual reproductive output in female reptiles from New Zealand. New Zealand journal of zoology21(4), 351-372.

Daugherty, C. H., Patterson, G. B., Thorn, C. J., & French, D. C. (1990). Differentiation of the members of the New Zealand Leiolopisma nigriplantare species complex (Lacertilia: Scincidae). Herpetological monographs, 61-76.

Fischer, J. H., McCauley, C. F., Armstrong, D. P., Debski, I., & Wittmer, H. U. (2019). Contrasting responses of lizard occurrences to burrowing by a critically endangered seabird. Community Ecology20(1), 64-74.

Frank, H., & Wilson, D. J. (2011). Distribution, status and conservation measures for lizards in limestone areas of South Canterbury, New Zealand. New Zealand Journal of Zoology38(1), 15-28.

Freeman, A. B. (1997). Comparative ecology of two Oligosoma skinks in coastal Canterbury: a contrast with Central Otago. New Zealand Journal of Ecology, 153-160.

Hardy, G. S. (1977). The New Zealand Scincidae (Reptilia: Lacertilia); a taxonomic and zoogeographic study. New Zealand journal of zoology4(3), 221-325.

Hitchmough, R., Barr, B., Knox, C., Lettink, M., Monks, J. M., Patterson, G. B., Reardon, J. T., van Winkel, D., Rolfe, J., & Michel, P. (2021). Conservation status of New Zealand reptiles, 2021New Zealand threat classification series 35. Wellington: New Zealand Department of Conversation.

Hoare, J. M., O'Donnell, C. F., Westbrooke, I., Hodapp, D., & Lettink, M. (2009). Optimising the sampling of skinks using artificial retreats based on weather conditions and time of day. Applied Herpetology6(4), 379.

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

Jones, C., Moss, K., & Sanders, M. (2005). Diet of hedgehogs (Erinaceus europaeus) in the upper Waitaki Basin, New Zealand: implications for conservation. New Zealand Journal of Ecology, 29-35.

Jones, C., Norbury, G., & Bell, T. (2013). Impacts of introduced European hedgehogs on endemic skinks and weta in tussock grassland. Wildlife Research40(1), 36-44.

Lettink, M., & Cree, A. (2007). Relative use of three types of artificial retreats by terrestrial lizards in grazed coastal shrubland, New Zealand. Applied Herpetology4(3), 227-243.

Lettink, M., O'Donnell, C. F., & Hoare, J. M. (2011). Accuracy and precision of skink counts from artificial retreats. New Zealand Journal of Ecology, 236-246.

Lettink, M., & Seddon, P. J. (2007). Influence of microhabitat factors on capture rates of lizards in a coastal New Zealand environment. Journal of Herpetology41(2), 187-196.

Liggins, L., Chapple, D. G., Daugherty, C. H., & Ritchie, P. A. (2008). A SINE of restricted gene flow across the Alpine Fault: phylogeography of the New Zealand common skink (Oligosoma nigriplantare polychroma). Molecular Ecology17(16), 3668-3683.

Lord, J. M., & Marshall, J. (2001). Correlations between growth form, habitat, and fruit colour in the New Zealand flora, with reference to frugivory by lizards. New Zealand Journal of Botany39(4), 567-576.

Mockett, S. (2017). A review of the parasitic mites of New Zealand skinks and geckos with new host records. New Zealand journal of zoology44(1), 39-48.

O’Donnell, C. F., & Hoare, J. M. (2012). Monitoring trends in skink sightings from artificial retreats: influences of retreat design, placement period, and predator abundance. Herpetological Conservation and Biology7(1), 58-66.

O’Donnell, C. F., Weston, K. A., & Monks, J. M. (2017). Impacts of introduced mammalian predators on New Zealand’s alpine fauna. New Zealand Journal of Ecology41(1), 1-22.

Patterson, G. B., & Daugherty, C. H. (1990). Four new species and one new subspecies of skinks, genus Leiolopisma (Reptilia: Lacertilia: Scincidae) from New Zealand. Journal of the Royal Society of New Zealand20(1), 65-84.

Patterson, G. B., & Daugherty, C. H. (1995). Reinstatement of the genus Oligosoma (Reptilia: Lacertilia: Scincidae). Journal of the Royal Society of New Zealand25(3), 327-331.

Reardon, J. T., & Norbury, G. (2004). Ectoparasite and hemoparasite infection in a diverse temperate lizard assemblage at Macraes Flat, South Island, New Zealand. Journal of Parasitology90(6), 1274-1278.

Reardon, J. T., & Tocher, M. (2003). Diagnostic morphometrics of the skink species, Oligosoma maccanni and O. nigriplantare polychroma, from South Island, New Zealand. Wellington: Department of Conservation.

Spitzen–van der Sluijs, A., Spitzen, J., Houston, D., & Stumpel, A. H. (2009). Skink predation by hedgehogs at Macraes Flat, Otago, New Zealand. New Zealand Journal of Ecology, 205-207.

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

Walker, S., Wilson, D. J., Norbury, G., Monks, A., & Tanentzap, A. J. (2014). Effects of secondary shrublands on bird, lizard and invertebrate faunas in a dryland landscape. New Zealand Journal of Ecology, 242-256.

Wiedemer, R. L., Wilson, D. J., Mulvey, R. L., & Clark, R. D. (2007). Sampling skinks and geckos in artificial cover objects in a dry mixed grassland—shrubland with mammalian predator control. New Zealand Journal of Ecology, 169-185.

Wilson, D. J., Mulvey, R. L., Clarke, D. A., & Reardon, J. T. (2017). Assessing and comparing population densities and indices of skinks under three predator management regimes. New Zealand Journal of Ecology41(1), 84-97.

Wotton, D. M., Drake, D. R., Powlesland, R. G., & Ladley, J. J. (2016). The role of lizards as seed dispersers in New Zealand. Journal of the Royal Society of New Zealand46(1), 40-65.