The copper skink (''Oligosoma aeneum'') is a

skink Skinks are lizards belonging to the family Scincidae, a family in the infraorder Scincomorpha. With more than 1,500 described species across 100 different taxonomic genera, the family Scincidae is one of the most diverse families of lizards. Ski ...

of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Scincidae that is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

Taxonomy and systematics

The number of skink species endemic to New Zealand is not yet known, as advancing molecular studies indicate genetic divergence amongst many groups previously considered a single species. At present, there is estimated to be between 50 and 60 species, all of the family Scincidae. Following a taxonomic revision of the species complex in 2008, the copper skink was assigned the scientific name of ''Cyclodina aenea'', and found to be both genetically and morphologically diverged from two other skink species that were previously considered synonymic.

Anatomy

The copper skink is New Zealand's smallest indigenous skink, with a mature length of no more than 120mm. Like most skinks, it has smooth skin covering a long body, with relatively short legs. The tail makes up a considerable proportion of the body length, and tapers to a point. The skink is capable of shedding its tail to distract predators when threatened, before regenerating a new one – a process known as caudal autotomy. Copper skinks have small heads with round, lidded eyes, which they are capable of blinking.

Ecology and behaviour

The copper skink occupies a range of habitats, from forested areas to urban gardens, and sand dune ecosystems, and farm land. Like many skinks, it has a largely carnivorous diet and feeds mostly on small insects and other invertebrates. Copper skinks are viviparous, and mate in spring before giving birth to between 3-7 relatively large offspring in late summer.

Distribution

The initial arrival of the copper skink (and indeed any other skink species) to New Zealand is somewhat uncertain, and is a topic of considerable debate. The level of genetic diversity between the copper skink and other indigenous species suggests strongly that they and their ancestors have been a part of New Zealand's fauna for millions of years, allowing time for many early species to diverge and become distinct from each other. One 2009 study by Chapple, Ritchie and Daugherty, investigating “the origin and diversification” of New Zealand's skinks, produced a molecular phylogeny by analysing genetic sequences of all but one living species. It suggested that all indigenous New Zealand skinks form a monophyletic group with a single ancestor, and that they initially arrived during the early Miocene era, by clinging to floating debris from New Caledonia. From this early colonisation they underwent adaptive radiation to fill a variety of ecological niches, spreading across New Zealand to form the numerous species known today.

Conservation

Despite the dramatic alteration of New Zealand's landscape by humans, the copper skink has adapted relatively well to urbanisation of its environment. In 2012 the

Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment ...

(DOC) classified the copper skink as Not Threatened under the

New Zealand Threat Classification System The New Zealand Threat Classification System is used by the Department of Conservation to assess conservation priorities of species in New Zealand. The system was developed because the IUCN Red List, a similar conservation status system, had some ...

. It is a common sight in many Auckland gardens, due to its ability to thrive in a range of microhabitats. In the early 1980s (when this species had unprotected status) about a dozen adult Copper Skinks were captured in a park near

Tauranga Tauranga () is a coastal city in the Bay of Plenty region and the fifth most populous city of New Zealand, with an urban population of , or roughly 3% of the national population. It was settled by Māori late in the 13th century, colonised by ...

and released in the Lynmore suburb of

Rotorua Rotorua () is a city in the Bay of Plenty region of New Zealand's North Island. The city lies on the southern shores of Lake Rotorua, from which it takes its name. It is the seat of the Rotorua Lakes District, a territorial authority encompass ...

where there was no natural population. Despite a large domestic cat population the descendants of these relocated Copper Skinks are still present with juveniles regularly found at the original release site (most recent obs July 2020). This demonstrates that relocations of this species into urban gardens can be successful. However, introduced mammalian predators such as cats, rodents and hedgehogs have proven to reduce their population numbers in many regions. In addition to the threat of mammalian predators, there are concerns that the competition for resources between the copper skink and the introduced rainbow skink (''

Lampropholis delicata ''Lampropholis delicata'', the delicate skink, dark-flecked garden sun skink, garden skink, delicate garden skink, rainbow skink or plague skink, or the metallic skink is native to Australia and invasive in New Zealand and Hawaii where it is com ...

'') may present a further threat to copper skink populations.Department of Conservation. (n.d). Rainbow Skinks. Retrieved from A prolific breeder, the rainbow skink occupies a very similar niche to the copper skink in terms of habitat and diet, indicating a significant competition between the species. Despite the concern, there has been relatively little research conducted into the potential effects of rainbow skinks in New Zealand. One 2004 study did compare the condition of captive copper and rainbow skinks housed together with those housed separately, and did not find significant difference between the two. However, due to the high overlap of the species’ resource requirements, the rainbow skink is still considered by many to be a potential threat to copper skink populations.

References

External links

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Neotype specimen of Cyclodina aenea held at the Museum of New Zealand Te Papa Tongarewa
{{Taxonbar, from=Q3350571 Reptiles of New Zealand Oligosoma Reptiles described in 1858 Taxa named by Charles Frédéric Girard