Snake (Banded Sea Krait) Laticauda colubrina

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Elapidae
Genus: Laticauda
Species: L. colubrina
Binomial name: Laticauda colubrina
Common names: Yellow-lipped sea krait, Colubrine sea krait, Banded sea krait

Laticauda colubrina is a species of venomous sea snake usually found in tropical South-east Asia, New Guinea, Australia and Pacific Islands. It is rare for them to be sighted in New Zealand. They arrive here naturally from time to time on ocean currents. The last recorded sighting was in June 2018 swimming in the Tauranga Bridge Marina. Laticauda colubrina was first recorded in New Zealand in 1880. 
According to the Department of Conservation, they are considered a native species under the Wildlife Act 1953. This is because they arrive here naturally from time to time on ocean currents (rather than by human transportation). It is, therefore, illegal to kill or harass any sea snake or possess one or any part of one without a permit.
Sea snakes are highly venomous with a very potent neurotoxic venom which it uses to prey on eels and small fish. They are docile creatures and usually only bite in self-defence when accidentally grabbed. There is no record of anyone in New Zealand being bitten. Nevertheless, if you find a sea snake keep well away and call 0800 DOC HOT.

Laticauda colubrina males have a total length of 875 mm, with a 130 mm long tail. Females are significantly larger, with an average total length of 1,420 mm and a tail length of 145 mm. The tail is paddle-like and is used for swimming.
The snake's upper body surface is a shade of blueish grey, while the belly is a yellowish colour. There are wide ventral scales that stretch from a third to more than half of the width of the body. There are distinctive black stripes are present throughout the length of the snake, but the rings narrow or are interrupted at the belly. 
The head of a banded sea krait is black, with lateral nostrils and an undivided rostral scale. The upper lip and snout are characteristically coloured yellow, and the yellow colour extends backwards on each side of the head above the eye to the temporal scales.
Laticauda colubrina spends much of its time underwater in order to hunt, but returns to land to digest, rest, and reproduce. It is on land humans can encounter them. Overseas they are frequently found in the water intake and exhaust pipes of boats.

Watch a video of Dr Brian Gill, curator of land vertebrates discusses New Zealand's sea snakes 
https://www.youtube.com/embed/Q4PZQBeOsIU

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Photo shows why one of its common names is the Yellow-lipped sea krait, The upper lip and snout are characteristically coloured yellow, and the yellow colour extends backwards on each side of the head above the eye.[2]

Distribution map of past sightings
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Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/