Scolopendra morsitans

Scolopendra morsitans was first described by Carl Linneaus in his book 10th edition of Systema Naturae in 1758 and has since retained its original scientific name.[12] The species was nominated as the type species of the centipede family Scolopendra in a submission to the International Commission on Zoological nomenclature in 1955 which was approved two years later.[12][13] The name ‘Scolopendra’ is derived from a Greek term meaning ‘biting earthworms’ which was first used by Aristotle in his book Historia Animalium to refer to aquatic polychaetes and terrestrial centipedes.[14] The word ‘morsitans’ means ‘that bites’ in Latin[15], a name that is shared with a species of tsetse fly (Glossina morsitans).

There are two recognised subspecies of S. morsitans—Scolopendra morsitans morsitans, which was first described by Charles Linnaeus in 1758 to refer to a species locality in India,[6] and Scolopendra morsitans coerulescens, which was described by Francis Cragin and refers to a species locality first found in Kansas in the United States of America.[6] The species is monophyletic and occupies a clade with Scolopendra pinguis, which is the most closely related member of the family Scolopendra to S. morsitans.[9]

Scolopendra morsitans.

Tanzanian blue ringlegs have been recorded to grow to lengths of up to 127 mm in Australian populations,[8] though in other regions, including Southeast Asia, they rarely exceed 100 mm.[5] Because S. morsitans populations differ greatly in colouration, using colour alone to identify the species can be misleading.[5] However, adults are generally characterised by a bright red head and brownish body with distinct striations between each body segment. Juveniles lack clear stripes and often have a head of a similar colour to their body trunk.[8][9] In field observations, the species can sometimes be distinguished from other Scolopendras by its relatively thick rear legs (known as ultimate legs).[8]

In North-western Thailand, adult Tanzanian blue ringlegs have dark blackish heads and ultimate legs,[5] whilst in Northeast Thailand and Cambodia the centipedes have bright red heads and ultimate legs.[5] Similar variations in colour have been observed across Australia and Africa.[5][8] The centipede’s antennae typically have 18-20 segments (occasionally 17 or 21-23), with the 5-7 segments closest to the head having dorsally facing hairs and the next 5-8 having ventrally facing hairs.[5][8] Their tooth plates contain 5-6 teeth. Body segments 7-20 contain visible lines (known as paramedian sutures) surrounding the centre of the trunk, while the final segment of the centipede has a central line known as a medial suture.[5][8] The centipede does not display obvious sexual dimorphism so subtle differences between the lateral margins of the tergites of male and female individuals are used as a determinant of sex.[8]

The Tanzanian blue ringleg occupies a cosmopolitan distribution,[10][16] and is found across all major continents; however, it has not been widely documented in Europe.[16] It is thought to be native to the majority of continental Australia (with the exception of Victoria, South Australia and SouthWest Western Australia), Africa (except for the Eritrean highlands and Red Sea Hills), most of South and South East Asia, Madagascar and Sri Lanka.[16] The centipede has been introduced to much of the Americas, with sightings outside its native range in Peru, Mexico, Argentina, the Bahamas, Argentina and the Southern United States of America.[16] It has been proposed that the preference of red-headed centipedes for habitats similar to the conditions on ships has resulted in their widespread invasion of inhabited areas.[16]

The species occupies a diverse range of habitats, from the arid and semi-arid outback of Australia to the diverse tropics and temperate zones of India and tropical rainforests of Southeast Asia.[5] Tanzanian blue ringlegs have a preference for warmer climates and the range of the centipede appears to be limited by this affinity.[8] Individual populations of Tanzanian blue ringlegs are known to differ in physical characterists based on their local geographical distributions,[5][8][9] this has prompted the creation of over 50 synonyms for S. morsitans in scientific literature largely due to misidentification of location specific populations of the species.[9][17]

To begin reproduction, the male spins a small web.[18][19] This web-spinning is quite common across all centipedes.[20] The male then deposits a bean-shaped package of sperm on the web, which the female later picks up with her genitals.[21] Their brood chambers are typically found under rocks and stones,[19] and can be up to 10 cm deep.[21] Females can lay up to 86 greenish eggs in such chambers.[19] The female will curl around the eggs until they hatch[21].They take 4 years to mature, and can live a total of 10. This life span is not unusual for a centipede- Scolopendra subspinipes can also live up to ten years.[22]

Tanzanian blue ringlegs, along with other centipedes of the genus Scolopendra, are known to use their ultimate legs in threat displays—raising the appendages aggressively when approached from behind.[23] This behaviour is thought to be a form of automimicry, confusing potential predators by disguising their vulnerable flanks as their fang-bearing heads.[24]

They feed on other arthropods, such as spiders and small insects,[25] and cockroaches.[26] When in captivity, they may feed on small vertebrates (mice, frogs, etc.)[19].