Toxicocalamus


Toxicocalamus is a genus of snakes in the family Elapidae. The genus is endemic to New Guinea.

Description

Most species of Toxicocalamus are relatively small, the largest specimen known being the holotype of the recently described Toxicocalamus ernstmayri, which measures snout-to-vent length and in total length. The second longest is the holotype of T. grandis, which measures SVL, TTL. Most species are under TTL, and several are the thickness of bootlaces. In general females have longer bodies than males, but much shorter tails.

Venom

Members of genus Toxicocalamus are venomous, with fixed front-fangs, but are not known to be a threat to humans, being unaggressive, of modest size, and secretive. However, the venom of T. longissimus is believed to be fairly toxic, since it contains three-finger toxins, Type-I phospholipase A and snake venom metalloproteinase, while T. buergersi possesses long venom glands than extend backwards into the body cavity.

Behaviour

Although most species of Toxicocalamous are believed to be diurnal, they are fossorial, or semi-fossorial, in habit and rarely encountered.

Geographic range

Many species of Toxicocalamus are localised in their distribution and associated with particular islands or mountain ranges. Several species are poorly known, with four known only from their holotypes. Toxicocalamus is probably not closely related to the Australian Elapidae, being endemic to the island of New Guinea, northern coastal offshore islands, i.e. Seleo Is. ; Walis Is. and Tarawai Is., and Karkar Is., and the archipelagoes of Milne Bay Province to the southeast, i.e. d'Entrecasteaux Archipelago, Woodlark Is., and the Louisiade Archipelago.

Diet

The prey of snakes in the genus Toxicocalamus appears to consist almost entirely of earthworms, particularly the giant earthworms of the Megascolecidae, hence the adoption of the term "worm-eating snakes" for species within this genus.

Reproduction

In common with other tropical elapids, Toxicocalamus is believed to reproduce by oviparity, with clutch sizes of 3–7 recorded, dependent on species and size of the female.

Natural history

The natural history of many species of Toxicocalamus is almost entirely undocumented, due to a paucity of specimens and the infrequence of their encounter in the field.

Species

The following 15 species, and single subspecies, are currently recognised as being valid in the genus Toxicocalamus:
Nota bene: A binomial authority in parentheses indicates that the species was originally described in a genus other than Toxicocalamus. These former genera, Apistocalamus, Apisthocalamus, Pseudapistocalamus, Pseudapisthocalamus, Ultrocalamus, and Vanapina, are now synonyms of Toxicocalamus.
The former species Pseudapisthocalamus nymani Lönnberg, 1900; Apisthocalamus pratti Boulenger, 1904; A. loennbergii Boulenger, 1908; and A. lamingtoni Kinghorn, 1928; are synonyms of T. loriae, Vanapina lineata De Vis, 1905 is a synonym of T. longissimus, and Ultrocalamus latisquamatus Schüz, 1929 is a synonym of T. preussi.
Most of the described species are poorly known and rarely encountered. The most widely distributed, and most commonly encountered, species is T. loriae, which accounts for 66% of all Toxicocalamus specimens in museum collections. T. loriae is frequently encountered in the Highlands, where large numbers have been collected in village gardens along the Wahgi River valley of Simbu Province, PNG. The next most frequently encountered and widely distributed species are T. preussi and T. stanleyanus. All the other species are much less well known and localised in distribution.
Also on mainland New Guinea, T. buergersi is known from only six specimens, from the Torricelli Mountains in the Sepik region, PNG; T. spilolepidotus is known from two specimens, from the Kratke Range, Eastern Highlands Province, PNG; T. pachysomus is known from its holotype, from the Cloudy Mountains, Milne Bay Province; PNG, T. cratermontanus from its holotype, from Crater Mountain, Simbu Province, PNG, while T. ernstmayri was only known from its holotype in the Star Mountains of Western Province, PNG, until a second specimen was observed crawling across mine-workings at the Ok Tedi Mine, in the Star Mountains. Toxicocalamus grandis is also only known from its holotype, collected on the Setakwa River, western New Guinea, in 1912,, and T. pumehanae is also only known from its holotype, from the Managalas Plateau, Oro Province, PNG,.
On the islands of Milne Bay, T. holopelturus is known from 19 specimens from Rossel Island, also known as Yela; T. misimae is known from six specimens from Misima Island; and T. mintoni is only known from its holotype, from Sudest Island, also known as Vanantai or Tagula Island, all in the Louisiade Archipelago. Toxicocalamus nigrescens is only known from its holotype and paratype, from Fergusson Island, in the d'Entercasteaux Archipelago, while T. longissimus is known from 12 specimens from Woodlark Island.