Gloydius blomhoffii (Boie, 1826)

Taxonomy and Naming

Gloydius blomhoffii, first formally described in 1826 by Boie, is a pit viper species native to Japan.

Size

Mature individuals reach an average length of 45–81 cm (17+3⁄4 to 31+7⁄8 inches), while the longest recorded specimen measured 91 cm (36 in).

Body Coloration and Markings

Its body has a base color of pale gray, reddish-brown, or yellow-brown, covered by a series of irregularly shaped lateral blotches. These blotches have black borders and often have lighter-colored centers.

Head Coloration

The head is dark brown or black, with beige or pale gray sides.

Venom Variability in Japan

In Japan, this species’ venom varies very little in both potency and effects.

Venom Toxicity Ranking in Japan

Per a 2005 report by Yoshimitsu, Gloydius blomhoffii and the Okinawan habu (Protobothrops flavoviridis), another pit viper, are the most venomous snakes in Japan.

Venom Lethality

When measured via intraperitoneal injection in mice, the venom’s LD50 lethality ranges from 0.3 mg/kg to 1.22 mg/kg.

Venom Neurotoxin Components

The venom is mostly composed of haemolytic toxins, but also contains two distinct neurotoxins: an alpha-toxin that acts as a post-synaptic inhibitor, and a beta-toxin that acts as a pre-synaptic inhibitor.

Beta-Toxin Treatment Limitation

Because the beta-toxin acts pre-synaptically, its effects cannot be blocked or treated with anticholinesterases.

Additional Venom Compounds

The venom also contains an anticoagulant called mamushi L-amino-acid oxidase (M-LAO), as well as the peptide ablomin.

Ablomin Sequence Similarity

Ablomin shares a highly similar amino acid sequence with helothermine, a venom compound found in the Mexican beaded lizard (Heloderma horridum).

Distribution Range

This species is confirmed to occur in Japan, and Gloyd and Conant note that there is no evidence supporting claims that it lives in the Ryukyu Islands.

Type Locality

Its official type locality is listed simply as "Japan".

Habitat

It occupies a wide range of habitats, including swamps, marshes, meadows, open woodland, rocky hillsides, and montane rock outcroppings.