Cyriopagopus

Physical description and identification

Cyriopagopus is a genus of Old World burrowing tarantulas in the family Theraphosidae, infraorder Mygalomorphae. Eugène Simon described it in 1887; in 2015 the better-known name Haplopelma was synonymised with it, which is why so many older books and labels call these spiders Haplopelma. Around fifteen species are currently recognised, including the cobalt blue (C. lividus), the Thailand zebra leg (C. albostriatus) and the purple earth tiger (C. sp. "hati hati").

Adults

• Size: adult females have a body length of roughly 5.3–8.5 cm (2.0–3.3 in), with a leg span commonly in the 12–20 cm range depending on the species. Males mature smaller and lighter with proportionally longer legs.
• Colour: most species are a plain light to dark brown with a velvety sheen. The exceptions are famous: C. lividus has legs of intense metallic blue, and C. albostriatus carries crisp pale stripes along the legs and abdomen. Note that the cobalt blue is correctly Cyriopagopus lividus — the combination Haplopelma lividum still in wide circulation is the old name.
• Eyes: eight small eyes on a low tubercle at the front of the carapace, with very limited vision.
• Distinctive features: heavy fangs — up to about a centimetre in a large female — a compact, powerful build for digging, and, crucially, no urticating setae. Old World tarantulas cannot throw irritant hairs. Mature males have swollen palpal bulbs and are far more likely than females to be seen in the open.

Eggs and egg sac

The female lays pale, rounded eggs on a silk mat deep inside the burrow and folds it into a sac that she keeps underground, turning it and defending it aggressively. Clutches run to several hundred eggs, and because it all happens out of sight, wild egg sacs are rarely observed.

Spiderlings

Spiderlings are plain brown, with none of the adult colour, and remain in or beside the maternal burrow before digging their own. From that point they are solitary, and growth comes in steps at each molt — the blue of a young C. lividus deepening as it goes.

The burrow and hunting

These are obligate burrowers — fossorial in the strict sense — and they spend the overwhelming majority of their lives underground. A burrow can run half a metre or more into a bank or forest floor, the walls papered in silk and a heavy silk collar laid at the entrance. That collar is not a snare; it telegraphs footsteps and keeps the tunnel from collapsing. Prey is ambushed from the entrance and hauled inside before it can struggle free.

Where Cyriopagopus tarantulas live

The genus is Southeast Asian. Its core range runs from Myanmar and southern China, including Hainan, through Thailand, Laos, Cambodia and Vietnam, south into Peninsular Malaysia and across to Borneo. Popular accounts sometimes extend the range as far as the Philippines; the eastern limit of the genus is better treated as unsettled, since the taxonomy of Asian theraphosids is still being revised.

Habitat is tropical forest, forest edge, plantation ground and vegetated hill slopes — anywhere the soil holds a tunnel. Steep banks and road cuttings are favoured, offering drainage and a vertical face to dig into. A fossorial tarantula regulates heat and humidity by moving up and down its own burrow, which stays damp and cool when the surface is baking.

Because they stay underground, these spiders are far more common in many areas than sightings suggest. What people meet is usually a wandering male, or an animal flooded out by heavy rain.

Are Cyriopagopus tarantulas venomous?

Yes, and here the answer needs more care than it does for a New World tarantula. No tarantula venom is lethal to a healthy adult human, no death has ever been attributed to one, and there is no antivenom for any theraphosid because none is required. But "not lethal" is not the same as "harmless", and the Old World species are the ones that prove it.

Cyriopagopus has no urticating setae — the barbed hairs that a Grammostola or a Brachypelma flicks off its abdomen. Lacking that first line of defence, Old World genera evolved in the other direction: they are quicker, more willing to stand and threaten, and their venom produces markedly stronger local effects. Bites by Asian theraphosids are reported to cause severe pain out of proportion to the wound, swelling lasting days, and sometimes muscle cramping in the bitten limb — effects also documented for Old World groups such as Poecilotheria and the African Pterinochilus.

Can Cyriopagopus tarantulas bite?

They can, and they are among the tarantulas most likely to. A cornered Cyriopagopus gives a clear warning first: it rears back onto its hind legs, lifts the front pair, and opens fangs that can exceed a centimetre. If the threat continues it strikes, often repeatedly, and it is fast enough that the strike is usually over before the person has moved.

What a bite does: immediate, severe pain far beyond what the two puncture marks suggest; swelling and redness spreading around the site; sometimes numbness, sweating, nausea or cramping of the muscles in the bitten limb. Symptoms typically peak within hours and fade over one to several days. There is no reported human fatality, but there is no reason to tough it out either.

What to do: wash the wound with soap and water, apply a cold pack, keep the limb still and elevated, and take simple analgesia. Seek medical care if the pain is severe, if cramping or systemic symptoms develop, if redness spreads over the following days, or if there are signs of an allergic reaction. Photograph the spider rather than trying to catch it. Do not cut, suck, tourniquet or apply any home remedy to the wound.

Ecological importance and behavior of Cyriopagopus tarantulas

Cyriopagopus is a nocturnal, solitary ambush predator that almost never leaves its burrow voluntarily. It sits just inside the entrance after dark with its front legs on the silk collar and takes crickets, roaches, beetles, grasshoppers and other ground invertebrates; large females occasionally take small frogs, lizards or rodents that stray too close.

Natural predators: pompilid spider wasps are the specialists, paralysing an adult tarantula and sealing it with an egg. Large birds, monitor lizards, snakes, civets and other mammals take spiders caught above ground, and parasitic flies and nematodes attack them below it. Ants are a serious threat to a female with an egg sac.

Prey-predator dynamics: burrowing tarantulas remove a steady volume of ground insects from plantation and forest soils, and abandoned burrows become refuges for frogs, geckos and invertebrates.

Seasonal behaviour: mature males abandon their burrows and travel in search of females, mostly in the wet season, and this is when almost all human encounters happen. Females continue to molt and commonly live twelve to twenty years; males rarely survive a year past their final molt, giving a total male lifespan of roughly three to five years.

Relationship with humans: these tarantulas are not a public health problem and they eat pest insects, but they are not animals to be picked up. They are also popular in the pet trade, where their speed and defensiveness make them a species for experienced keepers, and where wild collection pressures local populations.

Species in the genus and similar tarantulas

Quick facts

Did you know?

• Eugène Simon erected Cyriopagopus in 1887, five years before he named Haplopelma. When the two proved to be one genus in 2015, the older name won — which is why so many "Haplopelma" labels are out of date.
• The cobalt blue's colour is structural: nanostructures in the leg hairs scatter blue light rather than pigment producing it, the same mechanism seen in several unrelated tarantula lineages.
• "Earth tiger" is the trade name for these Asian burrowers, and it fits — fast, striped in some species, and rarely seen above ground.
• A wild Cyriopagopus may spend years without leaving its tunnel. Most photographs of one in the open show a wandering male or a flooded-out animal.
• Having no urticating hairs is not a disadvantage, just a different solution: Old World tarantulas invested in speed, threat display and a bite that hurts.

In summary, Cyriopagopus is the Old World counterweight to the gentle New World giants. These are fast, deep-burrowing Southeast Asian tarantulas with no irritant hairs and no inclination to run far. Their bite will not kill a person, but it hurts badly enough that the right approach is a photograph and a respectful distance.