Scientific identify: Onychophorans 
Scientific classification:
Phylum: Onychophora
Class: Onychophora
Order: Onychophorida
Family: Peripatidae and Peripatopsidae

What do they appear to be?
The velvet worms appear to be slugs with legs. They have an extended physique with 14 to 43 pairs of stubby legs (relying on the species and intercourse) and on the head finish there's a pair of antennae. The pores and skin of the animal appears to be like relatively velvety, therefore the frequent identify. They vary in dimension from 1.4 to 20 cm. Most of the species are comparatively small.

Where do they stay?
All of these animals are discovered within the Southern Hemisphere. They are recognized from the tropical areas, such because the East Indies, the Himalayas, the Congo, the West Indies, northern South America and temperate areas, together with Australia, New Zealand, South Africa, and the Andes. Although their distribution encompasses a variety of climatic zones they're all the time present in affiliation with cool, moist microhabitats.

Characteristics

The velvet worms have been first described in 1826 and on the time they have been thought to be associated to the slugs, snails, and different mollusks. Today, way more is understood about these animals, however they nonetheless arouse curiosity due to their fascinating biology. All velvet worms are predators and they catch their prey in a really fascinating manner. Most species emerge from their daytime hideaways to hunt for prey within the humid cool of the evening. They amble alongside on their quick, fats legs utilizing the sensory organs of their antennae to detect the faint indicators of their prey, which incorporates absolutely anything smaller than themselves. When they decide up the scent of their prey they may observe the path till they're virtually on prime of their quarry. Their eyesight just isn't the perfect, however their sense of odor and contact are very properly developed. Ready to strike, the velvet worm can make use of its secret weapon. Either facet of the velvet worm’s mouth there's a small fl eshy turret. These lumps are linked to massive glands contained in the animal that produce a sticky slime. With the prey in its sights, the velvet worm rears up and squirts two streams of slime on the unlucky prey. Thisslime will be squirted up to 30cm and virtually instantly it begins to harden, entangling the prey in a internet of sticky threads. With the prey incapacitated, the velvet worm ambles over to it and begins to feed by passing toxic saliva into the physique of the animal, which begins the digestion course of. The velvet worm then sucks the partially digested tissues into its mouth. Apart from their superb feeding conduct, some species of velvet worm have additionally developed a singular manner of fertilizing their eggs. The males of these species crawl over the feminine’s physique and deposit a small packet of sperm (spermatophore) randomly on her facet or again. Over time a feminine could accumulate a number of such packets from quite a lot of males. Somehow, the spermatophores set off blood cells inside the feminine to dissolve the underlying pores and skin, permitting the sperm to escape from their parcel into the physique cavity of the feminine. Free within the feminine’s blood the sperm should swim for the feminine’s sperm storage organs, the place fertilization will happen. This just isn't the one complexity within the reproductive conduct of this animal. Some species lay eggs. Other species produce eggs that hatch inside the feminine’s physique. Just a few species of velvet worm have distributed with shelled eggs altogether and give beginning to stay younger. These younger are nourished inside the feminine’s physique by a secretion produced by the uterus, which reaches the younger both by way of a particular membrane or a direct placental-like connection to the uterine wall.

Key Facts

  • There are 110 described species of velvet worm. Their look suggests they're dwelling fossils which have remained basically unchanged for a whole bunch of hundreds of thousands of years. Fossils, a minimum of 500 million years outdated, have been discovered exhibiting the impressions of marine animals that look strikingly comparable to the dwelling velvet worms. The earliest fossil exhibiting what seems to be a terrestrial velvet worm is roughly 300 million years outdated. The areas the place these animals are discovered additionally point out nice antiquity. The continents within the southern hemisphere have been as soon as joined in a single gigantic landmass, generally known as Gondwanaland, however the continents, sitting on their big continental plates drifted away from each other, carrying their dwelling cargo with them to give us the association of the continents we see right this moment and uncommon distributions of the surviving historical animals.
  • There are two households of velvet worm and they've totally different distributions. The peripatids are predominantly equatorial and tropical whereas peripatopsids are all present in what used to be Gondwanaland.
  • Because of their nice antiquity, the velvet worms are regarded with nice curiosity by these scientists who examine how diff erent animals are associated. The velvet worms possess traits that make some people suppose they're carefully associated to the annelid worms, however different traits recommend a better affinity with the arthropods (bugs, spiders, crustaceans and many others). Some even suppose they symbolize a so-referred to as lacking hyperlink between the annelids and arthropods. Recent findings level to the velvet worms being extra carefully associated to the arthropods than they're to the annelids. Only time and additional investigations will reveal the true relationships of the velvet worms.
  • Recently, it has been discovered that some velvet worms are able to advanced social conduct. Groups of round 15 people dominated by an grownup feminine, stay, hunt and feed collectively. An animal’s place inside the group is set by bouts of combating.
  • The pores and skin of the velvet worms incorporates the substance generally known as chitin, which is discovered within the pores and skin of arthropods. As this materials doesn't stretch, an animal with a chitin containing overlaying should periodically shed its pores and skin. In velvet worms this may happen as usually as each 10 days.
  • Velvet worms, not like many invertebrates have fairly an extended life span, a minimum of six years in some species.
  • The velvet worms are restricted to humid environments or solely emerge in the course of the evening when it's cool and humid. One of the explanations for this restriction is that the respiratory equipment of the velvet worm, the trachea, are open to the air, with none type of valve that conserves moisture. Arthropods, like bugs have closeable spiracles limiting their water loss.