Tarantulas Flashcards
Tarantulas belong to the arthropod group.
There are how many tarantula species?
900 species all over the world.
In the past they have been used for food, in cosmetic industry, in mythology, in art,
commerce, in research, in pranks.
The males have a shorter life span than females of the same species.
Describe tarantula exsoskeleton anatomy.
Defines the shape of the tarantula
Points of attachment for muscles
Impedes water loss
Serves as an armor
Barrier to infectious agents
Exoskeleton extensions are sensory structures
They also have a small endoskeleton which aids in muscle attachments in the body.
Describe tarantula anatomy.
Arachnids consist 2 major body parts, the prosoma and opisthosoma.
Both are attached to each other by a thin and flexible pedicle, through which circulatory, digestive and nervous systems are canalized, surrounded by a complex musculature.
Each spider has 8 legs and every leg consists of 7 segments.
The prosoma of a tarantula is
also known as a cephalothorax
The anterior (or front) major body segment, literally a fusion of the head and thorax.
On the dorsal side of the prosoma there is
the carapace.
Subdivided in the anterior cephalic region
(containing the eyes) and the posterior thoracic region.
The shape and the surface texture of the
carapace and its components, such as
hairiness and the shape of the fovea, are
proven to be taxonomic features of big
importance.
Describe spider eyesight.
Except for a few cave-dwelling species all
spiders are equipped with a set of eyes.
Nevertheless spiders often suffer poor eyesight.
The basal segment, which attaches the legs to the spider’s body is the
coxa.
It is followed by trochanter, femur, patella, tibia, metatarsus and tarsus and in the end there are 2 or 3 little tarsal claws.
Hunting species in general have 2 claws, whereas all web-building species need 3 claws to hold a grip on the silk strand.
What are tarantula chelicerae?
one of the anterior pair of appendages of an arachnid often specialized as fangs.
The chelicerae of a tarantula completely contain the venom glands and the muscles that surround them, and can cause the venom to be forcefully injected into prey.
Spiders cannot chew on their prey, so they use venom to paralyse the prey and
enzymes to liquify as much as possible outside the spider’s body.
What are pedipalps?
The leg-like features next to the chelicerae, or pincer-like appendages, are the pedipalps.
They are mainly used for probing, digging and feeling.
Internally, the prosoma houses
the central nervous system, venom glands, sucking stomach and muscles for moving the attached appendages.
What is a tarantula opisthosoma?
the posterior bulbus body section is called the abdomen or opisthosoma.
Internally the opisthosoma houses the heart, respiratory organs, the midgut, ovaries and various spinning glands.
Anterior-ventrally on the opisthosoma, on either side of the epigastric region, the “book” lungs are located.
The epigastric region contains an opening, housing the spider’s genitalia.
Near the posterior end of the abdomen spinnerets are situated.
Tarantula lungs are called
book lungs for some reason (their structure is sorta thinly layered like pages in a book)
the first pair is located in a cavity inside the lower front part of the abdomen near where the abdomen connects to the cephalothorax, and the second pair is slightly farther back on the abdomen.
What are spinnerets?
A spinneret is a silk-spinning organ of a spider
Spinnerets are usually on the underside of a spider’s opisthosoma, and are typically segmented. Most spiders have 6 spinnerets.
Describe the nervous and circulatory system of tarantulas.
A spider’s brain is almost entirely found in the prosoma, with only a few ganglia in the opisthosoma.
The shape of the brain reflects the spider’s behavior, as the posterior region of the
brain is bigger in webbers than hunters due to the fact they need a higher sense of
touch to survive.
Tarantulas have an open circulatory system and the arteries carry hemolymph.
Hemolymph contains hemocytes and hemocyanin, a copper-based oxygen
transporter molecule.
Because of the presence of hemocyanin, hemolymph turns blue-green when
oxygenated.
What is The sucking stomach in tarantulas?
The sucking stomach is a widening of the posterior esophagus.
It is located in the prosoma, situated just behind the point where the foregut emerges
from the nervous collar and rests upon the endosternite.
The gut is lined with cuticle up to the sucking stomach, which makes it technically part
of the exoskeleton.
The spider will have to pull the esophagus and the sucking stomach through the brain
during molt.
The sucking stomach is a pump, driven by muscles, to aid the spider sucking the fluids
out of its prey.
Describe tarantula bristles.
Each tarantula has several different types of bristles.
One type of bristle is the setae, which have a hair- or spine-like appearance.
These bristles are sensory organs that allow them to feel vibrations, detect chemicals in the air, and sense the direction of the wind.
The second type of bristles are the scopulae, which are a dense network of bristles at the end of the tarantula’s legs which allow it to stick to surfaces.
One interesting type of bristles belonging to only some species is known as the the
plumose or stridulating bristles, which the tarantula can rub together to make a hissing sound when threatened.
Some tarantulas have urticating bristles which they can detach at will and can be thrown at threats.
