Spineless Critters Trivia Quiz

More precisely, this is a male funnel-web spider, a member of the family Atracidae, which contains 36 species. This little Australian beauty has a reputation for deadliness and a propensity to attack humans which is a bit unfair - only a few species have venom which can seriously harm a human.

The best known of these is the Sydney funnel-web (Atrax robustus), the male of which is probably responsible for most, if not all, of the 13 recorded deaths from a funnel-web bite. It should be noted, however, that none of these have occurred since the development of an effective anti-venine in 1982. Still, parents where they are found (in an area roughly delimited by Newcastle on the coast north of Sydney, Kiama on the south coast, and Lithgow as the furthest extent inland) do well to encourage caution in their children.

(My mother-in-law instilled a terror of all spiders in my daughter, through her constant admonition to "come away from that hole, there might be a spider in it.")

Scorpions, like spiders, are arachnids, with eight legs. Their most characteristic feature is the long segmented tail, which is often carried curled up over their back, with a stinger on the end which they use to inject venom into their prey. The large front pincers are used to grab and hold the prey, which usually consists of insects and spiders, with the occasional small vertebrate (skink, for example).

Scorpions are not a single species; rather, the name applies to a family that contains over 2500 currently-identified species. About 25 of them are capable of killing a human, but this happens relatively frequently, as most of them live in desert areas, where medical support is not great.

Coral is a group of marine invertebrate animals whose bodies are polyps, which are usually found in large groups called colonies. The polyp is usually cylindrical in shape, with an oral end usually surrounded by tentacles. The polyps in any colony are genetically identical, as they reproduce primarily by asexual reproduction (meaning that the offspring inherit all their genes from a single parent). Some species also reproduce sexually, with all the polyps in an area simultaneously releasing gametes which can recombine to create planulae, a mobile form of the polyp which then becomes the start of a new colony when it settles. The members of a colony form an exoskeleton near their attached bases, whose shape is characteristic of their species.

Coral is a fascinating life form whose taxonomic classification has been discussed at length over the years. Only some corals are actually able to catch food (plankton and/or small fish) with their tentacles. Most rely on unicellular organisms that live inside the tissues of the coral (described as zooxanthellae), which produce energy for the coral through photosynthesis. In other words, corals (for the most part) rely on photosynthesis for their energy, which has led some to argue that they should be classified as plants. Others, currently the accepted school of thought, argue that these organisms are separate from the coral despite living inside the coral tissue in a symbiotic relationship, so the coral itself is an animal, being heterotrophic.

Because of their reliance on these zooxanthellae, most corals are found in shallow waters where there is adequate sunlight. This is the case for the well known coral reefs such as Australia's Great Barrier Reef and the Belize Barrier Reef. The zooxanthellae in these corals are responsible for the brilliant colours that characterise the reefs. When the coral polyps are stressed (such as when the water temperature rises), they may expel the zooxanthellae, a process called coral bleaching. This is a sign that the coral is on the verge of death.

Jellyfish are not a single animal, but rather the medusa stage in the life cycle of some Cnidarians, in the subphylum Medusozoa. This just means that they form a medusa (a free-floating form) at maturity, rather than staying as an attached polyp for their entire life (as is the case for corals, for example). Most commonly, the term is applied to members of the Scyphozoa (true jellyfish) class, but Cubozoa (box jellyfish) and Staurozoa (stalked jellyfish) are also included.

The umbrella-shaped bell is made of a gelatinous material known as mesoglea. Its inner surface holds the parts of the jellyfish responsible for nutrition, sensation and reproduction (all distinctly primitive, as there is no central nervous system to coordinate things). Jellyfish range in size from very small (with bells around 1 mm in height and diameter) to very large. The lion's mane jellyfish, often cited as the largest (but with strong competition), has a bell diameter of about a meter, and tentacles that can extend over 35 metres!

Specifically, the image is of Carcinus maenas, the European green crab. Crabs are decapods - their ten limbs consist of eight legs (six for walking, two for swimming) and two pincers, which they use to grasp their prey. They form the infraorder Brachyura, which contains about 7000 species - nearly half the number of species in the entire order Decapodera, which includes lobsters, crayfish, prawns and shrimp.

Crabs typically have a very strong shell encasing the thorax, and rounded body shape due to a dramatically shortened abdomen compared to other decapods - hence the infraorder name, which means short tail. Because of the way their legs are articulated, many of them walk sideways - as reflected in the use of the term crabwise to describe lateral movement.

Like crabs, lobsters are decapod crustaceans, and are found in oceans around the world. True (or clawed) lobsters belong to the family Nephropidae. There are a number of crustaceans with the word lobster in their names (for example, the rock lobster, also called a spiny lobster or langouste), not all closely related to the clawed lobster. Clawed lobsters have claws on three (out of five) of their pairs of legs, with the front two usually being dramatically larger than the others. Their long, muscular tails and these two large claws are the source of most of the meat commonly consumed.

The genus Hommarus contains some of the most commercially significant species of lobsters, including Hommarus gammarus (European lobster) used for the image, as well as Hommarus americanus, the American lobster - often referred to more specifically by the name of the waters where it is found, e.g. Maine lobster.

Nephrops norvegicus, also called Norwegian lobster, langoustine or scampi, is another kind of clawed lobster, although their overall shape resembles a shrimp more than the American or European lobster. The langouste (also known as the rock lobster or spiny lobster), however, is not clawed, and not classed as a true lobster. In the southern hemisphere these crustaceans are often called crayfish, or sea crayfish; don't get confused, they are not the same as the freshwater crayfish which are actually one of the crustaceans most closely related to the lobster.

An ant is a typical insect, meaning they have an exoskeleton that supports their body (which has three distinct parts) to which are attached three pairs of jointed legs. They have compound eyes, and a pair of antennae. All of these are visible in the picture used here, which is of a European fire ant. You can also see the typical narrowing of body segments to form a waist. Unlike many insects, their thorax is fused to part of the abdomen, and this narrow segment, called the petiole, lies between that and the second part of their abdomen, the gaster.

Ants are eusocial, meaning they live in colonies which include a number of individuals (similarly to the closely related wasps and bees). These colonies can be as small as a few dozen, but commonly have thousands (or even millions) of members. The larger colonies tend to be highly structured, and consist of several different types of ants to carry out specific functions. Most of the work (both maintaining the nest and defending it) is done by sterile ants. There is usually a small number of fertile males (drones), and one or more fertile females (queens) in a colony.

Butterflies (along with moths) belong to the order Lepidoptera, a name meaning scaly wing, which describes the way the scales give colour to their four wings. The image selected shows one of the most famous types of butterfly, the monarch (Danaus plexippus). The Monarch's common name is supposed to be in reference to King William III of England, who was also Prince of Orange. Their generic name has its roots in Greek mythology, but sources disagree on exactly which candidate was being referenced as it is not clear.

Butterflies, like all insects, have three body segments (head, thorax and abdomen) and six legs. Each of the three sections of the thorax has a pair of legs, and two of them also have a pair of wings attached. These four wings are what sets them apart. Butterflies are nearly all diurnal (active during the day), which makes their colouration useful; moths, which are nearly all nocturnal, are usually grey or brown, as colour plays little part in concealment at night.

The life cycle of butterflies is familiar to most: eggs hatch to produce a larval stage called a caterpillar; the caterpillar eats its little head off, growing and moulting in a series of stages called instars; when it is full-sized, it forms a pupa (sometimes, but not always, while wrapped in a cocoon spun to provide a protective covering) which undergoes metamorphosis to produce the adult stage, or imago.

Sea stars are commonly called starfish, but they are not fish (a kind of vertebrate) at all, even though they are found in the sea. They belong to a class of echinoderms called asteroidae, Echinoderms, which also include sea urchins, sand dollars and sea cucumbers, have larvae which are bilaterally symmetrical (their bodies can be divided into two halves which are reflections of each other), but as adults have radial symmetry (a central point can have lines drawn to the extreme points of the various segments that form the adult body). They are usually described as having five-pointed symmetry, but starfish do not all have five arms extending from their central disc - some have six or seven, and Labidiaster annulatus (found in the Antarctic) can have over 50! The crown-of-thorns starfish, notorious for its preference for eating coral polyps (and therefore attacking coral reefs) usually has between 15 and 20 arms.

Some species of starfish are found in extremely shallow waters - you can find them in tidal pools, and they are often seen by scuba divers - but others can be found near the ocean floor at almost all depths. Their diet varies with species (and regional availability), but often includes algae, sponges, bivalve molluscs, snails, and other small matter.

Scallop is the common name for a number of species of marine bivalve molluscs in the family Pectinidae. They are one of the few bivalves which are (mostly) free-moving for their entire life cycle, and do not permanently anchor themselves as adults. They move by snapping their shells together, expelling water so as to propel themselves in the other direction. They have a ring of eyes around the outer edge of their mantle (the part of their body that covers the viscera and extends to the edge of, or sometimes protrudes from, their shell).

The image is of Argopecten irradians, the Atlantic bay scallop, whose adductor muscle is commonly eaten - you can see it as a white structure with an orange roe sack. The symmetry of the scallop shell has made it an archetype - if asked to draw a seashell, a scallop shape is one of the first things one is likely to attempt, and it is the logo for a major international petroleum company.

As the name suggests, these annelids (most of which are members of the class Oligochaeta) live in moist soil, where they eat a wide range of organic matter. Their presence assists greatly in the process of making the soil fertile, both in accelerating the process of decomposition to return nutrients to the soil and from aeration due to their tunneling activities.

There are many species of earthworms, with adults ranging in length from 10 mm up to 3 m. The typical Lumbricus terrestris (on the right of the image) is about 35 cm (a bit over a foot) long. These are possibly the most familiar type of earthworm, as they appear on the surface to feed more frequently than many other species, and they have historically been the typical specimens used for educational purposes. Not to mention their use as bait when fishing.

Lumbricus terrestris originated in western Europe, but their presence there has recently been threatened by the presence of two invasive species of flatworms (one from Australia, one from New Zealand) which are highly efficient earthworm predators. This is a matter of some concern for its impact on soil structure near the Atlantic coast.

An octopus is an eight-limbed mollusc (the shell is internal, as is also the case for some other Cephalopods such as the squid and cuttlefish (not a fish). There are about 300 species, including four species of the deadly blue-ringed octopus (one of which, Hapalochlaena maculosa, is shown in the picture). These are one of the smaller species, usually having an arm span between 10 and 20 cm. They are not aggressive, but react to perceived danger - which happens readily, since they live near the shore and in tidal pools, making human interactions frequent, albeit accidental.

The smallest species of octopus is Octopus wolfi (the star-sucker pygmy octopus), with an arm span around 2.5 cm, and a mass under 1 g; the largest is generally given to be Enteroctopus dofleini (the giant Pacific octopus), for which an adult has an average arm span of 4.3 m, and a mass of around 15 kg. Much larger specimens have been claimed.

I have managed until this point to avoid the need to use a plural form of octopus, because opinions on the matter are both divergent and vehement. The most commonly accepted correct plural form in the 21st century is octopuses. Those who are familiar with the classics tend to prefer using a plural that reflects its etymological origin. The Greek -pus (foot) is pluralised as -podes (feet), so a Greek-based plural would be octopodes. This is considered correct but pedantic. In the early 19th century, the plural octopi was favoured, by analogy with a Latin form. However, this would only be accurate if it were a second-declension noun, and octopus is third-declension in its origins. As such, the plural would be octopus.