Wednesday, April 17, 2019

Narlan Valley



Narlan is the name for one of the prominent cities the Vanarans – the main sapient group to colonise the moon – have built on the surface. The term “Narlan” comes from the word for the city in one of the interspecies languages easiest to pronounce for humans (it’s still phonologically distinct from any human language, so transcription into the Latin alphabet is difficult; Dallan and Garrad are also possible spellings). Although the city isn’t particularly large compared to many of the other prominent Nemorosan settlements, it’s one of the oldest, and holds a lot of significance to the Nemorosan Vanarans.

The general region surrounding the city is also known as Narlan. Due to their level of technological development, very little farmland is needed, since much food can be produced indoors in molecular synthesisers. The base materials for these foods comes from simple but fast growing plants which can also be grown within the city. Because of this, the surrounding countryside is able to grow wild and is relatively unaffected by the activity of the Vanarans.

The area is filled with large black trees, relatively spaced out from each other due to the lack of sunlight reaching lower ground. This prevents very many new plants from growing. Instead, most of the forest floor is covered in sessile non-photosynthesising organisms, many of which are primary producers obtaining their energy from chemosynthesis. There are many secondary producers too, feeding off of dead matter that falls to the dim forest floor.

Most of the ground these plant-like organisms grow in is composed of ice – both water and ammonia – but there are also a great deal of organic compounds in the soil, hydrocarbons larger than methane that remain solid at the moon’s temperature range. Many of these, of course, would be liquid or gaseous at room temperature.

The forest is located in a valley, with extremely large slopes on either side. Because of the planet’s low gravity, the relatively low density of ice compared to rock, and the much faster nature of geology on ice worlds like Nemoros, the moon can have much more dramatic topography. Floods can often be quite severe, though luckily the weather progresses much more slowly so there’s usually plenty of warning, with any “animals” that need to slowly retreating to high ground. These floods provide plenty of nutrients for life on the forest floor, especially for the chemosynthesisers. This makes them an important part of the forest’s ecology, ensuring the sulphurous compounds in the ice soil are constantly replenished.

Narlan is quite close to the moon’s equator, although with such a dense atmosphere distributing the temperature this has little effect on the climate. Narlan is also on the side of the moon facing Aulea, which – although completely obscured to any human standing on the surface by the smoggy tholin layer – is visible high in the sky to the Vanarans, who can see infrared.



Tree
(Macrophyllales)



Size: Varies, often grows up to 200 metres, with the tallest species reaching a kilometre.

Habitat: Terrestrial; specific preferred conditions depend on species 

Colouration: Black

Symmetry: Radial

Reproduction: sexual, both fertilization and the distribution of spores occurs by wind and methane dispersal in most tree lineages


Most large trees on Nemoros belong to a phylum of plant-like organisms that grow in a repeating segmented fashion, forming tall chains of these segments. In most species, each segment possesses a small hydrogen sac in the centre, and in the larger and more tree-like lineages there’s a large bladder at the top of the plant. These tree-like lineages also possess around two to five very large leaves at the very top. With the low light levels, light competition is high, so leaves need to be very large to get enough sunlight. Although these plants are black, absorbing most light in the visible spectrum, they absorb infrared light even more strongly, which is what they obtain most of their energy for photosynthesis from. They also engage in a degree of chemosynthesis.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Atralia
Division: Segmentophyta
Class: Dendrophyceae
Order: Macrophylales



Fungal grass(Muscomycetes)


Size: A few millimetres to many centimetres in length, diameter is much smaller

Habitat: Terrestrial, grows best in wooded areas with low light where it doesn’t run into competition with photosynthesising organisms

Colouration: White or grey, sometimes brown

Symmetry: An individual “blade” (or hair) has roughly circular symmetry

Reproduction: sexually or asexually, via the spread of spores. Specific reproductive strategies vary by species.

A hair-like chemoautrophic organism grows near the ground, somewhat fungus-like in appearance. It can be grey or white in colour, and there are also larger bushes formed of distantly related species. This is what most grazing animals on the surface eat in wooded areas, and in fact many browsing animals eat from the fungal bushes. With little light reaching the ground, chemosynthesis is more practical on the forest floor than the photosynthesis large trees engage in. As well as chemosynthesis, these fungus-like organisms are able to absorb dead rotting biomatter, recycling dead trees and “animals”.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Aphota
Division: Pilosomycota
Class: Muscomycetes

Tachyptilon selenopolis




Size: 30 cm up to neck

Diet: vegetation and “fungus”

Habitat: Woodland river valleys

Colouration: Orange with darker blotches

Symmetry: Triradial

Reproduction: Fuses with mates as larvae, growing into a chimera


This small herbivore spends a lot of its time hiding in fibrous “fungal” bushes from predators like Crytodus and other otodons. Their hairy bodies allow them to feel around in these bushes without having to use their sonar, which will alert their presence to predators.

There are multiple Tachyptilon species in the Narlan forests, each focusing on a slightly different diet to avoid competition. The largest, Tachyptilon selenopolis, is able to use its long neck to reach vegetation from small trees or tree-like “fungus”, often absorbing nutrients directly into their gastric feathers, which are almost permanently out and able to stretch in size.

While their primary head is used to obtain food from above them, food from the ground is eaten with the mouths under their feet. They have well developed digestive systems on all four limbs, unlike most other trilaterians in which the leg stomachs are very reduced. Their feet being adapted in this way allows them to eat from the ground without having to bend their heads down.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Myostea
Order: Peinopoda
Family: Tachyptilidae
Genus: Tachyptilon
Species: Tachyptilon selenopolis


Giant Striped Acanthid(Eurygaster gulastomachus)



Size: 3 meters tall

Diet: Aphotans (grassy fungus-like organisms) and other sedentary primary producers. They are also detrivores, eating any dead organic matter that falls from the countless aerial organisms above.

Habitat: Can be found in a wide range of habitats, primarily open woodland and savannas

Colouration: Dark grey or orange with dark stripes

Symmetry: Triradial

Reproduction: Fuses with mates as larvae, growing into a chimera


While the most primitive trilaterians have their “heads” and the top of their body, more closely resembling the tetrahedral shape of their ancestors, this isn’t a very convenient position for grazing from the ground. Because of this, there is a particular lineage – hypostomes – who have essentially flipped upside down, with their primary mouths facing the ground. Without the need to browse for food in trees or bushes, having this appendage at the top of their body serves little advantage to outweigh the costs.

The hypostomes of the Narlan woodland have a diet that consists mostly of the fibrous fungus-like chemosynthesisers that grow in the flood basin, as well as dead biomatter that falls from aerial life forms. The sulphurous compounds these fungi organisms need to grow are renewed during the regular flooding, which means these floods are an important part of the ecology for the animals that eat the fungus. Although many species of this fungus have adapted to this grazing by becoming tougher, Eurygaster has a claw-like beak on its primary mouth which allows it to bite through the tough tissue with ease, and a digestive system well adapted for processing it. All the way down its throat are rows of blunt teeth for grinding down its food.

Like many other “herbivorous” trilaterians, this animal is able to obtain nutrients not only from their primary mouth, but absorbs it through their feet too. It is especially common for liquid methane to be absorbed this way, particularly during flooding when the bottom of their feet are often submerged anyway.

Eurygaster tends to gather in large herds for protection against predators. There is often a complex social structure, although they’re peaceful and fights for dominance within a group are uncommon. Usually, the oldest and largest member of a group will lead and decide where to graze next. Each of their three legs possesses a large pouch for sound production, with the air expelled through slits below it. The sounds produced by these pouches are used for communication between members of the herd. Their pouches are also an important part of their echolocation, allowing them to detect approaching predators from great distances away, much better than eyeless species without these pouches can. If they sense approaching danger, they gather closely together to make themselves more intimidating to predators, who are usually much smaller than they are.

These animals find it hardest to defend themselves against aerial predators like Opticophis, since   their usual tactics of gathering together don’t work as well against predators that can attack from above, targeting the weakest members of the group without having to go through the others. Aerial predators can also easily retreat if it’s too much for them to handle, so the risks around attacking are relatively low. These two factors mean large groups aren’t as much of a deterrence as they are with ground based predators. To counter this, the back of Eurygaster is covered in large, sharp spines, which make attacks from above more difficult. Usually, if a flying predator wants to attack the animal, they will have to fly lower and strike its unprotected sides, which puts the predator in greater danger of being attacked by the individual and other members of its herd.  

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Myostea
Order: Hypostomata
Family: Acanthidae
Genus: Eurygaster
Species: Eurygaster gulastomachus




Narlan Acanthodon(Acanthodon aequatorensis narlanensis)




Size: 1.4 meters up to neck

Diet: Carnivorous, primarily focuses on large hypostomes

Habitat: Tropical forests, grasslands and savannahs (the subspecies A. a. narlanensis is adapted to rainforest wetlands)

Colouration: Pale grey

Symmetry: Triradial

Reproduction: Fuses with mates as larvae. As chimeric adults, they find a mate to fuse their larvae with. They are also able to reproduce without a mate, producing identical chimeras. Their tiny larvae are released into the air after fusing, although they do still take care of their young; the entire group raises any Acanthodon young that grow in their territory communally. Acanthodon larvae don’t travel far, so they are usually related to pack members.


Although the horn-like structures at the ends of each limb are used for hearing in most tetrastomes, there’s a particular lineage of trilaterians where these hearing organs have adapted for use in catching prey. Called otodons, these creatures have three tooth like structures at the end of their primary mouth, whereas in the limbs used as legs they have retained their ancestral function. It’s a particularly large group, most members of which are carnivorous, and species within this group use various different hunting strategies.

Acanthodon is a particularly social otodon, living in large groups and hunting prey larger than itself in packs. They are quite intelligent, capable of a great degree of cooperation and planning, and have a complex hierarchal group structure. Acanthodon can be violent to individuals from outside the group, and will attack if any are trespassing on their territory.

They have three large stomach feathers permanently on the outside of their body, which gives them a well-developed sense of smell they use for tracking prey. The aural horns on their pedal mouths are quite well developed, allowing them to hear prey nearby or detect them with sonar. To mark the territory of the group, they chemically mark the ground they walk on with a substance excreted from the mouths of their feet. This chemical signature can be detected by gastric feathers under their feet, and they are quite familiar with the signature of other members of their group.

Able to take down prey larger than itself by relying on numbers, Acanthodon focuses primarily on hypostomes and other large creatures. However, they are rarely ever able to kill the much larger hadrosomes because of their colossal size, so they are relatively safe from Acanthodon.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Myostea
Order: Otodontes
Family: Acanthodontidae
Genus: Acanthodon
Species: Acanthodon aequatorensis
Subspecies: Acanthodon aequatorensis narlanensis


Curve Toothed Otodon(Cyrtodus stigmatos)



Size: 60 cm up to neck

Diet: Meat, eats small animals

Habitat: woodland

Colouration: Orange to grey with darker splotches

Symmetry: Triradial

Reproduction: Fuses with mates as larvae. As chimeric adults, they find a mate to fuse their larvae with. They are also able to reproduce without a mate, producing identical chimeras. After fusing, as much of their larvae as possible is planted into a specific part of the ice, which the parent guards.

Not all otodons are large apex predators like Acanthodon. Cyrtodus goes after much smaller prey, and are solitary hunters, preferring stealth and ambush to hunting prey down. They often sit in fungus bushes, waiting for suitable prey to pass, then grab them, making use of their long, swift necks.

In order to better hide themselves, they don’t use active sonar to detect them, since the sound would alert their prey to their presence. Instead, they listen for the sound of their footsteps. Their senses are keen enough that they can draw a clear picture of their surroundings just from this. However, this also means it’s possible to avoid them by staying very still, making as little noise as possible, although luckily for Cyrtodus  this only works if every other animal nearby is quiet too.

These carnivores also have predators of their own. Since they’re a common target of Opticophis, they have well camouflaged bodies, increasing their chances of escaping the notice of their eyed predators. The dark blotches and patches that break up their form don’t only conceal them from predators; many of the small airfish they catch possess eyes, too, so it serves them well to remain camouflaged from them. 

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Myostea
Order: Otodontes
Family: Belonodontidae
Genus: Cyrtodus
Species: Cyrtodus stigmatos




Narlan Onychotid
(Belonoglossa maximus)



Size: 1.8 metres from ground to neck when standing

Diet: Vegetation from trees

Habitat: Arboreal

Colouration: Dark grey to black

Symmetry: Triradial

Reproduction: Fuses with mates as larvae, growing into a chimera


Living high in the trees, Belonoglossa is relatively safe from non-aerial predators. Their aural horns have adapted for use in climbing, growing longer in size to allow these creatures to hang from them. They spend most of their time eating, absorbing nutrients from the tree’s fluids by planting their sharp-tipped prehensile tongue into it. Sensory feathers on this tongue allows the creature to feel around for the most nutrient rich areas, or find any other food worth eating such as the mossy fungus that often grows on trees.

High up in the tree canopy, Belonoglossa has access to more sunlight than most terrestrial species in the area, and since it’s relatively inactive it’s able to spend a great deal of its time photosynthesising. Because of this, its skin is very dark, pigmented by the high amounts of melanophyll present.
Belonoglossa is still at risk of being preyed on by Opticophis and similar occulates, and since they’re relatively poor at defending themselves they have developed a poison to deter predators.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Myostea
Order: Macroglossida
Family: Onychotidae
Genus: Belonoglossa
Species: Belonoglossa maximus



Macroglossa pinguis



Size: 1.4 meters up to neck

Diet: omnivorous. They eat small animals, especially airfish, as well as “plant” matter and “fungus”

Habitat: forests

Colouration: white or pale grey with blotches of dark grey, black or brown

Symmetry: triradial

Reproduction: Fuses with mates as larvae, growing into a chimera


Macroglossa belongs to a lineage of large tongued tetrastomes, most of which are omnivorous. The tongue developed from an extension of the flesh on the inside of the mouth, and is able to stretch far beyond its resting size. Macroglossa can use this to obtain food. Small animals are also caught with this tongue, and it possess three sensory feathers sensitive to not only touch but also taste and smell.
Like Cyrtodus, they are primarily solitary hunters, and focus on ambushing small prey. Their well camouflaged body allows them to remain hidden from eyed airfish, which they can often be seen lashing at with their tongues.

In order to effectively digest their varied diet, they have a very well developed digestive system, with a large chemical stomach to effectively break down food. Their feather stomach, however, is of a typical size, although it’s able to absorb both “plant” and “animal” matter.

Macroglossa is able to climb trees, using its feet mouths as suction cups, reducing air pressure by expanding the sonar sacs. This allows it to reach vegetation it otherwise wouldn’t be able to.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Myostea
Order: Macroglossida
Family: Macroglossidae
Genus: Macroglossa
Species: Macroglossa pinguis



Uranoichthys macrourus





Size: 3 meters long

Diet: Tree vegetation, tree “fungus”

Habitat: The air, usually near trees

Colouration: Black on top, white underneath

Symmetry: Bilateral

Reproduction: Fuses with mates as larvae, growing into a chimera


These large, fish-like creatures swim not in a liquid, but in the air. With the moon’s extremely thick atmosphere, flying is more like swimming, with the air about a tenth as dense as water, or a fifth as dense as liquid methane. It takes little hydrogen to keep aerial species buoyant, which is stored in their swim bladders, and some smaller airfish are able to stay in the air through the act of swimming alone.

Uranoichthys macrourus is a particularly large species of airfish – although airfish can get much bigger – though even at its size it has no trouble staying afloat. Unlike most trilaterians, not one but three of their limbs are used as primary mouths, with the third functioning as a tail. They also lack the ancestral triradial symmetry of trilaterians. The three mouths allow it to obtain more food than would otherwise be possible; if it had just one, eating the same amount of food would be more time consuming. This is especially important for providing an “animal” of its size with the energy needed for flight, as well as the energy needed produce enough hydrogen to remain afloat.

Uranoichthys has extremely large sonar sacs, as well as slits on its tail for the passage of air, similar to Eurygaster. This not only allows it to detect predators more easily, but gives it the “visual” acuity needed to fly affectively. This is especially important in a forested environment, with a lot of obstacles to navigate through.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Tricephalida
Order: Megalocystes
Family: Megalocystidae
Genus: Uranoichthys
Species: Uranoichthys macrourus


Carnivorous Oculate
(Opticophis narlanensis)



Size: 1.5 - 2 meters long

Diet: meat; tends to focus on large myosteans like acanthids, but will eat a large variety of prey

Habitat: woodland

Colouration: grey

Symmetry: Bilateral

Reproduction: Fuses with mates as larvae, growing into a chimera


Not all tetrastomes navigate entirely through sonar. One lineage, called Oculata, have developed a row of eyes at either side of the body, developed from photosensitive strips their ancestors used to detect orientation and the time of day. Most oculates are carnivorous, making full use of the advantage their eyesight gives them over most prey species.

Like many oculates, Opticophis is an ambush predator, able to silently spot any prey with its eyes. The frontmost pair are the most developed, and are situated at the end of extendable stalks that allow them to look around more easily. Common to other oculates their three mouths also have beaks, which have a strong bite able to cut through the flesh of most prey and even shells.

They are comfortable swimming both ways up, and will usually orient themselves in the position that allows them to spot their prey the clearest, without their fins obscuring their eyes.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Tricephalida
Order: Oculata
Family: Caulopsidae
Genus: Opticophis
Species: Opticophis narlanensis



Airfish
(Triallorhampus brachylaemus)



Size: 20 - 30 cm long

Diet: tiny insect-like organisms, seeds

Habitat: In the air in forests, as well as lakes, rivers, and ponds

Colouration: grey or grey-brown

Symmetry: bilateral

Reproduction: Fuses with mates as larvae, growing into a chimera


As well as the much larger species, there are countless small, fish-sized airfish that can be seen swimming in the air. Distantly related to Uranoichthys, Triallorhampus possess a broad tail fluke, and has thin, long mouths that allow it to effectively eat seeds and catch insect-like organisms. They have two thin dark photosensitive strips on either side of their back, which Vanaran genetic studies have demonstrated to be homologous with Opticophis eyes. This is likely an ancestral feature retained from the common ancestor of the two groups.

Triallorphampus is comfortable both in and out of methane. When it wants to enter a body of liquid, it increases the pressure of its swim bladder to reduce buoyancy.

This is only one of the many small airfish species present in Narlan. There are countless others, too many to give a comprehensive description of here.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Tricephalida
Order: Megalocystes
Family: Pterygourida
Genus: Triallorhampus
Species: Triallorhampus brachylaemus



Decaophthalmos borealis


Size: 10 - 20 cm long

Diet: fruit and seeds, fungus, vegetation

Habitat: In the air in forests, in forest lakes and rivers

Colouration: brown or grey-brown, often has a blotted patterning

Symmetry: bilateral

Reproduction: Fuses with mates as larvae, growing into a chimera

Not all small airfish are eyeless. Decaophthalmos is distantly related to Opticophis, with five eyes at each side of their body. Their diet is more herbivorous than that of Opticophis, consisting largely of hard fruit and seeds, which it can crack open with its strong beaks. While most of their relatives use their eyes to see prey, as a herbivore Decaophthalmos uses its vision spot predators and search for food. Their vision provides them an edge over many other species when it comes to avoiding predation, as it allows them to see predators from much further away; sonar only works to a limited distance.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Tricephalida
Order: Oculata
Family: Bicaudidae
Genus: Decaophthalmos
Species: Decaophthalmos borealis



Wetland Gigantid
(Diphyllops potamodytes)


Size: 30 meters at shoulder

Diet: tree tissue, aphotan “fungus grass”, tree “fungus”, “fungus bushes”, shrubs, ice

Habitat: Wetlands, often forested wetlands

Colouration: grey skin, white exoskeleton

Symmetry: Bilateral

Reproduction: Adults search for a mate for their offspring to merge and become a chimera with, and let the larvae grow in a nest. These larvae are looked after until they’re developed enough to take care of themselves.


While the majority of tetrastomes lack a hard skeleton, hardly needing it in the moon’s low gravity, this isn’t true for all lineages. In particular, one group, the hadrosomes, possess an exoskeleton, providing them with much greater support for their often immense size.

According to Vanaran genetic studies (fossils are hard to obtain or date in the shifting ice), the first hadrosomes possessed a full covering, initially protecting them from moisture loss and defending them from predators. Later on, however, their skeletons opened up, greatly reducing their weight while still providing a degree of support. Some fully covered species exist today, mostly in dry environments.

As one of the few lineages with skeletons, hadrosomes are able to grow far larger than any other group, reaching gargantuan proportions.  With the moon’s low gravity, they can easily grow larger than any animal on Earth. Tetrastomes usually breathe through their skin, which works well in the thick air, but at the sizes hadrostomes reach this isn’t efficient enough. Instead, hadrosomes possess lungs, developed from modified swim bladders. A hole on either side of the body, going through the pelvic bone, leads to this lung.

Although they are trilaterians, they have moved away from the basic three-fold symmetry of the group, with the rear limb functioning as a tail to counterbalance its head in most species.

With its long neck, Diphyllops and other gigantids are able to reach for food without having to move their large, lumbering bodies too much. A small long-necked head is essential for such a large animal, which will inevitably require large quantities of food.

On the sides of their neck are two overgrown external gastric feathers. These serve a primarily sensory function, although for the purpose of efficiency they do absorb nutrients as they feel around. These feathers are sensitive to both touch and taste, which are this creature’s primary senses. The feathers can extend to tens of times their resting size, so Diphyllops can effectively make itself aware of its surroundings within a large radius this way without having to move. As it feels around with these feathers, it is primarily concerned with searching for food.

Diphyllops potamodytes, adapted to a forested environment, is smaller than many other gigantid species. It is also able to absorb nutrients through its legs and tail, with well-developed stomachs in those parts of its body. This is to make use of the frequent floodings, and the nutrients that come with it. When the ground is wet, or rich in nutrients from a recent flood, these nutrients are absorbed through the feet.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Hadrosomata
Subclass: Psilodermata
Order: Platyurida
Family: Gigantidae
Tribe: Diphyllopini
Genus: Diphyllops
Species: Diphyllops potamodytes



Swamp Otocerus(Otocerus paluster)


Size: 15 metres at shoulder

Diet: aphotan “fungus grass”, shrubs, ice

Habitat: Wetlands

Colouration: grey skin, white exoskeleton

Symmetry: Bilateral

Reproduction: Adults search for a mate for their offspring to merge and become a chimera with, and let the larvae grow in a nest. These larvae are looked after until they’re developed enough to take care of themselves.


Otocerus is another hadrosome, belonging to a family closely related to Diphyllops. As platyuarids, both groups use their tail as an extra base of support, resting on it when they need to, with a flat pad at the tip to support this function. This allows them to support more weight than most otherwise bipedal hadrosomes.

Otocerus, rather than growing a long body with an extended neck, instead makes use of this greater support by growing outwards, with a stocky body and thick musculature. Their neck is much shorter than that of Diphyllops, but much thicker, making it better protected during the frequent fights for dominance these animals engage in. The heads of all its relatives is covered in a thick, strong skull, which is used for head butting. Some, including Otocerus, also have tusk like horns coming out of their necks, which are actually modified hearing organs.

Otocerus often rests on its head, giving its heavy body four points of support. It supports its weight on its tusks, which are strong enough to do this, usually lifting it back up to move. However, sometimes they will drag their tusks against the ground, especially if the ground is particularly muddy and with low friction, leaving distinctive tracks. They have a large stomach in their necks, which brings their centre of gravity forwards; this is why resting their head against the ground is so important. If they don’t do this, they have to bring their legs further forwards towards their centre of balance, increasing torque on their leg muscles.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Superclass: Trilateria
Class: Hadrosomata
Subclass: Psilodermata
Order: Platyurida
Family: Osteopidae
Genus: Otocerus
Species: Otocerus paluster


Trachyderma magnus


Size: 1.5 metres in diameter

Diet: Vegetation, largely aphotan “fungus” growing on trees

Habitat: Forests

Colouration: Grey

Symmetry: Four fold spherical symmetry (tetrahedral)

Reproduction: Fuses with mates as larvae, growing into a chimera


Although trilaterians are highly successful, not all tetrastomes belong to this group, with some retaining their ancestral features. Trachyderma is particularly primitive compared to trilaterians, with the tetrahedral symmetry found in the first tetrastomes – although unlike the first members of this group, who were aquatic, Trachyderma lives out in the dry air. Although spherical symmetry would normally be more of a disadvantage outside of the moon’s murky lakes and seas, Trachyderma magnus is nevertheless a common sight outside Narlan City, often seen floating through the air.

These creatures move primarily using jet propulsion, releasing dense air from their sonar sacs to provide thrust. There is a slit on each limb leading into the sonar sacs, allowing air to be continually pumped into the sacks and out of the mouth during flight. With a hydrogen filled swim bladder, they were able to remain buoyant in air, although their jet propulsion produces enough force that they should remain airborne even without it, especially smaller individuals. This is due to the low gravity, which means it takes less energy to stay in flight in general, coupled with the dense atmosphere, allowing a given volume of air expelled to produce more thrust than it would on earth.

Since they have legs facing in every direction, it’s possible for them to move around entirely though jet propulsion, without bending their limbs at all. In fact, some similar species are unable to move their limbs, with their rigid skin not allowing for this. Trachyderma, however, is capable of such movement, with the ability to change the rigidity of its skin through chemical processes in its body. When its skin is harder, it is much better protected from predators, but at the cost of flexibility, so this is usually its resting state. When it needs to change position, or when feeding, it will make its skin become more pliant before bringing it back to its harder state.

To further protect it from predators, Trachyderma has a body covered in small spines, making it more unpleasant to eat. This protects it even from animals large enough to eat it whole, who find consuming these creatures unpleasant.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Superphylum: Megaptila
Phylum: Tetrastomata
Class: Acamptopoda
Order: Podotremata
Family: Acanthoasteridae
Genus: Trachyderma
Species: Trachyderma magnus



Ditreme(Sedecopes virosus)



Size: 10 – 15 centimetres long

Diet: vegetation, much smaller “bugs”

Habitat: Trees

Colouration: Orange or red, also reflects light in the infrared

Symmetry: Bilateral

Reproduction: grows flowers on body, which produce tiny larvae. Larvae merge with a mate, then grow in a pouch inside the mother’s body


Although the majority of large, motile land organisms are tetrastomes, other phyla do exist on the moon. Ditremes are one such example. Most are tiny, comparable to insects and worms on Earth, although some groups are larger, especially on the sea floor.

Unlike tetrastomes, which have an incomplete digestive system with only a single opening acting as both a mouth and an anus, ditremes have a digestive tract running entirely from one end of their body to the other. They tend to have elongated bodies, with more primitive members of the group being worm-like, and have skin that’s able to contract which allows their entire body to act as a muscular hydrostatic skeleton. This contractile tissue functions similarly to the muscles of Earth life (although due to the low temperatures it must be chemically very different to function), unlike the coil muscles of tetrastomes, suggesting they have an independent origin to tetrastome muscles. They lack hearts of any kind, with transport fluids either drifting naturally or being forced to move from the movement of the organism itself.

Sedecopes virosus is one of the largest species in the Narlan forest. It’s a very advanced ditreme, possessing both legs and eyes, with the front most pair of legs adapted for food consumption, with a serrated inner edge. The pair second to the front bear the organism’s photoreceptors, primarily sensitive to infrared, which is what most of the light reaching the surface of the moon consists of.

In order to avoid predation they have developed a toxic substance inside their body fluids, deterring predators. In order to both alert their presence to predators and to herbivores that may eat them accidentally, Sedecopes has a number of adaptations that allow them to stand out more. To warn visual animals, they are brightly coloured and have a series of stripes running along their back. While they stand out even in the visual spectrum, in the infrared can be distinguished from their surroundings even more so. However, this doesn’t work for animals with no eyes, of which there are many, so a second adaptation is the presence of specific textures on their stripes which echolocateing organisms should be able to detect with their sonar. Animals learn to recognise these patterns, and avoid them.

Although most ditremes do lack skeletons of any kind, Sedecopes has a long flexible cord running along the outside of its back, providing support not otherwise provided by the hydrostatic skeleton. This feature is shared by all rhabdonotes; organisms belonging to a specific order of ditremes. Other than this, however, Sedecopes is boneless, supported entirely by hydrostatic pressure.

Selection of various other ditremes
Although small brained, Sedecopes engages in quite complex social behaviour. They establish groups and large territories, and will often fight any intruders they feel threatened by. To mark their territory, they leave their urine everywhere, possessing specific chemicals they can be identified by. They use the two appendages near the back of their body to spread this urine around, which are also able to secrete specific pheromones. The pheromones from these limbs can be used to convey specific messages.

Pheromones and urine embedded on the surface of trees is detected with chemical receptors on the sensory hairs of their limbs, especially those of the eyes and rear limbs.

While many ditremes simply release their larvae into the air and hope they find other larvae to merge with, Sedecopes specifically seeks out a mate. Complex mating dances and pheromone tastings are done, until they eventually find suitable partners, based on indicators of health. Mating rituals usually take place during the 37 hour long nights, when it’s dark enough to escape the notice of the few oculate species immune to their poison. The climate is hardly affected by season, but in order to ensure individuals’ reproductive cycles line up, flowering usually occurs during their mating season in the sun is directly overhead, which occurs twice a year.

Unlike tetrastomes, their flowers tend to be relatively small, fewer in number, and less random in arrangement. Usually a pair of small extensions grow near the head, which are capable of movement and able to extract or deposit larvae between individuals. While they’re stiff in most ditremes, Sedecopes has developed such that during flowering the muscular wall of the outer body extends and begins to grow around the flower, allowing the flower to act as a muscular hydrostat capable of movement.

Once larvae are ready, the Sedecopes mother consumes them and allows them to grow inside a pouch in their body. They exit through the mouth once they are large enough, and the mother takes care of them. Usually they have much fewer offspring at a time than other ditremes and even tetrastomes, focusing on the survival of a few rather than having as many as possible.

Taxonomy
Tree: Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Phylum: Ditremata
Class: Micropoda
Subclass: Videacia
Order: Rhabdonota 
Family: Campidae 
Genus:  Sedecopes 
Species: Sedecopes virosus



Lepidozoan
(Longipes acanthophyllon)


Size: 30 centimetre diameter with limbs spayed out

Diet: Vegetation

Habitat: Forests, in the air

Colouration: brown exoskeleton, black leaf

Symmetry: Radial (six fold)

Reproduction: reproduces sexually, all are hermaphroditic, lays eggs



Another common phylum is Lepidozoa. Like ditremes, they tend to be relatively small, although they are far less widespread or diverse compared to ditremes. However, they have an advantage over ditremes, which is the present of an exoskeleton, protecting them from moisture loss.

Both tetrastomes and ditremes can be compared to Earth slugs, unable to thrive in dry environments, although they are somewhat better protected from moisture loss than slugs are. Lepidozoans, however, are abundant in arid climates.

While a fully covering exoskeleton would be a disadvantage to most of the photosynthesising organisms of Nemoros, these organisms possess a leaf-like structure growing out of their backs exposed to the open air, where most of their photosynthesis takes place. Although they’re unprotected, they can be regenerated relatively easily.

Lepidozoans are more distantly related to tetrastomes than ditremes, laying eggs and mating through the exchange of gametes rather than fusing as larvae. They also have permanent reproductive systems, instead of flowering. While ditremes and tetrastomes could have developed these similar mating strategies independently, genetic studies performed by Vanarans confirm that these are homologous traits.

Longipes belongs to one of the few aerial groups of lepidozoans, with an internal hydrogen bladder much like those of many tetrastomes keeping it afloat; although due to their small size not all members of this group possess them. Their six long legs allow them to feel around well in the their forested environment without the help of eyes or sonar, and the hairy ends of these limbs can act as fins to guide their movement, as well as serving their sensory function.

Taxonomy
Tree:  Nemorosavitae
Domain: Chemoplastae
Kingdom: Mobilida
Phylum: Lepidozoa
Superclass: Podocyclida
Class: Celypheopoda
Order: Aerocelyphea
Family: Hexapterygidae
Genus: Longipes
Species: Longipes acanthophyllon



Lecanra (Nemorosan garden star)
(Lecanra omnivora)


Size:  Usually 20 – 40 centimetres in diameter

Diet: Specific aphotan “fungi” that grows on trees

Habitat: Various; the subspecies L. omnivora nemorosensis in particular is particularly well adapted to living on trees and other sessile organisms.

Colouration: pale pink

Symmetry: Four fold radial symmetry

Reproduction: sexual or asexual, all hermaphrodites, lays eggs. Young are bilaterally symmetrical, similar in appearance to a single adult segment; other segments grow as the larva matures.

Not every organism on Nemoros is native to the moon. With the colonisation of the body a few centuries ago by the Vanarans, there are a number of introduced species, whether intentional or not. Already, the moon is teeming with single celled organisms from the Vanaran home world Vanarek, which was something that was very difficult to avoid. There are also a few larger species, including Lacanra omnivora, now a common sight in the forests surrounding the city of Narlan as well as many other parts of the moon.

They were once a common garden pest on Vanarek, very adaptable and able to eat a wide range of plants, although nowadays with most hobbyists gardening in an enclosed environment this isn’t as much of an issue (although sometimes they are deliberately placed into gardens to simulate the difficulty of avoiding pests). This is what gave them their name, translating very approximately as “garden starfish” in most Vanaran languages; Lecanra is this name’s translation in the vocal trade language, with a more or less similar etymology. In the past they could commonly be found in houses, too, and owing to their versatility some have found their way aboard space ships.

They were adaptable enough that they were able to survive after arriving on Nemoros. Their diet on the moon is very limited, however, since, because of differences in the chemistry of Nemorosan life, there is a lot of tissue they aren’t able to process. Still, they are able to live off certain fibrous fungi growing on trees, and this is more a blessing than anything else since it means they don’t outcompete native species and drive them to extinction. With a very specific niche, other organisms are able to focus on foods Lecanra doesn’t eat.

Their basic body plan has tetraradial symmetry, with four long limbs with mouths close to the end. This makes them somewhat resemble a four armed starfish. Food travels through a long digestive tract in each limb, exiting through an anus at the centre of the body. There is a single eye at the end of each limb, sensitive to infrared light. Hairs projecting from the end helps it find food, sensitive to taste.

Each limb has a series of spines at either end; these spines function similarly to legs, grasping the substrate as the animal moves. As the animal stretches forwards, it grasps the tree or ground with these claws, pulling itself across. The two frontmost claws are perhaps the most important, piercing the substrate, although the claws second to the front assist in turning. The claws are unable to bend, except slightly where they join the body (although the second-to-front claws are more flexible) only serving as a means of clinging to the surface either when staying still on a tree or moving across it like an inch worm.  

Since Vanarek is far drier than Nemoros, Lecanra has a layer of scales to protect it from moisture loss. Since this prevents the animal from breathing from its skin, it has eight spiracles on its back leading to a system of trachea where hydrogen is absorbed.

Taxonomy
Tree: Vanaravitae
Domain: Panethana
Kingdom: Xenoteichea
Phylum: Actinoura
Class: Squamatostellida
Order: Quadrilateria
Family: Lecanridae
Genus: Lecanra
Species: Lecanra omnivora
Subspecies: Lecanra omnivora nemorosensis



Tuesday, January 22, 2019

Tetrastomes

Multicellular life on Nemoros doesn't easily fit into the three kingdoms of Earth life. Many mobile organisms - those belonging to the kingdom Mobilida specifically - still engage in chemosynthesis and often even photosynthesis, possessing the "chemoplasts" of more plant-like organisms. The chemoplasts are likely to have evolved as a result of a symbiotic relationship with microsomes, organisms belonging to a domain of single celled chemosynthesisers. These chemoplasts can also engage in hydrogen respiration, so are essential for supporting the active lifestyle of mobilids. These animal-like organisms actually have far more chemoplasts than "plants" do, although they are often lower in melanophyll (the main photosynthetic pigment on Nemoros), instead being more specialised towards their role in respiration. 

A typical tetrastome

Most large mobilids belong to the group Tetrastomata. Tetrastomes are characterised, at least basally, by tetrahedral symmetry, four long limbs, the presence of mouths at the end of each limb, and feather-like filaments used in digestion.  

Spherical or near spherical symmetry is quite common in the seas of Nemoros; the heavy plant life prevents fast movement, so for most floating organisms there is little evolutionary pressure for a differentiated top or bottom, or front and back. For most bilateral organisms, gravity provides the up-down distinction, whereas the direction of movement provides the front-back distinction; pressures that aren't nearly as strong in the oceans of Nemoros. 


Circulatory and respiratory system


Like most  Nemorosan "animals", tetrastomes engage in hydrogen respiration. They obtain hydrocarbons from other organisms, eaten with their four mouths, from which energy is obtained through reactions with atmospheric hydrogen taken into the body. Unsaturated hydrocarbons with double or triple bonds are where most energy is obtained through this process, especially acetylene which many plants use for energy storage. Nemorosan respiration produces methane as a byproduct, which replenishes the methane absorbed by plants during photosynthesis and chemoautotrophy.

Tetrastomes have methane filled tubes throughout their bodies used for the transport of nutrients and gasses. There are numerous pumps in the middle of their body used to drive the movement of this circulatory system. Their circulatory fluids contain no hydrogen carrying substance, so they're only able to carry whatever hydrogen will dissolve directly into the methane. 

Tetrastome internal anatomy. Each limb shows a different organ system;
in reality, all organs are present in all limbs
The vast majority of tetrastomes lack lungs, instead exchanging respiratory gasses through the skin. This is inefficient, but given the dense atmosphere and the relative unenergetic nature of most tetrastomes this poses few issues.

Digestive system


Unlike the vertebrates of Earth, tetrastomes don't have a complete digestive tract. Instead of beginning at one end of the body end exiting through the other, once food is digested it comes back up the digestive tract and out through the same opening it entered. Because of this, tetrastomes have to wait until a full cycle of digestion is complete before eating again. 

After food enters one of the mouths, it goes through the "feather stomach" and into a second stomach further back used to chemically break down food. Once the food has been sufficiently dissolved and chemically altered, it comes back into the feather stomach where the tendrils absorb all nutrients from the liquid into the bloodstream. This process can take some time, and once it is completed the food is regurgitated. 

The feathers of the feather stomach are quite agile. They're able to leave the body through the mouth to manipulate food, and can expand in size under hydrostatic pressure. Some nutrients are absorbed outside of the body this way, especially if they need little digestion.

Muscular system


Tetrastomes have two different types of muscles working together by opposing each other. Each contracting muscle is also accompanied by an extending muscle; a muscle that provides movement by pushing instead of pulling. 

The extending muscles extend with hydraulic pressure, supplied by the circulatory system. The contracting muscles, however, don't truly contract; they're actually a type of shape-memory tissue that curls in a spiral spring-like pattern. When opposing contracting muscles and the accompanying extending muscles stretch out the coils, they're able to return to their original shape by being exposed to certain chemical conditions initiated by the nervous system. A similar type of tissue is present in the hearts of tetrastomes, although they don't form a spiral, instead bending and creasing to change their internal volume and cause a change in fluid pressure. 

Reproduction


In their larval stage, Tetrastomes are tiny, spherical creatures. They are often released into the sea or air as spores, only growing larger later on far from their parent. The vast majority of tetrastomes reproduce sexually, finding a mate while still in this larval stage. Once a suitable mate is located they permanently attach to them, eventually forming a large chimeric adult with a roughly homogeneous mixture of cells from both individuals. 

Chimeric tetrastomes only mix their genes when flowering; the rest of the time the two genotypes remain distinct. This "flowering" is a periodic event where sexually mature chimeras grow reproductive organs over their bodies, which they completely lack most of the time. In these "flowers" larval non-chimeric tetrastomes are produced, possessing a mixture of genes from both "parents" (who are really a single chimeric organism). When released, they spread via wind dispersal if the organism is land based, or drift through the methane if the organism is aquatic. Eventually, they will find larvae released from other individuals to bond with, and the cycle continues. 

In many more advanced organisms, chimeric adults play a role in finding suitable mates for their larvae to bond with. Higher tetrastomes can be far more intelligent than their larvae, so this greatly helps in ensuring their offspring fuse with only the best mates. In most species that do this, the chimera finds a healthy mate that meets its specifications, and engages in cross pollination with it, trading larvae. Not long after the process is complete, the now chimeric larvae are released into the air. However, some species do care for their young and instead plant them somewhere they can guard. 

Most advanced tetrastomes are also capable of asexual reproduction, growing chimeric flowers that produce chimeric larvae containing cells identical to each "parent". Whether an individual will prefer to reproduce sexually or asexually depends on how well it is thriving, and can change in response to various factors like food availability and frequency of injuries. This way, evolution occurs faster; if an individual has particularly good genes, they will spread rapidly in asexual copies, whereas in sexual reproduction there's a chance of the specific genes governing these advantages being lost in their offspring. On the other hand, if an individual is particularly ill suited to the environment, sexual reproduction offers a greater chance that at least some of their offspring will be fitter. Also, it ensures that when a population needs to change quickly to adapt to new conditions, there is greater variation within the population to select from, whereas once they have become optimally adapted change is slower and the gene pool is relatively stable. 

Senses


Most tetrastomes are blind, due to the lack of light that reaches into the oceans the first tetrastomes evolved in. Instead, they navigate using sonar, using the same organs utilised by many lineages for jet propulsion, a trait that has been retained by almost all groups even after moving onto land. Even with enough light on the surface to see, their sense of echolocation was already so well developed there was little evolutionary pressure for the development of vision. The fact that the moon's atmosphere is so dense contributed to this, as echolocation is more efficient in denser atmospheres than thinner ones.

At the end of each limb are three horn-like protuberances, jointed at the base, which vibrate in response to sound waves. These are their primary hearing organs. They are attached to extremely sensitive sensory organs that can detect even the slightest change in position. 

Tetrastome diversity


Although the most primitive tetrastomes have tetrahedral symmetry, many lineages, especially those that live on the sea floor or on the ground, have moved away from this ancestral form. The most noteworthy are the trilaterians, who use three of their limbs for walking, and mainly the forth for eating. While digestive organs do still exist in the legs, they are much less developed than those of the "head". This way, trilaterians have moved away from their ancestral tetrahedral symmetry, and instead posses triradial symmetry. 

Unlike some other worlds with low-oxygen atmospheres, like Amthalassa for example, surface tetrastomes have no need for an exoskeleton or even scales to protect them from UV radiation. While the moon does lack an ozone layer, the tholin layer serves a similar purpose, blocking most ultraviolet light from reaching the surface and protecting life from its harmful affects. The fact that they typically breathe through the skin also provides an evolutionary hindrance to the development of a protective covering. Most also lack endoskeletons, since under the low gravity there's little need for structural support for all but the largest organisms. 

The earliest tetrastomes possessed swim bladders, allowing them to remain buoyant in the methane oceans they inhabited. While it was originally filled with a heavier mixture of gasses, many tetrastomes, especially more "advanced" ones like trilaterians, have swim bladders filled with hydrogen. With the moon's thick atmosphere, this allows them to swim through the sky as if they were swimming through the sea; in fact, there are many organisms lacking these hydrogen swim bladders in the skies, staying airborne through their own muscular effort with relative ease. Often, they will look more like fish than birds.