Tumgik
#shellback crab
sixteenseveredhands · 11 months
Text
Shellback Crabs: these crabs create their own shields out of clamshells; they have semi-membranous bodies that can be pressed into the contours of a shell, producing a suction mechanism that holds the shell in place
Tumblr media
The members of this genus (Hypoconcha) have a series of unique adaptations that facilitate this kind of camouflage behavior. Many of the Dromiidae crabs (e.g. hermit crabs, sponge crabs, shellback crabs, etc.) are equipped with a specialized pair of legs that enables the crab to hold a shell, sea sponge, and/or ascidian against their body, but shellback crabs also have a flexible, semi-membranous body that can be tucked more firmly into the contours of a bivalve shell, producing a suction mechanism that keeps the shell firmly locked in place.
Tumblr media
The body of the shellback crab is also covered in a very fine layer of hair-like structures called setae, and when the crab presses itself against the shell, these membranous "hairs" can take on an almost translucent appearance, particularly around the margins of the crab's body.
Tumblr media
I recently posted some photos/info about some of the crabs in the genus Lamarckdromia (which belongs to the same family) and as I was doing the background research for that post, I was just kind of mesmerized by all of these weirdly adorable crabs that seem to exist within the Dromiidae family tree. Each genus has its own unique adaptations that allow the crabs to use specific materials for camouflage -- some of them use living sponges, clamshells, ascidians, etc.
And I could not stop laughing at the little faces on these crabs. They've all got the same bemused/indignant expression...as if some random asshole has just walked up to them, shoved them over, and announced to the entire ocean that there's a crab hiding beneath that disguise; as if that actually happens to them quite a lot, and they're getting really sick of it.
Tumblr media
Sources & More Info:
Crustaceana Monographs: Comparison of the Shell-Carrying Behaviors of Desmodromia, Conchoecetes, and Hypoconcha (the relevant info is on page 191)
South Carolina Department of Natural Resources: Shellback Crabs and their Larval Stages (PDF)
South Carolina Public Radio: Shellback Crabs
Again, I don't normally feature crustaceans on my blog...but I really couldn't resist this one.
12K notes · View notes
plurble · 2 months
Text
Tumblr media
starting something new to keep my mind active - an Invert. Journal! i’m gonna start recording some of my favorite/interesting invertebrates and include some neat facts!
Hypoconcha sp.
including a picture of the Real Thing because my drawings can vary
Tumblr media
2 notes · View notes
entomoblog · 2 months
Text
Ces crabes créent leurs propres carapaces à partir de coquilles
See on Scoop.it - EntomoScience
Shellback Crabs: these crabs create their own shields out of clamshells; their semi-membranous bodies can be pressed into the contours of the shell, producing a suction mechanism that holds the shell…
  Artifacts, Arthropods, and Anthropology on Tumblr
sixteenseveredhands
  via Taupo @[email protected] sur X : "Les crabes hypoconches, mes prefs, ça change pas !" https://twitter.com/pierrekerner/status/1761360345153548360
  -------
NDÉ
Traduction
  "... leur corps semi-membraneux peut être plaqué dans les contours de la coquille, produisant un mécanisme de succion qui maintient la coquille en place.
  Les membres de ce genre (Hypoconcha) possèdent une série d'adaptations uniques qui facilitent ce type de comportement de camouflage. De nombreux crabes de la famille des Dromiidae (bernard-l'ermite, bernard-éponges, crabes à dos de coquille, etc.) sont équipés d'une paire de pattes spécialisées qui leur permet de tenir une coquille, une éponge de mer et/ou une ascidie contre leur corps, mais les crabes à dos de coquille ont également un corps flexible, semi-membraneux, qui peut être pressé plus fermement dans les contours d'une coquille de bivalve, produisant un mécanisme de succion qui maintient fermement la coquille en place."
0 notes
therealvagabird · 4 years
Text
The Days of Clay - Pt. 2: Beasts, Peoples, and Class Concepts
Part 2 of my paleo/neolithic RPG setting concept. Here are the concept overviews for the more “living” aspects of the world.
You can read the full setting rundown all at once on my WordPress.
Feel free to a leave a comment, and share!
Saurians
Found throughout the tropical and otherwise hot regions of the world, from searing deserts to sweltering jungles, saurians are a common form of fauna across the equatorial continents. Though most saurians are quite similar to all other animals – skittish, of varying size, and uninclined to hunt humans save under ideal circumstances – the great Thunder Lizards are well feared, and stories of them are known the world over in tales of dragons and other great wyrms. Saurians are cold blooded and include such species as the tyrannosaur, the carnotaur, velociraptor, and oviraptor as prominent therosaurs. There are also the mighty thagosaurs, the ceratops, brachiosaurs, and diplodosaurs as among the grandest of the Thunder Lizards. The hunting of these beasts outstrips even the danger of hunting Great Mammals like the mammoth, though that has not stopped some of the most fearsome warrior-tribes from attempting and succeeded at such feats. Tales of the taming of Thunder Lizards are also common, though even less substantiated. Not that factuality matter more than a good story to most shamans and their listeners.
Ape-Men
Ape-Men comprise all those varieties of bipedal or mostly-bipedal humanoid creatures who straddle the line between ape or monkey and man. Those who live in areas where there are no ape-men to be found might think that the distinction between an ape-man and a monkey, or an ape-man and a rather blunt and hairy person might be indistinguishable. Those who have ever seen an ape-man know the uncanny appearance by which those creatures can be identified. Though some believe that the ape-men are just as intelligent as humans, they have no language, no writing, and use but the most primitive of technologies. Some are quite small, while larger breeds can also be found, even in high altitudes and frigid environs. Most ape-men tend to cluster in basic den formations, and though they will not craft tools or shelters, they are sometimes smart enough to set up basic lean-tos, making use of existing caves or other helpful geography, and may pick up and utilize bones and rocks as basic weapons and the like. Though not very violent by nature, ape-men tend to compete for similar habitats as humans, and so often come into conflict with them. Ape-men clans who have lost great numbers to humans before tend to avoid all future confrontations even generations later.
Lizardmen
Similar to ape-men, lizardmen are the various breeds of bipedal, dexterous lizards who can sometimes be found in the territories of other saurian species. Little is known about how they differ from other scaled creatures save for their intelligence. Like ape-men, despite not having any known language or culture, the lizardmen have shown some ability to use tools, and tend to cluster in social groupings. Many of these dens are found in places most humans know as “Shatterlands” – angular rock formations common in deserts and some jungles, which various lizardmen of different species seem to all gravitate towards as ideal homesteads, even displacing other saurians in the process. Lizardmen range from the great crocolids and saurids to the more diminutive skinks and kobolds. They are uncommon outside of their usual ranges, and some say they are even dying off little by little.
Great Mammals
Found throughout the world, though most of all within the great tundra of northern lands like Batyr, Siral’ik, or Dziil, there are those creatures known as the Great Mammals. Also known as Great Beasts or Great Hairy Ones, these are the mammalian creatures who nonetheless rival the largest saurians in size and power. Mammoths, shellbacks, giant sloths, sabercats, dire wolves and dire bears – these are a source of both great danger and great plenty to those tribes who share their lands. Some Great Mammals may be found in southern reaches, such as with the giant ape-kin, or the elephants, giraffes, and the like which wander the savannahs of Noba Rugna. It is uncommon for saurians and Great Mammals to share habitats, though the bloodletting when the two come into contact can be significant and godlike.
Great Coldbloods
Separate from the saurians, Great Coldbloods is a catch-all term for creatures such as the giant snakes, colossal toads, and other creatures which do not share the same general markers of “true saurians” like the therosaurs, brachiosaurs, or ceratops. Though the distinction is rather vague, it is important to tribal peoples who live in southern lands, as Great Coldbloods tend to not be as aggressive and predatory as saurians – they are no less dangerous, but they prefer to stick to their well-defined hunting and ambushing grounds. Some Great Coldbloods are significant enough to take on and fell saurians in their own right, and command just as much fear as any other terrifying predator.
Great Shellhides
Perhaps the broadest category by which the human tribes of the world define the largest types of various animals, Great Shellhides comprise all those cold-blooded, hard-skinned, and boneless creatures which crawl beneath the earth. Though most “bugs” are insignificant things perhaps defined by powerful poisons to compensate for their size at the deadliest, Great Shellhides are monstrosities able to go claw-to-claw against other Thunder Beasts and Great Fauna. Hellspinners, elephant beetles, stoneborers, sand-devils – though some can be quite docile despite their size, most pose significant threats to any humans who dare to trifle with them. Within the seas there are also the giant crabs, temple clams, and devil-lobsters, among others. Though most hunters would not dare attempt to assault any Great Shellhide due to their impervious armor and the terrible ways they are capable of killing, the promise of tender blue-meat and a rich supply of chitin for crafting means that to many, the risk is worth the reward.
Leviathans
Encompassing all those beings which make sailors quail at the mere mention of their names, there are the seabound leviathans. Leviathans are not a single species, nor even a clade, but rather a term for any aquatic monster which is defined by its immense size. Whales are often considered leviathans, along with the great sharks such as the megalodon. More terrible are the leviasaurs – mosasaurs and ichthyosaurs and the like. Kraken, or the god-squids, are another class much feared by all who know of them, as well as the sea-serpents and dragon-turtles. Despite their fearsome reputation, most leviathans pose no great threat to humans, confined as they are to the abyssal sea. It is more common for even the bravest of seafaring tribes to meet their end by exposure or storms than by the direct attack of a leviathan, though that is seldom comforting to most sailors. The hunting of leviathans is considered by many to be the penultimate feat of prowess – to slay something as large and terrible as a Thunder Lizard, yet within their own element.
Giants
Sometimes conflated with ape-men, giants are among the rarest of all the near-human species. Defined as massive humanoids, tending to display blunted manlike features and standing anywhere from over two to five times the height of an adult human. Giants are usually found in reclusive dens, or solo, in the wilder areas of wherever humans might be found. The very largest are confined to the north and far east, in the most remote reaches of lands like Fjallgarth and Siral’ik. Little is known of giants, save for their prodigious size, ferocity when challenged, and rather hideous appearances. Much like ape-men, lizardmen, or parcies, they seem to have no higher culture, yet maintain a level of intelligence above most base animals. They may use fallen trees or great stones as makeshift tools, and some have even been said to herd Great Mammals, though it is unknown if there are any truth to these stories, or if the giants merely hunt such beasts. Most giants prefer to avoid humans when they can, unless in a desperate or vengeful position, as it is a common feat of strength for warriors of the northern lands to seek out and slay giants when they can.
Parcies
Pronounced “park-ees” and often referred to as “little folk”, “sprites”, “gremlins”, and numerous other regional names. Parcies are a strange class of creatures believed to be offshoots of humans or ape-men. Though there are many different breeds of parcie, they are often defined by short stature, and intelligence somewhere between humans and beasts. Humans born with conditions such as dwarfism may be confused with or referred to as parcies, but it is known to most who have encountered the little folk that they comprise their own group of species altogether. Most parcies are shrouded in mystery, living far away from humans, and maybe engaging in clandestine theft if they need to. Kidnappings, misfortunes, and other ills are sometimes attributed to parcies, though good luck and positive happenstances may also be called the work of parcies. While most are reclusive and nonviolent, they have been known to attack humans if threatened. Taking inspiration from certain parcie stories, some humans have even “tamed” parcies as servants or pets when they can. Notable breeds of parcies include brownies, gremlins, tomtens, dzedka, memegwesi, memegwaans, and nimerigar, A singular parcie can also be called a parca.
Humans:
Wisewalkers
Most humans throughout the world are of the breed known as “wisewalkers”. Though there are just the most minimal of differences between the different human subtypes – beyond even more tertiary traits such as skin color, cultural inclinations, or habitat – some distinct traits can be identified. Wisewalkers tend towards being the least hirsute of the human breeds, and the most inventive. The grander settlements of human make have oft been the work of wisewalkers, and the technologies they have pioneered are impressive. Though not so strong or swift as their cousins, the mental acuity of the wisewalker breeds has seen them become the most prolific of all humans.
Hobblehands
Smaller than wisewalkers, hobblehands are known for their great agility and cleverness. Though they are not quite as inventive as their larger cousins, they are quick learners and were the first creators of many basic tools that the wisewalkers would later improve. Standing about three to four feet tall on average, hobblehands are named for their dexterous skills, making for great ambush-hunters and adept crafters of small implements. They tend towards darker or ruddy skin tones depending on region, with curly hair, and round-featured faces that some have said look halfway between an adult and a child – though not in the same way an adolescent’s does. Hobblehands can be distinguished from dwarves or parcies by their proportions, looking rather like full-grown humans of a smaller size. Most hobblehands tend to live within their own tribal communities, and though they are not often leaders of mixed societies, they are much appreciated as crafters by the wisewalker shamans.
Neanders
Large, muscled, and brutish in appearance, the neaders are the human breed most known as warriors and hunters. Stereotypes of their low intellects and blunt affect obscure a significant truth, however – that the neanders are just as sharp and clever as any human strain. Most often found in the north, neanders stand about the same height as wisewalkers, though tend to hunch and have an overall more apelike physique. Besides these differences in build, they are the closest to the wisewalkers in terms of overall appearance. They possess greater strength than wisewalkers, and significant stamina. However, though they have displayed no less cleverness than their cousins, they seem to lack a certain degree of inventive spark. Neander tribes – perhaps due to their skill at hunting – tend to eschew higher technologies if they feel they have no need of them. Sometimes battling their wisewalker neighbors, many neander tribes have been brought into the fold of larger wisewalker gatherings for their might and skill.
Wildlings
A class of humans who straddle the line between true humans and ape-men, wildlings far exceed the strength of the neanders and the agility of the hobblehands – yet unlike those two sub-species, they are marked by a noticeable lack of higher cleverness. Though still capable of tool crafting and the basics of human civilization, wildlings are not very inventive, and prone towards blunt solutions even when it might not be in their best interests. They prefer the wilds from which they take their name, eschewing large gatherings in favor of tight-knit tribes. The most physically adept of all humankind, they tend to be feared and mocked by their cousins, though like the neanders they may be contracted as formidable warriors. As they are so skilled at survival, most wildlings are content in their primitive ways, wanting for nothing more than the bounty their own two hands can bring them. They are often hunched and quite hairy, with apelike visages, though otherwise human in appearance. Their most common roaming grounds are in the southern grasslands and forests, though they may also be found anywhere in the deep wilds that they have staked out for hunting and foraging, from the frozen north to the burning south.
Class Concepts:
Magic is nonexistent in the known world, but that does not mean that mysticism and superstition are absent. Neither does it mean that these belief systems are without merit or use. Shamans, witch doctors, prophets – these are individuals who act as storytellers, leaders, and the glue which holds entire tribes and even emerging states together. Many possess skills of great importance, not bound to one cultural context, such as knowledge of herbs and natural substances, knowledge of crafting and building, or an uncanny memory for the behaviors of animals or the patterns in the weather. For some, belief is a powerful force in and of itself, with warriors and magicians able to work themselves into states of mania which help them endure beyond typical limits. A human can only do so much with their body, even at the strongest, but knowledge and faith are what set humanity apart from the other beasts.
Warrior
A versatile hunter of both men and beasts, able to specialize in various types of weaponry and combat-craft. Warriors, depending on tribal background or personal preference, may choose to focus heavily in certain talents, or diversify for the sake of adaptation. In some places, like the city-states of Sakha, warriors are free to spend more time mastering the arts of combat, given that they do not have to worry as much about base survival. Wilder types may not be as refined in their martial talents, but know the arts of hunting and foraging, or even translate knowledge of poisons and clever crafts into effective fighting supplements.
Shaman
The cornerstone of most tribes is the clan shaman – the priest, the healer, and the storyteller. Shamans, much like warriors, are as varied as the flowers of the field, or the birds of the sky. They blend concrete knowledge and skills with a flair for the dramatic, able to command great respect for their wisdom. Shaman may specialize in many fields, such as healing, inspiring their allies, lore of the wilds, and afflicting their foes with terror or poisons. Some shaman may hold combat knowledge, but for the most part these figures are noted for the stories they tell and the knowledge they keep rather than any outstanding physical abilities. Memorized lore of humans, beasts, plants, seasons, and more can all be utilized by a shaman in order to achieve their ends, whether that be leading their flock to prosperity, or leading their enemies to their doom. Though many think the skills of the shaman to be magic, most of the time trained wisdom and a perceptive nature is just as good.
Skinchanger
One art renowned and feared across the wide world is that of the skinchanger. Shamans who specialize in channeling the spirits of beasts, skinchangers may hone a number of abilities based upon their chosen spirit-animals. Skinchanging requires two physical components – a hide, and a mask. These shamans undergo extensive training in their youths to assume the mind of a given beast, studying their quarry for months and even years so as to learn what it is to be that animal. Then, they must slay that given beast and take its hide, as well as craft a mask from its remains. By donning these, the skinchanger enters a unique mania granting them the power of that beast. Though no real change comes over the individual, they are not to be trifled with. The pelt of a bear or a saurian is still a great armor, and when the person wearing it is bearing a set of claw-gloves and has worked themselves into a frenzy, even great warriors can succumb to terror. Other skinchangers may pursue less “direct” approaches, such as by donning armor made from the carapaces of creatures like the Hellspinners, stalking the high treetops, besides others. Skinchangers learn much by studying their given animals – of which they may have several, should they choose to carry several costumes – such as techniques for climbing, digging, using poisons, foraging, and hunting.
Berserker
Similar to the skinchanger is the berserker, who trains themself to enter a blood-frenzy during battle so as to shrug off injuries which would incapacitate other humans. Berserkers are defined by their great martial skill, and the means by which they enter their blood-frenzy. Some channel simple rage, while others call upon totem spirits or other shades to empower their bodies, and some make use of more literal bloodlust or even strange herbal concoctions. These warriors tend towards a very direct style of combat, favoring brute strength over more diverse or subtle means, yet berserkers tend to also be noted for the various skills they accrue in training their blood-frenzy. Berserkers may be quite knowledgeable in techniques of survival, or hunting, or herbalism as dependent on their backgrounds. For one to rely on strength alone is not enough, however mighty, and so berserkers tend to hide greater wisdom than meets the eye.
Boxer
Somewhere between a healer and a fighter, boxers are set apart from more typical warriors by their deep and intimate knowledge of the human body. Boxers are fighters who have received a degree of training as bonesetters, spiritual healers, or even chirurgeons. A boxer may in combat leverage this knowledge to target their enemy’s pressure points or vital organs, while out of combat they may apply the same techniques to their allies to alleviate pains or fix physical ailments. Boxers pay for their very specialized skillset by struggling in circumstances outside their training. They do not fare well against beasts lest they have knowledge of their anatomy and are not as able as dedicated healers to treat diverse illnesses. They do not do well in armor and may only competently use a set number of specific weapons. Still, the arts of the boxer are much respected by those who know of their reputations.
Beastmaster
The taming of wild animals is not an uncommon calling among certain tribes. Many warriors may hew closer to the path of the hunter, appreciating the company of a loyal hound or boar. Certain shamans may keep birds or other noble creatures as pets, believing them to grant good fortune, or training them to perform useful tasks. Skinchangers go a step further, and attempt to emulate and become as beasts. Beastmasters focus first and foremost on breaking the wills or otherwise earning the trust of wild animals of all stripes, allying themselves to the might of nature. These individuals are much more skilled at taming a larger variety of creatures than a typical hunter might, though even when they choose to simply use a dependable hunting-wolf, it is likely that their wolves will be better trained, and they will be able to command more of them at once. Some beastmasters end up taming great and fearsome beasts like saurians, great mammals, shellhides, and the like. They may even use such massive creatures as mounts. Others could specialize in directing much greater groups of smaller beasts. This could range from a small pack of hunting dogs, to entire swarms of vermin. If a beastmaster is able to safely forage and care for something like a wasps’ nest or a rodent warren-queen, they may even tame a whole horde of tiny pets.
Crafter
Creating things such as tools and shelter is a must-know skill for any human in the wide world, but for some it is more than a simple necessity. Some pursue the knowledge of material things the same way shamans pursue stories, or beastmasters and skinchangers pursue animal lore. Crafters specialize in creating items of exceptional make and identifying the uses of various materials. Bone, stone, wood, hide – even rare metals such as copper – all of these can be put to a multitude of uses by crafters, such as the making of weapons, tools, talismans, and more. Other crafters may specialize in larger projects, such as masonry, forestry, or boatbuilding. The downside is that crafters do not often make for good warriors or hunters and cannot be expected to do much more in combat than level their tools against the foe – though those tools are bound to be of exceptional make. Yet many bands of tribals do well to have one or more dedicated crafters among them, as just as they can put rare materials to good use, they are also quite adept at dismantling things. This can range from skinning a beast to chiseling a hole in the weak portion of a stone-brick fort. Likewise, groups with crafters always tend to accrue more loot, as crafters are skilled at pulling every last thing that could be of use from a fallen beast or a resource-rich area.
2 notes · View notes