The diminutive Methuselah clade, with backwards-pointing leg-joints which give them a gait something like a chicken, larger eyes and ears, and a marsupial-like pouch
Prelude - Life Extension during the Interplanetary Age
During the Interplanetary Age many attempts were made to extend the human lifespan. Medical therapy and somatic genetic engineering were used to reduce the rate of senescence in human bodies, but life extension involved many factors, each of which had to be dealt with separately. Osteoporosis, cancer, weakening muscles, clogging arteries, organ failure, genetic copying errors, and telomere degradation were only a few of the problems that had to be dealt with. Progress was slow, and optimistic projections frequently failed to eventuate.
By the late interplanetary Age a number of these problems had been identified, several had been ameliorated. With constant medical treatment and intervention it seemed that individuals could expect to live for several hundred years, although few had yet attained that age. But these anti-senescence treatments were limited by many aspects of the naturally-evolved human body; as the body grew older, problems with the backbone, joints, heart and senses all became increasingly acute. Some experts in life-extension advocated more radical measures.
The emergence of Homo methuselah
Biomodification in the 400s AT had become largely driven by fads and fashion. Funky feather eyebrows and scaly or leopard-fur skin were cool, a purely functional form that departed from the norm was not. A number of volunteers had agreed to radical changes that could avoid some of the lasting problems of old age, but these were not gentically inheritable. Many of the most radical experiments were conducted in non-aligned micronations like Academion, and in orbital habitats like Clarke Station and O'Neills One and Two, where restrictions on gene-line modifications were fewer.
By no means the most extraordinary of these experiments, but still one to have a great impact even so, was the Methuselah Project, initiated in 479 AT. A team led by Dr Darwin Jamie Pennak, superbright and part-time consultant for Biotopia, and ex-Modernbody biohack Patricia Heng, decided to pull out all stops and create a true Methuselah - "longevity as if aesthetics did not matter". They took the human body and decided to design it as if evolution had selected for longevity and functional life of arbitrary length without constant medical intervention. The result was what would have to be one of the least attractive of the "new species". Almost every part of the anatomy was redesigned on the basis of optimal function.
The most obvious difference was in the stature of the new species. The inefficient upright posture was replaced with a forward-leaning stance; the body was also tilted forward somewhat to relieve pressure on the vertebrae and the lower back. The neck was made thicker to support the head better. The height was reduced to help prevent falls and hip fractures caused by aging. Legs were redesigned radically, with the femur, tibia and fibular reduced in length and the ankle joint reconfigured into a springy, backwards-pointing 'knee'. From this joint long metatarsal bones led to a reduced foot with three strong toes.
Much of the internal anatomy, the digestive and urogenital tracts, glands, eyesight, and hearing were all redesigned. Arms were made stronger, resembling the musculature of a chimpanzee or gorilla; the heart was modified to resemble the efficient heart of a wolf or dog; the lungs were extended with airsacs resembling those found in birds, so that oxygen could be absorbed more efficiently on the inbreath and outbreath. The ears were enlarged and pointed, to increase the amount of sound they can conduct. They could also move back and forth to better focus sound. The cornea was optimised, balance and coordination improved, and more.
Perhaps the most radical modification was the pouch, based on the marsupial system for carrying their young. The result was a short, somewhat distorted humanoid figure, capable of fast running and with a permanently surprised expression.
Life in the Solar System, and Beyond
In 499 AT the first of the methuselahs, Adam-Methuselah, reached maturity in the Cislunar band. He was soon joined by his siblings. Although of normal human intelligence, they were not superbrights, as their whole purpose had been optimised life extension. The Methuselah Project closed soon after; in any case, Pennak, Heng, and the rest of the team had long since moved on to other things, taking the property rights of the methuselah genome with them. It was the low point of despair for the new parahumans. As Adam-Methuselah was later to say, perhaps with understandable bitterness, in his memoirs, "no-one was interested in ugly little dwarves who could live forever". But with the help of several human rights groups and a friendly AI, and after an extended legal battle, the methuselahs eventually got legal possession of their geneprint. They migrated up the Well to Clarke Orbital, where they were given citizenship and like many newcomers took the surname "ofClarke". The solar system was continuing to undergo colonization and development, and the robust and compact little methuselahs found work was available on the frontier, where no one cared what you looked like, as long as you could get the job done, and do it well.
With longevity and rejuvenation treatments available for those who could pay, the growing Methuselah clade were the first true immortals - their bodies were optimised for 200 year lifespans even without any treatment at all; with longevity treatment they could continue for literally thousands of years with little need for further augmentation. Many invested in long-term projects like Oort mining and interstellar development.
The attitude of the methuselahs to wetware and other such augmentations was variable. Although Adam-Methuselah ofClarke enthusiastically embraced the new technology "as a way of staying competitive", others, especially the faction headed by his younger brother Noah ofClarke refused to have anything to do with such things, an attitude Adam-Methuselah himself found puzzling. Most methuselah clans modified themselves further, to be resistant to space radiation damage and tolerant of microgravity, but some opted for radical augmentation and hybridization to the extent that they were no longer recognisably methuselan.
Thus, from even a relatively early period, the small clade was rent by dissensions and schisms. But in all this, Adam-Methuselah retained a firm hand of leadership, although some put this down to the influence of several superturing AIs, including Tarith-5 of O'Neill Two. Also Academion lent their support, having advised him with legal matters in the fight over Methuselah genome ownership, and may have been supporting the clade for reasons of their own.
Like many outward moving clades, the methuselahs were little affected by the Technocalypse that brought such devastation to the inner solar system, but the isolation of the surviving habitats only served to deepen the rift between the Adam-Methuselites, the Noaites, and the various cyborg factions of the clan. By the time the Federation had revived civilization, there were no less than half a dozen methuseline species and subspecies in the Sol System, and a couple more already outsystem from a few of the GAIA Arks, each of these ones claiming to be the "true methuselah". And while Adam-Methuselah's faction (the largest of the 6 solsystem clans) voted almost unanimously to join the Federation, most of the others, fearing assimilation or subversion, chose to remain autonomous.
The methuselahs found their talents in high demand in the Federation. As ships were not yet capable of relativistic velocity, there was need for long-lived bionts to serve as crew during the long voyage. The stolid, phlegmatic tweaks were quite happy to spend decades having the run of the ship, especially if there was a suitable commission (usually anywhere from 0.5 to 2% of new planetary development) as part of the deal. Not only many paranoid anti-ai groups, but even mainstream venture start-ups, found this a reasonable offer. As a result, the methuselahs grew very wealthy indeed. Even the emergence of relativist ships did not phase them, for not all corporations or individuals could afford the technology or the amount of amat needed to push a ship to such a high fraction of the speed of light.
With the development of the wormhole Nexus, the rise of the archailect empires, and the increasing availability of conversion and reactionless drive vessels, the methuselahs fell from prominence. Even so, managed investments ensured that those who wished to remain in the settled worlds could do in comfort and luxury. And those that wished to move outward to the ever expanding frontier, to find new worlds and investment opportunities, were also able to. Many established successful and long-lived populations in many of the ordinary (non-transapient managed) middle tech societies, and a lesser number of high tech societies, especially in the Inner Sphere and Middle Regions.
The Methuselahs Today
Among the Old Houses in the galaxy, methuselahs today are regarded as conservative, dependable, even dull. They have no pomp, no spectacle, little automation, no finery. They are more likely to invite the visitor into their habitat for a bulb of biofabricated coffee, and are known to raise a bemused eyebrow if afforded polite honorific titles. They have also changed remarkably little in the last ten thousand years. They still look like a baseline six-year old with pointy-ears on steroids. Most have minimal wetware augmentation, usually only enough to interact comfortably with household appliances and spacecraft control systems. Many have taken up a life on the spacelines, and often migrate to the Outer Volumes, where they enjoy doing the sort of long-term tedious maintenance work they have become renowned for.
None have ever breached even the first singularity toposophic - hence the expression "about as likely as a transapient methuselah."
References
Adam-24-c, My Life and other Stories, vol. 1, node e-iii, Eden Interactives, 3851 AT.
Adam-Methuselah ofClarke, Unfinished Memoirs, Atlantis Media Webooks, O'Neill Three, 1482 AT (reissued Alexandria Archives - Memory Node "C")
S. Jay Olshansky, Bruce A. Carnes and Robert N. Butler, Scientific American, March 2001 c.e. (31 AT) (reissued Alexandria Archives - Memory Node "C")
Darwin Jamie Pennak, Patricia Heng, Morris Mkome, and Sanyo Lee, (ed.) The Methuselah Project, Academion Modern Classics of Science, 2512 c.e. (543 AT) (reissued Alexandria Archives - Memory Node "C")