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(Vagusinfluminus planapus)
Main image of Lamarpede
Species is extant.
CreatorDisgustedorite Other
HabitatMaineiac Temperate River, Maineiac Temperate Riparian, Maineiac Montane River, Maineiac Montane Riparian, Maineiac Lake, Maineiac Temperate Palus, Maineiac Marsh, Maineiac Mudflat
Size8 cm long
Primary MobilityUnknown
DietHerbivore (Maineiac Bubbleweed, Bubblebush, Shelterkelp, Bubblily, Yanisflora, Maineiac Orbion, Baebula, Polyprong Orbush, Marbleflora, Pioneeroots, Flashkelps, Larands, Sunstalks, Supershrooms, Vingrasions), Detritivore
RespirationPassive (Porous Cuticle)
ReproductionAsexual (Waterborne Spores), Embryonic Genetic Exchange
Vagusinfluminus planapus

The lamarpede split from its ancestor. Descending to the riverbed where it can seek out new food sources, it lost its flat body and leaf mimicry in favor of a rotund form colored in reds and browns suited to disguising itself in the reddish substrate found along the Maineiac watershed. Its butt-bubble now mimics its own head, confusing potential predators into biting the wrong, less important end of its body. It is semi-aquatic, its ancestral cuticle allowing it to easily survive on land for short periods of time to escape from aquatic predators such as shockers, freshwater seaswimmers, lyngbakrs, scorpodiles, gilltails, and larvabacks. It must still return to water periodically, as the pores it breathes through, though microscopic, can't be closed and will thus cause it to lose water if it stays on dry land for too long. A pair of photoreceptive patches atop its head alert it if it's exposed to direct sunlight so that it may quickly retreat back into the water. Like all krakowpedes, while its skin does contain chitin (which is why some of its relatives were affected by the chitinbane), its exoskeleton is primarily made of sclerotized collagen which grows as it does rather than shedding, making it more comparable to a turtle shell than to an arthropod exoskeleton.

The lamarpede's legs are more robust, and like other anipedes it only has two segments per limb. However, an unsclerotized pad is present at the end of each one, giving it some degree of limb-tip motion which helps it crawl over mud and rocks without sinking or slipping. The tips of its antennae are also unsclerotized, giving them a floppy, whip-like appearance. It has a semi-erect posture as a consequence of its arboreal ancestry and having to work with so few limb segments. Its limbs are mostly controlled with tendons, only containing any muscle at all at the shoulders/hips.

Much like its ancestor, the lamarpede is mostly herbivorous. It naturally produces cellulase in its gut, as the enzyme is present in all krakowpedes due to their distant ancestors technically being purple algae which needed it. It produces even more of these enzymes than before and its beak is more robust, as it also feeds on terrestrial flora that are much richer in cellulose and tougher to gnaw through than bubbleweeds. A tongue-like structure—the precursor to which is ancestral to anipedes—aids it in manipulating food to be swallowed.

Embryonic Development and Genetic Exchange

Some of the evolutionary adaptations of the lamarpede are enabled by the appearance of genetic exchange, but to understand how it works, one must first understand the bizarre embryonic development of krakowpedes. The lamarpede produces unicellular waterborne spores from a line of openings on its underside on each body segment which all have the potential to become an embryo, similar to most of its relatives. The earliest stages of the krakowpedian embryo are unusual among Sagan 4's fauna, however—instead of dividing into a ball of cells and then shaping into a fetus, a single cell grows into a unicellular "fetus" first and then undergoes a unique internal division process where it becomes a number of distinct cells in a chain each corresponding to a single segment, 7 of them in the case of the lamarpede (the butt bubble is technically supported by a highly derived terminal segment). The chain is formed one cell at a time from front to back. At this point, at which it is called a halusiblast (literally "chain-embryo"), it becomes a functional, motile, soft-bodied organism which crawls on the sediment and mostly feeds on cells and microscopic debris using a cell mouth. It undergoes more internal division as it grows, eventually becoming more properly multicellular and gaining its primarily collagen-based exoskeleton. (Of note, this means that krakowpedes by default have determinate cleavage, but having a unicellular fetus stage still leaves them open to developmental errors; the distantly related Trirhaches, for instance, achieved their characteristic radial symmetry through an error in their unicellular phase)

This unique ontogeny is a curiosity on its own, as no group of organisms on Sagan 4 develops in this manner apart from the krakowpedes, but even more curious is the lamarpede's unique method of modifying this for genetic exchange. Most other krakowpedes opted to turn the spore into a sort of gamete stage. However, the lamarpede exchanges genes during the halusiblast stage. Under environmental stress, the independent halusiblasts will halt their development and seek out other halusiblasts. They pair up side to side and undergo cellular mating, producing 6 zygotes which undergo meiosis into 4 spores each—resulting in 24 total spores produced. These spores then grow into new embryos with new genes, and provided the stress is relieved, they will eventually become adults. Because of the embryonic meiosis, lamarpedes are haploid.