Fallout Taxonomy: Geckos
The Pedant returns from the thrilling world of botany to zoology. Beneath the cut: the humble Gecko, scourge of the Southwest!
The distinguishing characteristics of the four known types of post-War Gecko follow:
Enlarged size. All known species are greatly enlarged from pre-war populations, and even from the world's largest pre-War Gecko species, Rhacodactylus leachianus.
Bipedalism and body plan adaptation. The Geckos have evolved a generalized enlargement of the limbs and contraction of the torso to enable a habitual, if clumsy, bipedal gait. The neck of the Gecko has not contracted, leading to the characteristic bent and hunched posture. It is plausible that, over time, the Gecko's bipedalism will either revert to typical quadrupedalism or optimize due to physiological stresses. As the Geckos are not presently known to exhibit tool use or climbing behaviours, their bipedalism may well prove a negative adaptation.
A frill structure of unknown origin and purpose adorning the skull. It is likely that these frills enhance the hearing of the Gecko, though no pre-War Gecko exhibited any similar structure.
A lack of eyelids.
The Pedant suggests that it is the last two characteristics that provide the best guide in assessing the evolutionary history of the Gecko. To that end, we now turn to the emergence and distribution of the Gecko:
FIGURE 1: The approximate range of the Post-War Geckos.
The precise emergence of the post-War Geckos is uncertain. The earliest records available date from 2241, but these encounters pointed to well-established populations integrated into local economies and ecologies rather than to novel species. The sparse data available from the region in decades prior prevents easy extrapolation, and the absence of known populations further south into the 'central California' region suggests that the lack of records from that region in the 2160s may not indicate a later emergence of the species.
With this information, we suggest that the most likely origins of the Geckos - assuming they are not spontaneously arising populations unrelated to one another - lies in Northern Nevada or California. These locations were saturated with airborne FEV from strikes against West Coast military and research sites, and we believe this to be integral to the evolution of the Geckos.
We take as our initial hypothesis the following: The Gecko was not deliberately engineered but arose as a product of FEV-induced mutation (presumably FEV-2a) among co-distributed lizards.
We consider two specific characteristics of two species of Gecko as indicative, with one shared characteristic as further evidence. The first is the presence of enlarged spiny scales in all known populations of the Fire Gecko. The second is the ability of the Fire Gecko and Green Gecko to spray caustic, flammable, and poisonous liquids as a defensive mechanism. The third, shared trait is the frill structure.
The Pedant submits that these structures and abilities, which have no homologue among pre-War Gecko populations, derive instead from the Phrynosoma genus of 'horned lizards' or 'horntoads'. These species exhibit pointed scales and spines, prominent head crests, and the ability to squirt blood mixed with irritating and bittering agents as a defensive mechanism. Specifically, we nominate Phrynosoma hernandesi, the Greater Short-Horned Lizard, as the most likely candidate - it possesses these traits and overlaps with the most likely common ancestor of the post-War Geckos.
It is this latter that has proven more difficult to identify. We point to identifying characteristic #4 of the Geckos as indicative: the lack of eyelids. The species most commonly identified as a likely precursor, Coleonyx variegatus (the Western Banded Gecko), is a member of the Eublepharidae family of Geckos. This family is marked out in no small part by the presence of eyelids - something distinctly lacking among post-War Geckos - and by the absence of toepads, present among the post-War Geckos. As such, we reject the idea that the post-War Gecko constitutes a clade of the Coleonyx.
Instead, we believe the most likely candidate to be a non-native Gecko species - the common Mediterranean House Gecko, Hemidactylus turcicus. Widely distributed within the geographic range of the post-War Geckos, H. turcicus exhibits the slightly compressed bodily plan of these mutated specimens, lacks eyelids, is carnivorous, is vocal with a range of chirps and hisses, and are well known to establish themselves in marginal terrain including cave systems and arroyos. They exhibit the shared characteristic vertical pupils and variable striped colouration.
The origin of the bipedal adaptation remains enigmatic. Any number of sources may have contributed to the trait, though if we wish to remain within the realm of the lizard, any number of collared lizards endemic to the same shared range are prone to situational bipedalism. If this is the case - or worse, if primate or human DNA is a contributory factor, perhaps as part of a shared crossover event that produced the Tunnelers - then the Gecko represents a truly chimeric genus.
COMMON GECKO
FIGURE 2: The Common Gecko, first described Norton, Urquhart, et al 1998.
The common Gecko, also known as the Blue Gecko, Silver Gecko, and Little Gecko, is found across most of the Gecko's range, though they are largely absent from the Central Californian populations. These Geckos tend to be smaller than most - around three foot in height - and lack the characteristic spines and fire-breathing capability of the oft-mistaken Fire Gecko. It is a matter of mild dispute whether the Gecko of Nevada is the same species as the Silver Gecko of Southern Oregon, but the Temple finds inadequate evidence for speciation.
It is also not clear whether the Common Gecko - or indeed, any post-War Gecko - represents the shared root stock of the other Gecko clades. The Temple's tentative position is that they are the parent species of the Green and Gold Geckos. As a chimeric species, their placement is difficult, but we believe they retain a sufficiently 'gecko-esque' character to remain within the Gekkota, but within a new family, the Cristatogekkonidae, or Crested Geckos. The Cristatogekkonidae are at present a single-genus family.
We nominate the Gecko thus, as always using the tripartite schema for animal life of hierarchical taxon, niche taxon, and mythotaxon: Trekhogekko minimus Gekkoa maxima insectophagus Reptilia generica facilis
GREEN AND GOLD GECKOS
FIGURE 3: The Gold Gecko, first described Norton, Urquhart, et al 1998.
The Temple submits that there is insufficient evidence for speciation of the Green and Gold Geckos, with the two constituting environmental adaptations and morphs of the Common Gecko with which they remain co-associated. The differential colouration of the Gold Gecko we believe to be a reaction to oxidative stress thanks to their association with irradiated sites, which also grants them a contaminated and mildly radioactive bite - much like those of certain species of monitor lizard whose primary envomation is due to rapid onset infection rather than actual venom production (but not the Komodo dragon, which in fact is venomous.) With no other morphological difference beyond mere size (already highly variable among Common Geckos, especially of the Mojave distribution), the Gold Gecko appears to otherwise be near identical to the Common Gecko.
Accordingly, we suggest that no speciation is indicated, though we provide the following mythotaxon: Reptilia generica mediocris
The Green Gecko (first described Sawyer et al 2011) likewise exhibits minimal morphological deviation. It is capable of spitting venom and bears a green colouration well-suited to the comparatively lush environs of the Zion Canyon in which it is confined. It is possible that the Green Gecko arose independently via the same pathways as the Common Gecko, as it has no presence in other Gecko-hosting areas, but it is morphologically identical to the Common Gecko beyond colouration, size, and its ability to spit a poisonous substance. This, we believe, is an intermediary mutation shared with the Fire Gecko. Accordingly, we are prepared to nominate the Green Gecko as a subspecies, with the attached mythotaxon: T. minimus subsp. spielbergus Reptilia generica sputator
FIRE GECKO
FIGURE 4: The Fire Gecko, first described Norton, Urquhart, et al 1998.
The Fire Gecko presents the most remarkable variation within the Gecko family. Unlike the smooth-skinned Common Geckos, the Fire Gecko is a scaly, robust creature with prominent spines. This alone might be sufficient to suggest speciation, but there more baffling feature of the Fire Gecko is its ability to breathe fire. This ability is often ascribed to an association with 'sulfur-rich' environments, but this is unevidenced.
Without chemical assay, it is very difficult to assess how and why the Fire Gecko developed this capacity. However, we note that this mutation is not isolated - similar mechanisms have been observed in Eastern Floater populations and the Fire Ants known to occur in the Capital Wasteland and the Mojava. Both these other species are known to be the product of extensive FEV exposure, and this may present the origin of this peculiar capability. In the case of the Gecko and the Ant, a pyrophoric substance seems the most likely candidate, and in the Fire Gecko specifically, we suspect ignition occurs via an adaptation of the blood-squirting capability seen in the Horned Lizards.
Accordingly, we nominate the Fire Gecko thus: Trekhogekko draco Gekkoa maxima pyrophili Homodraco gekkoa formidablis
