This creature is clearly reptilian in nature, although it appears to be not only sentient, but also highly intelligent. Still, the underlying physiology is remarkably similar to a number of terrestrial species- including the venom sacks, which we might be able to synthesize and incorporate for use in our medical supplies.
Although I would expect to be more accustomed to seeing the clear intermingling of both human and alien genetic material, I must admit, this reptilian creature with such distinctive human features is surprisingly unsettling. Invasion-era reports include references to a species with some reptilian qualities, but nothing as readily apparent as this.
I find it truly remarkable how adaptable some of the alien species' genetics are to the constant "tweaks" they're often subjected to. In the case of the "Viper," a species once identified as the infiltration unit known as a "Thin Man," the aliens have made a conscious reduction in their efforts to disguise it's true form. Without the introduction of extensive human genetic material, the Viper reverts to a purely reptilian form while apparently retaining the same intellect and combat aptitude. The Viper's snake-like form is in many ways similar to the legless reptiles we commonly encounter on Earth. The enhanced torso musculature allows for upright mobility, and the addition of two physically weak but capable arms allows for the handling of traditional weaponry. Of the many aliens species our troops encounter in the field, I find the prospect of encountering an intelligent snake standing over 2 meters tall to be among the most disturbing. R.Tygan