Information:  - The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period million years ago (Mya) to the beginning of the Paleogene Period Mya. It is the last period of the Mesozoic Era. The Cretaceous Period is usually abbreviated K, for its German translation "Kreide" (chalk).  - The froghoppers, or the superfamily Cercopoidea, are a group of Hemipteran insects, in the suborder Auchenorrhyncha. Adults are capable of jumping many times their height and length, giving the group their common name, but they are best known for their plant-sucking nymphs which encase themselves in froth in springtime.  - Baissa is a lower Cretaceous locality in Siberia, on the left bank of the Vitim River. The Zaza Formation sediments exposed at Baissa are represented mostly by sandstones, siltstones, marls and bituminous shales. The total thickness if the section is about 80 m. Insect remains occur throughout the section, except for the most coarse-grained rocks. Their abundance and state of preservation vary from one bed to another.  - The Paleogene (or ; also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The Paleogene is most notable for being the time during which mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the CretaceousPaleogene extinction event that ended the preceding Cretaceous Period.   - The Jurassic (from Jura Mountains) is a geologic period and system that spans 56.3 million years from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period Mya. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period is marked by the major TriassicJurassic extinction event. Two other extinction events occurred during the period: the Pliensbachian/Toarcian event in the Early Jurassic, and the Tithonian event at the end; however, neither event ranks among the "Big Five" mass extinctions.  - Saurophthirus is an extinct genus of flea that represents a transition between primitive stem fleas , and modern species . The type species , S. longipes is found in early Cretaceous strata of Baissa , Siberia . The second species , S. exquisitus , is from the is from the Lower Cretaceous Yixian Formation .  - Insects (from Latin ', a calque of Greek ['], "cut into sections") are a class of invertebrates within the arthropod phylum that have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. They are the most diverse group of animals on the planet, including more than a million described species and representing more than half of all known living organisms. The number of extant species is estimated at between six and ten million, and potentially represent over 90% of the differing animal life forms on Earth. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, a habitat dominated by another arthropod group, crustaceans.  - A larva (plural "larvae" ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.  - Birds (Aves), also known as avian dinosaurs, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds or, less accurately, as songbirds.  - Mammals are any vertebrates within the class Mammalia (from Latin "mamma" "breast"), a clade of endothermic amniotes distinguished from reptiles and birds by the possession of a neocortex (a region of the brain), hair, three middle ear bones and mammary glands. The sister group of mammals may be the extinct "Haldanodon." The mammals represent the only living Synapsida, which together with the Sauropsida form the Amniota clade. The mammals consist of the Yinotheria including monotrema and the Theriiformes including the theria.  - Warm-blooded animal species can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The only known homeotherms are birds and mammals. Other species have various degrees of thermoregulation.  - Fleas are small flightless insects that form the order Siphonaptera. They are external parasites of warm-blooded animals, living by hematophagy off the blood of mammals and birds. The adults are up to about long and usually brown. They are flattened sideways to enable them to move through their host's fur or feathers, and have strong claws to prevent themselves from being dislodged. They are wingless insects, with mouthparts adapted for piercing skin and sucking blood and hind legs adapted for jumping. They can leap a distance of some 50 times their body length, a feat second only to jumps made by froghoppers. The larvae are worm-like with no limbs; they have chewing mouthparts and feed on organic debris.    What entity does 'saurophthirus' has the relation 'parent taxon' with?
A:
siphonaptera