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Helodermatidae
The Helodermatidae or beaded lizards are a small family of lizards endemic to North America today, mainly found in the Isthmus of Tehuantepec in Oaxaca, the central lowlands of Chiapas, on the border of Guatemala, and in the Nentón River Valley, though they were formerly more widespread in the ancient past. Traditionally, the Gila monster and the Mexican beaded lizard were the only species recognized, although the latter has recently been split into several species. While the fossil record of this family may date back to as far as the Cretaceous with genera such as '' Primaderma'' and '' Paraderma'' of North America, the oldest definitive members of the Helodermatidae date to the Early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ..., with '' Lowesaurus matthewi'' fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heloderma
''Heloderma'' is a genus of toxicoferan lizards that contains five species, all of which are venomous. It is the only extant genus of the family Helodermatidae. Description The genus ''Heloderma'' contains the Gila monster (''H. suspectum'') and four species of beaded lizards. Their eyes are immobile and fixed in their heads. The Gila monster is a large, stocky, mostly slow-moving reptile that prefers arid deserts. Beaded lizards are seen to be more agile and seem to prefer more humid surroundings. The tails of all species of ''Heloderma'' are used as fat-storage organs. The scales of the head, back, and tail are bead-like, containing osteoderms for better protection. The scales of the belly are free from osteoderms. Most species are dark in color, with yellowish or pinkish markings. Venom The venom glands of ''Heloderma'' are located at the end of the lower jaws, unlike snakes' venom glands, which are located behind the eyes. Also, unlike snakes, the Gila monster and beaded li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gila Monster
The Gila monster (''Heloderma suspectum'', ) is a species of venomous lizard native to the Southwestern United States and the northwestern Mexico, Mexican state of Sonora. It is a heavy, slow-moving reptile, up to long, and it is the only venomous lizard native to the United States. Its venomous close relatives, the four Mexican beaded lizard, beaded lizards (all former subspecies of ''Heloderma horridum'') inhabit Mexico and Guatemala. The Gila monster is sluggish in nature, so it is not generally dangerous and very rarely poses a real threat to humans. However, it has a fearsome reputation and is sometimes killed despite the species being protected by state law in Arizona. History The name "Gila" refers to the Gila River Basin in the U.S. states of Arizona and New Mexico, where the Gila monster was once plentiful. ''Heloderma'' means "studded skin", from the Ancient Greek words (), "the head of a nail or stud", and (), "skin". The species epithet ''suspectum'' comes fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurheloderma
''Eurheloderma'' is an extinct genus of heloderm lizard known from the late Eocene of France. It is the oldest confirmed member of Helodermatidae. References Prehistoric lizard genera Helodermatidae {{Paleo-lizard-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexican Beaded Lizard
The Mexican beaded lizard (''Heloderma horridum'') or beaded lizard is a species of lizard in the family Helodermatidae, one of the two species of venomous beaded lizards found principally in Mexico and southern Guatemala. It and the other members of the same genus, including the Gila monster (''Heloderma suspectum''), are the only lizards known to have evolved an overt venom delivery system. The Mexican beaded lizard is larger than the Gila monster, with duller coloration, black with yellowish bands. As it is a specialized predator that feeds primarily upon eggs, the primary use of its venom is still a source of debate among scientists. This venom has been found to contain several enzymes useful for manufacturing drugs in the treatment of diabetes, and research on the pharmacological use of its venom is ongoing. Threatened throughout its range by overcollection and habitat loss, it is a CITES protected species. The Guatemalan beaded lizard (''H. charlesbogerti'') is one of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lowesaurus
''Lowesaurus'' is an extinct genus of heloderm lizard known from the Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ... of the United States References Reptiles described in 1986 Helodermatidae Prehistoric lizard genera {{Paleo-lizard-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraderma
''Paraderma'' is an extinct genus of lizard. it is primarily known from the late Cretaceous Lance Formation. ''Paraderma'' is taxonomically disputed. When it was discovered in 1964, it was assigned to Parasaniwidae, but was reassigned to Helodermatidae in 1983. The most recent study has placed it solidly into Monstersauria Monstersauria is a clade of Anguimorpha, anguimorph lizards, defined as all taxa more closely related to ''Heloderma'' than ''Varanus''. It includes ''Heloderma'', as well as several extinct genera, such as ''Estesia'', ''Primaderma'' and ''Gobid .... References Reptiles described in 1964 Helodermatidae Prehistoric lizard genera {{Paleo-lizard-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lizard Families
This is a list of the extant lizard families. Lizards are an paraphyly, informal group of Squamata, squamates. Taxonomy There are five infraorders which separate the lizards, these are- Diploglossa, Gekkota, Iguania, Platynota and Scincomorpha. This separation is based mainly on morphological similarities between family groups. The Diploglossans and Platynotans are two closely related infraorders which are very diverse families. Very few generalisations can be placed upon these families morphologically. Many species are limbless, while others have fully formed limbs. It is believed that these lizards are the closest lizard relation to the snakes. The Gekkotans are the second most diverse group of lizards. They can be morphologically distinguished by the absence of temporal arches, which allows greater moveability of the head. Most species also have cloacal sacs and fixed eyelids. The Iguanians are another diverse group of lizards. All iguanians are fully limbed. Most species amb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene
The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing Ice age, glacial cycles of the Quaternary, and is equivalent to Marine isotope stages, Marine Isotope Stage 1. The Holocene correlates with the last maximum axial tilt towards the Sun of the Earth#Axial tilt and seasons, Earth's obliquity. The Holocene corresponds with the rapid proliferation, growth, and impacts of the human species worldwide, including Recorded history, all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban culture, urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global significance for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Edward Gray
John Edward Gray (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for a zoological name. Gray was keeper of zoology at the British Museum in London from 1840 until Christmas 1874, before the natural history holdings were split off to the Natural History Museum. He published several catalogues of the museum collections that included comprehensive discussions of animal groups and descriptions of new species. He improved the zoological collections to make them amongst the best in the world. Biography Gray was born in Walsall, but his family soon moved to London, where Gray studied medicine. He assisted his father in writing ''The Natural Arrangement of British Plants'' (1821). After being blackballed by the Linnean Society of London, Gray shifted his interest from botany to zoology. He began his zoological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geological period of the entire Phanerozoic. The name is derived from the Latin , 'chalk', which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation . The Cretaceous was a period with a relatively warm climate, resulting in high Sea level#Local and eustatic, eustatic sea levels that created numerous shallow Inland sea (geology), inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was largely ice-free, although there is some evidence of brief periods of glaciation during the cooler first half, and forests extended to the poles. Many of the dominant taxonomic gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
