Cnemidophorus
Encyclopedia
Cnemidophorus is a genus
of lizard
s which belong to the family
of Teiidae
, which are commonly referred to as whiptail lizards or racerunners. Note that the nomenclature
for this genus has recently been re-examined by T. W. Reeder et al. in 2002. Many species that were Cnemidophorus should now likely be considered Aspidoscelis
based upon divergent characters between the two groups.
, there are no males, and they reproduce through parthenogenesis
. This is well-known in bee
s and aphids, but is very rare in vertebrate
s. Those species without males are now known to originate through hybridization, or interspecific breeding. Occasionally, a mating between a female of one species and a male of another produces a parthenogen, a female that is able to produce viable eggs that are genetically identical to her own cells. The lizards that hatch from these eggs are thus also parthenogens that can again produce identical eggs
, resulting in an asexual, clonal
population. Parthenogenetic species resulting from a single hybridization are diploid (that is, they have two sets of chromosomes just as sexual species do), but sometimes these females mate with other males, producing offspring which are triploid (that is, they have three sets of chromosomes, or 50% more than equivalent sexual species; see polyploidy
). Over 30% of the Cnemidophorus genus are parthenogenic.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s which belong to the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of Teiidae
Teiidae
Teiidae is a family of lizards native to the Americas, generally known as whiptails. The group includes the parthenogenic genera Cnemidophorus and Aspidoscelis, and the non-parthenogenic Tupinambis. It has over 230 member species in ten genera...
, which are commonly referred to as whiptail lizards or racerunners. Note that the nomenclature
Binomial nomenclature
Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages...
for this genus has recently been re-examined by T. W. Reeder et al. in 2002. Many species that were Cnemidophorus should now likely be considered Aspidoscelis
Aspidoscelis
Aspidoscelis is a genus of whiptail lizards, from the family Teiidae. The nomenclature for this genus has recently been published by T. W. Reeder et al. in 2002...
based upon divergent characters between the two groups.
Parthenogenesis
In some of the Cnemidophorus speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, there are no males, and they reproduce through parthenogenesis
Parthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
. This is well-known in bee
Bee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
s and aphids, but is very rare in vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s. Those species without males are now known to originate through hybridization, or interspecific breeding. Occasionally, a mating between a female of one species and a male of another produces a parthenogen, a female that is able to produce viable eggs that are genetically identical to her own cells. The lizards that hatch from these eggs are thus also parthenogens that can again produce identical eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, resulting in an asexual, clonal
Clonal
Clonal may refer toin Immunology:*Clonal deletion, a process by which B cells and T cells are deactivated before act significantly upon specific antigens*Clonal selection theory, a model for how the immune system responds to infection...
population. Parthenogenetic species resulting from a single hybridization are diploid (that is, they have two sets of chromosomes just as sexual species do), but sometimes these females mate with other males, producing offspring which are triploid (that is, they have three sets of chromosomes, or 50% more than equivalent sexual species; see polyploidy
Polyploidy
Polyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
). Over 30% of the Cnemidophorus genus are parthenogenic.
Species
- Cnemidophorus angusticeps
- Cnemidophorus arenivagus
- Cnemidophorus arizonae
- Cnemidophorus arubensis
- Cnemidophorus burti
- Cnemidophorus calidipes
- Cnemidophorus ceralbensis
- Cnemidophorus communis
- Cnemidophorus costatus
- Cnemidophorus cozumelae
- Cnemidophorus cryptus
- Cnemidophorus deppei
- Cnemidophorus dixoniCnemidophorus dixoniThe Gray Checkered Whiptail is a species of lizard native to the United States in southern New Mexico and western Texas, and northern Mexico. It was once considered a subspecies of the Common Checkered Whiptail, Cnemidophorus tesselatus, but was later granted full species status. It is one of many...
- Cnemidophorus exsanguisCnemidophorus exsanguisThe Chihuahuan Spotted Whiptail is a species of lizard native to the United States in southern Arizona, southern New Mexico and southwestern Texas, and northern Mexico in northern Chihuahua and northern Sonora...
- Cnemidophorus flagellicaudus
- Cnemidophorus gramivagus
- Cnemidophorus gularisCnemidophorus gularisThe Texas spotted whiptail is a species of long-tailed lizard native to the southern United States, in Texas, New Mexico, and Oklahoma, and northern Mexico in Coahuila, Nuevo León, Tamaulipas, San Luis Potosí, Querétaro, and Veracruz.- Description :Texas spotted whiptails grow inches in length...
- Cnemidophorus guttatus
- Cnemidophorus gypsi
- Cnemidophorus hyperythrus
- Cnemidophorus inornatusCnemidophorus inornatusThe Little Striped Whiptail is a species of lizard found in the United States, in Arizona, New Mexico and Texas, and in northern Mexico in Chihuahua, Coahuila, Durango, Zacatecas, San Luis Potosí, and Nuevo León...
- Cnemidophorus labialis
- Cnemidophorus lacertoides
- Cnemidophorus laredoensisCnemidophorus laredoensisThe Laredo Striped Whiptail is a species of lizard found in the southern United States, in Texas, and northern Mexico in Coahuila and Tamaulipas. Some sources believe it to be the result of extensive hybridization between the Eastern Spotted Whiptail, Cnemidophorus gularis and the Six-lined...
- Cnemidophorus leachei
- Cnemidophorus lemniscatus
- Cnemidophorus lineattissimus
- Cnemidophorus littoralis
- Cnemidophorus longicaudus
- Cnemidophorus marmoratusCnemidophorus marmoratusThe Marbled Whiptail is a species of lizard found in the United States, in southern New Mexico and Texas, and in northern Mexico, in Coahuila, Chihuahua and Durango.- Description :...
- Cnemidophorus martyris
- Cnemidophorus maximus
- Cnemidophorus mexicanus
- Cnemidophorus motaguae
- Cnemidophorus mumbuca
- Cnemidophorus murinus
- Cnemidophorus nativo
- Cnemidophorus neomexicanusCnemidophorus neomexicanusThe New Mexico whiptail is a species of lizard found in the southern United States in New Mexico and Arizona, and in northern Mexico in Chihuahua. It is the official state reptile of New Mexico...
- Cnemidophorus neotesselatus
- Cnemidophorus nigricolor
- Cnemidophorus ocellifer
- Cnemidophorus opatae
- Cnemidophorus pai
- Cnemidophorus parecis
- Cnemidophorus parvisocius
- Cnemidophorus pseudolemniscatus
- Cnemidophorus rodecki
- Cnemidophorus sackii
- Cnemidophorus scalaris
- Cnemidophorus septemvittatusCnemidophorus septemvittatusThe Plateau spotted whiptail is a species of lizard found in the southern United States in Texas, and in northern Mexico in Chihuahua and Coahuila...
- Cnemidophorus serranus
- Cnemidophorus sexlineatusCnemidophorus sexlineatusThe Six-lined Racerunner is a species of lizard found in the United States, from Wyoming across the Great Plains east to Rhode Island, south to Florida and west to southern Texas, and in northern Mexico, in Tamaulipas....
- Cnemidophorus sonorae
- Cnemidophorus tesselatusCnemidophorus tesselatusThe Checkered Whiptail is a species of lizard found in the southwestern United States in Colorado, Texas and New Mexico, and in northern Mexico in Chihuahua and Coahuila...
- Cnemidophorus tigrisCnemidophorus tigrisThe western whiptail is a small lizard that ranges throughout most of the southwestern United States. Most of its populations appear stable, and is not listed as endangered in any of the states comprising its range...
- Cnemidophorus uniparensDesert Grassland Whiptail LizardThe Desert Grassland Whiptail lizard is an all-female species. It was formerly placed in the genus Cnemidophorus. These reptiles reproduce by parthenogenesis; eggs undergo a chromosome doubling after meiosis and develop into lizards without being fertilized...
- Cnemidophorus vacariensis
- Cnemidophorus vanzoi
- Cnemidophorus velox