''Aspidoscelis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of whiptail lizards in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Teiidae Teiidae is a family of lacertoidean lizards native to the Americas. Members of this family are generally known as whiptails or racerunners; however, tegus also belong to this family. Teiidae is sister to the Gymnophthalmidae, Gymnopthalmidae, and ...

Taxonomy

The

nomenclature Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. (The theoretical field studying nomenclature is sometimes referred to as ''onymology'' or ''taxonymy'' ). The principl ...

for the genus ''Aspidoscelis'' was published by T.W. Reeder et al. in 2002. Many

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

that were formerly included in the genus '' Cnemidophorus'' are now considered ''Aspidoscelis'' based upon divergent characters between the two groups.

Etymology

The name ''Aspidoscelis'' literally means "shield-leg", from the Ancient Greek ("shield") and ("leg").

Species

The following species are recognized as being valid. *'' Aspidoscelis angusticeps'' – Yucatán whiptail *'' Aspidoscelis arizonae'' – Arizona striped whiptail *''

Aspidoscelis burti The canyon spotted whiptail (''Aspidoscelis burti'') is a species of lizard in the family Teiidae. The species is native to northwestern Mexico and the adjacent southwestern United States. Etymology The specific name, ''burti'', is in honor of ...

'' – canyon spotted whiptail *'' Aspidoscelis calidipes'' – Tepalcatepec Valley whiptail *'' Aspidoscelis carmenensis'' – Carmen Island whiptail *''

Aspidoscelis ceralbensis ''Aspidoscelis ceralbensis'', the Cerralvo Island whiptail, is a species of teiid lizard endemic to Jacques Cousteau Island in Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost cou ...

'' – Cerralvo Island whiptail *''

Aspidoscelis communis ''Aspidoscelis communis'', also known as the Colima giant whiptail, is a species of teiid lizard endemic to Mexico. References communis ''Communis'' may refer to: Anatomy * Anulus tendineus communis or annulus of Zinn, a ring of fibrous ...

'' – Colima giant whiptail *''

Aspidoscelis costatus ''Aspidoscelis costatus'', also known as the western Mexico whiptail, is a species of whiptail lizard endemic to Mexico, including Guerrero, Morelos, and Puebla in southern Mexico, as well as other Mexican states. Its range spans both temperate ...

'' – western Mexico whiptail lizard *''

Aspidoscelis cozumela ''Aspidoscelis cozumela'', the Cozumel racerunner, is a species of teiid lizard endemic to Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders th ...

'' – Cozumel racerunner *''

Aspidoscelis danheimae ''Aspidoscelis danheimae'', also known commonly as the Isla San José whiptail, the San Jose Island blue-throated whiptail, and ''el huico de la Isla San José'' in Spanish, is a species of lizard in the family Teiidae. The species is endemic to ...

'' – Isla San José whiptail *'' Aspidoscelis deppii'' – blackbelly racerunner *'' Aspidoscelis dixoni'' – gray checkered whiptail *'' Aspidoscelis espiritensis'' – Espiritu Santo whiptail *'' Aspidoscelis exsanguis'' – Chihuahuan spotted whiptail *'' Aspidoscelis franciscensis'' – San Francisco Island whiptail *'' Aspidoscelis gularis'' – Texas spotted whiptail *'' Aspidoscelis guttatus'' – Mexican racerunner *'' Aspidoscelis hyperythrus'' – orange-throated whiptail *'' Aspidoscelis inornatus'' – little striped whiptail *'' Aspidoscelis labialis'' – Baja California whiptail *'' Aspidoscelis laredoensis'' – Laredo striped whiptail *'' Aspidoscelis lineattissimus'' – many-lined whiptail *'' Aspidoscelis marmoratus'' – marbled whiptail *'' Aspidoscelis martyris'' – San Pedro Martir whiptail *'' Aspidoscelis maslini'' – Maslin's whiptail *'' Aspidoscelis maximus'' – Cape Region whiptail *'' Aspidoscelis mexicanus'' – Mexican whiptail *'' Aspidoscelis motaguae'' – giant whiptail *'' Aspidoscelis neomexicanus'' – New Mexico whiptail *'' Aspidoscelis neotesselatus'' – Colorado checkered whiptail, triploid checkered whiptail *'' Aspidoscelis opatae'' – Opata whiptail *'' Aspidoscelis pai'' – Pai striped whiptail *'' Aspidoscelis parvisocius'' – Mexican pigmy whiptail *'' Aspidoscelis pictus'' – Isla Monserrate whiptail *'' Aspidoscelis preopatae'' *'' Aspidoscelis rodecki'' – Rodeck's whiptail *'' Aspidoscelis sackii'' – Sack's spotted whiptail *'' Aspidoscelis scalaris'' – rusty-rumped whiptail *'' Aspidoscelis septemvittatus'' – plateau spotted whiptail *'' Aspidoscelis sexlineatus'' – six-lined racerunner *'' Aspidoscelis sonorae'' – Sonoran spotted whiptail *'' Aspidoscelis stictogrammus'' – giant spotted whiptail *'' Aspidoscelis tesselatus'' – common checkered whiptail *'' Aspidoscelis tigris'' – western whiptail *'' Aspidoscelis uniparens'' – desert grassland whiptail lizard *'' Aspidoscelis velox'' – plateau striped whiptail *'' Aspidoscelis xanthonotus'' – red-backed whiptail ''

Nota bene ( ; plural: ) is the Latin language, Latin phrase meaning ''note well''. In manuscripts, ''nota bene'' is abbreviated in upper-case as NB and N.B., and in lower-case as n.b. and nb; the editorial usages of ''nota bene'' and ''notate bene'' fi ...

'': A binomial authority in parentheses indicates that the species was originally described in a genus other than ''Aspidoscelis''.

Speciation

In 2011, it was announced that a

parthenogenetic Parthenogenesis (; from the Greek + ) is a natural form of asexual reproduction in which the embryo develops directly from an egg without need for fertilization. In animals, parthenogenesis means the development of an embryo from an unfertiliz ...

hybrid ''Aspidocelis'' was bred in the laboratory. This serves as a demonstration of how other hybrid parthenogens in this genus may have arisen.

Parthenogenesis and unisexual species

Thirteen species within Aspidoscelis are unisexual, consisting entirely of females that reproduce through parthenogenesis—cloning unfertilized eggs to produce genetically identical offspring.These species originated through hybridization between divergent bisexual ancestral species, with the transition to asexual reproduction occurring in a single generation. This represents the largest group of unisexual vertebrate species known to science. The unisexual species exhibit varying chromosome numbers reflecting their hybrid origins. Diploid species formed through "primary hybrid speciation" when first-generation female hybrids of two distinct bisexual species began reproducing parthenogenetically. Triploid and tetraploid species arose through "genome addition," when cloned eggs of unisexual females were fertilized by males of bisexual species, resulting in offspring with additional chromosome sets. This hybridization seesm separated by 15–25 million years of evolution. The parental species combinations have been determined through karyotypic, allozyme, and mitochondrial DNA studies. Early chromosome studies in the 1960s first revealed abnormal chromosome numbers in some unisexual species, indicating genome combinations from divergent species through hybridization. The unisexual species occur in two main geographic regions: the southwestern United States and northern Mexico, and southern Mexico with eastern Guatemala and Belize. Recent cellular research has revealed that chromosome number and genetic diversity are maintained across generations because identical, duplicated chromosomes pair during meiosis rather than homologous chromosomes.

References

External links

* Reeder, Tod W.; Cole, Charles J.; Dessauer, Herbert C. (2002). "Phylogenetic relationships of whiptail lizards of the genus ''Cnemidophorus'' (Squamata, Teiidae) : a test of monophyly, reevaluation of karyotypic evolution, and review of hybrid origins". ''American Museum Novitates'' (3365): 1-61

Aspidoscelis, Lizard genera Taxa named by Leopold Fitzinger {{Teiidae-stub