The marbled whiptail (''Aspidoscelis marmoratus'') is a

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), ...

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

found in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, in southern

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

, and in northern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, in

Coahuila Coahuila, formally Coahuila de Zaragoza, officially the Free and Sovereign State of Coahuila de Zaragoza, is one of the 31 states of Mexico. The largest city and State Capital is the city of Saltillo; the second largest is Torreón and the thi ...

, Chihuahua and

Durango Durango, officially the Free and Sovereign State of Durango, is one of the 31 states which make up the Political divisions of Mexico, 32 Federal Entities of Mexico, situated in the northwest portion of the country. With a population of 1,832,650 ...

Description

The marbled whiptail grows from 8 to 12 inches in length. It is grey or black overall in color with 4 to 8 yellow or white stripes, often with dark mottling, giving it a

marble Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or Dolomite (mineral), dolomite (CaMg(CO3)2) that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is ty ...

d appearance. Their underside is white or pale yellow, with a peach coloration on the throat. They are slender bodied, with long

tail The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to los ...

Behavior

Like most other species of whiptail lizards, the marbled whiptail is diurnal and

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant which eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores we ...

. It is wary, energetic, and fast moving, darting for cover if approached. Its preferred

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

is semiarid, sandy areas with sparse vegetation, or the open edges of wooded areas. Breeding takes place in the spring, with up to four

eggs An egg is an organic vessel in which an embryo begins to develop. Egg, EGG or eggs may also refer to: Biology * Egg cell, the female reproductive cell (gamete) in oogamous organisms Food * Eggs as food Places * Egg, Austria * Egg, Switzerland ...

laid sometime between the months of May and August, hatch happening usually in August during the wet season.Gadsden, H., & Castañeda, G. (2013). Life history of the marbled whiptail lizard Aspidoscelis marmorata from the central Chihuahuan Desert, Mexico. Acta Herpetologica, 8(2), 81-91. The eggs hatch in six to eight weeks. A second clutch of eggs is occasionally laid in mid summer. Hatchlings look much like the adults, except they have bright blue colored tails.

Facultative parthenogenesis

Facultative

parthenogenesis 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 ...

can occur in ''A. marmoratus'' haploid unfertilized

oocyte An oocyte (, oöcyte, or ovocyte) is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ger ...

s by a post-meiotic mechanism resulting in

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

wide homo

zygosity Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mos ...

. In many species that are facultatively parthenogenetic, the transition to the completely homozygous condition results in exposure of the

genetic load Genetic load is the difference between the fitness of an average genotype in a population and the fitness of some reference genotype, which may be either the best present in a population, or may be the theoretically optimal genotype. The average ...

leading to embryonic mortality and an elevated rate of

congenital malformations A birth defect is an abnormal condition that is present at birth, regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth de ...

. However, in ''A. marmoratus'' a small percentage of unfertilized oocytes undergo parthenogenesis and yet develop normally. Thus, in this case, facultative parthenogenesis has the potential for allowing

purifying selection In natural selection, negative selection or purifying selection is the selective removal of alleles that are deleterious. This can result in stabilising selection through the purging of deleterious genetic polymorphisms that arise through random ...

to occur with the result that all lethal recessive

allele An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...

s are purged in just one generation.

Subspecies

There are two recognized subspecies of ''A. marmoratus'': *'' Aspidoscelis marmoratus marmoratus'' ( Baird & Girard, 1852) *'' Aspidoscelis marmoratus reticuloriens'' ( Vance, 1978)

References

*
Herps of Texas: ''Cnemidophorus marmoratus''
{{Taxonbar, from=Q2866853 Aspidoscelis Fauna of the Southwestern United States Reptiles of the United States Reptiles of Mexico Reptiles described in 1852 Taxa named by Spencer Fullerton Baird Taxa named by Charles Frédéric Girard