Drymobius margaritiferus | |
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Drymobius margaritiferus, Tamaulipas, Mexico | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Serpentes |
Family: | Colubridae |
Genus: | Drymobius |
Species: | D. margaritiferus |
Binomial name | |
Drymobius margaritiferus (Schlegel, 1837) | |
Synonyms | |
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Drymobius margaritiferus, commonly known as the speckled racer, is a species of nonvenomous colubrid snake native to the Americas. The specific name, margaritiferus, means "pearl-bearing" in Latin, referring to the pearl-like spots on the dorsal scales.
This species ranges throughout Central America from the Isthmus of Tehuantepec and Yucatán Peninsula, southward to Panama and adjacent areas of northwest Colombia, occurring at elevations from sea level up to 4,750 feet (1,453 m). Northward, it is found in the coastal lowlands and lower exterior slopes of the Sierra Madres of Mexico, up the west coast to Sonora, and up the east coast to northern Tamaulipas. The northern limit of its distribution ranges into extreme south Texas, USA, where it is uncommon to rare in a few of the southernmost counties of the state. [3] [4] [5]
Speckled racers occur in a wide variety of habitats, including: forest, forest edges and clearings, secondary growth, riparian zones, savannahs, marshlands, pastures, and roadsides. [3] [6] It is often said to favor humid and wet areas with permanent water sources. [7] [3] [8] However, these snakes have been found in areas where no water was apparent, and habitats include tropical dry forests and tropical arid forests. [9] [10] [11] In Costa Rica, it is described as "ubiquitous in all but the most humid lowland and pre-montane zones," including dry lowland forests. [6]
The speckled racer is typically black in color, with distinctive yellow and blue spotting, and one light-colored spot on each scale, [12] which gives the snake an overall greenish hue. The labials are yellow, with black sutures. [2] The underside is typically yellow to green. They average 30–40 in. (76–102 cm) in length, with a record specimen documented at 50 in. (127 cm). [7]
The dorsal scales, which are feebly keeled middorsally, but smooth on the flanks, are arranged in 17 rows. The ventrals number 142–168; the subcaudals, 85–126. [13]
As the name "racer" implies, it is a fast and agile species that is predominantly diurnal. [8] It has been described as a nervous species, and will not hesitate to bite in self-defense when restrained or handled. [3] [12] Death feigning behavior, or thanatosis, was reported for two out of seven (28.5%) specimens that were caught and handled during field surveys conducted in Tamaulipas, Mexico. [10]
They will consume a wide variety of prey, but primarily feed on frogs and toads. [7] One study of 36 Guatemalan and Mexican specimens with food items in their stomachs found 86% had anurans (predominantly Eleutherodactylus ), 8% lizards, 4% reptile eggs, and 2% small mammals. [14] Juveniles are known to eat insects. [6]
They are oviparous, typically laying eggs in the spring, although in southern areas, the species is known to deposit eggs as early as February and March. Clutch sizes range from two to eight eggs that are usually 1.5 inches (3.8 cm) in length. Incubation is typically eight to nine weeks, with hatchlings measuring 6 to 10½ inches (15.2–27.6 cm) long. [3]
There are four recognized subspecies of D. margaritiferus:
The speckled racer is a threatened species in the state of Texas, USA, where it is uncommon to rare. [17] In some regions of Mexico and Central America, it is a common species. [3] [6]
The milk snake or milksnake, is a species of kingsnake; 24 subspecies are currently recognized. Lampropeltis elapsoides, the scarlet kingsnake, was formerly classified as a 25th subspecies, but is now recognized as a distinct species. The subspecies have strikingly different appearances, and many of them have their own common names. Some authorities suggest that this species could be split into several separate species. They are not venomous to humans.
The greater earless lizard is the only species in the monotypic genus Cophosaurus. It is closely related to the smaller, lesser earless lizards and other species in the genus Holbrookia, and in fact was placed in that genus and referred to Holbrookia texana from 1852 into the 1970s. Earless lizards lack external ear openings, an adaptation to burrowing in the sand, as are the recessed lower jaw and flared upper labial scales. Greater earless lizards are sexually dimorphic, males grow larger and are more colorful than females, exhibiting pink and green colors that are particularly bright in the breeding season. Two bold black bars mark the lateral region of males but are greatly reduced and vague, or occasionally entirely absent in females.
Mastigodryas boddaerti, commonly known as Boddaert's tropical racer, is a species of snake in the family Colubridae. The species is native to tropical South America including Trinidad and Tobago.
Bothriechis schlegelii, known commonly as the eyelash viper, is a species of venomous pit viper in the family Viperidae. The species is native to Central and South America. Small and arboreal, this species is characterized by a wide array of color variations, as well as the superciliary scales above the eyes. It is the most common of the green palm-pitvipers, and is often present in zoological exhibits. The specific name schlegelii honors Hermann Schlegel, who was a German ornithologist and herpetologist. For other common names see below. No subspecies are currently recognized as being valid.
Terciopelo is a highly venomous species of pit viper found at low to moderate elevations in northeast Mexico and Central America, and into South America where it is known from elevations up to 2600 meters in the Colombian and Ecuadorian Andes, as well as into Venezuela. With a mass of up to 6 kilograms (13 lb) and a maximal length of 2.5 metres (8.2 ft), the terciopelo is among the largest pit vipers. It is light to dark brown in color, often with yellow zig-zag-shaped lines on each side of the body. Dubbed "the ultimate pit-viper" for its large size, fangs and venom yield, it has a fearsome reputation, responsible for the most snakebites within its range because of its defensive temperament and proximity to human residence. However, like other venomous snakes, it avoids confrontation with humans whenever possible. No subspecies are currently recognized.
Agkistrodon taylori is a species of venomous snake, a pitviper (Crotalinae) found only in northeastern Mexico. The standardized names are Taylor's cantil (English) and Metapil (Spanish), although it is sometimes called the ornate cantil as well as several other colloquial names. It was named in honor of American herpetologist Edward Harrison Taylor.
Drymobius is a genus of colubrid snakes commonly referred to as neotropical racers, which are endemic to the Americas. There are four species recognized in the genus.
The eastern racer, or North American racer, is a species of nonvenomous snake in the family Colubridae. The species is endemic to North America and Central America. Eleven subspecies, including the nominotypical subspecies, are recognized, which as a group are commonly referred to as the eastern racers. The species is monotypic in the genus Coluber.
The northern sheep frog is native to Central America, Mexico, and extreme south Texas, United States. It occurs in the lowlands from Sonora, Mexico, to northern Costa Rica on the Pacific coast, and south Texas to Honduras on the Gulf of Mexico and Caribbean coasts. The sheep frog inhabits semiarid thornscrub, savannas, pasturelands, and open woodlands, as well as more humid, moist forest in the canyons, basins, foothills, and lower elevations of mountains slopes. It is a fossorial, burrowing frog that is seldom seen on the surface except at night after heavy rains when they emerge to breed. The sheep frog gets its name from its distinctive call that resembles a sheep's bleat. It is a diet specialist primarily feeding on termites and ants.
The speckled kingsnake is a species of nonvenomous kingsnake in the family Colubridae. The species is endemic to the United States.
Ficimia streckeri, also commonly known as the Mexican hooknose snake, the Tamaulipan hooknose snake, and the Texas hook-nosed snake, is a small species of snake in the family Colubridae. The species is native to northeastern Mexico and adjacent southern Texas.
The Veracruz moist forests is a tropical moist broadleaf forests ecoregion in eastern Mexico.
Porthidium dunni is a species of venomous pitviper in the family Viperidae. The species is endemic to Mexico. There are no recognized subspecies.
Ctenosaura similis, commonly known as the black iguana or black spiny-tailed iguana, is an iguanid lizard native to Mexico and Central America. It has been reported in some Colombian islands in the Caribbean Sea and Pacific Ocean, and has been introduced to the United States in the state of Florida. The largest species in the genus Ctenosaura, it is commonly found in areas such as grasslands and forests.
Agkistrodon howardgloydi is a species of venomous snake, a pit viper (Crotalinae), that is endemic to Central America. It is most commonly called castellana,but it has also been called the southern cantil, Gloyd's moccasin, and a number of other colloquial names. It is a rare species with a relatively small geographic distribution in the tropical dry forest on the Pacific coast of Honduras, Nicaragua, and extreme northwest Costa Rica. Agkistrodon howardgloydi is a stout, medium-sized snake with a maximum length of 96 cm. It is a viviparous species, with female giving birth in the rainy season from May to August. No clinical reports on envenomation had been published, but laboratory texts and analysis indicate the venom is highly toxic and similar to its close relative Agkistrodon bilineatus, and potentially lethal.
Ctenosaura acanthura, is a species of iguanid lizard found in eastern Mexico and extreme western Guatemala. The standardized English name is the Mexican spiny-tailed iguana. Confusingly however, an earlier edition of standardized names for Mexican herpetofauna called Ctenosaura acanthura the northeastern spinytailed iguana and applied the name Mexican spinytailed iguana to Ctenosaura pectinata, which was called the western spiny-tailed iguana in the second edition. It has also been referred to as the Veracruz spiny-tailed iguana and Gulf Coast spiny-tailed iguana. It is an egg laying species that is mostly herbivorous and a moderately large lizard commonly growing over one meter in total length.
The bullsnake is a large, nonvenomous, colubrid snake. It is a subspecies of the gopher snake. The bullsnake is one of the largest/longest snakes of North America and the United States, reaching lengths up to 8 ft.
The El Cielo Biosphere Reserve is located in the Sierra Madre Oriental in the southern part of the Mexican state of Tamaulipas near the town of Gómez Farias. The reserve protects the northernmost extension of tropical forest and cloud forest in Mexico. It has an area of 144,530 hectares made up mostly of steep mountains rising from about 200 metres (660 ft) to a maximum altitude of more than 2,300 metres (7,500 ft).
Salvadora grahamiae, also known commonly as the eastern patch-nosed snake and the mountain patchnose snake, is a species of snake in the family Colubridae. The species is native to the southwestern United States and adjacent northeastern Mexico.