Coral snake

Coral Snakes
Coral snake (Micrurus sp.)
Coral snake (Micrurus sp.)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Order: Squamata
Suborder: Serpentes
Family: Elapidae
Genus: Leptomicrurus
Calliophis
Micrurus
Micruroides
Species

See text.

The coral snakes are a large group of elapid snakes that can be divided into two distinct groups: New World coral snakes and Old World Calliophis snakes. There are three genera among New World coral snakes that consist of over 65 recognized species.

Coral snakes are most notable for their red, yellow/white, and black colored banding. (Several nonvenomous species have similar coloration, however, including the Scarlet Kingsnake, the Milk Snake, and the Chionactis occipitalis annulata). In some regions, the order of the bands distinguishes between the non-venomous mimics and the venomous coral snakes, inspiring some folk rhymes — "Red and yellow, kill a fellow; red and black, friendly jack", and "Red and yellow, kill a fellow; red and black, venom lack" However, this only reliably applies to coral snakes native to North America: Micrurus fulvius (Eastern or common), Micrurus tener (Texas), and Micruroides euryxanthus (Arizona), found in the southern and eastern United States. Coral snakes found in other parts of the world can have distinctly different patterns, have red bands touching black bands, have only pink and blue banding, or have no banding at all.

Most species of coral snake are small in size. North American species average around 3 feet (91 cm) in length, but specimens of up to 5 feet (150 cm) or slightly larger have been reported. Aquatic species have flattened tails, to act as a fin, aiding in swimming.

Contents

Behavior

Coral snake showing typically reclusive behavior of hiding under rotting wood. This one was over 30 inches long, but less than an inch across.

Coral snakes vary widely in their behavior, but most are very elusive, fossorial snakes which spend the vast majority of their time buried in the ground or in the leaf litter of a rainforest floor, only coming to the surface during rains or during breeding season. Some species, like Micrurus surinamensis are almost entirely aquatic and spend most of their lives in slow-moving bodies of water that have dense vegetation.

Like all elapid snakes, coral snakes use a pair of small fangs, which are fixed in the front of their top jaw, to deliver their venom. Due to the time it takes for the venom to take effect, coral snakes have a tendency to hold on to a victim when biting, unlike vipers which have retractable fangs and tend to prefer to strike and let go immediately. Coral snakes are not aggressive or prone to biting however, and account for less than one percent of the number of snake bites each year in the United States. Most coral snake bites occur because of accidental handling of the snake while engaged in an activity like gardening.

Distribution

Distribution in the United States.
Eastern Coral Snake, Micrurus fulvius

New World coral snakes exist in the southern range of many temperate U.S. states.

The eastern coral snake is found in scattered localities in the southern Coastal Plain from North Carolina to Louisiana , including all of Florida , where they are most prevalent. They can be found in pine and scrub oak sandhills habitats in parts of their range but sometimes inhabit hardwood areas and pine flatwoods that undergo seasonal flooding.[1]

There is controversy about the classification of the very similar Texas coral snake as a separate species. Its habitat, in Texas, Louisiana, and Arkansas, is separated from the eastern habitat by the Mississippi River.[2]

The Arizona coral snake, clearly a separate species, is found in central and southern Arizona, extreme southwestern New Mexico and southward to Sinaloa in western Mexico. It occupies arid and semiarid regions in many different habitat types including thornscrub, desert-scrub, woodland, grassland and farmland. It is found in the plains and lower mountain slopes from sea level to 5800 feet (1768 m); often found in rocky areas. [3]

Danger to humans

New World coral snakes possess the second most potent venom of any North American snake, behind some rattlesnake species. However, few bites are recorded due to their reclusive nature and the fact they generally inhabit sparsely populated areas. When confronted by humans, coral snakes will almost always attempt to flee, and bite only as a last resort. In addition, coral snakes have short fangs (proteroglyph dentition) that cannot penetrate thick leather clothing. Any skin penetration, however, is a medical emergency that requires immediate attention. Coral snakes have a powerful neurotoxin that paralyzes the breathing muscles; mechanical or artificial respiration, along with large doses of antivenom, are often required to save a victim's life. There is usually only mild pain associated with a bite, but breathing difficulties and ptosis can occur within hours.

Treatment of U.S. Coral Snakebite

Texas coral snake, Micrurus tener

The sole manufacturer of Eastern and Texas Coral Snake Antivenom, Wyeth, has ceased production of this product and it is estimated that all remaining in-date stocks of Coral Snake Antivenom in the United States will be exhausted between October and December, 2008. Unless the U.S. Food and Drug Administration approves a new or foreign (Mexican) antivenom currently being tested at the Natural Toxins Research Center (Texas A&M University-Kingsville) then U.S. victims of Eastern and Texas Coral Snake envenomation will no longer be able to be treated by antivenom. The consequences of this radically changes the way Coral Snake envenomation is treated.

Victims of Eastern and Texas Coral snakebite should be transported as soon as possible to a tertiary level hospital which can provide constant monitoring of neurological and respiratory symptoms for 24 hours or more and if these symptoms occur be ready and able to sedate, endotracheally intubate and mechanically ventilate such patients for up to a week or until neurological and respiratory paralysis resolves. To the list of neurological symptoms patients must also be evaluated by serial (and frequent) testing of NIF (Negative Inspiratory Force) and arterial blood gases. The most dangerous sequelae of Texan or Eastern Coral Snakebite is bulbar respiratory paralysis. Fortunately, this does not occur for anywhere from several hours to as long as 24 hours after being bitten, which provides sufficient time to transport and evaluate such patients. However, the fact that the worst effects of this snakebite take so long to occur means that such patients must be kept under conditions involving continuous eyes-on monitoring of ECG, blood pressure, as well as respiratory evaluation for at least two days after being bitten. Some centers may want to consider the elective sedation, intubation and mechanical ventilation of such cases as acting on the side of caution.[4]

Taxonomy

Old World

Genus Calliophis

Main article: Calliophis

New World

Genus Leptomicrurus

  • Leptomicrurus collaris collaris (Schlegel, 1837)
  • Leptomicrurus collaris breviventris (Roze & Bernal-Carlo, 1987)
  • Leptomicrurus narduccii narduccii (Jan, 1863)
  • Leptomicrurus narduccii melanotus (Peters, 1881)

Genus Micruroides

  • Micruroides euryxanthus australis (Zweifel & Norris, 1955)
  • Micruroides euryxanthus euryxanthus (Kennicott, 1860)
  • Micruroides euryxanthus neglectus (Roze, 1967)

Genus Micrurus

  • Micrurus alleni alleni (Schmidt, 1936)
  • Micrurus alleni richardi (Taylor, 1951)
  • Micrurus alleni yatesi (Taylor, 1954)
  • Micrurus ancoralis jani (Schmidt, 1936)
  • Micrurus ancoralis ancoralis (Jan, 1872)
  • Micrurus annellatus annellatus (Peters, 1871)
  • Micrurus annellatus balzanii (Boulenger, 1898)
  • Micrurus annellatus bolivianus (Roze, 1967)
  • Micrurus browni browni (Schmidt & Smith, 1943)
  • Micrurus browni importunus (Roze, 1967)
  • Micrurus browni Taylori (Schmidt & Smith, 1943)
  • Micrurus diastema diastema (Duméril, Bibron, & Duméril, 1854)
  • Micrurus diastema aglaeope (Cope, 1859)
  • Micrurus diastema alienus (Werner, 1903)
  • Micrurus diastema affinis (Jan, 1858)
  • Micrurus diastema apiatus (Jan, 1858)
  • Micrurus diastema macdougalli (Roze, 1967)
  • Micrurus diastema sapperi (Werner, 1903)
  • Micrurus dissoleucus dissoleucus (Cope, 1860)
  • Micrurus dissoleucus dunni (Barbour, 1923)
  • Micrurus dissoleucus melanogenys (Cope, 1860)
  • Micrurus dissoleucus meridensis (Roze, 1989)
  • Micrurus dissoleucus nigrirostris (Schmidt, 1955)
  • Micrurus distans distans (Kennicott, 1860)
  • Micrurus distans michoacanensis (Duges, 1891)
  • Micrurus distans oliveri (Roze, 1967)
  • Micrurus distans zweifeli (Roze, 1967)
  • Micrurus dumerili antioquiensis (Schmidt, 1936)
  • Micrurus dumerili carinicaudus (Schmidt, 1936)
  • Micrurus carinicauda (Schmidt, 1936)
  • Micrurus dumerili colombianus (Griffin, 1916)
  • Micrurus dumerili transandinus (Schmidt, 1936)
  • Micrurus dumerili venezuelensis (Roze, 1989)
  • Micrurus elegans elegans (Jan, 1858)
  • Micrurus elegans veraepacis (Schmidt, 1933)
  • Micrurus ephippifer zapotecus (Roze, 1989)
  • Micrurus ephippifer ephippifer (Cope, 1886)
  • Micrurus filiformis filiformis (Günther, 1859)
  • Micrurus filiformis subtilis (Roze, 1967)
  • Micrurus frontalis frontalis (Duméril, Bibron, & Duméril, 1854)
  • Micrurus frontalis brasiliensis (Roze, 1967)
  • Micrurus frontalis mesopotamicus (Barrio & Miranda 1967)
  • Micrurus hemprichii hemprichii (Jan, 1858)
  • Micrurus hemprichii ortoni (Schmidt, 1953)
  • Micrurus hemprichii rondonianus (Roze & Da Silva, 1990)
  • Micrurus langsdorffi langsdorffi (Wagler, 1824)
  • Micrurus langsdorffi ornatissimus (Jan, 1858)
  • Micrurus laticollaris laticollaris (Peters, 1870)
  • Micrurus laticollaris maculirostris (Roze, 1967)
  • Micrurus lemniscatus lemniscatus (Linnaeus, 1758)
  • Micrurus lemniscatus carvalhoi (Roze, 1967)
  • Micrurus lemniscatus diutius (Burger, 1955)
  • Micrurus lemniscatus frontifasciatus (Werner, 1927)
  • Micrurus lemniscatus helleri (Schmidt & Schmidt, 1925)
  • Micrurus limbatus limbatus (Fraser, 1964)
  • Micrurus limbatus spilosomus (Perez-Higaredo & Smith, 1990)
  • Micrurus mipartitus mipartitus (Duméril, Bibron, & Duméril, 1854)
  • Micrurus mipartitus anomalus (Boulenger, 1896)
  • Micrurus mipartitus decussatus (Duméril, Bibron, & Duméril, 1854)
  • Micrurus mipartitus semipartitus (Jan, 1858)
  • Micrurus multifasciatus multifasciatus (Jan, 1858)
  • Micrurus multifasciatus hertwigi (Werner, 1897)
  • Micrurus nigrocinctus babaspul (Roze, 1967)
  • Micrurus nigrocinctus coibensis (Schmidt, 1936)
  • Micrurus nigrocinctus divaricatus (Hallowell, 1855)
  • Micrurus nigrocinctus mosquitensis (Schmidt, 1933)
  • Micrurus nigrocinctus nigrocinctus (Girard, 1854)
  • Micrurus nigrocinctus ovandoensis (Schmidt & Smith, 1943)
  • Micrurus nigrocinctus wagneri (Mertens, 1941)
  • Micrurus nigrocinctus yatesi (Dunn, 1942)
  • Micrurus nigrocinctus zunilensis (Schmidt, 1932)
  • Micrurus psyches circinalis (Duméril, Bibron & Duméril, 1854)
  • Micrurus psyches donosoi (Hoge, Cordeiro, & Romano, 1976)
  • Micrurus psyches psyches (Daudin, 1803)
  • Micrurus spixii spixii (Wagler, 1824)
  • Micrurus spixiii martiusi (Schmidt, 1953)
  • Micrurus spixii obscurus (Jan, 1872)
  • Micrurus spixii princeps (Boulenger, 1905)
  • Micrurus steindachneri steindachneri (Werner, 1901)
  • Micrurus steindachneri orcesi (Roze, 1967)
  • Micrurus surinamensis surinamensis (Cuvier, 1817)
  • Micrurus surinamensis nattereri (Schmidt, 1952)
  • Micrurus tener fitzingeri (Jan, 1858)
  • Micrurus tener maculatus (Roze, 1967)
  • Micrurus tener microgalbineus (Brown, & Smith, 1942)
  • Micrurus tener tener (Baird, & Girard, 1853)
  • Micrurus tschudii olssoni (Schmidt & Schmidt, 1925)
  • Micrurus tschudii tschudii (Jan, 1858)

Mimicry

New World coral snakes are known to mimic False coral snakes, snake species whose venom is less toxic. This is a rare example of Mertensian mimicry. Species of false coral snake include:

Notes

  1. ↑ University of Georgia, Savannah River Ecology, Snakes of Georgia and South Carolina
  2. ↑ Western Connecticut State University
  3. ↑ Arizona-Sonora Desert Museum
  4. ↑ Added/Updated September 7, 2008 by Steve Grenard, RRT. Moderator of the Venomlist

External links