Eumeces

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Eumeces
Young Western Skink (Eumeces skiltonianus)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Reptilia (paraphyletic) (unranked) Sauria Order: Squamata (paraphyletic) Infraorder: Scincomorpha Family: Scincidae Subfamily: see text Genus: Eumeces Wiegmann, 1834
Species
About 40, and see text.

The genus Eumeces are skinks (family Scincidae). They are secretive, agile animals with a cylindrical body covered with smooth, shiny scales.

The genus sometimes goes by the common name of "New World Skinks" or "Great Skinks" (from Ancient Greek - the prefix "eu" means "true" or "good", "mokos" means "size" or "length"), but both these common names are actually misnomers: skinks of the genus Eumeces occur also in Asia, and they're not particularly big either: while the largest skinks of this genus, the Great Plains Skink, can reach a length of some 34 cm or about 14 inches, most species are smaller than 20 cm including the tail. The tail makes up for about half of this total length.

Another colloquial name of these skinks is "blue-tailed skink": young Eumeces often have a brightly colored tail, which is typically blue. In most species, this coloring is lost when the animal reaches adulthood, but a few species retain the color even as adults, e.g. the Bluetail Mole Skink.

[edit] Ecology

The conspicuous coloring is a survival trait: it attracts a predator's attention to the tail of the animal, which will break off when grabbed. A skink thus often manages to escape and hide under some rock, log, or fallen leaves while the predator still contemplates the wildly thrashing severed tail. (This is an instance of what is called autotomy: voluntarily shedding a body part in order to escape.)

The skink regrows an autotomized tail, which then usually has the same color as the rest of the body and typically is also shorter than the original tail. In some species, regrown tails are pinkish. A regrown tail has a cartilaginous rod for support instead of vertebrae.

Eumeces are all oviparous. The female lays eggs once a year after the breeding season in spring. The clutch size varies and is typically around 5 to 10 eggs. The hatchlings appear in late summer.

Like other reptiles, these skinks are "cold-blooded" — they are ectothermic animals: their metabolism cannot regulate their body temperature. To warm up, they often bask in the sun. In colder climates, they hibernate in winter in burrows below the frost line. In hot climates, they are active mainly in the morning and evening, staying under cover during the hottest hours of the day to avoid overheating.

These skinks are not dangerous to humans. They are not especially aggressive, but will bite if provoked. The bite is not very painful, even to children, who may find great amusement with the spectacle of a lizard dangling from their forefinger. Whether the skink finds this experience amusing as well is doubtful. Eumeces are delicate animals whose tail breaks off easily, and herpetologists and other enthusiasts should handle them with great care, if at all.

[edit] Systematics

This genus is usually placed in the subfamily Scincinae which seems to be paraphyletic however. Apparently part of a clade which does not seem to include the type genus Scincus, it will probably be eventually assigned to a new, yet-to-be-named subfamily.(Austin & Arnold 2006)

Within Eumeces, the following species are recognized:

Eumeces anthracinus, Coal Skink Eumeces barbouri, Barbour's Skink (Japan) Eumeces brevirostris, Short-nose Skink (Mexico) Eumeces callicephalus, North American Mountain Skink Eumeces capito Eumeces chinensis, Chinese Skink (East Asia: China, Korea, Japan) Eumeces colimensis (Mexico) Eumeces copei (Mexico) Eumeces coreensis, Korean Skink (Korea) Eumeces dugesii (Mexico) - rare Eumeces egregius, Mole Skink Eumeces elegans, Five-striped Blue-tailed Skink or Shanghai Skink (East Asia) Eumeces fasciatus, Common Five-lined Skink Eumeces gilberti, Gilbert's Skink (North America) Eumeces inexpectatus, Southeastern Five-lined Skink Eumeces kishinouyei, Kishinoue's Giant Skink Eumeces lagunensis, San Lucan Skink Eumeces laticeps, Broad-headed Skink Eumeces latiscutatus, Japanese Skink (Japan) Eumeces liui (Asia)

Eumeces longirostris, Bermuda Rock Skink Eumeces lynxe, Oak Forest Skink (Mexico) Eumeces marginatus, Ryūkyū Five-lined Skink (Okinawa and Amami Islands) Eumeces multilineatus Eumeces multivirgatus, Many-lined Skink Eumeces (multivirgatus) gaigeae, Variable Skink (North America) - sometimes Eumeces (multivirgatus) epipleurotus Eumeces obsoletus, Great Plains Skink Eumeces ochoterenae Eumeces okadae, Okada's Five-lined Skink (Japan) Eumeces parviauriculatus, Northern Pygmy Skink (Mexico) Eumeces parvulus, Southern Pygmy Skink (Mexico) Eumeces popei (Asia) Eumeces quadrilineatus, Four-lined Asian Skink Eumeces septentrionalis, Prairie Skink - includes Eumeces obtusirostris Eumeces skiltonianus, Western Skink Eumeces stimpsonii, Yaeyama Seven-lined Skink (Japan) Eumeces sumichrasti (Mexico) Eumeces tamdaoensis Eumeces tetragrammus, Four-lined Skink Eumeces tunganus

Some species that were formerly considered Eumeces have now been assigned to new genera:

Now in Eurylepis:

• Eumeces indothalensis - now Eurylepis indothalensis
• Eumeces poonaensis - now Eurylepis poonaensis
• Eumeces taeniolatus - now Eurylepis taeniolatus

Now in Mesoscincus:

• Eumeces altamirani - now Mesoscincus altamirani
• Eumeces managuae - now Mesoscincus managuae
• Eumeces schwartzei - now Mesoscincus schwartzei

Now in Novoeumeces:

• Eumeces algeriensis - now Novoeumeces algeriensis
• Eumeces blythianus - now Novoeumeces blythianus
• Eumeces schneideri - now Novoeumeces schneideri

[edit] References

• Austin, J.J. & Arnold, E.N. (2006): Using ancient and recent DNA to explore relationships of extinct and endangered Leiolopisma skinks (Reptilia: Scincidae) in the Mascarene islands. Molecular Phylogenetics and Evolution 39(2): 503–511. doi:10.1016/j.ympev.2005.12.011 (HTML abstract)