Giant Centipedes in Texas 66

— This article by Jerry Cates et al., first published in September 2002, was last revised on 6 June 2014. © Bugsinthenews Vol. 03:09.

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The giant centipede (Scolopendra heros), also called the giant desert or giant red-headed centipede, is found throughout the southern U.S., particularly in desert regions. It is described in the literature as reaching a maximum length of six to nine inches (15-22 centimeters). Specimens collected in Texas often measure toward the high end of this scale.

The family name, Scolopendridae (from the Greek σκολως “skolos” = “pointed stake, thorn, prickle…”), was first described in 1844 by the U.S. geologist, physician, explorer and author John Strong Newberry (1822-1892). The genus Scolopendra had earlier been described — in 1758 — by the Swedish botanist, zoologist, and taxonomist Carl Linneaus (1707-1778). Finally, the specific name, Scolopendra heros, was later described — in 1853 — by the French biologist Charles Frederic Girard (1822-1895), who besides being born the same year as Newberry, was for a time his close colleague and fellow member of the Megatherium Club at the Smithsonian.

This species of centipede has powerful jaws —  modified front legs, termed maxillipeds — and its venom is known to produce significant pain and swelling that, when combined with infectious organisms acquired in its travels and feeding (this centipede is known to feed on putrefying flesh and fecal matter, and thus is subject to microbial contamination), can produce serious complications. Their bites should, therefore, be considered at least nominally dangerous. It has a cluster of simple eyes (ocelli) on either side of the anterior head. These primitive eye clusters apparently provide no assistance in hunting, as the animal hunts nocturnally and , and are not necessary for the animal to respond to light. When the eyes are covered with opaque paint, no difference is noted in its immediate negative response to bright light stimulus.

Scolopendra heros has six cephalic segments, which are closely fused in the adult, but observable under magnification in the embryo.  A segmented antennae is attached to the anterior portion of the second cephalic segment. This structure is the animal’s primary sensory organ, and is extensively used when hunting for food.

Wherever these animals are found, they favor a habitat that includes an area of moist litter, such as leaves, decaying vegetable matter, and the like. If your home or apartment is troubled with sightings of centipedes, look for small areas of such litter near the foundation of the building, and either remove them yourself or have the property landscaping personnel remove them to reduce the populations of organisms that favor such habitats.

It has 21-23 body segments, consisting of sclerotized tergal plates dorsally, and sternal plates ventrally, which are connected laterally by softer pleural membranes from which erupt the coxal segments of each leg, and on which are found (on some segments, but not on all) open spiracles for respiration. A single pair of legs, each with seven segments (coxa, trochanter, femur, tibia, and 3 tarsi) is attached to each body segment, save the first and last segments. Legs attached to the first body segment are modified into a pair of four-segmented poisonous jaws. The last body segment comprises the anus of the male, and in the female is further modified into a gonopod with a pair of diminutive, articulating ovipositors.  The posterior pair of legs is the longest and most robust, and is modified for grasping.

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Scolopendridae: giant centepide (Scolopendra heros); body; Linda R., Leakey, TX—24 Apr 2010

CASE 04242010 LINDA, LEAKEY, TEXAS

Linda wrote:

We just found a centipede almost 5 inches long inside the door of our home in Leakey, TX.

Is this a giant Texas centipede? What can you tell me about it?

It has a red head, dark body, yellow legs, and blue tail/pinchers.

I took pictures if that will help. We are fairly new to this area and have small grandchildren visiting. Thanks.

This centipede measured some 4.75 inches from head to the tip of its terminal segment. The proximal segments of the terminal pair of prehensile appendages were bluish, grading to yellowish distally to the last tarsal segment, which was darkened.

Scolopendridae: giant redheaded centipede (Scolopendra heros); head; Linda R , Leakey, TX—24 April 2010

Scolopendridae: giant redheaded centipede (Scolopendra heros); posterior; Linda R , Leakey, TX—24 April 2010

The cluster of simple eyes on the right side of Linda’s specimen are visible near the base of the right antenna. The eye cluster shows as a darkened oval slightly depressed into the surface of the head.

The first body segment appears, dorsally, as a narrow bulge just behind the head, and seems to form the forward edge of the second body segment.

Ventrally the first body segment is the base for a pair of large poison jaws, the maxillipeds.

The lateral aspect of the right maxilliped can be seen in the photo, curving around the lower head.

The second body segment forms a broader, reddish collar that extends backward to the first darkened body segment (#3, if you are counting).

Scolopendridae: giant centipede (Scolopendra heros); posterior half; Linda R., Leakey, TX–24 April 2010

Scolopendridae: giant centipede (Scolopendra heros); anterior half; Linda R., Leakey, TX–24 April 2010

This darkened segment still retains some of the reddish hue of the anterior portion of the animal, but beginning with segment 4, just behind it, the dorsal plates (tergites) are uniformly dark.

Segment 4 is relatively long (in the longitudinal aspect of the animal) because it houses the first pair of body spiracles, just posterior to the coxae of the legs of that segment.

From this point through the remainder of the animal’s body, the segments generally alternate between long and short, depending on whether they are provided with spiracles. Notice that segment 5 is short, followed by a longer segment 6, a short segment 7, and a longer segment 8. Segment 9 is the same length as segment 8, as — breaking the pattern — both are fitted with spiracles. Segment 10 is slightly shorter, followed by a remarkably longer segment 11, and a remarkably shorter segment 12 (whose left leg extends upward, in these photos, much further than the other legs on that side of the body).

The photo of the posterior segments shows the diminutive anal segment, showing as a light brown projection beyond the last dark tergite. A pair of bright blue terminal legs, with yellow tarsi divided into three segments (the final one, annotated as T1, being dark brown), emerge from the underside of the last dark segment.

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Scolopendridae: giant centipede (Scolopendra heros); head and anterior body; Temple, TX–02 Aug 2002

CASE 07-092002 KEITH R., NEAR TEMPLE, TEXAS:

The sturdy fellow shown in these pages was kindly collected for me by Kieth R., a friend whose home was at the time ensconced on the shores of a large lake near Temple, Texas. That home was being pestered by centipedes, and I studied this specimen for several months to learn more about its habits. It grew to 8 inches in length within the first few months, feeding on crickets supplied by a local pet store. It died, apparently from natural causes, eight months into the study, but not before wreaking havoc upon the other organisms with whom it shared its enclosure. The photos provided here are from an old file, and are not of excellent quality, but are sufficient to display the features discussed.

These photos were taken shortly after the centipede was introduced to his or her new home (the sex was never determined, though the lack of ovipositing structures on the terminal segment suggests it is a male).

That new home was a terrarium in my lab in Round Rock, containing a floor of coarse bark chips, a large, flat, sunning rock, a hollow driftwood log, and a small pool of drinking and bathing water. Four snakes occupied the same enclosure, and they all seemed- at first- to get along fine.

A second centipede was introduced several weeks later, but was soon killed and partially eaten by another inhabitant of the enclosure (parts of the centipede’s body were found in one corner of the enclosure).

I did not witness this centipede’s death, so can only speculate on the perpetrator. However, I was led — after some analysis — to suspect the first centipede as the culprit. Later, this same centipede killed three of the snakes in the enclosure in quick succession.

Scolopendridae: giant centipede (Scolopendra heros); dorsum, with lined snake; Temple TX—02 Aug 2002

The first thing this centipede did after being placed in the terrarium was explore every square inch of the enclosure.

Its meanderings were confined to the lower levels only, however, as its legs terminate in sharply pointed tarsi, which render it entirely unable to negotiate smooth vertical glass spanning more than eight inches.

Note that the animal was quite capable of scaling heights as high as the length of its body, using the last pair of legs as a brace to push the rest of the body upward its full length, especially in corners of the enclosure.

That it could not scale smooth surfaces was, of course, a blessing. Still, I had to make sure it was kept in an enclosure whose sides were higher than its body was long.

The top of a sufficiently deep enclosure can generally be left ajar while caring for its other inhabitants without worrying that the centipede will slip out unnoticed. Sometimes, though, the centipede would climb to the top of the driftwood stump in the enclosure, and was able, from that vantage point, to reach the screen-covered lid. There it would explore for a way out for hours.

Giant Centipede (Scolopendra heros), Temple. Texas–ventral midbody

For a seemingly complicated, primitive body, the centipede moved very fast (some anatomists refer to its walking legs, for this reason, as “running legs”). You might think that a creature with more than 40 legs, enervated by a primitive nervous system, would be clumsy. But they didn’t hold this centipede down. It zipped around the enclosure at a rapid pace.

The centipede’s body is divided into 21 flat segments. Three of these are colored a caramel brown and are right behind the head. The other eighteen segments are black.

The legs on the trunk, the antennae on the head, and the tips of the legs on the last segment of the body are colored a medium dark yellow.

Notice that each leg is tipped with a sharply pointed terminal segment. Though often referred as one, this is not a true claw, but the third segment of the leg’s three-segmented tarsus. Some sources report that their sharp points damage unprotected skin, and that poison glands are located at the junction of each leg with the body.

When the centipede travels over your skin, the claw may penetrate, and venom may be deposited in the cut, producing local inflammation. Of course, I have not tested this hypothesis, and some investigators dispute it as fanciful fiction…

Giant Centipede (Scolopendra heros), Temple. Texas–leg and claw

Centipedes are common in central Texas, where they prefer to live outdoors in damp places, under leaves and stones. They are members of the phylum Arthropoda (they have articulating, jointed legs) and the class Chilopoda (from the Greek , cheilos, meaning “lip” or “jaw” and pous, meaning “foot”, in combination meaning “jawwed foot”, a reference to the claws on each leg that have the appearance of teeth). Their jaws, which are connected to venom glands, are used to kill prey. If handled, they are capable of injecting venom, so caution is advised.

If you are pestered by centipedes, inside or outside your home, the first step is to determine why they are there. Next, become informed on least toxic or non-toxic methods available to eliminate them from your home and yard. Those methods should include identifying and correcting conditions conducive to the breeding and congregation of these organisms.

The legs on the first segment behind the head have been modified into hollow tubes, with openings at their sharpened tips, so that they function as fangs. They are attached to venom glands, and are used to kill prey.

Giant Centipede (Scolopendra heros), Temple. Texas–ventral anterior

Centipedes of this species reportedly do not attack organisms larger than themselves, including humans, unless molested. Your definition of “molested” may differ from that of the centipede, however. The three small snakes this guy killed probably just happened to get too close at the wrong time.

The centipede’s bite is considered about as serious as a bee sting, but the risk of secondary infection is also important to consider. Because centipedes are opportunistic feeders, and will scavenge dead animals and excrement that it encounters during foraging activities, it may be an efficient reservoir and vector for pathogens that such food sources may contain. Some authorities discount this possibility, however. Texas A&M scientists recommend that centipedes never be handled by humans, to avoid the risk of being bitten.

The photo on the left was taken through the wire mesh of the enclosure lid while the centipede was exploring. Note the fangs on each side of the head, with orange coloration and darkened, nearly black tips. These are the appendages that are used by the centipede to stun and kill its prey.

The body segment the fangs are attached to is thickened, suggesting that its musculature is unusually stout. Once the centipede positions its fangs for an attack, it is able by virtue of these muscles to sink them deeply into the body of its prey, even through a tough cuticle.

Giant Centipede (Scolopendra heros), Temple. Texas–dorsal posterior

Giant Centipede (Scolopendra heros), Temple, Texas–ventral posterior