Dirk Stevenson (Altamaha Environmental Consulting)
Just in time for spooky season, join Dirk Stevenson on the hunt for rare and endemic millipedes in the southeast!
A morning check of drift fence traps is always exciting. The half-mile long path to my fence arrays, located in fire-managed and picturesque longleaf pine uplands, skirts two active tortoise burrows (I suspect the residents recognize me by now!). I walk on, past the well-worn foraging pad made by a momma gopher frog on the ground surface just outside a remnant pine stump, around a small cypress pond where I once heard a gator bellow, beneath the chatty members of a red-cockaded woodpecker family.
My funnel traps do not disappoint. Drawing back their shade covers and peeking under the funnels and sponges I see they have captured turquoise-bellied racerunners (Aspidoscelis sexlineata) and several examples of the gorgeous red reptilian bracelets (scarlet snakes, Cemiphora coccinea coccinea) that hunt them, and their eggs. There are several wolf spider females of a size sufficient to dampen the spirits of all but the most sincere of arachnologists. And today, I witness a major movement of a handsome spirobolid millipede; my funnels capture over 50 individuals of this large and vibrant species—which I suspect may be Chicobolus spinigerus (the Florida ivory millipede).
Millipede specialist Dr. Bruce Snyder of Georgia College and State University−Milledgeville and his first lieutenant, graduate student Lance Andrew, confirm my ID and make a plea for millipede specimens from Georgia. Bruce and Lance are conducting a two-year comprehensive inventory of the millipede fauna of the state. The Coastal Plain region of the southeastern U.S. supports an unusual fauna, including many endemic species.
Florida ivory millipedes are spirobolids and, like their name suggests, curl into a tight coil when threatened. Agitate them further and pore-like glands located along the body secrete noxious, quinone-laden toxins that get smeared upon the head (which lacks glands) in the process. An analogy a herp-literate crowd can appreciate would be an upside down writhing hognose snake slathering itself with musky poop during the climax of death-feigning. Quinones cause itching and pain, leading most predators to cease and desist (and wipe their faces on the ground!).
Alas, there are still ways to eat spirobolids. Florida scrub jays have learned to quickly decapitate these millipedes and consume their heads, leaving macabre piles of headless exoskeletons behind. And don’t forget those creepy phengodids, a family of strange beetles that are bioluminescent and highly specialized to dispatch spirobolids.
Phengodids are called “railroad worms” or “glow-worms.” Adult females remain larviform, never transforming, and light organs along their wormy bodies, when aglow, cause them to resemble miniature railroad cars. Larvae and females grab spirobolids by the head, and with sickle-shaped, needle-sharp mandibles bite into the neck tissue and inject gastric fluid that rapidly paralyzes the millipede and liquefies its tissue. All this occurs before the victim can discharge its defensive secretions. I collected a number of large (ca. 3-4 inch) female Phengodes laticollis in my funnel traps and kept one briefly as a pet. I was disturbed by how quickly it terminated the Chicobolus I introduced into its terrarium. As the literature states, it sucked out the contents of the millipede’s head before tunneling, posteriorly, inside the cylindrical corpse to ingest the now soupy innards.
The fascinating endemic-to-Florida Floridobolus millipedes are only found in xeric scrub and sandhill habitats and, like Florida scrub jays, have close relatives in western North America. There are three species of these especially stout, lead-colored spirobolids, each restricted to its own island of arid, ancient sand: Floridobolus penneri (Lake Wales Ridge), F. floydi (Brooksville Ridge), F. orini (Ocala Region). Remarkably, 57 years passed between the description of F. penneri and the discovery of the other two species in 2014, leading one to surmise that these millies are highly fossorial, not terribly vagile, and locally distributed. They have been found prowling late into the night following rains.
Millipedes are found the way herps are — by gently turning leaf litter, investigating rotten logs, flipping rocks, peering under bark, walking the forest on warm wet nights. When I accompany Bruce and Lance in the field, I notice they pore endlessly over a single log or a fat stack of leaves—many millipedes are quite small, scarcely macroscopic. A three-pronged “garden claw” is the millipede hunter’s best friend, and over time, as my personal species list mounts, mine becomes quite dear to me.
Yes, most millipedes prefer mesophytic forests, lush humid coves and ravines where deciduous litter piles deep on rich soils. However, a number of interesting species are confined to the sandier pineland provinces of the Coastal Plain. A large number of these millies are surface-active only during the winter months, a time when fewer millipede scholars are afield. Thus, there is abundant opportunity for scientific discovery.
Bruce and Lance covet mature male specimens, as the single most important taxonomic character defining a millipede species are the male gonopods. One-two pairs of legs on the seventh segment of male millipedes transform into gonopods as the males mature. The shape and size of these sperm-transfer appendages are species-specific. Diplopodologists earn their stripes by the delicate surgical practice of teasing out the gonopods under a dissecting microscope. The oddly beautiful gonopods are diaphanous and lemon yellow under magnification.
A November email from Dr. Snyder reads, “It’s parajulid season.” Right in my wheelhouse, as the members of this family are known as the “snake-like millipedes.” Two species we are dearly hoping to find in Georgia are Gyniulus bufonius – the type specimen of that was removed from the stomach of an eastern spadefoot toad in 1932 by none other than decorated herpetologist/writer Archie Carr – and Arvechambus weemsi, a two-inch long species known from only a single male collected in 1962 north of the Okefenokee Swamp. In her scientific article describing this species, Nell Causey remarked, “They look like freaks, for the gonopods are the strangest in the entire family.” I think they resemble the foreclaws of Tyrannosaurus rex.
Scouring sand ridges above the Alapaha and Altamaha Rivers, I collect a number of “snakes” later determined by Bruce and Lance to be Arvechambus weemsi! Later in winter, Lance scores the first ever Gyniulus bufonius from Georgia!
Next came hunts for “winter xystos” (i.e., constituents of the speciose family Xystodesmidae, which includes the sweet-smelling, psychedelically-colored cherry millipedes). I so hope to find a Caralinda species. The five described forms in this genus occur only in the Coastal Plain; some have been documented from longleaf pine uplands supporting gopher tortoises.
The carapace of a Caralinda spp. is patterned with all shades of tan and almond and glistens as if dipped in honey. When conditions are just so—picture warm-muggy-rainy winter weather—they emerge en masse from the ground with the spontaneity of ambystomatid salamanders. They emerge in swarms, mass aggregations sometimes collecting along the sides of buildings or on walkways.
A humid December afternoon finds me scratching about for millipedes in pine-oak forest west of Savannah. I turn up some of the usual suspects including a common blond-hued species with a musical name, Dicellarius okefenokensis. I scratch some more, this time deeper, several centimeters, into the soil. Wait, could it be!? I can hardly believe what I uncover, and grab my reading glasses and loupe to confirm. Hmm, yes, it resembles a Carlinda species, but in miniature. YES—it sports gonopods. It’s a male!
My millipede mentors in Milledgeville congratulate me. On their ever-burgeoning species list of millipedes known from Georgia (ca. 150 species, including a number of undescribed forms; second nationwide only to California), they add a new line item: Caralinda new sp. “Dirk”.
