Narceus gordanus (Chamberlin 1943)

Narceus gordanus (Chamberlin)
Spirobolus gordaniis Chamberlin, Bull. Univ. Utah, biol. ser., vol. 8, no. 2, p. 5,
figs. 6-11. 1943. Arctobolus keysi Loomis, Psyche, vol. 51, p. 169, fig. 2. 1944. New synonymy. Narceus gordanns Chamberlin, Amer. Midi. Nat., vol. 50, p. 150. 1953. Narceus gordanus, Causey, Journ. Kansas Ent. Soc, vol. 28, p. 75. 1955. Narceus keysi, Causey, ibid., p. 75.
Narceus keysi, Causey, Proc. Biol. Soc. Washington, vol. 70, p. 205. 1957. Narcetis gordanus, Chamberlin and Hoffman, U. S. Nat. Mus. Bull., no. 212, p.
166. 1958. Narceus keysi, Chamberlin and Hoffman, ibid., p. 166. Narceus gordanus, Keeton, Bull. Brooklyn Ent. Soc, vol. 54, p. 7. 1959.
Nomenclatorial Considerations. — I have examined the type of keysi and am thus sure that that name is based on the species here described. I have been unable to study the type of gordanus, but Chamberhn's mention of the large size of the male prefemoral endite and of the only slight production of the male pregenital coxae seems to fit this species despite his description of the color, a variable character.
Diagnosis. — Differs from the other species of Narceus in having much shorter legs, a larger, differently shaped collum which covers much of the head, much deeper antennal grooves, carinate parietal sclerites which do not taper caudad, more labral setae, very thin distal lobes of cyphopods, broader prefemoral endites of posterior gonopods, and less production of male pregenital coxae. Other differences in meristic characters are shown in Tables 14—21.
Description. — L of males 66-114 mm. (94.2), of females 59-119 mm. (93.3) ; W of males 7.0-12.2 mm. (10.41), of females 6.9-12.8 mm. (10.45) ; L/W of males 8.1-9.8 (9.0), of females 7.2-9.8 (8.9). Segments 45-54 (49.9).
Segment rings light greenish tan on dorsum and sides, often becoming steel grey below ; posterior half of each hind belt slightly darker tan. Cephalic margin of collum, extreme caudal margin of telson, caudal margin of anal scale, and anal lips reddish brown. Face and antennae moderately dark brown ; eyes black. Legs dark brown. Specimens often become darker at death but generally fade to very light tan after a year or more in alcohol. Color varies considerably between localities, e.g. live specimens examined from Ocala, Florida were darker than live specimens from Highlands Biological Station (of possible interest is the fact that the latter occurred in a substrate of very light-colored sand).
Antennal groove very deep, strongly delimited both anteriorly and posteriorly. Parietal sclerite carinate at border of antennal groove ; sclerite narrowing abruptly behind carina. Mandibular cheek deeply grooved for reception of antenna. Eyes per patch 37-59 (46.0). Clypeal setae 8-12 (10.1); labral setae 19-35 (25.5).
Collum broad, covering much of head; half of eye patch, most of antennal groove, and base of mandibular cheek hidden ; anterior margin of collum angling slightly forward at level of eye patches. Second segment produced below ends of collum but the productions not long, usually rounded.
Tergites not as densely punctate as those of other species of Narceus; few rugulae.
Anal lips often indistinct or absent.
Pregenital coxae of male not much produced ; those of 3rd-5th legs usually with short, broad lobes. All legs very short, not reaching sides of body when held horizontally. Few ventral setae (e.g. 1-0-0-1-2-4).
Gonopods of usual Narceus type except coxal endites often very broad, and prefemoral endites usually broad, twisted at base, truncate distally.
Cyphopod very thin distally. Distal corner of lateral flange often produced to form prominent tooth.
Type. — Male (RVC, Chamberlin says in publication, " Field Museum " ; cannot be located at present) . Locality : Punta Gorda, Florida. Type of keysi: male (MCZ). Locality: Lantana, Florida.
Distribution. — Peninsular Florida north to South Carolina and (?) Tennessee. The specimens from Tennessee here reported were in a large jar containing other Narceus species ; they may have been mixed erroneously at some time.
Specimens Examined. — 164 (78 males, 86 females).
Florida.— "Florida. July-Aug., 1925" (1 male) (USNM). Alachua County: 1948 (1 male, 1 female), C. J. Coin (RLH) ; Gainesville, Oct. 11, 1929 (2 males, 2 females), O. F. Cook (USNM), March, 1931 (2 females). Cook (USNM); Gainesville, Paynes Prairie, Oct., 1929 (1 male). Cook (USNM). Broward County: Deerfield, Aug. 19, 1929 (2 females). Cook (USNM). Collier County: Cape Romano (2 females) (USNM); Naples, Sept. 23, 1928 (3 males, 10 females), O. F. Cook (USNM). Hernando County: betw. Brooksville and Dade City, Nov. 8, 1929 (1 male). Cook (USNM). Highlands County: Highlands Biological Station, Aug., 1958 (43 males, 41 females), T. Eisner, J. Nowosielski, R. S. Payne (TE). Hillsborough County: Tampa Springs (1 male), W. M. Beakley (ANSP). Lake County: betw. Astor and Altoona, Sept. 20, 1928 (1 male, 3 females). Cook (USNM). Marion County: Ocala, Aug., 1958 (17 males, 13 females) (TE) ; Ocala National Forest, Oct., 1929 (1 female). Cook (USNM). Palm Beach County: Lantana, Dec, 1944 (2 males), A. Keys (USNM), May 12, 1944 (male, type of keysi), A. Keys
(MCZ); near Palm Beach, Aug., 19, 1929 (1 female), Cook (USNM). Polk County: betw. Fort Meade and Wauchula, Sept. 21, 1928 (3 males, 4 females), Cook (USNM). Saint Johns County: St. Augustine (1 male) (MCZ).
South Carolina. — Charleston County: James Island, Sept. 15, 1928 (1 female). Cook (USNM).
Tennessee. — Carter County: Burbank (3 females), R. Thaxter (MCZ).

Narceus gordanus is a spirobolid millipede native to the southeastern United States. Common names include Smokey Oak Millipede and Smokey Ghost Millipede. Adults range from around 60 to 120 mm (2.4 to 4.7 in) in length, up to 13 mm wide, and possess 45 to 65 body segments. The body color is lighter than other species of Narceus, with each body ring a light greenish tan followed by a band of darker tan. N. gordanus also has shorter legs than other Narceus species, and a deeper groove on the head in which the antennae rest.

Narceus gordanus occurs in Florida scrub habitat of peninsular Florida, and ranges as far north as South Carolina, with possible records in Tennessee. N. gordanus matches the color of sand in some Florida habitats, even though it is mainly active at night. Narceus gordanus, similar to other millipedes, responds to threats by secreting a foul-smelling and tasting fluid and coiling into a defensive spiral to protect its underbelly and head. When exposed to human skin, these secretions can cause a harmless discoloration known as millipede burn. Their diet consists of decaying leaves, wood, and other detritus.