Floridobolus Causey, 1957

Shelley, Rowland M. & Floyd, Samuel D., 2014, Expanded concept of the milliped family Spirobolidae Diplopoda: Spirobolida: Spirobolidea): Proposals of Aztecolini n. tribe and Floridobolinae / ini and Tylobolini n. stats.; (re) descriptions of Floridobolus and F. penneri, both Causey, 1957, and F. orini n. sp.; hypotheses on origins and affinities, Insecta Mundi 2014 (357), pp. 1-50 : 14-16

Genus Floridobolus Causey, 1957

Floridobolus Causey, 1957:206 . Hoffman and Keeton, 1960:14. Jeekel, 1971:198. Hoffman, 1980a:77;

1999:48. Shelley et al., 2000:20. Shelley, 2001a:243 .

Type-species. F. penneri Causey, 1957 , by original designation.

Diagnosis. With the characters of the tribe ( Fig. 1–5 , 14–21 , 33 ). Components. Two species, F. penneri Causey, 1957 , and F. orini , n. sp., are known; undiscovered populations and undescribed species likely inhabit other sandy ridges and “Big Scrub” habitats in Florida.

Distribution ( Fig. 13 ). Apparently restricted to the arid, sandy Central Highlands of Florida, Floridobolus is known only from the Lake Wales Ridge, Highlands and Polk cos., and the Ocala National Forest, some 208 km (130 mi) to the north in Marion Co.

Origin. As it exists today, Floridobolus could have evolved ~303 mya or anytime later up until 25 mya, the earliest date that Floridobolini could have invaded peninsular Florida. There is no reason to believe that this geographically restricted genus arose simultaneously with the family/subfamily/tribe or that no other floridobolinine genera ever existed, but no evidence exists suggesting otherwise. Therefore, we can only assume that Floridobolus arose simultaneously with the tribe/(sub)family and arbitrarily set its age at <303 my.

Remarks. Narceus gordanus and Floridobolus spp. are the only eastern spirobolids whose male 7 th pleurotergites are not enlarged and whose bodies are not distorted in this region. Individuals of Floridobolus are also the only spirobolidans whose bodies taper at both ends, are wider than high, and whose profiles are transversely ovoid ( Fig. 33 ). All southeastern spirobolids coil rapidly, but Floridobolus is unusual in that individuals rapidly uncoil, particularly in comparison to sympatric N. gordanus and C. spinigerus . Perhaps this unusual ability is facilitated, or even enabled, by the somewhat “flattened” body form.

Floridobolus penneri and F. orini are similar anatomically, but only the former has the extraneous basal process, termed “lateral process” by Keeton (1960b), on the caudal surface of the posterior gonopod telopodite. This plus allopatry and the totality of small differences ( Table 4) mandate specific recognition of the form in the Ocala National Forest.

Floridobolus penneri is commonly known as the “ Florida Scrub Milliped” ( Deyrup 1994) because it inhabits environments with low growing, shrubby plants in dry, sandy soil. With a second species now known, this environmental characteristic is properly attributable to the genus, and we recommend that Floridobolus be labeled the “Genus of Florida Scrub, Spirobolidan Millipeds.” More species likely occur in other patches of scrub habitat, the research topic of an RMS graduate student, but a chance discovery as with the holotype of F. orini seems unlikely. Nocturnal investigations and long-term pitfall trapping seem the best techniques for finding Floridobolus ; the holotype and only specimen of Arvechamboides ocala Shelley, 2007 ( Julida : Parajulidae ), also endemic to scrub habitat in the Ocala National Forest, was discovered in a pitfall trap ( Shelley 2007a , b).

Figures

Figure 13. Distributions of Floridobolini and Floridobolus. Star, type locality of F. orini. Black line, known and projected distributions of F. penneri on the Lake Wales Ridge. AR, course of the Apalachicola River in Florida. H, Highlands Co. M, Marion Co. P, Polk Co.

Figure 33. Ring profiles in Spirobolidae. Left two rings, transversely ovoid profile shown by Floridobolinae/ Floridobolini. Right two rings, rounded profile demonstrated by Floridobolinae/Tylobolini and Spirobolinae. Photo courtesy of O. McMonigle.

Figures 1–5. Floridobolus orini holotype. 1) Head, collum, and anterior pleurotergites, dorsal view. 2) The same, right sublateral view. 3) Entire body, dorsal view. 4) The same, dorsolateral view. 5) Paraprocts, epiproct, and caudal pleurotergites, caudolateral view.

Figures 14–21. Floridobolus spp., gonopodal features. 14–17) F. penneri holotype.14) Left anterior gonopod, anterior view. 15) Telopodite of left posterior gonopod, anterior view. 16) The same, caudal view. 17) Bifurcate projection of anterior surface of the same, anteriomedial view. 18–21) F. orini holotype. 18) left anterior gonopod, anterior view. 19) Telopodite of left posterior gonopod, anterior view. 20) The same, caudal view. 21) Bifurcate projection of anterior surface of the same, anteriomedial view. A and C, anterior and caudal surfaces, respectively, of posterior gonopod acropodite. at, anterior gonopod telopodite. ce, coxal endite. db, dorsal branch of bifurcate projection. s, sternum. vb, ventral branch of bifurcate projection. asterisk (*), prefemoral process. x, extraneous basal process.