Myrmecodesmus reddelli, Shelley, 2004

Shelley, R. M., 2004, The milliped family Pyrgodesmidae in the continental USA, with the first record of Poratia digitata (Porat) from the Bahamas (Diplopoda: Polydesmida), Journal of Natural History 38, pp. 1159-1181 : 1175-1176

Myrmecodesmus reddelli , new species

(figures 7, 11, 17–20)

Type specimens. One male and three female syntypes ( FSCA) collected by J. R. Reddell, 15 March 1969, 7.5 mi (12.0 km) N Boerne, Kendall County, Texas. I designate syntypes instead of a holotype and paratypes because, after noting somatic features of the male, I had to dissect the gonopods, which resulted in fragmentation such that I could no longer distinguish the parts of the male from those of the already fragmented females .

Diagnosis. Porosteles present on segments 5, 10, 13 and 16. Crests on caudalmost segments diminished in height and only slightly overhanging sides of epiproct, barely extending beyond level of its caudal extremity, tip of epiproct visible in dorsal view between crests (figures 17, 18).

Male syntype. Twenty segments including epiproct. Length ca 3.4 mm, maximum width ca 0.6 mm. Colour subuniformly dark brown; body heavily sclerotized. Collum with low, rounded indistinct pustules, anterior margin relatively flat, not appreciably upturned, scallops moderately distinct, middle two most strongly segregated, lateralmost shallowly and indistinctly separated (figure 7). Second tergite with typical three-lobed paranota, paramedian tubercles coalesced into low, indistinct carinae, caudal segmental margin smooth and sublinear, slightly crenulated laterad. Remaining tergites more strongly crenulated laterad, carinae becoming progressively more distinct through segment 17 though always lower than in M. formicarius and M. digitatus ; carinae on segments 18–19 reduced, those on 19 slightly overhanging sides of epiproct, tip of latter visible between crests (figures 17, 18). Paranota with two moderately distinct lobes on all segments subsequent to segment 2, lobes subequal in size on non-poriferous segments, anterior lobe much larger on poriferous segments; porosteles present on segments 5, 10, 13 and 16, positioned between lobes (figure 11). Epiproct small and smoothly rounded, without lobes or crenulations. Legs and sterna without modifications.

Gonopod (figures 19, 20) minute, details visible only under high magnification; telopodite generally uncinate, presumed solenomere a short, gently curved projection arising at two-thirds length on caudal surface, tip of telopodite divided into three branches, anteriormost subdivided. Prefemoral process much shorter than telopodite, bent caudad distally, apically bifurcate.

Female syntypes. The female syntypes are light brown in colour but otherwise agree closely with the male in somatic features.

Ecology. The habitat at the type locality is not indicated on the vial label.

Distribution. Known only from the type locality. With only one sample, we have no way of determining whether M. reddelli is introduced from a neotropical locale, native to this region of Texas, or possibly even endemic. I suspect that, like M. formicarius , it is a Mexican species that ranges northward into southern Texas and hence is indigenous.

Etymology. I am pleased to name this species for the collector, J. R. Reddell, of the Texas Memorial Museum, Austin, in recognition of his continued helpfulness to me in providing research material and his lifetime of collecting myriapods in Texas and Mexico, particularly from caves.

Remarks. In studying this milliped, I examined holotypes of every species from Mexico and one from Cuba that appeared from published descriptions to have a somewhat similar gonopod (listed in the acknowledgements), but none matched M. reddelli either in somatic features, gonopodal configuration or both; the closest was M. mundus (Chamberlin) , from Veracruz (city), Mexico, some 800 mi (1280 km) to the south. Even at 400×, the highest magnification on my Nikon compound microscope, I was unable to resolve the course of the prostatic groove and which branch is the solenomere, which may require scanning electron microscopy. However, a review of the literature (Shear, 1973, 1977) indicates that it is probably the proximal branch as in other species of the genus, and Dr Shear (in litt.) has so advised me, hence the characterization of ‘presumed solenomere’ in the description and the label as such on figures 19, 20. As M. formicarius ranges northward from Mexico into Texas, it seems likely that M. reddelli does too and that it is indigenous, but not endemic, to Texas. Without question, there are many undiscovered pyrgodesmid species in Mexico and Central America, and there may be still others that range northward across the Rio Grande into the southern reaches of Texas.