Idagona jasperi, Shear, William A., 2007

Shear, William A., 2007, Cave millipeds of the United States. V. The genus Idagona Buckett & Gardner (Chordeumatida, Conotylidae, Idagoninae), Zootaxa 1463, pp. 1-12 : 6-8

Idagona jasperi , n. sp.

Figs. 3 , 7, 11, 17, 19, 20

Types: Male holotype, paratypes from Utah: Cache Co., Nielsen’s Cave, Tony Grove Recreation Area, 8100’ (2469 m) elevation, Wasatch-Cache National Forest, J. Jasper, August 2006. Additional male paratype from same locality, but Main Drain Cave. 9 September 2006, G. Baker (all specimens FMNH).

Diagnosis: Distinct from I. westcotti in the more gracile gonopods (Fig. 7), with many fewer lateral teeth ( Fig. 3 ); the posterior gonopod sternum of westcotti has a median flange with acute corners; this is not seen in jasperi . The adenostyle of femur three ( Fig. 11 ) is more strongly constricted at the base in jasperi , and has a very obvious apical depression and large pore; in westcotti there are multiple small pores.

Etymology: The species is named for the collector, Jon Jasper.

Description: Male: 13.5 mm long, 1.0 mm wide. Fourteen ocelli in oval patch, ocelli round, black, compactly arranged. Legpair 3 ( Fig. 11 ) with femur enlarged, bearing prominent median adenostyle strongly constricted at base. Legpair 4 enlarged but with unmodified femora. Gonopods ( Figs. 3 , 7, 19, 20) similar to those of I. westcotti , but markedly more slender, more abruptly tapered distally; lateral apical teeth much reduced, median extension of posterior gonopod sternum low. Coxae 10 ( Fig. 17 ) enlarged but not extended distal to trochanteral joint, distal knob strongly acute, gland opening ventral. Coloration medium tan, extensively mottled with darker purplish-brown.

Distribution: Known only from the type localities. The caves with I. jasperi are in the upper reaches of Logan Canyon, about 20-25 miles northeast of Logan, Utah, in the southeast flank of the Bear River Range.

Notes: There is extensive karst development in Logan Canyon ( Spangler 2001; Jasper 2006) and many of the caves are at high altitudes, above 8000’. Nielson’s Cave, among others, harbors permanent ice or snowpack, as do some of the Snake River Plain lava tubes. Idagona jasperi specimens are recorded as actively walking over ice and snow, and like other elements of the faunas of these caves, are well-adapted to nearfreezing temperatures. The millipeds are described by collectors as being very abundant on wood and other organic debris in the caves (J. Jasper, pers. comm..to WS).

In contrast to the lava tubes of the Snake River Plain, the fauna of the caves of the Bear River Range is little known, and this report is the first for troglobitic or troglophilic terrestrial animals there. The compact, wellformed eyepatch and relatively dark pigmentation (when compared to I. westcotti ) would indicate a minimal degree of cave-adaptation in this species.

Earlier, Peck (1981) described invertebrate collections from the Uinta Mountains, to the southeast, and found that of 38 species collected in caves there, only three could be regarded as cave-limited. Peck (1981) attributed the relatively low number of troglobionts to the short time available since colonization. Up to about 12,000 years ago, severe periglacial conditions would have obtained, and as the glaciers melted, caves would have been scoured by powerful streams. No doubt this same analysis can also be applied to the high altitude caves of Logan Canyon, but with even less time available since colonization, as the montane glaciers in the more northerly Bear River Range would have retreated more slowly. Moist conferous forests surround the caves where I. jasperi has been found, and surface-dwelling populations may well exist there, but no collecting has been done. The caves may in fact only be refuges for the millipeds from the severe winter conditions that obtain in the region, and the animals may move freely between caves and forest litter. I strongly suspect that other, as yet uncollected, species of Idagona exist in caves and high altitude forests in other Utah (and Idaho) mountain ranges.

Figures

FIGURES 1 – 4. Gonopods of Idagona species. 1, Idagona westcotti, Giant Arch Cave, posteriorventral view. 2. I. westcotti, Ice Capades Cave, posterioventral view. 3. I. jasperi, n. sp. posterioventral view. 4. I. lehmanenesis, n. sp., posterior view.

FIGURES 9 – 14. Pregonopodal leg modifications of Idagona species. 9 – 12, third legs, anterior views. 9. Idagona westcotti, Giant Arch Cave. 10.. I. westcotti, Ice Capades Cave. 11. I. jasperi n. sp. 12. I. lehmanensis n. sp. 13. Leg 4 of I. lehmanensis n. sp., anterior view. 14. Denticles near adenostyle of leg 3 femur of I. lehmanensis n. sp.

FIGURES 15 – 18. Leg 10 coxae of Idagona species, posterior views. 15.. Idagona westcotti, Giant Arch Cave. 16. I. westcotti, Ice Capades Cave. 17. I. jasperi n. sp. 18. I. lehmanensis n. sp., anterior view.