Nevadesmus ophimontis Shear

Shear, William A., Taylor, Steven J., Wynne, Judson & Krejca, Jean K., 2009, Cave millipeds of the United States. VIII. New genera and species of polydesmidan millipeds from caves in the southwestern United States (Diplopoda, Polydesmida, Macrosternodesmidae), Zootaxa 2151, pp. 47-65 : 59-61

Nevadesmus ophimontis Shear , new species

Figs. 3 , 7, 10 , 25–31 , 36 , 37 .

Types: Male holotype, male and two female paratypes from Model Cave, White Pine Co., Nevada, collected 23 May 2003 by S. J. Taylor, J. K. Krejca, K. Patel, M. Porter, K. Dittmar de la Cruz, deposited in FMNH. The following specimens (deposited at FMNH and INHS) are also paratypes: NEVADA: White Pine Co., same data as holotype, but collected 22 May 2006 by J. K. Krejca, M. E. Slay, G. Baker, 2 females; Snake Creek Cave, 29 May 2003, S. J. Taylor, J. K. Krejca, K. Patel, L. D. Seale, A. Hamilton, S. Johnson, 5 females; 21 May 2006, S. J. Taylor, J. Krejca, M. E. Slay, 3 males, juveniles; Lehman Caves, 26 May 2006, S. J. Taylor, J. K. Krejca, M. E. Slay, G. Baker, 3 males, 3 females; Little Muddy Cave, 23 May 2003. S. J. Taylor, J. K. Krejca, M. Porter, K. Dittmar de la Cruz, a juvenile male presumed this species; Wheeler’s Deep Cave, 26 May 2003, S. J. Taylor, J. K. Krejca, M. Porter, K. Dittmar de la Cruz, 2 males, 2 females.

Description: Male: Length, 4.5 mm, width 0.45 mm ( Fig. 37 ). Antennae short, clavate; head about 40% wider than collum. Collum with arcuate anterior margin bearing 12 short, clavate setae, posterior margin slightly procurved, with 6(5) marginal setae. Second segment slightly wider than collum. Typical midbody segment (segment 10; Fig. 3 ) with inconspicuous paranota, two paranotal teeth on each side (possible third tooth is directly opposite ozopore), posteriolateral corner right-angled to slightly obtuse, not drawn out beyond ozopore into sharp process. Metazonital setae on modest tubercles, short, clavate; anterior row of six, with lateralmost setae on each side posteriorly displaced; middle row of four setae, slightly procurved; marginal posterior row of four (six on some segments) setae; usual triad of setae subtends ozopore. Pygidium ( Fig. 7 ) short, rounded, with eight setae, pygidial process very short, blunt, bearing usual four spinnerets.

Pregonopodal legs encrassate. Gonopods ( Figs. 25–31 ) with hemispherical coxae tightly appressed in midline, excavated to receive retracted telopodites. Prefemora densely setose, strongly transverse, articulating process acute; exomere arising from anteriomesal margin of prefemur, long, thin, sinuous. Endomerite from distolateral edge of acropodite, basally broad, incurved, ending in three unequal processes, middle one longest. Subtending process of solenomere is set low and laterally on acropodite, seminal pore with relatively few cuticular teeth.

Female: Length, 4.8 mm, width 0.5 mm. Nonsexual characters as in male; cyphopods not studied.

Distribution and habitat: As shown by the map ( Fig. 36 ), the caves occupied by Nevadesmus ophimontis are relatively closely clustered, and all are located in Great Basin National Park. Model Cave is a large cave (length 599.9 meters [1968.1 feet]) at an elevation of 2080 meters (6824 feet). The fauna of Model Cave is dominated numerically by Collembola , followed by mites, mayflies, and flies. Globular springtails ( Arrhopalites spp.) including an undescribed species, were particularly abundant. In addition to N. ophimontis , three troglobitic or troglophilic species are present, including the sclerobunine harvestman Cyptobunus ungulatus ungulatus Briggs , the conotylid milliped Idagona lehmanensis Shear (see Shear 2006), and the pseudoscorpion Microcreagris grandis Muchmore. Surrounding vegetation ( Fig. 38 ) for all the caves listed as supporting populations of N. ophimontis is Great Basin pinyon-juniper woodland (SWReGAP land cover type; Lowery et al. 2006).

Lehman Caves, at an elevation of 2096 meters (6877 feet), is the largest (length ~3352.8 meters [~ 11,000 feet]) cave in the Great Basin National Park. The fauna includes Collembola, Diptera , and mites, in addition to M. grandis and N. ophimontis . Notably absent from the Lehman Caves, in spite of intensive collecting, were C. ungulatus ungulatus and Idagona lehmanensis . Eight taxa of Collembola have been collected in this cave.

Little Muddy Cave is a large cave (length 309 meters [1010.5 feet]) at an elevation of 2045 meters (6709 feet). Microcreagris grandis occupies this cave; it is a possible predator on N. ophimontis . Snake Creek Cave is a large (length 51.3 meters [1682 feet]) cave at an elevation of 2030 meters (6660 feet), and located on a fairly barren, south facing slope ( Fig. 38 ). Springtails and the psocopteran Speleketor sp. were dominant in collections.

Wheeler’s Deep Cave is one of four interconnected caves making up the Baker Creek Cave System, Nevada’s longest cave (length 1315 meters [4315 feet]). It is located at an elevation of 2147 meters (7044 feet) in a limestone outcrop adjacent to the riparian zone of Baker Creek. Cyptobunus ungulatus ungulatus and N. ophimontis are fairly common in the deeper, wetter parts of this cave, where a perennial stream is present.

Etymology: The species name refers to the Snake Mountain Range, and to Snake Valley, major geographical features associated with the collection localities.

Figures

FIGURE 36. Map of parts of the states of Arizona, California, Nevada and Utah, showing localities for milliped collections (Map by S. Taylor).

FIGURES 3 – 6. Segments 10, dorsal view. Fig. 3. Nevadesmus ophimontis. Fig. 2. Pratherodesmus ecclesia. Fig. 3. P. despaini. Fig. 6. P. voylesi.

FIGURES 7 – 10. Figs. 7 – 9. Pygidia, dorsal view. Fig. 7. Nevadesmus ophimontis. Fig. 8. Pratherodesmus despaini. Fig. 9. P. voylesi. Fig. 10. Metazonital setae anterior to ozopore of segment 10, Nevadesmus ophimontis.

FIGURES 25 – 29. Gonopods of Nevadesmus ophimontis. Fig. 25. Posterior view. Fig. 26. Anterioventral view. Fig. 27. Lateral view. Fig. 28. Gonopods in gonostome, ventral view. Fig. 29. Solenomere, posterior view.

FIGURES 30 – 35. Drawings of gonopods. Figs. 30, 31. Nevadesmus ophimontis. Fig. 30. Lateral view. Fig. 31. Mesal view. Fig. 32. Pratherodesmus despaini, posteriolateral view. Fig. 33. P. voylesi, mesal view. Figs. 34, 35. P. ecclesia. Fig. 34. Posterior view. Fig. 35. P. despaini, mesal view.

FIGURES 37, 38. Fig. 37. Living example of Nevadesmus ophimontis, photographed in Snake Creek Cave; length of animal is about 5 mm. Fig. 38. Great Basin pinyon-juniper woodland of the Snake Mountains seen from just inside the entrance to Snake Creek Cave (photos by J. Krejca).