Plumatyla humerosa (Loomis) 1943

Figs. 251, 252

Conotyla humerosa Loomis 1943, p. 384 .

New records: All specimens CAS. CALIFORNIA: Lassen Co., Indian Cave, Lassen National Forest, 40.6683°N, - 120.8177°W, elev. 1618 m., dark zone, 15 September 2017, T. Rickman; Cave A-1-1, Lassen National Forest, 40.6100°N, - 120.8405°W, elev. 1621 m., 16 August 2018, T. Rickman, T. Blaschak, M. Immel, ff. Modoc Co., Damon’s Cave, Lassen National Forest, 41.5169°N, - 121.1825°W, elev. 1435 m., twilight zone, 9 May 2018, T. Blaschak, T. Rickman, mm ff; Black Stout Cave, Lassen National Forest, 41.6635°N, - 121.3338°W, elev. 1296 m., 14 May 2018, dark zone, T. Blaschak, T. Rickman, mm ff. Shasta Co., North Christmas Tree Cave, Lassen National Forest, 40.6681°N, - 121.4127°W, elev. 1322 m., 2 May 2018, twilight zone, T. Rickman, T. Blaschak, m; Cave 4, Lassen National Forest, 40.6682°N, - 121.4161°W, elev. 1336 m., 9 August 2018, T. Rickman, mm; Cave 5, Lassen National Forest, SW tube, 40.6725°N, - 121.4109°W, elev. 1352 m., 24 May 2018, entrance and twilight zone, T. Rickman, T. Blaschak, M. Immel, m; same as previous, but N tube, m f; Cave 6, Lassen National Forest, 40.6714°N, - 121.4110°W, elev. 1354 m., 24 May 2018, twilight zone, dark zone, T. Rickman, T. Blaschak, M. Immel, mm ff; Cave 51, Lassen National Forest, lower tube, 40.6663°N, - 121.4367°W, elev. 1404 m., 22 May 2018, twilight zone, T. Rickman, T. Blaschak, M. Immel, juvs.; Cave 56, Lassen National Forest, 40.6675°N, - 121.4367°W, elev. 1390 m., 22 May 2018, dark zone, T. Rickman, T. Blaschak, M. Immel, m; Cave 71 (Burnt Elderberry Cave), Lassen National Forest, 40.6930°N, - 121.4154°W, elev. 1304 m., 20 June 2018, twilight zone, T. Rickman, T. Blaschak, M. Immel, mm ff; Cave 80, Lassen National Forest, 40.6773°N, - 121.4177°W, elev. 1336 m., 20 June 2018, dark zone, T. Rickman, T. Blaschak, M. Immel, ff, juvs.; Cave 87, Lassen National Forest, 40.6683°N, - 120.8188°W, elev. 1172 m., 5 June 2018, twilight zone, T. Rickman, T. Blaschak, M. Immel, mm ff; Cave 166, Lassen National Forest, 40.6423°N, - 121.4264°W, elev. 1374 m., 30 August 2018, T. Rickman, T. Blaschak, M. Immel, ff. Siskiyou Co., Three Level Ice Cave, 41.3921°N, - 121.6676°W, elev. 1321 m., 25 August 2018, J. McFarland, mm ff; Rooty Tooty Cave, 41.4692°N, - 121.6299°W, elev. 1547 m., 26 August 2018, T. Rickman, J. McFarland, mm ff; Amazing Attic Cave, 41.4869°N, - 121.6446°W, elev. 1614 m., 25 August 2018, J. McFarland mm ff. Tehama Co., Wilson Lake Ice Cave, 40.3119°N, - 121.4237°W, elev. 1533 m., 14 June 2018, twilight and dark zones, T. Rickman, T. Blaschak, M. Immel, m f, juvs.; Wilson Lake Cave 2, 40.3433°N, - 121.4192°W, elev. 1759 m., 26 July 2018, T. Rickman, T. Blaschak, M. Immel, f; Wilson Lake Cave 3 (Cedar Cellars Cave), 40.3425°N, - 121.4252°W, elev. 1706 m., 14 June 2018, twilight zone, T. Rickman, T. Blaschak, M. Immel, f. OREGON: Lake Co., Derrick’s Cave, 43.5231°N, - 120.8645°W, elev. 1513 m., 30 August 2008, N. Marchington, mm .

Notes: Plumatyla humerosa seems to be quite general in northern California and south-central Oregon in lava tubes and some limestone caves, as well as mines nearby. Populations are frequently large, judging from the numbers of specimens in some collections. The gonopods (Figs. 251, 252) look uniform throughout the area, suggesting dispersal through porous lava and epikarst, but the possibility of cryptic speciation remains to be investigated by genetic study. The species is well-adapted to subterranean life but based on Pleistocene glacial history may not be an old troglobiont.