Amplaria flucticulus, Shear, 2021

Shear, William A., 2021, The millipede family Striariidae Bollman, 1893. II. New records and species of the genus Amplaria Chamberlin, 1941 (Diplopoda, Chordeumatida, Striarioidea), Zootaxa 4908 (2), pp. 205-224 : 222-224

Amplaria flucticulus , new species

Figs. 42–44

Types: Male holotype and male paratype from Rippled Cave , 38.4386°, -120.7255°, Amador Co., California, col-lected 27 June 2009 by G. Graening and M. L. Gates. Parts of these specimens are mounted on SEM stub WAS 34–10 .

Diagnosis: An eyeless, presumably troglobitic species distinct from Amplaria shastae , also an eyeless troglobite and previously the only known one, in being approximately half the size of that species.

Etymology: The species name, a noun in apposition, is a Latin word meaning “ripple” and refers to the name of the type locality.

Description: Length about 12 mm, width 1.1 mm. Ommatidia absent. Mentum lacking hooks. Mandibles not modified. Legpairs 1 and 2 subequal in size; legpair 1 without needle-like setae on prefemora, femora and tibiae, tarsus with spatulate, twisted setae ventrally. Second trochanters with ventrolateral process bearing specialized setae ( Fig. 43 ). Coxal flasks of legpair 3 nearly asetose, long, slightly divergent, prefemora of telopodite with distinct dorsal swelling ( Fig. 43 ), telopodites not reduced in size. Postcoxal bars of ring 3 narrow, overlapping in midline ( Fig. 43 ). Coxae 4–7 not modified, telopodites 4–7 enlarged, podomeres flattened. Crests strongly developed ( Fig. 42 ); segmental setae inconspicuous. Pygidium short. Completely depigmented.

Gonopods ( Fig. 44 ) rather simple, anterior angiocoxites straight, narrow at base, expanded distally, with lateral terminal apophysis. poserior angiocoxites strongly curved, grapple-like, posterior branch much the largest, anterior branch sheathing 3–4 flagellocoxites. Ninth legs typical, with prominent curved coxal process.

Females not collected.

Distribution: Known only from the type locality.

Notes: Rippled Cave is owned by the Western Cave Conservancy and is part of the Weller Natural Preserve.

The cave is well-known, frequently visited and is excavated in marble. Access is controlled by the Western Cave Conservancy. The fauna of the cave had been extensively investigated in 1952 and 2002, but Amplaria flucticulus was not collected until 2009. Other potential arthropod troglophiles and troglobites are present and include spiders and springtails, but have not been identified in detail or remain undescribed (unpublished report from The Subterranean Institute, pers. comm. Graening 2020).

I presume that A. flucticulus is a troglobite based on eyelessness and complete depigmentation, but the antennae and legs do not appear significantly longer than in surface-dwelling species of the genus, nor is there any indication of “cave gigantism,” as seen in A. shastae . Amplaria flucticulus occurs in the central part of the Sierra Nevada, while two additional Amplaria species, A. adamsi Shear & Krejca, 2007 and A. muiri Shear & Krejca, 2007 are found in caves well to the south, in Kings Canyon and Sequoia National Parks. These latter species have pigmented ommatidia and presumably are troglophilic. Amplaria shastae from two caves in Shasta Co. ( Elliott et al 2017) is an undoubted troglobite.

Figures

FIGS. 41–44. Amplaria menocino, A. flucticulus. Fig. 41. Amplaria mendocino, legpairs 2–4 of male, ventral view. FIGS. 42–44. A. flucticulus. Fig. 42. Head, collum and rings 2–6, dorsolateral view. Fig. 43. Legpairs 2 and 3 of male, lateral view. Fig. 44. Right gonopod, lateral view.