Agathidium falcatoperculum Wheeler and Miller, 2005

WHEELER, QUENTIN D. & MILLER, KELLY B., 2005, Slime-Mold Beetles Of The Genus Agathidium Panzer In North And Central America, Part I. Coleoptera: Leiodidae, Bulletin of the American Museum of Natural History 2005 (290), pp. 1-95 : 83-85

Agathidium falcatoperculum Wheeler and Miller , new species Figures 100 , 169–177

TYPE MATERIAL: Holotype, Ƌ in FMNH labeled ‘‘WASH:Jefferson Co Olympic NP, 0–3.4 mi SW Hoh 400–500′ VII.16.1975 A.Newton, M.Thayer/ leaf litter mixed hardwood­conifer forest/ HOLOTYPE Agathidium falcatoperculum Wheeler and Miller, 2002 [red label with black line border]’’.

TYPE LOCALITY: United States, Washington, Jefferson Co., Olympic National Park, 3.4 mi SW Hoh.

DIAGNOSIS: This species very closely resembles A. virile and A. angustoperculum , from which it may be distinguished by the curved, convergent, and sometimes apically overlapping rami of the ventral operculum of the median lobe (fig. 177).

DESCRIPTION: Body very broadly elongate oval, partially contractile, moderately convex (figs. 173, 174); TBL = 3.0– 3.1 mm. Color of head, pronotum, and elytra red; ventral surface red; mouthparts and appendages reddish­brown; antenna uniformly reddishbrown; legs reddish­brown.

Head large, broad, subquadrate in shape, narrowed behind eye, temporum short (figs. 173, 174) (about three­fifths length of eye), present only as supraocular carina extending from posterior end of temporum to frontoclypeal suture; OHW/MDL = 1.5; OHW/ PHW = 1.0; dorsal surface with sparse, irregularly distributed, weakly impressed, small setigerous punctures, surface between with few, very small, irregularly distributed punctules (fig. 169); eye large; frontoclypeal suture very finely impressed, nearly obsolete, clypeal region made distinct by subcuticular darkened lines; surface of clypeus as on frons; without larger setae at posterolateral corners of clypeal region; labrum small, transverse, very shallowly emarginate medially; antennomere III about as long as IV + V + VI; length II:III = 1:2.2; VII very slightly wider than VIII, nearly equal in size; width VII:VIII:IX= 1:1:2.4. Pronotum broad, convex; PNW/PNL = 1.6; PNL/PNH = 1.4; PNW/PNH = 2.2; punctation similar to that of head (fig. 170). Elytra very wide; length slightly more than greatest width; slightly attenuate at apex; humeri not angulate, broadly obtuse; punctures much larger and more coarsely impressed than those of head and pronotum, irregularly distributed and moderately dense, distance between punctures about 0.5–2.0 diameter of single puncture, surface between smooth, shiny, with microscopic, nearly invisible and very sparse micropunctules and random faint curving lines (fig. 171). Mesosternum divid­ ed into anterior and posterior parts; anterior part with longitudinal median carina and fine alutaceous sculpturing; with oblique carinae and lateral, longitudinal carinae. Metasternum finely alutaceous, with laterally curved, concentric, rugose ridges, surface covered by fine setae. MSL/MTL = 0.8; MTL/MTW = 0.4.

Male tarsi 5–5–4; with pro­ and mesobasotarsomeres moderately expanded laterally; left mandible not modified; metafemur with conspicuous, broad, subapical tooth with small median protruding point; metasternal fovea in large anteromedial oval depression,

operculum Latin for ‘‘lid’’, signifying the curved condition of the rami of the operculum of the median lobe.

DISTRIBUTION: This species is distributed in the Pacific Northwest (fig. 100).

PARATYPES UNITED STATES: California: Fresno Co.: Sierra NF Tamarack Ridge, 34 m SE Cal. 168, 16 May 1976, under conifer bark, A Newton, M Thayer (1, FMNH) ; Mendocino Co.: MacKerricher State Park, 1 Dec 1978, FG Andrews (1, CASC). Washington: Pierce Co. : Mt Rainier NP 4.7 mi W Longmire, 20 Jul 1975, 2200′, A Newton, M Thayer (1, MCZC) .

DISCUSSION: This species has been collect­ ed from mixed hardwood­conifer leaf litter and from under bark. Elevation records are from 400 to 2200 ft.

transverse, with long fine setae (fig. 172). Aedeagus with median lobe elongate, robust, ventrally curved, in lateral view slightly recurved dorsally subapically, apical 1/5 dorsoventrally compressed and laterally narrowed before apex (fig. 176); in ventral view apex of median lobe narrowed, more­or­less arrowhead­shaped, with fanlike arrangement of ducts apically (fig. 176); operculum deeply bisected into pieces, each elongate, broad, with medial margin concave, curved, apex pointed and directed medially (fig. 177); lateral lobes long, gradually narrowed before apex that is slightly expanded subapically in ventral view, with pair of subapical setae and irregularly distributed pores (figs. 175, 176); endophallic armature not extensive.

Female tarsi 5–4–4.

ETYMOLOGY: This species is named from the words falcatus, Latin for ‘‘curved’’, and

CHECKLIST OF AGATHIDIUM SPECIES : PART 1

Agathidium sexstriatum species group

A. bistriatum Horn, 1880

A. sexstriatum Horn, 1880

A. estriatum Horn, 1880

Agathidium brevisternum species group

A. brevisternum Fall, 1934

A. rhinocerellum Wheeler and Miller , new species

A. dioperculum Wheeler and Miller , new species Agathidium revolvens species group

A. revolvens LeConte, 1850

A. jasperanum Fall, 1934

A. depressum Fall, 1934

A. dubitans Fall, 1934

A. dubitanoides Wheeler and Miller , new species

A. omissum Fall, 1934

A. cavisternum Fall, 1934

A. virile Fall, 1934

= A. hebetatum Hatch, 1957 , new synonym

A. conjunctum Brown, 1933

= A. obtusum Hatch, 1957 , new synonym

A. angustoperculum Wheeler and Miller , new species

A. falcatoperculum Wheeler and Miller , new species

Figures

Fig. 100. Geographic distribution of Agathidium revolvens group species: A. cavisternum Fall = ·; A. falcatoperculum, n.sp. = •; A. revolvens LeConte = *; A. omissum Fall = ^.

Figs. 169–174. Agathidium falcatoperculum, n.sp.: Figs. 169–171, punctation detail: 169, head; 170, pronotum; 171, elytron. 172. Male metasternal fovea. Figs. 173, 174, habitus: 173, dorsal; 174, lateral. bars = 0.5 mm.

Figs. 175–177. Agathidium falcatoperculum, n.sp., aedeagus: 175, lateral; 176, ventral; 177, operculum.