Agathidium marae Miller and Wheeler, 2005

MILLER, KELLY B. & WHEELER, QUENTIN D., 2005, Slime-Mold Beetles Of The Genus Agathidium Panzer In North And Central America, Part Ii. Coleoptera: Leiodidae, Bulletin of the American Museum of Natural History 2005 (291), pp. 1-167 : 52-53

Agathidium marae Miller and Wheeler ,

new species Figures 23, 24 , 70, 71 , 91

TYPE MATERIAL: Holotype, Ƌ in WSUC labeled ‘‘ WASHINGTON: Mt. Spokane SP, nr Bald Knob Cmpgr. Spokane Co., 5200 ft. W. J. Turner 28­VI­1977 Malaise trap /HO­ LOTYPE Agathidium marae Miller and Wheeler, 2003 [red label with black line bor­ der]’’.

TYPE LOCALITY: United States, Washington, Spokane Co., Mt Spokane State Park, near Bald Knob Campground, 5200̍.

DIAGNOSIS: This species differs from others in the group by having concolorous dark red­brown elytra, no microreticulation on the head and pronotum, the anterior clypeal margin very strongly excavated (fig. 24), and the temporum forming a very abrupt, prominent rim at the posterior margin of the eye (fig. 24). Also, many males have a prominent left mandibular horn and a variously developed right frontal horn (figs. 23, 24). These horns are highly variable in development, but the right frontal horn is only well developed when the mandibular horn is also well developed. The median lobe of the aedeagus in lateral aspect is slender and elongate with a small basal portion and relatively simple apex (fig. 71). The lateral lobes are broadly fused dorsally for about one­third length of the median lobe of the aedeagus (figs. 70, 71). Females have 5­4­4 tarsomeres.

DESCRIPTION: Body moderately large (TBL = 2.52–2.67 mm), rotund (PNW/TBL = 0.43–0.45), laterally broadly rounded, strongly contractile.

Head dark red­brown with indistinct red medial macula; pronotum, elytra, and venter dark red­brown; antennae, palpi, and legs yellow­red.

Head broad (fig. 24) (MDL/OHW = 0.64– 0.66), dorsally flat, often with indistinct, transverse, medial crease; temporum short, forming rim at posterior margin of eye (fig. 24); head finely punctate, surfaces shiny and smooth between punctures; eyes large, rounded, finely faceted; frontoclypeal suture obsolete medially; clypeal margin strongly excavate (fig. 24); labrum anteromedially entire; antennomere ratios: length I:II:III = 2.2: 1.0:1.6, width VII:VIII:IX = 0.9:1.0:1.9. Pronotum broad (PNL/PNW = 0.59–0.61), laterally not strongly produced, lateral margins moderately broad, anterolateral angle subquadrate, posterolateral angle distinctive, but more rounded than anterolateral angle; punctation similar to that of head. Elytra moderately elongate (SEL/ELW = 0.99– 1.00); lateral margins broadly rounded; punctation coarser than pronotum, surface between punctures shiny and smooth, some punctures in indistinct series; sutural stria about one­half length of elytron. Mesosternum strongly concave posteriorly, with prominent lobe extending ventrally between mesocoxae, anterior portion much less than one­half length of posterior portion; medial longitudinal carina obsolete on anterior portion. Metasternum broad medially (MTL/ MTW = 0.30–0.31), slightly convex, setose; oblique carinae absent.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres moderately broad and with large ventral field of spatulate setae; mandibular horn, when present, very long, curving posteriorly over front of head, slightly flattened in cross­section, punctate and setose along its length, with very prominent apical fovea (figs. 23, 24) and very large series of fine, dense setae; frons with long, straight, pointed horn extending upward from surface at right of clypeus, apex reaching to near apex of mandibular horn (figs. 23, 24), some specimens with only a small prominence in this position, some specimens with no frontal horn or prominence but with mandibular horn, some specimens with no horns whatsoever; metafemur slender, unmodified; metasternal fovea anterior, large, transverse, curved, with large series of fine, dense setae. Median lobe in lateral aspect elongate, slen­ der, with small basal portion, curved basally, apical portion short, slender, slightly curved dorsad, apex narrowly rounded (fig. 71); in ventral aspect slender, lateral margins subparallel, slightly convergent in apical half, apical portion broadly triangular, apex narrowly rounded (fig. 70); operculum reduced to an inconspicuous, short, flattened structure that is apically bilobed (fig. 70); lateral lobes long, broadly fused along dorsal margin for about one­third length of median lobe, apices narrowly rounded, each with 2 long, stout setae (figs. 70, 71).

Female tarsi 5­4­4.

ETYMOLOGY: This species is named in hon­ or of Darlene Marie Platt, significant other of the junior author, for her encouragement and support.

DISTRIBUTION: This species is known from the Pacific Northwest east to Montana (fig. 91).

PARATYPES: CANADA: British Columbia: 5.6 mi E E Border Glacier NP on #1, 11 May 1984, FIT, RS Anderson (10, CNCI) ; Prospect Creek W Merritt, 27 Jun 1984 (1, QDWC) .

UNITED STATES: Oregon: Clackamas Co.: 1.5 mi S Jct US 26 Ore 35, 11 Jul 1975, 3500̍, conifer forest, Berlese, A Newton, M Thayer (8, MCZC) ; Mt Hood NF, Still Creek Cpgd, 10 Jul 1975, 3700̍, litter, mixed conifer forest, Berlese, A Newton (2, MCZC) .

DISCUSSION: The unusual horn arising from the right side of the frons of some male specimens (figs. 23, 24) is particularly unique to this species. Behavioral correlates of this particular morphology have not been observed. This species has been collected in conifer forests. Altitude records from label data are from 3500 to 5200 ft.

Figures

Figs. 17–30. Agathidium concinnum­ and A. pulchrum­group species, male heads showing left mandibular horn: 17, 18, A. mollinum: 17, left lateral; 18, dorsal. 19, 20, A. angulare: 19, left lateral; 20, dorsal. 21, 22, A. pulchrum: 21, left lateral; 22, dorsal. 23, 24, A. marae: 23, left lateral; 24, dorsal. 25, 26, A. aristerium: 25, left lateral; 26, dorsal. 27, 28, A. atronitens: 27, left lateral; 28, dorsal. 29, 30, A. picipes: 29, left lateral; 30, dorsal. Bars = 0.5 mm.

Figs. 70–85. Agathidium pulchrum­group species, aedeagus: 70, 71, A. marae: 70, ventral; 71, lateral. 72, 73, A. rotundulum: 72, ventral; 73, lateral. 74, 75, A. aristerium: 74, ventral; 75, lateral. 76, 77, A. atronitens: 76, ventral; 77, lateral. 78, 79, A. oregonense: 78, ventral; 79, lateral. 80, 81, A. picipes: 80, ventral; 81, lateral. 82, 83, A. hamulum: 82, ventral; 83, lateral. 84, 85, A. politum: 84, ventral; 85, lateral.

Fig. 91. Geographic distribution of Agathidium pulchrum­group species: A. aristerium = ^; A. marae = *; A. rotundulum = •.