Agathidium rusticum Fall, 1934b: 117

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 : 49-51

Agathidium rusticum Fall, 1934b: 117 .

TYPE MATERIAL: Holotype, Ƌ in MCZC labeled ‘‘N.H./Crawford Notch 9/25/08/ TYPE rusticum [‘‘rusticum’’ handwritten, red line

under ‘‘TYPE’’]/M.C.Z. Type 24044 [number handwritten, red label]/H.C. FALL COL­ LECTION’’.

TYPE LOCALITY: United States, New Hampshire, White Mountains, Crawford Notch.

DIAGNOSIS: This species differs from others in the group by having concolorous dorsal surfaces, the head and pronotum with prominent and distinct microreticulation consisting of fine, impressed lines forming small, isodiametric cells, antennomere VII large, 2 times length of VIII and distinctly wider (fig. 16), the male metasternal fovea large, transverse, located slightly anterad of middle, the median lobe relatively straight in lateral aspect, with small basal portion, the apex sharply pointed and strongly curved dorsad (fig. 67). The female has 4­4­4 tarsi.

DESCRIPTION: Body relatively small (TBL = 2.48–2.82 mm), robust (PNW/TBL = 0.45–0.52), laterally broadly rounded, moderately contractile.

Head red to dark red with large paler area medially, clypeus yellow; pronotum light red; elytra red to dark red; venter yellow to dark red; basal antennomeres red­yellow, club antennomeres brown; palpi yellow; legs yellow to yellow­red.

Head broad (fig. 9) (MDL/OHW = 0.55– 0.60), flattened, often with prominent transverse, medial crease; temporum very short, often forming distinct rim at posterior margin of eye; head finely punctate, with microsculpture of fine cells on surfaces between punctures; eyes large, rounded, finely facet­ ed; frontoclypeal suture moderately well defined medially; clypeal margin moderately excavate (fig. 9); anterior margin of labrum entire; antennomere ratios: length I:II:III = 1.6:1.0:1.3, width VII:VIII:IX = 1.3:1.0:1.5. Pronotum broad (PNL/PNW = 0.61–0.65) (fig. 16), laterally not strongly produced, anterolateral angle subquadrate, posterolateral angle distinctive, but rounded; punctation and surface microsculpture similar to those of head. Elytra robust (SEL/ELW = 0.87– 1.12); punctation coarser than pronotum, but sparse, surface between punctures shiny and smooth; sutural stria about one­half length of elytron on most specimens. Mesosternum strongly concave posteriorly, with prominent lobe extending ventrally between mesocoxae, anterior portion less than one­half length of posterior portion; medial longitudinal carina absent on anterior portion. Metasternum relatively narrow medially (MTL/MTW = 0.19–0.24), slightly convex, setose; oblique carinae absent.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres moderately broad and with small ventral field of spatulate setae; mandibular horn absent on most specimens, one specimen with left mandible thickened and extending up and slightly over right mandible; metafemur moderately slender, unmodified; metasternal fovea large, transversely linear and slightly curved, located slightly anterad of middle, smaller and rounded on some specimens. Median lobe in lateral aspect slender, evenly curved from base, basal portion not large, apical portion narrowed, apex slender and curved dorsad, pointed, in some specimens more distinctly hooked (fig. 67); in ventral aspect slender, lateral margins subparallel, apical portion with lateral margins slightly sinuate, convergent to narrowly rounded apex (fig. 66); operculum divided into two short, parallel, flat, truncate rami (fig. 66); lateral lobes long, slender, evenly curved, apices narrowly rounded with 2 long, stout setae (figs. 66, 67).

Female tarsi 4­4­4.

DISTRIBUTION: This species is known from northeastern North America (fig. 89).

SPECIMENS EXAMINED: CANADA: Ontario: Chaffeys Locks QUBS, 7 Sep 1980, forest, malaise FIT, S Peck (2, CNCI).

UNITED STATES: New Hampshire: White Mts SUBALPINE (1, MCZC). New York: Slide Mt, 3 Jun 1941, W Spector (1, CASC).

DISCUSSION: The antennae in this species approach the state found in many other non­ Agathidium Agathidiini where antennomere VII is distinctly longer and wider than VIII. However, in other respects, such as a distinctive temporum and postocular carina and excavate anterior clypeal margin, the species resembles other A. pulchrum group members.

Agathidium repentinum Horn

Figures 10 , 47 , 68, 69 , 90

Agathidium repentinum Horn, 1880: 304 ; Leng, 1920; Fall, 1934b.

TYPE MATERIAL: Holotype, ♀ in MCZC la­

beled ‘‘Wt Mts N. H. Woods/ HOLOTYPE 3024 [number handwritten, red label]/ A. repentinum Horn [handwritten]’’. Horn had a single specimen when he described this species and it is a holotype by monotypy.

TYPE LOCALITY: United States, New Hampshire, White Mountains.

DIAGNOSIS: This species differs from others in the group by having concolorous dorsal surfaces, the head and pronotum prominently and distinctly microreticulate, antennomere VII similar in size to VIII, the male metasternal fovea round, located slightly posterad of middle, the median lobe relatively strongly curved basally, with a very large basal portion, the apex sharply pointed, long, and straight (fig. 69), the male left mandibular horn, when present, consisting of a flattened, spine­ike process extending posterad over the clypeus. The female has 4­4­4 tarsi.

DESCRIPTION: Body moderately large (TBL = 2.67–2.85 mm), rotund (PNW/TBL = 0.44), laterally broadly rounded, moderately contractile.

Head, pronotum, and elytra dark red; venter dark red­brown to yellow­red; antennae yellow basally, apical 5 antennomeres brown; palpi yellow­brown; legs yellow­red.

Head broad (fig. 10) (MDL/OHW = 0.59– 0.66), dorsally flattened, without transverse crease; temporum short, forming distinct rim at posterior margin of eye (fig. 10); head finely and moderately densely punctate, surfaces between punctures with conspicuous microreticulation of fine, isodiametric cells; eyes large, rounded, finely faceted; frontoclypeal suture obsolete medially; clypeal margin slightly excavate, extending nearly to anterolateral margins of frons (fig. 10); labrum entire; antennomere ratios: length I:II:III = 2.1: 1.0:1.2, width VII:VIII:IX = 1.0:1.0:1.8. Pronotum broad (PNL/PNW = 0.63–0.65), laterally not strongly produced, anterolateral angle subquadrate, posterolateral angle distinctive, similar in form to anterolateral angle; punctation similar to that of head, with similar microreticulation. Elytra very broad and robust, lateral margins rounded (SEL/ ELW = 1.21–1.32); punctation slightly more coarse than on pronotum, but sparse, surface between punctures shiny and smooth; sutural stria about one­half length of elytron. Mesosternum strongly concave posteriorly, without prominent lobe extending ventrally between mesocoxae, anterior portion much shorter than posterior portion; medial longitudinal carina absent on anterior portion. Metasternum moderately broad medially (MTL/ MTW = 0.29–0.31), slightly convex, setose; oblique carinae absent.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres slightly expanded and with moderately large ventral field of spatulate setae; left mandibular horn when fully developed short, flattened, spinous, extending posteriorly over clypeus in adpressed fashion, without apical fovea, many specimens unmodified; metafemur moderately slender, unmodified; metasternal fovea submedial, moderately large, transversely slightly oval, with large brush of fine, dense setae. Median lobe in lateral aspect with large, robust basal portion and submedial constriction, slightly curved distal to constriction, moderately robust, apical portion long, straight, slender, tapering to long slender point (fig. 69); in ventral aspect moderately slender, lateral margins tapering gradually to broadly pointed apex (fig. 68); operculum a broad, rounded, hyaline lobe (fig. 68); lateral lobes slender, curved basally, apically narrowly rounded and each with 2 long, stout setae (figs. 68, 69).

Female tarsi 4­4­4.

DISTRIBUTION: This is a northern species collected from Alaska east to New Hampshire (fig. 90).

SPECIMENS EXAMINED: CANADA: Alberta: TP25Rg3 W5 mer, 14 Nov 1973, B and J Carr (1, CARR). Manitoba: Churchill, 15 Jun 1937, WJ Brown (2, CNCI). Yukon: Dempster Hwy, km 141 Blackstone River, 6 Jul 1985, mushroom traps in Sphagnum, SA Marshall (1, PECK).

UNITED STATES: Alaska: Denali NP, Reily Creek Camp, 10 Aug 1984, 1700̍, winter moose dung, taiga­willow forest, Berlese, S and J Peck (1, PECK) ; Nenana, 11 Aug 1984, riverside poplar forest litter, Berlese, S and J Peck (15, PECK). New Hampshire: Hermit Lake, White Mts , 6 Aug 1906, S Martin (1, MCZC) ; Subalpine, White Mts , 30 Jun 1896 (2, MCZC) ; Coos Co.: 1 mi NE East Inlet Dam , 26 Nov 1986, conifer leaf litter, DS Chandler (3, CNCI) .

DISCUSSION: Agathidium repentinum was described from a single female specimen. However, we are confident assigning male specimens to the species based on the pres­ ence of prominent microreticulation on especially the head and pronotum. The species is relatively rarely collected but is widespread across the northern latitudes. It has been collected from conifer and poplar forests and ‘‘taiga­willow forest’’, A single elevation record is from 1700 ft.

Figures

Figs. 3–16. Agathidium concinnum­ and A. pulchrum­group species. 3–15. Heads, dorsal aspect: 3, A. akallebregma. 4, A. hatchi. 5, A. concinnum. 6, A. laetum. 7, A. athabascanum. 8, A. columbianum. 9, A. rusticum. 10, A. repentinum. 11, A. rotundulum. 12, A. atronitens. 13, A. oregonense. 14, A. hamulum. 15, A. politum. 16, A. rusticum, left antenna, dorsal aspect. Bars = 0.5 mm, except fig. 16 bar = 0.25 mm.

Fig. 47. Agathidium repentinum, dorsal habitus.

Figs. 52–69. Agathidium pulchrum­group species, aedeagus: 52, 53, A. difforme: 52, ventral; 53, lateral. 54, 55, A. maculosum: 54, ventral; 55, lateral. 56, 57, A. pulchrum: 56, ventral; 57, lateral. 58, 59, A. amae: 58, ventral; 59, lateral. 60, 61, A. laetum: 60, ventral; 61, lateral. 62, 63, A. athabascanum: 62, ventral; 63, lateral. 64, 65, A. columbianum: 64, ventral; 65, lateral. 66, 67, A. rusticum: 66, ventral; 67, lateral. 68, 69, A. repentinum: 68, ventral; 69, lateral.

Fig. 90. Geographic distribution of Agathidium pulchrum­group species: A. amae = -; A. repentinum = •.