Myrmecoagria hoebekei Eldredge, 2022

Eldredge, K. Taro, 2022, A new myrmecophilous genus of Falagriini from Colorado, USA (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 5165 (4), pp. 575-590 : 581-584

Myrmecoagria hoebekei Eldredge , new species

Holotype. ♂ ( MCZ): “ Florissant, Colo. / Expedition 1906. [“1906” crossed out]/ Coll. SA. XXX [illegible]/ No. July 16 07 [“ No. ” crossed out]//4097/det. A. Fenyes // M. rufa . nest of.//H. C. FALL /COLLECTION” ( Fig. 4 ).

Paratype. ♀ ( MCZ): “Florissant/Col./VI-2--07//953/det. A. Fenyes //H. C. FALL /COLLECTION//n. gen./near Zyras?” ( Fig. 3 ) .

Description. Body ( Figs. 1–2 ) approximately 3 mm (F = 3.072 mm, M = 3.008 mm) in length and ground color light reddish brown overall. Body without microsculpture asides from inconspicuous setal pores. Overall covered in short yellow microsetae with abdominal microsetae slightly longer, particularly at apicies. Macrosetae present on abdominal segments. Head: Head ( Fig. 2 ) reddish brown and transverse (HL / HW = 0.737 –0.750 mm; HL: F = 0.480 mm, M = 0.448 mm; HW: F = 0.640 mm, M = 0.608 mm); broadest slightly anterior of temples; broadly triangular in form; temples broadly rounded; vertex slightly broadly impressed; clypeus anteriorly slightly produced, shelf-like in lateral view; neck short and relatively broad (~ 1/3 HW); microsetae anterior of widest point directed medially to anteromedially; microsetae posterior of widest point directed medially to posteromedially. Eyes small (~ 1/4 HL), ovular, and directed anteroventrally. Antennae approximately 1 mm in length (F & M = 1.088 mm); antennomeres I–III elongate and subequal in length, IV–V longer than wide, VI–X subquadrate with successive articles gradually becoming shorter and broader apically, XI elongate and generally rounded, dorsal apex truncate and appearing asymmetrical in lateral view. Labrum ( Fig. 6 ) transverse with lateral margins broadly arcuate; median lobe broad, slightly produced distal of lateral lobes, fleshy with an irregular margin; macrosetae (AL, ML, BL) clustered approximate of apicolateral margin; ɑ robust, sublate seta-like in form and arising from labral surface; β small, peg-like, and arising between medial lobe and cybarial epipharyngial surface; ε setate and arising between medial lobe and cybarial epipharyngial surface; ɣ large, peg-like, and arising from cybarial epipharyngial surface; anteromedial sensory area with several pairs of cup-like sensillae; medial pore field with a vertically clustered group of relatively large pores, with several bi-porous pores, a sclerotized ridge present apicolaterally; boarder region with distal cluster of teeth-like protruding sculpturing, transitioining posteriorly into blunt, scale-like sculpturing and into small denticles in the basal region; several pored pores scattered vertically along boarder of border- and mesolateral regions; mesolateral region with sparse denticulate sculpture apically with vertical rows of scale-like denticles posteriorly; basolateral region with a apicolateral cluster of long spiculate sculpture with several scattered shorter spiculae adorally; transverse row distinct; cibareal plates weakly sclerotized with a single large pore in the medial proximal group, several transverse rows of longitudinal sculpturing present. Mandibles ( Fig. 7 ) triangular, right tooth with molar tooth; apical tooth acute and curved adorally; prominent marginal subapical serration present; prosthecal S1 with setate setulae, S2 with acute denticulate setulae, S3 with setulae transitioning from denticulate to blunt productions proximally; dorsal prosthecal surface with acute denticulate setulae at S2 and small denticulate field at S3; molar lamina weakly developed; dorsal molar region with faint granulose texture; dorsal discal pore field with scattered small and one large pore; scrobe with numerous setae. Maxilla ( Fig. 8 ) galea shorter than lacinia; lacinia blunt with moderately produced membranous medial lobe; distal spine blunt; S1 with overlapping narrow teeth clustered distally proximal of distal spine; S2 with two distinct well-spaced isolated spines; S3 with both dorsal and ventral trichae on medial lobe surfaces; dorsal setal column distinct; basigalea relatively large and prominent; distigalea with S1 truncate at aboral margin, distal lobe with a single basal seta and weakly produced with short scattered apical trichae; S2 with slightly apically directed pallisade trichae. Labial complex ( Fig. 9 ) mentum transverse, widened at base, basal margin broadly arcuate, u-v-w clustered at apicolateral corner; prementum transverse with broad lateral apodemes, real pores paired, distal setae separated by width of setal pore; palps with three articles, I longer than wide with adoral apex truncate, II transverse and short, III blunt and almost twice as long as II; I with setulae ɑ and ɣ present, setae a-d, f and h present, a single twin pore present; II with setae e and g present, two separated median pores present ventrally; III with a single mammiform sensilla; glossa ~ 1/3 longer than wide, apical ~ 1/3 split, median pores prominent; small paired setae present near distal end on dorsal surface. Prothorax: Pronotum ( Fig. 2 ) reddish brown and transverse (PL / PW = 0.727 –0.762; PL: F & M = 0.512 mm; PW: F = 0.704 mm, M = 0.672 mm) and generally sub-rectangular in form; anterior margin broadly slightly anteromedially produced; anterior corners broadly rounded; lateral margins posteriorly slightly sinuate; posterior angles obtusely sub-angulate; posterior margin slightly rounded; disc with a faint medial longitudinal sulcus that fades distally; anterior corners deflected ventrally, hypomera anteriorly prominent in lateral view, gradually becoming strongly inflexed posteriorly; marginal bead extremely faint, most prominently posteriorly and becoming faint anteriorly. Prosternum narrow and process acutely slightly produced between procoxae. Legs, FF: F = 0.576, M = 0.512; FT: F = 0.512, M = 0.480; tarsomeres I–III subequal in length, IV longer; macrosetae absent. Mesothoracic peritreme sclerites relatively small, narrowly produced laterally and not contiguous at midline or with pronotal hypomera. Meso-metathoracic complex: Elytra yellowish and transverse (EL / EW = 0.667 –0.640; EL: F = 0.544, M = 0.512; EW: F = 0.640, M = 0.768); longest at posterolateral angles; posterolaterally acutely sinuate; apical margin arcuate towards midline and shortest at suture. Scutellum simple and triangular in form. Mesothorax slightly shorter than metathorax; prepectus slightly deflected ventrally with a pair of carinae extending slight posteromedially; mesosternal process acute, angulate and extending to middle, slightly ventral of metasternal process; metasternal process acute and roundly produced, extending shy of middle, smoothly sloping off laterally into acetabulae; isthmus narrow; marginal bead absent. MF: F & M = 0.608 mm; MT: F & M = 0.608 mm; HF: F = 0.672 mm, M = 0.640; HT: F & M = 0.672 mm. Abdomen overall more or less parallel-sided and slightly narrowing distally; length ~ 1.5 mm long; III–IV reddish brown with V–VIII blackish. FT8 ( Fig. 11 ) narrowing distally; apicolateral margins slightly produced acutely; apical margin strongly sinuate with middle arcuate produced; four pairs of macrosetae present, arranged in two rows; microsetae short and uniformly present, slightly longer along apical margin. FS8 ( Fig. 12 ) broadly rounded and narrowing distally; margin slightly concavely incised apicomedially; macrosetae unevenly present in vague rows; longish microsetae scatted throughout, slightly longer along midline. MT8 ( Fig. 13 ) subquadrate; apical margin slightly sinuate; four pairs of macrosetae present, arranged in two rows; microsetae short and uniformly present, slightly longer along apical margin. MS8 ( Fig. 14 ) broadest at base and unevenly narrowing distally; lateral and apical margins sinuate; apical margin strongly triangularly produced medially; macrosetae unevenly present in vague rows; longish microsetae uniformly distributed, slightly longer along apical margin.

Spermatheca ( Fig. 10 ) tightly S-shaped; apex bluntly produced; cone weakly produced; membranous zone wide and prominent; proximal end tightly curled atop itself; surface covered in transverse somewhat reticulate sculpturing. Aedeagus: Median lobe ( Figs. 15–16 ) with basal capsule more or less evenly rounded and apical lobe produced and more or less evenly narrowing apically; proximal apodeme significantly covering the base of compressor plate; distal apodeme narrow and prominently present; foramen subcircular and moderately sized; proximal costa long and fading proximally, narrowly visible in lateral view; distal crest strongly produced in lateral view, median costa apically produced and fused with arcuate costae basally; a U-shaped sclerite present at base of distal crest and partially obscuring foramen paramerally; longitudinal bands prominent with a sclerotized proximal portion; copulatory piece subulate in parameral view, apically pointed and slightly produced, tapering towards base, sinuate in lateral view, annulus ribbed and present subapically; internal sac adorned by a pair of numerous rows of sclerotized teeth present lateral of the copulatory piece. Paramere ( Fig. 17 ) deep; paramerite broadly V-shaped; apical paramerite 1/2 length of basal paramerite; paramerite strongly hooked at base; medial- and accessory phragma fused to paramarginal phragma, accessory + paramarginal phragma strongly acutely produced both distally towards apical marginal phragma and proximally to meet condylite; hinge zone large and membranous area C-shaped; intervelar patch irregularly surrounding hinge zone; intervelar sclerite large and meeting apical marginal- and velar phragma apically and intervelar patch basally; all marginal phragma relatively narrow; apical lobe arrowhead-shaped and truncate apically, articulating with distal deflected portion of the velar phragma, two pairs of macrosetae and numerous pores present; paramerite vellum separated from condylite vellum, elongate, and with elongate pleated creases; condylite narrowly elongate, with strong phragma development at base, distinctly articulating with paramerite, with a distinct elongate narrowed condylte vellum at apex, with several elongate creases and a granulate textured area at base; paramerite- and condylite vellums connected by a thin membrane.

Distribution. Known only from Florissant, Colorado, USA.

Host. The female was mounted together with an ant specimen subsequently identified as Myrmica incompleta ( Fig. 5 ). Presumably the female was collected with M. incompleta and represents a host record as is customary ( Fig. 3 ). The male specimen had a label reading “ M. rufa . nest of” pinned to it ( Fig. 4 ). It is unclear what species this label is in reference to. It may be a misspelling in reference to the introduced Myrmica rubra , a Palearctic species, which is still limited to parts of the east and west coasts. Presumably, given the specimen and label data available, Myrmecoagria hoebekei is a symbiont of Myrmica ants, with Myrmica incompleta serving as a host species.

Etymology. This species is dedicated to a mentor, E.R. Hoebeke who inspired me to study Aleocharinae and whose timeless revision of North American Falagriini contributed to our foundational understanding of North American aleocharine systematics. The name is possessive.

Figures

FIGURE 6. Labral complex, ventral, paratype female.

FIGURE 17. Paramere, internal, holotype.

FIGURES 1–5. (1) Habitus of Myrmecoagria hoebekei, male holotype. (2) Head and pronotum of Myrmecoagria hoebekei, male holotype. (3) Paratype labels, female. (4) Holotype labels, male. (5) Habitus of host pinned with paratype female.

FIGURES 7–8. (7) Right mandible, dorsal, paratype female. (8) Right maxilla, ventral, paratype female.

FIGURES 9–10. (9) Labial complex, ventral, paratype female. (10) Spermatheca, paratype female.

FIGURES 11–14. (11) Female tergite VIII, paratype. (12) Female sternite VIII, paratype. (13) Male tergite VIII, holotype. (14) Male sternite VIII, holotype.

FIGURES 15–16. (15) Median lobe, lateral, holotype. (16) Median lobe, parameral, holotype.