Margarinotus (Myrmecohister) maruyamai M. Ohara, 1999


Japanese name: Arikui-emma-mushi.
Type materials. Holotype (SEHU). Male. Point-mounted; labeled: 1. [Hokkaido] Maruyama, Sapporo, 8/vi/1998, M. Maruyama, (collected) from (a) nest of ant, Lasius sp. ; 2. Åâ; 3. Host ant, Lasius (Dendrolasius) fuliginosus (Latereille), det. M. Maruyama; 4. M. Ohara, No.-9889; 5. Holo-type, Margarinotus (Myrmecohister) maruyamai n. sp. Det. M. Ohara (red label). Paratypes (SEHU). Two males and 5 females. [Hokkaido] Same data as holotype (2 males and 2 females). [Honshu] Aomori-ken: Mt. Iwaki, Hirosaki (1 female, 3/x/1992, collected from a nest of ant, Lasius sp.), M. Ohara. Yamanashi-ken: Akenomura (2 females, 15/vi/1986), N. Haraki.


Description. Body oblong-oval, black. Biometric data are given in Table 1.
Frontal stria (Fig. 13A) absent. Disk of front feebly excavate anteriorly on each latero-median area, and densely and coarsely punctate, the punctures separated by 0.2­0.5 times their diameter and become finer along the margin. Labrum transversely oblong; the anterior half of disk depressed. Mandible stout and straight, the surface densely covered with fine punctures.
Pronotal side convergent forwards slightly on basal two-thirds, thence strongly arcuate and convergent apically. Apical angle rounded. Marginal of pronotum strongly carinate; the carination on anterior portion broad and inwardly acute at middle. Marginal pronotal, outer and inner lateral striae absent. Disk moderately convex medially, but strongly excavated on broad area along lateral and antero-lateral margins (Fig. 13B); surface densely and coarsely punctate, the punctures separated by 0.3­0.5 times their diameter and become shallower on lateral area.
Epipleural marginal stria clearly impressed on basal two-thirds, the basal end abbreviated anteriorly. Elytral marginal stria absent. Disk of epipleura feebly depressed along epipleural marginal stria, and densely covered with fine punctures that become denser and coarser outwardly. External subhumeral stria (Fig. 14A, B) complete and strongly crinate. Internal subhumeral stria wanting. First to fifth dorsal and sutural striae complete and strongly crenulate. Surface of elytra (Fig. 14C) densely covered with coarse punctures that are separated by 0.2 to 3 times their diameter; along the posterior margin the punctures sparsely and finely punctate.
Propygidium slightly convex on each lateral side (Fig. 13C); disk densely covered with large punctures, which are about twice as large as the punctures on elytra; fine punctures present on narrow area along posterior and anterior margins. Punctation of pygidium (Fig. 13D) similar to that of propygidium; the punctures become sparser and finer on apical area.
Prosternal lobe (Fig. 13E) convex medially; apical margin truncate; marginal stria impressed medially; disk of lobe sparsely covered with coarse punctures that are separated by 1 to 4 times their diameter and become denser anteriorly. Prosternal keel even on top; carinal striae impressed posteriorly and strongly crenulate; disk sparsely and coarsely punctate; lateral stria complete.
Anterior margin of mesosternum (Fig. 13F) feebly emarginate medially, its marginal stria distinctly impressed and carinate, but shortly interrupted at middle; disk sparsely covered with coarse and deep punctures that are separated by 0.5 to 2.5 times their diameter. Meso-metasternal suture well impressed and angulated at middle. Lateral metasternal stria extending obliquely and posteriorly, united with an oblique stria that inwardly extends from middle of the metasternal-metepisternal suture; lateral disk (Fig. 13H) densely covered with large, round and deep punctures with long hair, the punctures separated by 0.2­0.5 times their diameter and confused with each other on basal half. Post-mesocoxal stria of metasternum well impressed and carinate; intercoxal disk unevenly covered with coarse punctures that are separated by 0.3­2.5 times their diameter; interspace among the coarse punctures intermingled with fine punctures, these punctures become finer medio-posteriorly; narrow band along posterior margin without punctation.
Intercoxal disk of 1st abdominal sternum (Fig. 13G) completely striate laterally; sparsely and coarsely punctate, and intermingled with fine punctures among the coarse punctures; these punctures become finer medially.
Protibia (Fig. 14D, F) dilated, with weak 7 denticles on outer margin. Meso- and metatibiae strongly dilated.
Male genitalia as shown in Fig. 15; aedeagus slender; ratio of paramera length to basal piece length about 4.32.
Distribution. Japan (Hokkaido, Honshu).
Etymology. This species is named in honor of Mr. Munetoshi Maruyama of SEHU, who gave me the opportunity to study the specimens.
Biology. The present adult specimens were collected at entrances of nests of the ant Lasius (Dendrolasius) fuliginosus and observed to eat adults of the ant.

Histeridae/Histerinae/Histerini/Margatinotus/Myrmecohister/References