Microlia tetramera Gusarov

Gusarov, Vladimir I., 2002, A revision of the genus Microlia Casey, 1910 (Coleoptera: Staphylinidae: Aleocharinae: Hoplandriini), Zootaxa 34, pp. 1-24 : 19-21

5. Microlia tetramera Gusarov , sp. nov. ( Figs. 17­18, 62­76 )

Type material. Holotype:, COSTA RICA: San Jose, Zurquí de Moravia, 1600m, malaise (P. Hanson), iii.1994 ( KSEM).

Additional material: COSTA RICA: possible females of M. tetramera , type A: 3, same data as the holotype but vi­vii.1994;, ditto but vi.1993 ( KSEM); possible females of M. tetramera , type B: 2, as the holotype but ix­x.1993 ( KSEM).

Diagnosis (based on the male holotype only): Microlia tetramera can be distinguished from other species of Microlia by having mesotarsus with 4 segments, the lateral angles of male tergum 3 extended posteriorly as pointed triangular lobes ( Fig. 76 ), by the shape of the aedeagus ( Figs. 68­72 ), particularly the hook­like apical process of median lobe ( Figs. 68­69 ).

Description (based on the male holotype only): Length 1.8 mm. Head, pronotum and abdominal tergum 3 brownish yellow; elytra brown, with lighter humeral angles; abdominal segments 4­7 dark brown; legs, mouthparts and seven basal antennal segments yellow; four apical antennal segments brown.

Head surface mat, on disk with strong isodiametric microsculpture, puncturation fine, distance between punctures equal to their diameter. Eyes 2.8 times longer than temples.

Pronotum strongly transverse, 1.4 times wider than head, width 0.50 mm, length 0.30 mm, width to length ratio 1.7; surface mat, with strong isodiametric microsculpture; puncturation as on head. Elytra wider (0.60 mm) and longer (0.47 mm, measured from humeral angle) than pronotum (pronotal length to elytral length ratio 0.64), 1.3 times wider than long, surface glossy, with weak transverse microsculpture, puncturation stronger than on pronotum and slightly asperate, distance between punctures equal to their diameter. Mesotarsus with 4 segments.

Abdominal terga glossy, without visible (at x70) microsculpture, with fine puncturation, distance between punctures 2­3 times their diameter.

Lateral angles of male tergum 3 extended posteriorly as pointed triangular lobes ( Fig. 76 ). Male tergum 7 without tubercles. Posterior margin of male tergum 8 crenulate ( Fig. 63 ). Posterior margin of male sternum 8 with broad triangular lobe ( Fig. 62 ). Aedeagus as in Figs. 68­72 . Apical process of median lobe in lateral view bent like hook ( Figs. 68­69 ).

Discussion: Two types of females, apparently representing different species, both with tarsal formula 4­4­5, have been collected at the type locality of M. tetramera . The females of the type A have thicker spermatheca with two coils and pointed capsule ( Fig. 73 ) while in the type B females the spermatheca has about five coils and rounded capsule ( Fig. 74 ). The male holotype of M. tetramera differs from both types of females in having darker coloration, stronger microsculpture of head and pronotum. It is impossible to reliably associate the male holotype with one of the two types of females without having additional material. An alternative hypothesis, that the type B females are conspecific with M.

pentamera (tarsal formula 4­5­5), seems implausible because no intraspecific variation of tarsal formula was observed in other species of Microlia .

Distribution: Known from a single locality in Costa Rica ( Fig. 80 ).

Natural History: Microlia tetramera was collected with malaise trap.

Figures

FIGURE 80. Geographical distribution of Microlia Casey. 1 – M. silacea (Erichson); 2 – M. meticola (Casey); 3 – M. azteca (Casey); 4 – M. pentamera Gusarov, sp. nov.; 5 – M. tetramera Gusarov, sp. nov.; 6 – M. panamensis Gusarov, sp. nov.

FIGURES 62 ­ 67. Details of Microlia tetramera Gusarov, sp. nov. (62 ­ 63 – holotype; 64 ­ 67 – possible female of M. tetramera from Costa Rica, 64 ­ 65 – type A, 66 ­ 67 – type B). 62 – male sternum 8; 63 – male tergum 8; 64, 66 – female sternum 8; 65, 67 – female tergum 8. Scale bar 0.2 mm.

FIGURES 68 ­ 76. Details of Microlia tetramera Gusarov, sp. nov. (68 ­ 72, 75 ­ 76 – holotype; 73 ­ 74 – possible female of M. tetramera from Costa Rica). 68 – median lobe of aedeagus, lateral view; 69 – apex of median lobe of aedeagus, lateral view; 70 – median lobe of aedeagus, ventral view; 71 – apex of median lobe of aedeagus, ventral view; 72 – apex of median lobe of aedeagus, apical ventral view; 73 ­ 74 – spermatheca; 75 – apical lobe of right paramere, internal view; 76 – abdominal segment 3, dorsal view. Scale bar 0.2 mm (68, 70, 73 ­ 74), 0.1 mm (69, 71 ­ 72, 75), 0.55 mm (76).