Tachyta (Tachyta) brunnipennis (W. J. MacLeay 1871)

Tachyta brunnipennis (MacLeay)

Bembidium brunnipenne MacLeay, 1873:118 [types probably in the MacLeay Museum or CSIRO, not seen by me; type-locality: Gayndah, South Queensland, Australia].

DIAGNOSIS.—The elytral chaetotaxy (Ed 6 in position b, i.e., in the fourth interneur, and Ed 3 located anterior of Eo 4), coarsely engraved microreticulation, and dense punctation of the dorsal surface are distinctive in the genus.

DESCRIPTION.—Form (Figure 32): Broad and much more convex than members of other species in the group.

Color: Dull rufous throughout; appendages flavotestaceous.

Head (Figure 53): Moderately broad and more convex than in T. umbrosa members, equal across eyes to width of pronotum across anterior angles; frontal furrows (Figure 53) more deeply impressed than in T. umbrosa members and with lateral carina better developed; front between eyes coarsely and sparsely punctulate, each puncture with well-developed seta, which is clearly visible in oblique view (50X); eyes very prominent. Mouthparts (Figure 52) as in T. umbrosa members.

Pronotum (Figure 54): Transverse, disc more convex and densely punctulate than in any other species of the group, punctures each with well-developed seta; sides moderately sinuate posteriorly, margins narrowly beaded, slightly reflexed; surface laterobasally with poorly developed carina (Figure 54); hind angles about right angles; basal transverse impression well engraved laterally, broadly interrupted medially; anterior angles not at all produced.

Elytra (Figures 55, 56, 60): As in T. umbrosa, members except interneurs less well developed, intervals flat; Ed 3 located anterior of Eo 4; recurrent groove and plica (Figure 56).

Microsculpture (Figures 57–59): Very coarsely engraved nearly isodiametric meshes with tendency toward longitudinal arrangement on pronotum and transverse rows on elytra.

Genitalia: Male (Figure 35) median lobe smaller and more arcuate than in T. umbrosa males and with more attenuated apex; internal sac also more arcuate yet with same light pigmentation (2 examined); female as in T. falli (5 examined).

Size: Length, 2.40 to 2.58 mm; width, 1.10 to 1.16 mm, 4 specimens measured.

VARIATION.—The width of the pronotum in relation to the width of the elytra is somewhat variable; in one specimen from Lockerbie, Queensland, both the elytra and pronotum are very narrow, although others in the same sample are normal.

NATURAL HISTORY.—MacLeay (1873) states that these beetles were found “on stony ground, and on the summit of a high hill remote from water.” This habitat is probably the result of wind drift during dispersal flights. All specimens available to me from MCZ were collected by Darlington. He states (1960) that all three of these localities are “light rain forest,” two of them in the lowlands and one, Ravenshoe, at 915 m. At the latter locale, Darlington collected in logs and I suspect that is where the beetles may be found. Adults were found in January and February; several of those labeled January are teneral.

DISTRIBUTION (Figure 61).—The range of this species extends from Port Darwin to the tip of Cape York peninsula in Australia; it is not known to reach New Guinea.

The malayica group

The members of the malayica group are characterized by the effacement of elytral microreticulation, elytral chaetotaxy with Ed 6 in position a (third interneur), and similarities of the male endophallus. Both species have members with more testaceous appendages and more rufous bodies than in the previous group.

One species has members found under bark; the other’s habitat is unknown.

The two species representing this group have a combined range extending from Malaysia south to New Guinea.