Tasmanitachoides baehri sp. nov. Figures 10E, 15D, 17B, 18A, 19A, 20A, 21

Material examined.

Holotype. Male (ANIC), labeled: " Australia: ACT: Murrumbidgee River, 0.15 km u/s Uriarra Crossing (35°14.717'S, 148°57.135'E 440 m) Washed fr. gravel/under cobbles at river edge. N. Porch, 28 Sep. 2002 ", " David R. Maddison DNA5569 DNA Voucher" [pale green paper], " HOLOTYPE Tasmanitachoides baehri Maddison & Porch" [partly handwritten, on red paper]. Genitalia mounted in Euparal on coverslip pinned with specimen; extracted DNA stored separately. GenBank accession numbers for DNA sequences of the holotype are MW291166, MW291260, MW291213, and MW291304.

Paratypes (26). Same label data as holotype (8; ANIC, OSAC). ACT: Murrumbidgee River, 0.15 km u/s Uriarra Crossing (35°14.717'S, 148°57.135'E 440 m). Washed fr. gravel/under cobbles at edge of river. N. Porch, 14 Oct. 2000 (10; NPC, ANIC, ZSM, NMV, NHMUK, MCZ). ACT: Murrumbidgee River, 0.15 km u/s Uriarra Crossing (35°14.717'S, 148°57.135'E 440 m). Washed fr. gravel/under cobbles at edge of river. N. Porch, 28 Sep. 2002 (8; NPC, ANIC, ZSM, NHMUK, MCZ) .

Other material examined.

We have seen an addition specimen labeled “Paddy’s River, 1 mi. S. of Cotter Dam, ACT, 17.iv.1969. S. Misko" (ANIC; currently in ZSM).

Type locality.

Australia: ACT: Murrumbidgee River, 0.15 km u/s Uriarra Crossing (35°14.717'S, 148°57.135'E 440 m).

Derivation of specific epithet.

We are honored to name this species after the late Martin Baehr, who discovered and documented many of the carabid species of Australia, and who described 14 of the known species of Tasmanitachoides .

Diagnosis and description.

Very small, length 1.59-1.63 mm (n = 4). A pale species, body mostly orange, with the front half of the elytra and head a darker reddish orange. Antennae pale testaceous, with antennomeres 5-11 slightly infuscated. Head with moderately long but shallow frontal furrows, reaching approximately the center of the eye, and at least to the anterior supraorbital seta (Fig. 17B); with a groove extending from anterior supraorbital puncture anteriad and mediad to approximately halfway toward the frontal furrow (Fig. 17B). Pronotum convex, narrow, only slightly wider than head (Fig. 10E). Hind angle of pronotum obtuse. Elytra more parallel-sided than T. wilsoni . Striae 2 and 3 shallow, broad, impunctate grooves (Figs 15D, 18A); nearby intervals convex. Stria 5 deeply engraved in anterior half of elytron; stria 5 reaching or nearly reaching the second discal seta (ed5; Fig. 15D). Striae 6 and 7 effaced. Discal setae ed6 apparently in stria 2. Microsculpture without engraved lines; where present on the dorsal surface, the microsculpture is formed as low papillae without defined boundaries (Fig. 18A). Pronotum and head very shiny, virtually without microsculpture. Aedeagus (Figs 19A, 20A) with internal sac sclerites compact, and sinuate, very similar to those of T. wilsoni (Fig. 19B).

Comparison with related species.

Likely to be confused only with similarly small and compact T. wilsoni, from which it can be distinguished by the narrower pronotum with less rounded lateral margins, and narrower, less rounded elytra. In addition, T. wilsoni has much shorter frontal furrows, which do not reach the anterior supraorbital seta (Fig. 17A); T. wilsoni also lacks the notable groove extending forward from the anterior supraorbital seta. The elytral striae in T. wilsoni are less evident than in T. baehri: T. baehri has an evident (if shallow and broad) stria 3 between the two anterior discal setae (Figs 15D, 18A), whereas in T. wilsoni it is either absent or extremely faint and shallow (Fig. 15C); stria 5 in T. wilsoni is much shorter, only reaching to around half-way in between the two anterior discal setae (Fig. 15C), as opposed to reaching or nearly reaching the second discal seta (ed5) as it does in T. baehri (Fig. 15D) T. baehri and T. wilsoni look very much like small members of the tribe Tachyini (e.g., Elaphropus, Tachyura). The two Tasmanitachoides can be distinguished by the presence of four setae on the clypeus, as opposed to the two setae present in tachyines.

Geographic distribution.

Only known from the Australian Capital Territory (Fig. 21), but very likely occurring in similar habitats in NSW.

Habitat.

Collected from pockets of gravelly cobble at the edge of still water of the Murrumbidgee River. The collection locality was amongst riverbank sheoaks ( Allocasuarina) and relatively protected. Specimens were recovered by splashing the gravel bank after removal of cobbles. The species was collected with T. murrumbidgensis, T. rufescens, and a single specimen of T. leai .

Phylogenetic relationships.

This species belongs to the Tasmanitachoides kingi species group and appears to be sister to T. wilsoni among the sampled species (Figs 5 - 9).

Notes.

This species was called " Tasmanitachoides cf. rufescens " in Maddison et al. (2019).