Bahía Blanca, Argentina.

Male, dry pinned, with labels as follows: “B. Blanca” / “708” / “Darwin Coll. 1885.-119.” / “Bahía Blanca, Argentina. C. Darwin.” / “?Trigonopselaphus A. Solodovnikov det. 2007” / “Holotype Darwinilus sedarisi Chatzimanolis des. Chatzimanolis 2013”. Darwin arrived on Bahía Blanca on September 6, 1832 and departed on October 17, 1832 according to Barlow (1967). The specimen was collected in September according to the Insect Notes that Darwin kept (Smith 1987). The holotype shows evidence of prior damage since several body parts have been reattached with non water-soluble glue. Deposited in BMNH. Paratype (1) male: Argentina, Córdoba, Río Cuarto, Breuer coll. (ZMHB).

As for the genus.

Body length 20.0–21.5 mm. Coloration of head and pronotum metallic green with blue-purple overtones near margins. Elytra light brown. Mouthparts, mesoscutellum, legs, abdomen and ventral surface of body dark brown-black. Antennae dark brown except antennomeres 4–7 appearing yellowish brown due to the presence of yellow microtrichiae. Head slightly transverse, width: length ratio = 1.23. Dorsal surface of head with uniform dense polygon-shaped microsculpture, small punctures interspersed and medium to large size punctures throughout except medially. Ventral surface of head with transverse microsculpture, micropunctures and few large punctures along borders of gula and directly posterior to mandibles. Antennomeres 1–3 longer than wide; antennomere 4 shorter but wider than 3; antennomere 5 narrower than 6; antennomeres 6–7 subequal in size; antennomere 8 slightly wider than 7; antennomeres 8–10 subequal in size; antennomeres 5–11 serrate. Pronotum width: length ratio = 1.08, widest medially; with uniform dense polygon-shaped microsculpture; small punctures interspersed and medium to large size punctures throughout except medial line; medium to large size punctures also present around margin of pronotum but not in rows as is typical in other Xanthopygina. Mesoscutellum with polygon-shaped microsculpture and uniform small almost confluent punctures. Elytra longer than pronotum; with dense polygon-shaped microsculpture and uniform punctation consisted of medium-sized almost confluent punctures; sutures of elytra with 2–3 rows of micropunctures on each side. Abdominal tergites with dense transverse microsculpture and uniform small-sized punctures; punctures almost confluent except punctation less dense medially on tergites III–IV. Sternum with uniform dense punctuation consisted of small punctures; additional irregular row of larger punctures near posterior margin on sternites V–VII; sternum with transverse microsculpture. Male secondary sexual structures: posterior border of sternite VIII having deep V-shaped emargination medially; sternite IX with shallow U-shaped emargination. Aedeagus as in Figs 8–9; paramere separated anteriorly into two lobes; lobes slightly asymmetrical; paramere much shorter and narrower than median lobe; paramere without peg setae; in dorsal view each paramere lobe converging to rounded apex; in lateral view paramere curved upwards. Median lobe in dorsal view wide, converging to rounded apex; with single large dorsal tooth; in lateral view median lobe curved upwards to prominent tooth, then becoming much narrower and slightly curved downwards to rounded apex.

The species is named in honor of Mr David Sedaris, a prolific writer, as an appreciation for his fascination with the natural world. I spent many hours listening to Mr Sedaris’ audiobooks while preparing the specimens and the figures for this and other manuscripts.

Known from Bahía Blanca, Buenos Aires and Río Cuarto, Córdoba in Argentina.

Unknown; the climate in the areas mentioned above is humid subtropical to humid temperate. However, agricultural fields have replaced the original habitat in these localities.

It is rather remarkable that only two specimens are known for such a large species. I have examined the rove beetle collections of most major museums in North America and Europe but unfortunately I was not able to locate any additional specimens. One explanation might be that this species lives in refuse piles of ants or other Hymenoptera (see below for further discussion).