Lissomus punctulatus Dalman, 1824: 14 (designation of Fleutiaux 1947: 138).

Genus synonymies and an historical nomenclatural bibliography for Lissomus were given by Johnson (2021) and these citations are not repeated here.

The body is moderate in length, about 6–16 mm; dorsum shallowly to strongly convex, venter shallowly convex. Integument smooth, shining between fine to moderate-sized punctures; each puncture with either a minute seta on pronotal and elytral discs, appearing glabrous, or seta long, thin, hair-like especially venter and lateral areas of pronotum and elytra. Antennal insertion deep, transverse; antennomere 2 subcylindrical, 3 subserrate; 4–10 moderately to strongly serrate, 11 oval to lachrymiform. Hypomeron excavate posteriorly to receive front legs, posterior margin a thin perpendicular lamelliform wall; pronotosternal margin anterior deeply and obliquely fossate to receive antenna. Mesoventrite with deep median fossa, broadly U- to V-shaped, walls planar, to slightly below or slightly elevated to metaventrite; anterior angles formed as crural impressions to receive mesothoracic legs, usually with an arcuate carina from mesocoxal margin directed laterally, reaching partly or completely to lateral margin. Tarsomeres 1–4 with progressively enlarging ventral membranous lobes, rarely with tarsomere one with densely setose ventral pad only. Morphologically the sexes are not distinguishable without examination of genitalia.

Holotype • female, labelled: DOMINICAN REPUBLIC, 700 m, Pedernales Province, 18°06'24.5"N, 71°37'12.5"W, 11.v.2024, leg. J. Pirkl & J. Hodecek (MCSN-VD).

Paratypes (n = 4) • females, labelled: DOMINICAN REPUBLIC, Monseñor Nouel Province, 9.2 km W of Rt. 1 (Autopista Duarte) on Constanza Rd, 28.vi.1999, blacklight trap, leg. R. Woodruff & R. Baranowski (1, FSCA); • Río Blanco, Hydroelectric Dam, 613 m, 13.v.2001, blacklight trap, leg. R. Woodruff & C. Nuñez (1, FSCA); • Bonao, La Presa, 13.v.2001, leg. C. Nuñez & H. Matsuzawa (1, MNHNSD); • Puerto Plata Province, 610 m (2000 ft), La Cumbre de Puerto Plata, 8–9. v.1985, leg. E. Giesbert (1, USNM).

Lissomus arawak is immediately recognized in the Hispaniolan fauna by the combination of the shining and seemingly glabrous black integument; pubescence short, pale, hair-like; slightly inflated dorsal silhouette at midlength, strongly convex dorsum; smooth and indistinguishable elytral striae and intervals; pale yellow antennomeres 3–10 contrasting with the black body; the anterior pronotal angles appearing constricted at a smooth bulging termination of a carina; and a deep stria 9 sulcus separated from humeral sulcus by a trans-sulcal carinate bridge; elytral humeri as polished bosses; lateral margins carinate basally, generally flattened, smooth, polished, contiguous with epipleuron apicad.

Body (Figs 1, 2, 3) length 7.9–9.0 mm, width 4.4–4.8 mm; broadly arcuate laterally, subparallel at midlength to slightly inflated past midlength, strongly convex dorsally. Integument shining, dark red-black to black. Antennomeres 4–10 translucent pale yellow. Tarsi red-yellow. Pubescence short, pale, fine and hairlike, appressed, directed posteriorly, except directed anteriorly on head.

Head evenly convex on sparsely punctured vertex; frons sparsely to moderately-densely punctured forming irregular patches in triangular impression, punctures separated by 1–3 times their own diameter. Ocular index 65–66. Antenna moderately serrate; antennomeres 1–3, base of 4, and 11 infuscate, to variably yellow on 4–10; antennomere 2–11 length ratio 1.0:1.0:1.2:1.3:1.3:1.3:1.5:1.5:1.5:2.5, with antennomere 11 exceeding length of pronotosternal suture.

Pronotum with median length 0.44 times width at basal margin across posterior angles, 0.3 times length of elytron; punctures on disc simple, deep, separated by ca. 2–4 times own diameter, becoming denser antero- and posterolaterally. Anterior margin bisinuate; anterior angles extended, impressed preapically. Lateral margin carina polished, upturned at anterior angle; hind angles slightly incurved apically, dorsal carina short, obtuse, evanescent anteriorly, reaching 0.4 times distance to anterior margin. Posterior margin with deep ante-scutellar emargination flanked by triangular extensions held against scutellar shield. Hypomeron short, subtriangular, sparsely-deeply punctured, deeply fossate posteriorly to receive front legs. Pronotosternal suture deeply invaginated to receive antenna in repose.

Scutellar shield length 1.1 times width, subpentagonal obovate, strongly convex anteriorly, moderately convex posteriorly, moderately punctured.

Elytra length 3.4 times median length of pronotum, deplanate apically. Humeri of strongly convex bosses, each with mesad impressions; striae 1–8 and intervals obsolescent, with small, sparse, subserial punctures. Humeral sulcal bridge carinate, separating humeral groove from lateral sulcus. Stria 9 sulcus deep basally and merging with humeral groove, becoming progressively shallower apically, with costal margin of sulcus with obsolescent carina from metafemoral notch to end. Epipleuron shallowly, sparsely punctured, posthumeral lateral margin carina fine, forming lateral edge of sulcus; merging with marginal interval apicad of sulcus.

Prosternum moderately convex anteriorly, disc sparsely punctured; chin piece short, sharply deflexed. Posterior process short, median smooth, impunctate, not margined; laterally coarsely punctured. Mesoventrite short, with deep U-shaped median fossa; lateral walls thin, ridge-like; posterior margin coplanar with metaventrite. Metaventrite 2.2 times wider than median length, disc punctures sparse, shallow, separated 2–4 times own diameter, slightly denser anterolaterally; with deep anterolateral impression with arcuate carina extending along posterior margin ca. 0.3 times distance toward anterolateral angle. Metacoxa short, narrow, sinuate posteriorly. Metatarsomeres with 1–4 progressively shortening; tarsomere 1–5 length ratio 1.00:0.34:0.31:0.28:1.13.

Abdomen with ventrites moderately-densely punctured, most punctures separated by 0.5–1.0 times own diameter. Ventrites 1–4 with long, pale golden, hair-like setae forming a median patch; shorter setae laterally each ventrite 1–4, and ventrite 5 entirely setose. Ovipositor (Fig. 4) length 4.3 mm, extending into metathorax when retracted; stylus subapical and lateral on coxite, reduced to single seta; coxite subtriangular, narrowing apically, shallowly excavate dorsally, shallowly emarginate along medial margin; baculus dorsoventrally compressed, broadening anteriorly, 4.0 times longer than coxite. Oviduct and vagina simple, tubular. Bursa copulatrix (Fig. 5) globular, exterior corrugated, with four internal sclerotized spines; spermathecae of two intertwined lightly sclerotized, narrow, coiled ducts.

Males not known. Throughout Lissomus males are not distinguishable from females without examination of genitalia (Johnson 2021, 2022).

The specific epithet arawak, a noun in apposition, is after the Arawak culture of indigenous peoples that lived on Hispaniola and other Antillean islands prior to 16^th century colonization.

Hispaniola, Dominican Republic, provinces of Monseñor Nouel, Pedernales, and Puerto Plata (Fig. 6).

Collection dates from early May to late June may suggest a primary adult activity period during the early rainy season. The type locality for L. arawak is in the Sierra de Bahoruco of Provincia de Pedernales, in the southwestern region of the country. This area is part of the Bahoruco-La Selle region that contains the highest diversity of endemic plants on Hispaniola (Cano-Ortiz et al. 2016). The holotype was collected at an elevation of 700 m in a mixed, dense forest along the Alcoa Road leading from the Las Mercedes bauxite mine toward Sierra de Bahoruco National Park (Fig. 7). The vegetation at the collection site includes a mix of broadleaf species, that progressively transition from the dry broadleaf forest of lower elevations into the endemic pine (Pinus occidentalis Sw. (pino criollo; Pinaceae)) dominated forest at higher elevations. Other notable plant species observed at the site include Dodonaea viscosa Jacq. (broadleaf hopbush; Sapindaceae), the endemic shrub Poitea galegoides Vent. (Fabaceae), the endemic Narvalina domingensis (Cass.) Less. (Asteraceae), and a Rhytidophyllum sp. (Gesneriaceae) (J. Hodecek, pers. obs.). The La Cumbre area of Provincia de Puerto Plata in the north of the country is in the Cordillera Septentrional, this northern-most range on the island is geologically youngest and has the highest montane rainfall on Hispaniola with magnolia forests (Cano Carmona et al. 2010; Cano-Ortiz et al. 2016). One specimen is from the Río Blanco area southwest of Bonao and a second from a high montane area along DR-12, the Carretera de Constanza highway, both sites in Monseñor Nouel Province. All known sites are in mesic tropical montane broadleaf forest or pine transitions, including cloud forest. Such natural habitats of the island remain biologically diverse in plants and animals (Schubert 1993; Martin et al. 2004; Cano-Ortiz et al. 2016) yet are heavily fragmented and surrounding areas are now dominated by secondary forests.

Lissomus arawak is most similar in morphology to members of the Lissomus gagatinus Bonvouloir, 1859 group, known from Costa Rica to Colombia, east to Guyane, and north to Guadeloupe (Chassain and Touroult 2012), and including Lissomus impressifrons Bonvouloir, 1859. The obsolescent elytral striae and intervals with sparse, fine punctation are character states shared with that group. The intermediate antennomeres and tarsomeres are pale, as in L. impressifrons from Guadeloupe, although L. arawak differs in body form and details of sculpture. Cobos (1967) associated L. insularis with these same mainland species, whereas L. arawak differs from them in having more strongly domed elytra, stronger humeral bosses, subparallel lateral margins in dorsal view, and yellow intermediate antennomeres. This new species is morphologically distinct from L. quisqueya and L. woodruffi (Johnson 2022), indicating a probable second intrageneric lineage of these beetles in the Greater Antilles.