The Desmopachria convexa group is characterized in the genus by an articulable subapical process on the male lateral lobe of the aedeagus and the male median lobe either apically bifid (e.g., Fig. 15) or trifid (e.g., Fig. 11) with the exception of D. pilosa Miller (apically simple, Fig. 52) and D. majuscula Young (seemingly absent, Fig. 34). The species are extremely similar to each other in external appearance, though there are some diagnostic variations in size, shape, punctation and coloration. But externally there are often few particularly useful characters for distinguishing closely related species. Males and females are externally extremely similar, as well.

There are two apparent subgroups in the D. convexa species group, those with a smaller subapical articulable appendage on the lateral lobe not extending beyond the truncate apex (e.g., Figs 4, 5) and those with a larger subapical articulable appendage that is leaf-like and extends well beyond the elongate, slender oblique apex of the lateral lobe (e.g., Figs 9, 10). These are referred to here as the D. convexa-convexa subgroup (with the larger subapical articulable appendage) and D. convexa-signata subgroup (with the smaller subapical articulable lobe). Desmopachria convexa-convexa species are found in North and Central America and the Caribbean, and D. convexa-signata species are found in South America. It is not clear at this time how these two groups might be related to each other or their monophyletic status, but they seem to be well-characterized by the shared articulable appendage of the male lateral lobes which is unique in Desmopachria and Dytiscidae in general.

This group corresponds to the Desmopachria convexa-grana group of Young (1980), which he later revised (Young 1981). Additional new species were described by several investigators (Braga and Ferreira-Jr. 2010; Miller 2001; 2005; Young 1990).

It is possible that several other described species may belong to this species group including D. attenuata Régimbart, 1895 (Young 1980), D. balfourbrownei Young, 1990, D. striga Young, 1990, and D. subfasciata Young, 1990 based on illustrations suggesting the presence of a subapical or apical articulable structure on the lateral lobe (Miller 2001). These species have not been well-described making the diagnostic characteristics of the group hard to discern. It does not appear that these species correspond with either of the new species described here, however.

Guyana, Region IX, Parabara, trail to mines, 2°05.095'N, 59°14.174'W, 250m.

Holotype in CSBD (currently in KUNHM, see above), male labeled, “Guyana: Region IX 2°05.095'N, 59°14.174'W, 250 m Parabara, Trail to mines detrital pools in forest leg. Short, Isaacs, Salisbury 2.xi.2013; GY13-1102-01A/ SEMC1271259 KUNHM-ENT/ Holotype Desmopachria manco Miller, 2020 [red label with black line border].” Paratypes, 1 labeled, “Guyana: Region IX 2°52.204'N, 59°55.003'W, 124 m nr. Kusad Mts., marshy area leg. Short, Isaacs, Salisbury 27x.2013; GY13-1027-01A/ SEMC1271270 KUNHM-ENT [barcode label]/ Paratype Desmopachria manco Miller, 2020 [blue label with black line border].”

The paratype specimen was not dissected but it has the same color pattern, size, and other features as the holotype. It is assigned to this species even though it is from some geographic distance away.

This is an extremely small species among Dytiscidae and even among Desmopachria (Fig. 1; TL = 1.2–1.3 mm). The dorsal diffuse maculae on the elytra are characteristic (Fig. 1). The male genitalia include a dispositively diagnostic set of features (Figs 2–5) and place the species in the Desmopachria convexa-signata subgroup (see above). The median lobe is short (Figs 2, 3). In lateral aspect it is irregular in shape, medially expanded ventrally and with the apical portion slender, short, slightly curved dorsad and apically narrowly rounded (Fig. 2). In ventral aspect it is very broad, basally deeply U-shaped, apically deeply bifid, each ramus broad basally, apically narrowed and slightly curved laterad (Fig. 3). The lateral lobe in ventral aspect is elongate, broad, of subequal width throughout to a broadly truncate apex, with the subapical articulable lobe small and broad (Fig. 4). The lateral lobe in lateral aspect is very broad basally with the apex slender, subapically slightly expanded on the dorsal margin and apically sharply pointed with the subapical articulable process short and slender (Fig. 5).

Measurements. TL = 1.2–1.3 mm, GW = 0.8 mm, PW = 0.7 mm, HW = 0.4–0.5 mm, EW = 0.2 mm, TL/GW = 1.9, HW/EW = 2.0. Body round, subspherical, lateral margins continuous between pronotum and elytron (Fig. 1), dorsoventrally broad.

Coloration (Fig. 1). Head and pronotum yellow. Elytron orange, with distinct but weakly margined maculae at humeral angle, anterolaterally extending to near suture, lateromedially and apically; surface not iridescent. Ventral surfaces and appendages yellow.

Sculpture and structure. Head (Fig. 1) broad, anteriorly produced in rounded margin; anterior margin of clypeus margined with conspicuous, continuous, flattened bead; surface of head shiny, very finely and sparsely punctate; eyes large (HW/EW = 1.2–1.4); antennae short, scape and pedicel relatively large and rounded, flagellomere III long and slender, apically expanded, antennomeres IV–X short and broad, lobe at anterodorsal angle, antennomere XI elongate, apically pointed. Pronotum short, lateral margins short, broadly curved with narrow, even bead; surface shiny, nearly impunctate medially, more but sparsely punctate along anterior and posterior margins, punctation variable, fine to course. Elytron moderately broad, laterally broadly curved; surface impunctate. Prosternum extremely short, longitudinally compressed, medially slightly carinate; prosternal process slender anteriorly, with distinctive, small medial tubercle, apically short and broad, concave, apically broadly pointed. Metaventrite broad and evenly smoothly convex medially, surface shiny, impunctate, anteromedially with curved transverse carina between posterior margins of mesocoxal cavities; metaventrite wings extremely slender. Metacoxa with medial portion short, about 1/3 length of metaventrite medially, metacoxal lines distinctly divergent anteriorly; lateral portion of metacoxa extremely large, anteriorly strongly expanded; surface shiny, impunctate, but slightly rugulose medially. Metatrochanter large, longer than ventral margin of metafemur anterior to metatrochanter apex; legs otherwise not noticeably modified. Abdomen with surfaces shiny and smooth, impunctate.

Male genitalia. Male median lobe in lateral aspect short, medially somewhat expanded on ventral margin, apically convergent to sharply angulate apex (Fig. 1). Median lobe in ventral aspect broad, base in broad “U” shape, apically deeply bifid, each ramus elongate, broad basally, and apically pointed (Fig. 2). Lateral lobe in ventral aspect moderately broad, apically gently curved laterad, with apex subtruncate, subapical articulable process oblique and flattened (Fig. 3). Lateral lobe in lateral aspect very broad basally, constricted medially, apically slender, slightly and broadly curved dorsad, apex pointed, subapically articulable lobe slender, directed ventrad (Fig. 4).

This species is named manco, after Manco, the younger bounty hunter in the Sergio Leone film "For a Few Dollars More".

This species is known from two localities in Guyana, Region IX (Fig. 58).

The type and paratype were collected in “detrital pools” and a “marshy area.”

Figures 1–10. 

Desmopachria species. 1–5 D. manco 1 habitus 2–5 male genitalia 2 male median lobe, right lateral aspect 3 male median lobe, ventral aspect 4 male left lateral lobe, ventral aspect 5 male left lateral lobe, left lateral aspect 6–10 D. mortimer 6 habitus 7–10 male genitalia 7 male median lobe, right lateral aspect 8 male median lobe, ventral aspect 9 male left lateral lobe, ventral aspect 10 male left lateral lobe, left lateral aspect. Scale bars: 1.0 mm (1, 6).

Costa Rica, Cartago Province, Tapanti National Park, pasture by Rio Orosi, ca. 1200 m.

Holotype in KUNHM, male labeled, “Costa Rica: Cartago Province Tapanti National Park: 24.v.2006 pasture by Rio Orosi: c. 1200 m leg. A.E.Z. Short, AS-06-043/ SEMC0895195 KUNHM-ENT/ Holotype Desmopachria mortimer Miller, 2020 [red label with black line border].” Paratypes, 41, labeled same as holotype except with different specimen barcode labels (Table 1) and each with “Paratype Desmopachria mortimer Miller, 2020 [blue label with black line border].”

This is a moderately sized, somewhat elongate species of Desmopachria (Fig. 1; TL = 1.7–1.9 mm). The dorsal coloration is characteristic with diffuse darker regions medially and extending laterally onto the surface of the elytron (Fig. 6). The shape of the male genitalia is diagnostic (Figs 7–10) and place the species in the Desmopachria convexa-convexa subgroup (see above). The median lobe is short (Figs 7, 8), and in lateral aspect it is irregularly broad basally with the apical portion slender, short and curved dorsally to a narrowly rounded apex (Fig. 7). In ventral aspect it is very broad, basally broadly U-shaped, apically deeply bifid, with each ramus slender and strongly curved medially (Fig. 8). The lateral lobe in ventral aspect is irregularly shaped, broad, with the apex narrowly truncate and with a subapical articulable lobe that extends well beyond the apex of the lateral lobe and is apically acuminate and sharply pointed (Fig. 9). The lateral lobe in lateral aspect is very broad basally with the apex slender, elongate, directed dorsad, and with the subapical articulable lobe elongate, curved and apically sharply pointed (Fig. 10).

Measurements. TL = 1.7–1.9 mm, GW = 1.1–1.2 mm, PW = 0.9–1.0 mm, HW = 0.5–0.6 mm, EW = 0.3–0.4 mm, TL/GW = 1.5–1.6, HW/EW = 1.2–1.4. Body broad but slightly elongate posteriorly, lateral margins continuous between pronotum and elytron (Fig. 6), dorsoventrally broad.

Coloration (Fig. 6). Head orange, diffusely darker orange posteriorly. Pronotum orange, with darker orange region along posterior margin. Elytron orange, with diffuse, weakly margined darker regions along anteromedial margin, along elytral suture and expanded somewhat onto disc medially; surface not iridescent. Mesoventrite, metacoxa and abdominal ventrites dark orange, other ventral surfaces and appendages lighter orange.

Sculpture and structure. Head (Fig. 6) broad, anteriorly produced in broadly rounded margin; anterior margin of clypeus margined with conspicuous, continuous narrow bead; surface of head shiny, very finely and sparsely punctate, punctation slightly denser posteriorly; eyes large (HW/EW = 2.0); antennae short, scape and pedicel relatively large and rounded, flagellomere III long and slender, apically expanded, antennomeres IV–X short and broad, lobe at anterodorsal angle, antennomere XI elongate, apically pointed. Pronotum short, lateral margins short, slightly curved with narrow bead, bead wider medially, slightly angulate medially; surface shiny, nearly impunctate medially, more but sparsely punctate along anterior and posterior margins, punctation variable, fine to course. Elytron moderately broad, laterally broadly curved; surface shiny, more coarsely and evenly punctate than pronotum, punctation shallow and indistinct, of variable sizes. Prosternum extremely short, longitudinally compressed, medially slightly carinate; prosternal process slender anteriorly, with distinctive, small medial tubercle, apically short and broad, concave, apically broadly pointed. Metaventrite broad and evenly smoothly convex medially, surface shiny, with very few indistinct punctures, anteromedially with curved transverse carina between posterior margins of mesocoxal cavities; metaventrite wings extremely slender. Metacoxa with medial portion short, less than 1/2 length of metaventrite medially, metacoxal lines distinctly divergent anteriorly; lateral portion of metacoxa extremely large, anteriorly strongly expanded; surface shiny, evenly but shallowly and indistinctly punctate, punctures evenly distributed. Metatrochanter large, longer than ventral margin of metafemur anterior to metatrochanter apex; legs otherwise not noticeably modified. Abdomen with surfaces shiny and smooth, nearly impunctate.

Male genitalia. Male median lobe in lateral aspect irregularly shaped, apical portion slender, short, slightly curved dorsad, apically narrowly rounded (Fig. 7). Median lobe in ventral aspect very broad, basally U-shaped, apically deeply and broadly bifid, each ramus slender, apically narrowly rounded, gently curved, and convergent medially at apices (Fig. 8). Lateral lobe in ventral aspect irregularly shaped, broad, with subapical articulable lobe slender, undulate, apically sharply pointed and elongate, extending well beyond apex of lateral lobe (Fig. 9). Lateral lobe in lateral aspect broad basally, apex slender, oblique, directed dorsad, subapical articulable process slender, elongate curved and sharply pointed (Fig. 10).

This species is named mortimer, after Colonel Douglas Mortimer, the older bounty hunter in the film "For a Few Dollars More".

This species is known only from one locality in Costa Rica, Prov. Cartago (Fig. 58).

The only known habitat information is the type series collected in a “pasture.”