Desmopachria imparis, Miller, 2022

Miller, Kelly B., 2022, Nineteen new species of Desmopachria Babington, 1841 (Coleoptera, Adephaga, Dytiscidae, Hydroporinae, Hyphydrini) with notes on the taxonomy of the genus, ZooKeys 1136, pp. 1-56 : 1

Desmopachria imparis sp. nov.

Figures 57-59 , 79

Type locality.

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

Diagnosis.

This species is unique because of the asymmetrical shape of the male median lobe. In ventral aspect the median lobe is distinctly asymmetrical, though not strongly so (Fig. 58 ). However, this is the only known species of the Desmopachria portmanni group with an asymmetrical male median lobe. Punctation on the elytron is dual with some small punctures interspersed among numerous larger punctures. The elytral surface is otherwise shiny with some opalescent iridescence evident. Externally, among northern South American species this one is similar to Desmopachria lineata sp. nov., but that species has distinctive linear series of punctures on the elytra and a differently shaped male median lobe (Figs 3 , 4 ).

Description.

Measurements. TL = 2.1-2.2 mm, GW = 1.5-1.6 mm, PW = 1.1-1.2 mm, HW = 0.7-0.8 mm, EW = 0.4 mm, TL/GW = 1.4, HW/EW = 1.8-1.9. Body broadly oval, laterally broadly curved, lateral margins approximately continuous between pronotum and elytron.

Coloration. Head and pronotum evenly yellow. Elytron evenly brownish orange, iridescent, especially apically. Ventral surface of head, prosternum, head appendages, and pro- and mesolegs yellow, other ventral surfaces and metalegs darker orange.

Sculpture and structure. Head broad, short; anterior margin of clypeus broadly curved, flattened, margined with conspicuous, continuous flattened narrow bead; surface of head shiny, extremely finely and sparsely punctate; eyes large (HW/EW = 1.8-1.9); antennae short, scape and pedicel relatively large and rounded, flagellomere III long and slender, apically expanded, antennomeres IV-X short and broad, antennomere XI elongate, apically pointed. Pronotum short, lateral margins short, slightly curved with continuous narrow bead; surface shiny, extremely finely and sparsely punctate, posterior margin sinuate. Elytron broad, laterally broadly curved and rounded; surface shiny, punctate, punctures dual, mostly larger, interspersed with smaller ones. Prosternum extremely short, longitudinally compressed, medially carinate; prosternal process in male very slender anteriorly, with low, indistinct medial tubercle, bifid apically with deep medial pit, in female slender anteriorly, with distinctive, small medial tubercle, apically short and broad, medially slightly carinate, apically acutely pointed. Metaventrite broad and evenly smoothly convex medially, surface shiny, impunctate medially, shallowly and minutely punctate laterally and posteromedially; metaventrite wings extremely slender. Metacoxa with medial portion short, <1/3 length of metaventrite medially, metacoxal lines slightly sinuate, divergent anteriorly; lateral portion of metacoxa extremely large, anteriorly strongly expanded; surface irrorate, somewhat opalescent. Metatrochanter very large, subequal to length of ventral margin of metafemur; legs otherwise not noticeably modified. Abdomen with surfaces shiny and smooth, somewhat opalescent, very finely and sparsely punctate.

Male genitalia. Male median lobe slightly but distinctly asymmetrical; in lateral aspect long, evenly broad, evenly and broadly curved on both dorsal and ventral margins, apex narrowly rounded (Fig. 57 ); in ventral aspect asymmetry evident, moderately broad basally, apically narrowed to narrowly rounded apex, lateral margins irregularly sublinear on each side, but different in shape on each side, medial groove directed primarily to right of central line (Fig. 58 ). Lateral lobe broad basally, abruptly narrowed and slender for most of apical length, apex slightly broadened and broadly rounded, with dense long series of setae along dorsal margin medially and with field of short setae mediolaterally, apex with series of short setae (Fig. 59 ).

Sexual dimorphism. Male pro- and mesotarsomeres I-III slightly more broadly expanded and with ventral adhesive setae. Male and female prosternal processes different as in all Desmopachria portmanni group species.

Variation. No significant variation was discovered among the few specimens examined.

Etymology.

This species is named Desmopachria imparis , Latin for uneven, referring to the asymmetrical male median lobe.

Distribution.

This species is known from one locality in Region IX, Guyana (Fig. 79 ).

Type material.

Holotype in CSBD, male labeled, "GUYANA: Region IX 2°05.095'N, 59°14.174'W, 250m Parabara, Trail to mines detrital pools in forest leg. Short, Isaacs, Salisbury 2.xi.2013; GY13-1102-01A/ SEMC1271236 KUNHM-ENT [barcode label]/ HOLOTYPE Desmopachria imparis Miller, 2021 [red label with black line border]." Paratypes, 3 in SEMC (1 male, 2 females) labeled same as holotype except with different specimen barcode labels [SEMC1271235, SEMC1271237, SEMC1271238] and each with “… PARATYPE Desmopachria imparis Miller, 2021 [blue label with black line border]."

Figures

Figures 51 - 71. Desmopachria species. (51 - 53) Desmopachria angulata 51 median lobe, right lateral aspect 52 median lobe, ventral aspect 53 right lateral lobe, right lateral aspect (54 - 56) Desmopachria emarginata 54 median lobe, right lateral aspect 55 median lobe, ventral aspect 56 right lateral lobe, right lateral aspect (57 - 59) Desmopachria imparis 57 median lobe, right lateral aspect 58 median lobe, ventral aspect 59 right lateral lobe, right lateral aspect (60 - 62) Desmopachria impunctata 60 median lobe, right lateral aspect 61 median lobe, ventral aspect 62 right lateral lobe, right lateral aspect (63 - 65) Desmopachria truncata 63 median lobe, right lateral aspect 64 median lobe, ventral aspect 65 right lateral lobe, right lateral aspect (66 - 68) Desmopachria bisulcata 66 median lobe, right lateral aspect 67 median lobe, ventral aspect 68 right lateral lobe, right lateral aspect (69 - 71) Desmopachria irregulara 69 median lobe, right lateral aspect 70 median lobe, ventral aspect 71 right lateral lobe, right lateral aspect.

Figures 79, 80. Desmopachria species distributions. 79 Desmopachria nitida species group and Desmopachria portmanni-aldessa species group 80 Desmopachria portmanni-aldessa species group.

Figures 1 - 12. Desmopachria species. (1, 2) Desmopachria divergens 1 habitus 2 male genitalia, ventral aspect. (3,4) Desmopachria lineata 1 habitus 2 male genitalia ventral aspect (5 - 8) Desmopachria surinamensis 5 habitus 6 - 8 male genitalia 6 median lobe, right lateral aspect 7 median lobe, ventral aspect 8 right lateral lobe, right lateral aspect (9 - 12) Desmopachria tenua 9 habitus 10 median lobe, right lateral aspect 11 median lobe and right lateral lobe, ventral aspect; 12 right lateral lobe, right lateral aspect. Scale bars: 1.0 mm for habitus drawings.