Desmopachria truncata, 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 truncata sp. nov.

Figures 63-65 , 81

Type locality.

Suriname, Sipaliwini District, Camp 4, Kasikasima, stream on trail to METS camp, 200m, 2.97731°N 55.38500°W.

Diagnosis.

This species is characterized by the male median lobe slender, apically distinctly expanded with the apex broadly truncate and the lateral lobe longer than the median lobe (Figs 64 , 65 ). The dorsal punctation on the head, pronotum and elytra is very fine and sparse. The elytra are iridescent. The genitalia are somewhat similar to Desmopachria mutata Sharp, but that species has the median lobe very slender, not as broadly expanded apically, and apically rounded, not truncate ( Young 1995: fig. 2). That species also occurs in Mexico, not northern South America ( Young 1995). Desmopachria truncata is otherwise not similar to other species in the Desmopachria portmanni-aldessa subgroup.

Description.

Measurements. TL = 2.0-2.1 mm, GW = 1.3-1.4 mm, PW = 1.0-1.1 mm, HW = 0.6-0.7 mm, EW = 0.3-0.4 mm, TL/GW = 1.4-1.5, HW/EW =1.8-2.2. Body very broad, laterally rounded, lateral margins continuous between pronotum and elytron; dorsoventrally compressed.

Coloration. Head and pronotum evenly dark orange, head slightly iridescent dorsally. Elytron evenly dark orange, iridescent, especially apically. Ventral surface of head, prosternum, head appendages, and pro- and mesolegs yellow, other ventral surfaces and metalegs darker orange, lateral portion of metacoxa and abdominal ventrites somewhat iridescent.

Sculpture and structure. Head broad, short; anterior margin of clypeus finely margined with continuous flattened narrow bead; surface of head shiny, punctation extremely fine, sparse but evenly distributed; eyes moderately large (HW/EW = 1.8-22); 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, broadly curved with continuous narrow bead; surface shiny, punctation very fine, irregular, sparse; posterior margin sinuate. Elytron broad, laterally broadly curved; surface shiny, punctate, punctures dual, fine and large interspersed, without linear series. Prosternum extremely short, longitudinally compressed, medially slightly 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; metaventrite wings extremely slender. Metacoxa with medial portion short, <1/3 length of metaventrite medially, metacoxal lines sinuate, divergent anteriorly; lateral portion of metacoxa extremely large, anteriorly strongly expanded; surface shiny, impunctate. Metatrochanter very large, subequal to length of ventral margin of metafemur; legs otherwise not noticeably modified. Abdomen with surfaces shiny and smooth, very finely and sparsely punctate.

Male genitalia. Male median lobe in lateral aspect elongate, evenly curved, apically narrowly rounded (Fig. 63 ; in ventral aspect elongate, evenly constricted medially, expanded apically to abruptly broadly truncate apex (Fig. 64 ). Lateral lobe extending distinctly beyond apex of median lobe, moderately broad, apically rounded with dense margin of long setae apically and along apicodorsal margin (Fig. 65 ).

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. The single specimen from "Upper Palumeu" has the male median lobe slightly longer and more slender with the lateral lobes apically a little more rounded. This does not seem to represent a significant difference however, and the specimen is from the same general area as the holotype. The series from Guyana similarly has some shape variation in the lateral and median lobes, but again, it does not seem to suggest species-level differences. However, additional specimens could help clarify the limits in these populations. A couple specimens are paler tan in color, but this could be because they are teneral.

Etymology.

This species is named Desmopachria truncata , Latin for the characteristic apically truncate male median lobe in this species.

Distribution.

This species is known from Sipaliwini District, Suriname and Region VIII, Guyana (Fig. 81 ).

Type material.

Holotype in NZCS, male labeled, "SURINAME: Sipaliwini District 2.97731°N, 55.38500°W 200 m Camp 4 (low, Kasikasima; sandy stream on trail to METS camp 20.iii.2012; SR12-0320-02A leg. A. Short; 2012 CI-RAP Survey/ SEMC1087011 KUNHM-ENT [barcode label]/ HOLOTYPE Desmopachria truncata Miller, 2021 [red label with black line border]." Paratypes, 17; 14 in NZCS and SEMC labeled same as holotype except each with different barcode labels (Table 1 ); 1 in SEMC labeled, "SURINAME: Sipaliwini District N 2.47700', W 55.62941', 275 m Camp 1, Upper Palumeu leg. A. Short; Flight Intercept Trap 10-16.iii.2012; SR12-0310-TN1 2012 CI-RAP Survey/ SEMC1089093 KUNHM-ENT; 2 in CBDG and SEMC labeled, "GUYANA: Region XIII [sic] 5°10.514'N, 59°28.970'W, 440 m Kaiteur Nat’l Park, trail by guest house; small forest stream leg. A. Short; 15.iii.2014 GY14-0315-03A/ SEMC1328988 KUNHM-ENT [barcode label]" and “… SEMC1328993 KUNHM-ENT]." All paratypes also with “… PARATYPE Desmopachria truncata Miller, 2021 [blue label with black line border]."

Desmopachria portmanni-aldessa subgroup - iridescent Desmopachria with a forked male prosternal process (= Desmopachria (Pachiridis) Young, 1980)

Desmopachria aldessa Young, 1980 - Brazil (Braga and Ferreira-Jr. 2014), Trinidad

Desmopachria anastomosa sp. nov. - Guyana

Desmopachria angulata sp. nov. - Guyana, Suriname

Desmopachria aurea Young, 1980 - Brazil (Braga and Ferreira-Jr. 2014), Suriname

Desmopachria emarginata sp. nov. - Suriname

Desmopachria imparis sp. nov. - Guyana

Desmopachria impunctata sp. nov. - Suriname

Desmopachria iridis Young, 1980 - Brazil

Desmopachria novacula Young, 1980 - Suriname

Desmopachria truncata sp. nov. - Guyana, Suriname.

Figures

Figure 81. Desmopachria species distributions, Desmopachria portmanni-aldessa species group, Desmopachria portmanni-portmanni species group, and Desmopachria striola species group.

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.