Desmopachria varians Wehncke 1877

Braga, Rafael Benzi, 2018, Six new species and new records of the genus Desmopachria Babington (Coleoptera: Dytiscidae: Hyphidrini) from Brazil and redescription of D. varians Wehncke, 1877, Papéis Avulsos de Zoologia 58, pp. 1-15 : 11-14

Desmopachria varians Wehncke 1877 ( Figures 7 A-L)

Diagnosis: This species is characterised by its size, large among Desmopachria species (2.2-2.7 mm), for the characteristic elytral macula pattern ( Fig. 7C ), for the presence of a transversal and waved suture in last segment ( Fig. 7D ) and for the peculiar male genitalia (Figs. G-N).

Description: Total length 2.2-2.7 mm; maximum width of body 1.6-1.7 mm; elytral length 1.5-1.9 mm; maximum width of the pronotum 1.2-1.3 mm.

Colouration ( Figs. 7 A-C): Head yellow, pronotum yellow with brown macula at base ( Figs. 7A and C ); each elytron yellow with elytral suture dark and two brown longitudinal fasciae parallel to elytral suture, the inner fascia fused with suture in middle and the apical tip of outer fascia touch the inner in the apical quarter ( Fig. 7C ). Ventral surface testaceous with exception of light brown metasternum and metacoxa ( Fig. 7B ).

Structure and sculpture: Body globular with head inconspicuously punctate; Pronotum and each elytron with coarse deep and very dense distributed punctures. Clypeus beaded; antennae with rounded scape, pedicel narrower and longer than others flagellomeres, antennomeres 5-9 slightly expanded in apical half. Pronotum short and wide, with a lateral bead and without basal striae; pro- and mesotarsus with ventral adhesive setae; prosternal process broad, apically rounded, shallowly concave. Elytral suture margined. Ventral surface very fine, with shallow and scarcely distributed punctures. Ventral surface of metatibia covered with short and wide spine. Apical ventrite with conspicuous waved sutures ( Fig. 7D ).

Male genitalia( Figs.7 E-L): Median lobe of aedeagus very short, half the length of lateral lobes ( Figs. 7 E-F and H); in dorsal view basal half parallel-sided and apical half triangular, narrowed toward apex ( Fig. 7J ); in lateral view basal half broader and apical half bended to ventral side and narrowing to pointed apex ( Fig. 7K ). Lateral lobes in dorsal view almost parallel with inner margin straight until apex and outer margin rounded to apex in apical forth, giving an overall semicircular looking to the apex ( Fig. 7I ); in lateral view basal half broad almost oval and apical half very thin and discretely sinuate ( Fig. 7L ).

Examined material: BRAZIL. Alagoas State: Delmiro GouveiaMunicipality, Lagoinha [09°26’24”S, 38°01’48”W], 20-25.iii.1992, Sachsse R. (60 exs. DZRJ 656 ) ; Olho d’água do Casado Municipality, Fazenda Sr. Luis do Chalé , Chesf Ingerio EIA Xingó , [09°30’00”S, 37°49’48”W], 18.iii.1992, Sachsse R. (6 exs. DZRJ 645 ). Amazonas State, Novo Airão Municipality, Anavilhanas Archipelago, Lago do Prato 03.v.1981 Jorge Luiz Nessimian. (1 ex. DZRJ 2688 ). Bahia State: Caetité Municipality, Distrito Uranifero Lagoa Real, INB, [14°03’36”S, 42°29’24”W], 08-16.i.2000, Nessimian [20°44’44”S, 60°44’42”W], J.L. & Baptista D.F. Horto (2 exs. DZRJ 2676 ), Bacia de DecantaÇão (6 exs. DZRJ 2672 ) ; Encruzilhada Municipality, 07.xi.1972, M Alvarenga BLT, det. FN Young. (1 ex. USNM). Minas Gerais State, Manga Municipality, Mocambinho , Agroceres , [14°45’21”S, 43°55’55”W], 22-25.x.1992, Carvalho A.L. (4 exs. DZRJ 2674 ). Rio de Janeiro State, Cabo Frio Municipality, Ilha do Cabo Frio , Lago, [22°52’46”S, 42°01’07”W], 14-27.i.1984, Sampaio, Carvalho & Kosawa (7 exs. DZRJ 333 ) .

Taxonomic notes: First included by Young (1980) in the subgenus Pachriostrix Guignot, 1950 , this species was then moved to the subgenus Pachriodesma Guignot, 1949 by Young (1990b) and finally considered impossible to be inserted in a known species groups by Miller (2001) and yet remain ungrouped. The sutural striae on elytra indicate D. varians should be placed in the D. striola group, however, this stria was also found in species belonging to other groups, such as D. anuine , D. carranca and D. nigrisphera , demonstrating that sutural striae is a relatively weak character for inferring relationship, problem already highlighted by Miller (2001).

The bright elytral colour pattern of this species with longitudinal brown maculae is typical of the D. dispersa group, but D. varians does not have the characteristic basal striae on the pronotum of D. dispersa group. The shape of male genitalia, with triangular median lobe very small in comparison with lateral lobes which are flat, almost parallel in dorsal view, is only comparable to D. chei Miller, 1999 and D. rex Gustafson & Miller, 2012 , but both species lack elytral macula and D. rex is much larger than D. varians .

Geographic distribution: This species was only known from Bahia and Ceará states in Brazil. Its distribution is here expanded to the Brazilian states of Alagoas, Amazonas, Minas Gerais and Rio de Janeiro.

Figures

Figures 7A-L. Desmopachria varians. (A) Dorsal View. (B) Ventral view. (C) Colour pattern of Elytron. (D) Apical ventrite. (E-M) Male genitalia. (E) Dorsal view. (F) Ventral view. (G) Lateral view. (H) Coverslip dorsal view. (I) Lateral lobe dorsal view. (J) Median lobe dorsal view. (K) Median lobe lateral view. (L) Lateral lobe lateral view.Figs.1A-D scale bars= 1 mm,Figs.1E-L scale bars= 0.1 mm.