Desmopachria nigricoxa, Braga, 2018

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 : 9

Desmopachria nigricoxa sp. nov.

( Figures 5 A-K)

Diagnosis: Large size for the genus 2.3-2.4 mm. Male median smaller than the lateral lobe with wide apex ( Figs. 5 D-F); Lateral lobes in dorsal almost S-shaped ( Fig. 5H ).

Description: Holotype male: total length 2.4 mm; maximum width of body 1.8 mm; elytral length 1.6 mm; maximum width of the pronotum 1.4 mm.

Colouration ( Figs. 5 A-C): Head light brown; pronotum light brown with base dark brown ( Fig. 5A ); each elytron dark brown with elytral suture area darker and a lateral light brown ( Fig. 5B ); venter light brown with exception of dark brown metacoxae ( Fig. 5C ).

Structure and sculpture: Body rounded with dense punctuation; punctures fine and deep in dorsal surface; elytral surface with a line of very fine and deep punctuations, in ventral surfaces sparsely distributed punctuations large and shallow. Clypeus truncated; antennae with rounded scape, pedicel narrower and longer than others antennomeres, antennomeres 5-9 slightly expanded in apical half. Pronotum short and wide, without basal striae and lateral bead; prosternal process apically strongly forked, area between rami forming a deep pit. Elytral suture without margin with a parallel line of very coarse and deep punctures. Ventral surface of metatibia covered with short and wide spines. Apical ventrite smooth without sutures or marks.

Male genitalia ( Figs. 5 D-K): Median lobe of aedeagus three quarter longer than lateral lobes ( Figs. 5 D-G); in dorsal view gently narrowing, apex arched ( Fig. 5I ); in lateral view basal third broad, apical and middle third narrowing and bended to dorsal view, apex rounded ( Fig. 5J ). Lateral lobes in dorsal view almost S-shape with a dense row of setae on inner margin of apical half ( Fig. 5H ); in lateral view basal third expanding towards, middle and apical third rectangular ( Fig. 5L ).

Intraspecific variation: Small variations in length and width: Total length 2.3-2.5 mm; maximum width 1.6-1.7 mm.

Type material: Holotype male: “ Brasil, Mato Grasso , Chapada dos/ Guimarães , Parque Nacional da/ Chapada dos Guimarães,/ Cachoeira Marimbondo,/ 15°25’60”S, 55°43’12”W,/ 01.iii.2016, Ferreira-Jr N. &/ Guimaraes B., MTNB01 638 m [paper white label]”,“5964 [plastic blue label]” “ HTYPE [plastic red label]” ( DZRJ) . Paratypes:“ Brasil, Mato Grasso, Chapada dos/ Guimarães, Parque Nacional da/ Chapada dos Guimarães,/ Cachoeira Marimbondo,/ 15°25’60”S, 55°43’12”W,/ 01.iii.2016, Ferreira-Jr N. &/ Guimaraes B., MTNB 01 638 m [paper white label]”, “5962 [plastic blue label]”, “ PTYPE [plastic red label]” (4 exs.) ( DZRJ).

Taxonomic notes: This new species belongs to the D. portmanni group sensu Miller (2001) having the prosternal process sexually dimorphic. The combination of the male median lobe having a wide apex and being smaller than the lateral lobe, as well as the large body size is distinctive for this species. Desmopachria minuta Sharp 1882 and D. amyae Miller 2001 both have a male median lobe with a wide apex but their medium lobe lenght are almost the same to those of the lateral lobe and their body sizes are smaller than D. nigricoxa sp. nov. The species D. aurea Young 1980 , D.variegata Sharp 1882 and D. specula Sharp 1887 have the male median lobe much smaller than the lateral lobe but do not have the wide apex and are also have body size smaller than this new species. Desmopachria bryanstoni Clark 1862 and D. zetha Young 1995 are similar in the length of the body and male median lobe but the apex of the male median lobe is narrower.

Etymology: The specific name is formed by a combination of the Latin adjective “nigra” meaning dark and the noun “coxa” meaning thigh, referring to the metacoxae colour.

Geographic distribution: Known only from the Mato Grosso State of Brazil.

Figures

Figures 5A-K. Desmopachria nigricoxa. (A) Dorsal View. (B) Colour pattern of Elytron. (C) Ventral view. (D-K) Male genitalia. (D) Dorsal view. (E) Ventral view. (F) Lateral view. (G) Coverslip dorsal view. (H) Lateral lobe dorsal view. (I) Median lobe dorsal view. (J) Median lobe lateral view. (K) Lateral lobe lateral view. Figs.5A-C scale bars = 1 mm, Figs.5D-K scale bars = 0.1 mm.