Diplocheila (Diplocheila) walterrossii, Allegro & Giachino, 2021

Allegro, Gianni & Giachino, Pier Mauro, 2021, The genus Diplocheila Brulle, 1834 in Cambodia, with descriptions of two new species (Coleoptera, Carabidae, Licinini), ZooKeys 1044, pp. 427-448 : 427

Diplocheila (Diplocheila) walterrossii sp. nov. Figures 4 , 10 , 16 , 19 , 22 , 29 , 33

Type locality.

Cambodia, Siem Reap Province, N Siem Reap City, 13°26'29"N, 103°52'25"E.

Material examined.

Holotype: ♂, Cambodia, Siem Reap Province, N Siem Reap City , 13°26'29"N, 103°52'25"E, light trap, 13.XI.2018, W. Rossi and V. Kong leg. (CGi).

Paratypes: (7 ♂♂ and 3 ♀♀); 2 ♂♂, same data as HT ; 2 ♂♂ Cambodia, Kampong Chhnang Province, Khom Domnatpopol, Tonle Sap Lake , 12°14'14"N, 104°41'15"E, light trap, 21.V.2018, Rossi, Bernardi and Kong leg. ; 1 ♂ 1 ♀, Cambodia, Kampong Chhnang, banks of Tonle Sap Lake , light trap, 17.V.2019, W. Rossi and V. Kong leg. ; 1 ♂, Cambodia, Kampong Chhnang, Rolea B’ier District, Toulkrolanh Village , 12°13'31"N, 104°39'50"E, light trap, 7.XI.2018, W. Rossi and V. Kong leg. ; 2 ♀♀, Cambodia, Banteay Meanchey Province, near Sisophon, Campus of the Mean Chey University , light trap, 22.X-23.XI.2019, P. Bun and W. Rossi leg. ; 1 ♂, Cambodia, Khsam , Kampong Chhnang, 12°16'47"N, 104°39'28.6"E, light trap, 29.XI-3.XII.2019, W. Rossi and V. Kong leg. (CAl, CCa, CGi, BMNH, MCSNG).

Diagnosis.

A medium-sized (ABL: 15-18 mm) Diplocheila of the Diplocheila polita group in the subgenus Diplocheila Diplocheila (sensu Ball 1959). Among the species of this group having a sexsetose labrum, it is easily distinguished from D. erwini sp. nov. by the larger body size (15-18 mm vs 12-14 mm), from D. laevigata and D. laevigotoides by the more transverse pronotum (PW/PL = 1.38 vs 1.28-1.32), from D. indus by the hind angles of pronotum not protruding (externally protruding in D. indus ) and from all these species by the morphology of the aedeagus.

Description.

Habitus: ABL: 15-18 mm (HT ♂ 15.6 mm). Body parallel-sided, moderately shiny, black with antennae and palpi piceous-brown (Fig. 4 ).

Head: almost quadrangular, robust, glabrous except for the supraorbital setae. Eyes markedly convex; a single supraorbital seta on each side. Dorsum with microsculpture not evident, only with scattered punctures visible at>100 × magnification; frontal impressions short and superficial. Labrum symmetrically and deeply (LR = 0.72) emarginate, with six setigerous punctures on anterior margin (4 medial equidistant + 2 lateral on lobes). Clypeus trapezoid, distinctly concave anteriorly, with 1 seta at each anterolateral corner. Antennae moderately long, densely pubescent from segment 4, with terminal two articles surpassing base of pronotum; segments elongate, the second one short, as long as a half of first. Mandibles elongate, broad, approximately similar to one another (the left with apical cutting edge more concave), with scrobe well-defined and glabrous and apex blunt; terebral tooth triangular and prominent. Labial and maxillary palps fusiform, with apices narrowly truncate.

Thorax: pronotum smooth, with very faint isodiametric microsculpture evident at>200 × magnification and with scattered punctures, transverse (PW/PL = 1.38), widest just above middle (Fig. 10 ). Disk moderately convex. Sides moderately rounded in anterior half, delicately sinuate backwards. Hind angles rounded obtuse, with a postero-lateral seta. Posterior margin rectilinear between basal impressions, which are linear and markedly impressed; anterior margin with front angles nearly obsolete. A single lateral seta on each side at anterior third. Lateral bead continuous, separated from the discal area by a narrow groove, only scarcely dilated before hind angles. Medial longitudinal impression fine, nearly reaching anterior and posterior margins; anterior transversal impression absent.

Elytra: moderately long (EL/EW = 1.65), parallel-sided, slightly convex and flattened on disk, widest at middle, with rounded shoulders and sides delicately sinuate before apex. Surface moderately shiny; microsculpture evident only at high magnification (>100 ×), consisting of fine, slightly transverse meshes. Epipleura without any distinct external plicae ("uncrossed epipleura"). Intervals moderately convex, smooth; striae deeply impressed on the whole length, delicately punctate. Parascutellar stria present; scutellar setigerous pore present at base of stria 1, just before conjunction with stria 2. Basal margin complete. Discal setigerous punctures absent; umbilicate series of setigerous punctures continuous, but punctures more widely spaced at middle. Hind wings fully developed.

Ventral surface (thorax and abdomen): prosternum and proepisterna glabrous and impunctate (only with very fine punctures). Metepisterna twice as long as their width at anterior side; metepimera narrow, nearly rectangular. Prosternal intercoxal process parallel-sided with blunt apex, delicately bordered. Abdominal ventrites IV-VI shiny but shagreened at sides, glabrous except one pair of subapical central setae; males with 2, females with 4 setae at apex of ventrite VII.

Legs: moderately slender. Posterior face of femora with 1 seta in profemora, 2 setae in mesofemora and metafemora. Metatrochanters glabrous and as long as one-third of metafemora. Protibial antennal cleaning organ well developed, with 2 clip setae. Protibiae robust, with 6 or 7 outer apical spines; mesotibiae with a group of setae at middle of inner face; metatibiae longitudinally furrowed at inner face. Dorsal face of tarsomeres smooth. Protarsomeres 1-3 of males moderately dilated, slightly asymmetrical; meso- and metatarsomeres not dilated in both sexes; tarsomere 5 ventrally glabrous, dorsally with 2 apical setae; claws smooth.

Male genitalia: median lobe of aedeagus short and moderately swollen before apex in lateral view (Fig. 22 ); apical lamella very short and apically rounded in dorsal view (Fig. 29 ), apex thick and very slightly bent downwards in lateral view. Ostium long, in dorsal position. Right paramere elongate and subtruncate at apex; left paramere conchoid.

Etymology.

This species is named after its collector, Walter Rossi, a world-renowned specialist in entomoparasitic fungi, as a token of our esteem and as a sign of gratitude for the gift to the authors of the specimens of the new species.

Distribution and ecology.

Geographical distribution : this species is recorded from Central and North-Western Cambodia (Fig. 33 ). Life habits: the specimens of the type series were collected by light trapping. No other data are available.

Remarks.

Diplocheila walterrossii sp. nov. belongs to the D. polita group (sensu Ball 1959), as it shares the characters distinguishing this group and, at first sight, is very similar in external morphology to D. laevigata . Nevertheless, at a deeper examination its aedeagus (Figs 22 , 29 ) reveals evident morphological differences and is easy distinguished from that of D. laevigata (Figs 20 , 26 , 27 ), as well as from that of D. erwini sp. nov. (Figs 23 , 30 ), both species sympatric and syntopic with D. walterrossii sp. nov. in Cambodia. Moreover, the new species shows a character almost unique in this group, as far as we know, that is the less enlarged male fore tarsi 1-3. For these reasons, D. walterrossii sp. nov. could represent a rather isolated species in the D. polita group, and its closest relatives remain uncertain.

Figures

Figure 4. Diplocheila walterrossii sp. nov.: habitus of holotype.

Figure 33. Distribution map of Diplocheila walterrossii sp. nov. and D. erwini sp. nov. in Cambodia.

Figures 6 - 11. Pronotum of Diplocheila species 6 D. laevigata HT 7 D. laevigotoides HT 8 D. laevigata from Cambodia 9 Diplocheila sp. from Thailand 10 D. walterrossii sp. nov. HT 11 D. erwini sp. nov. HT.

Figures 12 - 17. Labrum of Diplocheila species 12 D. laevigata HT 13 D. laevigotoides HT 14 D. laevigata from Cambodia 15 Diplocheila sp. from Thailand 16 D. walterrossii sp. nov. HT 17 D. erwini sp. nov. HT.

Figures 18 - 19. Male protarsi of Diplocheila species 18 D. laevigata from Cambodia 19 D. walterrossii sp. nov. HT.

Figures 20 - 25. Aedeagus in lateral view of Diplocheila species 20 D. laevigata from Cambodia 21 Diplocheila sp. from Thailand 22 D. walterrossii sp. nov. HT 23 D. erwini sp. nov. HT 24 D. laevis from Cambodia 25 D. latifrons from Cambodia.

Figures 26 - 32. Aedeagus in dorsal view of Diplocheila species 26 D. laevigata HT 27 D. laevigata from Cambodia 28 Diplocheila sp. from Thailand 29 D. walterrossii sp. nov. HT 30 D. erwini sp. nov. HT 31 D. laevis from Cambodia 32 D. latifrons from Cambodia.