Diochus basseti, Huang & Zhou & Janák & Zhou, 2024

Huang, Tian, Zhou, Yu-Lingzi, Janák, Jiří & Zhou, Hong-Zhang, 2024, Four new species and a key to Australian species of the genus Diochus Erichson (Coleoptera: Staphylinidae, Staphylininae, Diochini), Zootaxa 5512 (3), pp. 343-372 : 346-348

1. Diochus basseti sp. nov.

( Figs 2-1; 2-2 )

Type locality. Australia: Queensland: Laidley , dry river .

Type material. Holotype: male, Australia: Queensland: Laidley , dry river, 16. III. 1983, litter, Y. Basset collected ( MHNG) . Paratypes: Australia: Queensland: 1 male, with same data as holotype ( MHNG) ; 1 female, Highdale nr Samford, 30. VIII. 1987, open for. Eucalyptus, Y. Basset collected ( MHNG) .

Measurements. BL = 5.82 mm, FL = 2.51 mm, HL = 0.70 mm, HW = 0.53 mm, EL = 0.16 mm, TL = 0.42 mm, ANL = 1.41 mm, ANT1 = 0.22 mm, ANT2 = 0.14 mm, ANT3 = 0.16 mm, ANT4 = 0.12 mm, ANT 11 = 0.15 mm, PL = 0.89 mm, PW = 0.72 mm, EL = 0.87 mm, EW = 1.04 mm, SL = 0.67 mm.

Description. Body ( Fig 2-1A ) long, narrowed anteriorly and posteriorly, large-sized. Body yellow to dark brown, pronotum yellow, abdominal intersegmental membrane lighter. Legs yellowish brown, tarsi distinctly lighter. Antennae yellowish brown, apex of each antennomere lighter. Maxillary and labial palpi brown.

Head ( Fig 2-1A ). Oblong in shape, 1.35 times as long as wide. Tempora straight and parallel, posterior angles rounded. Dorsal surface shiny, bearing distinct transverse microstriae, also with coarse and sparse punctures. Head with 5−7 irregular punctures scattered around each eye and numerous smaller punctures on deflexed portion of tempus and near posterior margin. Each side of cranium with characteristic punctures: one frontal puncture on frontal region, two anterolateral punctures near antennal insertion, three lateral punctures near dorsal margin of eye, with temporal puncture and occipital puncture near basal margin; disc surface bearing two additional paired punctures in middle area. Frontal furrows and anteocular furrows absent. Eye large-sized, distinctly protruding laterad, longitudinal diameter about half of length of tempora (eye: tempora = 0.39). Epistoma not flattened, abruptly oblique, anterior margin slightly emarginate medially. Distance between antennal insertions (0.16 mm) distinctly longer than distance from antenna to eye (0.08 mm). Ventral surface with scattered punctures, interspaces between them about 4 puncture diameters. Gular sutures deep, confluent at basal 1/4, then extended to base.

Antennae ( Fig 2-1B ). Scape rod-shaped, slightly thickened apically, shorter than two subsequent antennomeres combined; antennomere 2 slightly elongate,; antennomere 3 distinctly longer than 2; antennomere 4 about 1.5 times of the width, antennomeres 4 to 10 gradually shortened, antennomere 4 longer than 10; antennomere 11 distinctly longer than 10.

Mouthparts. Labrum nearly hexagonal, lateral margin straight, widest at basal 1/3 to 1/2; width of anterior margin about half width at widest point. Mandibles ( Figs 2-1D ) falciform, left one with three small teeth on inner margin, whereas right one with two.

Neck. Cylindrical, shiny, only bearing shallow microsculpture, width 0.17 mm, shorter than 1/3 of head width. Dorsal surface with distinct groove; ventral surface with gular sutures forming triangular region, with deep transverse median furrow.

Prothorax ( Fig 2-1A ). Pronotum elongate (PL to PW ratio 1.23), distinctly longer and wider than head.Anterior region near anterior angles deflexed, lateral margins widened posteriad to basal 1/4 (widest at 1/4), then convergent backwards, anterior and posterior angles broadly rounded. Dorsal surface glossy, extensively with micropunctures, but without any microsculpture. Each side of longitudinal midline with one row of punctures composing of 3 large punctures and 2 additional punctures outside of puncture row, 13–15 punctures scatted near each margin (including anterior, lateral and posterior margins). Prosternum bearing transverse ridge between basisternum and furcasternum, angularly backwards.

Pterothorax ( Fig 2-1A ). Mesoscutellum triangular and small, surface shiny, bearing distinct microstriae, but without any punctures. Transverse ridge on mesoventrite wave shaped; paired oblique furrows short but deep; carina limiting mesocoxal cavity slightly arcuate. Discrimen region on metaventrite normally elevated.

Elytra ( Fig 2-1A ). Elytra yellow, transverse and short (EL to EW ratio 0.78), distinctly longer and wider than pronotum. Humeri well developed, lateral margins divergent posteriorly, posterior margin not rounded, but obliquely truncate. Dorsal surface shiny, flattened, without microsculpture; each elytron with row of 5 punctures along suture, row of 5 punctures on disc, also with 4−5 rows of punctures on deflexed portion.

Legs ( Fig 2-1C ). First four segments of protarsi heart-shaped, moderately dilated, and those of meso- and metatarsi slender. Last segment of protarsi slightly shorter than 2−4 together, that of meso-, meta- shorter than length of each 2−3.

Abdomen ( Fig 2-1A ). Broadest at segment V. Tergites III–VII covered with dense and transverse microstriae; each tergite with dense yellow pubescence, also with row of darker and coarser setae at posterior margin of tergites III–VI. Tergites III–VII with basal impression near anterior margin, respectively, each one only possessing one basal transverse carina; all abdominal tergites with surface shiny, bearing polygonal reticulum, with dense punctures. Posterior margin of tergite VII with distinct palisade fringe. All abdominal sternites shiny, with microstriae and punctures as those on tergites.

Male ( Figs 2-1E–J; 2-2A–E ). Head with small round elevation between eyes. Posterior margin of sternite VIII emarginate medially, emargination wide and shallow, each side with another shallower emargination ( Figs 2-1E; 2-2B ). Posterior margin of tergite VIII arcuate ( Figs 2-1F; 2-2C ). Tergite IX ( Figs 2-1G; 2-2D ) symmetrical, connected mediobasally, narrowed apically. Sternite IX ( Figs 2-1H; 2-2E ) symmetrical, widest near basal 1/3 to 1/2; basal margin straight, apical margin normally emarginated; width of apical margin slightly shorter than of basal margin. Tergite X ( Figs 2-1G; 2-2D ) symmetrical, triangular. Aedeagus ( Figs 2-1I–J; 2-2A ) symmetrical, medium-sized, ca. 0.59 mm long, normally sclerotized. Parameres symmetrical, thick and short, about 1/6 length of median lobe. Internal structures sclerotized, composed of five parts: U-shaped sclerite apically, symmetrical, brown color; paired strip shaped sclerites located on both sides, brown color; 3 sclerites in middle: paired oval sclerites in brown color, one irregular shaped sclerite in brown to black color. Sperm pump coiled, thinned toward apex.

Female ( Figs 2-2F–I ). Head without elevation between eyes. Sternite VIII ( Fig 2-2F ) with posterior margin rounded. Tergite IX bearing numerous setae, elongate and sharply pointed apically. Sternite IX ( Fig 2-2H ) almost symmetrical, with deep concave margin in middle. Tergite X broad, basal margin curved. Sternite X ( Fig 2-2G ) slender and rhomboidal, with numerous setae in lower half. Tube of spermatheca sclerotized, very long and strongly coiled ( Fig 2-2I ).

Distribution. Queensland.

Diagnosis. The species can be easily distinguished from others by its large body size and the yellow color of its pronotum and elytra ( Fig 2-1 ).

Etymology. The species epithet is dedicated to the collector of the type material, Mr. Y. Basset ( Switzerland).

Figures

FIGURE 2-2. Diochus basseti sp. nov.: A. aedeagus, dorsal view; B. male sternite VIII; C. male tergite VIII; D. male tergites IX–X; E. male sternite IX; F. female sternite VIII; G. female sternite X; H. female sternite IX; I. spermatheca. (Scale bars: 0.1 mm).