Cheleion jendeki, Kral, David & Hajek, Jiri, 2015

Kral, David & Hajek, Jiri, 2015, A second species of Cheleion from Johor, Malaysia (Coleoptera, Scarabaeidae, Aphodiinae, Stereomerini), ZooKeys 532, pp. 87-97 : 88-94

Taxon classification Animalia Coleoptera Scarabaeidae

Cheleion jendeki sp. n. Figures 1, 3, 5, 7, 9, 11, 13-15, 17

Type locality.

Malaysia, Johor, Endau Rompin National Park, 02°37'12"N 103°21'00"E, 120-300 m a. s. l.

Type material.

Holotype: ♀, "Malaysia, Johor / Endau Rompin NP / N2.62, E103.35 / 28-31.v.2013, 120-300 m / E. Jendek & O. Šauša leg. [printed] // Cheleion jendeki sp. nov. / HOLOTYPUS ♀ / David Král & Jiří Hájek det. 2015 [red, printed]".

Description of female holotype.

Slightly convex, integument chestnut brown; head appendages and tarsi amber coloured; whole dorsal surface more or less covered with appressed lanceolate scales (Fig. 1).

Head (Figs 1, 3, 7) remarkably transverse, subrectangular in dorsal view, clypeus shiny, impunctate, apically pointed and reflexed under head, frons slightly convex with five straight, anteriorly divergent furrows; posterior transverse furrow across head between posterolateral corners of eyes; occiput with numerous small, longitudinal pits. Surface covered with dense appressed, lanceolate, approximately regularly spaced scales, individual scales separated from each other by less than their diameter (Fig. 7). Antennae long, length equal to width of head, with long macrosetae. Maxillary palpi length equal to length of head, with securiform ultimate palpomere. Labial palpi with long macrosetae apically. Eyes small but visible in dorsal view (Fig. 7).

Pronotum (Figs 3, 9, 13) large and transverse, anterior edge shallowly bisinuate, sides regularly, broadly rounded, posterior edge with broad medial protrusion. Pronotal disc with seven furrows medially, converging towards middle in hourglass pattern, mid furrow shallower than lateral furrows (Figs 3, 9). Anteromedial disc with distinctly raised knob, posteromedial disc and posterolateral sides with slightly lower, bulbous areas; anterolaterally of the furrows with large, flat elliptical depressions, de lineated by furrows. Knob posteriorly and bulbous areas anteriorly with tufts of long dense microtrichiae (= trichomes) (Fig. 13); surface covered with dense apressed, lanceolate, approximately regularly spaced scales, individual scales separated by less their diameter from each other anterolaterally and laterally; scales on knob and bulbous areas smaller and sparser; flat lateral areas with several sparse rather irregularly spaced scales only (Fig. 13).

Scutellar shield triangular, notably small (Fig. 11).

Elytra approximately as broad as pronotum and only slightly longer than pronotum and head combined; tapering posteriad, rounded apically. Each elytron with five longitudinal ridges before the lateral edge (Figs 1, 3, 11); ridges of approximately same height, elevated and almost continuous, consisting of longitudinal rows of almost confluent tubercles (Fig. 11); intervals (between ridges) flat, rugose, with irregularly circular pads, each pad bearing lanceolate scale on posterior edge, individual pads sepa rated by less their diameter from each other discally, becoming confluent into small rows or groups laterally, especially in humeral area (Figs 11, 14). Epipleura broadly inflexed; posterior two thirds of lateral edge slightly recurved (to allow free movement of metathoracic legs).

Legs short with broad femora and tibiae; tarsi short, tetramerous; claws weak, short, almost straight (Figs 5, 15, 17). Femora shiny, covered with coarse, dense, almost regularly spaced macrosetigerous punctures (Figs 15, 17). Protibiae moderately wide, with finely serrated outer edge and one strong apical lateral tooth, tarsus inserted well before apex (Fig. 15). Meso- and metatibiae broad with finely serrated outer edge and concave apex; each with two inconspicuous terminal spurs and two rows of thick short macrosetae on outer edge (Fig. 17).

Macropterous.

Pygidium exposed, strongly punctate proximally, less strongly apically, with small emargination on proximal pygidial border.

Venter. Prosternal process remarkably elevated, strongly expanded anteriad and posteriad (Figs 5, 15); anterior part grooved longitudinally and sinuate apically, posterior part hastate, surface rugose with marginal bead (Fig. 15). Mesoventrite narrow with alutaceous surface (Fig. 17). Metaventral plate flat, triangular, tapering, widest anteriorly, grooved along midline, surface alutaceous, covered with coarse, dense, almost regularly spaced macrosetigerous punctures (Fig. 17).

Five visible abdominal ventrites apparently fused, covered with coarse, dense, almost regularly spaced macrosetigerous punctures.

Measurements.

Total body length: 1.9 mm, width at broadest point 0.9 mm.

Differential diagnosis.

The new species is classified in the genus Cheleion mainly by the combination of the following characters: strongly tuberculate and rugose body surface, noticeably long antennae, pronotum with distinct anteromedial knob and bulbous areas medially and laterally and hastate posterior prosternal process. Cheleion jendeki sp. n. is similar and probably closely related to Cheleion malayanum , the only other known species of the genus, but clearly differs mainly as follows:

lateral longitudinal grooves on head straight (Figs 1, 3, 7) (weakly s-shaped in Cheleion malayanum (Figs 2, 4, 8));

sides of pronotum regularly rounded, maximum width of pronotum in midlength; posterior angles subrectangular (Figs 3, 9, 15) (sides of pronotum more attenuated in basal third, maximum width of pronotum in anterior third; posterior angles obtuse with apparent spiniform scales in Cheleion malayanum (Figs 4, 10, 16);

elytral surface at first sight moderately rugose (Figs 1, 3, 11) (more strongly rugose in Cheleion malayanum (Figs 2, 4, 12);

elytral ridges distinctly elevated (Figs 3, 11) (almost flat in Cheleion malayanum (Figs 4, 12);

elytral ridges continuous, consisting of longitudinal rows of almost confluent tubercles; lateral ridges indistinct (Fig. 3) (rather discontinuous, consisting of tubercles with scanty longitudinal groups of tubercles with scales; all elytral ridges distinct in Cheleion malayanum (Fig. 4));

pads on elytral intervals separated by less their diameter and mostly arranged as triseriate discally (Fig. 11) (confluent to subconfluent and mostly arranged as biseriate in Cheleion malayanum (Fig. 12));

marginal bead of posterior part of prosternal process rounded apically (Fig. 15) (angulate apically in Cheleion malayanum (Fig. 16)).

In spite of clear differences mentioned above, we are aware that only single specimens are known for each Cheleion species. In addition, both type localities are placed only about 200 km apart, without any distinct barrier between them. Thus, we cannot exclude the possibility that morphological differences of Cheleion jendeki sp. n. represent only an intraspecific variability of Cheleion malayanum , but we consider it quite improbable.

Etymology.

Patronymic; named in honour of our colleague and friend Eduard Jendek (Ottawa, Canada), excellent student in Buprestidae and collector of the holotype.

Distribution.

So far known only from the type locality in the Johor Province of continental Malaysia.

Collecting circumstances.

Flight intercept trap exposed inside lowland primary tropical forest (Fig. 19; E. Jendek, pers. comm. 2015).