Syleter, Andrewes, 1941

Balkenohl, Michael, 2021, Revisiting the Oriental genus Syleter Andrewes, 1941 (Coleoptera: Carabidae: Clivinini), Revue suisse de Zoologie 128 (2), pp. 357-374 : 359

Identification key to the species of the genus Syleter

1A Labrum 3-setose; pronotum without reticulation and punctures on disk, with posterior angle rounded off; elytron with all intervals smooth, without tubercle at declivity of third interval, striae narrow, with punctures distinct, umbilical setigerous punctures with wider distance at middle; aedeagus at apex spoon-like widened, parameres with four setae each. Body length 2.8 mm. Borneo (central and southeast) ......................................... S. fulvaster

1B Labrum 7-setose; pronotum with reticulation and with or without punctures on disk, with posterior angle more or less marked; elytron with all or with interval eight reticulated, with tubercle at declivity of third interval, striae wide, finely crenulated, with punctures indistinct, umbilical setigerous punctures of equal distance; aedeagus at apex securiform widened or spatulate, parameres without or with two setae each ................................................ 2

2A Head anterior eye-level moderately elongated; neck constriction complete and developed as sharp angular step with level distinctly higher than neck; lateral channel of pronotum from posterior angle to base distinctly widened; apex of aedeagus developed as acute spatula, parameres with two setae each. Body length 3.61-3.64 mm. Myanmar.. ............................................................................................................................................................. S. acutipalpis

2B Head anterior eyes conspicuously elongated; neck constriction incomplete and developed as row of punctures, with a more or less wide gap at middle and with posterior part of frons at middle as high as neck or developed as rounded step and complete; lateral channel of pronotum from posterior angle to base narrow ............................. 3

3A Disk of pronotum without punctures; anterior margin of labrum straight; supraorbital plate covered with distinct longitudinal reticulation; interval eight of elytron with more or less distinct reticulation; apex of aedeagus developed as wide spatula. Body length 3.37-3.8 mm. Borneo ................................ S. sinepunctatus sinepunctatus sp. nov. o Specimen from West Malaysia: Lateral margin of elytron convex with maximum width at middle; intervals five to seven of elytron with indistinct reticulation; apex of aedeagus acutely pointed at tip and turns to a different direction as in the nominotypical subspecies. Body length 3.45 mm. Jahore, Kluang ........................................ ............................................................................................................... S. sinepunctatus kluangensis ssp. nov.

3B Disk of pronotum with punctures; anterior margin of labrum convex; supraorbital plate smooth; interval eight of elytron or all intervals with reticulation; apex of aedeagus developed either as narrow acuminated spatula or securiform ............................................................................................................................................................... 4

4A Disk of pronotum laterally with few single punctures in the basal part; anterior margin of pronotum distinctly excised, anterior angle projecting; apex of aedeagus developed as narrow acuminated spatula; Body length 3.32- 3.6 mm. New Guinea and Papua-New Guinea, Northeast Australia (Queensland): Cape York ................ S. papua

4B Disk of pronotum with numerous punctures arranged laterally as paramedian and paralateral group; anterior margin of pronotum straight, anterior angle not projecting; apex of aedeagus securiform ................................................ 5

5A All intervals of elytron longitudinally reticulated; pronotum with paramedian and paralateral band of punctures extending from anterior fifth to basal declivity; neck constriction complete and developed as rounded step; apex of aedeagus broadly securiform, stout. Body length 4.25-4.66 mm. Borneo .................................. S. gradus sp. nov.

5B Interval eight of elytron longitudinally reticulated (in some cases also interval seven); pronotum with more or less circular paramedian and paralateral group of punctures restricted to basal half; neck constriction incomplete and developed as lateral punctures with more or less wide gap in between; apex of aedeagus long securiform. Body length 3.51-4.32 mm. Hong Kong, Thailand, Cambodia, Vietnam (South), Malaysia, Singapore.......................... ............................................................................................................................... S. paradoxus (= S. trapezicollis )