Hlavaciellus, Jaloszynski

Jałoszyński, Paweł, 2021, Six new species of the Oriental genus Hlavaciellus Jałoszyński (Coleoptera Staphylinidae, Scydmaeninae), Zootaxa 4966 (1), pp. 1-15 : 12-13

Identification key to males of Hlavaciellus species

[Measurements should be taken as explained in Materials & methods; proportions of body parts important for identification are compiled in Table 1 .]

1 Antennae conspicuously short (AnL/BL below 0.5) and strongly clavate, with antennomere 11 about as long as 8–10 together. [ Nepal]................................................................. Hlavaciellus primitivus Jałoszyński

- Antennae long (AnL/BL over 0.5) and massive, weakly thickeneing distad, with antennomere 11 much shortr than 8–10 together. [SE Asia]...................................................................................... 2

2 Head with distinct, broadly U-shaped carina convex anteriorly and demarcating median region of vertex and frons. [ Malaysia: Pahang].............................................................. Hlavaciellus peninsularis Jałoszyński

- Head lacking U-shaped carina convex anteriorly............................................................. 3

3 Head between eyes with transverse carina bearing some setae and demarcating glossy posterior asetose transverse impression and anterior, also glossy and asetose region of frons.......................................................... 4

- Head lacking setose transverse carina between eyes demarcating posterior and anterior glossy asetose regions............ 5

4 Asetose transverse impression behind eyes with pair of tiny submedian tubercles; asetose median region of frons with broadly separated lateral impressions; body length exceeding 2 mm. [ Malaysia: Pahang]........ Hlavaciellus carinatus Jałoszyński

- Asetose transverse impression behind eyes lacking pair of submedian tubercles; asetose median region of frons with narrowly separated submedian impressions; body length below 1.9 mm. [ Malaysia; Sabah]...... Hlavaciellus decoratus Jałoszyński

5 Head between eyes with impression occupying almost entire vertex and filled with short dense setae directed toward its center. [ Indonesia: Sumatra]....................................................... Hlavaciellus concavus Jałoszyński

- Head lacking large impression filled with short and dense setae................................................. 6

6 Vertex behind eyes with two pairs of tiny tubercles forming trapeze, between upper tubercles with slender ‘lock’ of dense long setae curved anterad. [ Malaysia: Sabah]....................................... Hlavaciellus cincinnalis Jałoszyński

- Vertex behind eyes with one pair of tubercles or lacking tubercles, lacking median tuft of long setae curved anterad....... 7

7 Vertex between eyes with median conical tubercle and distinct transverse groove just behind tubercle. [ Malaysia: Sabah]........................................................................... Hlavaciellus sabahensis Sevanović

- Vertex lacking median tubercle and lacking transverse groove.................................................. 8

8 Vertex between eyes with pair of large round tubercles, each much broader than one ommatidium. [ Malaysia: Sabah].............................................................................. Hlavaciellus vampirus Jałoszyński

- Vertex either lacking tubercles or with tubercles about as wide as single ommatidium............................... 9

9 Vertex between or above eyes with median group of remarkably long or/and dense setae............................ 10

- Vertex lacking median group of particularly long or dense setae............................................... 11

10 Body length over 2 mm; EL/PL not exceeding 1.7; pronotum slightly broader than elytra; posterior margin of frons between posterior margins of eyes at each side with arcuate (posteriorly convex) ridge; vertex with shallow transverse postocular impression; parameral apex in lateral view with deeply S-shaped posterior margin. [ Indonesia: Sumatra]......................................................................................... Hlavaciellus sumatranus Jałoszyński

- Body length below 2 mm; EL/PL exceeding 1.8; pronotum and elytra equally broad; posterior margin of frons between posterior margins of eyes at each side lacking arcuate ridge; vertex lacking transverse postocular impression; parameral apex in lateral view with straight posterior margin. [ Malaysia: Sarawak]....................... Hlavaciellus cirrus Jałoszyński

11 Head with pair of deep and broad impressions running from posterior margin of each eye anteromesad, between and in front of eyes impressions demarcate median longitudinal elevation. [ Malaysia: Sabah].......................................................................................................... Hlavaciellus angustifrons Jałoszyński

- Frons lacking median longitudinal elevation demarcated laterally by impressed areas............................... 12

12 Head behind eyes either with continuous or nearly continuous transverse impression or with pair of impressions separated at middle............................................................................................. 13

- Head behind eyes not impressed......................................................................... 17

13 Head with uniterrupted transverse impression.............................................................. 14

- Head with pair of shallow lateral impressions clearly separated at middle........................................ 15

14 Body length over 1.8 mm; antennomeres 3–5 each at least slightly longer than broad; aedeagus in ventral view stout, less than 3 times as long as broad; paramere in lateral view with slender and weakly, gradually curved apex. [ Malaysia: Sabah]............................................................................. Hlavaciellus smetanai Jałoszyński

- Body length below 1.7 mm; antennomeres 3–5 each subquadrate; aedeagus in ventral view slender, 4 times as long as broad; paramere in lateral view with bent and subapically broadened distal portion with angulate ventral margin. [ Philippines: Palawan]........................................................................................................................................................................ Hlavaciellus promissor Jałoszyński

15 Shallow impressions on vertex adjacent to posterior margins of eyes, convex area between them about as wide as each impression; body length only 1.6 mm or even slightly less. [ Malaysia: Sarawak].......... Hlavaciellus diversipilosus Jałoszyński

- Shallow impressions on vertex broadly separated from posterior margins of eyes, convex area between them narrower than each impression; body length over 1.8 mm ..................................................................... 16

16 Antennomere 3 nearly twice as long as broad; body length 2 mm or slightly more. [ Malaysia: Sabah].......................................................................................... Hlavaciellus bifoveatus Jałoszyński

- Antennomere 3 about as long as broad; body length below 1.9 mm. [ Malaysia: Sabah]... Hlavaciellus adelphos Jałoszyński

17 Subhumeral lines on elytra vestigial, barely discernible; antennomeres 6 and 7 each twice as long as broad. [ Malaysia: Sabah]...................................................................... Hlavaciellus extremalis Jałoszyński

- Subhumeral lines on elytra sharply marked, at least as long as 0.3 EL; each of antennomeres 6 and 7 clearly shorter than twice as long as broad..................................................................................... 18

18 Elytra conspicuously short, indistinctly broader than long, with EI 0.95; vertex behind eyes with pair of tiny but distnct tubercles. [ Malaysia: Pahang].......................................... Hlavaciellus microtuberculatus Jałoszyński

- Elytra clearly elongate, with EI exceeding 1.2; vertex behind eyes lacking pair of tubercles.......................... 19

19 Antennomere 11 2.2 × as long as broad; aedeagus in ventral view bottle-shaped, with distal 1/3 clearly narrower than basal half and with sinuate sides. [ Malaysia: Sabah]......................................... Hlavaciellus miser Jałoszyński

- Antennomere 11 less than twice as long as broad; aedeagus in ventral view not bottle-shaped, with apical region gradually narrowing distad and with rounded side..................................................................... 20

20 EL/PL 2.2; PW/PL 1.45; elytra broader than pronotum; aedeagus stout, 3 times as long as broad; subapical region of paramere distinctly broadened. [ Malaysia: Sabah]......................................... Hlavaciellus metrios Jałoszyński

- EL/PL below 2; PW/PL clearly below 1.4; pronotum and elytra equal in width; aedeagus slender, nearly 4 times as long as broad; subapical region of paramere not broadened. [ Malaysia: Sabah]............ Hlavaciellus clandestinus Jałoszyński