Scaphisoma Leach, 1815

Löbl, Ivan, 2015, On the Scaphidiinae (Coleoptera: Staphylinidae) of the Lesser Sunda Islands, Revue suisse de Zoologie 122 (1), pp. 75-120 : 92-94

Scaphisoma Leach, 1815

Comments: Scaphisoma is with over 600 species currently recognized as valid the most species-rich genus of the subfamily Scaphidiinae . Not surprisingly, it is with 24 encountered species also quite diverse in the Lesser Sunda Islands. All have well developed hind wings suggesting dispersal ability and possible wide distribution.

Key to the Scaphisoma species of the Lesser Sunda Islands

1 Elytra with sutural striae conspicuously strongly converging apically .................................................................... 2

– Elytra with sutural striae parallel, or to large extent parallel, or weakly converging apically ................................. 4

2 Pronotum and elytral disc with similar, very fine punctation. Pronotum and most of elytra very dark reddish-brown to black, apical fourth of elytra yellowish ...................................................................................... S. jacobsoni Löbl

– Elytral disc with punctation much coarser than pronotal punctation. Colour pattern of pronotum and elytra different..................................................................................................................................................................... 3

3 Pronotum bicoloured in male, dark brown to black in female. Elytra dark with light subhumeral spot and light subapical fascia. Antennomere III subcylindrical, elongate ....................................................... S. aspectum sp. nov.

– Pronotum light, yellowish or reddish-brown in both sexes. Elytra light on prevailing surface, darkened along suture, basal margins and on transverse band posterior mid-length. Antennomere III subtriangular, short .............. ............................................................................................................................................................ S. dohertyi Pic

4 Elytra light on prevailing surfaces, darkened along lateral margin, base and sutural striae, each elytron with small, isolated, dark discal spot.................................................................................................................... S. sapitense Pic

– Colour pattern of elytra different.............................................................................................................................. 5

5 Elytra with sutural striae extending along basal margins to form basal striae ......................................................... 6

– Elytra with sutural striae not extending along basal margin and without basal striae.............................................. 8

6 Antennomere V longer than III and IV combined, and much shorter than antennomere VIII .. S. acutatum sp. nov.

– Antennomere V as long as III and IV combined, almost as long as antennomere VIII ........................................... 7

7 Body 1.55-1.60 mm long, uniformly reddish brown, elytra with shallow basal striae .............. S. lombokense Löbl

– Body 1.90 mm long. Pronotum dark reddish-brown, elytra coloured as pronotum along bases, apices, sutural striae and lateral margin, most of elytra much lighter, forming large reddish spot..................................... Scaphisoma sp.

8 Basomedian area of sternite 1 coarsely punctate. Metaventrite with antecoxal puncture rows. Elytra coarsely punctate, light in apical third, with sutural striae abruptly obliquely bent near base .................. S. affectum sp. nov.

– Basomedian part of sternite 1 very finely punctate .................................................................................................. 9

9 Metaventrite with median groove...........................................................................................................................10

– Metaventrite without median groove......................................................................................................................13

10 Elytra and pronotum uniformly coloured ............................................................................................................... 11

– Apical third of elytra clearly lighter than remaining elytral surface and pronotum ............................................... 12

11 Pronotum and elytra reddish-brown. Submesocoxal areas about as long as submetacoxal areas S. aequum sp. nov.

– Pronotum and elytra blackish-brown to black. Submesocoxal areas clearly longer than submetacoxal areas .......... ....................................................................................................................................................... S. aereum sp. nov.

12 Antennomeres III and IV combined shorter than V ................................................................. S. adjunctum sp. nov.

– Antennomeres III and IV combined longer than V ...................................................................... S. ablutum sp. nov.

13 Submetacoxal areas conspicuously large, extending onto apical half of sternite.................. S. antennarum sp. nov.

– Submetacoxal areas not extending onto apical half of sternite ..............................................................................14

14 Hypomera with striate microsculpture. Anterior two thirds of elytra with conspicuous coarse punctation, apical third to two fifth of elytra smooth, appearing impunctate .............................................................. S. rufescens (Pic)

– Hypomera not microsculptured. Elytral punctation different.................................................................................13

15 Median part of metaventrite with strigulate microsculpture ..................................................................................16

– Metaventrite not microsculptured...........................................................................................................................19

16 Median part of metaventrite much coarser punctate than lateral parts, or than sternite 1, metaventrite with distinct antecoxal puncture rows .............................................................................................................. S. sesaotense Löbl

– Median and lateral parts of metaventrite with similar, very fine punctation ..........................................................17

17 Larger species 1.93-2.10 mm long. Elytra black, somewhat lighter along base and on adsutural areas and with narrowly yellowish apices ............................................................................................................ S. angular sp. nov.

– Smaller species, 1.25-1.60 mm long. Colour pattern of elytra different ................................................................18

18 Internal sac of aedeagus with mesal row of large, triangular sclerites, long lateral denticles fused to form plates and tuft of apical denticles covered by membranous spine-like structures................................... S. luteomaculatum Pic

– Internal sac of aedeagus with few long lateral sclerites, lacking mesal row of triangular sclerites ........................... ............................................................................................................................ S. obliquemaculatum Motschulsky

19 Elytra and pronotum with similar, very fine punctation ......................................................................................... 20

– Elytral punctation distinctly coarser than pronotal punctation, eventually near bases similar to pronotal, on most surface coarser ........................................................................................................................................................ 21

20 Antennomere IV about twice as long as III, combined with III about as long as V.................... S. coarctatum Löbl

– Antennomere IV about three times as long as III, combined with III distinctly longer than V ... S. affabile sp. nov.

21 Pronotum and elytra on basal part of disc and on transverse subapical band dark brown or reddish-brown, most of elytral disc and narrow apical band light, yellowish. Submetacoxal areas large, almost reaching sternal midlength ......................................................................................................................................... S. animatum sp. nov.

– Elytral colour different. Submetacoxal areas narrower ..........................................................................................22

22 Sternite 1 with much coarser punctation than that on metaventrite, submetacoxal lines parallel.............................. ........................................................................................................................................... S. approximatum sp. nov.

– Sternite 1 about as metaventrite very finely punctate, submetacoxal lines convex................................................23

23 Elytral punctation fine, in particular on basal halves, consisting of poorly delimited punctures. Apical two fifth somewhat lighter than basal two fifth of elytra ...................................................................... S. gracilicorne Achard

– Elytral punctation distinct, fairly coarse, consisting of well delimited punctures. Elytra becoming lighter only near apical margins .........................................................................................................................................................24

24 Antennomere IV about 4.5 times as long as III. Submetacoxal lines reaching sternal mid-length............................ .................................................................................................................................................... S. adscitum sp. nov.

– Antennomere IV about 2.5 times as long as III. Submetacoxal lines not reaching sternal mid-length..................25

25 Aedeagus with wide apical process and bases of parameres strongly widened. Elytral punctation very fine along lateral margins, fairly coarse on most of discal surface................................................................ S. activum sp. nov.

– Aedeagus with narrow apical process and bases of parameres moderately widened. Elytral punctation fairly coarse, including on surfaces along lateral margins .................................................................................. S. acutum sp. nov.