Cephennium MÜLLER & KUNZE, 1822

Assing, Volker, Brachat, Volker & Meybohm, Heinrich, 2019, Monograph of the Staphylinidae of Crete (Greece). Part II. Descriptions of new species (Insecta: Coleoptera), Beiträge Zur Entomologie = Contributions to Entomology 69 (2), pp. 239-289 : 266-272

Genus Cephennium MÜLLER & KUNZE, 1822

The speciose genus Cephennium is distributed in the West Palaearctic region eastwards to Middle Asia and included nearly 150 species and several subspecies assigned to six subgenera; for the species known at the end of 2014 see SCHÜLKE and SMETANA (2015). According to JALOSZYŃSKI & STEVANOVIĆ (2015), who also illustrate the general distribution of the genus known at present, the current subgeneric concept is problematic and largely artificial. Most Cephennium species are locally endemic. Not a single species had been reported from Crete.

Recent field trips to Crete have yielded a substantial number of Cephennium specimens, the vast majority of them collected by washing soil in winter and early spring, suggesting an essentially subterranean habitat. An examination of the material collected with males revealed that they belong to twelve species, all of which are described below. Some additional females remain unnamed for the time being. They may represent additional species, but since the aedeagus is indispensable for a reliable identification, their identity requires clarification based on males. In view of the problematic subgeneric concept currently in use, none of the newly described species is assigned to one of the existing subgenera. All Cretan Cephennium species are anophthalmous or microphthalmous, apterous, and weakly pigmented.

Based on external characters and on the morphology of the aedeagus, the Cretan species are assigned to three species groups, the C. arcuatum group, the C. sinuosum group, and the C. chanianum group.

The C. arcuatum group includes five species, two ( C. selinonum , C. meybohmi ) from West Crete, one ( C. idanum ) from Central Crete, and two ( C. arcuatum , C. thripticum ) from East Crete. They are characterized by intermediate body size, a distinctly oblong antennomere XI (approximately 1.5 times as long as broad), eye rudiments with one to five weakly defined ommatidia without pigmentation, a pronotum with fine, but distinct punctation at least in posterior portion (where it is more distinct than that of elytra), elytra with a pronounced antero-lateral fold (process) and with a rather distinct and long humeral sulcus (fold), and an aedeagus with a short and apically smoothly convex ventral process (ventral view). Cephennium kerpense MEYBOHM, 2016 from Karpathos probably belongs to this group, too, but is distinguished from the Cretan representatives by the shape of the apical margin of the ventral process of the aedeagus (not smoothly convex in ventral view). Females representing one to three additional species from West and East Crete remain undescribed for want of males.

The C. sinuosum group includes six species from East and Central Crete ( C. sinuosum , C. fortespinosum , C. hamulatum , C. curvatum , C. selenanum , C. latius ). They are distinguished from the otherwise similar species of the C. arcuatum group by a short, conical, and weakly oblong antennomere XI, completely reduced eyes (ommatidia absent), extremely fine punctation of the pronotum, elytra with a weakly pronounced antero-lateral fold (process) and a fine humeral sulcus, and an aedeagus with a mostly longer and apically pointed ventral process (ventral view), and with a sclerotized ring-shaped basodorsal internal structure.

The C. chanianum group includes only C. chanianum from West Crete. It is characterized by larger body size, relatively long antennae with a distinctly oblong antennomere XI, completely reduced eyes (ommatidia absent), an anteriorly strongly dilated pronotum, extremely fine pronotal punctation, elytra with a somewhat obtuse antero-lateral fold and with a distinct humeral sulcus (fold), and a relatively large aedeagus with a rather long, slender, and sinuate (lateral view) ventral process and with large and strongly sclerotized internal structures.

Key to the Cephennium species of Crete

1. Slightly larger species: body length> 1.0 mm; width of elytra> 0.43 mm. Pronotum more strongly dilated in anterior half ( Fig. 127 ). Eyes completely absent. Aedeagus of distinctive shape ( Figs 128–129 ). West Crete. ......... chanianum

– Smaller species: body length ≤ 1.0 mm; width of elytra ≤ 0.42 mm. Pronotum weakly dilated in anterior half. Aedeagus of completely different morphology ............................................................................................................... 2

2. Antennomere XI at least approximately 1.5 times as long as broad ( Figs 102, 106 ). Eye rudiments present, composed of one to five ommatidia without pigmentation. Punctation of pronotum fine, but at least in posterior portion distinct, more distinct than that of elytra. Ventral process of aedeagus short, broad, and apically convex in ventral view; internal sac without sclerotized ring-shaped dorsal structure. Cephennium arcuatum group. ...................... 3

– Antennomere XI short and conical, only weakly oblong ( Fig. 114 ). Eyes completely absent. Punctation of pronotum extremely fine, indistinct, similar to that of elytra. Ventral process of aedeagus longer, less broad, apically pointed in ventral view; internal sac with sclerotized ring-shaped dorsal structure. Species from Central and East Crete. Cephennium sinuosum group. ............................................................................................................................................ 7

3. Species from West and Central Crete. .............................................................................................................................. 4

– Species from East Crete. ..................................................................................................................................................... 6

4. Species from Central Crete (Psiloritis). Aedeagus as in Figs 111–113 . ............................................................ idanum

– Species from West Crete. Aedeagus different .................................................................................................................. 5

5. Species from Southwest Crete. Aedeagus as in Figs 107–108 , internal sac with two pairs of larger spines in internal sac, without additional smaller spines. ............................................................................................................. selinonum

– Species from the region to the southwest of Chania. Aedeagus as in Figs 109–110 , internal sac with two pairs of larger spines and with numerous additional smaller spines. ......................................................................... meybohmi

6. Distribution: Orno Thriptis in the extreme east of Crete. Aedeagus as in Figs 104–105 . ........................ thripticum

– Distribution: Dikti range. Aedeagus as in Figs 102–103 ................................................................................. arcuatum

7. Species from Central Crete (Psiloritis). Antenna 0.45 mm long. Aedeagus with ventral process broad (ventral view), somewhat resembling a house in cross-section, and with internal structures of distinctive shapes ( Figs 125–126 ). ........................................................................................................................................................................................ latius

– Species from East Crete. Antenna shorter. Aedeagus with ventral process either stout and not house-shaped or more slender in ventral view, and with internal structures of different shapes. ......................................................... 8

8. Aedeagus with very broad (ventral view) and stout (lateral view) ventral process and with internal structures of distinctive shapes ( Figs 118–119 ). Known only from Zakros in the extreme east of Crete. .............. fortespinosum

– Aedeagus with more slender and less stout ventral process; internal structures different. ....................................... 9

9. Slightly larger species: body length 0.92–0.99 mm; width of pronotum 0.37–0.39 mm; width of elytra 0.39–0.40 mm. Internal structures of aedeagus distinctly curved ( Figs 115–117 ). East Crete: environs of Sitia. .............. sinuosum

– Slightly to distinctly smaller spccies. Internal structures of different shape. ............................................................ 10

10. Smaller species: body length ≤ 0.90 mm. Aedeagus with three pairs of long and nearly straight internal spines, the lateral spines with a small hook ( Figs 120–121 ). East slope of Dikti range (environs of Kritsa). ......... hamulatum

– Slightly larger species: body length> 0.90 mm. Aedeagus with internal structures of different shapes. .............. 11

11. Ventral process of aedeagus with longer and more pointed apex; internal sac with shorter spines, two of them strongly curved in ventral view ( Fig. 122 ). North slope of Orno Oros in the extreme east of Crete. ....... curvatum

– Ventral process of aedeagus less strongly pointed apically; internal sac with six long and only apically slightly curved spines ( Figs 123–124 ). Selena Oros to the southeast of Malia. .................................................................... selenanum

Figures

Figs 127–142: Cephennium chanianum (127–129), Euconnus zakrius (130), Stenichnus brachati (131–133), S. orientalis (134–136), S. aegialioides (137–138), S. aegialius (139–140), and S. godarti (141–142): habitus (127, 134); aedeagus in lateral, ventral, and dorsal view (128–130, 132, 136–137, 139, 141); male abdomen in ventral view (131, 135); spermatheca (133, 138, 140, 142). Scale bars: 127, 134: 0.5 mm; 131, 135: 0.2 mm; 128–130, 132–133, 136–142: 0.1 mm.

Figs 100–113: Gabrius candicus (100–101) and Cephennium spp. of the C. arcuatum group: C. arcuatum (102–103), C. thripticum (104–105), C. selinonum (106–108), C. meybohmi (109–110), and C. idanum (111–113): male sternite VIII (100); female abdominal segments IX–X (101); habitus (102, 106); aedeagus in lateral and in ventral view (103–105, 107–113). Scale bars: 102, 106: 0.5 mm; 100–101: 0.2 mm; 103–105, 107–113: 0.1 mm.

Figs 114–126: Cephennium spp.of the C. sinuosum group:C. sinuosum (114–117), C. fortespinosum (118–119), C. hamulatum (120– 121), C. curvatum (122), C. selenanum (123–124), and C. latius (125–126): habitus (114); aedeagus in lateral and in ventral view (115–126). Scale bars: 114: 0.5 mm; 115–126: 0.1 mm.