Trechus Clairville 1806
Creators: name: Schmidt, Joachim
name: Faille, Arnaud
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Trechus

description: Key to the species of Trechus from the Arussi and Bale Provinces of Ethiopia
1. Males with only one basal protarsomere dilated .............................................................................. 2 – Males with two basal protarsomeres dilated ................................................................................... 10
2. Disc of elytra with at least 4–5 internal striae distinctly engraved. Antennae slenderer with antennomeres 7–9 1.6–1.8 times as long as wide. Species from southern slope of Bale Mts …3
– Elytral discal striae very finely engraved, usually indistinct with first stria often absent. Antennae short with antennomeres 7–9 1.2–1.4 times as long as wide ............................................................ 4
3. Each elytron with a single dorsal seta (both posterior discal seta on third stria and preapical seta are absent). Pronotum with laterobasal angles very obtuse, blunt at tip, and with laterobasal impressions indistinct; lateral gutter of pronotum not widened near base ................... T. transversicollis sp. nov.
– Two elytral discal setae present. Pronotum with laterobasal angles slightly obtuse, sharp at tip, and with laterobasal impressions broad; lateral gutter of pronotum distinctly widened towards base ......................................................................................................................... T. mattisi sp. nov.
4. Elytra with preapical seta absent. Species of Mt Enkuolo with body colour of mature specimens light brown ................................................................................................................................................ 5
– Elytra with preapical seta present (situated at the apical anastomosis of second and third striae). Species of the Bale Mts; body colour of mature specimens usually brown to dark brown .............. 6
5. Each elytron with two dorsal setae on third stria in normal position ................................................. ........................................................................................ T. gypaeti Vigna Taglianti & Magrini, 2010 – The posterior elytral dorsal seta is lacking ................................................... T. minitrechus sp. nov.
6. Apex of terminal lamella of aedeagal median lobe simply tapered or with a small globose apical capitulum .......................................................................................................................................... 7 – Median lobe of aedeagus with a distinct button-like apical capitulum (Figs 45, 47, 48) ................. 8
7. Eyes slightly larger than tempora. Aedeagal median lobe stouter (Fig 43) .......... T. nanulus sp. nov. – Eyes slightly smaller than tempora. Aedeagal median lobe more elongated (Fig 44) ........................ ...................................................................................................................................... T. rira sp. nov.
8. Aedeagal median lobe in lateral view with ventral margin sinusoidal (Fig 47) ................................. ...................................................................... T. relictus Magrini, Quéinnec & Vigna Taglianti, 2012 – Aedeagal median lobe in lateral view with ventral margin concave or straight ............................... 9
9. Aedeagal median lobe robust in view from laterad and dorsad (Figs 48–49) .... T. oppositus sp. nov. – Aedeagal median lobe slender in view from laterad and dorsad (Figs 45–46) .. T. iridescens sp. nov.
10. Body length <3.5 mm and eyes rather small, tempora at least 0.7 times as long as eyes, first stria of elytra indistinctly impressed or absent, microsculpture of elytra with very finely engraved very transverse meshes ............................................................................................................................11
– Either body length ± 3.5 mm, or eyes rather large, tempora at maximum 0.5 times as long as eyes, first stria of elytra distinctly impressed, microsculpture of elytra with distinctly engraved isodiametric or slightly transverse meshes .............................................................................................................. 15
11. Body length approximately 3.2–3.3 mm. Aedeagal median lobe slenderer, with terminal lamella long, markedly bent upward at tip (Fig. 56) ............................................................ T. bombi sp. nov.
– Body length below 3.0 mm. Aedeagal median lobe rather stout, with terminal lamella moderately short, at most slightly bent upward at tip ........................................................................................ 12
12. Endophallus very slightly sclerotized throughout, without suggestion of a copulatory piece even in view from laterad (Fig. 53). Species from northern slope of western Bale Mts above the city of Adaba ....................................................................................................................... T. adaba sp. nov.
– Endophallus with a more markedly sclerotized part near dorsoapical ostium which is easily recognizable in lateral view ............................................................................................................ 13
13. Aedeagal median lobe in lateral view suggestively sinusoidal with ventral margin slightly convex in apical half (Fig. 55). Species from southeastern slope of Bale Mts .................... T. harenna sp. nov.
– Median lobe in lateral view with ventral margin evenly curved throughout or straight in apical half .................................................................................................................................................. 14
14. Aedeagal median lobe markedly short (EL/AL = 3.96–4.16), in lateral view almost evenly bent throughout (Fig. 52). Species from northern slope of western Bale Mts above the city of Dodola ..................................................................................................................... T. dodola sp. nov.
– Aedeagal median lobe more elongated (EL/AL = 3.03–3.22), in lateral view with ventral margin straight in apical half (Fig. 50). Species from southern slope of eastern Bale Mts, near the village of Rira .......................................................................................................................... T. harryi sp. nov.
15. Each elytron with a single discal seta which inserts near the end of the anterior elytral quarter ... 16 – Each elytron with two discal setae, the anterior one near the end of the anterior elytral quarter, the posterior one near elytral middle .................................................................................................... 17
16. Pronotum with laterobasal setae absent. Species from Mt Chillalo ............. T. patrizii Jeannel, 1960 – Pronotum with laterobasal setae present. Species from Mt Chillalo, Mt Enkuolo, and northern slope of Bale Mts ............................................. T. oromiensis Magrini, Quéinnec & Vigna Taglianti, 2012
17. Eyes flat and very small, tempora as long as or longer than eyes .................................................. 18 – Eyes moderately large and convexly protruded laterally, tempora distinctly shorter than eyes ..... 19
18. Aedeagal median lobe markedly funnel-shaped, widened near apex (Jeannel 1936: 209). Species from Mt Chillalo .............................................................................................. T. scotti Jeannel, 1936
– Aedeagal median lobe simply narrowed towards apex (Geginat 2008: 125). Species from the Bale Mts ............................................................................................... T. clarkeianus (Basilewsky, 1974)
19. Body length> 5.1 mm (usually> 5.5 mm) and endophallus extensively sclerotized with total length of sclerotized portions more than half of length of aedeagal median lobe (Geginat 2008: 125, fig. 5A–C) ....................................................................................................................................... 20
– Either body length <5.1 mm, or endophallus moderately sclerotized with total length of sclerotized portions approx. one third of length of aedeagal median lobe ....................................................... 22
20. Colour of dorsal surface mid-brown, elytra silk-matt, not iridescent; elytral microsculpture with meshes larger, more deeply engraved; aedeagal median lobe markedly elongated (Geginat 2008: 125, fig. 5A). Species from the Bale Mts ................................... T. rotundicollis (Basilewsky, 1974)
– Colour of dorsal surface dark or blackish brown, elytra markedly shiny, iridescent; elytral microsculpture with meshes narrower, more slightly engraved; aedeagal median lobe markedly robust (Geginat 2008: 125, fig. 5B–C) ........................................................................................... 21
21. Elytra with striae 1–4 very finely impressed and intervals flat; aedeagal median lobe in lateral view with ventral margin slightly but distinctly convex (Geginat 2008: 125, fig. 5C). Species from Mt Chillalo ................................................................................................... T. chillalicus Jeannel, 1936
– Elytra with striae 1–4 rather deeply impressed and intervals moderately convex; aedeagal median lobe in lateral view with ventral margin nearly straight (Geginat 2008: 125, fig. 5B). Species from the Bale Mts ..................................................................................... T. baleensis (Basilewsky, 1974)
22. Species from Mt Chillalo ................................................................................................................ 23 – Species from the Bale Mts .............................................................................................................. 24
23. Elytra shinier with meshes of microsculpture more finely engraved, narrower, more transverse; aedeagal median lobe with apex hook-like bent upward (Jeannel 1936: 207, fig. 2) ......................... ................................................................................................................... T. gallorites Jeannel, 1936
– Elytra silk-like matt with meshes of microsculpture more deeply engraved, larger, almost isodiametric; aedeagal median lobe with apex simple (Jeannel 1936: 208, fig. 5) .... T. culminicola Jeannel, 1936
24. Pronotum with basal margin slightly but distinctly concave at outer quarters, and with laterobasal angles large, acute, posteriorly and laterally protruded (Fig. 72). Species from the southern slope and the western part of the Bale Mts............................................................................ T. mekbibi sp. nov.
– Pronotum with basal margin straight or convexly rounded at outer quarters; laterobasal angles not protruded posteriad ......................................................................................................................... 25
25. Pronotum with basal margin straight or very slightly bent anteriorly at outer quarters, and with laterobasal angles acute or rectangular or formed as a rather large, +/- sharp tooth (Figs 71, 73– 74) ................................................................................................................................................... 26
– Pronotum with basal margin distinctly bent anteriorly at outer quarters, and with laterobasal angles rounded or formed as a small blunt tooth (Figs 83–86, 95–98, 108–110) ...................................... 29
26. Pronotum with laterobasal angles comparatively large and acute (Fig. 71). Elytra markedly depressed on disc; meshes of elytral microsculpture rather large, as wide as long or very slightly transverse. Species from northern slope of Bale Mts .................................................. T. depressipennis sp. nov.
– Laterobasal angles of pronotum smaller. Elytra more convex, at most slightly depressed on disc, with micro-meshes very narrow, distinctly transverse .................................................................... 27
27. Aedeagal median lobe in lateral view distinctly sinusoidal, markedly bent behind basal bulb and markedly convex in middle (Fig. 120). Species from the western Bale Mts ........ T. colobus sp. nov.
– Aedeagal median lobe in lateral view markedly elongated, slightly bent behind basal bulb and slightly convex or straight in middle (Fig. 118; Magrini & Sciaky 2006: 185, fig. 9). Species from the northern and southern slopes of the eastern Bale Mts .............................................................. 28
28. Aedeagal median lobe in dorsal view distinctly widened before apex (Magrini & Sciaky, 2006: 185, fig. 10), and with endophallic copulatory piece short, triangular. Species from northeastern slope of Bale Mts ................................................................................. T. bastianinii Magrini & Sciaky, 2006
– Aedeagal median lobe in dorsal view parallel before apex and with endophallic copulatory daggerlike (Fig. 119). Species from southeastern slope of Bale Mts .............................. T. hagenia sp. nov.
29. Microsculpture of elytra consists of rather large almost isodiametric meshes; elytra silk-shiny, not iridescent ......................................................................................................................................... 30 – Microsculpture with sculpticells narrow and transverse; elytra markedly shiny, iridescent .......... 32
30. Elytra with pores of discal setae conspicuously dimple-like, deepened ................. T. haggei sp. nov. – Elytral discal pores slightly impressed, normal for Trechus ........................................................... 31
31. Endophallus with sclerotized portions located in centre of aedeagal median lobe (Figs 126– 127) ........................................................................................................................ T. sanettii sp. nov.
– Endophallus with sclerotized portions located in anterior half of aedeagal median lobe (Figs 129– 130) .......................................................................................... T. batuensis Magrini & Sciaky, 2006
32. Pronotum comparatively large, elytra slenderer oval (proportion EW/PW below 1.45) ................ 33 – Markedly broad oval elytra contrasting with a rather small pronotum (proportion EW/PW above 1.5) .................................................................................................................................................. 35
33. Aedeagal median lobe slenderer, proportion EL/AL distinctly below 2.5 (Fig. 137) ........................ ....................................................................................................................... T. balesilvestris sp. nov. – Proportion EL/AL distinctly above 2.5 ........................................................................................... 34
34. Legs yellowish brown, femora not distinctly darkened; aedeagal median lobe in lateral view markedly widened near apical ostium (Fig. 135) ........................................... T. tragelaphus sp. nov.
– Basal three quarter of femora distinctly darkened; aedeagal median lobe in lateral view not widened near apical ostium (Fig. 136) ...................................................................... T. nigrifemoralis sp. nov.
35. Aedeagal median lobe markedly elongated with middle portion tube-like, in lateral and dorsal views with side margins straight and parallel in middle (Figs 122–123) .............. T. wiersbowskyi sp. nov.
– Aedeagal median lobe not tube-like, in lateral view with side margins not parallel, and with dorsal margin distinctly convex ................................................................................................................. 36
36. Aedeagal median lobe larger with total length about 1.4 mm ..................... T. grandipennis sp. nov. – Maximum length of aedeagal median lobe not above 1 mm .......................................................... 37
37. Aedeagal median lobe robust in lateral and dorsal view, with large basal bulb contrasting with markedly small sagittal aileron; endophallus more markedly sclerotized, with sclerotized portions distinctly longer than one third of total length of aedeagal median lobe (Magrini et al. 2013: 22, figs 2–4) ............................................................... T. ericalis Magrini, Quéinnec & Vigna Taglianti, 2013
– Aedeagal median lobe slenderer, with basal bulb and sagittal aileron average; endophallus less markedly sclerotized, with maximum length of sclerotized portions one third of total length of aedeagal median lobe ...................................................................................................................... 38
38. Aedeagal median lobe less markedly bent in basal portion, straight from the end of the basal third towards apex (Fig. 128) ................................................................................. T. angavoensis sp. nov.
– Aedeagal median lobe more markedly bent in basal portion, straight after beginning of the second third ................................................................................................................................................. 39
39. Aedeagal median lobe larger, total length 0.85–0.90 mm, with button-like apex more markedly bent upward at tip (Fig. 131) ................................................................................. T. abalkhasimi sp. nov.
– Aedeagal median lobe smaller, total length 0.70–0.80 mm, with button-like apex slightly bent upward at tip (Fig. 133) .......................................................................................... T. fisehai sp. nov.
description: Published as part of Schmidt, Joachim & Faille, Arnaud, 2018, Revision of Trechus Clairville, 1806 of the Bale Mountains and adjacent volcanos, Ethiopia (Coleoptera, Carabidae, Trechini), pp. 1-82 in European Journal of Taxonomy 446 on pages 76-79, DOI: 10.5852/ejt.2018.446, http://zenodo.org/record/3829902