A New Species of Trechus from the Ethiopian Highlands (Coleoptera: Carabidae: Trechinae) and Key to the Trechus Species of Ethiopia

SYSTEMATICS A New Species of Trechus From the Ethiopian Highlands (Coleoptera: Carabidae: Trechinae) and Key to the Trechus Species of Ethiopia VICENTE M. ORTUN ˜O 1 AND FRANCISCO NOVOA 2 Ann. Entomol. Soc. Am. 104(2): 132Ð140 (2011); DOI: 10.1603/AN10122 ABSTRACT The enormous genus Trechus Clairville is distributed mainly in the Holarctic regions, but 24 species from Ethiopia were described previously. A key to the species of Ethiopian Trechus is provided, including a new species, Trechus amharicus from the Choke Mountains (Ethiopian Highlands). The latter taxon is described. The species was found in the Afroalpine grassland, living under stones, sometimes located at the base of the giant Lobelia rhynchopetalum Hemsl. It is noteworthy that in spite of the small number of known species of Ethiopian Trechus, there are more morphological and chaetotaxic variations among them than in their Holarctic congeners. The taxonomic position of the new species is difÞcult to situate, because T.amharicus does not Þt in any of the groups of species recognized to date in Ethiopia. T.amharicus n. sp. bears some resemblance to T.patrizii in that it has a pronotum with posterior angles without setae, and elytra with only a single anterior discal seta. However, the different conÞguration of the protarsus and aedeagus in the male clearly separates the two taxa. KEY WORDS Carabidae, Trechus, Ethiopia, taxonomy The Trechini constitute a large tribe of Carabidae that has radiated into a diverse series of lineages and extended throughout a large part of the world. There is a remarkable degree of disparity within this tribe (sensu Gould 1989), the result of adaptation to various types of edaphic life styles that has even led to the development of an “aphaenops-like facies.”Nevertheless, the “phyletic lineage of the Trechus”(sensu Casale and Laneyrie 1982) is above all interesting for its great speciÞc diversity, because it includes the enormous genus Trechus Clairville, 1806. This taxon contains ⬎600 species, most of which are Palaearctic in distribution (Moravec et al. 2003). However, in the Nearctic region only around Þfty species are known to exist (Larochelle and Larivie`re 2003), whereas just a few Trechus live outside the Holarctic region in, e.g., eastern Africa (Casale et al. 1988). The Þrst records of Trechus in Ethiopia were made by Raffray (1885), who described two species, to which Alluaud (1918) subsequently added a third. These three Ethiopian species are the only species to be mentioned by Jeannel (1927), whose comprehensive work contains much of our current knowledge of this genus. This monograph, nevertheless, is insufÞcient as an up-to-date tool for the study of the situation of this genus in Ethiopia. More recent publications (Jeannel 1935, 1950, 1954, 1960; Pawlowski 2001, Magrini and Sciaky 2006) have broadened our knowledge of the Trechus, and today ⬎25 species are known from this region of Africa. The objectives of this study was to 1) provide a key to the Trechus species of Ethiopia, including a new species from the Choke Mountains; and 2) to describe the latter, the fourth known from that zone in central Ethiopia, but very different from the species belonging to the Trechus chokensis-group (sensu Pawlowski 2001). Materials and Methods Specimens of the new Trechus were collected during an entomological expedition in the Choke Mountains (Ethiopian Highlands), lying north of Debre Markos (Gojam, Ethiopia). This expedition was supported Þnancially by the University of Santiago de Compostela (Spain). It was made possible by a Memorandum of Understanding between the Wildlife Conservation Department (Ethiopia) and the University of Santiago de Compostela, signed in Addis Ababa in 2005, concerning a project to prospect for species of Carabidae in several zones in the Ethiopian Highlands. The specimens were collected by turning over stones, and looking for them under mats of vegetation and leaf litter, by using a Winkler sieve and Mocsarsky apparatus. For an explanation of both devices, see Colas 1969). The aedeagus was extracted from the abdomen, and the parameres were separated from the surface of the median lobe, and immersed in lactic acid for maceration. After examination, the genital preparations were put in dimethyl-4 hydroxy-3(2H)-furanone (DMHF) on 1 Departamento de Zoologõ´a y Antropologõ´aFõ´sica, Facultad de Biologõ´a, Universidad de Alcala´, E-28871 Alcala´de Henares, Madrid, Spain. 2 Corresponding author: Departamento de Zoologõ´ay Antropologõ´a, Facultad de Biologõ´a, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, A Corun˜a, Spain (e-mail: [email protected]). 0013-8746/11/0132Ð0140$04.00/0 䉷2011 Entomological Society of America Downloaded from https://academic.oup.com/aesa/article/104/2/132/2758568 by Fac de Medicine Biblioteca user on 21 January 2021 an acetate sheet. To prepare the female reproductive appendages, the terminal abdominal segments were Þrst placed in a saturated solution of KOH and then washed in ScheerpeltzÕs solution (composition of the latter: 75% ethyl alcohol, 20% water, and 5% acetic acid. See Marcos Garcõ´a and Galante Patin˜o 2004) and opened dorsally. Staining was with Chlorazol black E in aqueous solution. After removing the excess dye with KOH, the structures were washed again with ScheerpeltzÕs solution, then prepared for observation and drawing. The female genital preparations were included in DMHF and put on an acetate sheet. We follow Puff and Nemomissa (2005) to describe some details referring to the type of vegetation. Results Description of Trechus amharicus Ortun˜o& Novoa, n. sp. (Figs. 1Ð3) Type Material. All specimens collected by F. Novoa (leg.). Holotype male. Ethiopia. Danghle, Mt. Choke, Debre Markos; 10⬚38⬘19.26⬙N, 37⬚50⬘04.15⬙E, 3,793-m altitude, 24-III-2005. Deposited in the Museo Nacional de Ciencias Naturales de Madrid, Madrid, Spain (type catalog no. 2103). Paratypes. Six males and four females with the same locality and data as the holotype; three males and two females collected in Waybein, Mt. Choke, Debre Markos; 10⬚34⬘56.41⬙N, 37⬚47⬘18.94⬙E, 3,264-m altitude, 23-III-2005, all deposited in the Departamento de Zoologõ´a y Antropologõ´a, Universidad de Santiago de Compostela, Spain (F. Novoa collection) and the Departamento de Zoologõ´a y Antropologõ´aFõ´sica, Universidad de Alcala´, Spain (V. M. Ortun˜o collection). Etymology. Dedicated to the Semitic language of Amharic in homage to this Ethiopian people. Diagnosis (Figs. 1, 2f, 3b and d). Apterous species; eyes large and prominent; integument shiny, glabrous except for small areas furnished with microtrichia (eyes and tempora). Color dark brown, appendages paler. Pronotum suborbicular, transverse, with hind angles obtuse but marked. Elytra oval-shaped, convex, shoulders not marked; six striae visible, the three inner ones well marked, one and two usually entire. Sometimes, a seventh stria is discernible. Male protarsi with only the Þrst segment moderately dilated. Aedeagus falciform, apical lamina wide and rounded, basal bulb Fig. 1. Habitus of T.amharicus Ortun˜o & Novoa n. sp. Scale bar ⫽1 mm. Fig. 2. Morphological details of T.amharicus Ortun˜o& Novoa n. sp. (a) Labium, prebasilar, and ligula (with labial palps). (b) Antenna. (c) Pronotal microsculpture. (d) Elytral microsculpture. (e) Left protibia and protarsus in the dorsal view. (f) Protarsum of the male. (g) Mesotarsus of the male. (h) Metatarsus of the male. (i) Protarsum of the female. (j) Last abdominal sternum of the male. (k) Idem of the female. Scale bars (a, b, e, f, g, h, i) ⫽0.2 mm, 0.05 mm (c and d), and 0.3 mm (j and k). March 2011 ORTUN ˜O AND NOVOA:TRECHUS FROM ETHIOPIAN HIGHLANDS 133 Downloaded from https://academic.oup.com/aesa/article/104/2/132/2758568 by Fac de Medicine Biblioteca user on 21 January 2021 without sagittal winglet, and scaly internal sac with two fore areas scleroticized. Description. Length (from tip of mandible to apex of elytra): 3.2Ð3.5 mm. Head (Fig. 1) nearly as long as wide (not considering mandibles in length); labium emarginate with a tooth monodentate (Fig. 2a); frontal furrows deep, prolonged to clypeus, outlining supraocular and ocular areas; eyes large and prominent, producing a large ocular convexity, prolonged over the area of the temples, the latter reduced; ocular surface and temples furnished with microtrichia. Antennae Þliform (Figs. 1 and 2b), pilose and long, reaching the basal third of the elytra. Antennomeres (Fig. 2b) with a length (L)-to-width (W) ratio of ⬇2.25, with the exception of: antennomere 1 (ratio L/W ⬇1.8); antennomere 3 (ratio L/W ⬇2.6); antennomere 10 (ratio L/W ⬇2.0); antennomere 11 (ratio L/W ⬇2.9). Cephalic chaetotaxy (Fig. 1): one seta in the sulcus of each mandible; two setae on the labial disc, and six setae on the prebasilar area; six setae on the labrum; two setae at both sides of the clypeus; two pairs of supraocular setae, anterior and posterior, the former located at the level of the middle of the inner margin of the eye, the latter posteriorly to it. Pronotum (Fig. 1) suborbicular, transverse (ratio L/W ⫽0.7), widest at the apical third; disc convex, divided lengthways by a fairly marked medial sulcus; basal margin produced a little forward at the middle, clearly oblique inside the hind angles; sides rounded in their anterior part, straight posteriorly, with short sinuation before the hind angles; the latter obtuse but marked; lateral depressions narrow and deep. Basal foveae shallow, weakly impressed, not punctate. Disc with isodiametric microsculpture of the integument (Fig. 2c). Pronotal chaetotaxy (Fig. 1): only one seta on each side, located on the Þrst third; a minute pore next to the hind angles. Elytra (Fig. 1) with curved sides, oval-shaped, its greatest width at the middle; shoulders not marked; basal margin short, slightly oblique; border rounding the shoulder reaching the level of the fourth stria; striae slightly punctate; six striae visible (sometimes, a seventh stria is discernible), the three inner stria well marked, one and two usually entire; scutellary striole distinct; a deep recurrent striole conspicuous at the apex; intervals 1, 2, and 3 more or less convex, the rest ßat; lateral channel wide. Disc with isodiametric microsculpture more transverse (Figs. 2d). Elytral chaetotaxy (Fig. 1): scutellar pore at the origin of the Þrst stria; one setigerous puncture near the end of the second stria; one discal seta on the third stria, located in the anterior fourth; marginal umbilical series as follows: humeral area with four equidistant setae, and subapical area with four setae, two anterior and two posterior. Legs (Figs. 1 and 2eÐi) have femora and tibiae without special characteristics; anterior tibiae with scarce pilosity on distal dorsum and without longitudinal sulcus; two clip setae on the cleaner organ of the protibiae (Fig. 2e); all tarsi with basitarsi as long as the sum of the two following basitarsi; male protarsi with only the Þrst segment moderately dilated (ratio L/W ⫽2) (Fig. 2f), provided with a tooth on the internal margin and adhesive setae ventrally. Last sternite of abdomen with two short setae in males (Fig. 2j) and four in females (Fig. 2k). Ring of the male genital segment pyriform (Fig. 3a). Aedeagus with medial lobe symmetrical in dorsal view (Fig. 3d), falciform in lateral view (Fig. 3b), regularly arched, but with a slender preapical swelling; apical lamina wide and rounded; basal bulb without sagittal winglet; scaly internal sack without laminar copulatrix pieces (Fig. 2b and d), with two areas exhibiting very scleroticized scales on each side of the sagittal plane (Fig. 3d). Parameres subsymmetrical (the right slightly shorter), laminates and plurisetules normally with four setae (Fig. 3c and d). Female genitalia. External genitalia (Fig. 3e and f) formed by dimerous IX gonopods (gonocoxites and subgonocoxites) and IX laterotergites; gonocoxite unguiform with an ensiform seta on the ventral surface (sometimes lacking in some specimens) and two ensiform setae (of uneven size) on the dorsal surface close to the internal edge; near to the apex, a nematiform seta is located on a little ogival fovea; the subgonocoxite is longer than wide, provided with a dozen thorn-shaped setae, of different length and size, located close to the internal edge, most on the ventral surface, some on the dorsal Fig. 3. Morphological details of T.amharicus Ortun˜o& Novoa n. sp. (a) Ring of male genital segment. (b) Median lobe in left lateral view. (c) Left and right parameres in lateral view. (d) Median lobe in dorsal view. (e) External female genitalia. (f) Female genitalia (including spermathecal complex). Scale bars (aÐd) ⫽0.3 mm, 0.1 mm (e) and 0.2 mm (f). 134 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 104, no. 2 Downloaded from https://academic.oup.com/aesa/article/104/2/132/2758568 by Fac de Medicine Biblioteca user on 21 January 2021 face; aliform IX lateritergite is weakly scleroticized, with one group of 15 setae assembled like a fringe over the basal margin and another one consisting of six setae scattered on the ventral surface. Spermathecal complex (internal genitalia) (Fig. 3f) is completely membranous, spermathecal and accessory glands wanting; tube-shaped vagina-bursa with longitudinal folds; its proximal end widens, making contact with the oviduct. Sexual Dimorphism. Male: protarsi with only the Þrst segment dilated and provided with adhesive setae (Fig. 2f and i); last abdominal sternite, with two setigerous pores close to the apical margin (Fig. 2j). Female: last abdominal sternite provided with four setae near apical margin (Fig. 2k). Distribution. The species is only known from two localities in the Choke Mountains, Danghle and Waybein, northwest of Debre Markos, as we indicated in the type material. Ecology. The species was found in the Afroalpine grassland, as in Danghle (nearly 3,800-m altitude), where the only tree-like plants were the Giant Lobelias, Lobelia rhynchopetalum Hemsl, forming large populations often consisting of hundreds of individuals, as in the Simen Mountains (Puff and Nemomissa 2005). The species was living under stones, sometimes located at the base of lobelias. In Waybein (⬇3,200-m altitude) the new Trechus was in a degradated ericaceous forest, living under stones and depressed mats of vegetation. Key to Ethiopian Trechus Species 1. Elytra with one discal seta ...........(2) Elytra with two discal setae ..........(5) 2. Elytra retaining a hind discal seta (close to the fourth stria); striae very faint. Aedeagus with median lobe falciform and small sagittal winglet (Fig. 4a); internal sac without copulatrix pieces. Length ⬇2.5 mm. Distribution: Arguine, Simen ......T.ambarasensis Jeannel, 1954 Elytra retaining fore discal seta (on third stria) .......................(3) 3. Pronotum with hind angles rectangular; two setae on each side of the pronotum (fore and hind). Elytra with striae 1Ð4 deep, the rest superÞcial. Aedeagus: with median lobe as a reßexed hook at apex and basal bulb with a small sagittal winglet (Fig. 4b); internal sac scaly and with a large copulatrix piece. Length ⬇5.5 mm. Distribution: Petit Akaki (tributary river from Awash River) ...... ............ T.aethiopicus Alluaud, 1918 Pronotum with hind angles obtuse and no hind seta on either side. Elytra with striae 1Ð3 well developed, the others obsolete or only weakly marked ......................(4) 4. Male protarsus with Þrst two tarsomeres dilated. Base of pronotum protruded. Aedeagus with median lobe almost straight, with a reßexed hook at apex, and basal bulb with a sagittal winglet (Fig. 4c); internal sac with a small copulatrix piece weakly scleroticized. Length ⬇3.6 mm. Distribution: Torre Asciaba and Aselle (Mt. Chilla´lo) .....T.patrizzi Jeannel, 1960 Male protarsus with only the Þrst tarsomere dilated (Fig. 2f). Base of pronotum slightly notched. (Fig. 1). Aedeagus with medial lobe falciform; apex not distinctive (rounded lamina); basal bulb without sagittal winglet; scaly internal sac (no laminar copulatrix pieces), with two fore areas (one on each side of the sagittal plane) with very scleroticized scales (Fig. 3b and d). Length: 3.2Ð3.5 mm. Distribution: Debre Markos (Mt. Choke) ..... .................. T.amharicus n. sp. 5. Integument with microtrichia, at least on elytra (in some species, it is more distinct in one sex than the other, or found on the apical third of the elytra) ....................(6) Elytra glabrous .................(10) 6. Pronotum transverse (arcuate sides) or cordate (sides slightly sinuate), but in both cases with hind angles well marked. Elytra with all striae very visible and discal setae arranged on the third stria. Aedeagus with sagittal winglet; internal sac with copulatrix pieces scleroticized. Medium to large species (length: 4.5Ð7.0 mm) ..........(7) Pronotum with arcuate sides and rounded hind angles; at least the second discal seta posiFig. 4. Morphology of the median lobe (aedeagus) of other Ethiopian Trechus species: (a) T.ambasarensis. (b) T. aethiopicus. (c) T.patrizzi. (d) T.chokensis. (e) T.dimorphicus. (f) T.gigas. (g) T.martelluccii. (h) T.raffrayanus. (i) T.peynei. (j) T.bastianinii. (k) T.simienensis. (l) T.loeffleri. (m) T.gugheensis. (n) T.gallorites. (o) T.scotti. (p) T.chillalicus. (q) T.bipartitus. (r) T.culminicola. (s) T.batuensis. (t) T. buhaitensis. (u) T.schimperanus. Redrawn from Jeannel 1927, 1935, 1950, 1954, 1960; Pawlowski 2001, and Magrini and Sciaky 2006. March 2011 ORTUN ˜O AND NOVOA:TRECHUS FROM ETHIOPIAN HIGHLANDS 135 Downloaded from https://academic.oup.com/aesa/article/104/2/132/2758568 by Fac de Medicine Biblioteca user on 21 January 2021 tioned close to the fourth stria or about where the stria would be if it were impressed........................... (9) 7. Length: 4.5Ð5.5 mm. Slight sexual dimorphism (observable by females somewhat larger than males). Elytra with striae distinctly punctate and ßat intervals. Aedeagus arcuate with a slightly raised apex (Fig. 4d); internal sac with a narrow oblong copulatrix piece, well scleroticized; parameres with four setae. Distribution: Mt. Choke ....T.chokensis Pawlowski, 2001 Length ⱖ5.9 mm. Marked sexual dimorphism, observable on the surface of the elytra. Aedeagus with distinct raised apex; internal sac with two long copulatrix pieces .......(8) 8. Males with elytral striae distinctly punctate and smooth intervals; striae in females impunctate striae, but intervals strongly punctate. Aedeagus: voluminous basal bulb and apex resembling a raised hook (Fig. 4e). Length: 5.9Ð6.7 mm. Distribution: Mt. Choke .......... ......... T.dimorphicus Pawlowski, 2001 Elytral striae distinctly punctate in both sexes; smooth intervals in males but strongly punctate in females. Pronotum with microtrichia, especially in females. Aedeagus especially robust at the level of the internal sac, and the apex regularly curved upward to resemble a hook (Fig. 4f); parameres with six setae. Length: 6.2Ð7.0 mm. Distribution: Mt. Choke. .............. T.gigas Pawlowski, 2001 9. Elytra with no traces of striae; discal setae (fore and hind) situated at about where the fourth stria would be. Small species (length: 2.5Ð2.6 mm). Distribution: Mindigabsa (Simien). . . .T.pilosipennis Jeannel, 1954 [male unknown] (Pawlowski (2003) indicates the possibility that females described as T.pilosipennis Jeannel 1954 corresponds to the males described as T.buahitensis Jeannel 1954) Elytra with Þve Þrst stria visible but poorly marked; fore discal seta on the third stria and the hind seta contiguous with the fourth stria. Aedeagus robust (Fig. 4g) with sinuous basal lamina; basal bulb voluminous with no sagittal winglet; apex slightly raised; internal sac consisting of two diverging lines of large scleroticized spines. Medium-sized species (length ⬇3.4 mm). Distribution: Inatye (Simien) . . . ...... T.martelluccii Magrini & Sciaky, 2006 10. Umbilical series peculiar, more numerous than (4⫹4) .....................(11) Umbilical series normal (4⫹4) ......(12) 11. Umbilical series (4⫹2⫹4). Elytra with all striae visible. Aedeagus with basal lamina subrectilinear (Fig. 4h); parameres with three diverging setae. Length: 4.5Ð5.0 mm. Distribution: Maõ¨Datcha (east of Arcuasie´)..... ........... T.raffrayanus Jeannel, 1954 Umbilical series with greater number of setiferous pores, variable in both number and arrangement (4⫹1⫹6/6⫹1⫹6/5⫹1⫹4⫹2, etc.). Elytra with all striae visible and heavily marked. Aedeagus with basal lamina slightly gibbose (Fig. 4i); parameres with four setae. Length: 4.7Ð5.0 mm. Distribution: Inatye (Simien) .....T.peynei Magrini & Sciaky, 2006 12. Pronotum with hind angles rectangular . . . (13) Pronotum with hind angles obtuse, rounded, or without noticeable angles (orbicular pronotum) ......................(15) 13. Pronotum transverse with sides slightly sinuate in front of the hind angles, the latter sharp and slight diverging. Elytra with six striae visible, which fade out from the third striae outward; intervals ßat. Aedeagus rectilinear (Fig. 4j): with basal bulb almost in line with the median lobe with a large sagittal winglet; apex slightly raised; internal sac without copulatrix pieces; parameres with four setae. Length: 4.6Ð5.0 mm. Distribution: Mt. Batu. ..... T.bastianinii Magrini & Sciaky, 2006 Pronotum cordate with evident sinuate sides. Elytra with all striae visible. Aedeagus noticeably incurved, with the apex tapering but not raised. Small size (length: 3.0Ð3.5 mm). . . (14) 14. Internal striae well marked; external striae more superÞcial but visible. Aedeagus thick, strongly incurved and with a large basal bulb without a sagittal winglet (Fig. 4k); internal sac without copulatrix piece; parameres short, with three setae. Length ⬇3.5 mm. Distribution: Maõ¨Datcha (east from Arcuasie´).......T.simienensis Jeannel, 1954 All striae well marked and visible almost to the apex of the elytra. Aedeagus falciform, with a small basal bulb provided with a sagittal winglet (Fig. 4l); internal sac with straight copulatrix piece; parameres with four setae. Length ⬇3.0 mm. Distribution: Inatye (Simien) ................. ....... T.loeffleri Magrini & Sciaky, 2006 15. Pronotum with hind angles marked and obtuse (sharp or blunt) ...............(16) Pronotum with hind angles either obsolete (more or less rounded) or without hind angles (pronotum suborbicular) ......(19) 16. Elytra with at most three striae visible . . . (17) Elytra with at least Þve striae visible (albeit superÞcial) ..................(18) 17. Elytra wide and short, almost orbicular, producing an Ocys harpaloides-like facies. Elytra with three striae visible (Þrst and second superÞcial, and third difÞcult to see). Pronotum clearly transverse, with regularly arcuate sides. Males larger than females. Aedeagus bent at right angles close to the basal bulb, the latter with a sagittal winglet and the apex thin, slightly raised (Fig. 4m); internal sac with a long hyaline copulatrix piece, covered with sclerotized scales; parameres with Þve setae. Length: 3Ð4 mm. Distribution: Mt. Tola ........T.gugheensis Jeannel, 1950 136 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 104, no. 2 Downloaded from https://academic.oup.com/aesa/article/104/2/132/2758568 by Fac de Medicine Biblioteca user on 21 January 2021 Elytra ovate, proportionally narrower, producing the facies of Trechus. Elytra with only Þrst stria obvious, second and third practically obsolete. Pronotum transverse with sides slightly arcuate. Males and females of similar size. Aedeagus straight: basal bulb without sagittal winglet, and the apex slightly raised, resembling a small hook (Fig. 4n); internal sac with a copulatrix piece; parameres with three setae. Length: 3.8Ð4 mm. Distribution: Mt. Chilla´lo......... .............T.gallorites Jeannel, 1936 18. Pronotum slightly transverse, with sharp hind angles (jutting somewhat outward). Elytra with shoulders; striae very superÞcial, but visible and without clear punctures. Aedeagus voluminous, slightly arcuate; basal bulb with a sagittal winglet; aberrant apex, broadened to resemble a chalice (Fig. 4o); internal sac hyaline without copulatrix piece; parameres with three setae. Length ⬇4.3 mm. Distribution: Mt. Chilla´lo......... ............... T.scotti Jeannel, 1936 Pronotum somewhat transverse, but with rounded hind angles. Elytra ovate with rounded shoulders; the Þrst Þve or six striae are faint and superÞcial, but still visible; the most external striae are totally obsolete. Aedeagus short, thick, and only slightly arcuate; basal lamina lightly gibbose; basal bulb with a small sagittal winglet; apex in a small hook (Fig. 4p); internal sac with a long copulatrix piece; parameres with four setae. Length ⬇6.5 mm. Distribution: Mt. Chilla´lo..... ............ T.chillalicus Jeannel, 1936 19. Pronotum suborbicular without hind angles; hind margin is considerably narrower than fore margin. Elytra ovate, short, with all striae visible (albeit Þne and superÞcial). Aedeagus: long and strongly bent; basal bulb with a sagittal winglet; apex thin, slightly raised, with a small subterminal and ventral notch (Fig. 4q); internal sac with a long and undulating copulatrix piece. Length ⬇4.0 mm. Distribution: Abuna Yusef MaleÞa . . . ............ T.bipartitus Raffray, 1885 Pronotum more or less transverse or quadrate, with rounded hind angles (obsolete) . . . (20) 20. Elytra with discal setae on third stria . . . (21) Elytra with discal setae contiguous with fourth stria .......................(22) 21. Elytra with Þne and superÞcial striae, the Þrst three very visible. Aedeagus long, slightly arcuate, but strongly ßattened dorsoventrally; basal bulb a little bent and with a sagittal winglet (Fig. 4r); internal sac without copulatrix pieces; parameres short with three setae. Length: 2.8Ð3 mm. Distribution: Mt. Chilla´lo......T.culminicola Jeannel, 1936 Elytra with Þve striae visible but becoming progressively fainter. Aedeagus robust, slightly curved except at the basal bulb, which is large with a small sagittal winglet; apex reinforced ventrally by an apical button (Fig. 4s); internal sac with a triangular copulatrix piece with a spatulate apical process; parameres short with four setae. Length: 3.4Ð3.9 mm. Distribution: Bluff Tarn and Big Lake (Mt. Batu) . . . T.batuensis Magrini & Sciaky, 2006 22. Elytra short (approximately one fourth longer than wide) with superÞcial striae, including the disc. Small size (length ⬇2.5 mm). Distribution: Abuna Yusef MaleÞa ........ ...... T.sublaevis Raffray, 1885 [aedeagus unknown] Elytra longer (nearly one-thirds longer than wide) ......................(23) 23. Integument with regular microsculpture forming an isodiametric network. Elytra with subparallel sides. Distribution: Mecana Abbo (Simien) . . . T.degienensis Jeannel, 1954 [male unknown] Integument with regular microsculpture forming a transverse network. Elytra more or less ovate ......................(24) 24. Pronotum with more rounded sides. Elytra with shoulders somewhat prominent. Aedeagus: thick and straight; short basal bulb, sharply bent and with no sagittal winglet; basal lamina gibbose; apex retracted into the quadrate lamina (Fig. 4t); internal sac without copulatrix pieces; sclerotized fork-like ligule on the dorsal surface of the median lobule (Fig. 4t); slender parameres with three setae. Length: 3.0Ð3.2 mm. Distribution: Lori (Simien) and Maõ¨Datcha (east of Arcuasie´).....T.buahitensis Jeannel, 1954 Pronotum with less rounded sides. Elytra with shoulders only weakly marked. Aedeagus: slender and sinuate; basal bulb without a sagittal winglet; apex long and compressed laterally in a blade-like manner (Fig. 4u); internal sac without copulatrix pieces; parameres with four setae. Length: 2.8Ð3.0 mm. Distribution: Aostagheb and Mindigabsa (Simien) ....T.schimperanus Jeannel, 1954 Discussion The presence of Trechus in the mountains of Ethiopia presumably represents a relict fauna of a group of that once had a more contiguous distribution. Today, the disjointed distribution of Trechus in Africa is a result of the implantation and extension of a subSaharan-type climate (Jeannel 1927, Mani 1968), which has severely reduced the size of this boreal genusÕ optimum area for survival. This climatic process has also affected the current distribution of other animal and plant species in this part of Africa, and the distribution of carabid Calathus, essentially Holarctic but also present in Ethiopia, a case similar to that of Trechus (see Mani 1968). March 2011 ORTUN ˜O AND NOVOA:TRECHUS FROM ETHIOPIAN HIGHLANDS 137 Downloaded from https://academic.oup.com/aesa/article/104/2/132/2758568 by Fac de Medicine Biblioteca user on 21 January 2021 Trechus species are geophilous, hygrophilous, and sciophilous Carabidae that are found in the mountains of eastern Africa, where the environmental conditions enable them to thrive. Their adaptation to a hypsobiontic life style is evident from their micropterism and tendency toward melanism, characteristics that are present in all Ethiopian Trechus. Both of these traits are adaptive and are common in Coleoptera that live in high mountain areas (Mani 1968). Despite the relatively small number of species (twenty-four species currently described, plus T. amharicus n. sp.), there are more morphological and chetotaxic variations in the Ethiopian Trechus than in their Holarctic congeners. Thus, we Þnd in the Ethiopian Trechus the following exceptional characteristics: 1) variable pilosity on dorsum; 2) more umbilical setae than usual (4⫹4); 3) loss of one of the dorsal setae from the elytra; 4) displacement of one of the dorsal setae toward the fourth stria; 5) loss of the angular setae (posterior margin) from the pronotum; 6) a male protarsus with only a single dilated tarsomere; 7) sexual dimorphism in characteristics other than the protarsus; and 8) an aedeagus without copulatory pieces. A large number of these single characters are present in unrelated species and in somewhat modiÞed forms in some of the ⬎500 Holarctic species of Trechus. In Trechus the degree of pilosity on the head, pronotum, and elytra is variable, but is in general an infrequent character in this genus (Israelson and Palm 1979), known from a few Macronesian species such as Trechus fortunatus Jeannel, 1927; Trechus uyttenboogaarti Jeannel, 1936; Trechus cabrerai (Jeannel 1936); Trechus laureticola Jeannel, 1936; Trechus machadoensis Franz, 1984, and Trechus gomerensis Franz, 1986. This character is even less frequent in Western Palaearctic species (e.g., Trechus carrilloi Toribio & Rodrõ´guez, 1997), but is, nevertheless, well represented in Þve of the 25 known Ethiopian species (see dichotomous key). Most umbilical series in Trechus occur in two separate groups, a humeral group of four setae and a preapical group of four setae. This character has been well described by Jeannel (1927, 1941). Nevertheless, some Ethiopian species have more setae in the umbilical series, and setae appear in the gap between the humeral and preapical groups, the umbilical series thereby appearing irregular and ungrouped. This is very rare within this genus and is present in at least two of the 25 Ethiopian species (see dichotomous key). It is possible that if he had known these Trechus species, Jeannel (1927) would not have used the “regular or irregular nature of the umbilical series”as the Þrst and only step in his key to the genera of Trechini with glabrous fore-tibiae (Jeannel 1927, p. 113). The discal setae also differ from the generalized and almost universal model used to separate the two subgenera of Trechus: two discal setae in Trechus and three in Epaphius Stephens, 1827. In this case, Jeannel (1927, 1941) indicates the possibility that the species of the subgenus Trechus only have a single discal seta, as exempliÞed by Trechus aethiopicus Alluaud, 1918, which posseses this trait. Subsequently Jeannel described two other Ethiopian species that also share this characteristic (Jeannel 1954, 1960). With the description of T. amharicus n. sp., four of the 25 species of Trechus have just one discal seta. Nevertheless, of these species, three conserve the anterior discal setae, whereas only one, Trechus ambarasensis Jeannel, 1954, a posterior seta. The presence of a single dorsal seta is not the only difference in setation seen in some Ethiopian species: whereas in most Trechus the discal setae are found on the third stria, in a small number of Ethiopian species the setae are displaced toward the fourth interval and are in contiguous with the fourth stria. The rarity of this feature in Trechus was highlighted by Raffray (1885) in his description of Trechus sublaevis. Subsequently, Jeannel (1954) described this character in Þve other species and proposed the T. sublaevis group. Recently, T. martelluccii Magrini & Sciaky, 2006 has been described, which should also be included in this group, thereby raising the total of known species that have all or some of the discal setae displaced toward the fourth stria to six out of twentyÞve. The angular seta (posterior margin) on the pronotum, usually present in Trechus, is not present in either Trechus patrizzi Jeannel, 1960, or T. amharicus n. sp. Sexual dimorphism in Trechus species is not very evident and normally consists of the dilation of the Þrst two tarsomeres of the male protarsus, which is not seen in females. Somewhat more infrequently, sexual dimorphism is indicated by size: in Trechus jeannei Sciaky, 1998, males (length: 5, 4Ð6, 1 mm) are longer than females (length: 4, 8-5, 2 mm). Rarer still are cases in which dimorphism appears in other parts of the body: e.g., a curved tibia in males (e.g., Trechus jeannei Sciaky, 1998), signiÞcant differences in the type of microsculpture on the tegument, presence of elytral micropunctures in the males, but absent in the females (e.g., in the Ethiopian species, Trechus dimorphicus Pawlowski, 2001, or differences in the nature of the pubescence on the tegument, as well as its absence or presence. Pawlowski (2003) notes the presence of this latter character in the T. chokensis group, which this author refers to as the T. buahitensis group, separated from the T. sublaevis group of Jeannel (1954). Nevertheless, consistent sexual dimorphism does exist in some Ethiopian Trechus species, and there are in fact a few species whose teguments vary in appearance according to sex. This leads to the suspicion that some of the species for only the female form has been described (see dichotomous key) could in fact correspond to dimorphic species whose males have been ascribed a different scientiÞc name. In this regard, Pawlowski (2003) suggests that female Trechus pilosipennis Jeannel, 1954, may actually be Trechus buahitensis Jeannel, 1954. A surprising degree of sexual dimorphism occurs in the Ethiopian species in which, e.g., some males only have a single dilated articulation on the protarsus. Even though this characteristic is present in the Nearctic subgenus Microtrechus Jeannel, 1927, Pawlowski (2003) notes its presence in a number of still undescribed species for which he in138 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 104, no. 2 Downloaded from https://academic.oup.com/aesa/article/104/2/132/2758568 by Fac de Medicine Biblioteca user on 21 January 2021 dicates the possibility of designating a new subgenus; T. amharicus n. sp. should be included in this new group of species. In our opinion, the rarity of this morphological trait Ð like the pilosity on the tegument or the absence or displacement of the discal setae Ð should not complicate the taxonomy of the genus Trechus. On the contrary, instead of creating new subgenera, it would seem more reasonable to redeÞne the genus Trechus in light of current knowledge. Likewise, this is perhaps also an opportunity to reexamine some of the morphological characteristics used by Jeannel (1927) to separate groups of species, as well as genera and subgenera. It is thus possible that the description of Microtrechus is erroneous when proposed as a genus and used as such (Jeannel 1927, Ball and Bousquet 2001). It has been used subsequently and referred as a subgenus of Trechus (Ball and Bousquet 2001, Larochelle and Larivie`re 2003, Pawlowski 2003). It is probable that Microtrechus represents a lineage within Trechus but should not be used as a subgenus, given that its existence is based primarily on the difference in the male protarsus. This character also appears in another group of Trechus from Ethiopia, to which can be added a species from Madeira, Trechus (Atlantotrechus)cautus Wollaston, 1854, which Lompe (1999) has separated from its congeners into a new subgenus, Atlantotrechus Lompe, 1999. Thus, given that the apomorphy of a single dilated tarsomere in males appears sporadically in Trechus belonging to different lineages (America, Madeira archipelago, and eastern Africa) and is not a characteristic that distinguishes just one group within the Trechus, it perhaps would be wise to consider both Microtrechus and Atlantotrechus Lompe, 1999 as synonymous with Trechus. Finally, in some Ethiopian Trechus the internal sac of the aedeagus has no copulatory pieces, and instead there is a hyaline sac covered in scales or spines. Although this is not a novelty in the genus as a whole, this character appears more frequently in the Ethiopian species (in 10 of 22 species for whom males are known; see dichotomous key) than in those from other areas of the Northern Hemisphere. In a discussion of the taxonomic position of T. amharicus n. sp., it is difÞcult to situate this species in any of the species groups recognized to date in Ethiopia. We believe that taxonomic and faunal knowledge of the Ethiopian Trechus is still too incomplete to analyze the diversity of the members of this genus in great depth or to examine the combinations of characteristics that appear within these species. Pawlowski (2001) has described Þve groupsÑthe T. aethiopicus group, T. simienensis group, T. bipartitus group, T. sublaevis group, and T. chokensis groupÑand further notes (Pawlowski 2003) that three as yet unpublished groups should be added to these Þve, which he names the ␣ -group, ␤ -group, and ␥ -group. Although this author provides a series of characteristics for these unpublished groups, the information provided is in fact rather confusing. Despite this effort to solve the systematics of the Ethiopian Trechus group, there are still species that do not Þt into any group, as Magrini and Sciaky (2006) recognize in the case of T. bastianinii. This also occurs with T. amharicus n. sp., which possesses diagnostic characteristics from each of a number of different groups. Thus, it would seem that there is a real need to examine the validity of the systematics of the Ethiopian Trechus as proposed by Pawlowski. T. amharicus n. sp. bears a close resemblance to T. patrizii, although this does not necessarily mean that any close phylogenetic relationship exists between them. Both species have a series of apomorphies that are truly singular within the context of this genus: pronotum with posterior angles without setae and elytra with only a single anterior discal seta. Moreover, they also have in common other less obvious characteristics such as obtuse posterior angles on the pronotum, and elytra with only the Þrst three striations visible. Nevertheless, certain differences between these two species leave no doubt as to their separation into two distinct species: T. amharicus n. sp. differs from T. patrizii in its very different medial lobe and the internal sac of the aedeagus. They are also clearly different in the conÞguration of the male protarsus: in T. amharicus n. sp. the Þrst tarsomere is somewhat dilated, whereas in T. patrizzi the Þrst and second tarsomeres are both dilated, as in the majority of Trechus species. In conclusion, we believe that before proposing new taxonomic groups it would be best to have at our disposal information regarding all Ethiopian species to be able to place future discoveries in their correct places within this genus. Acknowledgments We thank Tadesee Hailu (Wildlife Conservation Department, Ministry of Agriculture, Ethiopia) and the Bureau of Agricultural and Rural Development of Amhara Region for permission to sample carabid beetles in the Choke Mountains. We also thank Prof. Gil Sa´nchez (ETSIM, Polite´cnica de Madrid) and Juan Novoa and Dr. Ramo´n Novoa for Þeldwork in the Mount Choke expedition. We are grateful to Kebede Samson for extraordinary assistance as a guide and to Dr. Tadesee Wubalem for introducing us to the Ethiopian Wildlife Conservation Organization. This work was supported by the University of Santiago de Compostela (Spain), and we are especially grateful to Eduardo Garcõ´a-Rodeja. This research has also been partially Þnanced by the I3 program of Incentivation of the Incorporation and IntensiÞcation on Research Activity of the Ministry of Education and Science of Spain, of which V.M.O. is the beneÞciary. References Cited Alluaud, C. 1918. Collections recuillies par M. Maurice de Rothschild dans lÕAfrique orientale. Cole´opte`res Carabiques; diagnoses pre´liminaires des espe`ces nouvelles. Bull. Mus. Hist. Nat. Paris 24: 493Ð497. Ball, G. E., and Y. Bousquet. 2001. Carabidae, pp. 22Ð132. In R. H. Arnett, Jr., and M. C. 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