Trechosiella scotti swartbergensis , Geginat, Gernot, 2013

Geginat, Gernot, 2013, Taxonomic revision of the African genus Trechosiella Jeannel (Coleoptera: Carabidae: Trechinae), Zootaxa 3716 (3), pp. 441-459: 452-457

publication ID

http://dx.doi.org/10.11646/zootaxa.3716.3.7

publication LSID

lsid:zoobank.org:pub:D8B9E93B-2EC9-4DF8-B2F7-40F39AB0A65B

persistent identifier

http://treatment.plazi.org/id/038D87C5-FFC3-F61D-60D7-FAC730DA3BD8

treatment provided by

Plazi

scientific name

Trechosiella scotti swartbergensis
status

subspec. nov.

Trechosiella scotti swartbergensis  subspec. nov.

Figs. 5View FIGURE 5 A –C, 9

Type material. [ SOUTH AFRICA, Western Cape Province]: HT ♂, labelled ‘S.Africa, Cape, Swartb[er]g., Meiringspoort. cent[ral]., shorewashing, 33.25 S / 22.33 E, 1.11. 1993, E-Y: 2925, leg. Endrödy-Younga' (TMSA). PT 1 ♂ with the same locality data (GGC). The aedeagi of the HT and PT were examined.

Description. Body length 3.10–3.27 mm. Body and appendages light brown to yellow, legs lighter yellow ( Fig. 5View FIGURE 5 A). Eyes small, not protuberant; temple as long as diameter of eye; temporal lobe strongly developed, smooth. Frontal furrows and antennal length as in T. scotti scotti  . Ligula not examined. Pronotum cordiform, weakly transverse (length 0.68–0.70 mm, width 0.80–0.83 mm, average length/width ratio 0.85, n = 2); pronotal base, angles and impressions as in T. scotti scotti  . Shape of elytra similar to T. scotti scotti  ; elytral length 1.70–1.79 mm, width 1.17–1.20 mm, average length/width ratio 1.47, n = 2. Scutellar and elytral striae as in T. scotti scotti  . Intervals on elytral disc convex, not flattened. Recurrent sutural stria fairly strongly impressed on apex, confluent with the converging 5 th and 7 th elytral striae. Setiferous punctures of third stria inserted at anterior 1 / 5 and at middle of 3 rd stria, respectively. Microsculpture of elytra weakly transverse, length/width ratio of mesh approximately 1: 1 to 1: 2 ( Fig. 5View FIGURE 5 C). Brachypterous. Aedeagus length (in dorsal view) 0.64 mm (n = 2) ( Fig. 5View FIGURE 5 B); distal half of median lobe bulbous, very weakly bent ventrad, almost straight, apex blunt; internal sac with loop-like structure; styles broadly rounded, each bearing 5–7 long apical setae.

Differential diagnosis. Smaller and more lightly pigmented than T. scotti  s.str. and T. scotti macroptera  , with smaller and less protuberant eyes, and with the distal part of the median lobe of the aedeagus almost straight.

Remarks. Of this subspecies, only the two type specimens from the Swartberg are known. Trechosiella scotti swartbergensis  strongly resembles T. scotti scotti  , but shows some adaptations to endogeic life, such as depigmentation and some reduction of the eyes. Like many specimens of the other two subspecies, the specimens of T. scotti swartbergensis  were found by shorewashing.

Trechosiella oligophthalma  spec. nov. Figs. 6View FIGURE 6 A –C, 9

Type material. [ LESOTHO]: HT ♂, labelled ‘S. Africa, Lesotho, Drakensb[er]g., Black M[oun]t[ain]., 29.31 S 29.12 E, 9.3.1976; E-Y: 1060, from under stones, leg. Endrödy-Younga' (TMSA).

Description. Body shape and size as in T. laetula  ; body length 3.30 mm (n = 1). Color of body and appendages similar to that of T. laetula  , body yellowish brown, legs more yellowish ( Fig. 6View FIGURE 6 A). Eyes small, not protruding; temple twice as long as diameter of eye; temporal lobe well developed, smooth and without any wrinkles. Frontal furrows converging anteriad in basal half of frons, diverging thereafter towards anterior margin of clypeus, distinctly continued on clypeus towards anterior margin. Antenna reaching to between anterior and posterior setae on elytral disc. Anterior margin of labrum concave, almost triangular. Ligula not examined. Pronotum weakly cordiform, transverse (length 0.70 mm, width 0.90 mm, length/width ratio 0.78, n = 1), maximum width at the level of anterior 1 / 3, posterior angles rectangular, not protruding. Pronotal base laterally slightly slanted anteriad, basal impressions shallow, not divided into separate central and lateral impressions. Elytral length 1.90 mm, width 1.31 mm, length/width ratio 1.58 (n = 1), humeri rounded. Scutellar stria shallow, ending well before level of anterior setiferous puncture on elytral disc, continued by 1 st elytral stria. Striae 2–4 effaced, yet still discernible, striae 5–7 totally effaced, indiscernible, 8 th stria strongly impressed; recurrent sutural stria totally effaced on apex. Setiferous punctures of third stria inserted at anterior 1 / 4 and behind middle of 3 rd stria, respectively. Microsculpture of elytra very fine, transverse, with length/width ratio of mesh approximately 1: 5 to 1: 10 ( Fig. 6View FIGURE 6 C). Apterous. Length of aedeagus in dorsal view 0.75 mm (n = 1) ( Fig. 6View FIGURE 6 B). Median lobe long and straight, apex elongate, apex slightly bent ventrad, terminating in rounded tip; internal sac with triangular sclerotized internal piece; styles slightly tapered, each bearing 5 apical setae.

Differential diagnosis. Trechosiella oligophthalma  differs from all the other species of this genus by the strong reduction of its eyes, its depigmentation, the effaced elytral striae and the morphology of the aedeagus, having a long, straight median lobe and a single, triangular endophallic sclerite.

Remarks. An apterous species known from a single specimen discovered under a stone on Black Mountain in the Drakensberg Mountain Range. Trechosiella oligophthalma  shows advanced reduction of the eyes and a high degree of depigmentation, but the body and appendages have shapes similar to those in Trechosiella  species with fully developed eyes. Judging by the morphology of the aedeagus and the elytral microsculpture, T. oligophthtalma  is probably more closely related to T. laetula  and T. katicola  than to the other species of the genus.

Trechosiella endroedyyoungai  spec. nov. Figs 7View FIGURE 7 A –C, 8 A, 9

Type material. [ SOUTH AFRICA, Western Cape Province]: HT ♂, labelled ‘R.S.Africa, S. W. Cape, Vanrhyn’s Pass, from road gutter, 3123 ’S/ 1902 ’E, 4.11. 1983, E-Y: 2048, leg. Endrödy-Younga' (TMSA). PTs: 2 ♂, 7 ♂ with the same locality data (TMSA, GGC). The aedeagi of the HT and 2 PTs were examined.

Description. Size and shape similar to T. basilewskyi  , average body length 4.84 mm (n = 9). Body rufousbrown, legs lighter brown to yellow ( Fig. 7View FIGURE 7 A). Eyes not protruding, temples half as long as diameter of eyes; temporal lobe well developed, smooth. Frontal furrows as in T. laetula  . Antenna reaching anterior seta on elytral disc. Anterior margin of labrum very weakly concave. Ligula rectangular, apex flat, not rounded ( Fig. 8View FIGURE 8 A); anterior margin bearing two long central setae and 2 shorter lateral setae on each side, 3 rd lateral seta absent, possible vestigial insertion point present at middle of lateral margin of ligula. Pronotum weakly cordiform, transverse (average length 0.90 mm, average width 1.31 mm, average length/width ratio 0.69, n = 9), maximum width at level of anterior 1 / 3; posterior angles rectangular, not protruding; pronotal base straight, basal impressions shallow, not divided into separate central and lateral impressions. Average elytral length 2.87 mm, average width 1.87 mm, average length/width ratio 1.53 (n = 9), humeri well developed, rounded. Scutellar stria deeply impressed, ending before level of anterior setiferous puncture on elytral disc. Elytral striae 1–8 well discernible; 8 th stria strongly impressed, 3 rd and 4 th striae confluent in the anterior 1 / 4 of elytral disc, anterior of anterior setiferous puncture; recurrent sutural stria weak on apex, confluent with the converging 5 th, 6 th and 7 th striae. A single (sometimes duplicated) setiferous puncture inserted at anterior 1 / 4 of 3 rd stria. Microsculpture of elytra coarse, length/width ratio of mesh approximately 1: 2 to 1: 3 ( Fig. 7View FIGURE 7 C). Brachypterous. Aedeagus with average length (in dorsal view) 0.75 mm (n = 3) ( Fig. 7View FIGURE 7 B). Median lobe slightly curved ventrad, apex tapered; internal sac without prominent sclerotized internal armature; styles tapered, each bearing 2 long apical setae.

Differential diagnosis. T. endroedyyoungai  is different from all other Trechosiella  species by the striation of the elytral disc, characterized by the confluence of the 3 rd and 4 th striae in the anterior quarter of the disc; and by the absence of the posterior setiferous puncture of the 3 rd stria. The species is also characterized by an almost rectangular ligula and by the tapered styles of the aedeagus, each bearing only two long apical setae.

Remarks. T. endroedyyoungai  is a brachypterous species known from only the type series, discovered by the late Dr. Endrödy-Younga in Vanrhyn’s Pass on the border of the Western and Northern Cape Provinces. The presence of a flightless Trechosiella  in this semi-arid area is unexpected as all other known Trechosiella  species are humicolous or ripicolous. Considering the unique morphologies of the ligula and the aedeagus, this species seems quite isolated in the genus.