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

Trechosiella scotti swartbergensis subspec. nov.

Figs. 5 A–C, 9

Type material. [ SOUTH AFRICA, Western Cape Province]: HT ♂, labelled ‘S.Africa, Cape, Swartb[er]g., Meiringspoort. cent[ral]., shorewashing, 33.25S / 22.33E, 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. 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 5th and 7th elytral striae. Setiferous punctures of third stria inserted at anterior 1/5 and at middle of 3rd stria, respectively. Microsculpture of elytra weakly transverse, length/width ratio of mesh approximately 1:1 to 1:2 ( Fig. 5 C). Brachypterous. Aedeagus length (in dorsal view) 0.64 mm (n = 2) ( Fig. 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. 6 A–C, 9

Type material. [ LESOTHO]: HT ♂, labelled ‘S. Africa, Lesotho, Drakensb[er]g., Black M[oun]t[ain]., 29.31S 29.12E, 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. 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 1st elytral stria. Striae 2–4 effaced, yet still discernible, striae 5–7 totally effaced, indiscernible, 8th stria strongly impressed; recurrent sutural stria totally effaced on apex. Setiferous punctures of third stria inserted at anterior 1/4 and behind middle of 3rd stria, respectively. Microsculpture of elytra very fine, transverse, with length/width ratio of mesh approximately 1:5 to 1:10 ( Fig. 6 C). Apterous. Length of aedeagus in dorsal view 0.75 mm (n = 1) ( Fig. 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 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. 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. 8 A); anterior margin bearing two long central setae and 2 shorter lateral setae on each side, 3rd 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; 8th stria strongly impressed, 3rd and 4th 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 5th, 6th and 7th striae. A single (sometimes duplicated) setiferous puncture inserted at anterior 1/4 of 3rd stria. Microsculpture of elytra coarse, length/width ratio of mesh approximately 1:2 to 1:3 ( Fig. 7 C). Brachypterous. Aedeagus with average length (in dorsal view) 0.75 mm (n = 3) ( Fig. 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 3rd and 4th striae in the anterior quarter of the disc; and by the absence of the posterior setiferous puncture of the 3rd 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.

Figures

FIGURE 5. Trechosiella scotti swartbergensis subspec. nov., HT ♂ from Swartberg, Western Cape Province. General habitus (A), aedeagus (lateral view) (B), microsculpture of elytra between the anterior and posterior discal setiferous punctures (C).

FIGURE 6. Trechosiella oligophthalma spec. nov., HT ♂ from Black Mt., Lesotho. General habitus (A), aedeagus (lateral view) (B), microsculpture of elytra between the anterior and posterior discal setiferous punctures (C).

FIGURE 7. Trechosiella endroedyyoungai spec. nov., HT ♂ from Vanrhyn's Pass, Western Cape Province. General habitus (A), aedeagus (lateral view) (B), microsculpture of elytra between the anterior and posterior discal setiferous punctures (C).

FIGURE 8. Ligulae and labial palps (dorsal views) of T. endroedyyoungai spec. nov. (A), T. laetula (B), T. scotti s. str. (C), and T. katicola (D).