Thaumastella namaquensis Schaefer & Wilcox, 1971

Kment, Petr, Jacobs, Dawid H., Carapezza, Attilio, Deckert, Jürgen, Rider, David A. & Kóbor, Péter, 2024, Desert Bugs (Hemiptera: Heteroptera: Thaumastellidae): New records and review of the distribution and habitat of this relict group, Zootaxa 5541 (2), pp. 144-162 : 150-153

Thaumastella namaquensis Schaefer & Wilcox, 1971

( Figs 4–5 , 9–10 , 13 )

Thaumastella namaquensis Schaefer & Wilcox, 1971: 207–213 , Figs 1–4 (original description, morphology, habitat, distribution). Holotype: ♂, Namibia: 10 miles N of Vioolsdrift, Gt. Namaqualand (TMSA).

Thaumastella namaquensis : Schaefer (1975): 230, 235 (trichobothria); Jacobs (1986): 142 –144 (habitus drawing, habitat); Jacobs (1989): 302, 305–314 (differential diagnosis, morphology, karyotype, habitat, distribution); Jacobs (2008): 142 –144 (habitus drawing, habitat); Jacobs et al. (1989): 459 –463 (composition of metathoracic scent gland secretion); Kerzhner et al. (2004): 17 (list of karyotypes); Grazia et al. (2008): 6, 8, 11, 13, 23–26, 28–31, Figs. 8 (morphology, phylogenetic analysis); Pluot-Sigwalt & Lis (2008): 299, 305 (spermatheca); Wu et al. (2016): 756 –757 (phylogenetic analysis); Lis et al. (2017): 485, 490–492 (phylogenetic analysis); Rider et al. (2018): 135 (biology); Weirauch et al. (2019): 74, 78, 81–82, 93–94, Fig. 3 (phylogenetic analysis, habitus photo); Bianchi et al. (2021): 414, 416, 418 (molecular phylogeny); Roca-Cusachs et al. (2022): 41 (phylogenetic analysis).

Type material examined. Holotype: ♂ ( Fig. 4 ), NAMIBIA: ‘ 10 m N of Viools- / drift, Gt.Namaqua- / ld.; 13: IX.1950 / C. Koch, G. van Son [printed]; TVL [printed] / 1697 [printed] / COLLECTION / TRANSVAAL / MUSEUM [printed, pale blue label] / Thaumastella / namaquensis / Schaefer & Wilcox [handwritten] / HOLOTYPE [printed, red original type label] // HOLOTYPE Hem096 / Thaumastella / namaquensis / Schaefer & Wilcox [printed; red type label added by museum]’ ( TMSA). Paratypes: 2 ♂♂ 2 ♀♀, same data as holotype ( TMSA).

Additional material examined. NAMIBIA: Hardap Region: S.W.Afr., Naukluft, Felseneck reserve, 24.21°S 16.04°E, light collection, 24.x.1974, E-Y: 416, 1 ♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA). || Kharas Region: Keetmanshoop Dist.: Gellap Agr. Exp. Station, 26°24′42.2″S 18°00′45.0″E, 1080 m a.s.l., 16.–23.x.2002, pifall trap E6, BIOTA, 1 ♀, A. Hoffmann lgt., J. Deckert det. ( ZMHB); Keetmanshoop Distr. Gellap Ost, 1100 m a.s.l., 26°24′26″S 18°00′38″E, 24.x.2002, 6 ♂♂ 6 ♀♀, 9.ix.2008, 8 ♂♂ 1 ♀, J. Deckert lgt. & det. ( Fig. 5 , ZMHB); Keetmanshoop Distr.: Gellap Ost 3, 23 km NW Keetmanshoop, dwarf shrub savannah (Nama-Karoo), BIOTA 10.005.2001.7.05.572, 26°24′06.4″S 18°00′38.6″E, 10 pitfall traps, 5.–10.iv.2001, 12.00–12.00, 5 ♂♂ 3 ♀♀, M. Uhlig & E. Marais lgt., J. Deckert det. 2003 ( ZMHB); ditto, BIOTA 10.005.2001.7.11.1005, 26°24′06″S 18°00′38″E, singling, 7.iv.2001: 13.30, 32 °C, 12 ♂♂ 1 ♀, J. Deckert lgt. & det. 2003 ( ZMHB); BIOTA 10.005.2001.7.11.1005, 26°24′06″S 18°00′38.2″E, singling, 7.iv.2001: 10:30, 6 ♂♂ 3 ♀♀, J. Deckert lgt. & det. 2003 ( ZMHB); ditto, BIOTA 10.000.2001.7.11.1001, 26°24′26.5″S 18°00′34.2″E, singling, 7.iv.2001: 10.30, 3 ♂♂ 1 ♀, J. Deckert lgt., D. H. Jacobs det. ( DHJS); BIOTA 10.049.2001.7.11.551, 26°24′18.5″ 18°00′25.5″E, singling, 8.iv.2001: 12.30, 30 °C, 2 ♂♂, Uhlig, Ebert & Deckert lgt., J. Deckert or D. H. Jacobs det. (1 ♂ DHJS, 1 ♂ ZMHB); Keetmanshoop Distr.: Nabaos 7 (Nuwe Fontein), 24 km NW Keetmanshoop, dwarf shrub savannah (Nama-Karoo), BIOTA 11.031.2001.7.05.571, 26°23′38.1″S 17°59′50.0″E, 10 pitfall traps, 5.–10.iv.2001, 16.00–10.00, 1 ♂ 1 ♀, M. Uhlig & E. Marais lgt., J. Deckert det. 2003 ( ZMHB); ditto, BIOTA 11.031.2001.7.05.298, 26°23′45.8″S 17°59′47.5″E, pitfall traps, 4.–8.iv.2002, 1 ♀, M. Uhlig lgt., J. Deckert det. ( ZMHB); S.W. Afr., S Namib, Rosh-Pinah, 27.53°S 16.50°E, from under stones, 21.ix.1973, 1 ♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA). SOUTH AFRICA: Northern Cape: S. Afr.; Richtersveld, Hellskloof, 4 km N, 28.17°S 16.59°E, 26.ix.1991, E-Y: 2798, from under stones, 9 ♂♂ 9 ♀♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA); S. Afr.: Richtersveld, Helskloof, 28.20°S 16.59°E, 7.ix.2001; E-Y: 3414, under stones & ground, 9 ♂♂ 5 ♀♀, SATM staff leg., D. H. Jacobs det. ( TMSA); S. Afr., Richtersveld, Ganakom Riv. Valley, 28.26°S 17.12°E, 5.ix.1976; E-Y: 1221, ground trap with faeces bait, 35 days; 1 ♂, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA); ditto, E-Y: 1221, from under stones, 1 ♂ 3 ♀♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA); S. Afr., Richtersveld, Ekstienfonteinvall (= Eksteenfontein valley?), 28.47°S 17.12°E, 28.ix.1991; E-Y: 2804, from under stones, 1 ♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA); Anenous Pass nr. Steinkopf, 29°13′S 17°37′E, 1.x.2002, 3 ♂♂, D. Jacobs & M. Stiller lgt., D. H. Jacobs det. ( DHJS); RSA: Northern Cape Province, Steinkopf, 29°16′31″S 17°44′43″E, 11.ix.2008, 5 ♂♂ 4 ♀♀, J. Deckert lgt., J. Deckert & D. H. Jacobs det. (2 ♂♂ 2 ♀♀ DHJS, 3 ♂♂ 2 ♀♀ ZMHB); Steinkopf, roadsite, 800 m a.s.l., 29°16′58.980″S 17°44′56.880″E, 11.ix.2008, 3 ♂♂ 4 ♀♀, J. Deckert lgt. & det. ( ZMHB); nr. Spektakel Pass, 29°41′S 17°39′E, 16.ix.1984, 8 ♀♀, D. H. Jacobs lgt. & det. ( DHJS); nr. Spektakel Pass, Namaqualand, 29.42°S 17.42°E, 7.iv.1985, 2 ♂♂ 6 ♀♀, D. H. Jacobs lgt. & det. ( DHJS); Farm Deurdrift nr. Springbok ( Figs 6–7 ), 29.45°S 17.56°E, 6.–13.iv.1985, 15 ♂♂ 22 ♀♀, D. H. Jacobs lgt. & det ( DHJS); ditto, 13.–17.ix.1984, 2 ♂♂ 10 ♀♀, D. H. Jacobs lgt. & det. (2 ♂♂ 10 ♀♀ DHJS, 2 ♂♂ 2 ♀♀ BMNH); S. Afr., Namaqualand, Springbok, 18 km, 29.47°S 19.50°E [error on label, should be 17.50°E], 26.viii.1977; E-Y: 1334, ground traps with faeces bait, 61 days; 2 ♀♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA); S. Afr., Namaqualand, Mesklip, 29.49°S 17.52°E, 26.viii.1977; E-Y: 1335, ground traps, 61 days, 1 ♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA); S. Afr., Namaqualand, Springbok, Mesklip, 29.49°S 17.52°E, 30.viii.1976; E-Y: 1184, ground traps with meat bait, 43 days, 2 ♂♂ 6 ♀♀, Endrӧdy-Younga lgt., D. H. Jacobs det. ( TMSA). S. Africa (16), Hester Malan N. R., 10 mls. E Springbok, under cut lucerne [ Medicago sativa , Fabaceae ], 7.–8.i.1972, 1 ♂, Southern African Exp. 1972-1, W. Dolling det., P. Kment revid. ( BMNH).

Habitat. Sweet, in Schaefer & Wilcox (1971), provided the following description of the habitat at Springbok: ‘This area is delimited as the biotic Province of Little Namaqualand, with low precipitation which falls chiefly during the winter months. The low vegetation is correspondingly largely a karoo flora with some Cape elements; the period of major biotic activity is early spring. The collecting site was a bouldery hillside with a sunny northwest exposure and a slope of about 20°. Kokerboom [= Quiver] trees ( Aloe dichotoma Masson [= Aloidendron dichotomum ; Asphodelaceae ]) occurred on top of the hill. The perennial plants consisted primarily of succulent Euphorbiaceae and Mesembryanthemum [ Aizoaceae ] and at this time, many drying and dying ephemerals, mostly Asteraceae . Grasses were very infrequent and large areas of bare sandy soil were present. Thaumastella was found just underground in small chambers about 1″ by 5″ [= 25.4– 127 mm] in soft sandy soil along the margin of a boulder. Five or six bugs were found together in a group and two were found singly. The thaumastellids were very lygaeid-like in their movements and were initially taken to be a Plinthisus [Stephens, 1829, Rhyparochromidae ] or a small blissine [ Blissidae ]. In the laboratory, the thaumastellids spent most of the time hiding as a group under a flake of bark. The insects fed readily on sunflower, and peanut and some small seeds from the habitat, and grew fairly fat, swelling the abdominal conjunctiva. Although the insects lived for three months in the laboratory, no mating was observed and no eggs were laid. This suggests that the insects were in reproductive diapause and may have already completed their life cycle by mid-September’ (Sweet in Schaefer & Wilcox 1971).

Jacobs (1989) descibed the habitat and bionomics of Th. namaquensis as follows: At Springbok ( Figs 6–7 ) most of the specimens were collected under fairly large stones in cavities which are exposed when the stones are removed. Single specimens were also collected on the ground near the stones, especially at dusk, but individuals of Th. namaquensis seemed reluctant to leave their sheltered environment. Even night visits, to the spots where they were abundant produced no individuals above-ground. It is possible that they live on seeds that are accumulated by the wind against the stones and very seldom leave their shelters. Although they were found at scattered spots they seemed to be especially abundant where a few suitable stones were present in or near old or existing sheep and goat kraals, despite different species of plants were present in the kraals at Deurdrift and Spektakelberg. It is possible that the manure and moisture supplied by the sheep and goats could maintain better seed-producing vegetation in this arid region to the advantage of the bugs which are almost certainly seed-eating.

Jürgen Deckert and colleagues collected Th. namaquensis in Namibia with pitfall traps filled with ethylene glycol on two different locations, one was heavily grazed by sheep and goats (Nabaos) while in the other (Gellap Ost) there were no sheep or goats, but instead, there was a better developed vegetation where more specimens were found (J. Deckert, pers. observ.).

A few of the specimens were collected by means of ground traps, some of them baited by faeces or meat; it remains a question if these events were merely an accident or that Thaumastella is occassionally using such diet as it is know in many other Pentatomomorpha species (e.g., Payne et al. 1968, Adler & Wheeler 1984, Booth 1990, Chérot et al. 1998, Voigt 2001, López et al. 2009, Baz et al. 2010, Ekanem & Dike 2010, Eger et al. 2015, Valcárcel & Goula 2018).

Phenology. Collected regularly in April and August to October ( Schaefer & Wilcox 1971, Jacobs 1989, this paper), with exception of a single specimen found in January (this paper). Although August to September is the time of year when most of the plants of this winter rainfall area produce flowers and seeds, thaumastellid nymphs were only found during April. Nymphs of all stages were found together with the adults (Jacobs 1989). The collection dates are probably not a true reflection on when the species occur or are active but the result of the fact that most collecting in Namaqualand is done in August to October when most plants grow and actively flower. Most probably the bugs are around all year round, but are less active and mostly underground and under stones in the winter.

Distribution ( Figs 9, 10 ). AFROTROPICAL REGION: Namibia: Hardap, ||Kharas ( Schaefer & Wilcox 1971, this paper), South Africa: Northern Cape ( Schaefer & Wilcox 1971, Jacobs 1989, Jacobs et al. 1989, this paper).

According to Schaefer & Wilcox (1971), the type series of Th. namaquensis is from Vioolsdrift, near the Orange River near the southern end of the Namib Desert, which is a very dry area (1.5 in. [= 38.1 mm] annual rainfall) with scant vegetation. The specimens collected near Springbok, about 75 miles [= 120.7 km] south of Vioolsdrift, comes from a little less dry area (8–10 in. [= 203.2– 254 mm] annual rainfall). The annual average precipitation in Gellap Ost is about 150 mm per year ( Berger et al. 2010).

Figures

FIGURE 8. Landscape where an undescribed Thaumastella species was collected near Beaufort West in the Karroo, South Africa. (Photo: D. H. Jacobs).

FIGURES 3–5. Habitus of South African Thaumastella species. 3—Th. elizabethae Jacobs, 1989, holotype ♂ and its labels; 4—Th. namaquensis Schaefer & Wilcox, 1971, holotype ♂ and its labels; 5—living specimen of Th. namaquensis, Namibia, Gellap, 9.ix.2008. (Photos: 3–4—D. H. Jacobs, 5—J. Deckert).

FIGURES 9–11. Distribution maps of Thaumastella species: 9—general view; 10—detailed distribution of Th. aradoides Horváth, 1896 in North Africa and Near East; 11—detailed distribution of Th. elizabethae Jacobs, 1989, Th. namaquensis Schaefer & Wilcox, 1971 and Thaumastella sp. nov. in Namibia and South Africa.

FIGURES 12–13. Comparison of distribution of Thaumastella aradoides Horváth, 1896 (12) and the South African species of Thaumastella (13), Th. elizabethae Jacobs, 1989, Th. namaquensis Schaefer & Wilcox, 1971 and Thaumastella sp. nov., compared to ecoregions according to Shorthouse (2010).

FIGURES 1–2. Habitus of Thaumastella aradoides Horváth, 1896. 1—holotype ♀ (2.40 mm) and its labels; 2—♀ (2.25 mm) from Saudi Arabia: Wadi Eidabi. (Photos: 1—P. Kóbor, 2—A. Carapezza).

FIGURES 6–7. Habitat of Thaumastella namaquensis Schaefer & Wilcox, 1971, South Africa, Farm Deurdrift near Springbok. (Photos: D. H. Jacobs).