Thaumastella
| Thaumastella | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Thaumastellidae | ||||||||||||
| Horvath , 1896 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Thaumastella | ||||||||||||
| Štys , 1964 |
Thaumastella is the only genus of the Thaumastellidae familywithin the bug suborder Pentatomomorpha . 3 types are known of it.
features
The bugs are a maximum of 3.5 millimeters long. They have a somewhat flattened, elongated, brown-colored body and their appearance is reminiscent of some ground-dwelling species of ground bugs (Lygaeidae). In this family wing dimorphism is observable; there are species with brachypter (short-winged) and macropter (fully developed) winged individuals.
The mouthparts on the head are directed forward (porrect). The head has rounded side edges, the labium is four-limbed, the first limb being hidden within the groove of the buccula. The antennae are five-part. They are angled between the second and third segments, whereby the feelers are not movable like a joint. The triangular scutellum is not enlarged. The olfactory gland canal is elongated and sometimes extends almost to the dorsal edge of the metapleuron. The adjacent evaporation area is large and extends to the rear area of the mesopleuron. The hemielytral corium in individuals with fully developed wings is divided into an exo- and endocorium, with a furrow running along the medial artery. Both areas are rounded off at the back. The membrane extends a little between the two areas. The two clavias form a seam adjacent to one another. The membrane of the forewings has only reduced veins and no bifurcated veins. In flightless species, the forewings are reduced to short stumps, similar to the upper wings of the short-winged species . These have a straight rear edge and are without a membrane, making these species of ground bugs look similar to the Plinthisini tribe . A crest of flattened setae is formed on the hips ( coxes ) . The rails ( tibia ) of the forelegs are thorny, all tarsi have three limbs. The inner laterotergites are missing on the third to seventh abdominal segments. The stigmata on the abdomen are all on the ventral side. The nymphs have three pairs of scent gland openings on the back of the abdomen, which lie between the third to sixth tergum . The third to sixth sternum on the abdomen has two pairs of Trichobothria on each side in oblique rows . In Thaumastella aradoides and Thaumastella elizabethae the seventh sternum has two individual Trichobothria each, in Thaumastella namaquensis there are two pairs. The seventh sternum is not divided in the females, the valvulae of the ovipositors are plate-shaped. The spermatheca has a long, coiled canal; the pump flange-like part is variable. Both the distal and the proximal flange can be formed or absent.
All members of the family have a well-developed organ of stridulation. This is formed by a well sclerotized edge on the underside of the hind wings, which lies above the first tergum of the abdomen, which in turn bears the extremely fine, obliquely-edged, approximately oval counterpart near the anterolateral edge.
The eggs are large and ovoid. They are half the size of the females' abdomen.
Occurrence
The family has a disjoint range that includes North Africa, the Middle East, and semi-deserts in Southwest Africa.
Way of life
The animals were discovered in pits beneath stones. Since they were mainly only found there and at night in the immediate vicinity, it is assumed that they feed on seeds that strong winds blow into these pits. At least Thaumastella elizabethae was observed sucking on the seeds of Pharnaceum aurantium outside the pits . The bugs carried the seeds around on the ground by their mouthparts.
Taxonomy and systematics
Horvath first described the group as a genus of ground bugs in 1896. It was not until 1960 that Seidenstücker noticed that the morphology of the ovipositor did not match the ground bugs. Pavel Štys placed the then only known species, Thaumastella aradoides, into a family of its own. The group is similar to the earth bugs (Cydnidae) and was considered by some authors as a subfamily within them. The exact family status has not yet been clarified. An investigation based on morphological features and DNA sequences from 2008 by Grazia et al. could not bring any clarity about the kinship of the group, although this has shown very well that they are to be placed within the Pentatomoidea (and not the Lygaeoidea). Due to the ambiguity of the result, Grazia et al. the positioning of the group as an independent family within the Pentatomoidea is provisionally justified.
The family includes the following three types:
- Thaumastella aradoides Horvath, 1896 (North Africa, Middle East)
- Thaumastella elizabethae Schaefer & Wilson, 1971 ( Namaqualand , Richtersveld , Namibia)
- Thaumastella namaquaensis Jacobs, 1989 ( Namaqualand , Richtersveld , Namibia)
supporting documents
Individual evidence
- ↑ a b c d e f g h i R.T. Schuh, JA Slater: True Bugs of the World (Hemiptera: Heteroptera). Classification and Natural History. Cornell University Press, Ithaca, New York 1995, pp. 243ff.
- ↑ Jocelia Grazia, Randall T. Schuh & Ward C. Wheeler: Phylogenetic relationships of family groups in Pentatomoidea based on morphology and DNA sequences (Insecta: Heteroptera). Cladistics 24, pp. 932-976, 2008
literature
- RT Schuh, JA Slater: True Bugs of the World (Hemiptera: Heteroptera). Classification and Natural History. Cornell University Press, Ithaca, New York 1995.