Higher Systematics of the Pentatomoidea 133
somewhat flap-like (Figure 2.2A); the rostrum is also short, usually not surpassing the middle coxae.
The humeral angles may or may not be prominent; the posterior margin of the pronotum extends over
the base of the scutellum, sometimes greatly so (Figure 2.2E). The scutellum is subtriangular, not cov-
ering the coria, and the apex is usually pointed. The veins of the hemelytral membrane are subparallel
(Figure 2.2E), not reticulate, but closed cells are present along the basal margin in several species; the
hind wing has a hamus. Several tessaratomids possess a stridulatory mechanism composed of a strigil on
the posterior anal vein (postcubitus in several earlier papers) of the hind wing and a plectrum located on
abdominal tergum I; this structure is apparently lacking in the Oncomerinae. One of the characters used
most often for defining the tessaratomids is that most species have the spiracles on abdominal sternite
II completely exposed (said to be covered by the posterior margin of the metapleura in other families)
(Figure 2.2B), but this character seems to be a matter of degree. It is exposed or partially exposed in a
number of species in other families and, thus, seems somewhat unreliable for defining this family. The
metasternum often is produced laterad and anteriorly, sometimes reaching the fore coxae; its posterior
margin is truncately abutted to the base of the abdomen (Figure 2.2C). The metathoracic scent gland
ostiole is oval and accompanied by a spout-shaped ostiolar ruga (Oncomerinae) (Figure 2.4D), or it is
wide and groove-shaped and accompanied by a bilobate ostiolar ruga (Tessaratominae + Natalicolinae)
(Figure 2.4C) (Kment and Vilímová 2010a). The tarsi may be two- (Natalicolinae) or three-segmented
(Oncomerinae, Tessaratominae). The abdominal trichobothria are arranged transversely on each side of
abdominal sternites III through VII and are located posterior to the spiracles and mesad of the spiracu-
lar line. The ninth paratergites are greatly enlarged. The female spermatheca lacks a sclerotized rod;
the spermathecal bulb is simple, ball-shaped, and lacks diverticula. Nine species of tessaratomids have
been karyotyped, of which seven and two had a diploid number of 10 + XY and 12 + XY, respectively
(Ueshima 1979, Kerzhner et al. 2004, Rebagliati et al. 2005).
At present, the Tessaratomidae contains 62 genera and 252 species (Table 2.2). The distribution
is mostly Old World, with only three species of Piezosternum (Figure 2.16L) occurring in the New
World. There have been four fossil species described in the Tessaratomidae. Two are members of the
extant genus Pycanum (Piton 1940). The other two (Latahcoris spectatus Cockerell, Tessaratomoides
maximus Jordan) were placed in new genera (Cockerell 1931, Jordan 1967); one of the new genera
(Tessaratomoides) may not be available, however, as it was proposed in name only; that is, it was not
formally described (see discussion of Jordan 1967 names in Section 2.2.10.7.47).
Based on the literature, mainly the works of Leston (1955b, 1958) and Kumar (1969a,b, 1974b), Rolston
et al. (1994), in their World catalog, recognized three subfamilies (one of which was subdivided into
three tribes): the Natalicolinae, Oncomerinae, and the Tessaratominae (with the tribes Prionogastrini,
Sepinini, and Tessaratomini). Schuh and Slater (1995) recognized the same three subfamilies, but they
divided the Oncomerinae into two tribes (Oncomerini and Piezosternini), and the Tessaratominae into
five tribes (Eusthenini, Platytatini, Prionogastrini, Sepinini, and Tessaratomini). Sinclair (1989), in his
Ph.D. dissertation, provided a generic revision and a phylogenetic analysis of this family. The generic
revision of Oncomerinae, and the description of two new genera (one in the Oncomerinae, the other
in the Tessaratominae) have been published (Sinclair 2000a,b) but the phylogenetic analysis has not.
Although his phylogenetic analysis showed that the family is polyphyletic, and that the Oncomerinae
should be raised to family status, he later published the generic review in which he still treated the
Oncomerinae as a subfamily. In his study, the remaining members of the Tessaratomidae were placed
into two subfamilies: the Tessaratominae and the Natalicolinae, the latter further divided into two tribes
(Natalicolini and Prionogastrini). Grazia et al. (2008), in their analysis based only on morphology, and
their analysis combining both morphological and molecular data, found that the Tessaratomidae was
monophyletic, and, in all analyses, the Tessaratomidae was the sister group with the Dinidoridae, a
result suggested by Gapud (1991). The intrafamiliar classification recently was discussed by Kment and
Vilímová (2010a) suggesting the monophyly of Tessaratominae + Natalicolinae (= Tessaratomidae sensu
stricto) and Dinidoridae + Tessaratomidae sensu lato, but the relationships among Tessaratomidae sensu
stricto, Oncomerinae, and Dinidoridae remain unresolved. Neither the monophyly of the Tessaratomidae
sensu lato nor the Dinidoridae + Tessaratomidae sensu lato clade were confirmed by Wu et al. (2016).
Other than an older work on the African Tessaratomidae (Schouteden 1905a) and the more recent com-
prehensive studies on the Australian oncomerines by Leston and Scudder (1957) and Sinclair (2000a,b),