Callostethus Ruckes, 1961

Fernandes, José Antônio Marin, Grazia, Jocélia & Campos, Lourival Dias, 2011, Redescription of Callostethus Ruckes, 1961 (Hemiptera: Heteroptera: Pentatomidae: Discocephalinae) with the description of C. flavolineatus sp. nov., Zootaxa 2866, pp. 55-60 : 56

Callostethus Ruckes, 1961

Callostethus Ruckes, 1961: 153–154; 1964: 58.

Type species: Edessa guttatopunctata Fabricius, 1803 (orig. desig.)

Body oval, medium-sized (around 10 mm long), ochraceous to dark castaneous. Punctures shallow, darker than body, dense and uniformly distributed. Scutellum with a pair of calloused yellow spots at base. Ventral surface of abdomen with small dark spots to uniformly dark castaneous; punctures shallow and dense.

Head wider than long (around 1.5 times) and flattish with some calloused yellow dots. Eyes protruding but not pedunculate. Margin with a small tooth and evenly arcuate, in front of it. Juga longer than tylus and overlapping in front of it. Buccula low, parallel, and long covering most of gula. Rostrum reaching abdominal segment III or IV, segment I reaching procoxae, segment II as long as III and IV combined. Antennae five-segmented, antennal tubercle armed with a tiny spine, segment I reaching apex of the head, segment II shorter than I, segment III shorter than IV but four times longer than II, segments IV and V subequal in length.

Pronotum wider than long with some calloused yellow spots on anterior half and without a collar. Anterolateral margin straight and emarginated with a minute tooth on anterior angle. Humeral angles obtuse and not produced. Apex of scutellum obtuse reaching abdominal segment IV in females and VII in males. Evaporatorium darker than body, dull and coarsely rugose. Peritreme short, digitiform, and straight; peritremal surface prolonged as a narrow rugae reaching middle of the pleura. Mesosternum slightly tumid with a narrow, obtuse, low subcalloused carina reaching metasternum; apical margin narrow and angulate. Metasternum rhomboidal with anterior and posterior margins narrow and angulate. Metapleura with a remarkable calloused yellow or reddish margin. Distal angle of corium surpassing apex of scutellum. Membrane of hemelytra dark and rounded. Seventh abdominal segment in male with its margin bordered by a wide membrane and a median retrorsely produced process (mp). Legs castaneous with a few long hairs and no punctures or dots.

Male (Figs. 1–2). Dorsal rim (dr) of pygophore slightly projected and concave medially. Lateral side of pygophore, close t e base of posterolateral angles, covered with long hairs. Posterolateral angles (pl) cuneiform, subparallel, posteriorly produced, with a basal scar resembling an articulation. Ventral rim (vr) projected in processes as long as posterolateral angles, parallel and fused with them. Ventral surface with a distinct medial impression close to ventral rim. Base of the genital chamber with a pair of semimembranous arms parallel to proctiger (ma). Proctiger (X) with a distinct membranous dorsal area and a pair of distal small and flat projections (pp). Posterior face of proctiger rugose, lateral margins ridged. Paramere (pa) uncinate and curved over ventral rim.

Female. Only the female of C. guttatopunctatus is known, see description below.

Comments. Ruckes (1961) described Callostethus in comparison with Mecistorhinus and Antiteuchus . Ruckes (1964) provided a key to separate the four closely allied genera, adding Parantiteuchus Ruckes, 1962 in the comparison. Parantiteuchus was studied by Fernandes & Grazia (2002) and distinguished from Antiteuchus by the male genitalic characters. We agree with Ruckes (1961) that Callostethus is closely allied to Antiteuchus and both are different of Mecistorhinus ( Fernandes & Grazia 2006) . Some characteristics that distinguish Callostethus and Antiteuchus from Mecistorhinus are the following, found in the latter genus: head longer than wide; rostrum nearly reaching the apex of abdomen; terminal abdominal tergite in male without a membrane or median retrorse process; dorsal rim of pygophore not sinuate; proctiger completely sclerotyzed. Callostethus can be distinguished from Antiteuchus by: mesosternum slightly tumid, but provided with a median low subcalloused carina (feature that names the genus); metasternum rhomboidal; metapleuron with a remarkable calloused area yellow or reddish; ventral rim of the pygophore projected dorsally and fused with posterolateral angles; parameres uncinate and curved over ventral rim; and the presence of a pair of semimembranous arms close to proctiger.