Tiridates Stal 1867

Eger, J. E., 1987, A Review of the Genus Tiridates Stal (Heteroptera: Pentatomoidea: Scutelleridae), The Florida Entomologist 70 (3), pp. 687-716 : 341-343

Tiridates Stal 1867

Tiridates Stal, 1867, p. 494 (keyed, Pachycoris rubrocinctus and P. flavicinctus in­cluded); Stal, 1870, p. 13-14; Distant, 1880, p. 18 (described, distribution); Schoute­den, 1904, pp. 68-69 (described, keyed); Kirkaldy, 1909, p. 278, 365.

Medium-large (10.8-14.8 long), elongate oval, strongly convex above and below; dor­sal surface glabrous, punctation fine, moderately dense, most dense on head and an­terior border of pronotum. Ventral punctation dense, coarse on head and pronotum, sparse medially on abdomen, becoming more dense laterally.

Head: convex, moderately declivent, gradually narrowing apically, apex narrowly rounded; lateral margins of juga sinuous, borders rounded. Tylus slightly surpassing juga; first antennal segment not reaching apex of head. First rostral segment longer than bucculae. Bucculae abruptly curving dorsad at posterior limit, rounded anteriorly. Antennae 5-segmented, arising midway down lateral surface of head and just anterior of eyes, terminal two segments not distinctly flattened.

Thorax: anterior, anterolateral and posterior margins of pronotum slightly concave, posterolateral margins convex; small tooth present at each anterolateral angle; an­terolateral margins rounded dorsoventrally, not compressed or carinate. Pronotum evenly rounded dorsally in lateral view. Prostethus entire. Tibiae sulcate. Ostiole aris­ing nearer to metacoxae than to lateral margin of metapleuron. Ostiolar rugae auricu­late, extending 1/3 or less of distance from ostiole to lateral margin of metapleuron, roughly 3 to 5 times as long as width of ostiole (Fig. 2). All sterna sulcate, rounded laterally, not distinctly carinate. Scutellum constricted basally; basal 1/2 to 1/3 of lateral margins of hemelytra exposed.

Abdomen: lateral margins of connexiva evenly rounded. Abdominal sternites with slight lateral submarginal impression; small rounded projection present laterally at pos­terior extremity of each segment. Striated area present on third to fifth visible abdom­inal sternites.

Pygophore concealed by sixth visible abdominal sternite, caudal face with distinct projection in lateral aspect (Fig. 12); each lateral wall of pygophore with bifurcate process, thecal plate attached to anterior arm of process (Fig. 11). Paramerehookshaped (Fig. 10). Theca with two elongate sclerotized processes; vesica elongate, finely spiculate (Fig. 8).

Sixth visible abdominal sternite expanded to conceal female genital plates, posterior margins of eighth and ninth paratergites narrowly exposed (Fig. 1). First gonocoxae bilobed, sclerotized posterior lobe narrow, elongate (Fig. 21); anterior lobe membranous with elongate sclerotized band along posterior margin. Ninth paratergites thin,moder­ ately elongate. Genital chamber with sclerotized groove and two large sclerotized plates on floor of genital chamber. Spermathecal duct with large spherical dilation; pump distinct, with well defined proximal and distal flanges; spermathecal bulb spherical, connected to pump by long stout duct (Fig. 26).

Type Species: Pachycoris rubrocinctus Herrich-Schaeffer, 1837 , by subsequentdesigna­tion ( Schouteden 1904). Kirkaldy (1909) also listed P. rubrocinctus as the type species (p. 278), but subsequently (p. 365) designated Pachycoris flavicinctus Herrich-Schaef­fer, 1837, as the type species. Kirkaldy (1909 p. XXXIV) believed that P. flavicinctus should be the type species because Stal (1870) doubted the specific distinction of P. rubrocinctus . However, at the time Stal described Tiridates (1867), both P. rub­rocinctus and P. flavicinctus were included and both are available to be the type species. Schouteden's designation of P. rubrocinctus was the first valid designation making P. rubrocinctus the type species of the genus.

Distribution: Tiridates ranges from northern Mexico (Tamaulipas), south to Guatemala and Nicaragua. It is generally uncommon in collections, most of the material examined being from Mexico.

Types: Dr. Martin Baehr of the Zoologische Staatssammlung, Munich has informed me that the Herrich-Schaeffer types for Pachycoris flavicinctus , P. rubrocinctus , and P. mexicanus could not be located and were probably destroyed by war action.

Comments: The female genitalia are unusual in Tiridates , having bilobed first gonocoxae and sclerotized plates on the floor of the genital chamber. Bilobed first gonocoxae are also found in Agonosoma ( Scudder 1959) .

Specimens of Tiridates exhibit considerable intra-specific variation in color patterns and few useful taxonomic characters other than the genitalia. Some color patterns were used in the following key and appeared to be consistent. However, dissection of genitalia is recommended for definitive determination of species. The male aedeagus is diagnostic. The sclerotized plates on the floor of the female genital chamber are somewhat variable, but are usually useful for recognition of species.

Virtually nothing is known of the biology of species of Tiridates .

Key to species of Tiridates

1. Abdominal venter predominately dark brown to black, usually with basal yellow to red macula, and scutellum bordered laterally and posteriorly by continuous yellow to red vitta; thecal processes acute apically ( Fig 8 ) ........... 2.

1 '. Abdominal venter predominately yellow to red, with dark brown to black transverse vitta present basally and longitudinal vitta present laterally; or venter black and scutellum with lateral marginal vittae incomplete; apex of each thecal process hatchet-shaped ( Fig. 16 ) ........................ T. mexicanus .

2. Thecal lobes short, not encircling vesica ( Fig. 8 ); Mexico, north and west of the Isthmus of Tehuantepec ............................. T. rubrocinctus rubrocinctus .

2. ' Thecal lobes long, encircling vesica ( Fig. 13 ); Mexico, south and east of the Isthmus of Tehuantepec into Nicaragua ................. T. rubrocinctus schaffneri.

Figures

Figs. 7-14. 7-12. Tiridates rubrocinctus rubrocinctus. 7.) Aedeagus, dorsal aspect; vesica (V); thecal process (TP); thecal lobe (TL). 8.) Aedeagus, lateral aspect. 9.) Proctiger, caudal aspect. 10.) Right paramere, lateral aspect. 11.) Genital cup, caudal aspect, omitting parameres and proctiger; anterior lobe of pygophoral process (A); posterior lobe of pygophoral process (P). 12.) Genital cup, caudal margin, lateral aspect. 13-14. Tiridates rubrocinctus schaffneri. 13.) Aedeagus, lateral aspect. 14.) Right paramere, lateral aspect. Dimensional lines equal 1.0 mm.

Figs. 15-20. Tindates mexicanus. 15.) Aedeagus, dorsal aspect; vesica (V); thecal process (TP). 16.) Aedeagus, lateral aspect. 17.) Proctiger, caudal aspect. 18.) Right paramere, lateral aspect. 19.) Genital cup, caudal aspect, omitting parameres and proctiger; anterior lobe of pygophoral process (A); posterior lobe of pygophoral process (P). 20.) Genital cup, caudal margin, lateral aspect. Dimensional lines equal 1.0 mm.