Thyanta Stal 1862

Thyanta Stal 1862 View in CoL

Thyanta Stal, 1862a:58 ; Stal, 1867:529; Stal, 1872:34-35; Distant, 1880:65; Summers, 1898:45; Kirkaldy, 1909:94; VanDuzee, 1917:5 l; Blatchley, 1926: 104, 112- 113; Jensen-Haarup, 1928:185- 186; Furth, 1974:21-22; Froeschner, 1981:71; McPherson, 1982:48, 76-77; Rolston and McDonald, 1984:74, 76; Froeschner, 1988: 592.

Type species. Cimex perditor F., 1794 (by subsequent designation, Kirkaldy, 1909: XXX).

Diagnosis. Third (second visible) abdominal stemite lacking medial spine or tubercle. Each ostiolar ruga sulcate proximally, reaching at least three-fourths distance from mesial margin of ostiole to lateral margin of metapleuron. Bucculae evanescent or arcuately truncate at posterior terminations. Juga and tylus usually subequal in length; rostrum reaching at least to metacoxae. Femora unarmed; superior surface of each tibia usually sulcate. Width of scutellum at distal end of frena two-fifths or less basal scutellar width. Each paramere narrowly rounded to acute apically, lacking denticles, usually lacking lateral lobe, rarely with spinose lateral lobe.

Comments. The genus Thyanta is closely related to two other pentatomine genera, Cyptocephala Berg and Tepa Rolston and McDonald, from which it can be separated reliably only by differences in the male genitalia. In all northern hemisphere species of Thyanta , the head of each paramere lacks a lateral lobe. In Cyptocephala and Tepa , the parameres have well-developed lateral lobes. Cyptocephala further differs from Tepa and Thyanta by having minute denticles between the lateral lobe and the apex of the paramere. The parameres of species of Tepa and Thyanta lack denticles. Jensen-Haarup (1928) described the subgenus Parathyanta within Thyanta . Rolston and McDonald (1984) placed Parathyanta in the synonymy of Cyptocephala . At the same time, they transferred 4 species from Thyanta to Cyptocephala and 6 species from Thyanta to Tepa . The species of both Cyptocephala and Tepa have been reviewed recently ( Rolston, 1972, 1986; Rider, 1986a).

The genus Thyanta is divided into three subgenera: Argosoma Rider , Phacidium Breddin , and Thyanta . All 8 species of the subgenus Phacidium are restricted to South America and have been treated in an earlier paper ( Rider and Chapin, 1991). Argosoma contains 20 species, 6 of which are known to occur outside South America. The nominate subgenus contains 9 species of which 7 are known to occur in the area covered by the present paper.

KEY TO SUBGENERA OF THYANTA STAL

I. Dorsal surface relatively shiny, glossy; punctures relatively large, sparse; pygophoral opening relatively large; posteroventral surface of pygophore produced into small, blunt, chin-like protuberance; ectal surface of each paramere concave; spermathecal bulb globose ................................................... Argosoma Rider Dorsal surface appearing matte, not shiny; punctures relatively small, dense; pygophoral opening relatively small, posteroventral surface of pygophore not produced into blunt, chin-like protuberance; ectal surface of each paramere convex; spermathecal bulb globose or digitiform...................................... 2

2(1). Pygophoral opening subtended by semicircular or rectangular impression; posterior margin of pygophore with medially emarginate production in middle; theca large, subtriangular, with small protuberance on each side near lateral dorsal margin; proximal end of sclerotized rod cone-shaped; spermathecal bulb digitiform ................................................................ Thyanta Stal Posteroventral surface of pygophore smoothly arcuate or with distinct sulcus, not with semicircular or rectangular impression; posterior margin of pygophore nearly transverse, lacking medial production; theca reniform, lacking protuberances on lateral dorsal margin; proximal end of sclerotized rod may be slightly swollen, but not cone-shaped; spermathecal bulb globose... Phacidium Breddin

KEY TO SPECIES OF THYANTA OCCURRING NORTH OF SOUTH AMERICA

l Anterolateral margins of pronotum piceous; mesial angle of each pronotal cicatrice black 2 - Anterolateral margins of pronotum not piceous; coloration of mesial angle of each pronotal cicatrice variable, often immaculate 3

2(1). Piceous markings along anterolateral pronotal margins relatively broad, usually easily visible from dorsal view; pygophoral opening subtended by semicircular impression; general form relatively broad (eastern U.S.) ............. calceata (Say) Piceous markings along anterolateral pronotal margins relatively narrow, not easily visible from dorsal view; pygophoral opening subtended by rectangular impression; general form relatively narrow (coastal plain from central Louisiana to Florida to New York) .................................. custator custator (Fabricius)

3(1). Humeral angles rounded to angulate, but never spinose 4 Humeral angles distinctly spinose.................................. 6

4(3). Dorsal punctation minute, dense, surface appearing matte; pygophoral opening subtended by rectangular impression; ectal surface of each paramere convex, lacking dorsomedial concave surface ( Fig. 34); spermathecal bulb digitiform ( Fig. 47) 5 Dorsal punctation coarse, sparse, surface glossy; posteroventral surface of pygophore produced into blunt chin-like protuberance; each paramere with dorsomedial surface concave ( Fig. 126); spermathecal bulb globose ( Fig. 136) ........ 10

5(4). Postspiracular black spot usually present on each side of each abdominal sternite and usually larger in diameter than adjacent spiracle; if absent or smaller than spiracle, then humeral angles usually angulate (eastern U.S.) ................................... .......................... custator accerra McAtee (part) Postspiracular area of each abdominal sternite immaculate; or, ifblack spot present, then spot is usually smaller in diameter than adjacent spiracle; humeral angles rounded, never angulate (western U.S.) ........................ pallidovirens (Stal)

6(3). Mesia! angle of each pronotal cicatrice often marked with black; posterolateral angle of each abdominal sternite usually black; pygophoral opening subtended by semicircular impression, posterior margin with distinct medial slit ( Fig. 71) 7 Without above black markings; pygophoral opening subtended by rectangular impression, posterior margin straight, concave, or sinuous, without medial slit ( Fig. 41) (southwestern U.S.; Mexico; Guatemala) ... custator accerra McAtee (part)

7(6). Complete or partial transhumeral reddish band usually present; both anterolateral and posterolateral angles of each abdominal sternite usually piceous.... 8 Reddish band between humeral angles usually absent; each abdominal sternite with anterolateral angle immaculate, each posterolateral angle with at most a small black spot......................................................... 9

8 (7). Humeral angles directed anterolaterad, usually approaching a 45 -degree angle with longitudinal axis of body ( Fig. 63) (southern U.S. to northern Argentina) ................................................................ perditor (Fabricius) Humeral angles directed primarily laterad and only slightly anterad ( Fig. 78) (Baja California, Mexico)........................ ........ spectabilis Ruckes

9(7). Yellow anterolateral pronotal margins contrasting with rest of pronotum; pronotal cicatrices immaculate; usually smaller than 9.0 mm long by 6.0 mm wide (Cuba; British West Indies)......................... ..... cubensis Barber & Bruner Anterolateral pronotal margins concolorous with rest of pronotum; mesial angle of each pronotal cicatrice usually black; usually larger than 9.0 mm long by 6.0 mm wide (Revillagigedo Islands, Mexico)....... ..... serratulata Ruckes

10(4). Southwestern U.S.; Mexico; Central America..................... 11 Southern Florida; West Indies........................... 12

11(10). Ostiolar canal narrowed at middle, becoming slightly wider towards apex ( Fig. 137); posterolateral angle of each abdominal sternite usually immaculate; apex of each paramere nearly spinose in medial view ( Fig. 124) (southwestern U.S.; northwestern Mexico)............................. ............ planifrons Ruckes Ostiolar canal acuminate apically; posterolateral angle of each abdominal sternite piceous, sometimes only a minute portion ofthe tip piceous; apex ofeach paramere narrowly rounded in medial view ( Fig. 140) (southern Texas; Mexico; Central America) ................................................ maculata (Fabricius)

12( I 0). Each paramere in medial view with apex straight or bending slightly ventrad ( Fig. 155), concave surface oriented more mediad than dorsad; posteromesial angles of basal plates distinctly excavated, resulting concavity broadly U-shaped ( Fig. 165) (Trinidad and Tobago; Venezuela) ........................... vadosa Rider Each paramere in medial view with apex curving slightly dorsad, orientation of dorsomedial concave surface variable; posteromesial angles ofbasal plates rounded or weakly emarginate.............. ............................. I 3

13(12). Concave surface of each paramere oriented more mediad than dorsad (southern Florida) ................................................. pseudocasta Blatchley Concave surface of each paramere oriented more dorsad than mediad.... 14

14(13). Apex of each paramere rounded in ectal view ( Fig. I 86); spermathecal duct with relatively small amount of swelling and coiling below proximal flange ( Fig. 197) (Greater Antilles) ............................................ obsoleta (Dallas) Apex of each paramere spinose in ectal view ( Fig. 20 I); spermathecal duct with large amount ofswelling and coiling below proximal flange, swelling carrot-shaped ( Fig. 212) (Lesser Antilles; northern South America) ...... testacea (Dallas)