Tytthus piceus (Osborn & Drake) Henry, Thomas J., 2012

Henry, Thomas J., 2012, Revision of the Plant Bug Genus Tytthus (Hemiptera, Heteroptera, Miridae, Phylinae), ZooKeys 220, pp. 1-114 : 59-61

Tytthus piceus (Osborn & Drake) comb. n. Figs 35 –3771–78167– 170

Isoproba picea Osborn and Drake 1915: 533 (orig. descrip.); Carvalho 1952: 72 (as type); Carvalho 1958(2): 201 (cat.); Cassis 1984: 165 (subfam. note); Schuh 1995: 498 (cat.).

Tytthus hondurensis Carvalho 1984: 203 (orig. descrip.); Schuh 1995: 248 (cat.). syn. n.

Diagnosis.

This species, known from macropterous males and females (Figs 35, 36) and brachypterous females (Fig. 37), is distinguished by the bulbous black head, the black pronotum and scutellum having a distinct glaucous sheen, the raised finely punctate pronotal calli, the pale translucent-brown hemelytra, and the pale yellow to white first antennal segment with a narrow black ring at the base.

Tytthus piceus keys out with Tytthus pallidus , n. sp but can be distinguished by the bulbous head, especially in males, the shorter antennal segment I that is only subequal to the interocular width, and the distinct calli that are covered in a glaucous sheen.

Description.

Male (n = 10; holotype in parentheses) (Figs 35, 71, 72): Length to apex of hemelytron 2.35-2.50 mm (2.70 mm), length to base of cuneus 1.70-1.75 mm (1.89 mm), width across hemelytra 0.62-0.66 mm (wings folded). Head: Length 0.34-0.37 mm (0.35 mm), width across eyes 0.51-0.54 mm (0.50 mm), interocular width 0.24-0.26 mm (0.26 mm). Labium: Length 1.07-1.14 mm (imbedded in glue). Antenna: Segment I, length 0.26-0.27 mm (antennae missing); II, 0.98-1.02 mm; III, 0.50-0.56 mm; IV, 0.40-0.50 mm. Pronotum: Length 0.32-0.34 mm (0.32 mm), basal width 0.59-0.61 mm (0.59 mm).

Coloration: Head (Figs 73-75): Shiny black; eyes black. Labium: Segment I fuscous to black, apex paler yellowish brown, tinged with red or reddish brown in some specimens; segments II–IV pale yellowish brown, apex of segment IV fuscous. Antenna: Segment I pale yellowish brown to white, with a narrow black ring at base; segments II–IV uniformly black. Pronotum, mesoscutum, and scutellum: Shiny black, with a distinct glaucous sheen. Hemelytron: Uniformly smoky brown, slightly darker brown on clavus. Ostiolar evaporative area (Fig. 76): Dark reddish brown to fuscous. Ventral surface: Thorax dark brown or fuscous; abdomen in males dark brown, sometimes paler ventrally, genital capsule fuscous to black; abdomen in females yellowish green to pale brown, with broad lateral margins and ovipositor fuscous to black. Legs: Uniformly yellowish brown, inner face of pro- and mesofemora and outer face of metafemur usually with a narrow reddish line; claw (Fig. 78).

Structure, texture, and vestiture: Head: Impunctate, round or bulbous in both sexes, slightly wider than long; with scattered, long, erect setae on frons and vertex and a few short, erect setae on eyes. Labium: Extending to abdominal segment II or III. Pronotum: Trapeziform, narrowest anteriorly, lateral margins weakly concave, flaring to humeral angles; impunctate, except for a few scattered punctures on distinctly swollen calli. Mesoscutum: Broadly exposed. Scutellum: Equilateral, weakly convex, rising just above level of hemelytra. Hemelytron: Translucent, subparallel; in macropterous males and females (Figs 35, 36) cuneus longer than wide at base, membrane fully developed, extending well beyond apex of abdomen; in brachypterous females (Fig. 37) lateral margins slightly more rounded than macropters, cuneus reduced to about as wide as long, membrane greatly reduced, extending only to the sixth or seventh abdominal tergite, exposing apex of abdomen.

Male genitalia: Left paramere (Fig. 167): Mitt-shaped; right arm long, wide, apically blunt; left arm shorter, apically pointed. Right paramere (Fig. 168): Elongate oval. Endosoma (Fig. 169): Strongly C-shaped, apically blunt. Phallotheca (Fig. 170): Relatively slender, apically acute.

Macropterous female (n = 10) (Fig. 36): Length to apex of hemelytron 2.60-2.85 mm, length to base of cuneus 1.85-2.05 mm, width across hemelytra 0.70-0.83 mm. Head: Length 0.35-0.40 mm, width across eyes 0.54-0.58 mm, interocular width 0.27-0.29 mm. Labium: Length 1.18-1.22 mm, extending to near base of ovipositor. Antenna: Segment I, length 0.26 mm; II, 0.85-0.93 mm; III, 0.51-0.53 mm; IV, 0.43-0.45 mm. Pronotum: Length 0.34-0.37 mm, basal width 0.69-0.70 mm.

Brachypterous female (n = 3) (Fig. 37): Length to apex of hemelytron 1.80-1.90 mm; length to base of cuneus 1.55-1.60 mm; length to apex of abdomen 2.20-2.40 mm; width across hemelytra 0.64-0.70 mm. Head: Length 0.35-0.40 mm, width across eyes 0.54-0.58 mm, interocular width 0.29 mm. Labium: Length 1.10-1.14 mm, extending to abdominal segment II. Antenna: Segment I, length 0.26-0.29 mm; II, 0.82-9.94 mm; III, 0.51-.56 mm; IV, 0.43-0.45 mm. Pronotum: Length 0.29-0.34 mm, basal width 0.51-0.59 mm.

Host.

Adults and nymphs have been taken in large numbers on switch grass, Panicum virgatum L. cv ‘Alamo’ [ Poaceae ], infested with Delphacidae (A. G. Wheeler, pers. comm.).

Distribution.

This species was described and known previously only from Guatemala (as Isoproba picea ) and Honduras (as Tytthus hondurensis ). Colombia, Costa Rica, Mexico, Panama, and the United States (Florida, Maryland, and South Carolina) represent new country records and considerable range extensions.

Discussion.

Specimens of Tytthus piceus from Colombia, Costa Rica, Honduras, Mexico, and Panama represent an expected distribution for a Central American species, but the recent detection of it in Florida, Maryland, and South Carolina in the United States is somewhat of a mystery. The eastern United States is relatively well collected, so it seems unlikely that early workers overlooked this unusual bug, given that other obscure species of the genus with similar habits, such as Tytthus vagus (Knight) and the tiny Tytthus alboornatus (Knight), have been discovered. The most logical explanation is that Isoproba piceus has been inadvertently introduced relatively recently and moved around on ornamental grasses, such the one A. G. Wheeler found serving as a host in the South Carolina Botanical Gardens.

I have examined the holotypes of Tytthus hondurensis and Tytthus piceus and find them conspecific.

Type material examined.

Holotype ♂ (of Isoproba picea ) (00162336) (OSU): GUATEMALA: Pt. Barios: 3/3/05 [J. S. Hine coll., as per Osborn and Drake, 1915], Herbert Osborn collection. Holotype ♂ (of Tytthus hondurensis ) (00162205) (USNM): HONDURAS:Atlantida: Lancetilla, Aug 1701, Stadelmann.

Other specimens examined.

COLOMBIA:Cundinamarca: Sasaima, 4.96638°N, 76.4375°W, 1221 m, 28 Aug 1965, J. A. Ramos, 1 ♀ (00161785) (USNM). COSTA RICA:Cartago: Pejibaye, 24 Mar 1987 - 25 Mar 1987, W. E. Steiner, 1 ♀ (00161786) (USNM). Puntarenas: El Palmar, Jan 1962, J. O. Harrison, 2 ♂♂ (00161449 - 00161450) (USNM). MEXICO: San Luis Potosi: Huichihayan, 25 Sept. 1938, L. J. Lipovsky, 1 ♂ (UK).

PANAMA: Cerro Jefe, 12 Mar. 1969, R. L. Fischer, elev. 2000 ft., 1 ♀ (00166062) (AMNH). UNITED STATES:Florida:Miami-Dade Co.: Coral Gables, Matheson Hammock, 10 May 1997, Vince Golia, sweeping, 1 ♀ (00161829) (USNM). Maryland:Howard Co.: Howard Co. field, 18 Oct 1961, collector unknown, red clover ( Fabaceae ), 1 ♂ (00161827) (USNM). South Carolina:Pickens Co.: South Carolina Botanical Garden, Clemson, 28 Aug 2004, A. G. Wheeler, Jr., Panicum virgatum , 1 ♀ (00161813) ( Poaceae ), 5 ♂♂ (00161814 - 00161818), 7 ♀♀ (00161819 - 00161825), 1 nymph (00161826) (USNM); 31 Jul 2005, A. G. Wheeler, Jr., Panicum virgatum ( Poaceae ), 11 ♂♂ (00161787 - 00161797), 15 ♀♀ (00161798 - 00161812) (USNM).