Orthocephalus Fieber

Namyatova, Anna A. & Konstantinov, Fedor V., 2009, Revision of the genus Orthocephalus Fieber, 1858 (Hemiptera: Heteroptera: Miridae: Orthotylinae) 2316, Zootaxa 2316, pp. 1-118 : 5-8

Orthocephalus Fieber

Orthocephalus Fieber, 1858: 316 . Type species by subsequent designation ( Reuter, 1888: 411): Lygaeus brevis Panzer, 1798 .

Oraniella Reuter, 1894: 138 . Type species by subsequent designation ( Kirkaldy, 1906: 131): Oraniella tibialis Reuter, 1894 , NEW SYNONYMY.

Anapomella Putshkov, 1961: 25 . Type species by original designation: Anapomella arnoldii Putshkov, 1961 , NEW SYN- ONYMY.

DIAGNOSIS: Recognized by the following combination of characters: dorsum or at least pronotum impunctate, hemelytra rarely with indistinct punctation; dorsum smooth to distinctly rugose; head extended ventrally well below inferior margins of eyes, diameter of eye distinctly shorter than, or at least as long as, distance between eyes and apex of clypeus ( Fig. 20 A–F), head always more narrow than posterior margin of pronotum in macropterous males ( Fig. 22 A, G), with flat to moderately convex frons; eyes often only slightly bulging ( Fig. 20 A–C, F), sometimes somewhat protruding ( Fig. 20 D, E); antennal segment I short, always shorter than and rarely equal to length of head, with two mesial spine-like setae (except O. championi and O. rhyparopus ); dorsum covered with scalelike or flattened silver setae ( Figs. 22 A–F, 23 A–D) (but see discussion on O. solidus ), and with robust, bristlelike, or long erect simple setae at least on head and pronotum ( Figs. 22 A–E, H, 24 A- C); hind tarsal segment I at least two times as short as segment II, segment II somewhat longer than segment III; endosomal membrane of aedeagus typically with one, two, or three large spicules, sometimes without any armament (Figs. 7–9), ductus seminis short and wide, middle portion membranous with sclerotized ribs, and apical portion peculiarly bowl-shaped, strongly dilated, sclerotized, flattened dorsoventrally, and funnelshaped apically, secondary gonopore slit-like, deeply incised, with distinct sculpture predominantly distributed on strongly sclerotized ventral wall, dorsal wall weakly sclerotized, leaf-shaped, broadly rounded, and twice as long as ventral wall ( Fig. 5). The structure of the apical part of ductus seminis is considered crucial to the diagnosis of Orthocephalus .

Careful investigation of the genera Anapomella Putshkov, 1961 and Oraniella Reuter, 1894 allows us to conclude that they are congeneric with Orthocephalus . Orthocephalus is most similar to Dasyscytus Fieber, 1864 and Pachytomella Reuter, 1890 in the body proportions, impunctate or shallowly punctate dorsum, widened head, antennal segment I distinctly shorter than width of vertex, and dark brown to black coloration. Genital structures of some Pachytomella species are very similar to those of Orthocephalus . The monotypic genus Dasyscytus is separated from Orthocephalus by the following: the hemelytral membrane is clothed with simple setae, the absence of scalelike or flattened setae on dorsum, the uniformly pale coloration of hemelytra in males, antennal segments III and IV only slightly thinner than segment II, and the large, somewhat dilated, but distinctly non-funnel-shaped distal sclerotization of ductus seminis ( Fig. 6). Pachytomella differs from Orthocephalus in the bulging, laterally protruded eyes ( Fig. 20G), so that the head width of males is nearly equal to the basal width of the pronotum, the more gracile body in males, the vestiture composed only of exceptionally short simple setae, and the absence of flattened or scalelike setae ( Figs. 23E, F, 24D). Species of the genus Pachytomella show some variation in ductus seminis structure. The distal portion is always twosegmented, with more or less developed sclerotized ring at the base followed by a membranous area and apical sclerite bearing a slit-like, moderately sculptured opening of the secondary gonopore ( Fig. 6). The apical sclerite of the ductus seminis varies in shape from a nondilated, tube-like structure as in P. parallela , to a distinctly dilated, dorsoventrally flattened, triangular to bowl-shaped form reminiscent of that in Orthocephalus species , as in P. passerinii , P. phoenicea , P. doriae , and P. cursitans . However, the ductus seminis in all these species differs from those of Orthocephalus species in having two segments, with the distal portion separated from the basal portion by an entirely membranous region and the secondary gonopore not incised, moderately sculptured, and devoid of a large, broadly rounded outgrowth of the dorsal wall (compare lateral views on figs. 5 and 6). In O. proserpinae , the distal portion of the ductus seminis is comparatively long and not bowlshaped, only slightly dilated (fig. 5), but funnel-shaped apically, flattened dorsoventrally, and possessing all the other distinctive features of the genus. Structures of the female genitalia, specifically the simple vestibulum lateral to the vulva, and the simple posterior wall of the bursa copulatrix, were found to be of limited diagnostic value at the generic level in this group of genera.

Anapus Stål, 1858 , Schoenocoris Reuter, 1890 , and Platyporus Reuter, 1890 are similar to Orthocephalus in the presence of scalelike setae, but differ from this genus in the distinctly bulging eyes and frons, the long antennal segment I with numerous bristle-like setae, and the entirely different structure of ductus seminis, viz. the distal portion not dilated but tube-like and two-segmented, with a cup-shaped sclerotized apex separated from a sclerotized base by more or less entirely membranous section (fig. 6).

REDESCRIPTION: Male: Variable in size, elongate to ovoid, length 2.1–7.2. COLORATION (figs. 1–3): Body dark brown to black, often with pale brown, orange or yellowish areas; head dark brown to black, usually with pale brown or yellowish roundish spot or stripe along inner margin of each eye and rarely with additional medial spot anterior to these, with yellowish stripe along posterior margin of eye, and rarely with yellowish clypeus; coloration of antenna, labium, evaporatorium, legs, and hemelytra ranging from totally dark brown to almost entirely yellowish, membrane uniformly pale brown or sometimes with pale stripes and spots. SURFACE AND VESTITURE: Dorsum smooth or somewhat rugose, pronotum and scutellum impunctate, hemelytra rarely with shallow indistinct punctation. Vestiture variable, with four types of setae: (1) scalelike, apically acuminate silver setae usually covering dorsum, pleurites, and abdomen, rarely legs (figs. 22 A– C, E, 23 A, D), in some species scalelike setae absent; (2) flattened, although not scalelike, apically acuminate silver setae (figs. 22 D, F, 23 B, C), covering dorsum and pleurites in species lacking scales of the first type; (3) simple dark or pale setae, short and thin to contrastingly long and robust, bristle-like (figs. 22 H, 24 A–C), covering entire body surface; (4) rows of spinelike dark or pale setae on tibiae, a pair of similar setae on antennal segment I. Longitudinal ridges always strongly developed on setae of first type, typically absent or at least strongly obliterated on the second type of setae. STRUCTURE: Head transverse (figs. 20 A–F), with more or less distinct depression along hind margin of vertex; frons convex, rarely flattened; eye oval from lateral view (figs. 21 E, G, H) and roundish from anterior view (figs. 20 A–F), not protruding or slightly protruding laterally (figs. 20 A–F); mandibular and maxillary plates subquadrangular; antennal fossa located close to (fig. 20 B) or at a distance from (figs. 20 A, C–F) inferior margin of eye, antennal segment I as thick as segment II or only slightly thinner, shorter than vertex; segment II often cylindrical, sometimes incrassate; antennal segments III and IV thin, almost equal in length, together as long as antennal segment II; length of labium ranging from surpassing middle coxa to reaching genital segment; pronotum trapeziform with straight, broadly rounded to more or less carinate sides; posterior margin straight or concave; posterior angles of pronotum rounded (figs. 22 A, G); calli more or less distinct, from nearly flat to distinctly raised; mesoscutum usually partly exposed; evaporatorium of metathoracic scent gland elongate-oval, with distinctly elongated, caudally directed posterior angle (fig. 24 E); scutellum almost flat, hind femora of typical shape, rarely swollen; tarsal segment I approximately half as long as tarsal segment II, tarsal segment II and tarsal segment III almost equal in length; hemelytra macropterous, rarely brachypterous. GENITALIA (figs. 5, 7–13): Genital segment and parameres of typical Halticini shape—right paramere spoon-shaped, with pointed apex, left paramere Lshaped, with apical process as long as or longer than body of paramere, hooked at apex (figs. 10–13). Aedeagus: Ductus seminis with middle part membranous, with ribs, distal portion strongly sclerotized, bowl-shaped, strongly flattened dorsoventrally, secondary gonopore slit-like, with largely extended, leaf-shaped, weakly sclerotized dorsal wall and comparatively short, strongly sclerotized ventral wall; sculpture around secondary gonopore well developed, predominantly distributed on ventral wall (fig. 5); theca membranous, with sclerotized dorsal wall; endosoma voluminous, usually armed with two spicules of variable shape and size, sometimes with three spicules, single spicule, or devoid of any armament (figs. 7–9).

Female: Broadly oval, with more robust body than in male; length 2.4–5.9; COLORATION: As in male but often darker; hemelytra often dark brown to black, pale stripes on hemelytra narrower than in male. SUR- FACE AND VESTITURE: More rugose than male; vestiture as in male; scalelike and flattened silver setae, if present, more dense. STRUCTURE: Head and pronotum wider than in males and eyes shorter; hind femora more swollen than in males; usually brachypterous, hemelytra with corium and clavus fused, delimited by shallow claval suture; cuneus often delimited with shallow cuneal fracture, cuneal fracture sometimes indistinct, membrane absent, apex of hemelytra rounded or truncate; length ranging from reaching fourth abdominal segment to covering entire abdomen; hemelytra rarely macropterous, but more oval than in males. FEMALE GENITALIA (figs. 14–19): Dorsal labiate plate with well developed sclerotized rings of different shape and often with sclerites on medial margins (called “medial sclerites” in the present paper). (figs. 14–17). Posterior wall of bursa copulatrix with broad trapeziform sclerite and sometimes with pair of sclerites at sides of posterior margin (fig. 18 O. brevis ) or with single sclerite in middle of posterior margin (fig. 18 O. melas ). Trapeziform sclerite with anterior incision along midline, sometimes medially membranous (figs. 18–19), anterior angles of this sclerite often somewhat dentate. Vulva surrounded by a pair of sclerites, sometimes thin, strongly curved and encircling vulva, more often straight or somewhat curved, located lateral to vulva and not surrounding vulva (fig. 19).

HOSTS: Host-plant data are not available for most of the rare species. Widely distributed species are evidently polyphagous and were collected from plants of various families. Many species are associated with Asteraceae , but these associations are not highly species-specific. Some species were reported also from Apiaceae , Campanulaceae , Euphorbiaceae , Fabaceae , Fagaceae , Lamiaceae , Poaceae , and Rosaceae . Available data on hosts are summarized for each species. Nomenclature of plant names is given in accordance with the latest edition of Cherepanov’s catalogue ( Cherepanov, 1995).

DISCUSSION: Species of Orthocephalus are rather variable in appearance and genitalic structure. Our investigation showed that a workable diagnosis did not exist for the genus and there was no character which could be used to separate it from closely related genera, such as Anapomella Putshkov, 1961 , Oraniella Reuter, 1894 , and Pachytomella Curtis, 1842 . All characters previously used for delimitation of all these genera by Fieber (1858), Reuter (1891, 1894), Wagner (1974), Putshkov (1961), and Wagner and Weber (1965) were thoroughly evaluated.

Fieber (1858) described Orthocephalus as having the following distinguishing characters: the vertex is convex; the base of clypeus, antennal fossa, and inferior margin of eye are located at one level; the xyphus is triangular and keeled; the labium reaches the hind coxae; and the second segment of hind tarsus is longer than the third.

Reuter (1891) broadened the diagnosis and description for Orthocephalus , making both very similar to those given for Pachytomella . According to Reuter, the distinctive characters for Orthocephalus were the following: head vertical, often narrower than the base of pronotum; clypeus located lower than inferior margin of eyes; evaporatorium distinct; dorsum covered with long black setae and usually with scales as well; fore tibiae are straight, not curved; and the second segment of the hind tarsus is distinctly longer than the third.

Wagner and Weber (1965) and Wagner (1974) characterized Orthocephalus by the elongated body, macropterous male and brachypterous female, vertical head, presence of brownish spots near eyes, two or three rigid setae on antennal segment I, antennal segment IV shorter than III, and the first segment of hind tarsus twice as short as the second.

In the present study, only the shape of head, and the type of vestiture were found to be useful in distinguishing Orthocephalus from Pachytomella ; however, these characters do not separate Orthocephalus from Oraniella and Anapomella .

Reuter (1894) erected Oraniella to include two new Mediterranean species, O. tibialis and O. tristis . He distinguished his new genus from Orthocephalus by the small body size, long labium, reaching middle of abdomen, extremely short female hemelytra, eyes inclined backwards, swollen femora, and indistinct cuneus. Subsequently Wagner (1974) used the length of labium as a crucial character for distinguishing Oraniella from Orthocephalus .

The monotypic genus Anapomella was described by Putshkov (1961), who provided a comparison of this new genus with Pachytomella , Orthocephalus , and Oraniella . According to the original description, Anapomella differs from Orthocephalus and Pachytomella in the type of vestiture, swollen femora and weak sexual dimorphism. Putshkov also suggested that Anapomella occupies the intermediate position between Orthocephalus and Pachytomella in the shape of foretibia and the ratio of head width to length. According to him the foretibiae in Pachytomella are somewhat curved and those in Orthocephalus are straight and cylindrical, and the head width/length ratio is not more than 1.20–1.25 in O. bivittatus and O. medvedevi , 1.35–1.40 in Anapomella , and 1.40–1.55 in Pachytomella .

Our examination of available material indicates that the degree of sexual dimorphism, head width/length ratio, and the shape of foretibiae cannot be viewed as diagnostic. Three species currently assigned to Anapomella and Oraniella are closely related and differ from most Orthocephalus species by the swollen femora, long labium, and presence of scalelike setae on femora and tibia. However, these characters vary within Orthocephalus and we consider them of limited value at the generic level.

In particular, although hind femora in Anapomella and Oraniella are distinctly saltatorial, several species of Orthocephalus (for example O. minimus ) also possess comparatively short and thickened hind femora. The labium reaches the middle of the abdomen in Anapomella arnoldii and Oraniella tibialis , but reaches the middle coxae in most Orthocephalus species. Both Anapomella and Oraniella species have scalelike setae on the dorsum, pleurites, abdomen, femora, and tibiae (fig. 23 D), whereas about half of the Orthocephalus species have scalelike setae only on the dorsum (as in figs.22 A–C, E, 23 A), pleurites, and abdomen (though females of O. sefrensis possess the same pattern of vestiture as in Anapomella and Oraniella , e.g., having scales on the femora). The remaining Orthocephalus species have moderately flattened silver setae (as in figs. 22 D, F, 23 B, C) instead of scalelike setae (but see O. solidus ). Species of Pachytomella have neither scalelike setae nor flattened silver setae but are clothed with fine and contrastingly short pale setae (as in figs. 23 E, F, 24 D).

On the other hand, all species of Orthocephalus , Oraniella , and Anapomella are similar in the structure of male genitalia, particularly having the peculiar shape of the distal part of ductus seminis as discussed in the diagnosis, which is unique in the Halticini . Based on the above, the generic names Anapomella and Oraniella are synonymized with Orthocephalus (see also phylogenetic analysis).