Scutellera Lamarck, 1801

Rédei, Dávid & Tsai, Jing-Fu, 2022, A revision of Scutellera (Hemiptera: Heteroptera: Scutelleridae), Zootaxa 5092 (1), pp. 1-40 : 2-5

Scutellera Lamarck, 1801

Scutellera Lamarck, 1801: 293 . Type species by monotypy: Cimex nobilis (non Linnaeus, 1763): Fabricius (1775: 697), misidentification (= Tectocoris perplexa Westwood, 1837 ).

Scutellera: Latreille ([1804a]: 163) (diagnosis, review), Latreille ([1804b]: 176) (diagnosis, review), Latreille (1807: 112) (diagnosis, review), Latreille (1810: 254) (diagnosis), Leach (1814: 35) (diagnosis), Lamarck (1816: 490) (redescription), Latreille (1819: 441) (diagnosis, review), Le Peletier & Serville (1828: 409) (redescription, review), Laporte ([1833]: 67, 70) (in key, redescription), Burmeister (1835: 395) (redescription, review), White (1839: 537) (type species, identity), Blanchard (1840: 157) (redescription, review), Agassiz (1843: 18) (listed), Dallas (1851: 4, 18) (in key, listed), Dohrn (1859: 2) (catalogue), Vollenhoven (1863: 11) (redescription, fauna of Dutch East Indies), Stål ([1865]: 33) (in key), Mayr (1866: 17, 22) (in key, listed), Walker (1867: 15) (listed), Stål (1871: 616) (diagnostic characters), Stål (1873: 9, 14) (in key, synopsis), Atkinson (1887: 161) (redescription, fauna of India), Lethierry & Severin (1893: 21) (catalogue), Kirkaldy (1900: 263) (listed, type species), Distant (1902: 42, 50) (in key, redescription, distribution, fauna of British India, Ceylon and Burma), Schouteden (1904: 15, 22) (in key, redescription, catalogue), Kirkaldy (1909: 289, 303) (catalogue, distribution), Distant (1918: 116) (listed), Hoffmann (1932a: 10) (listed), Yang (1934: 238, 256) (in key, diagnosis, fauna of China), Hoffmann (1935: 181) (listed), Tang (1935: 281) (catalogue, China), Ishihara (1947: 64) (listed), Leston (1952: 22) (listed), Stichel (1961: 728) (catalogue, Palaearctic), Stichel (1962: 208) (catalogue, Palaearctic), Fujiyama (1967: 398) (listed), Hsiao & Cheng (1977: 55, 60) (in key, fauna of China and Taiwan), Ahmad et al. (1979: 28, 31, 35) (in key, listed), Ahmad (1980: 124) (distribution in Pakistan), Datta et al. (1985: 20) (listed), Chen (1987: 125) (in key), Chakraborty et al. (1994: 473) (listed), Ghosh et al. (1994: 495, 496, 498) (listed, in key), Javahery et al. (2000: 491) (economic importance), Cassis & Vanags (2006: 286) (listed), Göllner-Scheiding (2006: 200) (catalogue, Palaearctic), Biswas & Bal (2007: 304) (in key), Ghosh (2008: 412, 417) (in key, diagnosis, species of economic importance in India), Biswas & Bal (2010: 240) (in key), Tsai et al. (2011: 68, 151) (in key, redescription, distribution, bionomics, fauna of Taiwan), Takai & Ishikawa (2012: 461) (redescription, fauna of Japan), Parveen et al. (2014: 254) (morphology), Parveen & Gaur (2015: 169, 170, 182) (listed, in key, diagnosis), Ishikawa (2016: 492) (catalogue, Japan), Cai & Cui (2017: 622, 635) (in key, diagnosis, fauna of Henan).

Calliphara (non Germar, 1839) (misidentification): Amyot & Serville (1843: 30) (redescription), Kirkaldy (1903: 232) (listed), Beier (1937: 2190) (listed).

Diagnosis. The specialized metathoracic scent gland ostiole (provided with a long and strongly widened, almost semicircular peritreme, evaporatorium strongly reduced) ( Fig. 19 : arrow; see also Fig. 12 ) is diagnostic for Scutellera . Other characters useful for recognizing this genus are the elongate oval body ( Figs. 1–3, 5, 6, 8, 9 , 11–13, 15, 16 , 18–23 ) covered by rather long, dense, erect to semierect pilosity, the presence of a wide and deep transverse furrow in the middle of the pronotum, and the long median furrow on the abdominal venter (extending to about the base of ventrite VII); these character states are also found in the closely related Brachyaulax Stål, 1871 , although the median furrow is only distinct on ventrites II–III in the latter.

Redescription. A redescription of the genus by Tsai et al. (2011) was based on S. nepalensis and S. perplexa . The transfer of S. spilogastra into Scutellera necessitates a revised redescription, as provided below.

Body medium to large (about 15–25 mm), elongate oval, moderately convex dorsally and ventrally; dorsal outline of body distinctly excised between base of scutellum and base of pronotum in lateral view ( Figs. 2 , 12 ). Body surface and vestiture. Dorsum with strong metallic lustre, sometimes with dull to subshining black spots; venter dull with large metallic spots; body and legs covered by dense, erect to semierect pubescence, smooth, with very small and fine, densely and evenly distributed, uniform punctures, head, pronotal calli, and base of scutellum usually more finely or indistinctly punctured, calli bordered by large, coarse punctures anteriorly and posteriorly; scape and basipedicellite with very few, scattered hairs, distipedicellite and flagellum with short and dense pilosity.

Head stout, 1.1–1.15 times as wide as its median length, 1.3–1.4 times (♂, ♀) as wide as interocular distance, convex, moderately declivous; lateral margin deeply emarginate anteriad to eyes, obtuse; clypeus slightly surpassing mandibular plates; mandibular plates rounded anteriorly; buccula unarmed; eyes relatively small, moderately protruding laterally; ocelli small, situated slightly posteriad to posterior margin of eye, relatively far from eye. Antenna five-segmented, apex of scape far remote from apex of head, basipedicellite much shorter than distipedicellite; scape and pedicellite cylindrical, basi- and distiflagellum flattened. Labium reaching from about base of abdomen to posterior margin of ventrite IV.

Pronotum. Anterior margin with impressed collar; calli distinct, fused medially, demarcated by a wide and deep transverse furrow posteriorly, cicatrices distinct; lateral margin nearly straight or slightly concave, narrowly carinate; humeral angle rounded; posterior margin nearly straight; posterolateral angle angulate. Scutellum wide, usually leaving only extreme margin of abdomen, base of exocorium and extreme base of endocorium exposed; with an indistinct, obscurely demarcated basal tumescence; rather strongly tapering towards apex posteriad of middle; apically broadly truncate. Membrane not or only narrowly exposed beyond apex of scutellum at rest. Thoracic pleura and sterna. Anterior explanate part of proepisternum weakly projecting anteriad; pterothoracic sternum with rather deep median furrow; metathoracic scent gland ostiole provided with a long and strongly widened, almost semicircular peritreme occupying almost all the metepisternum, its anterior margin nearly straight, posterior margin widely convex, with a shallow furrow running along posterior margin ( Fig.19 : arrow; see also Fig. 12 ); evaporatorium reduced, present only as narrow bands anteriad and posteriad of peritreme, not extending to mesopleuron (see also Tsai et al. 2011: 16, fig. 15 and Parveen et al. 2014: 240, fig. 2G and 254, fig. 19). Legs short; femora thick, unarmed; dorsal surface of tibiae with a wide longitudinal furrow.

Pregenital abdomen with a median longitudinal furrow extending to about base of ventrite VII; lateral margin obtuse; posterolateral angles of ventrites II–VI not produced, those of segment VII produced into a pair of conical, apically pointed processes; opening of dorsal abdominal scent glands of segment III far remote from lateral margin of abdominal tergites, situated about halfway between opening of those of segment IV and lateral margin of tergite IV.

External male genitalia. Genital capsule ( Figs. 30, 34, 38 ) narrowed posteriad, with a pair of minute submedian denticles on its posterior margin; dorsal setal patches continuous medially, band-like, narrowly bordering dorsal sinus; ventral setal patches extensive, situated on area of ventral infolding surrounding cuplike sclerite. Paramere ( Figs. 31–33, 35–37, 39–41 ) fully sclerotized, lacking desclerotized neck, stem elongate and columnar, crown short and hooked, a lateral, apically blunt flange provided with setae present. Phallus ( Figs. 42–52 ) symmetrical; phallotheca with a pair of callose thickenings dorsolaterally; conjunctiva with two pairs of processes (second and third pairs of the groundplan, cf. Tsai et al. 2011), second pair (cp-II) subdivided into cp-II 1 (lobe-like, of lateral position, at least partly sclerotized) and cp-II 2 (of mesal position, enclosed by cp-II 1, greatly membranous, with a sharp, sclerotized process apically), third pair (cp-III) heavily sclerotized, of various length and shape; aedeagus s. str. short, S-shaped, apex truncate; endophallic reservoir elongate oval, with double chamber, endophallic duct of two lumina system; aedeagal conducting tube very short, stout, constricted at middle, closely adhered to ventral angulate concavity of aedeagus s. str.

External female genitalia. Ovipositor plates posterior, almost vertical ( Figs. 53–55, 57–59, 61–63 ); laterotergites IX obliquely directed, fused valvifers IX partly exposed, with an obtuse median longitudinal keel. Gynatrium with a pair of long anterolateral pouches; ring sclerite long, far surpassing apex of fecundation canal, approaching apex of anterolateral pouch (frequently thin, inconspicuous,difficult to trace); a pair of small, transverse sclerites, occasionally fused along midline, present posteriad of spermathecal opening; fecundation canal forming a long and narrow, rodlike sclerite broadened or bifurcate distally, provided with a deep median furrow ( Figs. 65, 67, 69 ). Spermatheca with distal duct somewhat shorter and narrower than proximal duct; dilation with wall regularly, obliquely fluted externally, thick, sclerotized, inner surface provided with several thin, lamellate projections projecting into the inner lumen, invaginations of proximal and distal spermathecal ducts simple, apical receptacle ( Figs. 66, 68, 70 ) strongly elongate, with a globose apex.

Distribution and diversity. The genus is endemic to Indomalaya, and it occurs all over the region, also entering the Wallacea marginally ( Figs. 71, 72 ). It contains three described species.

Phylogenetic considerations. Scutellera and Brachyaulax share a number of skeletal characters mentioned in the diagnosis. The genitalia of both sexes are also highly similar, including a similar articulatory apparatus (particulary the sclerotized part of the erection pump), the phallotheca being provided with a pair of callose thickenings dorsolaterally, the similar shape of the conjunctival processes (both cp-II and cp-III) and the aedeagal complex in the male, and the presence of a median longitudinal carina on the fused valvifers IX, the elongate fecundation canal with a pair of apical projections, and the similar spermathecal dilation in the female (cf. Tsai et al. 2011). These morphological similarities likely indicate a close phylogenetic relationship, probably a sister relationship, between these two genera.

Scutellera (together with Brachyaulax ) is a highly specialized genus of Scutellerini, exhibiting several putative apomorphies within the subfamily. Due to its specialized morphology the polarity of several characters within the genus is difficult to determine. The laterally emarginate genital capsules ( Figs. 24, 25 , 30 vs. 28, 29, 38), similar shape of the conjunctival processes (particularly the lobe-like, externally partly sclerotized cp-II 1) ( Figs. 42, 43 vs. 46, 47), enlarged laterotergites VIII ( Figs. 53–55 vs. 61–63), the similar shape of fused valvifers IX ( Figs. 56 vs. 64), and the presence of a single transverse sclerite of the gynatrium posteriorad the opening of of spermathecal opening ( Figs. 65 vs. 69) are apparently shared characters between S. nepalensis and S. spilogastra , but it is difficult to establish whether they are synapomorphies or symplesiomorphies. The problem cannot be solved without examining a larger sample of Scutellerini with cladistic methods.

Remarks. Several authors in the early 19th century ( Latreille [1804a], [1804b], 1807, 1810, 1819, Leach 1814, Le Peletier & Serville 1828, Laporte [1833], Burmeister 1835, Blanchard 1840, etc.) used this generic name in a broad sense, in a way highly different from the current usage (sometimes also including various non-scutellerid pentatomoids with enlarged scutellum). Scutellera of Westwood (1837: 3), Germar (1839: 132) and Amyot & Serville (1843: 27) did not contain the type species (whilst all of them listed it under different genera), whilst the definitions of Scutellera provided by Hahn (1833: 172) and Schiødte (1843: 295) conflict with the type species and evidently correspond with Graphosoma Laporte, [1833] (Pentatomidae) and Tectocoris Hahn, 1834 , respectively; accordingly they must be considered as misidentifications of the genus.

Key to the species of Scutellera

1 (4) Body elongate, 2.3–2.4 times as long as its greatest width, scutellum 1.7–1.8 times as long as its greatest width; pronotum and thoracic pleura with extensive orange or red markings, peritreme red; femora red, with metallic blue-green annulus apically ( Figs. 1–3 , 11–13, 15, 16 , 18–23 )........................................................................ 2

2 (3) Dorsum with extensive, confluent markings, spots of scutellum invariably united into broad transverse fasciae ( Figs. 1, 2 , 11, 12, 15 ); lateral margin of genital capsule deeply emarginate ( Figs. 24, 25 , 30 : arrow) (♂); lateral portions of laterotergites VIII forming a pair of strongly protruding, rounded, lobe-like projections ( Figs. 53–55 : arrow), laterotergites IX relatively large, elongate, broadly separated in rest ( Figs. 53, 54 : lt 9) (♀) (Sub-Himalayan belt, South China, Indo-China, Taiwan, Ryūkyū Archipelago, Malay Archipelago)........................................ Scutellera nepalensis (Westwood, 1837)

3 (2) Dorsum with reduced markings composed at most of a narrow median vitta and isolated paired submedian spots which are never confluent ( Figs. 18, 20 ), but frequently without any markings ( Fig. 22 ); lateral margin of genital capsule not emarginate ( Figs. 26, 27 , 34 ) (♂); lateral portions of laterotergites VIII flat, not protruding posteriad, laterotergites IX smaller and shorter, more rounded, closely approaching each other or adjacent in rest ( Figs. 57–59 ) (♀) ( Indian Subcontinent, Indo-China , South China).............................................................. Scutellera perplexa (Westwood, 1837)

4 (1) Body distinctly broader, about 2.1–2.15 times as long as its greatest width, scutellum 1.35–1.45 times as long as its greatest width; pronotum and thoracic pleura without orange or red markings, peritreme black; femora nearly uniformly metallic bluegreen ( Figs. 5, 6, 8, 9 ) (southern India, Sri Lanka)............................. Scutellera spilogastra ( Walker, 1867)

Figures

FIGURES 18–23. Scutellera perplexa (Westwood, 1837). Figs. 18, 19, a female from Thailand: Nong Hoi (RMNH); Figs. 20, 21, a male from India: Himachal Pradesh, Sadhupul, near Simla (SEHU); Figs. 22, 23, a female from Sri Lanka: Uppuveli (RMNH). Dorsal (Figs. 18, 20, 22) and vental (Figs. 19, 21, 23) views. Scales in mm.

FIGURES 11–17. Lectotypes of Calliphara amethystina Germar, 1839 and Scutellera lanius Stål, 1854 and their labels. Fig. 11, C. amethystina, dorsal view; Fig. 12, same, lateral view; Fig. 13, same, ventral view; Fig. 14, same, labels; Fig. 15, S. lanius, dorsal view; Fig. 16, same, ventral view; Fig. 17, labels. Scales in mm. © ZMHB (Figs. 11–14), © NHRS, courtesy of G. Lindberg (Figs. 15–17).

FIGURES 1–10. Lectotypes of Tectocoris nepalensis Westwood, 1837, Callidea spilogastra Walker, 1867, and Scutellera brevirostris Breddin, 1909, with their labels. Figs. 1, T. nepalensis, dorsal view; Fig. 2, same, lateral view; Fig. 3, same, ventral view; Fig. 4, same, labels; Fig. 5, C. spilogastra, dorsal view; Fig. 6, same, ventral view; Fig. 7, same, labels; Fig. 8, S. brevirostris, dorsal view; Fig. 9, same, ventral view; Fig. 10, same, labels. Scales in mm. © OXUM (Figs. 1–4), © BMNH (Figs. 5–7), © SDEI (Figs. 8–10).

FIGURES 30–41. Scutellera spp., external male genitalia. Figs. 30–33, S. nepalensis (Westwood, 1837); Figs. 34–37, S. perplexa (Westwood, 1837); Figs. 38–41, S. spilogastra (Walker, 1867). Genital capsule, dorsal view (Figs. 30, 34, 38); right paramere, three different aspects (Figs. 31–33, 35–37, 39–41). Abbreviations: dsp = dorsal setal patch; mp = median projection of cuplike sclerite; vsp = ventral setal patch. Scales in mm. Figs. 30–33 from Tsai et al. (2011).

FIGURES 42–47. Scutellera spp., phallus (in repose). Figs. 42, 43, S. nepalensis (Westwood, 1837); Figs. 44, 45, S. perplexa (Westwood, 1837); Figs. 46, 47, S. spilogastra (Walker, 1867). Left lateral view (Figs. 42, 44, 46); posteroventral view (Figs. 43, 45, 47).Abbreviations: aed = aedeagus s. str.; cp-II 1, cp-II 2 = lobes of second conjunctival process; cp-III = third conjunctival process. Arrows in Figs. 42, 44 and 46 show aspects of Figs. 43, 45 and 47, respectively. Scales in mm. Figs. 42–43 after Tsai et al. (2011).

FIGURES 48–52. Scutellera spp., phallus. Figs. 4, S. nepalensis (Westwood, 1837), distal portion, ventral view; Fig. 49, S. perplexa (Westwood, 1837), inflated, lateral view; Fig. 50, same, posteroventral view; Fig. 51, same, distal portion, ventral view; Fig. 52, S. spilogastra (Walker, 1867), distal portion, ventral view. Abbreviations as in Figs. 42 and 43. Arrow in Figs. 49 shows aspect of Fig. 50. Scales in mm. Fig. 48 after Tsai et al. (2011).

FIGURES 53–64. Scutellera spp., female terminalia and ovipositor. Figs. 53–56, S. nepalensis (Westwood, 1837); Figs. 57–60, S. perplexa (Westwood, 1837); Figs. 61–64, S. spilogastra (Walker, 1867). Terminalia, posterior view (Figs. 53, 57, 61); same, posterodorsal view (Figs. 54, 58, 62); same, ventral view (Figs. 55, 59, 63); ovipositor and sternum X, posterior view. Abbreviations: ga = gonangulum; lt8, lt9 = laterotergites VIII, IX; = laterotergite IX; s10 = sternum X; t8 = tergite VIII; va8, va9 = valvulae VIII, IX; vf8, vf9 = valvifers VIII, IX. Scales in mm.

FIGURES 65–70. Scutellera spp., ectodermal genital tract of female. Figs. 65, 66, S. nepalensis (Westwood, 1837); Figs. 67,

FIGURES 71–72. Geographical distribution of Scutellera spp. Fig. 71: S. perplexa (Westwood, 1837). Fig. 72: Circles = S. nepalensis nepalensis (Westwood, 1837); squares = S. nepalensis amethystina (Germar, 1839); triangles = S. spilogastra (Walker, 1867). Solid markers represent specimens examined during the present study, empty markers unverified literature data.

FIGURES 24–29. Scutellera spp., terminalia of males. Figs. 24, 25, S. nepalensis (Westwood, 1837); Figs. 26, 27, S. perplexa (Westwood, 1837); Figs. 28, 29, S. spilogastra (Walker, 1867). Lateral (Figs. 24, 26, 28) and ventral (Figs. 25, 27, 29) views. Abbreviations: fw = fore wing; gc = genital capsule; sc = scutellum. Scales in mm.