Scaphytopiini Oman, 1943

Zahniser, James N. & Dietrich, Chris H., 2013, A review of the tribes of Deltocephalinae (Hemiptera: Auchenorrhyncha: Cicadellidae), European Journal of Taxonomy 45, pp. 1-211 : 152-155

Scaphytopiini Oman, 1943

Fig. 48

Type genus: Scaphytopius Ball, 1931 .

Diagnosis

Scaphytopiini are small to medium sized usually brownish, or sometimes black, yellow, or greenish leafhoppers, sometimes with irrorate markings and often with reflexed costal veins on the forewing. They can be identified by the anteriorly produced and pointed head, gena not incised laterally and visible behind eyes in dorsal view, frontoclypeus elongate, reflexed costal veins on the forewing, valve large, and connective broad, W - or U -shaped, and without or with a short stem.

Description

HEAD. Head narrower than pronotum; often produced and pointed anteriorly. Discal portion of crown glabrous with radial or longitudinal striae. Anterior margin of head angulate; texture shagreen, subcarinate, or with transverse striae. Frontoclypeus elongate; texture shagreen. Clypellus widening apically; apex following or slightly surpassing normal curve of gena. Lorum narrower, subequal to, or wider than clypellus near base. Antennal bases near middle or posteroventral (lower) corners of eyes. Antennae short, less than 1.5 x width of head. Gena broad; not incised laterally; visible behind eyes in dorsal view; with fine erect seta beside laterofrontal suture. Antennal ledges absent. Ocelli present; close to eyes; on anterior margin of head.

THORAX. Pronotum lateral margin carinate; lateral margin shorter than basal width of eye.

WINGS. Forewing macropterous; appendix restricted to anal margin; with 3 anteapical cells; veins not raised; with numerous reflexed costal veins; A1-A2 crossvein absent or present; apical venation not highly reticulate.

LEGS. Profemur with AM1 seta only; intercalary row with one row of five or more fine setae; row AV with short, stout setae or with relatively long macrosetae. Protibia dorsal surface rounded, convex. Metafemur apex macrosetae 2+2+1. Metatarsomere I not expanded apically; plantar setae simple, tapered.

MALE GENITALIA. Valve large; parabolically shaped; articulated with pygofer and subgenital plates; lateral margin short, articulating with pygofer at a point. Pygofer dorsoapical margin not strongly incised or incised to near mid-length; basolateral membranous cleft present; macrosetae well differentiated into several rows; without processes. Subgenital plates free from each other, articulated with valve; without macrosetae or with macrosetae uniseriate laterally. Style elongate; broadly bilobed basally, median anterior lobe pronounced. Basal processes of the aedeagus/connective often present, articulated to connective or near base of aedeagus. Aedeagus with single shaft and gonopore, or rarely ( Ascius ) divided near apex, with two gonopores. Connective anterior arms widely divergent, broadly W - or U -shaped, or somewhat divergent, Y - or U -shaped; stem usually absent; articulated with aedeagus or aedeagus dissociated from connective and attached only by thin membrane. Segment X sclerotized.

FEMALE GENITALIA. Pygofer with numerous macrosetae. Ovipositor not protruding far beyond pygofer apex. First valvula convex, dorsal sculpturing pattern strigate, concatenate, reticulate, or imbricate (with overlapping scales); sculpturing reaching dorsal margin; without distinctly delimited ventroapical sculpturing. Second valvula abruptly broadened medially or subapically or broad, gradually tapered; without dorsal median tooth; teeth on apical 1/3 or more; teeth small, regularly or irregularly shaped.

Geography and ecology

Distribution: Nearctic and Neotropical regions. Host plants are herbaceous and woody dicots. Scaphytopius (Cloanthanus) acutus (Say, 1830) is a vector of alfalfa witches’ broom, eastern and western X-diseases of peach, little cherry, soybean bud proliferation, clover phyllody, and western strain of North American aster yellows. S. (Convelinus) irroratus (Van Duzee, 1910) vectors the western strain of North American aster yellows. S. (Cloanthanus) magdalensis (Provancher, 1889) transmits blueberry stunt. S. (Convelinus) fuliginosus (Osborn, 1923) is a vector of machismo disease of legumes in Mexico and South America. S. (Convelinus) nitridus (DeLong, 1943) is a vector of western X-disease of stonefruits and celery in North America.

Remarks

Scaphytopiini contains 3 genera and 183 species. Based on phylogenetic analyses, the tribe as previously delimited ( Oman et al. 1990, Webb & Godoy 1993, Dmitriev 2002) was polyphyletic. Representatives of Japananus , Nesothamnus Linnavuori, 1959 , Proceps Mulsant & Rey, 1855 , Stymphalus Stål, 1866 and 2 representatives of Scaphytopius were included in analyses and the genera were found in different areas of the tree in most analyses. There was strong support for the branch including the two Scaphytopius species, but its relationship to other Deltocephalinae was poorly resolved. In Bayesian and ML analyses, Scaphytopius was resolved within a clade including the athysanine genus Eutettix and 3 others (PP=0.98). Japananus appears to be related to Opsiini , which is consistent with its bifurcate aedeagus. Ascius also has a bifurcate aedeagus, but it is retained in Scaphytopiini because it shares the numerous distinct reflexed costal veins and the widely separated anterior arms of the connective with Scaphytopius , along with the produced head and broad gena. Nesothamnus was often resolved near Idioceromimus Dietrich & Rakitov, 2002 in our analyses. Proceps is grouped with Cicadulini with strong branch support. Stymphalus , which is placed here in the new tribe Vartini , usually grouped with an undescribed genus from Thailand (DEL 112) and some Mukariini.

The characters formerly used to define the tribe, the produced head and the gena not incised laterally and visible behind the eye in dorsal view, appear to have arisen independently multiple times in Deltocephalinae and are therefore not reliable characters on their own at the tribal level. The tribe is interpreted here to contain only three genera from the New World.

Selected references

Hepner (1947), Oman (1949), Linnavuori (1959), Webb & Godoy (1993).

Included genera

Ascius DeLong, 1943

Scaphytopius Ball, 1931

Tenuarus DeLong, 1944

Figures

Fig. 48. Scaphytopiini. Scaphytopius acutus (Say, 1830). A–I. Standard views (see Material & Methods). G. Connective and style shown with connective processes. J. Lateral view of connective, style and connective processes.