Extraordinary Endemism: The Nearctic Leafhoppers ofGloridonusBall andBallanaDeLong (Hemiptera: Cicadellidae)

Abstract

Leafhopper species assigned to Ballana DeLong and Gloridonus Ball include nearly 15% of all endemic leafhoppers reported from arid regions of the southwestern USA and 29% of the leafhoppers considered to be endemic to California. Ballana is revised and subsumed within Gloridonus, the whole comprising 83 valid species: 10 belonging to the nominate subgenus Gloridonus, 56 restricted to the subgenus Ballana stat.nov. including 1 subspecies (B. brevidens curta DeLong) raised to species rank, leaving 15 species in the subgenus Laterana and 2 species in Gloridellus subg. nov. There are 42 new synonymies from among DeLong's species of Ballana described in 1937 and 1964 (quira = B. adversa DeLong, 1937; volsella = B. apta DeLong, 1964; letura, insula = B. angula DeLong, 1937; diversa, omani, paridens = B. arma DeLong, 1937; fatuita = Thamnotettix atridorsum Van Duzee, 1894; tiaja = B. calcea DeLong, 1937; bicornis, profusa = B. calipera DeLong, 1937; coarcta = B. callida DeLong, 1937; rara = Ballana [brevidens] curta DeLong, 1964; firma = B. delea DeLong, 1937; aleta = T. dissimilata Ball, 1910; clara = B. dola DeLong, 1964; mira = B. effusa DeLong, 1964; attenuata = B. filamenta DeLong, 1937; remissa = B. hebea DeLong, 1937; simplex, telora = B. indens DeLong, 1937; delta = B. nigridens DeLong, 1937; aperta, calcara = B. occidentalis DeLong, 1937; curvidens, orleta = B. polica DeLong, 1937; datuna = B. recurvata DeLong, 1937; mana = B. seca DeLong, 1937; sera = B. mera DeLong, 1937; parallela = B. spinosa DeLong, 1937; dira, extrana, repa = T. titusi Ball, 1910; youngi = T. ursina Ball, 1910; cerea = B. valga DeLong, 1937; prava = T. vastula Ball, 1910; antlera, aris = B. velosa DeLong, 1937; dupla = T. verutus Van Duzee, 1925; absenta = T. [atridorsum] vetula Ball, 1910; delicata, pleura = T. [titusi] vivata Ball, 1910). Nine of DeLong's species are reduced to subspecies rank (brevidens, chelatus, defectus, exterus, luxuria, merus, tolara, transeus, valgus), leaving 68 new combinations (all the valid species previously in Ballana except for gerula Ball). These include 10 new species and also 3 new subspecies: Gloridonus ajo, G. eburatus, G. effusus diablo, G. forfex, G. forfex yosemite, G. jacumba, G. pulcher, G. xerophilus and G. yolo from California, G. xyston and G. abruptus conicus from the state of Washington plus G. baja and G. quintini from Mexico. Regional endemism is strongest in California (63 species). As in its small sister-genus Pasadenus Ball, the greatest number of species of Gloridonus is confined to the Santa Rosa Mountains of San Diego County and very few species have been found southwards into adjacent Mexico; but Gloridonus also has many additional species farther north to Oregon and east to Arizona, and a few even from southern British Columbia to Wisconsin. This high degree of southwestern endemism appears to be the result of microevolutionary processes (similar to those in the equally diverse but more widespread grass-feeding leafhopper genus Athysanella Baker) acting on a fauna restricted to a geographically and botanically diverse area, with monophagy or oligophagy as the driving force behind speciation. Hosts of Gloridonus are reported for 45 leafhopper species mainly from genera of Asteraceae, but also in Boraginaceae, Caprifoliaceae, Ericaceae, Fabaceae and Nyctaginaceae.