Identification of Rhodopsalta species
Genus Rhodopsalta Dugdale, 1972
The genus Rhodopsalta includes the Redtailed Cicadas. That is, species characterised by alternating reddish-orange and black bands across the back of their abdomen.
The genus is in need of revision. Only the very succinct descriptions of Myers (1921) and Hudson (1936, 1950) are available at the species level. Hudson (1950) still provides the latest and most comprehensive treatment of Rhodopsalta species (then classified in the genus Melampsalta). Consequently, a list of diagnostic characters has been extracted from Hudson (1950) and the characters rephrased in order to write preliminary descriptions (see below) that are comparative between the three known species, with additional notes between square brackets []. A tentative identification table is also provided at the end of this webpage.
Remarks. When Dugdale (1972) created the genus Rhodopsalta, he listed only two species in it, R. cruentata and R. leptomera. Subsequently, Wise's (1977) New Zealand checklist and Duffels and Van der Laan's (1985) world catalogue recorded the species microdora under its original name Cicadetta microdora. Palma et al.'s (1989) list of primary types in the National Museum of New Zealand gave details of the primary type of Cicadetta microdora, with a note indicating the current name of this species should be Rhodopsalta cruentata; this suggests the two species may have been considered to be synonymous at some stage but it is still unclear whether such synonymy was ever published intentionally. On the other hand, more recent publications (e.g., Arensburger et al., 2004b; Simon, 2005) included 3 species in the genus Rhodopsalta, and Simon (2005) specifically included R. microdora as well as R. cruentata and R. leptomera. Consequently, until more serious revisionary work is done, Rhodopsalta is treated here as containing the 3 species listed by Simon (2005). It may be worth noting that Arensburger et al. (2004b) suggested the existence of an additional undescribed species.
Rhodopsalta cruentata (Fabricius, 1775) - Blood Redtail Cicada
Characteristics (from Hudson, 1950: 134). Body: length 14–21 mm; background colour brownish yellow or reddish with black markings, with distinct pale median stripe from tip of head to tip of abdomen [stripe varies from wide and complete to very narrow or incomplete]; overall silvery haircover more or less developed (less so than in R. leptomera). Mesosternum (underside of middle of thorax) almost entirely pale. Anterior wing: costa (thick front edge) [green or yellowish green, tinged with reddish orange towards tip] and other veins green [or yellowish]. Wingspan 41–44 mm. Abdomen: dorsal surface black in anterior third of remaining segments black with posterior margins distinctly red (especially towards sides). Genitalia (see Dugdale, 1972: 870).
Range. New Zealand: North Island (throughout), South Island (northern part; upper North Canterbury, Kaikoura, Marlborough Sounds, Northwest Nelson and upper West Coast Regions).
Habitat. Lowland (mostly)-subalpine; at lower elevations on various indigenous and introduced trees and shrubs, and on coastal dune grass; in beech forests and on shrubs in subalpine environments (e.g., North Island Central Volcanic Plateau).
External hyperlink.The 2010 Catalogue of New Zealand Auchenorrhyncha (more details on nomenclature, biology, distribution, and dispersal).
Rhodopsalta leptomera (Myers, 1921) - Sand Dune Redtail Cicada
Characteristics (from Hudson, 1950: 141). Body: length 16–23 mm; background colour pale brownish yellow with black markings, [usually] with indistinct pale median stripe from tip of head to tip of abdomen [stripe sometimes indistinct on head and thorax or indistinct throughout]; overall silvery haircover strongly developed (more so than in R. cruentata), to the extent of obscuring body markings. Mesosternum (underside of middle of thorax) black. Anterior wing: costa (thick front edge) and other veins orange-yellow. Wingspan 43–46 mm. Abdomen: dorsal surface black with posterior margins of segments faintly red, but overall appearance grey due to cover of silvery hairs closely pressed against surface.
Range. New Zealand: North Island (mostly the western coast; also North of Auckland, some eastern populations).
Habitat. Lowland, coastal; near the beach on sand dune vegetation (e.g., marram grass, native grass, Scirpus frondosus (low down in leaf axils)).
External hyperlink.The 2010 Catalogue of New Zealand Auchenorrhyncha (more details on nomenclature, biology, distribution, and dispersal).
Rhodopsalta microdora (Hudson, 1936) - Little Redtail Cicada
Characteristics (from Hudson, 1950: 132–133; females only). Body: [length about 14 mm]; background colour pale green [, yellowish green or reddish] with black markings, with apparently indistinct pale median stripe on abdomen [stripe distinct on head, usually absent on thorax, and absent or barely defined on abdomen]; overall silvery haircover barely developed. [Mesosternum almost entirely pale]. Anterior wing: costa (thick front edge) green tinged with orange-brown towards tip, other veins green. Wingspan 34–37 mm. Abdomen: dorsal surface dull orange-brown, with seven transverse black bands, broadest on midback [=dorsal surface black in anterior fourth or third, remaining segments black with posterior margins dull orange-brown, sometimes reddish]. Note: Hudson’s characters rephrased for easier comparison with R. cruentata and R. leptomera; characters not mentioned by Hudson are given between square brackets.
Identification notes. Hudson commented that this species is "immediately recognisable by its small size, slender build, pale-green colour, and apparent obsolescence of median stripe on abdomen." In New Zealand cicadas, females are on average larger than males. Consequently, males of R. microdora may be as small or even smaller than the two females described by Hudson, which would make this cicada the smallest of the three Rhodopsalta species.
Range (Simon, 2005). New Zealand: North Island ("central-eastern regions"), South Island ("east of the 'main divide' (Southern Alps) from the Wairau River Valley south"). Note: Described from Cape Kidnappers (North Island, Hawkes Bay Region).
Habitat. Lowland, coastal as well as inland. Note: No other data could be found in the literature.
External hyperlinks.The 2010 Catalogue of New Zealand Auchenorrhyncha (more details on nomenclature, biology, distribution, and dispersal) and the virtual collection of primary types of Hemiptera (photos of primary types).
| Tentative identification table (Rhodopsalta species). | |||
|---|---|---|---|
| cruentata | leptomera | microdora | |
| body length | >14 mm | > 14 mm | <= 14 mm , usually <14mm |
| wingspan | > 40 mm | > 40 mm | < 37 mm |
| background colour | brownish yellow or reddish with black markings | brownish yellow with black markings with abdomen appearing grey due to cover of silvery hairs closely pressed against surface | pale green with black markings |
| dorsal median white stripe | from tip of head to tip of abdomen; stripe varies from wide and complete to very narrow or incomplete | from tip of head to tip of abdomen, sometimes indistinct on head and thorax or indistinct throughout | distinct on head, usually absent on thorax, and absent or barely defined on abdomen |
| colour of costa | green or yellowish green, tinged with reddish orange towards tip | orange-yellow | green tinged with orange-brown towards tip |