Typophyllum egregium Hebard 1924

Braun, Holger, 2015, Little walking leaves from southeast Ecuador: biology and taxonomy of Typophyllum species (Orthoptera, Tettigoniidae, Pterochrozinae), Zootaxa 4012 (1), pp. 1-32 : 3-5

Typophyllum egregium Hebard 1924

( Figs. 1 , 2 , 3 , 4 )

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:5513

Hebard 1924: 219, Vignon 1931: 126, Beier 1960: 359, Braun 2002: 66 ( Typophyllum sp. 2, “Berg-Spaziergehblättlein“), Braun 2008: 216 ( Fig. 1 : male), 220, Chamorro-Rengifo et al. 2014: 595.

Examined specimens. Female holotype, Ecuador, Tungurahua, 2130 m [7000 ft], Academy of Natural Sciences, Philadelphia (pencil drawings December 2003); 13 males and 7 females from four localities in Parque Nacional Podocarpus and its periphery, leg. H. Braun between 4 October 1997 and 17 September 1999 (currently in collection of author): Cordillera del Consuelo: male cbt002s01 (sound recording) 2200 m; male cbt002s13 (sound recording), 2300 m; female cbt002s14, 2410 m; female cbt002s15, 2840 m; male cbt002s17 (sound recording), 2830 m; male cbt002s21 (sound recording), 2500-3000 m; El Tiro: male cbt002s19, 2880 m; Cajanuma around 2750 m: male cbt002s02 (sound recording), male cbt002s03 (sound recording), male cbt002s04, male cbt002s05, male cbt002s06, male cbt002s07, female cbt002s08, female cbt002s09, female cbt002s10, female cbt002s11, male cbt002s18 (sound recording); Quebrada Honda 2480 m: male cbt002s20 (sound recording), [the female nymphs cbt002s12 and cbt002s16 belong to Typophyllum onkiosternum sp. nov. described below]

Notes. “The type of this striking species is unique” wrote Hebard (1924) in the original description, and this seems to have remained so up to the present. The new-found females are very similar to this specimen, and taking into consideration the intraspecific morphological variation of the genus Typophyllum , they most probably are conspecific. The volcano Tungurahua (5023 m), where the type was found at around 2100 m, is about 300 km north of the investigation area and also part of the eastern Andean cordillera. Hopefully this population has survived the recent volcanic activity starting in October 1999, with several subsequent eruptions, and still high activity with emission of ash in September 2014 (according to online newspaper articles in El Comercio and El Universo, Ecuador).

Description. The internal and external tympanal chamber walls of the foretibia are equally developed and not expanded, and also the bases of the hind tibia are not expanded, placing this species in the first of the four groups of Vignon (1925a). Figures 1 , 2 and 4 show the small males and large females, which do not show really distinctive characters, apart from the shape of the sexually dimorphic tegmina. However, there is considerable variation, especially in females, where the distal half of the anal margin can be undulated or uniform ( Fig. 3 ), and the tip can be elongated or not ( Fig. 4 ). The male’s right tegmen has a transparent speculum ( Fig. 4 E). Hindwings are small, of about two-thirds the length of the tegmina. As in other Typophyllum species nearly all body parts can have small tubercles and tiny granules or are wrinkled to individually varying degree. Hairs are fairly sparse and mostly very short. Some females have a tiny knob at the tip of the maxillary palp. The pronotal disc is widened posteriorly, more pronouncedly in males, with a tiny notch in the hind margin. The prosternum has short delicate spines (slightly shorter than diameter of tip of maxillary palp); the mesosternal and the metasternal spines are slightly longer and less delicate. Often there are small medial lappets on second and third abdominal tergites (probably vestiges of moss camouflage in nymphs).

Coloration. Highly variable ( Fig. 1 ). Most frequently uniformly medium or dark brown, sometimes uniformly light green ( Fig. 4 A), and sometimes two colours mixed: green with dark brown or reddish brown portions, light brown with dark brown markings, or dark brown with very light legs and antennae.

Measurements. Tegmen length in males 13–15 mm and in females 22.5–24.5 mm (in holotype 32 mm), hind femora in males 12–14 mm and in females 16–17.5 mm (in holotype 17 mm), antennae in males up to 45 mm, in females slightly longer.

Acoustic behaviour. The males’ calling song ( Fig. 19 A) consists of isolated “double zips”, partly in the audio range and fairly loud (in contrast to pure-tone low ultrasound songs of most other Typophyllum species). Each of the two syllables is preceded by a very low pulse which corresponds probably the opening stroke of the tegmina. These syllables are each resolved into about 30 (20–35 depending on the individual) initially crescending transient impulses corresponding to the individual tooth-scraper impacts. These rapidly decaying impulses result in a still moderately narrow spectrum with a peak at 18 kHz. While in the natural habitat calls are separated by pauses of several minutes, after seven days in confinement one male was calling like a lunatic in his cage with up to six calls within 45 seconds at 23°C (at the upper limit of the distribution range at 3000 m the medium temperature at midnight is 8°C and lowest temperatures measured with field recordings were 9.5–11.5°C). Calling is restricted to night, with very sporadic calls on gloomy afternoons within the clouds.

Mating behaviour. Males and females kept together in cages showed a number of instances of the piggyback behaviour where the male spends one to mostly several days riding on one side of the female’s tegmina before copulation. The small male usually sits perpendicular on the tegmen surface with his body axis more or less parallel to the main veins (Sc/R) and the head directed to the wing tip. Once a male rode for one day on the female, the subsequent copula lasted five hours, then the individuals separated. Another time a different male spent five days riding on the same female before they separated without copula. Some other time three males climbed within two hours onto a female (one on each side of the wings and the third on top—surely an artefact of crowded conditions); after three days the last mounted male mated and stayed in contact with the female via the spermatophore for at least 10 hours, then the forth night the second male mated, and in the subsequent night the third (and first to have mounted), where the copula lasted at least 3.5 hours. In yet another instance copula occurred after the male rode for two days on the female. Females often walked around with their riders and unlike the males they ingested food. The observed copulations occurred mostly late at night and lasted sometimes to noon the following day. Size of the spermatophores was approximately 7 mm x 3 mm x 3 mm and the females began to feed on them immediately after copula. After successful mating the individuals always separated.

Distribution. In this species the numerous acoustic records allowed a complete assessment of its altitudinal distribution range in the investigated area ( Fig. 20 A). It occurs in a wide range from apparently 1500 m to 3000 m on both slopes of the cordillera, with the lowest observation at the interandean western side at 2750 m due to the lower limit of survey there. It cannot be completely excluded that the song was not confused with some other species with a double-zip audio call at lower elevations; the lowest record of an insect was at 2120 m. T. egregium was found in the valleys of Río San Francisco and Río Sabanilla, at El Tiro, Cajanuma and in Quebrada Honda. The uppermost living individuals inhabit small fragments of elfin forest in wind-protected vales. Along with the type locality the geographical distribution comprises the eastern Andean cordillera at least from central Ecuador to the border with Peru.

Figures

FIGURE 1. Typophyllum egregium: four males with different coloration, photos staged during day (specimens cbt 002 s 13, - s 02, - s 20 and - s 04).

FIGURE 2. Typophyllum egregium: female and male habitus (specimens cbt 002 s 09, light green morph with apically rounded tegmina, and cbt 002 s 01, brown), note difference in size and tegmen venation.

FIGURE 3. Typophyllum egregium: left tegmina of females (left column) and males (right), note variation in shape and venation (female specimens: cbt 002 s 10, - s 14, - s 11, males: cbt 002 s 02, - s 15, - s 06).

FIGURE 4. Typophyllum egregium: A. green female (specimen cbt 002 s 09), B, C. brown female (- s 10), D, E. brown male (- s 03); in live females ovipositor usually concealed by tegmina; note transparent mirror in right tegmen of male (all photos to same scale).

FIGURE 19. Oscillograms and linear spectrograms of calling songs of four Typophyllum species: A. T. egregium, complete call (field recording, 9.5 ºC, specimen cbt 002 s 21); B. T. onkiosternum sp. nov., one double pulse of longer sequence (cage, 18 ºC, cbt 004 s 01); C. T. morrisi sp. nov., one pulse and below complete call, here consisting of three pulse groups (cage, 23 ºC, cbt 003 s 01); D. T. erosifolium one pulse and below seven double pulses from continuous calling (cage, 20 ºC, cbt 001 s 01); all recordings made at night.

FIGURE 20. Altitudinal distribution of A. Typophyllum egregium and B. T. erosifolium; investigated gradient from 1000 – 3400 m divided in 100 - m intervals, acoustic records based on one survey per locality, the two individuals of T. erosifolium between 1200 m and 1300 m were found at sites where no calling could be detected (Bombuscaro and Alto Nangaritza).