A new species of Chucallis Tao (Hemiptera, Aphididae, Calaphidinae) from China

Abstract A new species in the aphid genus Chucallis Tao, Chucallis latusigladius Qiao, Jiang & Chen, sp. n. feeding on a species of bamboo, Indocalamus tessellatus (Munro) Keng f., is described. It differs from the only other known species in the genus by having remarkably large marginal processes on abdominal tergite IV. A key to species, morphological descriptions, distributional data and host plant information are provided. The type specimens studied are deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.


Introduction
The aphid genus Chucallis was erected by Tao (1964), based on Myzocallis bambusicola Takahashi, 1921 as the type species. The genus can be easily separated from related genera by having long, finger-like dorsal processes on the abdomen, especially marginal ones. Until now, only one species is known (Remaudière and Remaudière 1997). After identifying the specimens and checking the specimens of the type species, we found a new species, Chucallis latusigladius Qiao, Jiang & Chen, sp. n., which is described in this paper. It is different from the only other known species in the genus in having remarkably large marginal processes on abdominal tergite IV. It feeds on one species of bamboo, Indocalamus tessellatus (Munro) Keng f., and occurs in Zhejiang and Fujian, China.

Materials and methods
Aphid terminology generally follows Quednau (2003) and Qiao et al. (2005). The unit of measurements is millimeters (mm). Metrical data were listed in Table 1.  Tao: Tao 1990: 139;Zhang 1999: 227-228;Qiao et al. 2005: 184. Generic diagnosis. In alate viviparae, frontal tubercle not developed. Head without epicranial suture, clypeus without any processes. Antennae 6-segmented, processus terminalis slightly longer than base of the segment. Head and thorax without any dorsal processes. Abdominal tergites with dorsal spinal processes and developed marginal processes. Dorsal setae of body long and pointed, thick or fine. Rostrum short and stout. Wing veins without black borders. Fore coxae distinctly expanded, mid-and hind coxae normal. First tarsal chaetotaxy: 5, 5, 5. Siphunculi truncated, slightly longer than their basal diameters. Cauda knob-shaped. Anal plate bilobed. Gonapophyses fused. In embryos, dorsal setae of body thick and long, pointed or stout. Dorsum of head with 2 pairs of anterior and 2 pairs of posterior setae. Thoracic tergites each with 1 pair of spinal and 1 pair of marginal setae, respectively. Abdominal tergites I-VII each with 1 pair of spinal and 1 pair of marginal setae, respectively, and spinal setae on tergites III, V and VII slightly displaced pleurally; tergite VIII with 2 dorsal setae. Siphunculi visible.
Biology. The species colonize the undersides of the leaves of their host plants. Matsumura (Quednau 2003), but the alatae differ from those genera in having the clypeus without a nose-like processus (Subtakecallis and Takecallis: the clypeus with a noselike processus), and some abdominal tergites with long, finger-like, seta-bearing spinal and marginal processes, the marginal ones on tergite IV being especially large (Subtakecallis and Takecallis: some abdominal tergites with small processes, not longer than their basal width).  (Tao 1990).
Mounted specimens. Head and thorax pale brown, dorsal spinal processes, marginal processes and seta-bearing processes brown; antennal segment I pale brown, antennal segments II-VI unpigmented; apex of rostrum brown; femora, tibiae and tarsi pale brown; siphunculi, cauda, anal plate and genital plate pale brown; wing veins pale and unbordered, basal and inner margins of pterostigma with dark fuscous forming a conspicuous crescent-shaped mark (Fig. 19); the other parts of specimens pale. Posterior margin of pronotum with short wrinkles; distal 1/3 of antennal segment III and segments IV-VI with sparse imbrications, middle of inner margin of segment I slightly swollen (Figs. 2, 21); distal 1/4 of tibiae with spinules, tarsi with spinulose short imbrications; dorsal spinal and marginal processes with sparse spinules or spinulose short stripes; cauda, anal plate and genital plate with sparse spinulose short stripes. Dorsal setae of body thick and pointed, long or short. Head with 1 pair of cephalic setae, 2 pairs of antennal tubercular setae and 2 pairs of posterior dorsal setae between eyes (Fig. 1); pronotum with 2 pairs of spinal and 1 pair of posterior marginal setae; abdominal tergite I with 1 pair of spinal and 1 pair of marginal setae, each on dorsal processes; tergite VIII with 5 or 6 setae, occasionally 7 or 8, 1 pair of them on dorsal spinal processes. Length of cephalic setae, marginal setae on abdominal tergite I and dorsal setae on tergite VIII 0.038-0.058, 0.029-0.058 and 0.029-0.058, respectively, all 1.50-3.00 times as long as basal width of antennal segment III.
Thorax. Dorsum of thorax without any processes. Legs slender. Fore coxae distinctly expanded, mid-and hind coxae normal. Hind femur 0.98-1.09 times as long as antennal segment III, hind tibia 0.50-0.59 times as long as body. Setae on legs short, stiff and pointed, apex of tibiae with 3 peg-shaped setae (Fig. 26), distinct differ from other setae. Length of setae on hind tibia 1.25-1.67 times as long as mid-width of the segment. First tarsal chaetotaxy: 5, 5, 5. Wing veins pale without bordered; forewing with radial sector absent or with basal half indistinct; basal and inner margins of pterostigma thickly marked with brown fuscous (Figs. 11,19); hind wings with two oblique veins.
Embryo (in alate viviparous female). Dorsal setae of body thick, long and capitate at apex, with distinct basal processes (Fig. 17). Setal pattern (Fig. 18): dorsum of head with 2 pairs of anterior and 2 pairs of posterior setae; pro-, meso-and metanotum each with 1 pair of spinal and 1 pair of marginal setae, respectively; abdominal tergites I-VII each with 1 pair of spinal and 1 pair of marginal setae, respectively; spinal setae on tergites III, V and VII slightly displaced pleurally; tergite VIII with 2 spinal setae. Siphunculi visible.
First instar nymph. Body oval, head and thorax yellow green, and abdomen dark green in life (Fig. 39). Mounted specimens pale, with brown dorsal processes (Fig.  31). Body 0.80-1.06 long and 0.50-0.62 wide. Antennae 4-segmented, segment III 0.208-0.213 long, basal diameter of the segment 0.0144-0.0192. Abdominal tergites I-VII each with 1 pair of spinal and 1 pair of marginal processes, respectively; spinal processes on tergites III, V and VII slightly displaced pleurally; tergite VIII with 2 spinal processes. Each processus with one seta, thick, long and capitate at apex, same as setae of embryos. Spinal processes on tergite II 0.017-0.022 long, with setae 0.095-0.110 long; marginal processes on tergite IV 0.05-0.06 long. Siphunculi truncated. Cauda triangle, with blunt round apex. Anal plate semicircle.
Second instar nymph. Body 1.02-1.27 long and 0.75-0.94 wide (Figs. 32, 40). Antennae 5-segmented, segment III 0.20-0.30 long, basal diameter of the segment 0.0144-0.0192. Spinal processes on tergite II 0.018-0.038 long, with setae 0.087-0.136 long; marginal processes on tergite IV 0.12-0.16 long. The other characteristics similar to first instar nymph. Taxonomic notes. The new species is similar to the type species C. bambusicola (Takahashi), but differs in colour in life and morphology by the characters given in the key.
Host plant. Indocalamus tessellatus. Biology. It colonizes the underside of the leaves of the host plant (Fig. 35).