A new species of Aleuromarginatus Corbett, 1935 with a key and checklist of Chinese species (Hemiptera, Aleyrodidae)

Abstract A new whitefly species, Aleuromarginatus dielsianae Wang & Xu, sp. n. collected from Millettia dielsiana Harms (Rosales: Fabaceae) in Jiangshan (28°40'N, 118°40'E, 512 m) and Xinchang (29°22'N, 120°46'E, 308 m), Zhejiang, China, is described and illustrated. This new species is characterized by the dark brown lateral margin area and a pair of longitudinal furrows extending from the cephalothorax to the vasiform orifice. The submargin has an elongate-oval fold at the base of each marginal tooth and with 3-4 rows of irregular shaped papillae, nine pairs submedian setae and 13 pairs submarginal setae. Thoracic and caudal tracheal folds and pores discernible. An identification key and checklist of species of Aleuromarginatus known from China are provided.


Introduction
The genus Aleuromarginatus (Hemiptera: Aleyrodidae) was established by Corbett (1935) with A. tephrosiae Corbett as the type species by monotypy. Aleuromarginatus is very distinct; based on the special characteristics of the puparium it unlikely to be confused with other whitefly genera. It is an Old World genus, recorded from the Afrotropical, Palearctic, Oriental, and Australasian regions. Only 14 species of this genus have been described, almost all of them are known only from leguminous plants (Fabaceae) (Bink-Moenen 1983;Cohic 1968Cohic , 1969Corbett 1935a;David 1976David , 1988David and Subramaniam 1976;Jesudasan and David 1991;Ko et al. 1995;Martin 1985Martin , 1999Martin and Mound 2007;Mound and Halsey 1978;Takahashi 1955).
This genus was unknown from East Asian region until Ko et al. (1995) described Aleuromarginatus shihmensensis Ko on Millettia seiculata from Taiwan. In addition, A. thirumurthiensis David is known to occur in Taiwan (Chiun-Cheng Ko personal collection) and Wang et al. (2016) recorded A. corbettiaformis Martin from Hainan Island of China. In this paper, the fourth species of Aleuromarginatus from China is described.

Material and methods
Puparia of the new species were collected from Millettia dielsiana Harms (Rosales: Fabaceae) in Shuangxikou village, 28°40'N, 118°40'E, 512 m, Jiangshan and Jingling town, 29°22'N, 120°46'E, 308 m, Xinchang, Zhejiang, China. The puparia were mounted following the method suggested by Dubey and David (2012). The terminology for morphological structures follows Bink-Moenen (1983), Martin (1985) and Gill (1990). The habitus images were taken using the digital camera Canon IXUS 105 and LEICA M125 stereo-microscope (Leica, Wetzlar, Germany) attached with a LEICA DFC290 (Leica, Wetzlar, Germany). Puparial measurements and microphotographs were taken using a Zeiss (Carl Zeiss, Gottingen, Germany) from ZAFU. The scanning electron microscope images were taken by Hitachi TM-1000 Scanning Electron Microscope (Hitachi, Japan) from Center of Electron Microscopy, Zhejiang University (Life Sciences Division). Adobe Photoshop software was used to make small adjustments and to assemble the plates. The holotype is deposited in the Insect Collection of Zhejiang Agriculture & Forestry University, Lin'an, China (ZAFU).
Diagnosis. Puparia elongate to broadly oval, often slightly indented anteriorly and posteriorly and/ or at thoracic tracheal openings at margin (Martin 1999); margin with two rows of teeth and surrounded by a waxy palisade and fringe of wax-hairs; submarginal area not separated from dorsal disc. Dorsal with a subdorsal and submedian row of short setae including the cephalic, first and eighth abdominal setae; vasiform orifice cordate, operculum filling about half of orifice, lingula knobbed, exposed; caudal furrow faint (Jesudasan and David 1991;Ko et al. 1995). This genus resembles Aleurotrachelus in the two-teethed margin, and resembles Crenidorsum with the submedial furrow or papillae, but can be distinguished by the characters of the vasiform orifice and the absence of spine-like setae on the medial region of the dorsum. Diagnosis. This species is characterized by the dark brown margin area (Figs 4,11,12), in life with a pair of longitudinal submedian lines (Fig. 4) and microscopically with a pair of longitudinal submedian furrows (Figs 5,7,8,11) from cephalothorax to the vasiform orifice. Submargin with an elongate-oval fold at the base of each marginal tooth and with 3-4 rows of irregularly shape papillae (Figs 9,12). Nine pairs submedian setae (Fig. 14), minute, blunt -one pair of cephalic setae (cs), two pairs of thoracic setae (ts), six pairs of abdominal segment I and III-VI, VIII (as1, 3-6, 8); 13 pairs submarginal setae (sms) (Fig. 14) -three cephalic pairs, five thoracic pairs, one abdominal pair, and four posterior pairs. Vasiform orifice cordate (Figs 10, 13, 16); operculum broadly trapezoidal, covering nearly half the orifice; lingula exposed, setose, knobbed. Paired posterior marginal setae present while anterior marginal setae absent. Thoracic and caudal tracheal folds and pores discernible (Figs 6, 14).

Aleuromarginatus dielsianae
Description. Puparium. Puparia have highly characteristic secretions in the form of a broad, laterally directed, white fringe on each side of the body, the fringe about 0.24-0.29 mm long; body light yellowish, transparent, margin dark brown; two longitudinal pigmented bands encompassing the submedian zone on either side of the body lines from cephalothorax to vasiform orifice; elliptical, 1.08-1.12 mm long, 0.75-0.82 µm wide, broadest at the abdominal segments I region. The presence of a colony can be easily ascertained by the dense bumps on the upper surface of the leaves caused by the puparia which embed themselves into the under surface of leaves, pushing the top surface of the leaf upward (Fig. 1).    Figures 11-13. Aleuromarginatus dielsianae sp. n., slide mounted specimen. 11 puparium, dorsal view 12 margin 13 vasiform orifice, operculum and lingula. (Figs 4,5,7,8,11) extending from the cephalic region to the vasiform orifice, the longitudinal furrows consist of some short longitudinal furrows. Submargin with an elongate-oval fold at the base of each marginal tooth and with 3-4 rows of irregular shape papillae (Figs 9, 12). Nine pairs submedian setae, minute, blunt -one pair of cephalic setae (cs), two pairs of thoracic setae (ts2, 3) which are on the 2 nd and 3 rd thoracic segments; six pairs of abdominal setae, one pair on each segments I and III-VI, VIII (as 1, 3-6, 8). Thirteen pairs submarginal setae (sms) -3 cephalic pairs, 5 thoracic pairs, 1 abdomen pair and 4 posterior pairs. The submedian setae and submarginal setae each arising from a small tubercle and are subequal in length, about 6.1-6.7 µm. Longitudinal and transverse molting sutures reaching the anterior and lateral margin, respectively. The transverse molting suture slightly protruding forming a transverse ridge (Fig. 7). Thorax  Vasiform orifice (Figs 10, 13, 16) cordate, longer than wide, 65.5-68.3 µm long, 60.2-62.3 µm wide; operculum broadly trapezoidal, covering nearly half the orifice, 29.5-34.8 µm long, 39.2-41.2 µm wide. Lingula exposed, setose, knobbed, 9.1-12.2 µm long, 13.6-16.4 µm wide, with a pair of apical setae, about 7.4 µm in length.
Venter. Thoracic and caudal tracheal folds and pores discernible (Fig. 6). Ventral abdominal setae placed on either side of anterior angles of vasiform orifice, finely pointed and 5.7-7.8 µm long, 53.1 µm apart. Antenna slender, long, extending slightly beyond the prothoracic spiracular furrow but not reaching base of mesothoracic leg.

Distribution. China (Zhejiang).
Biology. Specimens were found on the leaves in colonies from 20 -60 individuals, distributed throughout the under surface of leaves (Fig. 2). No parasitoids were obtained from the puparia and no ants were observed attending the whiteflies.
Etymology. The species name takes its name of host plant Millettia dielsiana Harms.
Remarks. The new species resembles A. millettiae Cohic but differs in that the longitudinal furrows extend from the submendian region of the cephalic to the vasiform orifice while they are only present on the abdomen for A. millettiae and differs in the number and postion of the submarginal setae. The new species also resembles A. kallarensis David & Subramaniam but can be easily distinguished by the shape and the size of the puparia.