Description of a new species of Metabemisia Takahashi, 1963 from China (Hemiptera, Aleyrodidae)

Abstract A new whitefly species, Metabemisia leguminosa sp. n., collected from an undetermined leguminous herb is described from Wuzhishan Mountain, Hainan Island, China. The puparium of the new species differs from that of all other Metabemisia species by the presence of 4–5 rows of very small distinct papillae along the margin, the absence of the first abdominal seta, and the indistinct thoracic tracheal pores. An identification key to the worldwide species of Metabemisia is provided.


Introduction
The genus Metabemisia (Hemiptera: Aleyrodidae) was established by Takahashi (1963) with M. distylii Takahashi as its type species by monotypy. Only three species have hitherto been placed in this genus. Takahashi (1963) described M. distylii from Japan on Distylium racemosum. Mound (1967) described M. filicis from Scotland on Dryopteris sp., Nephrolepis sp. and Davallia sp.; from England on Pteris togoensis or Cyclosorus dentate, and Ko et al. (1998) recorded the same species from Taiwan (China) on Tectaria decurrens. Martin (2001) described M. palawana from Philippines on Lastreopsis sp.
A faunal survey of Aleyrodidae was conducted in some nature reserves of Hainan Island in May 2012 as the Aleyrodidae fauna in these areas had not been previously investigated in detail. Puparia of an undescribed species of this genus were collected from Wuzhishan Mountain, this being the first record of the genus from Mainland China.

Material and methods
The puparia of the new species were collected from an undetermined leguminous herb found on Wuzhishan Mountain, 18°51'N, 109°39'E, 561 m, Hainan Island, China on 18 May, 2012. The puparia were mounted on glass slides following the method suggested by Martin (1987), as compared with other methodologies such as the method given by Hodgesa and Evans (2005) and Dubey and David (2012), the steps are almost same except slight differences. The terminology for morphological structures follows Bink-Moenen (1983), Martin (1985) and Gill (1990). The measurements were made through measuring 9 specimens including the holotype, using a LEICA MZAPO stereo-microscope. The Scanning Electron Microscope (SEM) images were taken using Philips XL30-Environmental Scanning Electron Microscope at 20 kV/EHT and 80 Pa between 157 to 1258 times magnification. The detail steps of SEM study following Wang et al. (2014).
The holotype is deposited in the Insect Collection of Yangzhou University (YZU). A paratype will be deposited in each of the following institutions: Natural History Museum (BMNH), London, UK; Zoological Survey of India (ZSI), Kolkata, India; the remainder of the paratypes are currently deposited in Insect Collection of Yangzhou University and Shanghai Entomological Museum, Chinese Academy of Sciences (SHEM).

Diagnosis.
Puparium elliptical, with a single row of submarginal setae, M. distylii and M. filicis bear ten pairs of submarginal setae while M. palawana bears 14 pairs. Vasiform orifice elongate-cordate to triangular, much longer than wide, the trapezoidal operculum occupying about half of orifice (Takahashi 1963;Martin and Camus 2001). This genus resembles Parabemisia Takahashi in the shape of puparium and the presence of a row of submarginal setae, but can be distinguished by the lingula wanting lateral tubercles and in the presence of caudal tracheal cleft. It also resembles Neomaskellia Quaintance & Baker, but differ in the characters of vasiform orifice. Paratypes: Fifteen paratypes, same data as the holotype, 15 puparia on 15 slides, (WZS-NO.2-4: BMNH-1, ZSI-2); (WZS-NO.5-16: SHEM-2, YZU-10). 17 dry puparia on leguminous leaves with above collection data available at YZU.
Diagnosis. This species is characterized by the submarginal area with ten pairs of subequal longsetae (Figs 2, 6), about 74.6-93.6µm,the presence of 4-5 rows of very small distinct pore along the margin (Figs 1, 5), the absence of the first abdominal setae, and the thoracic tracheal pores being indistinct, the submedian depressions are particularly distinct on abdominal segment I-VI (Fig. 7), vasiform orifice triangular (Figs 4,8), longer than wide, lingula with a pair of apical setae (Figs 4, 8).
Venter. Thoracic tracheal folds and pores not discernible. Ventral abdominal setae placed on either side of anterior angles of vasiform orifice, finely pointed and 7-9 µm long, 67 µm apart. Adhesive pads present at apex of legs.
Third instar (Figs 10-11). yellowish, elliptical, about 514-558µm long, 289-303µm wide, the other morphological characteristics are basically identical with the puparia except the vasiform orifice region. The operculum (Fig. 11) protruded in the central part, about 18.6-20.3 µm long, 34.9-36.7 µm wide, and covering about half  Biology. Specimens were found in clusters of 5-8 per leaf, centrally on the under surface of leaves. No evident signs of damage have been noted on the host plant. No parasitoids were obtained from the puparia. No ant attendance was observed.
Etymology. The species name was derived from the family name of the host plant; adjective.

Remarks
The new species resembles M. filicis by the ten pairs of submarginal setae, and by having a pair of sub-median depressions present on the abdominal and thoracic segments. However, in the new species the sub-median depressions are present on abdominal segments I-VI while in M. filicis on abdominal segments I-VII (Mound 1967). In addition the new species differs from M. filicis by the absence of the first abdominal setae, the indistinct thoracic tracheal pores andthe presence of 4-5 rows of very small distinct papillae along the margin. It also resembles the species of Neomaskellia Quaintance & Baker, 1913, N. andropogonis Corbett, 1926 andN. bergii (Signoret, 1868), but differs from them by the number of submarginal setae and the shape of vasiform orifice (Martin 1987