Eriophyoid mites (Acari, Eriophyoidea) associated with tea plants, with descriptions of a new genus and two new species

Abstract A new genus and two new species of mites in the family Eriophyidae, Theaphyes rapaneae gen. n. and sp. n. which is found on the type host Rapanea neriifolia (Sieb. et Zucc.) Mez (Myrsinaceae) and Paracaphyllisa theacea sp. n., are described and illustrated. They are vagrants on the tea plant Camellia sinensis (L.) Kuntze and no apparent symptoms were detected. A key to the eriophyoid mites including thirteen species associated with tea plants all over the world is provided.


Introduction
Tea plants (Camellia) are perennial evergreen plants in the family Theaceae. They constitute a highly diverse taxon, presently composed of approximately 625 species (The Plant List on-line database 2013), distributed especially in tropical and subtropical areas. Some of these plant species are of extreme socio-economic importance.
Eriophyoid mites (Acari: Prostigmata) have a worldwide distribution. Eriophyoidea is a large mite superfamily with more than 4,000 described species (Zhang et al. 2011). They are strictly phytophagous, many of them can have the pest status in agricultural systems and are considered the second most economically important group of mite plant pests (Lindquist et al. 1996a). Nearly 80% have been reported on a single host species, 95% on one host genus and 99% on one host family (Skoracka et al. 2010).
Between 2009 and 2013, field investigations were conducted in southern part of China in order to look for eriophyoids on tea plants, leading to the discovery of a new genus and two new species. It is worth noting that the new genus and the new species were also found on the type host Rapanea neriifolia (Sieb. et Zucc.) Mez (Myrsinaceae).
Along with the current new records, thirteen species have been reported from tea plants worldwide (Table 1). They infest leaves in most cases, occasionally buds, stems and flowers. Some species can cause great economic loss to tea plants. This is the case of Acaphylla theae (Watt), a major pest all over the world, inducing leaf russeting, and Calacarus carinatus (Green), which causes bronzing and white cast skin streaks on both leaf surfaces. This paper describes the new genus and species, summarizes the main information on the eriophyoid mites found until now on tea plants, and provides a key to these mite species.

Material and methods
Plants were examined in field by the aid of hand-lens (30×) and eriophyoids, together with parts of their host plants, were placed in vials and stored in 75% ethanol. Each vial was marked with the collection data and herbaria were prepared for future identification of plant samples.
In the laboratory, the liquid contents were poured into a Petri dish from the vials, mite specimens were picked up using a fine pin and slide-mounted using Keifer's Booster and modified Berlese medium (Amrine and Manson 1996). Specimens were examined under a Zeiss A2 (Germany) research microscope equipped with phase contrast (A-plan phase objectives: ×10/0.25, ×20/0.45; EC plan-NEOFLUAR phase objectives: ×40/0.75; ×100/1.3 oil immersion) and drawings were made by camera Lucida. Images were taken with the same microscope (under 100× oil immersion with 10× eyepieces) using an Axio Cam MRc (Carl Zeiss) system, connected to a computer and using Axiovision image analysis software. The morphological terminology follows Lindquist (1996b) and Amrine et al. (2003), and the generic classification was made according to Amrine et al. (2003). The genera elevated after 2003 were arranged in the list by us. Specimens were measured according to de Lillo et al. (2010). For each species, the holotype female measurements precede the corresponding range for paratypes (given in parentheses). All measurements are in micrometers (μm) and are lengths when not otherwise specified. All type specimens are deposited as slide mounted specimens in the Arthropod/Mite Collection of the Department of Entomology, Nanjing Agricultural University (NJAU), Jiangsu Province, China.
Host plant names and their synonymies are in accordance with The Plant List (http://www.theplantlist.org/). Data on eriophyoid mites were extracted from the catalogue by Davis et al. (1982), Amrine and Stasny (1994) and from the computerized catalog of the Eriophyoidea (Amrine and de Lillo, pers. comm.); a further record was added based on the searching made on the most common abstract indexes. When available, the following information was summarized for each listed eriophyoid species based on literature: a) previous genus name assignment and possible synonymies; b) information about the host plant species; c) documenting relationships between eriophyoid species and host plants based on literature; d) distribution within geographic realms according to Udvardy (1975); e) the most relevant remarks.

Results
Thirteen eriophyoid mite species in eleven genera of two eriophyoid families have been reported from tea plants around the world (Table 1) and a key to eriophyoid mites on tea plants is provided below.
Etymology. The specific designation rapaneae is the genitive case derived from the genus name of the type host plant, Rapanea.
Etymology. The specific designation theacea is derived from the family name of the host plant; feminine in gender.
Differential diagnosis. This new species is similar to Paracaphyllisa adinandrae Kuang & Luo, 2005, but can be differentiated from the latter by the design of prodorsal shield which is provided with admedian and submedian lines (prodorsal shield design of P. adinandrae has median, admedian and submedian lines), smooth coxal plates (coxal plates have short lines in P. adinandrae) and coverflap with 23 (18-23) longitudinal ridges and dense short lines at its base (coverflap is smooth in P. adinandrae).
Remarks. The new species is surrounded with white hairs around the body.  Keifer, 1978 12 Prodorsal shield with median line complete, submedian lines curving from the median and forming a double loop between the dorsal tubercles, prodorsal shield laterally with a broad lobe over the coxae. Leg II with femoral seta (bv) absent, tarsal empodium 8-rayed ........Acaphyllisa indiae Keifer, 1954 -Prodorsal shield without median line, submedian lines not as above, prodorsal shield laterally without a broad lobe over the coxae. Leg II with femoral seta (bv) present, tarsal empodium 5-rayed ....Paracaphyllisa theacea sp. n.