﻿The Oriental fungus-feeding genus Azaleothrips Ananthakrishnan, 1964 from China with one new species and four new records (Thysanoptera, Phlaeothripidae, Phlaeothripinae)

﻿Abstract Azaleothrips, a genus of fungus-feeding Phlaeothripinae , is easily recognized by the complex sculpture on the body surface. It is species-rich in the Oriental region, with 10 species here recognized from China, including A.sphaericussp. nov. and four new records. An illustrated key to the species from China is provided.


Introduction
The fungus-feeding species in Phlaeothripinae belong to the Phlaeothrips-lineage and are usually found in dry, dead leaves, twigs, branches, and grasses (Mound and Marullo 1996).Of the 32 genera in this group recorded from China (Dang et al. 2014), Azaleothrips is easily recognized by the following combination of characters: body surface strongly reticulate, with many wrinkles or tubercles in lines (Figs 1-7); major setae short and broadly expanded at apex ; postocular setae close together and placed near inner margin of eyes; maxillary stylets retracted to eyes and medially close together.This genus was treated as a member of the Idiothrips group, with three genera, Idiothrips, Stegothrips, and Strepterothrips (Okajima 1976), of which the first two are unknown in China but easily distinguished from Azaleothrips, as indicated by Okajima and Masumoto (2014).Strepterothrips, of which only S. orientalis of the 15 known species is recorded from Taiwan, is closely related to the genus Azaleothrips (Okajima 1995;ThripsWiki 2023), but it can be distinguished by having one sense cone on antennal segment III and a well-developed fore tarsal ventral hamus (Okajima and Masumoto 2014).In addition, Strepterothrips species have seven antennal segments, with the morphological VIII joined to VII without a suture, are usually wingless, and have antennal segment II obviously ZooKeys 1183: 219-231 (2023), DOI: 10.3897/zookeys.1183.113182 Lihong Dang et al.: Azaleothrips from China larger than segment I. In comparison, Azaleothrips has antennal segment VIII distinct from VII and with at least a complete suture , is usually macropterous, and antennal segment II is regular.A related genus, Stictothrips, also shares the complex body sculpture and fan-shaped major setae with Azaleothrips, but it has the fore wings curiously constricted and twisted (Mound and Tree 2015).
In the process of identifying slides of Azaleothrips from China, two species were recognized, A. laevigatus and A. dentatus, which seem to be unusual in having the dorsal view of body not heavily reticulate (Fig. 2), the maxillary stylets and mouth cone elongate (Fig. 3), and the major setae relatively longer.These two are similar to females of the genus Ablemothrips, with which they share the following characters: postocular setae close, antennal segments VII-VIII fused, antennal segments III-IV with three and four sense cones respectively, and forewings slender and weakly medially constricted.The only character state that distinguishes Ablemothrips from the above two species is the sexual dimorphism in the position of the postocular setae, which are widely separated in males of all three Ablemothrips species (Okajima 1999).This condition is not recorded in any Azaleothrips.
Among the 35 species of Azaleothrips, two species groups have been recognized: the amabilis species group with nine species, and the moundi species group with 26 species (Okajima and Masumoto 2014).In China, only two species have been recorded (Han 1992;Dang et al. 2014), A. moundi and A. siamensis, but three more were described from Taiwan by Okajima and Masumoto (2014): A. formosae, A. taiwanus, and A. atayal.
The objective here is to recognize species of the Oriental genus Azaleothrips in the first author's thrips collection, to describe a new species, and to provide an illustrated key to 10 Chinese Azaleothrips species, including four new records for A. laevigatus, A. laocai, A. lepidus and A. templeri.The new species, A. sphaericus sp.nov., obviously belongs to the moundi species group because it has two sense cones on antennal segment III (Fig. 13), closely fused VII-VIII (Fig. 13), no fore-tarsal tooth in either sex, an expanded S2 on male tergite IX (Fig. 28), and many short discal setae on the pronotum and metanotum .

Materials and methods
The descriptions and photomicrographs were produced from slide-mounted specimens under a Nikon Eclipse 80i microscope with a Leica DM2500 camera and using differential interference contrast illumination.These images were processed with Automontage and Photoshop v. 7.0.The abbreviations used for the pronotal setae are as follows: am -anteromarginal, aa -anteroangular, ml -midlateral, epim -epimeral, pa -posteroangular.The unit of measurement in this study is the micrometre.Most specimens studied here are available in the School of Bioscience and Engineering, Shaanxi University of Technology (SNUT), Hanzhong, China, the Australian National Insect Collection (ANIC), Canberra, Australia, and the National Zoological Museum of China (NZMC), Institute of Zoology, Chinese Academy of Sciences, Beijing, China.Additionally, two slides of types were loaned from Taiwan Agricultural Research Institute (TARI), Taiwan, China.
Note.The number of sense cones on antennal segments III-IV is a very diagnostic character in many thysanopteran taxa.Especially in Azaleothrips, two species groups were proposed because of two sense cones on III and two or three cones on IV in the moundi species group, and three and four on antennal segments III-IV, respectively, in the amabilis species group.These numbers vary between species, but are stable within each species.Furthermore, the macropterous forms in this genus are very common, but three species also have micropterae which usually bear three well-developed sub-basal setae, A. moundi, A. simulans and A. sphaericus sp.nov., that all belong to moundi species group.The complex sculptures on the body surface are also various ranged from weakly reticulate to strongly reticulate with wrinkles or tubercles inside or along lines.Therefore, these variations are not helpful to give a clear generic diagnosis, but fortunately an excellent one is available in a recent paper (Okajima and Masumoto 2014).Comments.Described from Taiwan on dead leaves and branches, this species is a member of the amabilis species group, as indicated by Okajima and Masumoto (2014).Azaleothrips atayal is closely related to another Taiwan species, A. formosae, which can be distinguished from A. formosae by its darker body; it has also been collected at lower altitudes, as mentioned by Okajima and Masumoto (2014).Unfortunately, no specimen was studied here, but the species is readily placed in the above key using the excellent illustrated description.Comments.This species was described on many specimens, including types and non-types, from Taiwan that were collected on dead branches.A female and two males from Yunnan are identified as A. formosae because they show no difference in their morphology.However, they differ in their coloration; the female has the prothorax largely yellow, like non-paratypic specimens from Kenting National Park (Taiwan), and one male has a brownish prothorax (Fig. 15), slightly paler than the head, and all femora yellowish brown with the apical quarter pale; the other male has a pale prothorax, like the paratypes.Moreover, the pore plate on abdominal sternite VIII is a little broader in the Yunnan specimens (Fig. 27), but S2 setae on tergite IX are pointed at the apex, as in the types.Comments.Described from Japan on dead Casuarina branches, this species is distinguished easily from other Azaleothrips, except for two Philippine species, A. philippinensis and A. bifidius, in having S2 on abdominal tergite IX of males pointed at its apex (Fig. 29).Azaleothrips laevigatus can be distinguished from these Philippine species by the weaker sculpture on the head and pronotum and transverse pore plate on male sternite VIII (Figs 2,16,29).This species is closely related to an Indonesian species, A. dentatus, in having weak sculpture on the body surface and shorter major setae, and in the head shape, but in A. dentatus the fore-tibia has an apical inner tubercle.Additionally, the head of A. laevigatus has weak sculpture, almost straight cheeks, postocular setae close together and slender, and long stylets that reach the eyes (Fig. 2), similar to species of Ablemothrips.However, A. laevigatus has a long mouth-cone which is sharply pointed and reaching the mesopresternum (Fig. 3), and the postocular setae are also close together in male, while Ablemothrips species have the mouth coneshort and rounded, and the postocular setae of males are sexually dimorphic and widely separated (Okajima 1999).A female and male from Guangxi, China are recognized as A. laevigatus because there is no differences in morphology and coloration, as compared to the original description (Okajima 2006).Comments.Azaleothrips laocai was described from Vietnam on dead branches.It belongs to the amabilis species group, which bears three and four sense cones on antennal segments III and IV, respectively.Currently, this species has the largest body size of any known Azaleothrips species, with two females from Shaanxi, China about 2270-2350 μm in body length, whereas the body lengths of other Azaleothrips spcies are usually no more than 2000 μm.These two females from Shaanxi show a little difference in antennae coloration; segment IV is brown, with the apex and base pale, as well as the base of V pale (Fig. 9), but in the original description of A. laocai the basal neck of IV is yellowish and V is uniformly brown.Comments.This species, one of the two species from China that belong to the moundi species group, was described from Japan and Taiwan on dead twigs.It is unique in Azaleothrips because antennal segments III-IV both have two major sense cones (Fig. 11).The holotype female and paratype male of A. magnus Chen, 1980, which was synonymized with A. moundi by Okajima and Masumoto (2014), were here studied, but both specimens had crack inside the balsam that seems to have allowed entry of air under the cover slip.These specimens have the third antennal segment III clear yellow, as in the original description of A. moundi.Two micropterous female and male from Sichuan and Shanxi recognized here as A. moundi have antennal segment III shaded on apical half.This was also noted for A. Lepidus, as mentioned above.Okajima, 1978 Figs 6, 12, 18, 30 Azaleothrips siamensis Okajima, 1978:  Comments.Described from northern Thailand on dead leaves, this species was first recorded from China, Guizhou, by Han (1992).Here, six females and one male each from Guangxi, Chongqing, and Yunnan suggest that this species may be common in southern China.These specimens have much paler pronotum (Fig. 18) and shorter anal setae than the specimens described from Thailand in the original description (Okajima 1978), but no other differences have been observed.Description.Holotype.Female macroptera.Body uniform brown.Antennal segment III clear yellow (Fig. 13); other segments brown, but I-II slightly lighter than head.All femora brown, with apices and extreme bases yellowish; all tibiae brown at middle, with apices and bases yellowish; mid-and hind-tibiae sightly paler.Fore-wing shaded with brown, paler in basal quarter.

Azaleothrips sphaericus
Head (Fig. 4).Head distinctly longer than wide; dorsal surface strongly sculptured with reticles, with scattered small wrinkles among reticles, especially between postocular setae.Compound eyes comparatively small, about 0.3 times as long as head.Postocular setae shorter than half length of eyes.Antennal segments VII and VIII tightly fused (Fig. 13); median segments spherical, III smaller than IV; segment III with two (1 + 1), segment IV with three (1 + 2) sense cones.
Abdomen (Figs 24,28).Pelta distinctly medially reticulate, with delicate wrinkles within reticles (Fig. 20).Abdominal tergites II-VII weakly sculptured with transverse reticles or lines, dentate microtrichia in lateral third, with two pairs of wing-retaining setae; posterior pair much larger than anterior pair.Tergite VIII with a pair of small setae medially; tergite IX with four short setae at middle (Fig. 28); S1 setae on tergite IX a little shorter than half length of tube, expanded at apex (Fig. 28); S2 slightly longer than S1, expanded at apex (Fig. 28); S3 as long as tube, pointed at apex.Tube short, about 0.6 times as long as head.Anal setae longer than tube.
Female microptera.Color and structure similar to macropterous female, but tubercles on lines of reticles in most part of head, metanotum, pelta, and posterior median portion of tergites II-VII; metanotum and pelta broad (Fig. 21); eyes and two pairs of wing-retaining setae relatively small.
Male microptera.Color and structure very similar to micropterous female, but mid-and hind-tibiae yellow with slightly shaded medially.Pore plate on abdominal sternite VIII distinct, narrow (Fig. 24).S2 on abdominal tergite IX expanded at apex, slightly longer than S1.
Etymology.Latin, sphaericus, referring to the spherical antennal segment III.
Comments.This new species is unusual among Azaleothrips species in having antennal segment III almost spherical and smaller than IV, a condition somewhat similar with some Strepterothrips species.The new species is similar to A. phuketanus and A. simulans in having two and three sense cones on antennal segments III and IV, respectively, but it differs from A. phuketanus in having antennal segment III shorter than IV (Fig. 13), the anterior part of metanotum with 15 small setae before the major pair of setae, whole of pronotum covered with tubercles (Figs 19,20), and S1 setae of tergite IX shorter than one-half the length of the tube (Fig. 28); in A. phuketanus antennal segment III is much longer than IV, the anterior part of metanotum bears seven small setae before the major pair of setae, the pronotum only has tubercles posterior to median, and S1 setae of tergite IX is longer than half the length of tube.It is distinguished from A. simulans in having antennal segments I-II concolorous with the head, VI uniformly brown, antennal segment III shorter than IV (Fig. 13), the dorsal surface of head reticulate and without an asperate area (Fig. 4), the metanotum with wrinkles among reticles and the anterior part of metanotum with 15 small setae before the major pair of setae (Fig. 20), and a hat-shaped pelta; in A. simulans antennal segments I and II are paler than the brown head, the basal neck of VI is yellow, antennal segment III much longer than IV, the dorsal surface of the head is reticulate but medially is aspirate and not reticulate, the metanotum is strongly asperate and without lines of reticulation at centrally, the anterior part of metanotum has at most 10 small setae before the major pair of setae, and the pelta is trapezoid.It is also similar to A. moundi in having antennae brown and only with III yellow and with two sense cones, in sculpture of the head and pronotum, and setae on tergite IX, but these species can be distinguished as follows.Azaleothrips sphaericus has antennal segment IV with three major sense cones, antennal segment III spherical, with a short stem (Fig. 13) which is almost as long as wide, antennal segment IV uniformly brown, postocular setae about half length of the eyes (Fig. 4), apices and bases of all tibiae pale, light brown, and pelta with tubercles on lines of transverse reticulation in microptera (Fig. 21); in A. moundi antennal segment IV has two major sense cones, antennal segment III is not spherical and longer than wide, basal neck of IV is paler, postocular setae shorter than one-half length of the eyes, all tibiae brown to dark brown, apices and bases of mid-and hind-tibia pale, and pelta polygonally reticulate in microptera.

Azaleothrips taiwanus Okajima & Masumoto, 2014
Azaleothrips taiwanus Okajima & Masumoto, 2014: 342.Comments.Described from Taiwan on dead branches, this species was not satisfactorily distinguished from another Taiwan species, A. atayal, in the original description (Okajima and Masumoto 2014).The only difference between these two species is the presence or absence of many small tubercles in the reticulation of head and pronotum, as indicated in the above key.Comments.Described from West Malaysia on dead leaves, this species is similar to A. lepidus in having pale pronotum (Fig. 22) and fore-femora, but A. templeri can be easily distinguished from other Chinese species of Azaleothrips.It is distinguished by the presence of polygonal reticulation on the posterior half of the dorsal surface of metathorax (Fig. 23).A female from Guangxi is identified as A. templeri, and this is the first record of the species from China.A male from Laos is also recognized here as this species.