#ZooKeys ZooKeys 1172: 31-46 (2023) DOI: 10.3897/zookeys.1172.106518 Research Article Two new species of Aphis (Toxoptera) Koch (Hemiptera, Aphididae) from China Zhentao Cheng", Xiaolei Huang'® 1 State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China Corresponding author: Xiaolei Huang (huangx/@fafu.edu.cn) OPEN Qaccess Academic editor: Colin Favret Received: 17 May 2023 Accepted: 6 July 2023 Published: 24 July 2023 ZooBank: https://zoobank. org/4B91D5EB-40A5-4F97-B080- 114D3463C38C Citation: Cheng Z, Huang X (2023) Two new species of Aphis (Toxoptera) Koch (Hemiptera, Aphididae) from China. ZooKeys 1172: 31-46. https://doi.org/10.3897/ zookeys.1172.106518 Copyright: © Zhentao Cheng & Xiaolei Huang. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International - CC BY 4.0). Abstract Two new aphid species, Aphis (Toxoptera) fafuensis Cheng & Huang, sp. nov., feeding on Adinandra millettii (Pentaphylacaceae) from Fujian, China, and Aphis (Toxoptera) sennae Cheng & Huang, sp. nov., feeding on Senna bicapsularis (Fabaceae) from Yunnan, China, were described. Morphological characters and molecular data supported the taxonomic position of the new species within the subgenus Aphis (Toxoptera). A key for identifying species of apterous viviparous females in this subgenus is provided. Key words: Aphids, CO/, DNA barcode, identification key, morphology, taxonomy Introduction The aphid genus Toxoptera was first proposed by Koch (1856), with 7. aurantiae Koch, 1856 designated as the type species. However, the name was considered as a synonym and the type species was revised as T. aurantii Boyer de Fonscolombe, 1841 by Schouteden (1906). Baker (1920) defined Toxoptera as having alate with once-branched media of the forewing. Williams (1921) described another unique character of this genus, which is a stridulatory apparatus consisting of peg-like spines on the hind tibiae and ventro-lateral spinulose ridges on the posterior abdominal segments. After Borner (1930) erected the genus Schizaphis to include species characterized by the once-branched media of the forewing, Toxoptera had been distinguished from allied genera by the presence of the stridulatory apparatus. Kim and Lee (2008) investigated the phylogenetic relationships within the tribe Aphidini using several gene markers including tRNA/COII, 12S/16S and EFT-a, and their results showed that Toxoptera may be non-monophyletic. Based on CO! sequences, Wang and Qiao (2009) showed that T. odinae was phylogenetically distinct from other Toxoptera species and should be reverted to Aphis (Aphis) odinae van der Goot, 1917 (Blackman et al. 2011). Then a molecular phylogenet- ic study of Aphis species based on nuclear and mitochondrial genes confirmed that Toxoptera should be regarded as a subgenus of Aphis (Lagos et al. 2014). Thus far, the subgenus Aphis (Toxoptera) has been represented by five spe- cies (Remaudiére and Remaudiére 1997; Favret 2023): A. (T.) aurantii Boyer de Fonscolombe, 1841, A. (T7.) celtis Shinji, 1922, A. (T.) citricidus Kirkaldy, 1907, 31 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China A. (T.) victoriae Martin, 1991 and A. (T.) chaetosiphon Qiao, Wang & Zhang, 2008. However, it should be noted that A. (T.) celtis is considered a possible synonym of A. (T.) aurantii (Martin 1991; Blackman and Eastop 2023). The host plants for species of this subgenus are very diverse, including Theaceae, Rutaceae, Rubiaceae, and many other plant families. New host plants can provide novel ecological niches for herbivorous insects, contributing to different host prefer- ences and genetic isolation. Therefore, host plant is key to the diversification of herbivorous insects and plays an important role in their speciation (Mitter et al. 1991; Futuyma and Agrawal 2009). Based on multiple gene fragments and the haplotype network analysis, Li et al. (2021) found that the population of A. (T.) aurantii feeding on Ficus showed great genetic difference from those feeding on other host plant groups, indicating that A. (T.) aurantii has been un- dergoing the evolution of host specialization on Ficus. In recent years, while collecting aphid samples in southern China, we ob- tained some samples that may represent two undescribed species from Adinandra millettii (Hook. & Arn.) Benth. & Hook. f. ex Hance (Pentaphylacace- ae) and Senna bicapsularis (L.) Roxb. (Fabaceae), respectively. By integrating morphological and molecular data, this paper describes the new species and confirms their taxonomic positions within Aphis (Toxoptera). Material and methods Field sampling The specimens of A. (T.) fafuensis Cheng & Huang, sp. nov. were collected in Fujian, China on Adinandra millettii and the samples of A. (T.) sennae Cheng & Huang, sp. nov. were collected in Yunnan, China on Senna bicapsularis. The de- tailed collection information is provided in Suppl. material 1: table S1. All sam- ples were preserved in 95% ethanol and kept at -80 °C for further morphological measurement and molecular experiments. Morphological description Six apterous viviparous females of A. (T.) fafuensis Cheng & Huang, sp. nov. and eight apterous viviparous females of A. (T.) sennae Cheng & Huang, sp. nov. were slide-mounted in Canada Balsam. Aphid terminology and the morpholog- ical measurements used in this paper followed Qiao et al. (2008) (Table 1). All specimens were examined and measurements and images were taken by using Nikon SMZ18 stereomicroscope. The measurements and the micrographs of mounted specimens were performed using a computer-connected Nikon set: Nikon Eclipse Ci-L upright microscope, 16MP digital camera with 0.55X adapter and imaging software NIS-Elements D ver. 4.60.00. The unit of measurement in this paper is millimeters (mm). The following abbreviations have been used: BL, body length; BW, body width; URS, ultimate rostral segment; URS_BW, basal width of URS; WR, whole length of rostral; WA, whole length of antenna; Ant. |, Ant. II, Ant. Ill, Ant. IV, Ant. V, Ant. Vib, for antennal segments I, Il, Ill, IV, V and the base of Ant. IV, re- spectively; Ant. III_WD, the widest diameter of Ant. III; PT, processus terminalis; PT_WD, the widest diameter of PT; HF, hind femur; HF_WD, the widest diameter ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 32 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China Table 1. Biometric data (mean, range) of Aphis (Toxoptera) fafuensis Cheng & Huang, sp. nov. and Aphis (Toxoptera) sennae Cheng & Huang, sp. nov. (in mm). A. (T.) fafuensis Cheng & Huang, sp. nov. Parts Apterous vivipara (N = 6) A. (T.) sennae Cheng & Huang, sp. nov. Apterous vivipara (N = 8) mean Length Ant. | 0.06-0.07 ec HF_WD 0.05-0.06 006 Cr =), No. of hairs on | URS Ant. | Ant. Il Ant. Ill Ant. IV Ant. V Ant. Vib U a 2 SE = Na NN} wo) =| Ol|n TE.) Sb Cauda QO > Gonapophyses Ratio (times) | BL/BW WA/BL HT/BL HF/BL SIPH/BL PT/WA Ant. III/WA ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 uo NY oO; wl on 1} o) | | | I I OV Bion; o;) Bh) Oo —_ iS as o O12 |2 NY wo) — 2.) S| | ; NN} wo) =) w a range 1.50-1.89 1.02-1.40 0.11-0.13 1.34-1.38 0.07-0.08 0.06-0.07 0.31-0.36 0.03 0.20-0.23 OAR O.22 0.09-0.10 0.34-0.37 0.44-0.53 0.07-0.09 0.83-1.00 0.05 0.09-0.11 0.17-0.20 0.07-0.10 0.04 0.17-0.20 OVT=OAS 0.01 0.02 0.02-0.03 23-35 82-95 912 20-529 8-13 12-16 4 Us Sa Bo) 0.8-0.9 0.5-0.6 0.3 0.1 0.3 0.2-0.3 33 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China A. (T.) fafuensis Cheng & Huang, sp. nov. A. (T.) sennae Cheng & Huang, sp. nov. Parts Apterous vivipara (N = 6) Apterous vivipara (N = 8) mean range mean range Ratio (times) PT/Ant. Vib 4.2 3.8-4.6 3.8 3.4-4.1 URS/URS_BW 2.5 22-28 2.6 2:0-3.3 URS/2HT 1.6 1.4-1.8 ARS 1.2-1.4 SIPH/Cauda 1.0 0.9-1.2 1.0 0.9-1.1 Cauda_BW/Cauda 0.5 0.4-0.7 0.7 0.6-0.8 HF/Ant. Ill 1.5 13-16 1.4 1.4-1.5 2HT/Ant. Ill 0.3 0.3 6.1 S767 URS/Ant. III 0.4 0.4-0.5 0.4 0.3-0.4 Ant. IIIH/Ant. IIlI.WD 0.5 0.5 0.3 0.3 HT_H/Ant. III_WD 1.2 0 1.5 0.8 0.8-1.0 SIPH/Ant. III_WD rx. 6.0-8.5 0.3 0.3 Ant. IIIWD/SIPH_BW 0.3 0.3-0.4 0.4 0.3-0.4 of HF; HT, hind tibia; HT_WD, the widest diameter of HT; 2HT, second hind tarsal segment; SIPH, siphunculus; SIPH_BW, basal width of siphunculus; SIPH_DW, distal width of siphunculus; Cauda_BW, basal width of cauda; AP anal plate; GP, genital plate; gona, gonapophyses. To examine the possible morphological differences between the two newly discovered species and A. (T.) aurantii, a one-way analysis of variance (ANOVA) was conducted. Furthermore, to identify pairwise differences of the morpholog- ical characters of specimens, post hoc multiple comparisons were performed using the Least Significant Difference (LSD) test (Suppl. material 1: table S2). All statistical analyses were carried out using SPSS ver. 24 (IBM, Chicago, IL, USA). Molecular analysis The whole genomic DNA of each sample was extracted from the single individual preserved in 95% ethanol using the DNeasy Blood & Tissue Kit (Qiagen, Hilden, Germany). The standard DNA barcode gene of aphids, cytochrome c oxidase subunit | (COI) was amplified with primer LepF (5-ATTCAACCAATCATAAAGA- TATTGG-3’) and LepR (5-TAAACTTCTGGATGTCCAAAAAATCA-3’) (Foottit et al. 2008). PCR amplifications were performed in a final volume of 25 uL reaction mixture containing 2 uL of template DNA, 0.5 uL of both forward and reverse prim- er (10 uM), 0.25 uL of Taq DNA polymerase (5 U/uL), 17.25 uL of double distilled H,0, 2.5 uL of 10x buffer and 2 pL of dNTP. PCR thermal regime was as follows: 5 min of initial denaturation at 95 °C, 35 cycles of 20 s at 94 °C, 30s at 50 °C (the annealing temperature) and 2 min at 72 °C, and 10 min of final extension at 72 °C. The products of PCR were visualized by electrophoresis on a 1% agarose gel and then bidirectionally sequenced at Beijing Tsingke Biotech Co., Ltd. (Beijing, China). The maximum-likelihood phylogenetic tree base on CO/ sequences includes thirty-six samples representing the two new species and three Aphis (Toxoptera) species including A. (T.) aurantii, A. (T.) citricidus and A. (T.) chaetosiphon were re- constructed. A. (T.) celtis and A. (T.) victoriae were excluded from the phylogenetic analysis, as A. (T.) celtis did not have any available CO/ sequence and the sequenc- es of A. (T.) victoriae in GenBank did not provide enough sites for analysis after alignment with other sequences. Aphis (Aphis) gossypii Glover, 1877 and Aphis (Aphis) odinae were used as outgroups (Fig. 3, Table 2). All sequences were as- ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 34 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China sembled by ContigExpress (Vector NTI Suite 6.0, InforMax Inc.), and the reliability was checked by BLAST. Multiple alignment was conducted using MAFFT (Katoh and Standley 2013) based on the default setting. Maximum-likelihood phylogenies were inferred using PhyloSuite ver. 1.2.3 (Zhang et al. 2020) under the TIM2+I+F model for 5000 ultrafast bootstraps. The mean genetic distances among the sev- en Aphis species used for phylogenetic analysis were calculated using MEGA 7 (Kumar et al. 2016) under Kimura’s two-parameter (K2P) model (Kimura 1980). Table 2. Voucher information and GenBank accession numbers of aphid samples used in molecular data analysis. Species A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) aurantii A. (T.) sennae Cheng & Huang, sp. nov. A. (T.) fafuensis Cheng & Huang, sp. nov. A. (T.) fafuensis Cheng & Huang, sp. nov. A. (T.) fafuensis Cheng & Huang, sp. nov. A. (T.) chaetosiphon A. (T.) chaetosiphon A. (T.) chaetosiphon A. (T.) chaetosiphon A. (T.) citricidus A. (T.) citricidus A. (T.) citricidus A. (T.) citricidus A. (T.) citricidus A. (T.) citricidus A. (T.) citricidus A. (A.) odinae A. (A.) gossypii Voucher number HL_20150518_4 HL_20150530_3 HL_20150705_2 HL_20150705_3 HL_20150907_1 HL_20150907_2 HL_20160119_1 HL_20160212_1 HL_20160409_6 HL_20160412_13 HL_20160607_2 HL_20161118_1 HL_20170429_29 HL_20170429_35 HL_20170521_3 HL_20170609_19 HL_20170614_13 HL_20170811_8 HL_20170922_13 HL_zld20171111_7 HL_20160627_3 HL_20150517_5 HL_20180423_6 HL_20180119_1 HL_20180423_5 HL_20150418_7 HL_20151226_7 HL_20150802_8 HL_20150821_1 HL_20150907_10 HL_20170205_4 HL_20180128_4 HL_20180616_8 HL_zld20171101_14 HL_20161017_4 HL_20150822_8 ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 Host plant Ilex latifolia Michelia alba Camellia sinensis Camellia sinensis Loropetalum chinense Ilex cornuta Citrus maxima Pittosporum tobira Ficus elastica Schefflera actinophylla Adinandra millettii Camellia sinensis Gleditsia sinensis Camellia cuspidata Camellia sp. Schima superba Murraya exotica Citrus reticulata Camellia sinensis Senna bicapsularis Adinandra millettii Adinandra millettii Adinandra millettii Camellia sp. Camellia oleifera Camellia japonica Camellia oleifera Pyracantha fortuneana Citrus reticulata Citrus reticulata Unknown Zanthoxylum piperitum Maclura tricuspidata Citrus reticulata Rhus chinensis Salvia splendens Location Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Changsha, Hunan Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Hangzhou, Zhejiang Hangzhou, Zhejiang Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Xishuangbanna, Yunnan Fuzhou, Fujian Kunming, Yunnan Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Fuzhou, Fujian Xian, Shanxi Emeishan, Sichuan Fuzhou, Fujian Shenzhen, Guangdong Haikou, Hainan Hangzhou, Zhejiang Chongzuo, Guangxi Fuzhou, Fujian Leshan, Sichuan Accession Number MH821442 OK285285 0Q985354 0Q985355 MH821475 MH821486 MH821519 0Q985356 0Q985357 MH821564 MH821575 MH821619 0Q985358 MH821131 MH821175 MH821220 MH821231 MH821297 MH821386 0Q985359 0Q985360 0Q985361 0Q985362 ON754448 ON754765 MH821874 MH821863 MH821930 MH821941 MH821952 MH821886 ON754472 ON754827 MH821963 MH821355 MH821146 35 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China Specimen deposition The holotypes and paratypes of the new species and all the other specimens examined here are deposited in the Insect Systematics and Diversity Lab, Fuji- an Agriculture and Forestry University, Fuzhou, China. Taxonomy Aphis (Toxoptera) fafuensis Cheng & Huang, sp. nov. https://zoobank.org/13AFFC64-CF53-4E58-8953-6FA9067D43A5 Figs 1, 4A-C Description. Apterous viviparous females: Body elliptical (Fig. 4A), dark brown in life, head is slightly lighter in color and the tibiae are markedly pale (Fig. 4B). Mounted specimens: Head. Vertex convex, antennal tubercles slightly de- veloped. Head with one pair of cephalic hairs, one pair of antennal tubercular hairs. Dorsum of head smooth with 4-7 hairs. Dorsal hairs of head fine, and with developed small tubercles at bases. Antennae six-segmented, segments | and II dark brown, segments III-VIb and PT dark at distal end and with spinu- lose imbrications; 0.8-1.0 times as long as body. Length in proportion of seg- ments I-VI: 21-33, 21-28, 100, 61-76, 65-72, 26-33 + 107-138. Processus terminalis 3.8-4.6 times as long as basal part of the segment. Antennal hairs acute, segments I-VI each with 5-6, 3-4, 4-8, 3-5, 2-4, 3 + 5-6 hairs, respec- tively, apical part of processus terminalis with 0-4 hairs. Length of hairs on segment II| 0.01 mm, 0.5 times as long as the widest diameter of segment III. Rostrum long, apical part dark brown, reaching hind coxae or abdominal seg- ment I. Ultimate rostral segment wedge-shaped, 2.2—2.8 times as long as basal width, 1.4-1.8 times as long as second hind tarsal segment. Ultimate rostral segment with four pairs of hairs, including one pair of accessory hairs. Thorax. Dorsal and ventral cuticle with polygon reticulations. Mesosternal furca with separated arms. Length of single arms 0.09-0.11 mm, 0.4-0.5 times as long as antennal segment Ill. Spiracles elliptical, spiracular plates dark brown. Prothorax with one pair of small marginal tubercles. Dorsal setae on thorax short and pointed, with small tuberculate bases. Legs normal. Distal part of femora, basal and distal part of tibiae dark brown, others brown. Hind femur 1.3-1.6 times as long as antennal segment Ill, hind tibia 0.5—0.6 times as long as body. Hind tibia with 7-8 peg-shaped spines, on basal two-thirds of inner side. Length of hairs on hind tibia 0.02-—0.03 mm, 1.0-1.5 times as long as the widest diameter of antennal segment Ill. First tarsal chaetotaxy: 3, 3, 2. Second tarsal segments with transverse imbrications. Abdomen. Abdominal segments IV-VI with ventro-lateral spinulose ridges, forming a stridulatory surface. Marginal tubercles on abdominal segments | and VII. Abdominal dorsal hair sparse, fine, with tuberculate bases. Abdominal tergite VIII with two hairs. Siphunculi dark brown, cylindrical, with broad base, tapering towards the apex, with spinulose transverse imbrications, without flange or hairs. Siphunculi 0.12-0.17 mm, 1.9-2.8 times as long as its basal di- ameter, 0.9-1.2 times as long as cauda. Cauda short tongue-shaped, constrict- ed in middle, 1.4-2.3 times as long as its basal diameter, with 14-21 hairs. Anal plate broad and round, with 18-21 hairs. Genital plate transversely oval, ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 36 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China Figure 1. Aphis (Toxoptera) fafuensis Cheng & Huang, sp. nov., apterous viviparous female A dorsal view of body B dorsal view of head C antennal segments I-III D antennal segments V-VI E mesosternal furca F ultimate rostral segment G siphunculus H genital plate | cauda J ventro-lateral stridulatory ridge of abdominal segments IV-VI K stridulatory ridge L anal plate M peg-shaped hairs on hind tibia N marginal tubercle on prothorax O marginal tubercle on abdominal segment | P marginal tubercle on abdominal segment VII Q gonapophyses. Scale bars: 0.10 mm. (A, N from HL_20160627_3_A; E, F, |, O from HL_20150517_5_A; C, G, J, K, M, P Q from HL_20150517_5_B; B, D, H, L from HL_20150517_5_C.). ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 37 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China with 11-18 hairs. Cauda, anal plate and genital plate dark brown with dense spinules. Gonapophyses three, each with 3-5 hairs. Specimens examined. Holotype: apterous viviparous female, CHINA: Fujian (Fu- zhou, 26.1°N, 119.3°E, Alt. 258 m), 27 June 2016, No. HL_20160627_3_A, on Adinan- dra millettii, coll. X. L. Huang and X. L. Lin (FAFU). Paratypes: 4 apterous viviparous females (No. HL_20150517_5_A, No. HL_20150517_5_B, No. HL_20150517_5_C and No. HL_20150517_5_D), CHINA: Fujian (Fuzhou, 26.1°N, 119.3°E, Alt. 258 m), 17 May 2015, on Adinandra millettii, coll. X. L. Huang and X. L. Lin (FAFU). Etymology. The new species is named after FAFU, the abbreviation for Fujian Agriculture and Forestry University, where the samples of this species were first discovered and collected. And ‘fafuensis’ is an adjective of feminine gender in accord with the feminine Aphis. Host plant. Adinandra millettii (Hook. & Arn.) Benth. & Hook.f. ex Hance (Pentaphylacaceae). Distribution. China: Fujian Province (Fuzhou, Quanzhou and Wuyishan). Biology. This species feeds on shoots and undersides of young leaves of the host plant, and can be attended by at least two species of Crematogaster (Fig. 4B, C) according to our records. Taxonomic notes. Aphis (T.) fafuensis Cheng & Huang, sp. nov. has black- and-white banded antennae. Siphunculi and cauda are dark. Most part of femora, basal and distal parts of tibiae are dark brown. The peg-like spines on the hind tibiae and roughened ventro-lateral cuticle on the posterior part of the abdomen form a typical stridulatory apparatus. Compared with A. aurantii, the new species has a smaller body size and stubbier siphunculi: body length 0.91-1.19 mm (A. aurantii: 1.14-1.71 mm), siphunculi length 1.9-2.8 times of siphunculi basal width (A. aurantii: 2.0-3.8 times). The results of ANOVA anal- ysis showed that there were significant differences between A. (T.) fafuensis Cheng & Huang, sp. nov. and A. (T.) sennae Cheng & Huang, sp. nov. and A. (T.) aurantii in some characters, such as the length of URS_BW, and the ratios of Ant. | and Ant. II to WA (Suppl. material 1: table S2). Aphis (Toxoptera) sennae Cheng & Huang, sp. nov. https://zoobank.org/3C5B676B-AEDE-4757-9136-AD087DBOE2D3 Figs 2, 4D Description. Apterous viviparous females: Body pear-shaped, reddish brown in life, with black-and-white banded antennae and dark head, femurs, siphunculi and cauda (Fig. 4D). Mounted specimens: Head. Dorsum of head smooth. Antennal tubercles slightly developed. Median frontal tubercle developed, slightly below antennal tubercles. Dorsal hairs 6-7, fine, with small developed tuberculate bases. Head with one pair of cephalic hairs, one pair of antennal tubercular hairs. Antennae six-segmented, segments | and II] smooth, dark brown, segments III-VIb and PT imbricated, dark at distal end. Whole antennae 0.8-0.9 times as long as body. Length in proportion of segments I-VI: 19-25, 19-22, 100, 59-69, 61-69, 25- 31 + 94-116. Processus terminalis 3.4—4.1 times as long as basal part of the segment. Antennal segments I-VI each with 4, 4, 5-9, 3-5, 3-4, 2-3 + 4-6 hairs, respectively, apex of processus terminalis usually with 3-4 hairs. Length ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 38 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China of hairs on segment III 0.01 mm, 0.3 times as long as the widest diameter of segment Ill. Rostrum reaching hind coxae. Ultimate rostral segment wedge- shaped, 2.0-3.3 times as long as basal width, 1.2—1.4 times as long as second hind tarsal segment. Ultimate rostral segment with three pairs of hairs, including one pair of accessory hairs. Thorax. Mesosternal furca with separated arms. Length of single arms 0.10- 0.14 mm, 0.3-0.4 times as long as antennal segment III. Prothorax with one pair of small marginal tubercles. Dorsal hairs on thorax short and thin, with small tuberculate bases. Legs normal. Distal part of femora, basal and distal part of tibiae dark brown, others brown. Hind femur 1.4—1.5 times as long as antennal segment Ill. Hind tibia 0.5-0.6 times as long as body, with 8-10 peg-shaped spines, on basal two-thirds of inner side. Length of hairs on hind tibia 0.02-0.03 mm, 0.8-1.0 times as long as the widest diameter of antennal segment III. First tarsal chaetotaxy: 3, 3, 2. Second tarsal segments with transverse imbrications. Abdomen. Abdominal segments IV-VI with ventro-lateral spinulose ridges, forming a stridulatory surface. Abdominal segments | and VII each with one pair of marginal tubercles. Abdominal dorsal hair sparse, fine, with tuberculate bases. Abdominal tergite VIII with two hairs. Siphunculi dark brown, cylindri- cal, tapering towards the apex, with spinulose transverse imbrications, without flange or hairs. Siphunculi 0.17-0.20 mm, 1.9-2.7 times as long as its basal diameter, 0.9-1.1 times as long as cauda. Cauda short tongue-shaped, con- stricted in middle, 1.2-1.8 times as long as its basal diameter, with 9-17 hairs. Anal plate broad, with 20-29 hairs. Genital plate transversely oval, with 8-13 hairs. Cauda, anal plate and genital plate dark brown with dense spinules. Go- napophyses three, each with 4-5 hairs. Specimens examined. Holotype: apterous viviparous female, CHINA: Yunnan (Kunming, 25.1°N, 102.7°E, Alt. 1900 m), 11 Nov. 2017, No. HL_zld20171111_7_A, on Senna bicapsularis coll. L. D. Zeng (FAFU). Paratypes: 7 apterous vivipa- rous females (No. HL_zld20171111_7_B, No. HL_zld20171111_7_C, No. HL_ 71d20171111.7_D, No. HLzzld20171111_72E,. No; HLzld20171111_7_F, No: HL_zld20171111_7_G and No. HL_zld20171111_7_H), with the same collection date as holotype (FAFU). Etymology. The new species is named after the genus name of the host plant, Senna bicapsularis. The word ‘sennae’ is a noun, and does not change spelling based on gender. Host plant. Senna bicapsularis (L.) Roxb. (Fabaceae). Distribution. China: Yunnan Province (Kunming). Biology. It seems the species feeds on seed pods of the host plant. Taxonomic notes. Aphis (T.) sennae Cheng & Huang, sp. nov. has black- and-white banded antennae, and processus terminalis are dark, different from A. aurantii whose processus terminalis are dark basally and distally. Siphunculli length 1.9-2.7 times of siphunculi basal width (A. aurantii: 2.0—3.8 times). The body length of A. (T.) sennae Cheng & Huang, sp. nov. is 1.50-1.89 mm, which is significantly larger than A. (T.) fafuensis Cheng & Huang, sp. nov. (0.91-1.19 mm). Body color of A. (T.) sennae Cheng & Huang, sp. nov. is reddish brown, the head is slightly darker, and immatures are almost the same color as adult apterae. Adult apterae of A. aurantii and A. (T.) fafuensis Cheng & Huang, sp. nov. are brownish-black, the nymphs of these two species are lighter in body color, or red- dish brown. The results of ANOVA analysis and the LSD test revealed significant ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 39 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China Figure 2. Aphis (Toxoptera) sennae Cheng & Huang, sp. nov., apterous viviparous female A dorsal view of body B dorsal view of head C antennal segments I-IIl D antennal segments V-VI E mesosternal furca F ultimate rostral segment G siphunculus H genital plate | cauda J ventro-lateral stridulatory ridge of abdominal segments IV-VI K stridulatory ridge L anal plate M peg-shaped hairs on hind tibia N marginal tubercle on prothorax O marginal tubercle on abdom- inal segment | P marginal tubercle on abdominal segment VII Q gonapophyses. Scale bars: 0.10 mm. (D, J, Q from HL_zld20171111_7_A; B, H, M from HL_zld20171111_7_B; L from HL_zld20171111_7_C; A, E, G, I, K, N, O, P from HL_ zld20171111_7_D; B from HL_zld20171111_7_G; F from HL_zld20171111_7_H.). ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 40 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China 84 56 HL 20170609. 19 HL 20170614 13 961 HL 20150705 2 HL_20150518 4 HL_20150530_ 3 HL_ 20160412 13 HL 20160119 1 HL 20150907 1 HL 20170429 29 HL_20170429 35 1 HL 20160409 6 | HL 20150705 3 Aphis (Toxoptera) autantii HL_20150907 2 HL_20160212 1 HL_20161118 1 HL 20170811 8 @ HL _20160627 3 z 100 @ HL_20150517_5 @ HL_20180423 6 A ZLD_ 20171111_7 HL_20180119 1 HL_20150418 7 2} HL 20151226 7 HL_20180423 5 98 9 88 31! HL 20170521 3 HL_ 20160607 2 HL_20170922 13 : Aphis (Toxoptera) fafuensis Cheng & Huang sp. nov. j 7 Aphis (Toxoptera) sennae Cheng & Huang sp. nov. Aphis (Toxoptera) chaetosiphon HL_20150802_8 ZLD_ 20171101 14 82] HL_ 20150821 1 HL_20170205 4 HL_20150907_10 HL_ 20180616 8 HL 20180128 4 HL 20150822 8 j HL 20161017 4 j Aphis (Toxoptera) citricidus Aphis (Aphis) gossypii Aphis (Aphis) odinae 78 0.020 Figure 3. The maximum-likelihood phylogenetic tree of Aphis (Toxoptera) samples based on COI sequences. Numbers beside main nodes are bootstrap support values (>50). Solid circles and triangle mark the new species. ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 4] Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China Figure 4. A-C Aphis (Toxoptera) fafuensis Cheng & Huang, sp. nov., colony on the shoot and the underside of leaf of Adinandra millettii D Aphis (Toxoptera) sennae Cheng & Huang, sp. nov., colony on the seed pod of Senna bicapsularis. differences between A. (T.) sennae Cheng & Huang, sp. nov. and A. (T.) fafuensis Cheng & Huang, sp. nov., as well as between A. (T.) sennae Cheng & Huang, sp. nov. and A. (T.) aurantii, ina number of characters, including the measured length, ratio, and number of hairs on various body parts (Suppl. material 1: table S2). Molecular analyses The mean interspecific distance between A. (T.) fafuensis and A. (T.) aurantii was 2.8%, and the K2P distances between A. (T.) fafuensis and other species from Aphis (Toxoptera) ranged from 5.6% to 9.2%. Meanwhile, the mean interspecif- ic distance between A. (T7.) sennae and A. (T.) aurantii was 2.7%, and the K2P distances between A. (T.) sennae and other species within Aphis (Toxoptera) ZooKeys 1172: 31-46 (2023), DOI: 10.3897/zookeys.1172.106518 42 Zhentao Cheng & Xiaolei Huang: Two new species of Aphis (Toxoptera) from China ranged from 4.5% to 8.2%. The averages of pairwise sequence divergences of the CO! genes among thirty-six samples are presented in Table 3. The phylogenetic results showed that A. (T7.) fafuensis Cheng & Huang, sp. nov. and A. (T.) sennae Cheng & Huang, sp. nov. clustered together with the known species of Aphis (Toxoptera). Both the two new species showed mor- phologically and phylogenetically closer relationships with A. (7.) aurantii and A. (T.) fafuensis had a sister relation with A. (T.) aurantii, probably due to closer relationship of their host plants. Table 3. Mean genetic distances (K2P) among two new species and three known species of subgenus Aphis (Toxoptera) based on COI sequences. The percentage of genetic distances are shown in the lower left half of the matrix, and the percentage of standard errors are shown in the upper right half of the matrix. = = S 3 eo e326 5 < = 2a > eo So = & 8 3