Phytoseiid mites have been intensively surveyed in Taiwan during the past decades because of their potential as biological control agent. Despite the fact, many regions of Taiwan remain under-explored especially in mountain areas and neighboring islands. Typhlodromus (Anthoseius) crossostephium sp. nov. was collected from Crossostephium chinense (L.) Makino (Asteraceae) on rocky shore habitat during a survey on Lanyu Island. In this paper, presence of a phytoseiid mite on rocky shores is reported for the first time. A detailed morphological description of the new species and a key to the Taiwanese species of subgenus Anthoseius are provided.
Introduction
Phytoseiid mites have received considerable attention because of their potential as biological control agents of phytophagous mites and other small arthropods (McMurtry et al. 2013). Thus far, more than 2,700 species included in 91 genera and three subfamilies, have been recorded worldwide (Chant & McMurtry 2007; Demite et al. 2017). Lanyu Island (also called Botel Tobago Island or Orchid Island) is located southeast of Taiwan and north of Luzon Island, Philippines. Since the 19th century, the great diversity of fauna found in this 48 km2 island has attracted several taxonomists. Tseng (1975) reported three phytoseiid species in Lanyu Island, including Shiehia multispinosa Tseng (= Neoseiulella compta (Corpuz)), Typhlodromus (Anthoseius) tridentiger Tseng, and T. (A.) lanyuensis Tseng. Liao et al. (2017) described Euseius paraovalis Liao & Ho. However, knowledge of Lanyu phytoseiid mites is fragmented.
Phytoseiid mites are free-living and terrestrial mites distributed worldwide, with diverse habitats, from the tundra region to tropical rain forests (Chant 2007; McMurtry et al. 2013). These mites extensively exploit the foliage habitat of higher plants, and can be discovered in any place covered with vegetation (Chant & McMurtry, 2007; McMurtry et al. 2013). However, the phytoseiid fauna of coastal regions remains poorly identified, particularly those on the rocky shores. Moraes & Oliveira (1982) and Stathakis et al. (2016) reported phytoseiid mites found in the coastal areas, but only in the vegetative lands, not the rocky shores. A rocky shore is a harsh habitat for mites. Mites found in rocky shores are typically oribatids and rarely mesostigmatids (e.g. families Digamasellidae, Rhodacaridae) (Barendse et al. 2002). This study presents one new species Typhlodromus (Anthoseius) crossostephium sp. nov. found on C. chinense on the rocky shores of Lanyu Island. Descriptions of both sexes are provided, along with a key to Taiwanese Typhlodromus (Anthoseius) species.
Materials and Methods
Specimens examined in this study were collected from Lanyu Islands during 2009–2016, with a particular focus on coastal region. Specimens were mounted in Hoyer's medium. Phytoseiid mites were examined under an optical microscope (Olympus® BX51), and measured using stage-calibrated ocular micrometers and ImageJ 1.47 computer program (Schneider et al. 2012), photos taken by microscopic camera (Motic® Moticam 5+). All measurements were provided in micrometers, holotype measurements are shown in bold type for the new species, followed by their mean and range in parentheses. The general terminology used for morphological descriptions in this study follows that of Chant & McMurtry (2007), while for idiosomal seta terminology followed Rowell et al. (1978) and Chant & Yoshida-Shaul (1991, 1992); for adenotaxy and poroidotaxy terminology we followed Beard (2001). Type specimens and voucher specimens were deposited in the following institutions: ESALQ-USP (Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, State of São Paulo, Brazil), NCHU (Department of Entomology, National Chung Hsing University, Taichung, Taiwan), NMNS (National Museum of Natural Science, Taichung, Taiwan), NTU (Department of Entomology, National Taiwan University, Taipei, Taiwan), NPUST (National Pingtung University of Science and Technology, Pintung County, Taiwan), TARI (Taiwan Agricultural Research Institute, Taichung City, Taiwan), TARL (Taiwan Acari Research Laboratory, Taichung City, Taiwan). Additionally, two paratypes (Aca25-3, 6) and two voucher specimens (Aca4301, 4335) of the closely related species T. philippinensis were received on loan from UPLB-MNH (Museum of Natural History, University of the Philippines Los Banos, Los Banos, Philippines), in order to confirm important morphological characters. If necessary, the locality names were translated using the Geographic Name Information System, Department of Land Administration, Ministry of the Interior (Taiwan) ( http://gn.moi.gov.tw/geonames/Translation/Translation.aspx).
Results
Description of new species
Typhlodromus (Anthoseius) crossostephium sp. nov. Liao & Ho
Diagnosis
Female dorsal surface mostly reticulated, bearing 21 pairs of dorsal setae (including r3, R1). All setae smooth, shovel-shaped apically except for Z4 and Z5 which are distinct shovel-shaped apically with expanded blade1. Five pairs of solenostomes, (gd2, gd4, gd6, gd8, gd9) visible on the dorsal shield. Peritreme extending to level of setae j1. Sternal shield with three pairs of setae; ventrianal shield bearing four pairs of pre-anal setae, with solenostomes (gv3). Fixed digit of chelicera with four teeth; movable digit with three teeth. Spermatheca with calyx bell-shaped. Leg III and leg IV both with three pair of shovel-shaped macrosetae; genu II with seven setae. Male ventrianal shield bearing six pairs of pre-anal setae; spermatodactyl foot L-shaped.
Female (n=10)
A lightly sclerotized mite. Idiosomal setal pattern: 12A:8A/JV:ZV.
Dorsum (Fig. 2–A). Dorsal shield nearly oval, constricted at level of R1, with lateral reticulation; 317 319 (308–328) long (j1–J5 level) and 187 193 (187–206) wide at level of j6, 183 190 (180–199) wide at level of S4; five pairs of solenostomes on dorsal shield, (gd2, gd4, gd6, gd8, gd9), 13 pairs of lyrifissures, (id1, id2, id1a, id4, id6, idm2, idl2, idm3, idl3, idx, idl4, idm5, idm6); length of setae: j1 20 21 (19–23), j3 22 22 (19–24), j4 14 14 (11–18), j5 13 14 (12–16), j6 17 17 (16–19), J2 24 23 (21–27), J5 9 8 (6–11), z2 16 14 (13–16), z3 17 19 (16–21), z4 21 21 (17–23), z5 15 16 (13–20), Z4 32 31 (26–37), Z5 44 45 (41–51), s4 21 21 (19–24), s6 24 25 (22–29), S2 23 27 (23–31), S4 19 23 (19–31), S5 16 14 (9–18), r3 15 16 (14–19), R1 13 13 (11–15). All setae smooth, shovel-shaped apically except for Z4 and Z5 which are distinct shovel-shaped apically with expanded blade (Fig. 2–E).
Peritreme (Figs. 2–A, B). Peritreme extend to level of j1; peritremal shield lightly sclerotized, with one pair of solenostomes (gd3), one pair of lyrifissures (id3).
Venter (Fig. 2–B). Sternal shield smooth, posterior margin irregular, much wider than long, 52 55 (46–63) long, 79 84 (75–89) wide, with three pairs of setae st1 25 25 (22–29), st2 21 20 (19–21), st3 25 20 (15–25), and two pairs of lyrifissures (pst1, pst2). Exopodal shield at coxae II–IV. Metasternal platelets tear-shaped, with one pair of metasternal setae, st4 17 19 (15–22), with one pair of lyrifissures (pst3). Genital shield smooth, with one pair of genital setae st5 23 17 (12–23), 69 70 (65–75) wide at level of genital setae. Distances between st1–st1 46 46 (43–49), st2–ST2 57 60 (56–64), st2–st3 67 69 (66–72), st1–st3 62 62 (59–64), st5–st5 62 619 (59–67). Ventrianal shield pentagonal, smooth, 99 103 (98–109) long, 85 90 (84–95) wide at level of ZV2, 66 67 (63–71) wide at level of anus; with four pairs of pre-anal setae, JV1 15 13 (11–16), JV2 14 12 (8–16), JV3 10 13 (10–15), ZV2 16 14 (9–17), solenostomes gv3 crescentic; Pa 10 10 (8–14), Pst 9 10 (8–12) on shield. Setae JV4 11 11 (9–13), JV5 30 31 (26–37), ZV1 17 16 (13–19), ZV3 8 9 (6–12) on interscutal membrane. All setae smooth, sharp pointed, JV5 shovel-shaped. Two metapodal plates 20 21 (18–27) long, 3 4 (3–5) wide, 10 8 (5–12) long, 2 2 (1–2) wide.
Spermatheca (Fig. 2–D). Calyx bell-shaped, 17 16 (14–19) long, 7 8 (7–10) wide, atrium connected to the calyx with a neck, minor and major ducts visible.
Chelicera (Fig. 2–C). Movable digit 25 26 (25–28) long, with three teeth; fixed digit 26 25 (23– 26) long, anterior half with three teeth, posterior half with one tooth, with pilus dentilis.
Legs (Figs. 3). Coxal formula 2-2-2-1. Chaetotaxy (femur to basitarsus): leg I, 2-3/1-2/2-2, 2-2/ 1-2/1-2, 2-2/1-2/1-2, 1-1/1-1; leg II, 2-3/1-2/1-1, 2-2/0-2/0-1, 1-1/1-2/1-1, 1-1/1-1; leg III, 1-2/1-1/ 0-1, 1-2/1-2/0-1, 1-1/1-2/1-1, 1-1/1-1; leg IV, 1-2/1-1/0-1, 1-2/0-2/1-1, 1-1/0-2/1-1, 1-1/1-1. Macrosetae: Sge III (ad2) 14 14 (14–16), Sti III (ad) 11 11 (10–13), St III (ad) 9 9 (7–10), Sge IV (ad2) 22 22 (21–23), Sti IV (ad) 13 13 (12–15), St IV (ad) 24 25 (22–27). Marcrosetae apically shovel-shaped.
Male (n=10)
A lightly sclerotized mite. Idiosomal setal pattern: 13A: 8B/JV-4: ZV-1, 3.
Dorsum (Fig. 4–A). Dorsal shield nearly oval, constricted at level of R1, with lateral reticulation; 252 (240–270) long (j1-J5 level) and 168 (160–178) wide at level of j6, 135 (131–140) wide at level of S4, five pairs of solenostomes on dorsal shield, (gd2, gd4, gd6, gd8, gd9), thirteen pairs of lyrifissures, (id1, id2, id1a, id4, id6, idm2, idl2, idm3, idl3, idx, idl4, idm5, idm6); length of setae: j1 14 (10–19), j3 18 (16–20), J4 13 (11–16), J5 12 (11–14), j6 14 (11–16), J2 18 (16–21), J5 8 (6–10), z2 12 (10–13), z3 15 (13–17), z4 16 (14–18), z5 13 (11–16), Z4 24 (22–26), Z5 31 (29–34), s4 17 (15–21), s6 20 (18–23), S2 21 (20–22), S4 18 (16–19), S5 13 (11–15), r3 13 (11–16), R1 10 (9–12). All setae smooth, shovel-shaped apically except for Z5 which are distinct shovel-shaped apically with expanded blade.
Peritreme (Figs. 4–A, B). Peritreme extending to level of j1; peritremal shield lightly sclerotized, with one pair of solenostomes (gd3), one pair of lyrifissures (id3).
Venter (Figs. 4–B). Sternogenital shield smooth, lateral slightly reticulated, posterior margin with slightly medium projection, longer than wide, 110 (105–123) long, 65 (60–73) wide at level of st5, with five pairs of setae, st1 16 (13–18), st2 11 (7–15), st3 14 (9–18), st4 13 (9–16), st5 12 (1015), three pairs of lyrifissures (pstl, pst2, pst3). Distances between st1–st1 38 (36–42), st2–st2 54 (50–57), st3–st3 56 (53–61), st4–st4 42 (39–46), st5–st5 37 (34–42), stl–st5 110 (106–118). Exopodal shield at coxae II–IV. Ventrianal shield subtriangular, with striation, 97 (93–101) long, 136 (129–144) wide at anterior corner, 60 (52–97) at level of anus, fused with peritremal shield cingulum; with four pairs of pre-anal setae, JV1 12 (9–14), JV2 11 (10–12), JV3 10 (7–12), ZV2 11 (9–13), solenostomes gv3 crescentic; Pa 8 (7–12), Pst 9 (7–12) on shield. Setae JV5 16 (13–18) on interscutul membrane. All setae smooth, sharp pointed, JV5 shovel-shaped.
Chelicera (Fig. 4–C). Movable digit 18 (16–21) long, with one tooth; fixed digit 20 (18–21) long, anterior half with two teeth, with pilus dentilis. Spermatodactyl L-shaped, shaft 18 (18–18) long, heel rounded, foot 11 (9–13) long, with expanded toe and lateral thorn-like projection.
Legs (Figs. 5). Coxal formula 2-2-2-1. Chaetotaxy (femur to basitarsus): leg I, 2-3/1-2/2-2, 2-2/ 1-2/1-2, 2-2/1-2/1-2, 1-1/1-1; leg II, 2-3/1-2/1-1, 2-2/0-2/0-1, 1-1/1-2/1-1, 1-1/1-1; leg III, 1-2/1-1/ 0-1, 1-2/1-2/0-1, 1-1/1-2/1-1, 1-1/1-1; leg IV, 1-2/1-1/0-1, 1-2/0-2/1-1, 1-1/0-2/1-1, 1-1/1-1. Macrosetae: Sge III (ad2) 9 (7–12), Sti III (ad) 8 (7–10), St III (ad) 7 (7–8), Sge IV (ad2) 14 (13–16), Sti IV (ad) 9 (7–12), St IV (ad) 19 (16–21).
Type specimens
Holotype female: Lanyu Island, Elephant trunk rock (22°01.077′ N, 121°35.990′ E, 24 m), no. 1901– 3 from Crossostephium chinense (Compositae), 23.ix.2016, H. Y. Lin (NTU). Paratypes: Lanyu Island, Elephant trunk rock (22°01.077′ N, 121°35.990′ E, 24 m), six females (no. 467–1, 2, 3, 4, 5, 8) from C. chinense, 5.iv.2010, J. R. Liao & C. C. Ho (NMNS); Lanyu Island, Elephant trunk rock (22°01.077′ N, 121°35.990′ E, 24 m), 65 females 12 males (HAL099B481, 483, 484, 486, 488, 489, 490, 491, 492, 493, 495, 497, 498, 501, 502, 503, 505, 506, 507, 508, 509, 511, 512, 513, 514, 515, 516, 517, 519, 520, 522, 523, 524, 525, 526, 527, 528, 530, 531, 533, 534, 535, 536, 537, 539, 540, 541, 543, 544, 546, 547, 548, 549, 551, 553, 554, 555, 556, 557, 558, 559, 560, 561, 563, 565, 569, 571, 573, 574, 575, 577, 578, 579, 581) from C. chinense, 5.iv.2010, C. C. Ho (5 females in NTU, 4 females 4 males in NSNM, remaining in TARL); Lanyu Island, Elephant trunk rock (22°01.077′ N, 121°35.990′ E, 24 m), one female (no. 1647-2) from C. chinense, 4.ix.2016, H.Y. Lin (NPUST); Lanyu Island, Five holes cave (22°4.914′ N 121°30.664′ E, 4 m), two females (no. 1895–1, 2) from C. chinense, 4.ix.2016, H. Y. Lin (TARI); Lanyu Island, Lovers cave (22°3.693′ N, 121°34.427′ E, 12 m), one female (no. 1896-1) from C. chinense, 4.ix.2016, H. Y. Lin (ESALQ-USP); three females and eight males (no. 1901-2, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14) data as holotype (NTU); Lanyu Island, Red head rock (22°01.077′ N, 121°35.990′ E, 24 m), one female one male (no. 2064–1, 2) from C. chinense, 4.ix.2016, C. F. Hsu (NCHU).
Etymology
The name crossostephium refers to the host plant Crossostephium chinense (L.) Makino.
Remarks
This new species is similar to T. (A.) acaciae Schultz, 1973, T. (A.) betulae (Kolodochka, 1992), T. (A.) brisbanensis Schicha, 1978, T. (A.) bullatus van der Merwe, 1968, T. (A.) gressitti McMurtry & Moraes, 1985, T. (A.) gutierrezi Blommers, 1973, T. (A.) krimbasi Papadoulis & Emmanouel, 1997, T. (A.)philippinensis Corpuz, 1966, T. (A.) tridentiger Tseng (1975) by having four pairs of pre-anal setae, pre-anal pores present and peritreme extend to setae j1, setae R1 off dorsal shield, 3 teeth on movable digit, st3 on sternal shield, seta Z5 with shovel-shaped end, leg IV with 3 macrosetae. Differences between T. (A). crossostephium sp. nov. and related species are given in Table 1.
T. (A.)philippinensis and T. (A.) tridentiger which seems most close to the new species. The new species differs from T. (A.) philippinensis in the shovel-shaped end of seta Z4 with expanded blade (Z4 shovel-shaped without expanded blade in ph ilippinensis), Z5 smooth (barbed in philippinensis), seta S5 thicker and longer 16 14 (9–18) (8 in philippinensis), relative length of macrosetae St IV > Sge IV > Sti IV (Sge IV > St IV > Sti IV in philippinensis), JV5 with shovel-shaped (JV5 normal in philippinensis), fixed digit with 4 teeth (3 teeth in philippinensis) (Figures 6, 7). These characters are persistent in the two paratypes and four voucher specimens of T. philippinensis we loaned from UPLB-MNH.
Tseng (1975) described T. (A.) tridentiger from Lanyu Island not detailed enough for the subgenus Anthoseius, and all specimens were lost (Liao et al. 2017b). It is impossible to compare the new species to type specimens of T. (A.) tridentiger. However, this new species is similar to T. (A.) tridentiger based on original description of Tseng (1975). The new species differs from T. (A.) tridentiger in seta Z4 with expanded shovel-shaped end (sharp end in tridentiger), fixed digit with 4 teeth (3 teeth in tridentiger), and leg IV without additional macrosetae (with additional macrosetae on Sge IV, Sti IV in tridentiger). We consider Z4 shape and additional macrosetae present/absent on leg IV could confirm they are separated species.
FIGURE 1.
The location where the Typhlodromus (Anthoseius) crossostephium sp. nov. were found. A. Type locality; B. Neighboring rocky shores.
FIGURE 2.
Typhlodromus (Anthoseius) crossostephium sp. nov. female. A. Dorsal shield; B. Ventral idiosoma; C. Chelicera; D. Spermatheca; E. Setae Z5 dorsal and lateral views and seta S2.
FIGURE 3.
Typhlodromus (Anthoseius) crossostephium sp. nov. female, legs. A. Leg I anterior view; B. Leg II dorsal-posterior view; C. Leg III posterior view; D. Leg IV posterior view.
FIGURE 4.
Typhlodromus (Anthoseius) crossostephium sp. nov. male. A. Dorsal shield; B. Ventral idiosoma; C. Chelicera and spermatodactyl.
FIGURE 5.
Typhlodromus (Anthoseius) crossostephium sp. nov. male, legs. A. Leg I anterior view; B. Leg II dorsal-posterior view, C. leg III dorsal-posterior view; D. Leg IV dorsal-posterior view.
TABLE 1.
Differences between Typhlodromus (A.) crossostephium sp. nov. and related species.
(Continued).
FIGURE 6.
Dorsal setae Z4, Z5 , S5. A. Typhlodromus (Anthoseius) crossostephium sp. nov. (female holotype); B. Typhlodromus (Anthoseius) philippinensis Corpuz, 1966 (female paratype Aca025-6).
FIGURE 7.
Macrosetae on leg IV. A. Typhlodromus (Anthoseius) crossostephium sp. nov. (female holotype); B. Typhlodromus (Anthoseius) philippinensis Corpuz, 1966 (female paratype Aca025-6).
Key to Typhlodromus (Anthoseius) species known from Taiwan based on adult females3
1. Ventrianal shield with three pairs of preanal setae transvaalensis
- Ventrianal shield with four pairs of preanal setae 2
2. Preanal pores absent 3
- Preanal pores present 4
3. Sternal shield with two pairs of setae neocrassus
- Sternal shield with three pairs of setae changi
4. Ventrianal shield with small rounded preanal pores ryukyuensis
- Ventrianal shield with crescentic preanal pores 5
5. Sternal shield with two pairs of setae obesus
- Sternal shield with three pairs of setae 6
6. Movable digit of chelicera with one tooth 7
- Movable digit of chelicera with more than one tooth 8
7. Fixed digit of chelicera with one tooth lanyuensis
- Fixed digit of chelicera with four teeth gracilentus
8. Fixed digit of chelicera with seven teeth pseudoserrulatus
- Fixed digit of chelicera with about 3–4 teeth 9
9. Both dorsal setae Z4 and Z5 shovel-shaped end with expanded blade crossostephium sp. nov.
- Only dorsal setae Z4 shovel-shaped end tridentiger
Discussion
In this study, we propose Typhlodromus (Anthoseius) crossostephium sp. nov. as a new taxon for science; this is the first report on phytoseiid species found in rocky shores. Stathakis et al. (2016) surveyed a coastal region, where they found phytoseiids, therefore, we suspected the natural coastal regions may have more undiscovered mite species. We observed the plant C. chinense on rocky shores on coastal line of the Lanyu Island. C. chinense naturally occurs in littoral habitats of Taiwan, Ryukyu Islands, and the Bonin Islands (Hobbs et al. 2013). Taiwanese people generally cultivate this plant at their home, because of its well-known efficacy in Chinese medicine. At present, finding this plant in native habitats is difficult owing to environmental destruction. Although we surveyed coastal regions surrounding the main island of Taiwan, no native C. chinense plants and phytoseiid mites were found. We also surveyed cultivated C. chinense plants, but still no phytoseiid mites were discovered. Thus, we suspected that although phytoseiid mites are strongly associated with their host plant, some other unknown factors also influence their presence; therefore, we could not find these new species on our cultivated C. chinense plants. Thus, further survey of the coastal ecosystem for phytoseiid mites is worth.
Acknowledgements
We thank Y.T. Hsu (TTDARES, Taiwan) and H.Y. Lin (Taiwan) for Lanyu Island collection, C. F. Hsu (NTU, Taiwan) for habitat photos, to H. C. Lee (NTU, Taiwan) for illustration, to Dr. M. J. Yang (NCYU, Taiwan), Y. Hsiao, Dr. J. F. Hsieh, Dr. M. C. Chiu (NTU, Taiwan) for suggestions. Thanks also to Dr. İ. Döker (CU, Turkey) for his encouragement and suggestions for the manuscript, Y. Kendrick and R. Mech for English editing of the draft. We also thank L. A. Corpuz-Raros, J. C. T. Gonzalez and J. Naredo (UPLB-MNH, Philippines) for lending type specimens of T. (A). philippinensis for comparison. The study is supported by grants (MOST 105-2621-B-002-002-MY3) from the Ministry of Science and Technology, Taiwan.
References
Notes
[1] 1. Previous studies described the shape called “knobbed, blunt”. We observed lateral view of setae with transparent ends (e.g. dorsal setae and JV5), and considered the transparent end shaped like shovel, and Z4, Z5 with expanded blade (Fig. 3–E).
