The Genus Tegonotus Nalepa (Acariformes: Eriophyidae: Phyllocoptinae): Description of a New Species and Key to Valid Species ^†

Abstract

The genus Tegonotus Nalepa (Acariformes: Eriophyidae: Phyllocoptinae) is recorded for the first time from Saudi Arabia with the description of a new species, T. saudiensis sp. nov., collected from the inner fronds of Phoenix dactylifera L. (Arecaceae), described and illustrated based on females. The individuals of the new species were vagrant on the abaxial leaf surface, causing no apparent damage to the host plant. The taxonomic status of the genus and its species was thoroughly assessed through the literature-based analysis of morphological characters. Consequently, the diagnosis of the genus Tegonotus is updated, and a key to 47 valid species is provided. Eight Tegonotus species are suggested to be transferred to three different genera within the tribe. A brief discussion on the taxonomic status of these species is provided. The position of scapular tubercles and setae (sc), and shape of the dorsal pedipalp genu seta (d), were found to be significant for the generic designation.

1. Introduction

The date palm (Phoenix dactylifera L.) belongs to the palm family Arecaceae (formerly Palmae) and is distributed throughout the subtropical and tropical regions of the world [1]. Until now, 80 eriophyoid mites have been described from the plants of the family Arecaceae, including two Tegonotus Nalepa species: T. gutierrezi Boczek et Natcheff, and T. larii Kamali, Majidi et Akrami (Amrine and de Lillo, unpublished eriophyoid database).

Tegonotus is the type genus of the tribe Tegonotini (Acariformes: Eriophyidae: Phyllocoptinae) [2,3], considered as the second largest genus in the tribe, and currently includes 58 species, distributed in Oriental, Palearctic, and Tropical regions of the world (Amrine and de Lillo unpublished eriophyoid database) [4,5]. Some Tegonotus species have economic importance for agronomic crops, i.e., Sweet potato rust mite, T. convolvuli (Channabasavanna) [6]. Until now, most of the published papers on the species of genus Tegonotus are regional, including identification keys from China and India [7,8]. The genus Tegonotus was erected based on the type species, Acanthonotus heptacanthus Nalepa [9], distinguished from the closely related genus Shevtchenkella Bagdasarian by the position of scapular setae (sc), which is well ahead of the rear shield margin in Tegonotus and on the rear shield margin in Shevtchenkella [3,9].

Previously, thirty-three species were transferred from Tegonotus to different genera of the tribe Tegonotini and even to other tribes of the subfamily Phyllocoptinae [10,11,12,13]. Twenty-six species were moved to four genera of the tribe Tegonotini. Among them, Amrine and Stasny [11] assigned twenty-one species to Shevtchenkella, entirely based on the published literature. Three species were considered as the type species of Khanthongella Chandrapatya, Konvipasruang et Amrine, Neotegonotus Newkirk et Keifer, and Vareeboona Chandrapatya, Konvipasruang et Amrine [10,13]. The scapular setae (sc) position and the pedipalp genu seta (d) state were considered as significant generic characters to transfer species or even to erect new genera [13]. However, there are some species described under the genus Tegonotus that should be reconsidered for their generic assignment and require a comprehensive taxonomic assessment.

Since the last comprehensive review of the superfamily Eriophyoidea by Amrine et al. [3], 15 monotypic genera have been established, making a total of 40 genera in the tribe Tegonotini [13,14,15,16,17,18]. This addition of a huge number of genera has also raised concerns about the dilution of the significance of morphological characters at the genus level within the tribe. It is important to update the morphological diagnosis of the genus Tegonotus, and to evaluate its species for their valid generic designation based on the most recently described genera within the Tegonotini.

The aims of the present research were to describe a new Tegonotus species, T. saudiensis sp. nov., collected from P. dactylifera, to assess the significance of generic diagnostic characters of Tegonotus, to comprehend the generic assignment of all Tegonotus species and to develop a diagnostic key to known Tegonotus species.

2. Materials and Methods

The published taxonomic literature of all Tegonotus species was collected through different resources, i.e., personal communication with different global eriophyoidologists, through keyword searches on multiple search engines (i.e., Research Gate, Google, etc.), and websites including those of acarological and entomological research journals. The original and subsequent diagnoses of each Tegonotus species, as well as published regional keys, were critically studied to prepare the current diagnostic key.

Furthermore, the mite collection trips were organized occasionally during 2022–2024 to the northern parts of AlMedina AlMunawarah province (Saudi Arabia), generally to explore the regional mite fauna, including eriophyoid mite collection as a part of it. Different foliage (especially inner fronds) of P. dactylifera (Arecaceae) were snipped and placed in field-labelled polythene bags, along with paper towels, and stored in the icebox. Mite specimens were collected, both directly from foliage under a dissecting stereomicroscope and by the modified washing method, following Monfreda et al. [19]. The collected specimens were cleared in lactic acid at room temperature and mounted in Keifer’s F-medium [20], as updated by de Lillo et al. [21]. The morphological terminology and setal notation follow Lindquist [18]. The genus of the new species was identified by following the generic key of Amrine et al. [3] and diagnoses of 15 genera established since 2003. The new species was identified based on the key to Tegonotus species provided in the present study. Different body parts were imaged by using an Auto-Montage Pro software (v. 5.04.0072, Syncroscopy, Cambridge, UK,) attached to the compound microscope (DM2500, Leica^®, Wetzlar, Germany). Some body parts were hand-drawn with a drawing tube (Camera Lucida) attached to the Olympus microscope (BX51, Olympus^®, Tokyo, Japan). These were used as a template for the schematic line drawings, drawn with Adobe Illustrator (Adobe Systems Inc., San Jose, CA, USA). The morphological traits were measured by following Lindquist [22], as modified by de Lillo et al. [21]. All measurements are given in micrometers (μm). The holotype’s measurements are followed by the range values of the paratypes in parentheses. The measurements were rounded off to the nearest integer, and are regarded as the length of the morphological traits unless otherwise specified. The plant samples were identified from the Department of Botany at the College of Science, King Saud University (KSU). All collected specimens, along with holotypes and paratypes of new species, were deposited at the King Saud University Museum of Arthropods (KSMA, Acarology section), Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.

3. Results

After a comprehensive literature-based taxonomic review of all (58) Tegonotus species, the diagnosis of the genus was updated. Also, six species, viz., T. ferruginiae Mohanasundaram, T. schleicherae Ghosh et Chakrabarti, T. toxicodendronis Kuang et Hong, T. fisus Chakrabarti et Sarkar, T. dubrakoni Ghosh et Chakrabarti, and T. litseae Ghosh et Chakrabarti, do not correspond with the diagnostic characters of the genus Tegonotus. They were found to be described with the scapular tubercles and setae (sc) present on the rear margin of the prodorsal shield, while in two species, T. castanopsis Wei, Li et Wang and T. fragariae Boczek et Petanovic, the scapular tubercles and setae (sc) present near the rear margin of the shield. Both of these character states do not correspond with the updated diagnosis of Tegonotus, and hence those eight species are suggested to be transferred to other related genera (Table 1). The taxonomic notes and a brief discussion of their transfer to related genera is provided. The validity and taxonomic notes on two species, T. canaris Xu, Chen et Xue and T. keiferi (Farkas), are discussed in detail. A new species of Tegonotus from Saudi Arabia, and a diagnostic key for valid species is provided too.

Family Eriophyidae Nalepa

Subfamily Phyllocoptinae Nalepa

Tribe Tegonotini Bagdasarian

Genus Tegonotus Nalepa

Type species: Acanthonotus heptacanthus Nalepa

3.1. Updated Diagnosis

Dorsal scapular tubercles and setae (sc) situated well ahead of rear shield margin of prodorsal shield, directed up, inward or outward, pedipalp genu dorsal setae (d) unfurcated, all or some opisthosomal semiannuli laterally either with prominent pointed or rounded projections, opisthosomal setae (c₂, d, e, f) always present, setae h₁ present or absent, and seta on leg tibia I and genu II either present or absent.

3.2. New Species

3.2.1. Tegonotus saudiensis sp. nov.

Diagnosis: Prodorsal shield with broad base frontal lobe, entirely without granules, median line absent, admedian lines short on the posterior 1/3, connected by a transverse line anteriorly, tubercles of scapular setae (sc) ahead of rear shield margin with longitudinal basal axes, setae (sc) directed inward, all dorsal opisthosomal semiannuli smooth, ventral semiannuli with rounded microtubercles, coxisternal plates with irregular short lines, female genital coverflap with one row of longitudinal striae.

Description: Female (n = 10): body fusiform, 157 (155–160) without gnathosoma, 52 (50–55) wide, 46 (44–48) thick, light yellow. Gnathosoma 19 (17–21), projecting obliquely downwards, cheliceral stylets 19 (17–21), pedipalp coxal seta simple (ep) 4 (3–5), dorsal pedipalp genu setae (d) 7 (6–8), unfurcated, palp tarsal ventral setae (v) indistinct. Prodorsal shield subtriangular, 48 (45–50) (including the broad-based frontal lobe), 52 (50–55) wide, entirely without granules, median lines absent, admedian lines short, on the posterior 1/3 of the shield connected anteriorly by a transverse line, transverse line indiscernible in lateral view and submedian lines present on sub-lateral surface of the prodorsal shield (Figure 1 D); scapular tubercles (sc) ahead of rear shield margin, basal axes longitudinal, scapular setae (sc) 5 (4–6), 18 (16–19) apart, directed upward and inward (Figure 1 D and Figure 2). Coxisternal plates with irregular short lines, sternal line short, 5–6 semiannuli between coxal plate and genital region, all three pairs of coxal setae present, anterolateral setae on coxisternum I (1b) 7 (6–7), 12 (11–13) apart; proximal setae on coxisternum I (1a) 20 (19–22), 9 (8–10) apart; proximal setae on coxisternum II (2a) 32 (30–35), 20 (19–22) apart. Legs with all usual segments and setae. Leg I 32 (30–33), trochanter 3 (2–4), femur 10 (8–12), genu 4 (4–5), tibia 8 (7–9), tarsus 5 (4–6), tarsal empodium (em) simple, 4 (3–5), 4-rayed (Figure 3C), tarsal solenidion (ω) 7 (6–7), distally with large spherical knob; basiventral femoral setae (bv) 12 (10–13); antaxial genual setae (l″) 13 (11–15); paraxial tibial setae (l′) 4 (3–5), located at basal 1/3 of tibia; paraxial fastigial tarsal setae (ft′) 16 (15–17), antaxial fastigial tarsal setae (ft″) 17 (16–18), paraxial unguinal tarsal setae (u′) 3 (3–4) (Figure 3A). Leg II 27 (26–30), trochanter 2 (2–3), femur 9 (8–9), genua 5 (4–5), tibiae 6 (5–6), tarsi 7 (6–7), tarsal solenidion (ω) 8 (7–8) distally knobbed, tarsal empodium simple, 4 (3–5), 4–rayed; basiventral femoral setae (bv) 11 (10–12); antaxial genual setae (l″) 4 (4–5); paraxial fastigial tarsal setae (ft′) 5 (5–6), antaxial fastigial tarsal setae (ft″) 18 (17–20), paraxial unguinal tarsal setae (u′) 3 (2–3) (Figure 3B). Opisthosoma with dorsally broad smooth semiannuli 30 (27–32) projecting laterally as broad clear rounded processes, first five dorsal semiannuli compressed, ventrally 58 (55–62) semiannuli (counted from first annulus after coxae II), with rounded microtubercles, the last four ventral semiannuli with linear microtubercles (Figure 1). Lateral setae (c₂) 12 (10–14), on ventral semiannulus 9 from coxae II, 40 (38–42) apart; setae (d) 25 (23–28), on semiannulus 17 (17–18), 21 (20–22) apart; setae (e) 8 (7–9), on semiannulus 35 (32–38), 9 (8–10) apart; setae (f) 21 (20–23), on the 6th ventral semiannulus from rear, 13 (11–15) apart; caudal setae (h₂) 42 (40–47); accessory setae (h₁) 4 (3–5) (Figure 2). Female external genitalia 16 (14–17), 19 (18–20) wide, coverflap with 10 (8–12) longitudinal striae, in one series, proximal setae (3a) 12 (11–14), 15 (14–16) apart (Figure 3E). Internal genitalia: spermathecae ovoid, oriented posterolateral, spermathecal tubes relatively short, directed postero-laterally, transverse genital apodeme trapezoidal (Figure 3D).

Male: no males were found in the inspected populations. However, the new species has been collected from the same host plant species in two different localities and at different times. This may reflect its close association with P. dactylifera L. (Arecaceae).

Etymology: the name of the new species (saudiensis) refers to the name of the country, ‘‘Saudi Arabia’’, where the type specimens were collected.

Type material: holotype female (KSMAAS-23-Eri-Teg-H), and six paratype females (KSMAAS-23-Eri-Teg-P1-6), from inner fronds of P. dactylifera, AlMedina AlMunawwara, Saudi Arabia, 24°26′51.7″ N 39°37′55.8″ E, elevation 1300 m, 11 March 2023, coll. Eid M. Khan. Three paratype females (KSMAAS-24-Eri-Teg-P7-9), from inner fronds of P. dactylifera, Basita, Jouf, Saudi Arabia, 30°14′47.7″ N 38°14′58.6″ E, elevation 640 m, 17, September, 2024, coll. Eid M. Khan.

Relation to the host plant: vagrant on the abaxial surface of leaves. No apparent symptoms on the host foliage were observed.

Remarks: Tegonotus saudiensis sp. nov. is morphologically close to T. larii Kamali, Majidi et Akrami [23] and T. tricarinatus Flechtmann [24] by having accessory setae h1, no median line, prodorsal shield without granules and a four-rayed empodium. However, the new species differs from T. larii by the ornamentation on coxisternal plates (with short irregular lines in T. saudiensis sp. nov. vs. without ornamentation in T. larii), admedian lines (short vs. complete), the connection between admedian lines (transverse line vs. without transverse line) and submedian lines (present on lateral margin vs. absence of submedian line). The new species differs from T. tricarinatus by opisthosomal dorsal semiannuli organization (without ridges in T. saudiensis sp. nov. vs. three longitudinal ridges in T. tricarinatus), first dorsal semiannulus (first five annuli are compressed vs. first dorsal semiannulus twice long as each subsequent one), and the connection between admedian lines (transverse line vs. without transverse line).

3.2.2. Identification Key for the Species of the Genus Tegonotus (47 Species)

There were 58 Tegonotus species reported throughout the world. A total of 47 species (including new species) are presented in the current key. Among the remaining eleven species, eight are proposed to be transferred to three different genera of the tribe Tegonotini. Meanwhile, four species (T. doctersi (Nalepa), T. lepidonotus Nalepa, T. leeuweni Newkirk, and T. platynaspis (Nalepa), although they are valid, were not included in the key due to a lack of sufficient characters in their original descriptions.

1.

Setae h1 absent……………………………………..…..………..………………………..…2

-

Setae h1 present…………………………………..……………..…………………….…...21

2.

Female genital cover flap without striae…………………………….................................3

-

Female genital cover flap with striae…….………………….…………..………………...4

3.

Opisthosomal dorsal semiannuli laterally with prominent pointed projections ……………………………………………………………………….....T. trouessarti Nalepa

-

Opisthosomal dorsal semiannuli laterally with rounded lobe-like projections…………………………………………………………...T. actinidiae Wei, Wang et Li

4.

Female genital cover flap with a single row of striae………………….………...……...8

-

Female genital cover flap with two rows of striae……………………………….……….5

5.

Coxisternal plates smooth………………..….T. bhutanensis Chakrabarti et Chakrabarti

-

Coxisternal plates with lines/small dashes…………………………………..…………...6

6.

Prodorsal shield with only admedian lines……………………………………………….. ………………………………………..T. caricus Elhalawany, Mohamed, et Ueckermann

-

Prodorsal shield with median and submedian broken lines ……………………..……7

7.

Anterior and lateral edges of prodorsal shield granulates…………………………… ………………………………………………T. microcarpa Ren, Guan, Tan, Yang et Wang

-

Anterior and lateral edges of prodorsal shield without granules…………………….……………………………………………………………………….T. camphori (Barké et Davis)

8.

Opisthosomal dorsal semiannuli laterally with prominent pointed projections……9

-

Opisthosomal dorsal semiannuli laterally with prominent rounded projection…….10

9.

Prodorsal shield with three small spines on anterior margin of frontal lobe, empodium 7-rayed……………………………………………T. gutierrezi Boczek et Natcheff

-

Prodorsal shield without spines on anterior margin of frontal lobe, empodium 4-rayed……………………………………………………………….T. acutilobus (Nalepa)

10.

Prodorsal shield with depressed hollow pattern or complete network of cells……...11

-

Prodorsal shield with lines…………………………………….....………………………12

11.

Prodorsal shield with depressed hollow pattern, seta on genu II present…………... …………………………………………………………………..T. canaris Xu, Chen et Xue

-

Prodorsal shield with complete network of cells, seta on genu II absent….............… ……………………………………………………………….T. bassius Das et Chakrabarti

12.

Prodorsal shield with many irregular broken lines..……….......T. beihaiensis Wei et Xie

-

Prodorsal shield with prominent median, or admedian or submedian lines………. 13

13.

Prodorsal shield with median line………..…………..……….…..….……………..…...14

-

Prodorsal shield without median line…………………………...……............................15

14.

Coxisternal plates with lines; empodium 5-rayed……………......................………….. ……………………………………………………..T. paramangiferae Huang, An et Huang

-

Coxisternal plates without lines, empodium 6-rayed…..............................……………. ……………………………………………..T. jambolensis Mondal, Ghosh et Chakrabarti

15.

Admedian lines of the prodorsal shield medially connected by a transverse line...... ……………………………………………………………T. albus Xue, Han, Song et Hong

-

Admedian lines of the prodorsal shield not medially connected by a transverse line………….........................................................................................................................16

16.

Coxisternal plates with granules or lines…….………..……..………………………… 17

-

Coxisternal plates without granules or lines………..……………..……………...........19

17.

Prodorsal shield with admedian lines curvy, anterior and lateral edges of prodorsal shield with granules…………………………………………………….T. streblusi Boczek

-

Prodorsal shield with admedian or submedian lines straight, anterior and lateral edges of prodorsal shield without granules …………………………………………...18

18.

Submedian line absent, admedian line very short, from basal 1/5 to 2/5…………….. …………………………………………………………………..T. exiguus Huang et Wang

-

Submedian line present, long and branched near the dorsal tubercle………………… ……………………………………………………….T. bengalensis Mondal et Chakrabarti

19.

Empodium 7-rayed…………………………………………….T. similis Wang et Huang

-

Empodium 5-rayed……………………………………………………………………….20

20.

Prodorsal shield with lateral submedian line, running parallel to the lateral side of the shield…………………………………..………………….T. tinctoriae Wei, Wang et Li

-

Prodorsal shield without lateral submedian lines….T. caryophyllatus Huang et Cheng

21.

Prodorsal shield anterior frontal lobe emarginated/notched………..T. keiferi (Farkas)

-

Prodorsal shield anterior frontal lobe not emarginated/rounded……………………22

22.

A deep cleft between prodorsal shield and opisthosoma, first semiannuli large and projecting higher than other annuli……………………………………T. collaris Nalepa

-

Prodorsal shield and opisthosoma not separated by a deep cleft, first semiannuli not enlarged………..………………..………………………………………………………….23

23.

Opisthosomal semiannuli laterally with prominent pointed projections……………41

-

Opisthosomal semiannuli laterally with rounded lobes……………………………….24

24.

Prodorsal shield with lines………….....………..……..……………...………………….26

-

Prodorsal shield without lines.…..…..…………………………………………………..25

25.

Prodorsal shield entirely granulated…………………………………..T. halleriae Meyer

-

Prodorsal shield entirely smooth…………………………….T. buergeriani Kuang et Lin

26.

Opisthosoma with first eight dorsal semiannuli broad……..T. montanus Hu et Krantz

-

Opisthosoma all dorsal semiannuli of similar size…………………………………….27

27.

Prodorsal shield with many irregular broken lines………………T. septentrionalis Liro

-

Prodorsal shield with median or admedian, or submedian lines……...…….………28

28.

Prodorsal shield with median line……………………………………………..…...……29

-

Prodorsal shield without median line………………………………...………..…..…....32

29.

Median lines complete, empodium 4-rayed......................T. hispidae Wang, Wei et Yang

-

Median line incomplete; empodium more than 4-rayed……………….……………..30

30.

Prodorsal shield laterally granulated………………T. exbucklandia Wang, Tan et Yang

-

Prodorsal shield laterally without granule……………………………………………..31

31.

Coxisternal plates smooth, admedian line incomplete…..T. carpathicus Lewandowski

-

Coxisternal plates with granules, admedian line complete …………………………… …………………………………………………………...T. parabaenae Wang, Tan et Yang.

32.

Prodorsal shield lines forming a network of cells…………T. fabris Han, Xue et Hong.

-

Prodorsal shield without network of cells……………………………………………..33

33.

Prodorsal shield with granules…………..………………………………T. borealis (Liro)

-

Prodorsal shield without granules ………..…………………..………………………..34

34.

Coxisternal plates with granules or lines………………………………………………39

-

Coxisternal plates smooth……………………………………………………………….35

35.

Female genital coverflap indistinct/without striae……………………………………36

-

Female genital coverflap with distinct striae…………………………………………..37

36.

Prodorsal shield frontal lobe anteriorly triangular, empodium 4-rayed……………… …………………………………………………………………………T. scoticus Roivainen

-

Prodorsal shield frontal lobe anteriorly broad rounded, empodium 6-rayed……….. ……………………………………………………………………………T. abietis Bagnyuk

37.

Frontal lobe of prodorsal shield anteriorly emarginated/notched…………………….. …………………………………………………………….T. adamasimilis Wang et Huang

-

Frontal lobe of prodorsal shield anteriorly broad rounded………………………….38

38.

Opisthosomal dorsal semiannuli with filamentous microtubercles, empodium 6-rayed, admedian short at the base…………………………T. pini Wang, Tang et Yang

-

Opisthosomal dorsal semiannuli smooth, empodium 4-rayed, admedian complete…………………………………………………….T. larii Kamali, Majidi et Akrami

39.

Female genital cover flap with single row of striae…………………………………….40

-

Female genital cover flap with two rows of striae….T. convolvuli (Channa Basavanna)

40.

Opisthosomal dorsal semiannuli without ridges, admedian line connected by a transverse line………………………………………………………………T. saudiensis sp. nov.

-

Opisthosomal dorsal semiannuli with longitudinal ridges, admedian line not connected by a transverse line……………………………………T. tricarinatus Flechtmann

41.

Prodorsal shield with granules…………………………………………………………..42

-

Prodorsal shield without granules……………………….………..……….……..……..44

42.

Opisthosomal dorsal semiannuli laterally with alternative projection, prodorsal shield only laterally, with few granules…………………………….T. uranomus (Keifer)

-

Opisthosomal dorsal semiannuli laterally with equally expanded projection, prodorsal shield medially and laterally with many granules…………………………………43

43.

Opisthosomal dorsal semiannuli with median ridges, coxisternal plates smooth…………………………………………………………….T. heptacanthus (Nalepa)

-

Opisthosomal dorsal semiannuli with furrow; coxisternal plates granulated ………………………………………………………….T. platycaryanis Song, Xue et Hong

44.

Frontal lobe of prodorsal shield anteriorly spear-shaped…………...T. occidens (Keifer)

-

Frontal lobe of prodorsal shield anteriorly broad, rounded………………………….45

45.

Opisthosomal dorsal semiannuli laterally with alternative pointed projections; empodium 3-rayed………………………………………………………….T. eupators Huang

-

Opisthosomal dorsal semiannuli laterally with equally expanded projections; empodium 4- or 5-rayed…………………………………………………………………………46

46.

Empodium 5-rayed ………...............................…….T. ecovagrans (Flechtmann et Davis)

-

Empodium 4-rayed………………….…………................................T. depressus (Nalepa)

Notes on the generic status of eight transferred Tegonotus species

Tegonotus ferruginiae was originally described with the scapular tubercles and setae (sc) present on the rear margin of the prodorsal shield [25]. The Amrine and de Lillo unpublished eriophyoid database refers to the designation of this species to the genus Tegonotus, based on the direction of the scapular (sc) setae. The description and illustration reported neither the absence/presence of genu II seta, nor the dorsal pedipalp genu setal (d) shape. This character state requires further investigation for its significance for generic designation. Meanwhile, this species, with the available information, could be transferred to either Shevtchenkella or Scolotosus Flechtmann et De Queiroz. Due to absence of spines on dorsal semiannuli, it is closely related to the genus Shevtchenkella.

Similarly, T. toxicodendronis, T. castanopsis and T. fragariae, were described with the scapular tubercles and setae (sc) placed on or near the rear margin of the prodorsal shield, the presence of seta on leg tibia I and genu II, dorsal pedipalp genu seta (d) unfurcated and all coxae setae present [26,27,28]. Based on these morphological characters, these three species are suggested to be transferred to the Shevtchenkella.

Tegonotus fisus was described and illustrated with a bifurcated dorsal pedipalp genu seta (d) and lacking seta on tibia I [29]. Later on, the genus Vareeboona was established, based on the type species, V. mangiferae (Keifer), provided with the pedipalp genu seta (d) bifurcated [13]. Hence, T. fisus is proposed to be assigned to the monotypic genus Vareeboona. This species also shares the same host plant (Mangifera indica (L.) (Anacardiaceae)) and country (India) as that of V. mangiferae. Additionally, all morphological characteristics of both species suggest, T. fisus as the junior synonym of V. mangiferae.

Three species of Tegonotus, T. schleicherae, T. dubrakoni and T. litseae were originally described with the scapular tubercles and setae (sc) present on the rear margin of the prodorsal shield, with the presence of seta on tibia I and absence of seta on genu II [7,30]. The character of accessory setae h1 of T. schleicherae was described ambiguously as “may be present” [7]. It is suggested that these species be transferred to the genus Neoshevtchenkella. However, there is a concern over the validity of T. dubrakoni. It was described in a research thesis and is not available through any research paper published in a scientific journal.

Notes on the validity of two Tegonotus species

Tegonotus canaris was distinguished from all species of the genus, based on the presence of divided empodium and depressed hollows pattern on the prodorsal shield [31]. The divided empodium conflicts with the character state of the Tribe Tegonotini. This brought concerns over the tribal validity of T. canaris. The divided empodium differentiates the tribe Acaricalini from other four tribes in the family Phyllocoptinae [3]. In contrast, Xu et al. [31] provided a detailed argument for the phylogenetic significance of the empodium character and referred to the findings of Li et al. [32], who made a detailed molecular-based phylogenetic analysis. They conclude that the character of empodium (divided or entire) has independently evolved multiple times, rejecting the monophyly of four out of five tribes of the subfamily Phyllocoptinae, including Tegonotini. Additionally, Xu et al. [31] supported the assignment of T. canaris to Tegonotini by stating examples of divided empodium in species of the genus Notostrix Keifer in the tribe Anthocoptini [32]. Therefore, in the present study, the status of T. canaris is considered valid in the genus Tegonotus, owing to the findings of Li et al. [32] and Xu et al. [31], and has been differentiated in the presented key from closely related species by avoiding using the empodium character.

Tegonotus keiferi (Farkas) was originally described in the genus Oxypleurites [33], which was transferred to the genus Tegonotus [11]. In the Amrine and de Lillo unpublished eriophyoid database, T. keiferi has been commented on as invalid, but no taxonomic reasons were provided. In the original description, T. keiferi was differentiated from all species of the genus Oxypleurites, based on the state of frontal lobes (laterally illustrated as emarginated, and the shape of tergites (long-winged) [33]. Based on the updated diagnosis of the genus Tegonotus in the present study, T. keiferi is considered valid, due to the presence of scapular tubercles and setae (sc) well ahead of the prodorsal shield rear margin, directed upward, and the dorsal semiannuli with pointed (long-winged) projections. The original description provided is brief, and the illustrations lack necessary details; hence, the morphological characters of pedipalp genu dorsal setae and those of leg setation should be clarified through re-description from the type specimen.

In conclusion, eight Tegonotus species are hereby suggested to be reassigned to three genera, through a literature-based analysis of diagnostic generic characters. Among the significant morphological characters considered in the current proposal, the position of scapular tubercles and setae (sc) an the shape of the pedipalp genu seta (d) are considered as significant generic characteristics. In future research, morphology and molecular-based phylogenetic research may prove the significance of the absence or presence of seta on leg tibia I and genu II for possible divisions of existing taxonomic ranks.

Table 1. Tegonotus species suggested for transfer to the respective genera.

Species	Type Host	Type Country	Diagnostic Characters of the Genus Transferred	Comments
Tegonotus castanopsis [27]	Castanopsis eyrei (Champ. et Benth.) Tutcher (Fagaceae)	Hungary	Scapular tubercles and setae (sc) are located on the rear shield marginŠ	It is suggested that four Tegonotus species be assigned to the genus Shevtchenkella, based on the consistent generic characteristics, i.e., scapular tubercles and setae (sc) on or near the rear shield margin, found in their descriptions and illustrations. Shevtchenkella is the largest genus in Tegonotini, consisting of more than 85 species. Currently, it is difficult to propose a possible synonym or a closely related species for each species.
T. fragariae [28]	Fragaria sp. (Rosaceae)	Serbia
Tegonotus ferruginiae [25]	Acacia ferruginea DC. (Fabaceae)	India
Tegonotus toxicodendronis [26]	Toxicodendron succedaneum (L.) Kuntze (Anacardiaceae)	China
Tegonotus dubrakoni [30]	Unknown host	India	Scapular tubercles and setae (sc) set on the rear shield margin, lack of seta on genu II.	These three species have scapular tubercles and setae (sc) located on the rear shield margin, and are lacking seta on genu II. Considering other shared generic morphological characteristics, it is suggested that these three species be assigned to Neoshevtchenkella.
Tegonotus schleicherae [7]	Schleichera oleosa (Lour.) Oken (Sapindaceae)	India
Tegonotus litseae [7]	Litsea sp. (Lauraceae)	India
Tegonotus fisus [29]	Mangifera indica L. (Anacardiaceae)	India	Dorsal pedipalp genu seta (d) bifurcated.	Tegonotus fisus was described and illustrated with a bifurcated pedipalp genu seta (d), and was reported from M. indica (L.) (Anacardiaceae). The morphological characters of this species corresponds to the monotypic genus Vareeboona. Moreover, all morphological characteristics aligned to V. mangiferae (Keifer), which is reported on the same host plant, and widely distributed over the world. It is suggested that this species be transferred to Vareeboona, and proposed as junior synonym of V. mangiferae (Keifer).

Table 1. Tegonotus species suggested for transfer to the respective genera.

Species	Type Host	Type Country	Diagnostic Characters of the Genus Transferred	Comments
Tegonotus castanopsis [27]	Castanopsis eyrei (Champ. et Benth.) Tutcher (Fagaceae)	Hungary	Scapular tubercles and setae (sc) are located on the rear shield marginŠ	It is suggested that four Tegonotus species be assigned to the genus Shevtchenkella, based on the consistent generic characteristics, i.e., scapular tubercles and setae (sc) on or near the rear shield margin, found in their descriptions and illustrations. Shevtchenkella is the largest genus in Tegonotini, consisting of more than 85 species. Currently, it is difficult to propose a possible synonym or a closely related species for each species.
T. fragariae [28]	Fragaria sp. (Rosaceae)	Serbia
Tegonotus ferruginiae [25]	Acacia ferruginea DC. (Fabaceae)	India
Tegonotus toxicodendronis [26]	Toxicodendron succedaneum (L.) Kuntze (Anacardiaceae)	China
Tegonotus dubrakoni [30]	Unknown host	India	Scapular tubercles and setae (sc) set on the rear shield margin, lack of seta on genu II.	These three species have scapular tubercles and setae (sc) located on the rear shield margin, and are lacking seta on genu II. Considering other shared generic morphological characteristics, it is suggested that these three species be assigned to Neoshevtchenkella.
Tegonotus schleicherae [7]	Schleichera oleosa (Lour.) Oken (Sapindaceae)	India
Tegonotus litseae [7]	Litsea sp. (Lauraceae)	India
Tegonotus fisus [29]	Mangifera indica L. (Anacardiaceae)	India	Dorsal pedipalp genu seta (d) bifurcated.	Tegonotus fisus was described and illustrated with a bifurcated pedipalp genu seta (d), and was reported from M. indica (L.) (Anacardiaceae). The morphological characters of this species corresponds to the monotypic genus Vareeboona. Moreover, all morphological characteristics aligned to V. mangiferae (Keifer), which is reported on the same host plant, and widely distributed over the world. It is suggested that this species be transferred to Vareeboona, and proposed as junior synonym of V. mangiferae (Keifer).