# Description of a new species of spider mite of the genus Tetranychus Dufour (Acari: Tetranychidae) from Peru

Hector Alonso Escobar-Garcia, Daniel Júnior de Andrade, Jennifer J Beard, Ronald Ochoa

► To cite this version:

Hector Alonso Escobar-Garcia, Daniel Júnior de Andrade, Jennifer J Beard, Ronald Ochoa. Descrip-
tion of a new species of spider mite of the genus Tetranychus Dufour (Acari: Tetranychidae) from
Peru. Acarologia, 2023, 63 (4), pp.1017-1029. 10.24349/g1e1-1e78. hal-04227977

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# Description of a new species of spider mite of the genus *Tetranychus* Dufour (Acari: Tetranychidae) from Peru

Hector Alonso Escobar-Garcia ID a,b, Daniel Júnior de Andrade ID b, Jennifer J. Beard ID c, Ronald Ochoa ID d

## Original research

### ABSTRACT

A new species of spider mite, *Tetranychus algarrobus* n. sp., is described and illustrated from Peru. It was found damaging the foliage of the native forest tree *Neltuma piurensis* (Fabaceae) in Piura, northwestern Peru.

**Keywords** Tetranychoidea; taxonomy mites; phytophagous mite; algarrobo; forest tree

**Zoobank** http://zoobank.org/47360251-D073-4840-ADFB-BBB2069EE8AA

## Introduction

The family Tetranychidae Donnadieu 1875, commonly known as spider mites, represents one of the most studied groups of all the Acari, mostly due to their economic importance. However, despite this attention, species identification continues to remain a challenge and many important taxa need updated redescriptions. With the family currently comprising 1,345 valid species (Migeon & Dorkeld 2023) and increasing, the need for modern detailed descriptions and diagnostics is becoming critical.

The genus *Tetranychus* Dufour 1832, is one of the largest genera in the family, comprising 153 species worldwide, of which only nine are known to be present in Peru (Escobar-Garcia & Andrade 2021; Migeon & Dorkeld 2023). Recently, a species of *Tetranychus* was detected damaging the foliage of a native forest tree called algarrobo, *Neltuma piurensis* (L. Vásquez, Escurra & Huamán) C.E. Hughes & G.P. Lewis (Fabaceae; previously *Prosopis*) (Hughes *et al.* 2022). Algarrobo, like other related species in the genera *Neltuma* and *Prosopis*, is a tree of economic, ecological, and social importance, with multiple benefits (including nutritional properties), since leaves, fruits, and seeds serve as an important source of high protein food for animals; the fruits and their derivatives known as “algarrobina” are also consumed by humans in Piura of northwestern Peru (SERFOR 2021). The wood of these trees is known for its hardness, stability and preservation and is used not only in carpentry and furniture, but also as a source of long-burning firewood and charcoal production (Depenthal & Yoder 2018; SERFOR 2021; Joseau *et al.* 2023). This recently detected mite is herein described as a new species, *T. algarrobus* n. sp.

Received 04 May 2023
Accepted 11 August 2023
Published 05 September 2023

Corresponding author
Hector Alonso Escobar-Garcia ID:
hescobarg@unp.edu.pe

Academic editor
Auger, Philippe

https://doi.org/10.24349/g1e1-1e78

ISSN 0044-586X (print)
ISSN 2107-7207 (electronic)

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Escobar-Garcia H. A. et al.

Licensed under
Creative Commons CC-BY 4.0

OPEN ACCESS

<footnote>a Facultad de Agronomia, Universidad Nacional de Piura (UNP), Piura, Peru.</footnote>

<footnote>b College of Agricultural and Veterinary Sciences, São Paulo State University (FCAV/UNESP), São Paulo, Brazil.</footnote>

<footnote>c Queensland Museum, P.O. Box 3300, South Brisbane, Qld 4101, Australia.</footnote>

<footnote>d Systematic Entomology Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD20705, USA.</footnote>
**Material and methods**

Mite-infested leaves were collected randomly from the lower third of *Neltuma piurensis* trees
directly into paper bags and transferred to the laboratory for processing. After that, all adult
mites (female and male) were extracted with a fine brush under the stereomicroscope (ZEISS
Stemi 508). The mites were then mounted on slides in Hoyer's medium, heated in an oven
at 50 °C for 7 days (Walter and Krantz 2009) and finally sealed with varnish. Mites were
examined and measured under a Nikon Eclipse E200 phase-contrast compound microscope.
All measurements are given in µm; setal measurements are presented as the range for all
specimens followed by the value for the holotype (when measured) in square brackets. Setae
were measured from the center of the setal base to the tip of the seta; distances between setae
(including solenidion and duplex) were measured as the distance from the center of one setal
base to the other. Leg setal counts are presented as the total number of phaneres followed by
the number of solenidia. The nomenclature for leg setation and for the idiosomal setae follows
that of Lindquist (1985). Male aedeagal parameters follow Reck (1959) and Beard (2008),
except measurement "d" is slightly altered (Figure 1), in addition to the length of the knob and
neck. Images were taken with either a Nikon Eclipse 80i with Capture 2.3 imaging software or
a Zeiss Axioscope AX10 Lab.A1 phase-contrast compound microscope. The type material is
deposited in UNP-Acarology collection of the Entomology Laboratory (SL01LA68), at the
Universidad Nacional de Piura, Peru; and QM-Queensland Museum, PO Box 3300, South
Brisbane, Queensland 4101, Australia.

<figure><img src="image_8.png" /><figcaption>**Figure 1** Measurements used for the description of the male aedeagus as outlined in Methods, "a" full height of aedeagus from ventral margin of shaft to dorsal margin of knob; "b" length of sclerotised dorsal margin of aedeagus, "c" height of shaft between ventral margin and dorsal margin, "d" full length of aedeagus including the often difficult to discern and unsclerotised "stalk" (sensu Reck 1959).</figcaption></figure>

Family Tetranychidae Donnadieu, 1875

Subfamily Tetranychinae Berlese, 1913

Tribe Tetranychini Reck, 1950

Tetranychus Dufour, 1832

Tetranychus algarrobus Escobar-Garcia, Beard & Ochoa n. sp.

Zoobank: D9C6DF8C-71B9-4740-A308-821AA8063CAE

(Figs. 1–11)
**Material examined**

**Holotype** — Male, Peru, campus of the Universidad Nacional de Piura, 05°10'46.89"S, 80°37'04.31"W, 34 m.a.s.l., ex. algarrobo *Neltuma piurensis* (Fabaceae), 10.v.2021, Hector Escobar (SL01LA68).

**Paratypes** — 23 males, 21 females, same data as holotype, except collected between 08.vi.2020–07.vi.2021 (SL01LA68); 2 males, 5 females, same data as holotype, except collected between 22.vi.2020–01.iii.2021 (QM).

**Diagnosis**

**Female** — Tarsus I usually with one tactile seta completely proximal to and three tactile setae overlapping (i.e. in line or mostly in line with) the proximal pair of duplex setae. Tibia I and tarsus III each with nine tactile setae plus one solenidion. All empodia without dorsal spurs. Pre-genital striae longitudinal with large medial region broken. Dorsal striae forming diamond pattern between setal pairs *e*₁-*f*₁. The body colour during late spring-summer is yellowish green (Figure 11), becoming orangey brown in winter.

**Male** — empodia I with proximoventral hairs fused into single claw, and small dorsal spur (2 long); empodia II to IV without dorsal spur. Aedeagus with a large dorsally directed knob, >2 times diameter of neck; dorsal margin of knob is convex and evenly rounded; knob with a small acute posterior projection (2 long) and a larger rounded anterior projection; anterior margin of anterior projection abruptly recurved into dorsal margin of shaft to produce a distinct narrow neck after which the main shaft abruptly widens (Figures 7–8).

**Description. Adult female (n = 26)**

(Figs. 2–5, 11A–C)

**Body** — Individuals range in color from yellowish green in spring to autumn, to dull orangey brown in winter (Figures 11A, B). Body length from posterior margin of idiosoma to tip of gnathosoma 450–520 (Figure 2A).

**Dorsum** — Propodosomal striae forming U-pattern; striae entirely transverse between *c*₁-*c*₁ and *d*₁-*d*₁; striae form a diamond pattern in the region between the setal pairs *e*₁-*e*₁ and *f*₁-*f*₁ (Figure 2B); with mostly longitudinal striae in region between setal pairs *f*₁ and *f*₂; with irregular striae between setae *f*₂ and *f*₂. Dorsal striae with small rounded lobes (see Figure 2 B). Dorsal idiosoma with a total of 14 pairs of long setae, three pairs of prodorsal setae (*v*₂, *sc*₁, *sc*₂) and 11 pairs of dorsal opisthosomal setae (*c*₁-₂-₃, *d*₁-₂, *e*₁-₂, *f*₁-₂, *h*₂-₃). Lengths of dorsal setae: *v*₂ 65–78, *sc*₁ 125–150, *sc*₂ 87–105, *c*₁ 112–138, *c*₂ 112–125, *c*₃ 92–113, *d*₁ 107–130, *d*₂ 110–125, *e*₁ 105–123, *e*₂ 100–130, *f*₁ 87–110, *f*₂ 75–98, *h*₂ 45–53, *h*₃ 37–45. Distance between setae: *v*₂-*h*₂ 300–360, *v*₂-*v*₂ 57–68, *sc*₁-*sc*₁ 80–88, *sc*₂-*sc*₂ 182–213, *c*₁-*c*₁ 70–90, *c*₂-*c*₂ 142–175, *c*₃-*c*₃ 240–300, *d*₁-*d*₁ 80–100, *d*₂-*d*₂ 195–225, *e*₁-*e*₁ 45–58, *e*₂-*e*₂ 160–180, *f*₁-*f*₁ 45–68, *f*₂-*f*₂ 80–113, *h*₂-*h*₂ 25–35, *h*₃-*h*₃ 77–100.

**Gnathosoma** — Ventral infracapitulum bears subcapitular setae *m* 47–53 long and equal in length to distance between *m*–*m*; setae *or*₁ 5. Dorsal infracapitulum with a pair of peg-like supracoxal setae (*e*); palp four-segmented and setation typical; palp tarsus: with three tactile setae, two eupathidia, one solenidion, and one spinneret; spinneret 1.75 times as long as broad, spinneret length 7, width 4 (Figure 3A). Peritreme strongly hooked distally 20–25 long (Figure 3B).

**Venter** — Area between setal pairs 1a–1a, 3a–3a, and 4a–4a with transverse striations; striae between 1a and 3a without lobes (Figure 2C); lobes present on striae posterior to 3a–3a and laterally on venter in general (Figures 2C, D). Striae between setae *ag*–*ag* transverse with lobes (Figure 4). Pregenital striae longitudinal, with large medial region of broken striae (Figure 4). Genital flap with mostly transverse striae (Figure 4). Anogenital region with one pair of aggenital setae (*ag*), two pairs of genital setae (*g*₁-₂), two pairs of anal setae (*ps*₁-₂). Lengths of ventral setae: 1a 45–58, 3a 50–60, 4a 62–75, *ag* 65–75, *g*₁ 37–48, *g*₂ 37–45, *ps*₁
<figure><img src="image_9.png" /></figure>

**Figure 2** *Tetranychus algarrobus* n. sp. paratype female: A – dorsal habitus; B – pattern of dorsal striae between setal pairs *e*₁-*e*₁ and *f*₁-*f*₁; C – distribution of lobes on the ventral striae between setal pairs 1a–1a and 3a–3a; D – distribution of lobes on the ventral striae between seta 3a–3b and 4a–4b (left side of venter). Scale bar same for **B**, **C**, **D**.
<figure><img src="image_10.png" /><figcaption>**Figure 3** *Tetranychus algarrobus* n. sp. **A** – paratype female palp; **B** – paratype female peritreme; **C** – paratype male peritreme. Scale bar same for **B** and **C**.</figcaption></figure>

17–23, *ps*₂ 17–23. Distances between ventral setae: 1*a*–1*a* 35–43, 3*a*–3*a* 67–78, 4*a*–4*a* 72–85, *ag*–*ag* 62–85, *g*₁–*g*₁ 25–30, *g*₂–*g*₂ 85–103.

**Leg chaetotaxy** — Empodia I–IV without dorsal spurs. Tarsus I usually with one tactile seta completely proximal to and three tactile setae overlapping (i.e. in line or mostly in line with) the proximal pair of duplex setae (Figure 5), rarely with 4 tactile setae completely proximal to proximal duplex setae; distance between the two pairs of duplex setae 20–25. Tarsus II with four tactile setae and one solenidion proximal to duplex setae (distance between duplex seta and proximal solenidion 20–25). Leg setal counts for legs I–IV: cx 2–2–1–1, tr 1–1–1–1, fe 10–6–4–4, ge 5–5–4–4, ti 10(1*ω*)–7–6–7, ta 18(3*ω*)–16(2*ω*)–10(1*ω*)–11(1*ω*).

**Description. Adult male (n = 26)**

(Figs. 1, 3C, 6–9, 11D)

**Body** — Mostly yellowish green in color, with eyes red (Figure 11D). The body length from posterior margin of idiosoma to tip of gnathosoma 300–363.

**Dorsum** — Striae of propodosoma forming U-pattern, striae run transversely for the entire region between setal pairs *c*₁–*c*₁ and *f*₁–*f*₁; striae arching between *f*₂–*f*₂. Lengths of dorsal setae: *v*₂ 42–55 [48], *sc*₁ 80–105 [96], *sc*₂ 52–73 [60], *c*₁ 65–95 [83], *c*₂ 67–88 [80], *c*₃ 62–85 [72], *d*₁ 72–88 [80], *d*₂ 70–100 [84], *e*₁ 57–85 [66], *e*₂ 62–90 [73], *f*₁ 45–68 [50], *f*₂ 37–50 [40], *h*₂ 20–25 [20], *h*₃ 20–25 [20]. Distances between dorsal setae: *v*₂–*h*₂ 190–215, *v*₂–*v*₂ 45–53, *sc*₁–*sc*₁ 57–65, *sc*₂–*sc*₂ 122–133, *c*₁–*c*₁ 52–60, *c*₂–*c*₂ 92–103, *c*₃–*c*₃ 140–163, *d*₁–*d*₁ 55–65, *d*₂–*d*₂ 87–110, *e*₁–*e*₁ 30–38, *e*₂–*e*₂ 72–83, *f*₁–*f*₁ 25–33, *f*₂–*f*₂ 47–53, *h*₁–*h*₁ 17–23, *h*₃–*h*₃ 50–60.
<figure><img src="image_11.png" /><figcaption>**Figure 4** *Tetranychus algarrobus* n. sp. paratype female – pattern of striae in pregenital region.</figcaption></figure>

**Gnathosoma** — Ventral infracapitulum bears subcapitular setae *m* 40–55, subequal in length to distance *m–m* 35–50; setae *or*₁ 5. Dorsal infracapitulum with pair supracoxal setae (*e*); palp four-segmented and setation typical; palp tarsus: with three tactile setae, two eupathidia, one solenidion, and one spinneret. Spinneret length 5, width 2. Peritreme as in female but slightly smaller, 13–17 long (Figure 3C).

**Venter** — Area between setal pairs 1a–1a, 3a–3a, 4a–4a and *ag–ag* with transverse striae; anogenital region with one pair of aggenital setae (*ag*), two pairs of genital setae (*g*₁⁻₂), two pairs of anal setae (*ps*₁⁻₂). Lengths of ventral setae: 1a 37–45, 3a 37–40, 4a 42–50, *ag* 37–50. Distances between ventral setae: 1a–1a 25–30, 3a–3a 45–53, 4a–4a 45–53, *ag–ag* 35–43.

**Leg chaetotaxy** — Empodia I with a small dorsal spur (2 long) (Figure 6), and proximoventral hairs fused into large single claw; empodia II to IV without dorsal spur. Tarsus I with
<figure><img src="image_12.png" /><figcaption>**Figure 5** *Tetranychus algarrobus* n. sp. paratype female (Tarsus I) – distribution of the four tactile setae proximal to the proximal duplex set; note that there is one tactile seta completely proximal (seta numbered 2 above) and three tactile setae overlapping (i.e. in line or mostly in line with) the proximal duplex setae (setae numbered 1, 3, 4).</figcaption></figure>

four pairs of tactile setae and two solenidia proximal to proximal pair of duplex setae; distance between proximal and distal duplex 12–18. Tarsus II with four tactile setae and one solenidion proximal to duplex seta, distance between duplex seta and proximal solenidion 12–18. Leg setal counts as in female except tarsus I: 20(6ω) and tibia I: 13(4ω).

**Aedeagus** — (Figures 1, 7–9) Knob of aedeagus large (4–6 long), two to three times as wide as the neck (2 wide); dorsal margin of knob is convex and evenly rounded; posterior projection of knob acute, short and triangular 2 long; with large rounded anterior projection; anterior margin of anterior projection abruptly recurves into dorsal margin of shaft to produce a distinct narrow neck after which the main shaft abruptly widens; neck below knob 2 wide. Note that dorsal margin of the knob presents as evenly rounded using DIC with no apparent indentation (Figure 7), but under phase contrast the resulting shadows present an illusion that the margin has a minute central indentation (Figure 8). Aedeagus measurements (see Figure 1): a = 6–9 [8], b = 11–15 [12], c = 5–6 [6], d = 34–43 [43]; length of knob 4–6 [4].

**Etymology** — The specific epithet "algarrobus" of the new species is derived from the regional common name of the host tree "algarrobo", a native tree used by local inhabitants for firewood, charcoal production and cattle feed.

**Distribution** — Known only from the type locality in northwestern Peru.

## Remarks

Please note that all species comparisons that follow are based on details taken from the literatures and not from examination of actual specimens or types. *Tetranychus algarrobus* n. sp. shares with *T. amicus* Meyer & Rodrigues, *T. frater* Wainstein, *T. gladioli* Livshits & Mitrofanov, *T. gloveri* Banks, *T. kanzawai* Kishida, *T. merganser* Boudreaux, *T. mkuziensis* Meyer, *T. rooyenae* Meyer, and *T. wainsteini* Baker & Pritchard, an aedeagus with the following character states: a relatively large dorsally-directed knob with a broadly convex dorsal margin, broadly rounded anterior projection and a small acute posterior projection; a narrow neck below the knob; anterior margin of neck strongly recurving to dorsal margin of shaft to produce a distinct and deeply emarginate section (Figure 10).

We note that the various aedeagus illustrations of the above-noted similar species (Figure 10) indicate that the small posterior projection of the knob is directed at slightly to moderately
<figure><img src="image_13.png" /><figcaption>**Figure 6** *Tetranychus algarrobus* n. sp. paratype male – empodium I of the same individual.</figcaption></figure>

different angles in relation to the main axis of the aedeagus shaft. However, these angles, as represented in the illustrations (Figure 10), are likely to be affected by the mounting of the specimen and even the style of the illustrator, and we therefore consider this character difficult to categorise in a consistent and taxonomically significant manner.

**Differential diagnoses**

Of the species listed above, the aedeagus of *T. algarrobus n. sp.* is morphologically most similar to *T. amicus* (Figure 10A) and *T. merganser* (Figure 10G). *Tetranychus algarrobus n. sp.* (*Tal*) can be separated from *T. amicus* (*Tam*) and *T. merganser* (*Tme*) using the following character states of the adult female: *Tal* without spurs on empodia; with the bases of one tactile seta proximal to, and three tactile setae overlapping (i.e. in line or mostly in line with) the proximal duplex setae; pregenital striae broken; yellowy green. *Tam* without spurs on empodia; with the bases of four tactile setae proximal to the proximal duplex setae; pregenital striae longitudinal; dark red. *Tme* with minute spurs on empodia; with the bases of four to five tactile setae proximal to the proximal duplex setae; pregenital striae longitudinal; carmine.
<figure><img src="image_14.png" /><figcaption>**Figure 7** *Tetranychus algarrobus* n. sp., aedeagus of paratype male – four different focal points through the aedeagus of a single individual, using differential interference contrast (DIC).</figcaption></figure>

In addition, *T. algorrobus* n. sp. can be easily morphologically separated from all nine other species of *Tetranychus* recorded from Peru using the following character states: *T. abacae* Baker & Pritchard females and males have a large dorsomedian spur on empodia (*Tal* without spurs, except minute spur on male tarsus I), pregenital region with broken striae in discrete anterior region and longitudinal striae posteriorly (*Tal* with broken striae across full region), aedeagus knob small with acute anterior and posterior projections (*Tal* knob large with convex dorsal margin), recorded as red (*Tal* yellowy green); *T. amazonensis* Guanilo, Flechtmann & Moraes females with minute dorsomedian spur on empodia (*Tal* without spurs), pregenital region with longitudinal striae (*Tal* with broken striae), aedeagus knob with ventrally directed acute anterior and posterior projections (*Tal* knob with large rounded anterior and small acute posterior projections), *T. desterorum* Banks females and males with dorsomedian spur on empodia (*Tal* without spurs, except minute spur on male tarsus I), females with four setae in line with the proximal duplex setae (i.e. no setae proximal) (*Tal* with one seta proximal,

<figure><img src="image_15.png" /><figcaption>**Figure 8** *Tetranychus algarrobus* n. sp., aedeagus of paratype male – three different focal points through the aedeagus of a single individual, using phase contrast (images by P. Auger).</figcaption></figure>
<figure><img src="image_16.png" /><figcaption>**Figure 9** *Tetranychus algarrobus* n. sp. paratype males: **A** – aedeagus at three different focal points; **B** – aedeagus of second paratype male.</figcaption></figure>

and three setae in line), pregenital striae longitudinal (*Tal* broken), aedeagus with small acute anterior projection and large ventrally directly spur-like posterior projection (*Tal* with large rounded anterior and small acute posterior projections), recorded as red (*Tal* yellowy green); *T. ludeni* Zacher similar to *desertorum* except females with empodial spur minute or absent and with broken striae, and aedeagus without posterior projection; *T. mexicanus* (McGregor) females and males with large dorsomedial spur on empodia (*Tal* without spurs, except minute spur on male tarsus I), females with four tactile setae proximal to proximal duplex setae (*Tal* with one proximal seta), females with two proximal tactile setae on tarsus III (*Tal* with one seta proximal), aedeagus knob with small acute anterior projection and large acute posterior projection (*Tal* knob with large rounded anterior and small acute posterior projections); *T. neocaledonicus* André females with four setae proximal to proximal duplex setae (*Tal* with one seta proximal), aedeagus with small knob with small rounded anterior and posterior projections (*Tal* knob with large rounded anterior and small acute posterior projections); *T. singularis* Guanilo, Flechtmann & Moraes females and males with small dorsomedial spur on empodia, pregenital striae longitudinal with a small region of broken striae medially (*Tal* with broken striae), aedeagus knob with more or less truncate dorsal margin with small acute anterior and large acute posterior projections (*Tal* knob with convex dorsal margin), recorded as red (*Tal* yellowy green), *T. urticae* Koch females with four setae proximal to proximal duplex setae (*Tal* with one seta proximal), pregenital striae longitudinal and often sparse (*Tal* with broken striae), aedeagus knob small with angulate dorsal margin (*Tal* knob large with convex dorsal margin), *T. zamithi* Paschoal females with minute dorsomedial spur on empodia, females with four tactile setae proximal to proximal duplex seta (*Tal* with one seta proximal), aedeagus knob small with small rounded anterior and posterior projections (*Tal* knob large with large rounded anterior and small acute posterior projections).

Although the living colour of spider mites is not always noted, it can be an important
<figure><img src="image_17.png" /></figure>

**Figure 10** The aedeagi of species morphologically similar to *Tetranychus algarrobus n. sp.* A *T. amicus* (reproduced from Meyer & Rodrigues, 1966); B *T. frater* (reproduced from Wainstein, 1960); C *T. gladioli* (reproduced from Livshits & Mitrofanov, 1980); D *T. kanzawai* (reproduced from Pritchard & Baker, 1955); E *T. rooyenae* (reproduced from Meyer, 1974); F *T. gloveri* (reproduced from Sharkey *et al.*, 2022); G *T. merganser* (reproduced from Boudreaux, 1954); H *T. mkuziensis* (reproduced from Meyer, 1974); I *T. wainsteini* (reproduced from Baker & Pritchard, 1962); J *T. algarrobus n. sp.* (Holotype). Note – scale bars are often not provided in early descriptions, and hence are not provided here.

character for separating species; however, colour must be used with caution as it often changes with seasons. Thus, in the comparisons that follow, the collection month is also noted. All the similar species compared above are recorded as being red, except *T. frater* and *T. gladioli*, which are recorded as green: *T. amicus* dark red, collected in January, March, November in South Africa (summer to autumn); *T. frater* green in summer, collected in North Kazakhstan Region; *T. gladioli* green in summer, collected in August Crimea (summer); *T. gloveri* red, collected in September USA (autumn); *T. algarrobus n. sp.* yellowy green, May (autumn), orangey brown, August (winter); *T. kanzawai* carmine red, March, September, October Japan (spring, autumn); *T. merganser* carmine to dark reddish-purple, collected in July USA (summer); *T. mkuziensis* dark red, January South Africa (summer); *T. rooyenae* dark red, collected in September South Africa (spring); *T. wainsteini* red, March Central America (spring).

## Ecological observations

The new species inhabits the abaxial (lower) surface of the leaf of its host tree, algarrobo *N. piurensis* (Figure 11A). During the study, the minimum temperature ranged between 16.0 to 23.0 °C, maximum temperature ranged between 26.1 to 34.7 °C, and relative humidity averaged 73.5%. This species forms colonies and produces abundant webbing (Figure 11B). High mite populations produce sufficient webbing to cause the leaves and branches to become matted together, and severe damage caused leaf drop and even the death of the affected branches (observed frequently and abundantly in winter). In winter, a population density of 21 mites/leaf was found, with mites occupying about 90% of all leaves evaluated. The eggs are often laid on the abaxial surface of leaves, are spherical in shape, and clear in color but become ivory before hatching. Larvae and nymphs are pale straw-coloured with two large black spots on each side of the idiosoma, from the eyes to mid-dorsum (Figure 11C). Females are yellowish green in spring, summer, and autumn, but become orangey brown in winter, with black regions on the dorsolateral propodosoma and hysterosoma, the eyes are red. Males are yellowish green in color with red eyes (Figure 11D).
<figure><img src="image_18.png" /><figcaption>**Figure 11** Live females and males of *Tetranychus algarrobus* n. sp. **A** – female with characteristic yellowy green color (collected in February, summer in Peru); **B** – female with characteristic color in winter (collected in August, winter in Peru); **C** – female, eggs, and immature stages on underside of leaf of *Neltuma piurensis*; **D** – male with an egg.</figcaption></figure>

**Acknowledgments**

We want to express our thanks to Prof. Carlos H. W. Flechtmann (Brazil) for the information and literature for this study. We also thank to express our special thanks go to Gregory Evans (APHIS-USDA), Andrew Ulsamer (ARS-USDA), and Cal Welbourn (NMNH) for the revision and suggestions to the manuscript. To the Smithsonian Natural History Museum (NMNH) and National Agricultural Library (NAL-USDA), SEL-USDA for support and assistance with specimens and references. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. USDA is an equal opportunity provider and employer.
ORCID

Hector Alonso Escobar-García ID https://orcid.org/0000-0002-5003-2268

Daniel Júnior de Andrade ID https://orcid.org/0000-0003-0054-879X

Jennifer J. Beard ID https://orcid.org/0000-0003-0734-1011

Ronald Ochoa ID https://orcid.org/0000-0003-1680-3601

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