Research Article

A New Species of the Genus Pseudostigmaeus Wood (Acari: Prostigmata: Stigmaeidae) from Pakistan

Bilal Saeed Khan1*, Muhammad Afzal2, Muhammad Asif Qayyoum1, Imran Ali3 and Abdul Ghaffar3

1Department of Entomology, University of Agriculture, Faisalabad, Pakistan; 2Professor and Dean, College of Agriculture, University of Sargodha, Sargodha, Pakistan; 3Ayub Agricultural Research Institute, Faisalabad, Pakistan.

Received | November 24, 2019; Accepted | January 30, 2020; Published | June 15, 2020

*Correspondence | Bilal Saeed Khan, Department of Entomology, University of Agriculture, Faisalabad, Pakistan; Email: [email protected]; [email protected]

Citation | Khan, B.S., M. Afzal, M.A. Qayyoum, I. Ali and A. Ghaffar. 2020. A new species of the genus Pseudostigmaeus wood (Acari: Prostigmata: Stigmaeidae) from Pakistan. Pakistan Journal of Agricultural Research, 33(2): 311-315.

DOI | http://dx.doi.org/10.17582/journal.pjar/2020/33.2.311.315

Keywords | Stigmaeidae, Pseudostigmaeus, Acari, New species, Predatory mite

Introduction

Stigmaeidae is considered as major family within Raphignathoidea and comprise a large cosmopolitan of near about 500 species grouped into 32 valid genera (Dogaan et al., 2011; Khanjaani et al., 2012a) including the genus Ueckermann in 2008. Stigmaeid mites naturally minute, often red to yellow orange arachnids, that occur in many habitat and giving an important slice of the soil texture, leaf litter and aerial plant parts. Stigmaeids are proved to be a large cluster of predators that feed on variety of arthropod pest, ectoparasites of flies and also pollen feeders (Summers, 1966; Meyer and Ueckerman, 1987; Walter et al., 2009). Stigmaeid mites are considered as efficient feeders against the tetranychid, tenuipalpid and eriophyid mites (Santos and Laing, 1985). Stigmaeid mites are well known predators against the phytophagous mites, soft small insect bodies and feeding on a variety of arthropods (Swift, 1987; Akyol and Kocc, 2007; Khanjani et al., 2010). The total eight species of genus Pseudostigmaeus were introduced from world (Pseudostigmaeus wood as type specimen) including one from Pakistan i.e., Pseudostigmaeus jhangensis. All specimens were deposited in the Acarology Research Laboratory, Department of Entomology, University of Agriculture, Faisalabad, Pakistan.

Diagnosis

Wood (1967) created the genus Pseudostigmaeus, distinguishing it by the presence of 3 pairs of setae on median propodosomal plate, the presence of inter coxal plates and 1-2 setae on coxa II. Body soft and weakly reticulated, chelicerae separated, Palptibia with 2 simple setae, main claw sometimes with 1 accessory claw, palptarsus bearing 4 setae, 1 soledion, 1 spine and 1 trifid eupathidium. Dorsal setae 11-13 pairs (sometimes vi absent as in this new species). Dorsum covered by 1 propodosomal shield and 1 pair of small suranal shield. Propodosoma 1 pair of eyes. Mostly genital area provided with a single genital pore, 3 pairs of anogenital setae and 3 pairs of paraproctal setae. Mites of this genus often collected from living plants or soil leaf litter. The mites of this genus were recorded from New Zealand, China, Ireland, South Africa and Pakistan, respectively. A new species has been collected by the author from Punjab, Pakistan and described here in this manuscript which is compared with Pseudostigmaeus capensis Meyer and P. ueckermanni Ueckermann for differences.

Materials and Methods

Mite of the genus Pseudistigmaeus (Acari: Prostigmata: Stigmaeidae) were collected by (Bilal Saeed Khan) from Sorghum bicolor (L.) through sieve collection method. The slides were equipped by using the solution of Hoyer’s and drawn with the help of eye piece /microscope. The species have been identified with the help of the accessible keys and text. Grandjean’s system of terminology (Grandjean, 1944) with modifications/additions made by (Summers, 1960; Gonzalez, 1965) were used. All measurements are in micrometers (µm). The abbreviations used in this manuscript as:

ve (be): pre-ocular dorsal setae; sci (ce): post ocular dorsal setae; c1 (a): dorsocentral dorsal setae (l); d1 (b): dorsocentral dorsal setae (lI); e1 (c): mediozonal setae; h1 (e): central suranal setae; c2 (he): humeral setae; d2 (la): dorsolateral dorsal setae; f1 (Ii): intercalary dorsal setae; e2 (Im): lateral zonal setae; ag1, ag2, ag3: agenital setae; ps1, ps2, ps3: paraproctal setae; he: humeral seta (ventrally visible); vi (ae): vertical dorsal setae (absent in this new species). Notes: i. Kethley (1990) has given dorsal setal nomenclature and shield designations respectively. ii. Oldsetal abbreviations are given in brackets.

Results and Discussion

Wood 1967 erected the genus Pseudostigmaeus based on type species as P. collyerae Wood and P. striatus Wood at the same time. Meyer and Ryke (1969) described P. capensis Meyer from South Africa and redefined the genus with a new diagnosis. But later, P. capensis removed and designated as the genotype of a new genus Parastigmaeus Kuznetsov (Kuznetsov and Petrov, 1984). Wood (1970) described 1 species (Pseudostigmaeus longisetis) Campell Island from moss. Later Wood provided a key to species from New Zealand in 1971. Momen (1987) described Pseudostigmaeus arboricolus from apple tree in Ireland. A new species P. ueckermanni (1987) was collected from China.

Description of Pseudostigmaeus sorghumus sp. nov

Female: (Dorsum) Body long slender pear shape 435 µm (without gnathosoma), 230 µm wide, chelicerae length 92 µm, stylets 42 µm long. Palptarsus slightely longer than main claw. palptarsus well developed and reaches past the tibial claw. The setae disposed on the palpal segment provided femur 2, genu 2, tibia 2, tarsus with 4 minute setae and provided with trifid sensillum. Base of the chelicerae are not fused together. Peritreme obvious having the length of 73 µm, eyes 1 pair large in size (Figure 1). Post-ocular body absent. Propodosomal shield having rounded corners. The 1st pair of propodosomal seta ve is not located on anterior margin of propodosomal plate. The 2nd pair of propodosomal seta sci situated immediately in front of eyes. The 3rd pair of propodosomal seta sce shorter in length than the seta sci and not present on the propodosomal plate. Humeral seta he absent dorsally. Metapodal shield completely invisible and whole area covered with straight and vertical striations. Dorsal idiosomal setae provided with tiny platelets except f1; seta f1 present. 5 pairs of setae on hysterosoma shorter in length than the setae h1 and h2. The respective distances between ve-ve 33, sci-sci 68, sce-sce 145, c1-c1 85, d1-d1 93, e1-e1 50, f1-f1 85, c1-d1 82, d1-e1 60, e1-f1 37, d2-d2 180, e2-e2 155. The length of dorsal setae ve 17, sci 23, sce 15, he 17; seta h1 16, d1 15, e1 15, d2 15, e2 13, f1 18, h2 20, h1 28 and f118.

Venter: Ventral gnathosoma provided 3 pairs of setae, 3rd pair of seta longest. In 5 pairs of idiosomal setae, 1st pair much longer than others and this 1st pair present between coxae I and II. Humeral seta he present ventrally. 3 pairs of anogenital setae (ag1, ag2, ag3) smooth while regarding paraproctal setae, the 2nd and 3rd one is barbed except Ist pair (Figure 2).

Legs: Chaetotaxy of legs I-IV as (Figure 3): coxae 2-1-1-1; trochanters 0-0-1-1; femora 4-4-2-2; genua 3-1-0-0; tibiae 3-4-3-4 and tarsi 10-6-5-5.

1. 1. Tridentate spine absent on tarsalpeg; palptibia with 1 seta; palp tarsalpeg equal with main claw; dotted striations on propodosomal shield; 11-pairs dorsal setae..…. jhangensis
2. 2. Tridentate spine present; palptibia with more than 1 seta; palp tarsalpeg longer than main claw; propodosomal shield without dotted striations; 12-13 pairs dorsal setae…… 2
3. 3. Propodosomal shield incompletely visible; metapodal shield visible; ventral idiosoma partially striated; anogenital setae serrate……solanumus (n.sp) (Figures 1 and 2)
4. 4. Propodosomal shield completely visible; metapodal shield not visible; ventral idiosoma completely striated; anogenital setae not serrate………3
5. 5. Dorsal setae smooth; humeral seta ventrally present; anogenital plate not rounded in shape; smooth paragenital setae; barbed anogenital setae; 3 setae on tibia-I ..……sorghumus sp.nov.
6. 6. Dorsal setae not smooth; humeral seta ventrally absent; anogenital plate rounded in shape; paragenital setae not smooth; anogenital setae not barbed; more than 3 setae on tibia-I…….4
7. 7. Palpgenu with 2 setae; postocular body absent; seta f1 present; 4 pairs of anogenital setae; ventral idiosoma provided with 5 setae…...ueckermanni Fan and Liu
8. 8. Palpgenu without setae; postocular body present; seta f1 absent; 3 pairs of anogenital setae; ventral idiosoma provided with 6 setae………capensis (Meyer)

Acknowledgement

Authors acknowledge Higher Education Commission of Pakistan for financial support to conduct this research work. We are thankful to Dr. Eddi Ueckerman from South Africa for literature help and also grateful for the guidance of Prof. Dr. Shamshad Akbar (Late) regarding preparation of manuscript. This paper is also presented by author # 1 during European Congress of Entomology Napoli, Italy 2018.

Author’s Contribution

Bilal Saeed Khan: Principal and Corresponding author. Wrote the abstract and introduction. Did methodology of work ad data collection.

Muhammad Afzal: P.I of whole research work project. Plan the idea of research work.

Muhamma Asif Qayyoum: Development of key formation and character data entry. Technical inputs.

Imran Ali: Write up of key characters and analysis and improve discussions.

Abdul Ghaffar: Revised study if genus and literature help with results/conclusion.

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