Petrobia (Petrobia) arabica Mirza & Kamran & Alatawi 2023, sp. nov.
Creators: name: Mirza, Jawwad Hassan
name: Kamran, Muhammad
name: Alatawi, Fahad Jaber
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Tetranychidae
Petrobia
Petrobia arabica

description: Petrobia (Petrobia) arabica sp. nov.
Diagnosis. Females with palp tibial claw bifid, femur I–II with six setae each, tibiae III–IV with five setae each, stylophore anteriorly indented, setae f 1 shorter than the distance f 1 –f 2, setae f 1 –f 2 and h 1 appear on tiny bulges.
Description
Female (n = 6): Length of body (v 2 –h 1) 495 (490‒497), including gnathosoma 602 (585‒ 604); width (c 3 –c 3) 382 (378‒385); length of legs (from trochanter to distal end of tarsus): leg I 332 (330‒332); leg II 238 (237‒238); leg III 252 (250‒251), leg IV 302 (299‒332); leg I/ v2–h1: 0.67.
Dorsum. (Figure 1) Propodosomal shield defined by weak longitudinal irregular striations, two pairs of eyes; lateral idiosoma with longitudinal striations, opisthosomal striae fine, transverse medially between setae c 1 –h 1, except submedially changing to v-shaped striation pattern posterior to setae d 1 and e 2 (Figure 1). Dorsal setae lanceolate, slender serrate, shorter than the longitudinal distance between the setae next in line; setae f 1, f 2 and h 1 appear to be present on very tiny bulges or tubercles. Lengths of dorsal setae v 2 36(35‒37), sc 1 33 (33‒35), sc 2 34 (32‒37), c 1 34 (32‒35), c 2 32 (30‒35), c 3 33 (30‒34), d 1 31 (29‒33), d 2 33 (31‒37), e 1 33 (32‒38), e 2 29 (27‒31), f 1 31 (30‒36), f 2 33 (31‒39), h 1 34 (32‒39). Distances between dorsal setae v 2 –v 2 62 (62‒65), sc 1 –sc 1 162 (160‒166), sc 2 –sc 2 240 (238‒241), c 1 –c 1 100 (102‒105), d 1 –d 1 61 (59–63), e 1 –e 1 62 (58–64), f 1 –f 1 51 (49‒51), h 1 –h 1 38(35–38), c 1 –d 1 80 (78‒84), d 1 –e 1 74 (72‒79), e 1 –f 1 75 (71‒77), f 1 –h 1 95 (91‒98).
Venter. (Figures 2, 3) Area between setae 1a–3a with transverse striae, 3a–4a with longitudinal striae, posterior opisthosoma with transverse striae, anterior of genitoanal area with longitudinal striae (Figure 2). Lengths of setae: la 41 (40‒44), 1b 46 (45–48), 1c 26 (24‒29), 2b 31(29‒32), 2c 25 (22‒28), 3a 38 (33‒39), 3b 25 (24‒29), 4a 44 (42‒48), 4b 29 (26‒33), one pair of aggenital setae (ag), two pairs of genital setae (g 1 ‒g 2) and three pairs of anal setae (ps 1‒3) (Figure 2). Spermatheca with very elongated sacculus 15 (13– 15) (Figure 3).
Gnathosoma. (Figures 4, 5) Ventral infracapitulum with one pair of adoral setae or 3 (2‒5) and one pair of subcapitular setae m 39 (36‒42). Palp five-segmented, palp tarsus with one solenidion, three eupathidia and three simple setae; palp tibia with three setae and one bifid claw distally, palp genu and palp femur each with one serrated seta (Figure 4). Stylophore anteriorly indented, peritremes with small anastomosed ends (Figure 5a,b).
Legs. (Figures 6–10) Leg I shorter than body length. Leg segment setal formula as follows: coxae 2-2-1-1; trochanters 1-1-1-1; femora 6-6-3-3; genua 4-4-3-3; tibiae 9(1φ)-5-5-5; tarsi 11 (1 ω) (2dup)-9 (1dup)-9 (1dup)-9 (1dup). Tarsus I and IV with solenidia Iω ′ 49 (49‒50), Iω ″ 57 (56‒58), IIω ″ 40 (40‒42), IIIω ′ 51 (50‒53), IVω ′ 52 (52‒54) and tibia I with Iφ 1 26 (25‒26). Most leg setae narrowly lanceolate, barbed; setae at tips of tarsi slender,smooth. Empodia I–IV with true claws pad-like, two-thirds the length of empodial claws bearing two rows of ventrally directed hairs (Figure 10).
Etymology. The specific epithet is derived from the region where the new species was collected (arabica = Saudi Arabia).
Type materials. One holotype and five paratype females, Haloxylon salicornicum (Amaranthaceae), Domat ul Jandal, Jouf, 29.81547°N, 39.71381°E, 14 April 2022, coll. N. Elgoni.
Remarks
The new species belongs to the subgenus Petrobia (Petrobia) because of its anastomosing peritremes. This subgenus comprises 16 species and the new species is morphologically closer to P. (P.) jingheensis Ma and Gao (China) and P. (P.) pseudotetranychina Auger and Flechtmann (Tunisia) based on the following combination of characters: femur III–IV and genu III–IV each with three setae, dorsal setae short, spatulate to lanceolate and shorter than longitudinal intervals between them, dorsal striation smooth; striae between setae c1–d1 transverse, setae f1 and f2 1– 2 times longer than the other opisthosomal setae. However, the new species is distinct in terms of the number of setae on leg femur I–II (6–6 vs 8– 5 in both P. (P.) jingheensis and P. (P.) pseudotetranychina), and on leg tibiae III–IV (5–5 vs 7– 7 in P. (P.) jingheensis and 8– 8 in P. (P.) pseudotetranychina), stylophore deeply indented vs rounded and in palp tibial claw bifid vs one intact claw in P. (P.) jingheensis and P. (P.) pseudotetranychina. Futhermore, the new species has leg I shorter than body vs as long as body, setae f 1 shorter than f 1 -f 2 vs longer in P. (P.) pseudotetranychina.
description: Published as part of Mirza, Jawwad Hassan, Kamran, Muhammad & Alatawi, Fahad Jaber, 2023, Two new species of the subgenus Petrobia (Petrobia) Müller from Saudi Arabia, pp. 1178-1191 in Journal of Natural History 57 (21 - 24) on pages 1179-1185, DOI: 10.1080/00222933.2023.2238947, http://zenodo.org/record/8270909