Petrobia (Petrobia) arabica, Mirza & Kamran & Alatawi, 2023

Mirza, Jawwad Hassan, Kamran, Muhammad & Alatawi, Fahad Jaber, 2023, Two new species of the subgenus Petrobia (Petrobia) Müller from Saudi Arabia, Journal of Natural History 57 (21 - 24), pp. 1178-1191 : 1179-1185

publication ID	https://doi.org/ 10.1080/00222933.2023.2238947
DOI	https://doi.org/10.5281/zenodo.8268413
persistent identifier	https://treatment.plazi.org/id/03AE8275-FFC0-FF9E-FE76-FA0F323E6AA4
treatment provided by	Plazi
scientific name	Petrobia (Petrobia) arabica
status	sp. nov.

Treatment

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 View 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 View 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 View Figure 2 , 3 View Figure 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 View 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 View Figure 2 ). Spermatheca with very elongated sacculus 15 (13– 15) ( Figure 3 View Figure 3 ).

Gnathosoma. ( Figures 4 View Figure 4 , 5 View Figure 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 View Figure 4 ). Stylophore anteriorly indented, peritremes with small anastomosed ends ( Figure 5a,b View Figure 5 ).

Legs. ( Figures 6–10 View 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 View Figures 6–10 ).

Etymology. The specific epithet is derived from the region where the new species was collected ( arabica = Saudi Arabia).

Type materials. One holotype and GoogleMaps five paratype females, Haloxylon salicornicum (Amaranthaceae) , Domat ul Jandal, Jouf , 29.81547°N, 39.71381°E, 14 April 2022, coll. N. Elgoni. GoogleMaps

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.