Pentamerismus (Oligomerismus) retusus Meyer, 1979

Mirza, Jawwad Hassan, Elgoni, Nasreldeen Ahmed, Kamran, Muhammad & Alatawi, Fahad Jaber, 2025, Subgenera of the genus Pentamerismus McGregor (Acari: Tenuipalpidae) with the re-description of Pentamerismus retusus Meyer and a key to species of the world, Zootaxa 5601 (1), pp. 143-156 : 146-153

publication ID	https://doi.org/10.11646/zootaxa.5601.1.7
publication LSID	lsid:zoobank.org:pub:7DB0F83E-857F-4501-9172-93C70326A650
DOI	https://doi.org/10.5281/zenodo.14980684
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scientific name	Pentamerismus (Oligomerismus) retusus Meyer, 1979
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Treatment

Pentamerismus (Oligomerismus) retusus Meyer, 1979 View in CoL

Pentamerismus retusus Meyer, 1979: 130 View in CoL , figs. 460–463; Meyer & Van Dis 1993: 323, figs. 57–58; Alatawi et al. 2015: 827.

Material examined. Six females (KSMAAS14-Ten-Pen-01–06) and three males (KSMAAS14-Ten-Pen-07–09), ex Zygophyllum simplex Linnaeus ( Zygophyllaceae ), Saudi Arabia, Riyadh province, King Saud University, near College of Food and Agriculture Science, 24°50’57’’ N, 46°33’149’’ E, 30 April 2014, coll. M. Kamran.

Complementary description of female (n=6)

Dorsum ( Figure 1 View FIGURE 1 ). Idiosoma oval in shape, length of body (excluding gnathosoma) 225 (212–237); (including gnathosoma) 275 (263–287) long; 127 (119–113) wide.

Anterior margin of dorsal propodosoma rounded with no anterior notch; dorsal propodosomal setae (v 2, sc 1, sc 2) subspatulate serrate; length of seta v 2 half as long as distance between setae v 2 –v 2; dorsal propodosoma with weak longitudinal striation medially; posterior opisthosoma entirely with longitudinal striations; transverse striation in line of setae d 1; medial striation between the setae c 1 and d 1 dome shape pattern, slightly irregular dorsolaterally; opisthosoma with three pairs of dorsocentral setae (c 1, d 1, e 1), two pairs of dorsolateral setae (c 2, d 2), seven pairs of dorsolateral setae (c 3, d 3, e 2, e 3, f 3, h 1, h 2); first row of dorsal opisthosomal setae c 1, c 2, c 3 subspatulate; other central and lateral dorsal opisthosomal setae broadly spatulate, becoming broader toward posterior; setae f 2 absent. Lengths of dorsal setae as follows: v 2 14–17, sc 1 18–22, sc 2 19–24, c 1 18–22, c 2 15–19, c 3 14–17, d 1 16–22, d 2 15–19, d 3 14–17, e 1 13 –18, e 2 13 –16, e 3 14 –19, f 3 10–14, h 2 10–14, h 1 10–15. Distances between dorsal setae: v 2 –v 2 33–39, v 2 –sc 1 25–30, sc 1 –sc 2 23–28, sc 1 –sc 1 63–72, sc 2 –sc 2 91–99, c 1 –c 1 41–47, c 1 –c 2 25–30, c 2 –c 3 11–15, c 2 –c 2 89–97, c 3 –c 3 118–129, c 1 –d 1 31–37, c 2 –d 2 33–43, c 3 –d 3 42–50, d 1 –d 1 35–40, d 1 –d 2 20–24, d 2 –d 3 13–15, d 2 –d 2 100–112, d 3 –d 3 105–114, d 1 – e 1 40–47, d 3 – e 3 18–22, e 1 – e 1 20–25, e 1 – e 2 35–42, e 2 – e 3 20–23, e 2 –e 2 105–113, e 3 –e 3 90–99, e 3 –f 3 20–25, f 3 –f 3 67–74, f 3 –h 2 19–24, h 1 –h 1 15–19, h 1 –h 2 15–20, h 2 –h 2 45–51, e 1 –h 1 42–49.

Venter ( Figure 2 View FIGURE 2 ). Ventral propodosoma with transverse striation; longitudinal striations between setae 3 a and 4 a, transverse striations posterior to 4 a and anterior to setae ag, immediately posterior to coxae IV with transverse striae laterally; oblique to transverse striae anterolateral to genital shield. Length of setae: 1 a 90–112, 1 b 19–26, 1 c 15–20, 2 b 16–20, 2 c 20–26, 3 a 15–22, 3 b 13–17, 4 a 15–20, 4 b 14–19, ag 17–22, g 1 14–19, g 2 16–20, ps 3 7–10, ps 2 9–13, ps 1 11–14. Ventral setae 1 a whip-like, three to four times longer than 3 a. Genital and anal shields coarsely striated ( Figure 2A View FIGURE 2 ); aggenital setae (ag) serrated, equal in length to genital setae (g 1 – 2) also serrated; anal shields with three pairs of setae (ps 1–3), ps 1 –2 narrowly lanceolate. Distances between ventral setae: 1 a– 1 a 20–27, 3 a– 3 a 36–40, 4 a –4 a 26–33, 1 b –1 c 11–15, 2 b –2 c 20–22, 1 a –3 a 51–59, 3 a– 4 a 30–38, 4 a–ag 56–63, ag–ag 13–15, g 1 –g 1 15–20, g 2 –g 2 35–41, g 1 –g 2 10–13, ag–g 1 22–27, ag–g 2 21–28, g 1 –ps 1 32–38, g 1 –ps 2 30–37, g 1 –ps 3 8–32, g 2 – ps 1 37–44, g 2 –ps 2 30–34, g 2 –ps 3 27–32. Spermatheca globular elongate ( Figure 2B View FIGURE 2 ).

Gnathosoma ( Figure 3 View FIGURE 3 ). Subcapitulum with one pair of setae m ( Figure 3A View FIGURE 3 ) Rostrum reaching to the distal end of genu I; palp five segmented, palp tarsus with one solenidion and two eupathidia distally, where inner eupathidion is distinctly smaller; palp tibia with two setae, palp femur and genu without setae ( Figure 3B View FIGURE 3 ).

Legs ( Figure 4 View FIGURE 4 ). Legs are short, less than one third the length of idiosoma; Length of leg I 78–85; leg II 66–71; leg III 70– 75; leg IV 71–78. Setal formulae of leg segments as follows: coxae 2-2-1-1; trochanters 1-1-2-1; femora 4-4-2-1; genua 2-2-0-0; tibiae 4-4-3-3; tarsi 8(1 ω)-8(1 ω)-5-5. Dorsal setae on femur I–III, genu I-II and tibiae I narrowly lanceolate and distinctly serrated ( Figure 4 View FIGURE 4 ). Tarsus I and II each with one antiaxial solenidion (ω) 10–12 and 8–10 long, respectively ( Figure 4 View FIGURE 4 ). Tarsal claws uncinate and empodia pad-like.

Description of male (n=3)

Dorsum ( Figure 5 View FIGURE 5 ). Idiosoma oval in shape, length of body (excluding gnathosoma) 144–149; (including gnathosoma) 197–200 long; width 83–88 wide. Anterior margin of dorsal propodosoma rounded with no anterior notch; dorsal propodosomal setae (v 2, sc 1, sc 2) subspatulate serrate; length of seta v 2 more than half the distance between setae v 2 –v 2; dorsal propodosoma with circular longitudinal striae becoming weak medially as in female; dorsal opisthosomal setae c 1–3 subspatulate; other dorsal opisthosomal setae broadly spatulate, becoming broader toward posterior; setae f 2 absent. Lengths of dorsal setae as follows: v 2 16 – 18, sc 1 15 – 18, sc 2 16 – 17, c 1 11 – 15, c 2 10 – 13, c 3 8 – 10, d 1 10–11, d 2 8–11, d 3 9–13, e 1 8 –13, e 2 10 –13, e 3 8 –10, f 3 10–11, h 2 10–12, h 1 9–11. Distances between dorsal setae: v 2 –v 2 23 – 25, v 2 –sc 1 16 – 18, sc 1 –sc 2 16 – 18, sc 1 –sc 1 46 – 49, sc 2 –sc 2 52–55, c 1 –c 1 26–29, c 1 –c 2 16 – 21, c 2 –c 3 8 – 9, c 2 –c 2 53 – 54, c 3 –c 3 71–75, c 1 –d 1 18–22, c 2 –d 2 21–23, c 3 –d 3 27–32, d 1 –d 1 24–25, d 1 –d 2 11–12, d 2 –d 3 8–10, d 2 –d 2 47–49, d 3 –d 3 65–66, d 1 – e 1 16–19, d 3 – e 3 34–35, e 1 – e 1 16–21, e 1 – e 2 15–16, e 2 – e 3 15–16, e 2 – e 2 48 – 50, e 3 – e 3 44 – 49, e 3 –f 3 8–10, f 3 –f 3 32 – 36, f 3 –h 2 11–12, h 1 –h 1 5–7, h 1 –h 2 7–8, h 2 –h 2 23–25, e 1 –h 1 29–31.

Venter ( Figure 6 View FIGURE 6 ). Ventral propodosoma and inter-coxal area between setae 1a and 3a with transverse striation; area between coxae III–IV with longitudinal striae, area posterior setae 4a with transverse striae. Length of setae: 1 a 42–49, 1 b 28–29, 1 c 22–25, 2 b 19–20, 2 c 18–21, 3 a 15–18, 3 b 13–17, 4 a 15–17, 4 b 13–15, ag 13–17, g 1 10–11, g 2 9–10, ps 3 10–11, ps 2 10–12, ps 1 9–11. Ventral setae 1a whip-like, three times longer than 3 a; aggenital setae (ag); genital setae serrated (g 1 – 2); anal shields with 3 pairs of serrated setae (ps 1 – 3). Distances between ventral setae: 1 a– 1 a 13–16, 3 a– 3 a 23–28, 4 a –4 a 16–18, 1 b –1 c 8–10, 2 b –2 c 15–17, 1 a –3 a 43–46, 3 a– 4 a 20–22, 4 a–ag 54–56, ag–ag 11–13, g 1 –g 1 6–7, g 2 –g 2 14–16, g 1 –g 2 4–5, ag–g 1 24–26, ag–g 2 28 – 33 ( Figure 6A View FIGURE 6 ). Aedeagus ( Figure 6C View FIGURE 6 ) long, pointed at tip.

Gnathosoma ( Figure 6B View FIGURE 6 ). Rostrum reaching to the distal end of genu I; palp ( Figure 6B View FIGURE 6 ) 5 segmented, palp tarsus with one solenidion and two eupathidia distally; palp tibia with two setae, palp femur and genu without setae.

Legs ( Figure 7 View FIGURE 7 ). Legs are short, less than half length of idiosoma; Length of legs measured from (trochanter to tarsus), leg I 66–67; leg II 61–62; leg III 59–60; leg IV 64–66. Setal formulae of leg segments as follows: coxae 2-2-1-1; trochanters 1-1-2-1; femora 4-4-2-1; genua 2-2-0-0; tibiae 4-4-3-3; tarsi 8(1 ω)-8(1 ω)-5-5. Tarsus I and II each with one antiaxial solenidion (ω”) 8 (7-8), 7 (6–7) long. Tarsal claws uncinate and empodia pad-like.

Remarks. The Saudi specimen of Pentamerismus (Oligomerismus) retusus morphologically resembles the original ( Meyer 1979; South Africa) and supplementary descriptions ( Meyer 1993; Namibia). The Saudi specimens were compared with the images of the holotype of P. (O.) retusus . The dorsomedial striae on propodosoma are longitudinal and weak in Saudi specimens (female and male), while in compared specimens, striae form a circular pattern ( Meyer 1979, holotype) or surface is rugose ( Meyer 1993). The pattern of striation between setal rows C and D in our specimens is mostly transverse with a small region of arched striae compared to irregular to transverse striaein the holotype ( Meyer 1979). The propodosomal setae of Saudi specimen (female and male) are subspatulate serrate in shape compared to broadly spatulate ( Meyer 1979) and broadly lanceolate to subspatulate ( Meyer 1993). The length of dorsal propodosomal setae v 2 is half the distance v 2 –v 2 compared to one third in the holotype ( Meyer 1979, 1993).