Arabapolonia omanensis, Stekolnikov, Alexandr A., Carranza, Salvador & Gomez-Diaz, Elena, 2012

Stekolnikov, Alexandr A., Carranza, Salvador & Gomez-Diaz, Elena, 2012, A new genus and species of Apoloniinae (Acari: Trombiculidae) from Oman, Zootaxa 3499, pp. 74-80 : 76-79

Arabapolonia omanensis sp. nov.

(Figs. 1, 2)

Diagnosis. SIF = 6BS-N(b)-1-2110.0000; fsp = 7.7.7; fCx = 1.0.1; fSt = 0.2.4; fPp = B/B/BBB; fSc: PL> AM> AL; Ip = 711–941; fD = 2H- 10-8-8 (7)-6-4(2); DS = 35–38; VS = 15–17; NDV = 52–53. Standard measurements given in Table 1.

Slide AW PW SB ASB PSB SD P-PL AP AA AM AL PL S H 8423 (holotype) 45 62 23 23 12 35 14 15 5 31 25 36 72 32 8424 (EGD-7) 49 62 26 24 8 32 12 15 5 29 25 34 - 27 8419 (EGD-1) 42 56 22 21 9 30 14 11 5 26 22 29 58 - 8417 (EGD-6) 41 52 22 19 13 32 12 13 5 - 15 22 52 20 8421 (EGD-8) 40 54 23 23 11 33 14 14 5 26 16 24 54 20

continued.

Slide D min D max V min V max pa pm pp Ip DS VS NDV TaIII TaW 8423 (holotype) 29 37 29 36 315 290 337 941 - - - 95 11 8424 (EGD-7) 29 34 19 32 295 261 304 860 38 15 53 86 11 8419 (EGD-1) 29 34 20 30 283 230 274 787 - - - 77 10 8417 (EGD-6) 20 23 16 24 248 211 252 711 35 17 52 70 10 8421 (EGD-8) 20 23 - - 256 230 268 754 - - - 70 10 FIGURE 1. Arabapolonia omanensis gen. nov. et sp. nov. A, scutum and eyes of holotype; B, dorsal idiosomal seta of 1st row in holotype; C, dorsal idiosomal seta of 1st row in specimen No. 8421; D, ventral idiosomal seta in holotype; E, ventral idiosomal seta in specimen No. 8421; F, arrangement of dorsal idiosomal setae; G, arrangement of ventral idiosomal setae. Scale bars: 50 μm (A), 20 μm (B–E), 100 μm (F, G).

Description (larva). IDIOSOMA. Eyes large, 2 + 2; eyes of anterior and posterior pair separated, ocular plate absent. One or 2 pairs of humeral setae (marginal idiosomal setae of 1st dorsal row may be considered as second pair of humeral setae), 33–36 moderately barbed dorsal idiosomal setae, fD=2H- 10-8-8 (7)-6-4(2); 2 sternal setae between leg coxae II and 4 sternal setae between leg coxae III; 15–17 ventral setae; total number of idiosomal setae excluding coxal and sternal 52–53.

GNATHOSOMA. Cheliceral blade with 1 inconspicuous denticle near apex, without tricuspid cap; cheliceral base with few puncta in proximal part; gnathobase with sparse puncta and transverse cuticular striations, with 1 pair of branched setae; tracheae extend from gnathobase to leg coxa I, spiracles not found; palpal femur and genu with few puncta; galeala nude or having one small cilium; palpal claw single; setae on palpal femur and genu branched; ventral and lateral palpal tibial setae branched, dorsal palpal tibial seta heavily barbed in distal half, in shape of tooth-brush; palpal tarsus with 6 non-specialized setae (3 setae definitely branched and 3 setae seem nude), nude subterminala and tarsala.

SCUTUM. Nearly hexagonal, with large, rounded anterior projection, without nasus, posterior scutal margin slightly prominent, angulated or rounded, with few cuticular striations; 2 anteromedian setae, 2 anterolateral and 2 posterolateral setae situated on scutum; AM bases at level of ALs; SB slightly posterior to level of PLs; PL> AM> AL; flagelliform sensilla heavily branched in distal half.

LEGS. All 7-segmented, with 1 pair of claws and claw-like empodium; claws with 1–2 long onychotriches, almost as long as claw itself. Leg I: coxa with 1 non-specialized branched seta (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 4B, two genualae, microgenuala; tibia 7B, two tibialae, microtibiala; tarsus 23B, tarsala 16–22 long, with sparse annulation, microtarsala distal of tarsala; subterminala, parasubterminala and pretarsala absent. Leg II: coxa without seta; trochanter 1B; basifemur 2B; telofemur 4B; genu 3B, genuala, without microgenuala; tibia 6B, 2 tibialae; tarsus 15B, tarsala 19–26 long, very thin, with sparse annulation and bulbiform apex, microtarsala distal of tarsala, pretarsala absent. Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala; tibia 4B, tibiala absent; tarsus 15B, mastitarsalae absent.

Type material. Holotype larva ( ZISP collection number 8423, T-Tr.-56) ex Hemidactylus lemurinus (Sauria: Gekkonidae ) (mite Id S7609, tube No. EGD-3), OMAN: Dhofar Governorate, Wadi Ayoun (locality No. 1 according to above list), 17.24218 N, 53.89095 E, 678.8 m a.s.l., 1 May 2011, coll. S. Carranza and E. Gómez- Díaz; 1 larva paratype (8419) ex H. homoeolepis (S7673, EGD-1), Ash Sharqiyah Region, 2 km W from Qumaylah (locality No. 2), 21.95181 N, 59.6082 E, 42 m a.s.l., 10 October 2010, coll. S. Carranza; 1 larva paratype (8424) ex Ptyodactylus hasselquistii (Sauria: Phyllodactylidae ) (S7652, EGD-7), Ash Sharqiyah Region, Wadi Tiwi (locality No. 3), 22.75737 N, 59.09399 E, 1196.5 m a.s.l., 7 May 2011, coll. S. Carranza and E. Gómez-Díaz; 2 larva paratypes (8417 and 8418) ex Pristurus rupestris (Sauria: Sphaerodactylidae ) (S7270, EGD-6), Ad Dakhiliyah Governorate, 8 km N of Tanuf, Jebel Akhdar (locality No. 4), 23.12441 N, 57.45664 E, 1742.7 m a.s.l., 10 May 2011, coll. S. Carranza and E. Gómez-Díaz; 2 larva paratypes (8421 and 8422) ex Pristurus rupestris (S7251, EGD-8), Al Batinah Region, Haat Village, Jebel Akhdar (locality No. 5), 23.17711 N, 57.41018 E, 1307.7 m a.s.l., 8 May 2011, coll. S. Carranza and E. Gómez-Díaz.

Type deposition. Holotype and paratypes are deposited in the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia.

Etymology. The species epithet refers to the Sultanate of Oman where the type locality is situated.

Remarks. Size differences within the examined material are very significant. First two specimens in Table 1 (Nos 8423 and 8424) have the widest scutum (measurements AW and PW), longest setae (AM–V max) and longest legs (pa–Ip and TaIII). Other two specimens (Nos 8417 and 8421) are the smallest, and specimen No. 8419 occupies the intermediate position. It is remarkable that the dorsal idiosomal setae in the largest specimens are almost twice longer than those in the smallest specimens (compare Fig. 1 B and C) and the legs of the holotype are 1.3 times longer than the legs of the smallest specimen (Ip = 941 vs. 711). In view of the fact, that non-metric characters are identical in all examined specimens, we consider these differences to be an individual variation. Dependence of size parameters on climatic factors was repeatedly recorded in chigger mites (e.g. Stekolnikov 1998, 2002; Stekolnikov & Klimov 2010); revealing of such variability is very natural in generally hot and dry climate of Oman. It is noteworthy that two smallest specimens (Nos 8417 and 8421) were collected in the places having the same ecological characteristics—localities 4 and 5, respectively. They are situated in the mountains, at elevations higher than in other collection localities (1743 and 1308 vs. 679, 1197, and 42 m), and in more wet local climate.