Paralycus nortoni, Xu & Zhu & Wu & Zhang, 2020

Xu, Yun, Zhu, Yu-Zhen, Wu, Jie-Qin & Zhang, Fei-Ping, 2020, A new species of the genus Paralycus from Fujian, China, Acarologia 60 (2), pp. 481-487 : 482-486

Paralycus nortoni sp. nov.

Zoobank: CCED3053-E61E-484C-8161-BD3F45F11020

( Figures 1–3 )

Diagnosis — Adult female. Minute and elongate, weakly sclerotized. Idiosoma with a distinct humeral sulcus; propodosoma with 5 pairs of setae and a single pair of clavate bothridial organs; notogaster divided into 4 regions by 3 transverse dorsal sutures, covered with fine longitudinal striae. Venter each with one pair of setae between coxae I, coxae II, coxae

III and without setae between coxae IV. Genital region with 2 pairs of discs and five pairs of genital setae. Setae g 1, g 2 and g 3 minute and subequal in length, g 4 and g 5 subequal in length and about twice as long as g 1. Claws absent on all tarsi, each tarsus with a minute empodial remnant and caruncle-like membrane.

Type material — Holotype Female, China, Minhou county, Fuzhou city, Fujian province,

17 Apr. 2019, by Yu-Zhen Zhu, Jie-Qin Wu and Yun Xu, ex. the barks of Pinus massoniana Lamb attacked by Monochamus alternatus . Paratypes: 1 female, same data as holotype.

Type deposition — The holotype and paratype were deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing ( NZMC)

and the Department of Plant Protection, Fujian Agriculture and Forestry University ( FAFU), respectively.

Female (n=2)

Gastronotic region ( Fig. 1A ): Body minute and elongate, colorless when alive. Length of gastronotic region 210–215, width 55–65. Prodorsum covered with shield-shaped plate in middorsal region, bearing 2 pairs of setae ro (and le); 3 pairs of setae (exa, exp and in) and one pair of clavate bothridial organs ss in the dorsolateral area of prodorsum. Setae le about twice as long as ro, in about twice as long as exa, and exp minute, lengths ro 13–14, le 30–31, exa 22–23, exp 5, in 42–44, ss 17. Notogaster divided into 4 regions by 3 transverse dorsal sutures. Notogaster covered with fine longitudinal striae, bearing 4 pairs of setae c 1 (, c 2, c 3 and cp) in the region of segment C, 4 pairs of setae d (1, d 2, e 1 and e 2) in the region of segment DE, 2 pairs of setae (f 1 and f 2) in the region of segment F, and 6 pairs of setae h 1 (, h 2, h 3, ps 1, ps 2 and ps 3)

in the region of segment H and PS. Lengths of notoastral setae c 1 22–24, c 2 28–29, c 3 34–35,

cp 29–34, d 1 17–18, d 2 24–26, e 1 22 –23, e 2 24 –27), f 1 32–34, f 2 32–39, h 1 32–39, h 2 37–39,

h 3 32–35, ps 1 27, ps 2 53–56, ps 3 14–15.

Gnathosoma ( Figs. 1B , 2A ). Gnathobase with rutella and 4 pairs of setae along midventral line plus one seta proximal to trochanter on coxal base of palp. Palp simple, with 4 free segments, setal formula: 0, 2, 1, 7.

Ventral region ( Figs. 1B , 2B ). Venter each with one pair of setae between coxae I, coxae

II, coxae III and without setae between coxae IV; setae between coxae II about twice as long as setae between coxae I, setae between coxae III minute. Venter of opisthosoma with 2 pairs of acetabula, 5 pairs of genital setae (g 1, g 2, g 3, g 4 and g 5), 3 pairs of adanal setae (ad 1, ad 2 and ad 3). Setae g 1, g 2, g 3 minute and subequal in length, g 4, and g 5 subequal and about twice as long as g 1. Lengths: g 1 3, g 2 3–4, g 3 3–4, g 4 7–8, g 5 8, ad 1 14–15, ad 2 53–58, ad 3 11–13.

Legs ( Fig. 3 ). Legs relatively short, measurements (total length from trochanter to tarsus, pretarsus excluded): I 50–55, II 45–48, III 45–48, and IV 50–52. Leg structure simple with highly visible segments, as shown in the Fig. 3 . Claws absent on all tarsi, each tarsus with a minute empodial remnant and caruncle-like membrane. Setation of legs I–IV (from trochanter to tarsus, solenidia in brackets): leg I 0-2-4-3 (1)-8 (1); leg II 0-2-3-3 (1)-7 (1); leg III 1-2- 0-3(1)-5 and leg IV 0-2-0-2-5. Dorsal, ventral and lateral setae on trochanter, femora, genua and tibiae I–IV simple and filiform. Solenidion φ on tibiae I–II elongate, attenuate, on tibia III baculiform. Unguinal setae u and proral setae p on tarsus I–IV simple. Only p ’’ on tarsus I; seta s on tarsus I simple. Solenidion ω on tarsi I–II baculiform, ω on I about twice the length of that on II.

Male unknown.

Etymology — The species is named after Dr. Roy A. Norton, a distinguished acarologist who made significant contributions to the systematics of Oribatida .

Remarks — Paralycus nortoni sp. nov. is easily distinguishable from other species by the following features: Venter without setae between coxae IV (vs. with one pair of setae between coxae IV in P. chongqingensis , P. lavoipierrei , P. longior , P. parasiti and P. raulti ); venter of opisthosoma with 5 pairs of genital setae (vs. with 3 pairs of genital setae in P. chongqingensis ,

P. lavoipierrei and 4 pairs of genital setae in P. parasiti , P. parvulus and P. raulti ); trochanters 0-

0-1-0 (vs. 0-0-0-0 in P. parvulus ); genua 4-3-0-0 (vs. 4-2-0-0 in P. lavoipierrei and P. parvulus );

tarsi 7+ω-6+ω-5-5 (vs. 9+ω-6+ω-5- 5 in P. chongqingensis and P. longior ). The identification characters of P. pyrigerus are not listed because the morphological details were not given by

Berlese (1905), but the differences in size (213 μm for P. nortoni sp. nov. vs. 170 μm for P.

pyrigerus), habitat (barks of pine for P. nortoni sp. nov. vs. soil for P. pyrigerus ) and collection locality ( China for P. nortoni sp. nov. vs. Italy for P. pyrigerus ) suggest that P. nortoni sp. nov.

and P. pyrigerus are distinct species.

The known species of Paralycus are described from soil, bees, Auricularia sp. , lily fruits,

and Coccinella septempunctata . Among them, two species are described as phoretic mites: P.

parasiti and P. raulti ( Berlese, 1905; Lavoipierre, 1946; Price, 1973; Fan et al. 1996; Zhang and Li, 2001). Despite of being collected from the barks of beetle-infested pines, the new mite species P. nortoni sp. nov. was not detected on the eggs, instars or mature beetles at the site, nor obvious interaction was noted between them. Up to date, there are five species of mesostigmatid mites, including Dendrolaelaps fukikoae , D. unispinatus , Proctolaelaps hystrix ,

Mucroseius nipponensis and M. squamosus , which were found to coexist in the pupal chambers of the beetle M. alternatus ( Tamura and Enda, 1980; Kinn, 1987; Lindquist and Wu, 1991);

and one species of prostigmatid mite Paracarophenax alternatus distributed around the coxal cavity of the adult and feeding on the egg M of. alternatus ( Xu et al. 2018) . No significant morphological body adaptations to aid in phoresy, such as attachment devices (hook-like claws on legs), were found neither on this new species, nor on P. parasiti and P. raulti . With that said,

it remains an interesting topic whether this new species is phoretic on beetles or share the same host preference with beetles.

Notes — In the holotype, one seta h 3 was duplicated h (3 and h 3x in Fig. 1B and 2B )

Figures

Figure 1 Paralycus nortoni sp. nov. (adult female). A – dorsal view; B – ventral view.

Figure 2 Paralycus nortoni sp. nov. (adult female). A – ventral view of gnathosoma; B – genitalanal region.

Figure 3 Paralycus nortoni sp. nov. (adult female, right side legs in dorsal view). A – leg I; B – leg II; C – leg III; D – leg IV.