Schizocyrtillus fuzhouensis, Xu & Li & Zhang, 2019

Xu, Yun, Li, Xiang & Zhang, Fei-Ping, 2019, Two new records of the Family Celaenopsidae (Acari: Mesostigmata) from China, with description of a new species, Zootaxa 4604 (2), pp. 326-334 : 327-333

Schizocyrtillus fuzhouensis sp. nov.

Diagnosis. Adult female. Dorsum oval, truncate anteriorly and broadly rounded posteriorly; smooth, covered with more than 100 simple setae and numerous irregularly placed small circular pores; sternal plate with three pairs of simple setae, two pairs of pores and network of sculpture lines; metasternal plates narrow, lying between coxae II and III, bearing one pair of setae; ventral, anal, parapodal and metapodal shields fused, forming genito-ventrianal shield; anterior margin of this shield convex, with notched protuberance medially; its surface smooth, with 28 pairs of simple setae and numerous irregularly placed circular pores; post-anal plate more than six times as wide as long, with one pair of setae.

Type material. Holotype Female, China, Lianjiang county, Fuzhou city, Fujian province, 27 October 2016, by Yun Xu, from rotten wood and bark of Pinus massoniana Lamb . Paratypes: 1 female, same data as holotype. The holotype and paratype are deposited in the Department of Plant Protection , Fujian Agriculture and Forestry University, China .

Female (n=2).

Idiosomal dorsum ( Fig. 5 ): Shape oval, truncate anteriorly and broadly rounded posteriorly, 540 length, 395 at width level of coxae IV; smooth, covered by a single shield with more than 100 simple setae; all setae subequal in length (25–35); surface with numerous irregularly placed small circular pores. Marginal plate with a single row of simple setae.

Idiosomal venter ( Fig. 6 ). Tritosternal base adjacent to anterior margin of sternal plate, laciniae free and pilose. Sternal shield wider than long, both anterior and posterior margins concave. Sternal plate with three pairs of simple setae (st 1 – st 3), st 1 placed anteriorly and st 2 – st 3 inserted at the same level posteriorly, shield with two pairs of pores, and a network of sculpture lines. Metasternal plates narrow, lying between coxae II and III, bearing setae st 4. Pore III slit-shaped, located anterior to setae st 4. Posterior margins of metasternal plates sinuous, with heavily sclerotised indentations to accommodate heads of vaginal sclerites. Ventral, anal, parapodal, peritremal and metapodal shields fused, forming genito-ventrianal shield. Anterior margin of this shield convex, with notched protuberance medially. Shield surface smooth, with 28 pairs of simple setae and numerous irregularly placed circular pores. Stigmata lateral to coxae IV. Peritremes straight, extending to anterior margin of coxae II. Ventrimarginal shields border ventrianal shield from level of coxae II to posterior margin; shields posteriorly separated from one another by post-anal plate. Each ventrimarginal shield with three simple setae posteriorly. Postanal plate (16 length, 105 width) more than six times as wide as long, with one pair of setae.

Legs ( Fig. 7 ). All legs with simple setae. Leg I without claws. Leg II much stouter than others. Genua III and IV each with one dorsal macroseta. Leg I–IV chaetotaxy (from coxa to tarsus): I 2-5-9-9-12 -31; II 1-4-12-9-7 -19; III 1- 4-7-8-7-18; IV 0-5- 4-8-7-21.

Gnathosoma ( Figs 8–10 ). Tectum as in Fig. 9 . Fixed digit of chelicera with two teeth on the cutting edge and 13–14 teeth on the lateral face. Movable digit with eight teeth, last tooth much larger than others; with two branched excrescences ventrally. Hypostome with four pairs of setae; corniculi deeply divided and trifurcate.

Male and immatures unknown.

Etymology. The species is named after the type locality, Fuzhou.

Remarks. The adult female of Schizocyrtillus fuzhouensis sp. nov. is easily distinguishable from those of the other three species by the following: dorsal dorsum smooth, lacking big pores (dorsal dorsum smooth, covered with three to four pairs of big pores in Schizocyrtillus lathrius Kinn, 1970 and Schizocyrtillus rarus Khaustov, 1999 , dorsal dorsum covered with reticular ornamentation, lacking big pores in Schizocyrtillus josefinae Gwiazdowicz, 2002 ); genito-ventrianal shield smooth, with 28 pairs of simple setae (shield smooth, with 17 pairs of setae in S. lathrius and 31 setae in S. rarus , shield with reticular ornamentation and 14 pairs of setae in S. josefinae (according to the Fig. 2 in Gwiazdowicz, 2002); post-anal plate more than six times as wide as long (post-anal plate about 1.5 times as wide as long in S. lathrius , four times as wide as long in S. josefinae and three times as wide as long in S. rarus ).

Figures

FIGURES 5. Schizocyrtillus fuzhouensis sp. nov. (adult female). dorsal view of the body. Scale bar: 50 µm.

FIGURES 6. Schizocyrtillus fuzhouensis sp. nov. (adult female). ventral view of the body. Scale bar: 50 µm.

FIGURES 7. Schizocyrtillus fuzhouensis sp. nov. (adult female, left side legs in dorsal view). Leg I–IV. Scale bar: 50 µm.

FIGURES 8–10. Schizocyrtillus fuzhouensis sp. nov. (adult female). 8, gnathosoma (venter); 9, tectum; 10, chelicera. Scale bar: 50 µm.

FIGURES 1–4. Pleuronectocelaeno barbara. 1–2. female, dorsal and ventral views, respectively; 3–4. male, dorsal and ventral views, respectively. Scale bar: 100 µm.