Podocinum guizhouense Yan & Jin

Yan, Yi, Jin, Dao-Chao, Guo, Xian-Guo & Guo, Jian-Jun, 2011, A new species of Podocinum Berlese (Acari: Podocinidae) and a key to species of the genus from China, Zootaxa 3001, pp. 49-56 : 50-54

Podocinum guizhouense Yan & Jin sp. nov.

( Figures 1–12 )

Types. Holotype female, Kuankuoshui National Nature Reserve, near Wangcao town (28°22’ N, 107°22’E), Suiyang County, Guizhou Province, China, 852 m a.s.l., 3. June. 2010, Yi Yan coll., in the fur of Niviventer fulvescens . Paratypes: 3 females, Kuankuoshui National Nature Reserve, near Qinggangtang town (28°29’N, 107°18’E), Suiyang County, Guizhou Province China. 746 m a.s.l., 11 August 2010, Wenqin Liang coll., in leaf litter.

Idiosoma. Colour orange-brown, shape oval.

Dorsal idiosoma ( Fig. 1 ). Dorsal shield extending posteriorly and laterally onto ventral surface; margins finely dentate, length 300–475, width at level of coxa III 270–335, widest point 280–344, behind coxa IV, surface ornamented with a series of dense oval and conical nodules arranged in a distinct polygonal network in pentagons or hexagons, whole shield covered with shallow punctate depressions, arranged in a large M-shaped pattern between j6 and J1. Shield bearing 17 pairs of setae, one pair (S4) of which in ventral position, second pair of podosomal dorsal setae (j2) and four pairs of opisthosomal setae (J3, Z1, Z3, Z4, S5) stout, long, pilose and with longitudinal striae on setal stem, other dorsal setae short but not simple, especially j3, j5, z6, j6 and J1 are visibly pilose. Shield with pairs of prominent pores, the most posterior pair (gdZ3) largest.

Ventral idiosoma ( Fig. 2 ). Tritosternum with short base and a pair of fine smooth laciniae ( Fig. 11 ). Pre-sternal plates absent. Endopodal shields fused with sternal shield between coxae I and II, free between coxae III and IV, two pairs of platelets internal to coxa IV resembling fragments of endopodal shields. Exopodal shields fused lateral to coxae II–IV. Sternal shield ornamented with smooth lines in polygonal pattern, length 61–63, width at narrowest part 86–94, anterior and posterior margins concave, shield with three pairs of pointed setae, pores inconspicuous. Posterior extension of sternal shield projecting deeply into the gap between coxae II and III. Metasternal shields small, kidney-shaped, with one pair of smooth pointed setae. Genital shield axe shape, indistinct anteriorly, truncate to slightly convex posteriorly, length 100–117, posterior width 123–132, with one pair of smooth pointed setae. Ventri-anal shield wider than long, length 125–147, anterior width 155–168, widest point 188–224, ornamented with weak transverse lines anteriorly; with four pairs of smooth pointed pre-anal setae; one pair of pores located between the third and fourth pre-anal setae, near the lateral margin; three circum-anal setae appreciably longer than anus, para-anal setae slightly behind mid level of but close to anus, postanal seta separated from anus. Separate metapodal plates absent. Peritremes extending anteriorly around the margin of the dorsal shield and are fused with dorsal shield at level of coxa II. Stigmata situated at level of coxa III; peritrematal shield extending posterior to level of anterior margin of ventri-anal shield, not reaching the level of the first pair of pre-anal setae.

Gnathosoma . Hypostome with six transverse rows of denticles, the anterior row curved, three pairs of smooth hypostomal setae: length h1 24.8, h2 8.3, h3 33.0, palpcoxal seta 19.0 ( Fig. 10 ). Fixed digit of chelicera with four large and three small teeth in two longitudinal lines. Movable digit with two prominent teeth ( Fig. 12 ). Epistome with three prongs branched at tip, the mid prong with five branches, lateral prongs with a few serrations on outer margin ( Fig. 9 ). Palp tarsal claw 3-tined.

Legs ( Figs 3–8 ). Length of leg I 1040 –1194 (tarsus 270–295), tarsus I with a pair of very long and whip-like terminal setae and a number of short associated setae, tarsal claw absent ( Fig. 5 ). Lengths of tarsus I terminal setae 396–495 and 254–268, lengths of sub-distal setae 8.8–10 and 7.5–9.0. Other legs much shorter and thicker, each bearing a pair of tarsal claws. Leg II 530–600, leg III 500–544, leg IV 545–632. All leg setae simple. Chaetotaxy: Leg I: coax 0 0/1 0/1 0, trochanter 1 1/1 0/2 1, femur 2 1/2 3/3 0, genu 2 1/1 3/1 2, tibia 2 1/1 1/2 2; Leg II coax 0 0/ 1 0/1 0, trochanter 2 0/1 0/1 1, femur 2 2/2 2/0 1, genu 1 1/0 2/1 2, tibia 1 1/1 1/1 2; Leg III coax 0 0/1 0/1 0, trochanter 1 1/1 0/1 0, femur 1 1/0 2/1 1, genu 1 1/0 2/1 2, tibia 1 1/1 1/1 2; Leg IV coax 0 0/1 0/0 0 0, trochanter 1 1/ 1 0/1 0, femur 1 1/1 2/0 1, genu 1 2/1 2/0 0, tibia 1 1/1 2/1 0.

Etymology. The new species is named after the type locality, Guizhou province.

Remarks. The new species resembles the species P. agilis Arutunyan, 1974 , P. pacificum Berlese, 1895 , P. tianmuense Liang, 1993 and P. catenum Ishikawa, 1970 ( Evans & Hyatt 1958; Athias-Henriot, 1959; Ishikawa, 1970; Arutunyan, 1974; Liang,1993), but they can be easily distinguished from each other by seven characters as showed in Table 1 .

and P. catenum .

Discussion. Ecological observations have shown that of species of Podocinum are predatory. Some podocinid mites have been recorded in rodent nests, such as P. anhuense and P. pacificum . Among them, P. anhuense was the first species of Podocinum reported from a cricetid nest. From the 3rd June 2010 to the 11th of August. 2010, we investigated the mite fauna in Kuankuoshui National Nature Reserve for a total of 10 days, during which we trapped 52 rodents. However, only the holotype was collected in the fur of a wild rodent ( Niviventer fulvescens ). The other specimens were all collected from the leaf litter. We cannot draw any conclusions about the relationship between the new species and the wild rodent on the basis of a single specimen. It may be just an accidental occurrence of one specimen on the rodent of the species that normally occurs in leaf litter.

Figures

FIGURE 1. Podocinum guizhouense sp. n. Adult female, dorsal shield. Scale represents 100 μm.

FIGURE 2. Podocinum guizhouense sp. n. Adult female, ventral idiosoma. Scale represents 100 μm.

FIGURES 3 – 8. Podocinum guizhouense sp. n. Adult female, legs: 3. trochanter-femur I; 4. genu-tibia I; 5. tarsus I; 6. trochanter-tarsus of leg II; 7. trochanter-tarsus of leg III; 8. trochanter-tarsus of leg IV. Scale represents 100 μm.

FIGURES 9 – 12. Podocinum guizhouense sp. n. Adult female. 9. epistome; 10. hypostome. 11. tritosternum. 12. chelicera. Scale represents 50 μm for 9, 100 μm for 10, 11, 12.

Tables

TABLE 1. Comparison of the new species, P. guizhouense sp. n., and four related species, P. agilis, P. pacificum, P. tianmuense

	P. agilis	P. pacificum	P. tianmuense P. catenum	P. guizhouense
Distance between bases of setae j1	Longer than seta j1	Shorter than seta j1	Longer than seta j1 Longer than seta j1	Longer than seta j1
Number of setae on dorsal shield	16 pairs	16 pairs	18 pairs 19 pairs	17 pairs