Phthiracarus species (Acari: Oribatida: Phthiracaridae) from New Zealand, with description of a new species, redescription of Phthiracarus pellucidus and a key to 19 described species from the Australian Region Author Liu, Dong Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, P. R. China; Author Zhang, Zhi-Qiang Landcare Research, Auckland, New Zealand; & Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland, Auckland, New Zealand text Journal of Natural History 2016 J. Nat. Hist. 2016-03-10 50 1463 1472 http://dx.doi.org/10.1080/00222933.2016.1145275 journal article 10.1080/00222933.2016.1145275 1464-5262 5206417 Phthiracarus minutus sp. nov. ( Figure 1 ) Diagnosis Surface of idiosoma densely punctate; median carina and lateral carinae absent; median sigillar fields narrow, longer than laterals; sensilli short, broad proximally and slightly narrow in the distal; other prodorsal, notogastral and ano-adanal setae minute and fine; setae c 1–2 farther away from anterior border, setae c 3 close; vestigial setae f 1 posterior to setae h 1 ; four pairs of lyrifissures ia, im, ip and ips present; h < h–h ; genital plates with oblique lines not reaching inner margin; formula of genital setae: 9(4 + 5): 0; adanal setae situated close to paraxial margin; setae d on femora I situated near distal end of article; setae v’ on femora I absent. Figure 1. Phthiracarus minutus sp. nov. : (A) lateral view of body (legs removed); (B) prodorsum, dorsal view; (C) sensillus, dorsal view; (D) left side of ventral plate; (E) subcapitulum, palpi removed; (F) palp, antiaxial view; (G) chelicera, antiaxial view; (H) femur I; (I) tibia IV. Scale bars: A, B, D = 100 μm; C, E–I = 50 μm. Description Measurements. Holotype : Prodorsum: length 351, width 235, height 130, setae: ss 50, ro 10, le 10, in 10, ex 20; notogaster: length 598, width 460, height 462; setae: c 1 20, d 1 20, e 1 20 , h 1 18, ps 1 18; ventral region: ad 3 15, an 1 7, an 2 7; genito-aggenital plate 102 × 210, ano-adanal plate 126 × 261. Paratype : Prodorsum: length 305, width 206, height 120; notogaster: length 490, width 422, height 405. Integument. Colour greyish-yellow. Surface of idiosoma densely punctate. Prodorsum ( Figure 1A–C ). Median carina, lateral carinae and posterior furrows absent; sigillar fields distinct, median region narrow, longer than lateral regions; sensilli short and smooth, broad proximally and slightly narrow in the distal; other prodorsal setae minute and fine; comparative length: ss > ex > in = le = ro ; mutual distance: in – in / ro – ro ≈ 4. Notogaster ( Figure 1A ). 15 pairs of setae present, minute ( c 1 <1/5 c 1 – d 1 ) and fine; setae c 1–2 farther away from anterior border, setae c 3 close; three pairs of elongated insertion prints present on the roots of setae ps 2 – ps 4 ; vestigial setae f 1 posterior to setae h 1 ; four pairs of lyrifissures ia, im, ip and ips present. Venter ( Figure 1A, D–G ). Setae h of mentum shorter than distance between them. Genital plates with oblique lines not reaching inner margin; nine pairs of genital setae present, arranged in two rows with formula: 9(4 + 5): 0; anoadanal plates each with five minute setae; adanal setae situated close to paraxial margin, setae ad 1 closest and ad 3 furthest. Legs ( Figure 1H–I ). Setal counts for leg segments (without tarsi): I: 1–3–2(2)–5(1); II: 1–3–2(1)–3(1), III: 2–2–1(1)–2(1), IV: 2–1–1–2(1); setae d on femora I situated near distal end of article; setae v’ on femora I absent; setae a” on tarsi I and setae ft” on tarsi II curved distally; setae a” on tarsi II curved distally; setae s and pv’ on tarsi IV present; setae s on tarsi I and II present. Material examined Holotype : adult (in alcohol, 72/227), New Zealand : Red I. Mercury Is. Cl. , from litter, 24 November 1972 , leg. G.W. Ramsay. Paratype : one adult (in alcohol, 72/227), same data as holotype . Etymology Named after the minute notogastral setae. Remarks This new species is very easily distinguishable from all congeneric species of this genus by the following combination of features: sensilli short and slightly narrow distally; all other setae minute and fine; vestigial setae f 1 posterior to setae h 1 ; four pairs of lyrifissures ia, im, ip and ips present; formula of genital setae: 9(4 + 5): 0; setae v’ on femora I absent. Redescription of known species