Novonothrus silvanus, Colloff, Matthew J., 2011

Colloff, Matthew J., 2011, A review of the oribatid mite family Nothridae in Australia, with new species of Novonothrus and Trichonothrus from rain forest and their Gondwanan biogeographical affinities (Acari: Oribatida), Zootaxa 3005, pp. 1-44 : 20-25

Novonothrus silvanus sp. nov.

(Figs. 11, 12a–c, 13, 14, 17e, 18e)

Novonothrus n. sp. A: Palmer & Norton, 1991, 79.

Dimensions. Holotype female length 972 μm, breadth 585 μm. Paratype females (n = 14) mean length 965 μm (range 934–995 μm), mean breadth 567 μm (range 500–608 μm); paratype males (n = 10) mean length 842 μm (range 808–869 μm), mean breadth 464 μm (range 444–480 μm).

Female. Prodorsum: Median light oval region 20 μm long 33 μm broad, rectangular ridge medial of lateral light oval regions (each 35 μm long, 22 μm broad). Rostral setae (ro) straight, smooth, spiniform, 28 μm long (Fig. 11a). Lamellar seta (le) 56 μm long, smooth, straight, thick, spiniform, on squat tubercle positioned equidistantly between midline of prodorsum and lateral margin. Prodorsum expanded laterally in region posteriolateral of le. Interlamellar seta (in) 64 μm long, straight, smooth, spiniform, pointed, extending as far as dorsosejugal furrow. Bothridial rim rounded, with anterior ridge extending towards lamellar seta; with faint, curved transbothridial line. Exobothridial seta ex 1 short, spiniform. Bothridial seta (bs) flagelliform, smooth, 285 μm long, apex reflexed. Prodorsum alveolate.

Notogaster: Ratio of length to breadth 1.29; notogaster sub-rectangular; margins sub-parallel; caudal margin rounded, convex (Fig. 11a). Notogastral cuticle with very small, elongate, angular alveoli (3–10 μm diameter; Fig. 17 e), sparsely-distributed (9–17 μm apart). Setae of c -f series and p 2-3 straight or slightly curved, pointed, smooth, 59–78 μm long, except shorter seta c 1 and c 2 (41–44 μm). Distance between setae c 1 equal to that between c 1 and c 2; distance between setae c 1 0.6 × that between d 1; distance between d 2 1.8 × that between d 1; distance between e 1 0.9 × that between f 1. Setae of h series and p 1 barbed, covered in narrow, phylliform cerotegument (Fig. 11d). Caudal margin rounded without crenellations. Longitudinal ridge absent from either side of notogaster.

Subcapitulum: Mentum foveolate. Gena with four setae: a and m 1-3, a twice the length of others (Fig. 11b); coxal spine (e) present. Palp setal formula (solenidion in brackets) 0-1-1-3-9(1). Palp tarsus short, rounded apically ( Fig. 12 b). Adoral setae ad 1 and ad 2 sub-equal in length, curved, isodiametric, blunt apically ( Fig. 12 c).

Coxisternum: Epimeral plates separated along sternal line; III and IV further apart than I and II (Fig. 11b). Epimeral setal formula: 6-5-6-5; setae smooth, thin, 20–33 μm long; those of epimeral plates I–III setiform; those of IV thicker, spiniform. Setae on epimeral plates I–III positioned along anterior and medial part of plate; those of plate IV predominantly on posterior part of plate. Epimeral plates IV broadly triangular, with triangular posteriomedian spur adjacent to genital plate.

Anogenital Region: Each genital plate 167 μm long, 95 μm broad, with nine smooth, setiform setae 22–36 μm long: six setae in median file (four on anterior part of plate) and three in lateral file (one on anterior part of plate; Fig. 11b). Pre-anal plate narrow, sub-triangular, 140 μm broad. Each anal plate 268 μm long, 50 μm broad, with two smooth, spiniform setae, 31 μm long; one on anterior, one on posterior part of plate. Adanal setae subequal in length and shape to anal setae. Ventral margin of notogaster posterior of anal plates entire, convex, shield shaped.

Lateral View: Anterior prodorsal margin curved; lateral expanded region extending as far as mentum (Fig. 11c). Seta le projecting beyond base of ro. Seta ex just dorsal of abjugal furrow. Alveolus of ex 2 absent. Interbothridial region strongly convex. Notogastral shield convex between setae c 1 and f 1. Ratio of notogastral height to length 0.61. Lateral notogastral ridge absent. Opening of opisthonotal gland posterior of seta f 2, prominent, slit-like, surrounded by circular ridge of cuticle.

Legs: Pre-tarsus monodactylous. Femur I 170 μm long; setae sparingly barbed; seta d slightly longer (70 μm) than others in l series (51–58 μm; Fig. 18 e). Legs I and II with oval, porose regions on paraxial surfaces of proximal segments ( Fig. 13 ). Setal formulae (solenidia in brackets): Leg I 1-9 -5(1)-6(2)-39(3); Leg II 1-7 -5(1)-5(1)- 27(1); Leg III 2-6 -5(1)-5(1)-23; Leg IV 1-6 -5(1)-5(1)-21 ( Fig. 13 ).

FIGURE 11. Novonothrus silvanus sp. nov., holotype female; a) dorsal; b) ventral; c) lateral; d) detail of seta h 1.

Deutonymph. Length 591 μm, breadth 303 μm. Prodorsum: Length 194 μm. median light oval region 14 μm long 20 μm broad, with transverse ridge between rostral setae; lateral light oval regions 19 μm long, 15 μm broad (Fig. 14a). All prodorsal setae covered in bacilliform cerotegument. Rostral seta (ro) straight, smooth, spiniform, 25 μm long. Lamellar seta (le) 17 μm long, spiniform, smooth, on squat, conical tubercle towards lateral margin of prodorsum. Interlamellar seta (in) spiniform, smooth, 27 μm long. Bothridium with anterior ridge extending towards lamellar seta. Bothridial seta (bs) elongate, flagelliform, 206 μm long. Exobothridial seta (ex) spiniform, short (12 μm) protruding from posteriolateral margin of bothridium. Prodorsum reticulate.

Gastronotic Region: Length 397 μm. Gastronotic region sub-rectangular (Fig. 14a). Cuticle slightly tuberculate with cerotegument of crenellated plaques (Fig. 14c). Setae covered with broad, flat cerotegument. Setae 24–35 μm long, except h 2 longer (41 μm); those of c -f series sparingly barbed, h-p series densely barbed. Distances between bases of each seta c 1, d 1, and f 1 sub-equal; distance between bases of each seta d 2 and each e 1 1.5 × wider. Caudal margin incised lateral of setae p 1.

Subcapitulum: Mentum foveolate; Gena with setae a and m 1-2 (Fig. 14b)

FIGURE 14. Novonothrus silvanus sp. nov., deutonymph; a) dorsal; b) ventral; c) cerotegument in the vicinity of seta f 1.

Coxisternum: Epimeral plates separated along sternal line by unsclerotised longitudinally striate cuticle (Fig. 14b). Epimeral setal formula 4-3-3-2. Epimeral setae thin, smooth, setiform, 8–13 μm long, except 4b slightly longer (20 μm), and stouter. Setae on epimeral plates I–III positioned on medial part of plate, those of plate IV near posterior margin of plate. Epimeral plates IV lacking triangular posteriomedian flange adjacent to genital plate.

Anogenital Region: Each genital plate 48 μm long, 22 μm broad, not divided transversely (Fig. 14b), with four smooth, setiform setae, 14–18 μm long. Genital plates surrounded by striate cuticle. Each anal plate 136 μm long, 24 μm broad, smooth. Adanal setae spiniform, smooth, 20–24 μm long.

Material examined. Holotype female, ten paratype females, six paratype males, ANIC 4016, moss on trunk of Sassafras ( Atherosperma moschatum ), cool temperate rain forest, Errinundra Saddle, Errinundra National Park, Victoria, 37°19'18"S 148°51'11"E, 1030 m., coll. M.J. Colloff, 30.v.2009. One paratype female, from moss ( Dicranoloma billiardieri ), Nothofagus cunninghami forest, The Beeches, Lady Talbot Drive near Warburton, Yarra Ranges National Park, Victoria, 37°29'14"S 145°49'59"E, 800 m., coll. G. Perdomo, May 2009. Two paratype males, sieved leaf litter, Eucalyptus forest, walking track to Eurobin Falls, Mount Buffalo National Park, Victoria, 36°43'3"S 146°50'30"E, 460 m, coll. D. Black. Three paratype females, FM (HD) 80-175 [SR 249], litter, Eucalyptus forest with tree ferns, Coranderrk Bushland Reserve, S.E. of Healesville, Victoria, 37°41'S 145°31'E, ca. 240 m., A. Newton & M. Thayer, 13.i.1980. Non-type material: two nymphs, Mount Buffalo National Park, three nymphs, Eurobin Falls, two nymphs, FM (HD) 80-175 [SR 249]. Holotype and paratypes from Errinundra, The Beeches and Mount Buffalo deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra. Two paratypes from Errinundra in Roy A. Norton Collection, College of Environmental Science and Forestry, State University of New York, Syracuse. Other paratypes in Field Museum, Chicago.

Etymology. The specific name is from the Latin, Silvanus , a Roman god of the woods and forests, alluding to its macrohabitat and type locality amongst temperate rain forest at Errinundra.

Remarks. Novonothrus silvanus sp. nov. differs from other members of the genus by the following combination of characters: 1) prodorsum expanded laterally in region posterior of lamellar setae into prominent bulges; 2) interlamellar setae smooth, spiniform; 3) notogastral cuticle with small, angular, sparsely-distributed alveoli; 4) notogastral setae of c -f series and p 2-3 smooth, thin, spiniform; 5) notogastral setae h 1, h 2 and p 1 barbed, covered in broad, phylliform cerotegument; 6) considerably greater distance between setae d 2 than between d 1 and between h 1 than f 1; 7) caudal margin smooth, rounded; 8) notogaster without lateral longitudinal ridges; 9) Tarsus I with 39 setae.

Novonothrus silvanus is morphologically most similar to N. barringtonensis and N. nothofagii , as described above.

Figures

FIGURE 12. Novonothrus silvanus sp. nov., paratype female; a) subcapitulum; b) palp tarsus; c) adoral setae; d) N. barringtonensis sp. nov., paratype female, adoral setae; e) N. glabriseta sp. nov., paratype female, adoral setae; f) N. coronospinosus sp. nov., adoral setae; g) N. nothofagii sp. nov., adoral setae; h) N. glabriseta sp. nov., paratype female, detail of rostrum.

FIGURE 13. Novonothrus silvanus sp. nov., paratype female; legs, left, paraxial aspect; a) Leg I; b) Leg II; c) Leg III; d) Leg IV.

FIGURE 17. Detail of notogastral cuticle of Novonothrus spp.: a) N. barringtonensis sp. nov.; b) N. coronospinosus sp. nov.; c) N. glabriseta sp. nov.; d) N. nothofagii sp. nov.; e) N. silvanus sp. nov.; f) N. flagellatus Hammer, 1966.

FIGURE 18. Dorsal views of the right femur of Leg I of Novonothrus spp.: a) N. barringtonensis sp. nov.; b) N. coronospinosus sp. nov., c) N. nothofagii sp. nov., d) N. glabriseta sp. nov.; e) N. silvanus sp. nov.; f) N. flagellatus Hammer, 1966.