Macrogena hexasetosa, Ermilov, Sergey G. & Minor, Maria A., 2016

Ermilov, Sergey G. & Minor, Maria A., 2016, Three new species of oribatid mites of the family Punctoribatidae (Acari, Oribatida) from alpine bogs of New Zealand, Zootaxa 4092 (2), pp. 243-257 : 244-248

Macrogena hexasetosa sp. nov.

( Figs 1–10 )

Diagnosis. Body size: 381–398 × 232–249. Rostral setae ciliated, lamellar and interlamellar setae barbed. Bothridial setae short, clavate, slightly barbed. Dorsophragmata semi-oval. Four pairs of porose areas. Notogastral setae of medium size, setiform, indistinctly barbed. Epimeral and ano-adanal setae barbed. Epimeral setal formula: 3–1–2–2. Tridactylous. Tarsi I with 18 setae (l’’ and v’ absent), femora III with 2 setae (l’ absent).

Description. Measurements. Body length: 398 (holotype: female), 381–398 (12 paratypes: 2 females and 10 males); notogastral width: 249 (holotype), 232–249 (12 paratypes). No distinct differences in size between females and males.

Integument. Сolor brown. Body surface and legs punctate. Lamellae, translamella, pedotecta I and lateral parts of epimere I striate.

Prodorsum. Medial ledge of rostrum truncate, incisions deep. Lamellae (without cusps) half as long as prodorsum. Lamellar cusps are one third to one fourth the length of lamellae, without teeth. Rostral setae (ro, 45– 53) setiform, ciliated, directed antero-medially, inserted on small tubercles. Lamellar (le, 57–69) and interlamellar (in, 73–82) setae setiform, straight, barbed. Bothridial setae (bs, 28–32) clavate, with shorter (8–10) stalks smooth, longer (20–22) heads slightly elongated, rounded distally, slightly barbed. Exobothridial setae (ex, 10–12) thin, indistinctly barbed. Tutoria (tu) similar to lamellae in length, their cusps 3/5 length of tutoria, with one strong triangular tip directed to insertions of rostral setae.

Notogaster. Anterior margin slightly convex medially. Dorsosejugal porose areas distinct, oval, transversely elongated. Pteromorphs broadly rounded laterally. Dorsophragmata (D) semi-oval. Four pairs of rounded porose areas (Aa, A1 – A3, 10–12) with distinct borders. Notogastral setae (16–20) setiform, thin, indistinctly barbed. Lyrifissures ia, im, ip, ih and ips well visible. Opisthonotal gland openings (gla) located laterally to A1.

Gnathosoma . Subcapitulum longer than wide (94–102 × 73–82). Subcapitular setae a (16–20) shorter than m and h (both pairs 22–24), all setiform, slightly barbed. Adoral setae (or 1, or 2, 10) setiform, densely barbed. Palps (73–77) with setation 0–2–1–3–9(+ω). Setae e (6) spiniform. Axillary saccules slightly elongated. Chelicerae (106–110) with two setiform, barbed setae; cha (32–36) longer than chb (20–24). Trägårdh’s organ long, tapered.

Lateral podosomal and epimeral regions. Genal teeth (gt) well visible. Humeral porose areas Am and Ah large, oval. Custodia (cus) with short, pointed tips, slightly not reaching the level of anterior margin of pedotecta II. Discidia (dis) triangular. Circumpedal carinae (cp) distinct. Epimeral setal formula: 3–1–2–2. Setae 3c and 4c and their alveoli absent. Setae setiform, barbed; 1b and 1c (both pairs 24–28) longer than 3b (20–24), 4a and 4b (both pairs 14–18) and 1a, 2a and 3a (all three pairs 10–14). Setae 1b and 1c thickest, 4a and 4b thinnest.

Anogenital region. Genital (g 1, 16–20; g 2– g 6, 10–14), aggenital (ag, 12–16), anal (an 1, an 2, 12–16) and adanal (ad 1– ad 3, 12–16) setae setiform, slightly barbed. Adanal lyrifissures (iad) located close and parallel to anal aperture. Ovipositor elongated (134–138 × 41–49), blades (61–65) shorter than length of distal section (beyond middle fold; 73). Each of three blades with four straight, smooth setae, ψ1 ≈ τ1 (36–41) longer than ψ2 ≈ τ a ≈ τ b ≈ τ c (14–16). Six coronal setae (k, 10–12) straight, smooth.

Legs. Tridactylous. Median claws thicker than laterals, all serrate on dorsal side. Segments without ventral teeth. Regions of porose areas on femora and trochanters III, IV present, distinct. Formulas of leg setation and solenidia: I (1–5–3–4–18) [1–2–2], II (1–5–3–4–15) [1–1–2], III (2–2–1–3–15) [1–1–0], IV (1–2–2–3–12) [0–1– 0]; homology of setae and solenidia as indicated in Table 1 . Setae l’’ and v’ on tarsi I and l’ on femora III absent.

Roman letters refer to normal setae, Greek letters to solenidia (except ɛ = famulus). Single prime (') marks setae on anterior and double prime (") setae on posterior side of the given leg segment. Parentheses refer to a pair of setae. * – v' absent in Macrogena hexasetosa sp. nov.

Material examined. Holotype (female) and 2 paratypes (2 males): New Zealand, South Island, Central Otago, Old Man’s Range, 45°19'5.55"S, 169°11'56.13"E, 1625 m a.s.l., in wet moss of alpine bog, 17 February 2014 (M. Minor); 1 paratype (male): New Zealand, South Island, Central Otago, Old Man’s Range, 45°18'59.92"S, 169°11'49.13"E, 1637 m a.s.l., in wet moss of alpine bog, 17 February 2014 (M. Minor); 2 paratypes (1 female and 1 male): New Zealand, South Island, Central Otago, Pisa Range, 44°52'28.95"S, 169°10'23.71"E, 1777 m a.s.l., in wet moss of alpine bog, 18 February 2014 (M. Minor); 5 paratypes (1 female and 4 males): New Zealand, South Island, Central Otago, Pisa Range, 44°52'24.92"S, 169°10'34.53"E, 1809 m a.s.l., in wet moss of alpine bog, 18 February 2014 (M. Minor); 2 paratypes (2 males): New Zealand, South Island, Central Otago, Pisa Range, 44°51'59"S, 169°9'30.63"E, 1688 m a.s.l., in wet moss of alpine bog, 18 February 2014 (M. Minor).

Type deposition. The holotype and 3 paratypes are deposited in the New Zealand National Arthropod Collection, Auckland, New Zealand; 3 paratypes are deposited in the collection of the Senckenberg Institution, Frankfurt, Germany; 6 paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia.

Etymology. The specific name hexasetosa refers to the presence of six setae on each genital plate.

Comparison. The systematic position of Macrogena hexasetosa sp. nov. is problematic. This species has six pairs of genital setae (vs. five pairs in all other known Macrogena – see Ermilov & Minor, 2015(d )). However, we include the new species in Macrogena because other generic morphological traits are similar to this genus.

Macrogena hexasetosa sp. nov. is morphologically most similar to M. brevisensilla Ermilov & Minor, 2015 (d) from New Zealand in having tridactylous legs, four pairs of notogastral porose areas, punctate body surface and short bothridial setae. However, the new species differs from the latter by larger body size (381–398 × 232–249 vs. 315–332 × 182–199), the presence of six pairs of genital setae (vs. five), notogastral and ano-adanal setae of medium size (vs. minute, except c), setiform rostral setae (vs. dilated medio-distally), narrow tutorial cusps (vs. broadly rounded), the absence of antero-ventral teeth on genua I, II and femora II, and by the absence of striae on subcapitular mentum (vs. present).

Also, Macrogena hexasetosa sp. nov. is morphologically similar to Sphaerozetes clathratus (Hammer, 1967) from New Zealand; however, the new species differs from the latter by shorter, straight lamellar and interlamellar setae (vs. curved medio-distally), position of rostral setae dorso-laterally on prodorsum (vs. laterally), the absence of lateral tooth on lamellar cusps (vs. small lateral tooth present), and by connected dorsophragmata (vs. clearly separated).

Figures

FIGURES 1 – 4. Macrogena hexasetosa sp. nov., adult: 1 — dorsal view; 2 — ventral view (legs not shown); 3 — subcapitulum, ventral view; 4 — ovipositor. Scale bar 100 Μm (1, 2), scale bar 20 Μm (3, 4).

FIGURES 5 – 10. Macrogena hexasetosa sp. nov., adult: 5 — lateral view of anterior part of body (legs not shown); 6 — posterior view (pteromorphs not shown); 7 — leg I, without trochanter, right, antiaxial view; 8 — femur and genu of leg II, right, antiaxial view; 9 — trochanter, femur and genu of leg III, left, antiaxial view; 10 — leg IV, left, antiaxial view. Scale bar 100 Μm (5, 6), scale bar 20 Μm (7 – 10).

Tables

TABLE 1. Leg setation and solenidia of adult Macrogena hexasetosa sp. nov. (same data for Porallozetes badamdorji sp. nov.)

Leg	Trochanter	Femur	Genu	Tibia	Tarsus
I	v'	d, (l), bv'', v''	(l), v', σ	(l), (v), φ1, φ2	(ft), (tc), (it), (p), (u), (a), s, (pv), v'*, (pl), ɛ, ω1, ω2
II	v'	d, (l), bv'', v''	(l), v', σ	(l), (v), φ	(ft), (tc), (it), (p), (u), (a), s, (pv), ω1, ω2
III	l', v'	d, ev'	l', σ	l', (v), φ	(ft), (tc), (it), (p), (u), (a), s, (pv)
IV	v'	d, ev'	d, l'	l', (v), φ	ft'', (tc), (p), (u), (a), s, (pv)