Macrogena brevisensilla, Ermilov, Sergey G. & Minor, Maria A., 2015

Ermilov, Sergey G. & Minor, Maria A., 2015, The oribatid mite genus Macrogena (Acari, Oribatida, Ceratozetidae), with description of two new species from New Zealand, ZooKeys 506, pp. 13-26 : 15-16

Taxon classification Animalia Oribatida Ceratozetidae

Macrogena brevisensilla sp. n. Figs 1-4, 5-9, 10-13, 14-22

Diagnosis.

Body size: 315-332 × 182-199. Lamellar cusps without teeth. Translamella broad. Rostral setae dilated in medio-distal parts, ciliated. Lamellar and interlamellar setae long, thickened, densely barbed. Bothridial setae globular. Tutoria broadly triangular. Four pairs of notogastral porose areas present. Notogastral setae short, thin. Epimeral setae 1c thickened, barbed. Tridactylous.

Description.

Measurements. Body length: 332 (holotype: female), 315-332 (six paratypes: three females, three males); notogaster width: 182 (holotype), 182-199 (six paratypes).

Integument. Body color light brown to brown. Body surface punctate (visible under high magnification). Lamellae, epimeral region, pedotecta I and subcapitular mentum with striae.

Prodorsum. Anterior edge of medial ledge of rostrum slightly wavy, lateral incisions very narrow. Lamellae shorter than half of prodorsum. Lamellar cusps without teeth. Translamella straight, broad. Rostral setae (ro, 32-41) dilated in medio-distal parts, ciliated. Lamellar (le, 49-57) and interlamellar (in, 82-90) setae thickened, densely barbed. Lamellar setae sometimes slightly dilated medio-distally. Bothridial setae (ss, 22-26) globular, with short stalk (4-6) and longer, indistinctly barbed head (18-20). Tutoria (tu) broadly triangular distally. Exobothridial setae (ex, 4) thin, smooth.

Notogaster. Anterior margin convex medially. Pteromorphs broadly rounded laterally. Porose areas Am elongate oval. Dorsophragmata (D) of medium size. Four pairs of porose areas present, all rounded: Aa (8), A1, A2 and A3 (6). Notogastral setae thin, smooth, c (12) little longer than other nine pairs (6-8). Lyrifissures ia, im, ip, ih and ips distinct. Opisthonotal gland openings (gla) located posteriorly to im.

Gnathosoma. Subcapitulum longer than wide (86 × 61-65). Subcapitular setae h (4-6) thin, smooth; a (12-16) and m (18-20) setiform, slightly barbed. Adoral setae (or1, or2, 8-10) simple, densely barbed. Palps (53-61) with setation 0 –2–1–3– 9(+ω). Solenidion attached to eupathidium, both located on dorsal tubercle. Chelicerae (90-94) with two simple, barbed setae; cha (28-32) longer than chb (16-20). Trägårdh’s organ (Tg) long, tapered.

Epimeral and lateral podosomal regions. Pedotecta I (Pd I) large, concave in dorsal view. Pedotecta II (Pd II) of medium size, triangular, rounded distally in ventral view. All pedotecta scale-like in lateral view. Genal teeth (gt) elongate narrowly triangular. Apodemes 1, 2, sejugal and 3 distinctly developed. Epimeral setal formula 3 –1–2– 2. Epimeral setae 1c (10) thickened, barbed; other setae (4-6) thin, smooth. Custodia (cus) with long, pointed tips. Discidia (dis) triangular. Circumpedal carinae (cp) distinct.

Anogenital region. Genital (g1-g5, 4-6), aggenital (ag, 4-6), anal (an1, an2, 4-6) and adanal (ad1-ad3, 6-8) setae thin, smooth. Lyrifissures iad located close to anal aperture, in paraanal position. Ovipositor elongated (102-110 × 28), blades (45-49) shorter than length of distal section (beyond middle fold; 57-61). Each of three blades with four straight, smooth setae, ψ 1 ≈ τ 1 (32) longer than ψ 2 ≈ τa ≈ τb ≈ τc (14-16). Six coronal simple setae (k, 8) present.

Legs. Tridactylous. Medial claw thicker than two laterals; all indistinctly serrate dorsally. Genua I and II, and femora II with antero-ventral tooth (t). Formulae of leg setation and solenidia: I (1 –5–3–3– 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. Famulus (ε) short, blunted. Setae l’’ on tibiae and genua I, II thick.

Material examined.

Holotype (female) and six paratypes (three females and three males): New Zealand, South Island, Central Otago, The Remarkables, 45°3'38"S, 168°48'43"E, 1867 m a.s.l., in the soil and debris under Raoulia sp. cushion, 19 February 2014, collected by M. Minor.

Type deposition.

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

Etymology.

The specific name brevisensilla refers to the short bothridial setae (sensilla).

Remarks.

Macrogena brevisensilla sp. n. differs from all species of this genus by the tridactylous legs.

Wallwork (1966) considered monodactylous legs as the generic character of Macrogena . The new species has tridactylous legs, however, all other morphological traits correspond to the other species of this genus. Thus, we included Macrogena brevisensilla sp. n. in Macrogena , and included alternatively tridactylous legs in the revised generic diagnosis.