Scapheremaeus luxtoni, Ermilov, Sergey G. & Minor, Maria A., 2015

Ermilov, Sergey G. & Minor, Maria A., 2015, The genus Scapheremaeus (Acari, Oribatida, Cymbaeremaeidae) in the oribatid mite fauna of New Zealand, with description of two new species, ZooKeys 508, pp. 69-83 : 71-75

Taxon classification Animalia Oribatida Cymbaeremaeidae

Scapheremaeus luxtoni sp. n. Figs 23-25, 26-35, 36-42, 43-47

Diagnosis.

Body size: 381-415 × 199-232. Centro-dorsal part of notogaster areolate. Dorso-lateral parts of notogaster and ventral plate tuberculate. Costulae and transcostula strong. Rostral setae thin, straight. Lamellar setae minute. Bothridial setae globular. Humeral processes small, rounded. Circumdorsal scissure present. Ten pairs of short, simple notogastral setae. Palp femora with two setae. Six pairs of genital setae. Lyrifissures iad longitudinally oriented. Tridactylous.

Description.

Measurements. Body length: 381 (holotype: male), 381-415 (three paratypes: all females); notogaster width: 199 (holotype), 232 (same for three paratypes).

Integument. Body color light yellow-brownish. Anterior part of prodorsum and centro-dorsal part of notogaster with areolate sculpturing. Dorso-lateral parts of notogaster and ventral plate with elongated ridge-like tubercles.

Prodorsum. Rostrum broadly rounded. Costulae (cos) distinct, forming slightly visible X-structure, terminated by large tubercles, which connected by thick transcostula (tcos). Rostral setae (6) thin, straight, inserted on transverse fold. Lamellar setae (4) minute, inserted nearer to rostral setae than to bothridia. Interlamellar and exobothridial setae and their alveoli absent. Bothridial setae (22-24) globular, pigmented, with short stalk (6) and longer (16-18) head, having longitudinal ridges.

Notogaster flattened. Anterior margin straight. Lenticulus distinct. Humeral processes (Hp) slightly developed, tubercle-like in dorsal view and rounded in lateral view. Centrodorsal zone with longitudinal elongate hump-like structure. Circumdorsal scissure (f) present. Ten pairs of simple notogastral setae, located on small tubercles. Centro-dorsal part with two pairs of setae (lm, lm), both inserted near to scissure. All lyrifissures (except ia) well visible. Opisthonotal gland openings located medially to ih.

Gnathosoma. Subcapitulum longer than wide (82-90 × 61-69). Subcapitular setae thin, smooth; a and adoral setae (all 10) longer than m and h (both 6-8). Setae a slightly thicker than other. Palps (53-61) with setation 0 –2–1–3– 9(+ω). Solenidion free, not attached to eupathidium. Chelicerae (82-90) with two simple, barbed setae (both 16-20). Trägårdh’s organ long, tapered.

Epimeral and lateral podosomal regions. Anterior tectum slightly developed. Pedotecta I of medium size, concave in dorsal view and scale-like in lateral view. Pedotecta II elongated, bifurcate distally in ventral view and broadly triangular in lateral view. Apodemes 1, 2, sejugal and 3 distinctly developed. Epimeral setal formula 3 –1–2– 2. Epimeral setae short (4), thin, smooth. Discidia roundly triangular.

Anogenital region. Six pairs of genital, one pair of aggenital, two pairs of anal and three pairs of adanal setae similar in length (4), thin, smooth, inserted on small tubercles. Lyrifissures iad longitudinally oriented. Ovipositor elongated (52-56 × 41-45), lobes (32-36) longer than length of distal section (beyond middle fold; 20). Each of three lobes with four straight, smooth setae, ψ 1 ≈ τ 1 (24-28) longer than ψ 2 ≈ τa ≈ τb ≈ τc (16). Coronal setae and their alveoli absent.

Legs. Tridactylous. Porose areas slightly visible, oval. Formulas of leg setation and solenidia as in Scapheremaeus gibbus sp. n.; homology of setae and solenidia as indicated in Table 1. Famuli short, slightly dilated distally. Solenidia (except simple ω on tarsi and φ 1, and thin σ on genua I) dilated distally. Setae l on tibiae I setiform, not modified.

Material examined.

Holotype (male) and three paratypes (all females): New Zealand, South Island, Central Otago, Pisa Range, 44°52'19"S, 169°10'30"E, 1880 m a.s.l., in soil and debris under Dracophyllum muscoides cushion and in the soil outside of Dracophyllum muscoides cushion, 18 February 2014, collected by M. Minor.

Type deposition.

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

Etymology.

The specific name is dedicated to the well-known acarologist Malcolm Luxton, for his extensive contributions to our knowledge of New Zealand oribatid mite fauna.

Remarks.

The new species is similar to Scapheremaeus yamashitai Aoki, 1970 from Japan (see Aoki 1970; Fujikawa 2002) in having circumdorsal furrow, tridactylous legs, costulae and transcostula, ten pairs of minute notogastral setae and areolate centrodorsal region of notogaster. However, it differs from the latter by the presence of thin notogastral setae (versus thickened), straight rostral setae (versus curved medially), short and dilated distally leg solenidia φ 2 (versus long and simple) and slightly developed humeral processes (versus well developed).

Also, in having circumdorsal furrow, tridactylous legs, costulae, minute notogastral setae, straight rostral setae and areolate centrodorsal region of notogaster, Scapheremaeus luxtoni sp. n. is similar to Scapheremaeus zephyrus Colloff, 2010 from Australia (see Colloff 2010) and New Zealand (our data). However, it differs from the latter by the presence of large tubercle-like distal parts of costulae (versus small), strong transcostula (versus absent), ten pairs of thin notogastral setae (versus nine pairs and thickened) and three pairs of adanal setae (versus two pairs).