Scapheremaeus gibbus, 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 : 70-71

Taxon classification Animalia Oribatida Cymbaeremaeidae

Scapheremaeus gibbus sp. n. Figs 1-3, 4-12, 13-17, 18-22

Diagnosis.

Body size: 270-307 × 131-147. Body surface areolate-reticulate. Costulae reduced, terminated by tubercles. Transcostula not developed. Rostral setae thin, directed medially. Lamellar setae minute. Bothridial setae globular. Humeral processes and circumdorsal scissure absent. Thirteen pairs of short, simple notogastral setae. Anterior tectum of ventral plate strongly developed. Palp femora with one seta. Five pairs of genital setae. Lyrifissures iad in transverse position. Monodactylous. Femora I and II with extremely large ventral expansions.

Description.

Measurements. Body length: 299 (holotype: female), 270-307 (seven paratypes: four females and three males); notogaster width: 147 (holotype), 143-151 (seven paratypes).

Integument. Body color light yellow-brownish. Body surface with areolate-reticulate sculpturing.

Prodorsum. Rostrum broadly rounded. Costulae reduced, terminated by tubercles, bearing lamellar setae. Transcostula absent. Rostral setae (ro, 10) thin, smooth, directed medially, inserted on transverse fold. Lamellar setae minute (le, 4), thin, straight, inserted nearer to bothridia than rostral setae. Interlamellar and exobothridial setae and their alveoli absent. Bothridial setae (ss, 22-24) globular, pigmented, with short stalk (6-8) and longer (16) head, having longitudinal ridges.

Notogaster. Normal in form, not flattened. Anterior margin slightly convex medially. Lenticulus (len) distinct. Humeral regions without processes. Centrodorsal zone forming longitudinal elongate hump-like structure. Circumdorsal scissure absent. Thirteen pairs of simple notogastral setae, located on small tubercles. Centro-dorsal part with four pairs of setae (da, dm, lm, dp). All lyrifissures (im, ip, ih, ips; except ia) well visible. Opisthonotal gland openings (gla) located posteriorly to im.

Gnathosoma. Subcapitulum longer than wide (53-57 × 32-36). Subcapitular setae thin, smooth; a and m (both 10) longer than h (6) and adoral setae (or1, or2, 4-6). Setae a slightly thicker than other. Palps (41-45) with setation 0 –1–1–3– 9(+ω). Solenidion free, not attached to eupathidium (acm). Chelicerae (53-57) with two simple, barbed setae; cha (16-18) longer than chb (12). Trägårdh’s organ long, tapered.

Epimeral and lateral podosomal regions. Anterior tectum strongly developed. Pedotecta I large, 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 (dis) roundly triangular.

Anogenital region. Five pairs of genital (g1-g5), one pair of aggenital (ag), two pairs of anal (an1,an2) and two pairs of adanal (ad1, ad2) setae similar in length (4), thin, smooth, inserted on small tubercles. Lyrifissures iad in transverse position. Ovipositor elongated (68-77 × 32-36), lobes (36-41) longer than length of distal section (beyond middle fold; 32-36). Each of three lobes with four straight, smooth setae, ψ 1 ≈ τ 1 (20) longer than ψ 2 ≈ τa ≈ τb ≈ τc (8-10). Coronal setae and their alveoli absent.

Legs. Monodactylous. Femora I and II with extremely large ventral expansions. Porose areas (p.a) slightly visible, oval. Formulas of leg setation and solenidia: I (0 –4–2–4– 16) [1 –2– 2], II (0 –4–2–3– 15) [1 –1– 1], III (1 –2–1–3– 14) [1 –1– 0], IV (0 –2–1–3– 12) [1 –1– 0]; homology of setae and solenidia as indicated in Table 1. Famuli (ε) short, slightly dilated distally. Solenidia simple, σ on genua IV minute. Setae l on tibiae I setiform, not modified.

Material examined.

Holotype (female) and seven paratypes (four females and three males): New Zealand, South Island, Central Otago, Old Man’s Range, 45°18'58"S, 169°11'45"E, 1646 m a.s.l., in soil and debris under Dracophyllum muscoides cushion, 17 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; three paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia.

Etymology.

The specific name gibbus refers to the clearly convex centrodorsal notogastral region, forming longitudinal elongate hump-like structure.

Remarks.

The new species is most similar to Scapheremaeus humeratus Balogh & Mahunka, 1967 from Congo (see Balogh and Mahunka 1967) in having small body size, monodactylous legs, simple notogastral setae, areolate body surface, and absence of circumdorsal furrow. However, it differs from the latter by the presence of 13 pairs of notogastral setae (versus 11), globular bothridial setae (versus fusiform), five pairs of genital setae (versus six), two pairs of adanal setae (versus three), transverse position of adanal lyrifissures (versus longitudinal) and absence of humeral processes (versus well developed).