Humerobates rostrolamellatus Grandjean, 1936

SchatzK, Heinrich, 2024, Some Ceratozetoidea species (Acari: Oribatida: Ceratozetidae, Humerobatidae) from the Galapagos Islands, Acarologia 64 (2), pp. 463-479 : 475

Humerobates rostrolamellatus Grandjean, 1936

Humerobates humeralis Sellnick 1928: p. 11 , fig. 13. Humerobates rostrolamellatus Grandjean 1936: p. 77 , fig. 8 b; Sellnick 1959: p. 124, fig. 5 a, b; Pérez-Íñigo 1993: p. 162, figs 61 a-c; Weigmann 2006: p. 396, figs 211 h, i. Porozetes sp. Schatz 1998: p. 387.

The species is frequently cited in distribution lists, including studies on arboricolous mites, especially on fruit trees (De Giosa and Barretto 2022), and is used as bioindicator of air pollution (e.g., André et al. 1984). However, few descriptions exist. The single specimen examined from Galapagos is morphologically consistent with the descriptions by Grandjean (1936) ; Pérez-Íñigo (1993) and Weigmann (2006). Additional morphological features based on the Galapagos specimen are presented here.

Body size — (female). 670 x 450.

Supplementary description — Color chestnut brown, surface smooth. Rostrum rounded and slightly protruding in dorsal aspect. Prolamella well visible, anterior tips of prolamellae forming small attenuating teeth laterally. Lamellar cusp short, broader than insertion of lamellar seta. Translamella narrow, continuous. Prodorsal setae setiform with very short bristles, rostral (ro, 130) and lamellar setae (le, 180) directed anteromediad, interlamellar setae longer in (,

200), inserting on anterior margin of notogaster, directed anterolaterad. Bothridial seta bs)(short, with small stem, head almost round (diameter 15–18), spoon-shaped. Tutorium long and small blade tu (, 150), laterally rounded and protruding, anterodistal edge rounded with small tip dorsally (Remark #3). Exobothridial seta long ex (, 60), with very short bristles, insertion posterolateral to bothridium, partially hidden under pedotectum I. Humeral porose area Ai small, oval (15 x 10), anterolateral to bothridium. Notogaster very broad, almost round, convex, anterior margin slightly projecting anteriad. Pteromorph well developed, movable, triangular, radially striated. Notogastral setae very short (6–10), attenuating, inserting in small indentations. Four pairs of oval porose areas, Aa very small and long (10–15 x 50). Postanal porose area small, elongate (Ap, ~10 x 110), hidden under posterior notogastral tectum. Length of epimeral, genital, aggenital, anal setae ~20–30. Epimeral setal formula 3–1–3–3. Setal formula of legs (trochanter to tarsus, famulus included, solenidia in parentheses): leg I 1–5– 3(1)–4(2)–20(2), leg II 1–5–3(1)–4(1)–15(2), leg III 2–3–1(1)–3(1)–15, leg IV 1–2–2–3(1)–12. Solenidion φ 1 on tibia I 200, σ on genu I 120. Two eggs, size 220 x 130, 180 x 80, shape oval.