Ecologica Montenegrina 22: 90-96 (2019) This journal is available online at: www.biotaxa.org/em https://zoobank.org/urn:lsid:zoobank.org:pub:D1A0E6C6-D3EA-49AB-A7D7-34EF1EA5D953 Oribatid mites (Acari: Oribatida) phoretic on passalid beetles (Coleoptera: Passalidae), with description of a new species from Indonesia SERGEY G. ERMILOV Tyumen State University, Tyumen, Russia. E-mail: [email protected] Received 13 July 2019 │ Accepted by V. Pešić: 1 August 2019 │ Published online 25 August 2019. Abstract A new species of oribatid mites (Oribatida) phoretic on the beetle, Macrolinus batesi (Coleoptera, Passalidae) is described from Sumatra, Indonesia. Graptoppia (Stenoppia) royi sp. nov. (Oppiidae) differs from G. (S.) italica by the smaller body size, the presence of thin transcostula and the absence of costulae. Data on oribatids phoretic on passalid beetles are summarized; nine identified oribatid species (from 19 beetle species) are listed. Key words: phoresy, Graptoppia (Stenoppia), Insecta, systematics, morphology, Sumatra. Introduction The phoretic association of some groups of mites (Acari) with beetles (Insecta, Coleoptera) is widely known, however, the phoresy of oribatid mites (Oribatida) remains poorly studied, and therefore, each new case of their phoresy is important and interesting to science. Some oribatid species have morphological adaptations for attachment to the beetles (e.g., phoretic ptyctimous mites clasps the body setae of hosts between the rostrum of the aspis and the anterior portion of the genital plates; some Oppiidae and Scheloribatidae have modified leg claws allowing mites to be attached to the hosts) (see Norton 1980; Ermilov & Frolov 2019a,b). The majority of oribatid species have no morphological adaptations for phoresy, however the hosts have many unexposed body places on the ventral side (e.g., various grooves, ditches, poles) and under elytra, where a phoretic mite could ‗hide‘ and held on any surface that has some irregularity using the force of the leg claws (Ermilov & Frolov 2019a). During the taxonomic identification of phoretic oribatids1 on the passalid beetle, Macrolinus batesi (Passalidae) from Indonesia, I found one new species belonging to the genus Graptoppia Balogh, 1983, the subgenus Stenoppia Balogh, 1983 (family Oppiidae). This subgenus comprises seven species, which are distributed in the Ethiopian, Neotropical and Oriental regions, as well as the Mediterranean and Japan (Ermilov & Frolov 2019a). The main diagnostic characters of Graptoppia (Stenoppia) were summarized by Balogh (1983), Subías & Balogh (1989), and Balogh & Balogh (1992). An identification key to known 1 Specimens were kindly sent me by Prof. Dr. Roy A. Norton (State University of New York, Syracuse, U.S.A.) from the personal collection. Ecologica Montenegrina, 22, 2019, 90-96 ERMILOV species is presented by Ermilov & Frolov (2019a). The main goal of this paper is to describe and illustrate the new species based on adults under the name Graptoppia (Stenoppia) royi sp. nov., and to summarize data on phoresy of Oribatida on Passalidae. Material and methods Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. All body measurements are presented in micrometers. Drawings were made with a camera lucida using a Leica transmission light microscope ―Leica DM 2500‖. Morphological terminology used in this paper follows that of F. Grandjean: see Travé & Vachon (1975) for references, Norton (1977) for leg setal nomenclature, and Norton & Behan–Pelletier (2009), for overview. Systematics Family Oppiidae Subfamily Multioppiinae Genus Graptoppia Balogh, 1983 Subgenus Graptoppia (Stenoppia) Balogh, 1983 Graptoppia (Stenoppia) royi sp. nov. (Figs 1, 2) Diagnosis. Body size: 164–176 × 73–90. Rostrum rounded. Costulae absent. Transcostula poorly developed. Rostral, lamellar and interlamellar setae setiform, slightly barbed; le located on transcostula. Bothridial setae long, with unilaterally dilated, ciliate, rounded distally head. Anterior notogastral margin rounded. Notogastral setae c minute, needle-form, other setae of medium size, setiform, slightly barbed. Epimeral and anogenital setae setiform, slightly barbed. Epimeral border IV semi-oval. Description of adult. Measurements. Body length: 172 (holotype: female), 164–176 (13 paratypes: 10 females and 3 males); notogaster width: 73 (holotype), 73–90 (13 paratypes). No difference between females and males in body size. Integument (Fig. 1A). Body color light brownish. Body surface smooth, but region between transcostula and interlamellar setae microgranulate (diameter of granules less than 1), and lateral parts of body between bothridia and acetabula I–III sparsely tuberculate (diameter of tubercles up to 2). Prodorsum (Figs 1A, 1C). Rostrum rounded. Costulae absent. Transcostula (tcos) present, thin, poorly visible. Lateral semi-oval ridges not observed. Rostral (ro, 12–14), lamellar (le, 8–10) and interlamellar (in, 8–10) setae setiform, slightly barbed; le inserted on transcostula. Exobothridial setae (ex, 4) setiform, thin, smooth. Bothridial setae (bs, 30–32) with long stalk and shorter, unilaterally dilated and ciliated, rounded distally head (with 8-9 cilia). Interbothridial region with two pairs of clear muscle sigillae. Interbothridial tubercles absent. Postbothridial tubercles slightly developed. Longitudinal rows of muscle sigillae anteriad to bothridia present. Notogaster (Figs 1A, 1C, 1D). Anterior margin rounded. Ten pairs of notogastral setae; c (4) needle- form, others (la, lm, lp, h1–h3, p1–p3, 12–14) setiform, slightly barbed. Opisthonotal gland openings (gla) and all lyrifissures (ia, im, ip, ih, ips) distinct. Gnathosoma (Figs 2A–2C). Subcapitulum longer than wide (36–41 × 28–32). Subcapitular setae (a, m, h, 10–12) setiform, slightly barbed. Adoral setae (or1, or2, 4) setiform, thin, smooth. Palps (28–32) with typical setation 0-2-1-3-9(+ω). Postpalpal setae (4) thorn-like, smooth. Chelicerae (36–41) with two setiform, barbed setae (cha, 10–12; chb, 6–8). Trägårdh‘s organ (Tg) of chelicerae narrowly triangular. Epimeral and lateral podosomal regions (Figs 1B, 1C). With typical epimeral setal formula 3-1-3-3. Setae setiform, slightly barbed; 3c (12) longer than 1b, 3b, 4a, 4b, 4c (8) and 1a, 1c, 2a, 3a (6–8). Discidia triangular, rounded distally. Epimeral border IV distinct, semi-oval. Anogenital region (Figs 1B–D). Four pairs of genital (g1–g4, 6), one pair of aggenital (ag, 8), two pairs of anal (an1, an2, 8) and three pairs of adanal (ad1–ad3, 8) setae setiform, slightly barbed. Adanal lyrifissures (iad) located close and parallel to anal plates. Ecologica Montenegrina, 22, 2019, 90-96 91 ORIBATID MITES PHORETIC ON PASSALID BEETLES FIGURE 1. Graptoppia (Stenoppia) royi sp. nov., adult: A — dorsal view (legs not shown); B — ventral view (gnathosoma and legs not shown); C — anterior part of body (gnathosoma and legs not shown), lateral view; D — posterior part of body, lateral view. Scale bar 50 μm. 92 ERMILOV FIGURE 2. Graptoppia (Stenoppia) royi sp. nov., adult: A — subcapitulum, ventral view; B — palp, right, antiaxial view; C — chelicera, right, antiaxial view; D — leg I, without trochanter, right, antiaxial view; E — femur and genu of leg II, left, dorsoantiaxial view; F — trochanter, femur and genu leg III, right, paraxial view; G — leg IV, left, antiaxial. Scale bar 10 μm (A; B; C; D–G). Ecologica Montenegrina, 22, 2019, 90-96 93 ORIBATID MITES PHORETIC ON PASSALID BEETLES Legs (Figs 1D–G). Claw on leg tarsi smooth. Porose area on femora and on trochanters III and IV not observed. Formulas of leg setation and solenidia: I (1-5-2-4-19) [1-2-2], II (1-5-2-4-16) [1-1-2], III (2-3- 1-3-15) [1-1-0], IV (1-2-2-3-12) [0-1-0]; homology of setae and solenidia indicated in Table 1. Setae p setiform on tarsi I, and very short, conical on tarsi II–IV. Famulus of tarsi I erect, blunt-ended, inserted posterior to solenidion ω1. Solenidia ω1 on tarsi I, ω1 and ω2 on tarsi II, φ on tibiae I–III and σ on genua III bacilliform, ω2 on tarsi I and φ2 on tibiae I slightly thickened, slightly blunt-ended, other solenidia setiform. TABLE 1. Leg setation and solenidia of adult Graptoppia (Stenoppia) royi sp. nov. Leg Tr Fe Ge Ti Ta (ft), (tc), (it), (p), (u), (a), s, (pv), v’, (pl), I v’ d, (l), bv”, v” (l), σ (l), (v), φ1, φ2 ɛ, ω1, ω2 II v’ d, (l), bv”, v” (l), σ (l), (v), φ (ft), (tc), (it), (p), (u), (a), s, (pv), l”, ω1, ω2 III l’, v’ d, l’, 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) Note: Tr, Fe, Ge, Ti, Ta – leg trochanter, femur, genu, tibia, tarsus, respectively. 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. Material examined. Holotype (female) and 13 paratypes (10 females and 3 males): Indonesia, Sumatra, Batang Makat Forest, in various ventral grooves on pro- and mesothorax (morphological adaptations for attachment are absent in mites) of passalid beetle, Macrolinus batesi Kuwert, 1898, [collection date is unknown] in the year of 1937 (Coll. C.T. & B.B. Brues). Type deposition. The holotype and two paratypes are deposited in the collection of the Smithsonian Institution, Museum of Natural History, Washington, D.C., U.S.A.; 11 paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. All type