Graptoppia (Stenoppia) royi, Ermilov, 2019

Ermilov, Sergey G., 2019, Oribatid mites (Acari: Oribatida) phoretic on passalid beetles (Coleoptera: Passalidae), with description of a new species from Indonesia, Ecologica Montenegrina 22, pp. 90-96 : 91-95

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, h 1 – h 3, p 1 – p 3, 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 (or 1, or 2, 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 (g 1 – g 4, 6), one pair of aggenital (ag, 8), two pairs of anal (an 1, an 2, 8) and three pairs of adanal (ad 1 – ad 3, 8) setae setiform, slightly barbed. Adanal lyrifissures (iad) located close and parallel to anal plates.

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 ω 1. Solenidia ω 1 on tarsi I, ω 1 and ω 2 on tarsi II, φ on tibiae I–III and σ on genua III bacilliform, ω 2 on tarsi I and φ 2 on tibiae I slightly thickened, slightly blunt-ended, other solenidia setiform.

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 specimens are in ethanol with a drop of glycerol.

Etymology. The species name is dedicated to the well-known acarologist, Prof. Dr. Roy A. Norton (State University of New York, Syracuse, U.S.A.) for his extensive contributions to our knowledge of mites.

Differential diagnosis. Graptoppia (Stenoppia) royi sp. nov. is morphologically most similar to Graptoppia (Stenoppia) italica ( Bernini, 1973) from the Mediterranean in having transcostula, rounded rostrum, ciliate bothridial setae, short exobothridial setae, rounded anterior margin of notogaster and barbed notogastral setae, but differs from the latter by the smaller body size (164–176 × 73–90 versus 207 × 105), the presence of thin transcostula and the absence of costulae (versus costulae and transcostulae thick, forming trapezoid structure).

General remarks

As it was noted earlier ( Norton 1980; Ermilov & Frolov 2019a), beetles of the family Passalidae are one of the representatives of Coleoptera which are actively used by oribatid mites for phoresy.

Norton (1980) presented data on unidentified Mesoplophora , Malaconothrus , Oppia , Protoribates , Scheloribates and Metaleius spp. phoretic on 19 identified and one unidentified species of Passalidae ( Passalus interruptus , P. interstitialis , P. morio , P. punctiger , Passalus sp. , Popilius disjunctus , Proculus goryi , Verres longicornis , Ptichopus angulatus , Labienus compergus , L. inaequalis , L. ptox , Macrolinus batesi , M. latipennis , Aceraius grandis , A. helferi , A. laevicollis , A. pilifer , Erionomus planiceps , E. platypleura ), which were collected from the different regions of the world. Later, Niedbała (1985, 2000) identified many Mesoplophora spp. from these materials, having recorded: Mesoplophora (Mesoplophora) permodica Niedbała, 1985 phoretic on Popilius disjunctus ( U.S.A.); Mesoplophora (Parplophora) flavida Niedbała, 1985 on Aceraius helferi ( Thailand), A. laevicollis ( Indonesia), A. pilifer ( Philippines), and Macrolinus latipennis ( Indonesia); M. (P.) polita Niedbała, 1985 on Labienus inaequalis , and L. ptox (both New Guinea); M. (P.) subtilis Niedbała, 1981 on Aceraius laevicollis ( Indonesia), Labienus inaequalis , L. ptox (both New Guinea), Passalus interruptus ( Surinam), P. interstitialis ( Honduras), P. punctiger ( Brazil, Honduras), and P. sp. ( Panama).

Franklin & Woas (1992) described Neoamerioppia phoretica ( Franklin & Woas, 1992) phoretic on unknown passalid beetle from Brazil.

Corpuz-Raros (1992) noted some species of oribatid mites on unknown passalids from the Philippines, however, these mites were located loosely on beetles (pers. com. Dr. L.A. Corpuz-Raros), therefore, it is premature to consider them active phoretic species.

Ermilov & Frolov (2019) registered five species ( Mesoplophora (Parplophora) flavida , M. (P.) polita, Graptoppia (Stenoppia) luisi Ermilov & Frolov, 2009 , Ramusella (Sabahoppia) blattarum ( Oudemans, 1911) , and Perscheloribates kontumensis Ermilov & Frolov, 2009 ) phoretic on A. grandis from Vietnam.

Hence, 19 identified beetle species of Passalidae , which were used by oribatid mites as hosts for active phoresy, are known; and only nine identified oribatid species (and also some not identified species) phoretic on these passalids are registered.

Thus, the phoresy of oribatids on beetles (first of all on Passalidae ) remains a poorly studied aspect of acarology, and requires further detailed faunistic and ecological researches for understanding of relationship between Oribatida and Insecta.

Figures

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.

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).