Arthrhoplophora adjacentis, Fuangarworn, Marut, 2011

Fuangarworn, Marut, 2011, Two new species of protoplophorid mites (Acari: Oribatida: Protoplophoridae) from Thailand, Zootaxa 2732, pp. 59-67 : 60-63

Arthrhoplophora adjacentis sp. nov.

( Figs. 1–2 )

Diagnosis. Medium-size protoplophorids; strong neotrichy on pygidium, pleuraspis and anoadanal plates; rostral setae long, ciliated and situated adjacently to each others; eight pairs of genital setae; leg I bidactyl; legs II–IV hetero-tridactyl.

Female. Measurements of holotype: prodorsal length 162, width 117, and height 77; notogastral length 225, width 212, and height 170. Color light brown.

Prodorsum ( Figs. 1 A & B). Rostrum broadly rounded. Lateral carina distinct, extending from area above bothridia to anterolateral margin of rostrum. Sensilli (ss, 112–125) with barbs increasing in length from proximal to distal part ( Fig. 1 C). Interlamellar setae (in, 62), lamellar setae (le, 87), and rostral setae (ro, 112) thickened and densely ciliated; distance between base of pairs in -in (88)> le -le (60). Setal pair ro located close together on central region of prodorsum, distance between their bases 7.5. Anterior exobothridial setae (exa, 50) barbed, longer and thicker than posterior exobothridial setae (exp, 20), latter only slighty barbed. Setae exa usually directed vertically, exp directed horizontally. Surface of prodorsum smooth, with five clusters of muscle sigilla: dorso-median unpaired with eight to 10 sigilla; dorso-lateral pair with four or five sigilla anterolateral to setae le; and lateral pair with eight to 10 sigilla anterior to setae exp.

Notogaster ( Figs. 1 A & D). Surface of pronotaspis smooth, but with pronounced internal muscle sigilla anterior to line L; setal row c (c1, c2, c3, cp) not discernable, only their alveoli present; surface behind line L smooth. Pygidium with strong neotrichy of setal rows e and f, forming two transverse rows of long and ciliated setae; about 20 setae in row e (ca. 137–150) and 25 in row f (ca. 125); three pairs of setae h (150) and one pair of setae ps present on venter. Pleuraspis with four or five pairs of setae ps (112.5), and partly covered by lateral margins of pronotaspis.

Gnathosoma. Subcapitulum ( Fig. 1 E) with four pairs of thickened and barbed setae (h, m1, m2, and a); surface of mentum smooth, but with strong internal muscle sigilla. Lateral lips with three pairs of barbed adoral setae (or1- 3) of which or2 longest. Supracoxal setae (ep) short and rodlike. Chelicerae ( Fig. 1 F) chelate-dentate, digits with five or six teeth. Setae cha long and barbed; setae chb shorter, smooth and deeply split. Palpi ( Fig. 1 H) five-segmented; trochanters without setae; femora with two barbed setae; genua with one barbed seta; tibiae with three barbed setae; tarsi with thin solenidion ω, three thickened eupathidia (ul’, ul”, sul), and 10 barbed setae.

Coxisternal region ( Fig. 1 D). Epimeral plates distinctly sclerotized. All epimeral setae barbed and subequal, setation 3-2-2-5.

Anogenital region ( Figs. 1 D & I). Genitoaggenital plates subrectangular; with posterior extension covering anterior margins of anoadanal plate; surface finely striated; muscle sigilla present; with eight pairs of simple setae: six setae along inner margin, two setae inserted anterolaterally, all subequal in length. Three pairs of genital papillae present, slightly decreasing in size from anterior to posterior pair. Anoadanal plates subrectangular, longer than genitoaggenital plates; surface smooth with anterolateral extension membranes ( Fig. 1 I); strongly neotrichous: anteriorly with six to eight simple setae (37.5) and posteromedially with numerous (56–59 setae) long, ciliated setae (87.5–100).

Legs ( Fig. 2 ). Leg I hetero-bidactyl, legs II–IV hetero-tridactyl, all claws smooth. Claws large: those on pretarsi I–II subequal in length to respective tarsal segments, those on pretarsi III–IV longer than segments. Legs I–IV setation (trochanter to tarsus, famulus included): I (0- 5 -5-5-20); II (1-6-5-6-17); III (2-3-4-4-14); IV (2-3-4-4-13); formula of solenidia (genu to tarsus): I (0-1-3); II (0-1-2); III (0-1-0); IV (0-1-0). Tarsus I with thick and curved solenidion ω 1; solenidion ω 3 subequal in length to ω 1 but more slender; solenidion ω 2 situated on ventral side; famulus (ε) short and thin with pointed tip. Solenidion ϕ1 on tibia I very long. Setae on legs usually long, thickened and conspicuously barbed.

Males and Immatures. Unknown.

Etymology. This species is named after the unique arrangement of rostral setae which are adjacent ( adjacentis: Latin , adjacent).

Material examined. Holotype female (in ethanol, CUMZ-AC-2010.40), Thailand: Kaeng Krachan District, Petchaburi Province (12˚53’15”N, 99˚ 21’57”E), from leaf-litter of primary dry evergreen forest, 14 January 2004, coll. Sonthaya Jampanin (Jampanin & Gajaseni 2004). Eight paratype females (two on slides, CUMZ-AC- 2010.41–42 and six in ethanol, CUMZ-AC-2010.43–48) with same data as holotype. Holotype and seven paratypes deposited in the Acarology collection of Chulalongkorn University Museum of Natural History, Bangkok, Thailand. One paratype deposited in The Hungarian Natural History Museum, Budapest.

Remarks. Arthrhoplophora adjacentis sp. nov. represents the second oriental species, yet is most similar to the first oriental species from Java, A. paradoxa Berlese, 1910 , in having long ciliated setae on the prodorsum and hetero-tridactylous pretarsi II–IV. The position of the rostral setae of A. adjacentis sp. nov., however, is different from those of A. paradoxa in that they originate close together on the central region of prodorsum while those of A. paradoxa arise distant from each other and on the distal portion of the prodorsum. In addition, pretarsi I of A. adjacentis sp. nov. are bidactyl while those of A. paradoxa are tridactyl.

In his review of the family Protoplophoridae, Niedbała (2004) synonymized A. berlesei Mahunka, 1977 with A. vulpes Berlese, 1916 based only on published data by Mahunka (1977, 1994), and recognized two species in the genus Arthrhoplophora — A. paradoxa (described from Java) and A. vulpes (from Somalia). Subías (2004, 2010), in his world catalogue of Oribatida, accepted this taxonomic decision and further added A. zachvatkini ( Shereef, 1978) —from Neoprototritia , apparently following the generic synonymy made by Balogh and Balogh (1992) —to the genus Arthrhoplophora . However, without the study of type materials, these justifications seem to be premature and further detailed study of the type specimens is necessary. The present paper follows the generic classification of Niedbała (2004) but treats A. berlesei as a species inquirendae (following Balogh & Balogh 2002). It is not included in the identification key below

Figures

FIGURE 1. Arthrhoplophora adjacentis sp. nov., female. (A) Lateral view, legs and gnathosoma are removed; (B) prodorsum, dorsal view; (C) sensillus and bothridium, not in scale; (D) ventral view, legs and proterosoma are only partly drawn, setae on pygidium, plueraspis and anoadanal plates are represented only by their alveoli (black circles); (E) subcapitulum (palps partly drawn); (F) chelicera; (H) palp, abaxial aspect; (I) anoadanal plates, most setae are indicated only by alveoli.

FIGURE 2. Arthrhoplophora adjacentis sp. nov., female. (A – D) Legs I – IV, respectively, all in antiaxial aspect.