Ceratorchestes (Paraceratorchestes) variabilis, Ermilov & Kalúz, 2012

Ermilov, S. G. & Kalúz, S., 2012, The Oribatid Mite Genus Ceratorchestes (Acari: Oribatida: Peloppiidae), Acarologia 52 (2), pp. 165-172 : 169-171

Ceratorchestes (Paraceratorchestes) variabilis n. sp.

( Figures 1-3 )

Diagnosis — Body size 481 – 813 × 431 – 664. Rostrum with deep indentation. Tubercle inserted near base of the indentation. Translamella present (rarely absent). Lamellar setae longer than rostral and interlamellar setae. Apodemal borders IV straight. Setae 3c inserted on pedotectum II. Setae pv” and s on leg IV modified.

Measurements — Body size varied considerable: body length 697 (holotype), 481 – 813 (mean 608; nine paratypes); notogaster width 514 (holotype), 431 – 664 (mean 521; nine paratypes).

Integument — Body color light brown to brown. Body surface smooth.

Prodorsum — ( Figure 1A, C ; Figure 2 A-C). Rostrum with deep indentation. Width of indentation variable; tubercle (tb) inserted near base of indentation. Lamellae longer than half the length of prodorsum, slightly converging. Translamella thin, mostly clearly visible, sometimes poorly visible, rarely absent. Rostral (ro, 61 – 82), lamellar (le, 82 – 123) and interlamellar (in, 73 – 110) setae setiform, barbed. Sensilli (ss, 147 – 172) setiform, ciliate.

Notogaster — ( Figure 1A, C ). Anterior margin medially convex. Dorsophragmata (D) present, small, but sometimes indistinct. Pleurophragmata (P) always distinct. Alveoli of setae c poorly visible. Nine pairs of notogastral setae long (h 1, p 1 - p 3 73 – 94, others 110 – 139) setiform, barbed. Opisthonotal gland openings (gla) small, located antero-laterally to notogastral setae h 3. Lyrifissures ia not visible, im located medially to gl a.

Lateral part of body — ( Figure 1A, C ). Pedotecta I, II (Pt I, Pt II) and tutoria (tu) well developed, morphology typical for genus. Large lateral tooth (t) present on each side of the prodorsum. Exobothridial setae (ex, 49 – 57) setiform, straight, barbed. Thin, sclerotized line present between each bothridium and acetabulum IV. Lyrifissures ih, ip and ips short, distinct.

Gnathosoma — ( Figure 2 D-F). Proportions of the subcapitulum variable: longer or shorter than width (114 – 176 × 123 – 164). Hypostomal setae setiform, slightly barbed; h (28 – 36) little shorter than m (32 – 41) and a (36 – 41). Adoral setae and their alveoli absent. Palp 94 – 98, with setation 0- 2-1-3-9(+1ω). Solenidion setiform, not connected with acm. Chelicera 155-164. Fixed and movable digits smooth, only one distal tooth developed on each digit. Cheliceral setae long, setiform, barbed; cha (28 – 32) longer, than chb (20 – 28). Trägårdh’s organ (Tg) distinct.

Epimeral region — ( Figure 1B ). Epimeral borders IV straight, connected to lateral sides of genital plates. Sternal longitudinal border present. Epimeral setae setiform, slightly or strongly barbed, differs in length: 1a, 2a, 3a, 4a -4e 16 – 24; 1b 41 – 106; 1c 41 – 114; 3b 24 – 28; 3c 32 – 53; 4d 28 – 32. Setae 3c inserted on pedotecta II.

Anogenital region — ( Figure 1B ; Figure 2G, H ). Six pairs of genital (g 1 - g 6, 16 – 24), one pair of aggenital (ag, 24 – 32), two pairs of anal (an 1, an 2, 20 – 41) and three pairs of adanal (ad 1 45 – 61, ad 2, ad 3, 32 – 45) setae present; setae setiform, slightly barbed. Size of genital plates variable; in many specimens smaller than anal plates, rarely similar in size. Asymmetric number of genital setae on genital plates is presented in two specimens (six on one plate, and seven on another plate). Lyrifissures iad paranal.

Legs — ( Figure 3 A-D). Median claw slightly thicker than lateral claws. Formulae of leg setation and solenidia: I (1-5-3-4-20) [1-2-2], II (1-4-3-4-15) [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 mostly setiform, barbed. Some setae on tarsi IV modified: pv” thick, weakly dilated mediodistally with dense cilia unilaterally; s thick, setiform, with dense cilia unilaterally. On tarsi I setae ft” short, inserted near to solenidion ω 1. Famulus setiform, straight, dilated distally, blunt-ended, inserted anterior to solenidion ω 2. Solenidia ω 1, ω 2 on tarsi II and σ on genua III rod-like, blunt-ended. Other solenidia setiform. Solenidia ’ 1 and ’ 2 on tibiae I inserted close to each other.

Type deposition — The holotype is deposited in the collection of the Zoological Institute of the Russian Academy of Sciences , St. Petersburg, Russia; Roman letters refer to normal setae (e to famulus), Greek letters to solenidia. Single prime (ʹ) marks setae on anterior and double prime (ʺ) setae on posterior side of the given leg segment. Parentheses refer to a pair of setae .

four paratypes are deposited in the collection of the Siberian Zoological Museum , Novosibirsk, Russia ; five paratypes are in the personal collection of the first author.

Etymology — The specific name " variabilis " refers to the strong variability of morphological characters (sizes of body and genital plates; form of rostrum; proportions of subcapitulum; presence or absence of translamella and epimeral border IV).

Remarks — Ceratorchestes (Paraceratorchestes) variabilis n. sp. can be distinguished from all known species of the genus Ceratorchestes by the key which is presented below.

Figures

FIGURE 1: Ceratorchestes (Paraceratorchestes) variabilis n. sp.: A – dorsal view, legs not shown; B – ventral view, legs and palps not shown; C – lateral view, legs, gnathosoma, apodemes, epimeral and anogenital setae not shown. Scale bars 200 µm.

FIGURE 2: Ceratorchestes (Paraceratorchestes) variabilis n. sp.: A – rostrum; B – rostrum; C – sensillus; D – subcapitulum, right half; E – palp; F – chelicera; G – genital plate, left; H – anal plate, left. Scale bars (A+D, F+H) 50 µm, scale bar (E) 20 µm.

FIGURE 3: Ceratorchestes (Paraceratorchestes) variabilis n. sp.: A – leg I, left, antiaxial view; B – leg II, left, antiaxial view; C – leg III, right, antiaxial view; D – leg IV, right, antiaxial view. Scale bars 50 µm.