Pachylaelaps (Longipachylaelaps) brevipilis, Masan, Peter, Oezbek, Hasan Hueseyin & Fenďa, Peter, 2016

Masan, Peter, Oezbek, Hasan Hueseyin & Fenďa, Peter, 2016, Two new species of Pachylaelaps Berlese, 1888 from the Iberian Peninsula, with a key to European species (Acari, Gamasida, Pachylaelapidae), ZooKeys 603, pp. 71-95 : 78-85

Taxon classification Animalia Mesostigmata Pachylaelapidae

Pachylaelaps (Longipachylaelaps) brevipilis sp. n. Figures 20-21, 22-26, 27-34, 35-38, 39-42

Specimens examined.

Holotype female: North Portugal, Serra da Labruja Mts., San Bento da Porta Aberta Village, Viana do Castelo Cadaster, non-native eucalyptus forest ( Eucalyptus globulus ), humid leaf litter and soil detritus, altitude 260 m, 41°56'02,3"N, 08°37'49,9"W, 10 May 2008, coll. P. Fenďa. Paratypes: 45 females and 14 males, with the same data as in holotype. The holotype and paratypes are deposited at the Institute of Zoology, Slovak Academy of Sciences, Bratislava; six paratypes (three females and three males) are deposited at the Acarology Laboratory of Erzincan University, Turkey.

Diagnosis.

Soft integument with decreased number of 13 pairs of setae in female and ten setal pairs in male. Dorsal setae J5 well developed, slightly longer than setae J4. Prestigmatic section of peritreme long, with anterior tip reaching dorsal surface close to setae z1. Dorsal setae relatively short (longest setae not exceeding 35 μm in length), with their tips not reaching bases of following setae. Cheliceral digits unidentate; pilus dentilis conspicuously enlarged (in female) or vestigial (in male). Male palptibia with two petal-like projections, shorter than cross-sectional radius of palptibia. Terminal part of male tarsus II with only one spur-like distal seta (pl1). Sperm induction system with tubular components: tubes relatively shorter, with club-shaped apical section, straight or variously curved; basal part not markedly expanded, thin, associated with inner middle surface of coxa IV.

Description.

Female. Dorsal idiosoma (Figure 20). Dorsal shield 510-565 μm long and 285-315 μm wide, elongated and suboval (length/width 1.75-1.95), delicately and evenly reticulated on surface, and bearing 30 pairs of dorsal setae. Dorsal setae uniform, smooth and needle-shaped, subequal in length, relatively short, and mostly with tips not reaching bases of following setae; setae z1 shortest and setae j3, j4, z4, r2, and r3 longest (46-51 μm). Length and spacing of some selected dorsal shield setae as follows: j1 24-29 μm, j5 22-26 μm, j5-j5 53-64 μm, j5-z5 31-41 μm, J1 25-29 μm, J1-J2 44-54 μm, J2 26-31 μm, J2-J2 98-114 μm, J2-J3 88-97 μm, J3 24-30 μm, J3-J4 63-85 μm, J4 22-30 μm, and J5 24-31 μm; setae J4/J5 0.87-0.96. Dorsolateral soft integument with five pairs of marginal setae (r6, R1, R4, R6, R7). One pair of posterolateral poroid structures (gdS4) slit-like, placed between setae S4 and S5.

Ventral idiosoma (Figure 21). Sternal shield 190-205 μm long, usually longer than genitiventral shield (length of sternal shield/length of genitiventral shield 0.98-1.12), with concave anterior margin and two small corners close to bases of sternal setae st1. Genitiventral shield slightly longer than wide (length 175-202 μm, width 155-185 μm, length/width 1.05-1.17). Anal shield subtriangular, 70-85 μm long and 95-115 μm wide (length/width 0.65-0.80); anus with circum-anal setae situated close to posterior margin of shield. Peritremes well developed, with anterior tip reaching dorsal surface between setae z1 and z2. Peritrematal shields with weak longitudinal sculp tural lines, other ventral shields distinctly and evenly reticulated on surface. Metapodal platelets minuscule, free on soft integument, and situated at level of setae JV1. Ventral soft integument with eight pairs of ventral setae (JV2-JV5, ZV2-ZV5). Ventral setae similar to those on dorsal idiosoma.

Sperm induction structures (Figures 22, 27‒30). Tubes of sperm induction system weakly developed (with well-separated tips), weakly sclerotized in narrow basal and medial part, broadened apically, and club-shaped; basalmost section connected to inner margin of coxa IV; in newly moulted specimens, bulbiform apex of tubes more or less reduced, and almost hyaline (unsclerotised).

Gnathosomal structures (Figures 23‒25, 35, 38). Corniculi elongated and horn-like; laciniae densely pilose, longer than corniculi; deutosternum with six rows of denticles; subcapitular setae smooth and needle-shaped (Figure 23). Epistome with subtriangular and regularly narrowed base, wider central neck and widened apical part densely crenelated on truncate anterior margin; basal part serrate on lateral margins (Figure 24). Fixed digit of chelicera shortened, seemingly truncate; with indistinctive terminal hook reduced to two small denticles, one subdistal tooth, and very robust (hypertrophied) pilus dentilis directed backward (Figures 25, 35, 38). Movable digit of chelicera longer than fixed digit, with a hook and one subapical tooth (Figure 35).

Legs. Leg setation normal for genus ( Mašán, 2007). Tarsus II with two spur-like distal setae, pl1 and pl2 (Figure 26).

Male. Idiosoma (Figure 39). Dorsal shield 470‒510 μm long and 250‒285 μm wide, elongated and suboval (length/width 1.78‒1.88). Sternal, genitiventral, peritrematal, metapodal, and anal plates fused together to form an entire holoventral shield bearing nine pairs of setae (not including three circum-anal setae); shield evenly reticulate on surface. Dorsolateral and ventral soft integument with ten pairs of setae (see diagnosis). Dorsal and ventral chaetotaxy, and other characters as in female.

Gnathosomal structures (Figures 31‒34, 36, 37, 40). Palptibiae slightly thickened medially (when compared with other palp segments), each bearing a pair of petal-like projections on proximal ventral surface, as in Figures 31‒34; inner petal markedly larger than outer one, but shorter than cross-sectional radius of palptibia. Cheliceral spermatodactyl elongated, ensiform, 75‒80 μm long (about 1.7‒1.9 times as long as movable digit of chelicera), slightly widened in proximal section and progressively tapering toward the tip; sperm ductus well defined (Figures 36, 37, 40).

Legs. Medial segments of legs II spurred on their distal ventral surface: femur with one robust spur, genu and tibia each with a peg-like spur, as in Figure 41. Femoral spur broadened medially, produced into widely rounded apex, with a small subdistal tubercle (Figure 41). Terminal part of tarsus II with only one spur-like distal seta, pl1 (Figure 42).

Etymology.

The specific name of the new species is derived from the Latin words “brevis” (short) and “pilum” (hair), and it alludes to the fact that the species has the shortest idiosomal setae among its congeners.

Taxonomic notes.

The main diagnostic character states for Pachylaelaps (Longipachylaelaps) brevipilis are the presence of shorter idiosomal setae (e.g., j5 <j5-z5, J1 ≈ ½ x J1-J2), the relative length of dorsal setae J4 and J5 (setae J5 negligibly longer than J4, about 1.04-1.14 times as long as J4), the existence of sexual dimorphism in the pilus dentilis (markedly enlarged and spiniform in female, minute and slender in male), the form of the tubular structures of the sperm induction system (tubes shorter, with club-like terminal part), the form and length of the cheliceral spermatodactyl (sword-like, less than twice as long as movable digit), and the length of the dorsal shield (small species, with dorsal shield 470-510 μm long in males, and 510-565 μm long in females).

The presence of relatively short dorsal setae (at least in a central row), along with subequal setae J4 and J5, is also the feature of three other Pachylaelaps (Longipachylaelaps) species, namely Pachylaelaps (Longipachylaelaps) bifurciger , Pachylaelaps (Longipachylaelaps) dubius and Pachylaelaps (Longipachylaelaps) silviae . The new species may be reliably distinguished from the above mentioned congeners by the characters presented in Table 1, and with the help of the identification key provided below.