Pedrocortesella enigma, Hunt, 1996

Hunt, Glenn S., 1996, A review of the genus Hexachaetoniella Paschoal in Australia (Acarina: Cryptostigmata: Pedrocortesellidae), Records of the Australian Museum 48 (3), pp. 223-286 : 251-254

Pedrocortesella enigma n.sp.

Figs 20 , 21

Type material. Tasmania: HOLOTYPE adult, ANIC, Mount Victoria , 41°20'S 147°49'E, 900 m, pyrethrum knockdown from trees, H. Mitchell and R. Coy, 25 November 1989 ; PARATYPE adult, AM KS46642 SEM stub no. S/418 (ill.), Mount Michael , 41°10'S 148°00'E, pyrethrum knock-down from tree, R. Coy, 28 November 1989, 1 adult .

Diagnosis. Body length medium, about 540)lm; sensillus terminates in rounded club, not flattened blade; notogaster reticulate-alveolate; 5 pairs long notogastral setae, genitoanal chaetotaxy 7:1:3:3, genital setae in arcuate file, insertion of seta ad3 adjacent to anterior 50% of anal valve; claw stalk long.

Description

ADULT: Body: brown; length 540)lm. Cerotegument: body generally with thin veneer of cerotegument; reticulations on prodorsum and notogaster with numerous cushion-like grains of cerotegument, some stellate tubercles often coalescing into "stitched" crest ( Fig. 20 E-F). Setae le, ro and notogastral setae with tapering basal fringes of cerotegument. Prodorsum: integument more or less uniformly reticulate-alveolate including area between bothridia; foveae without visible pores; carina between le and ro absent; le dorsolateral and situated close to anterior of rostrum, distance between them about 0.5 distance between ra, not arising from large pit, ro ventrolateral, insertion not quite visible from above. Pedotectal tooth strongly curved anteriad. Bothridium abutting notogaster but not closely adpressed, posterior wall complete, wall diamond shaped as in P propinqua ( Fig. 20A,D ), posterolateral carina strong, close to notogaster; sensillus clavate and rounded, not with flattened blade, densely tuberculate, length about 0.5 interbothridial distance ( Fig. 20 B-D); posterior margin of prodorsum forming a smooth arc between bothridia; in vestigial, without supporting apophysis; removed from edge of dorsosejugal furrow. Exuvial scalps: not seen. Notogaster: oval, length:width without scalps 350:300. Intramarginal depression similar in shape to P propinqua . Notogaster strongly alveolatereticulate, not perforated by pores ( Fig. 20D ); posterior margin not invaginate when viewed from above, without carina between setae pi when viewed posteriorly ( Fig. 20F ). Fissura ia and ip oblique to sagittal plane, im subperpendicular; 5 pairs of long notogastral setae ( Fig. 20A,F ), with thick cerotegument coating at base, not arising from small pits; hI moderately separated, each located inside posterior margin; pI inserted about midheight on posterior flank, closer together than hI; lpx, p2x and p3x arise along posterolateral flank, their insertions visible from above, lpx closest to fissura ip inserted just posterior to it. Gnathosoma : rutella basally with without concave flexure, with strong transverse striations, pointed basal mesad process absent ( Fig. 21C,E ); pedipalp not examined. Epimeral region: moderately convex anterior to genital valves, not tending to overhang them. Genitoanal region: separation of anal and genital vestibules relatively broad but with interruption to ventral plate microsculpture, wide mesal isthmus without strong transverse grooves between the vestibules (Fig. 2IA,G), Ventral plate reticulate-foveate. Genitoanal chaetotaxy 7:1:3:3; genital setae essentially in arcuate file but with g5 placed about 0.5 valve length; gI inserted lateral to inner anterior corner of valve in marginal notch; g7 inserted at inner posterior corner, in marginal notch; setae ag inserted at level between g6 and g7; setae adI distinctly postanal, ad3 inserted level with anterior 30% of anal valve, subequal to ad 2 in separation from valve. Legs. Distal apophysis of tibia overlaps about 30% of tarsus (Fig. 2ID). Tarsal cluster of leg I placed distodorsally on apophysis, fi", omega 1 and 2 enclosed in common rim (Fig. 2 ID), no partition separating fi" from omega 1 and 2, latter widely separated; tarsus without distal recess for receiving retracted unguinal complex, claw stalk long.

Comments. This species strongly resembles P propinqua in many respects: the wide separation of genital and anal vestibules, the arcuate arrangement of genital setae; the anterior position of setae ad3; the length and disposition of notogastral setae; the vestigial interlamellar setae; and the shape of the bothridium. It differs in having three pairs of anal setae and a clavate sensillus, the latter being generally regarded as an adaptation to arboreal life ( O'Dowd et al., 1991). The species is probably an arboreal representative of the species group suggested for P. propinqua and P. bannisteri (see General Discussion).

Etymology. The specific epithet refers to the puzzling three pairs of anal setae, quite uncharacteristic for Pedrocortesella .

Distribution. Mountainous rainforest areas, north-eastern Tasmania.

Figures

Fig . 20 . Pedrocortesella enigma n . sp . A , body , dorsal , arrows left to right label setae hi , Ip " p 2 " p 3 x ; B , prodorsum , frontal ; C , body , lateral ; D , prodorsum , dorsal ; E , notogastral integument ; F , notogaster , posterior ( part ) , arrows left to right label setae pi , hi , lp " p 2 " p 3 x Scale bars : A-D = 100 J .. lm ; F = 50 J .. lm ; E = 20 J .. lm .

Fig. 21. Pedrocortesella enigma n.sp. A, body, ventral; B, leg 1 tibia (distal) and tarsus, antiaxial; C, subcapitulum; D, leg I tarsus, dorsodistal; E, rutellum; F, genital valves; G, anal valves. Scale bars: A = 100 /lm; C,F,G 50 /lm; B,D,E = 20 /lm.