Antennoseius (Vitzthumia) pyrophilus, Beaulieu & Déchêne & Walter, 2008

Beaulieu, Frédéric, Déchêne, Andrea D. & Walter, David E., 2008, Phase morphs and phoresy: New species of Antennoseius (Vitzthumia) mites (Acari: Mesostigmata: Ascidae) associated with pyrophilous carabids (Carabidae: Sericoda spp.) in Alberta, Canada, Zootaxa 1961 (1), pp. 37-57 : 48-51

Antennoseius (Vitzthumia) pyrophilus sp. nov.

( Figs 20–28 )

Material examined. ALBERTA: Holotype. Female, under elytra of Sericoda bembidioides Kirby , ex pitfall trap in burned boreal forest near, Chisolm, Alberta (54°56’N, 114°7’W), 8 August 2002. Paratypes: 9 female from under elytra of Sericoda quadripunctata (DeGeer) and S. bembidioides ex pitfall traps, same location as holotype, July–September 2002; 1 female each under elytra of Calathus ingratus Dejean and Agonum placidum (Say) , same collection data except 22 July 2002.

Diagnosis. Antennoseius species with adult females of smooth (phoretic) morph lacking granular tubercles on shields and soft cuticle; dorsal and peritrematal shields with reticulate pattern and with fine, longitudinal or oblique lineae on most of the anterior dorsal shield and the margins of the posterior dorsal shield; ventral shields weakly lineate. Podonotal shield with 19 pairs of setae, including an additional pair x, laterad s4; opisthonotal shield with 15 pairs of setae. All idiosomal setae simple, of similar length. Sternal shield bearing st1-2 and stp1-2; postero-lateral margins eroded leaving st3 and stp 3 in soft cuticle; st 4 in soft cuticle. Tectum with anterior margin mostly smooth. Hypostomal setae h1-3 and pc simple; palpgenu and palptibia with two and one very stout, spur-like setae dorso-distally, respectively; al of palpfemur, al1-2 of palpgenu, and al1-2 of palptibia sword-shaped. Leg I with ambulacrum; seta pl2 absent on tibia III. Most leg setae simple, with few dorsal setae on trochanter and femora sparsely barbed; dorsal seta on trochanter I, pd1-2 and pl1-2 of femur I, pd3 of genu I, ad1 and pl1 on tibia I thickened, spur-like or spine-like. Tarsus I without conspicuously elongate subapical setae.

Description of phoretic female. Soft cuticle evenly plicate. Anterior dorsal shield (245–260 long × 212– 232 wide) and posterior dorsal shield (193–207 long × 209–231 wide) both with reticulate ornamentation throughout ( Fig. 20 ). Most of the anterior dorsal shield and edges of the posterior dorsal shield covered with lineae, giving a rugose appearance. Anterior dorsal shield with 19 pairs (j1-6, z1-6, s1-6, x) of mostly short (20–25), simple setae, j1 (13–16) and z1 (15–18) shortest. Posterior dorsal shield with 15 pairs of mostly short (18–23), acicular setae (J1-5, Z1-5, S1-5); Z5 (20–27) longest. Marginal setae r2-6 (20–24) and R series (15– 20) short, simple, in soft lateral cuticle; between 8 to 12 R setae. Peritreme approaching seta z1, peritrematal shield narrow, lineate, joined to anterior dorsal shield near seta z1. Dorsal shields with 22 pairs of discernible pore-like structures (9 on anterior shield, 13 on posterior shield), of which 6 appear secretory (gland pores, gd, Fig. 20 ) and 16 non-secretory (lyrifissures); gland pore gdZ4 appears to have migrated in soft cuticle laterad posterior shield. Gland pores are slit-shaped and lyrifissures are generally ovoid except mostly those laterad setae j1.

Tritosternum ( Fig. 21 ) base (44–46 long × 11–13 wide for most length, 19–21 wide at proximal end) with 14–17 denticles fringing base of laciniae (65–69). Sternal shield ( Fig. 22 ) attached to lineate pre-sternal lobes, with weak lineate pattern, bearing simple setae st1-2 (19–25) and lyrifissures stp1-2; shield notched or eroded postero-laterally, median process irregularly produced, dissipating posteriorly; small endopodal plate posteriad coxa II separated from sternal shield by soft cuticle. Setae st3-4 (21–24) and lyrifissure stp 3 in soft cuticle. Setae st1-3 with a lightly swollen base and acuminate tip. Epigynial shield ( Fig. 22 ) narrowly lanceolate, 125–139 long × 37–41 wide, with lineate ornamentation; setae st5 (23–24) in soft cuticle. Metapodal plates oval (diameter 13–20). Anal shield suboval (73–77 long × 57–62 wide), faintly lineate with 3 simple circumanal setae, para-anal setae (17–20) almost as long as post-anal seta (19–24). Soft cuticle with simple ventral setae JV1-5, ZV1-5, and 10–16 pairs of submarginal setae (UR series) ( Figs 20, 22 ).

Gnathosomal tectum ( Fig. 23 ) with mostly smooth margin, dorsal surface with a transverse line of denticles; subcapitulum ( Fig. 24 ) with 7 rows of 4–13 deutosternal denticles; corniculi (30–34) horn-like; hypostomal setae h1-3 and palpcoxal seta pc simple (17–25). Fixed digit (28–30, from dorsal lyrifissure) of chelicera ( Fig. 25 ) with short, rounded dorsal seta (8), row of 10–11 serrations, setiform pilus dentilis, and subapical offset large tooth; movable digit (38–39) bidentate, paraxial ridge leading to a ventral projection typical for the genus. Palps (128–134) ( Fig. 26 ) about as long as subcapitulum (from base to tip of corniculi: 124–130); palpal setation normal for genus, but palpgenu and palptibia with respectively two and one very stout, spur-like setae dorso-distally; anterolateral setae of femur, genu and tibia ensiform; pd1 of palpfemur, ad2 and pd2 of palpgenu and many dorsal setae of palptibia swollen basally with a fine, acuminate tip; palp apotele 2-tined.

Excluding ambulacra, lengths of leg I 402–424, leg II 294–312, leg III 286–307, leg IV 361–388 ( Figs 27–28 ). Tarsus I with ambulacrum (21–26, excluding stalk) on short stalk (11–12), claw subequal in size to claws of tarsi II–IV. Ambulacra II–III 28–32, ambulacrum IV 33–38. Tarsi II–III (85–93) and IV (113–119) about as long as combined length of tibia and genu; tarsus I (106–112) slightly shorter than combined length of tibia (44–54) and genu (70–74); tibiae II–III (38–44) and IV (56–62) equal or subequal to genua. Setation of leg segments I–IV, respectively: coxae 2-2-2-1, all setae normal or slightly swollen basally; trochanters 6-5- 5-5, dorsal seta of trochanter I thickened, spine-like, and sparsely barbed ( Fig. 27 ); dorsal seta on trochanter II–IV also sparsely barbed, and one pl on trochanters III–IV slightly swollen basally; femora 12-11-6-6, femur I with pd1 and pl1 spur-like (thicker), pd2 and pl2 spine-like and pd2 with a few barbs ( Fig. 27 ), most dorsal setae on femora II–IV sparsely barbed; genua 13-11-9-9, seta pd3 of genu I short, blunt and spur-like; tibiae 13-10-8-10, seta pl2 absent on tibia III ( Fig. 28 ), seta ad1 and pl1 on tibia I thickened, somewhat spine-like; tarsi II–IV 16-16-16, plus two short apical seta-like processes. Subapical setae (30–41) on tarsus I not conspicuously longer than other setae on tarsus.

Etymology. The specific name pyrophilus was chosen for the mite’s association with carabids of the genus Sericoda , which thrive in recently burned forests.

Remarks. Females of A. pyrophilus can be distinguished from any other species in the genus by the following combination of characters: the very strong spur-like dorsal setae on palpgenu and palptibia ( Fig. 26 ), the fine, (almost) longitudinal ridges on the dorsal shields, the almost completely smooth margin of the tectum, the spur-like or spine-like setae on trochanter, femur, genu and tibia of leg I, and the absence of conspicuously elongate subapical setae on tarsus I.

As for A. perseus , phoretic females of A. pyrophilus were mostly found on the ventral surface of the beetles' elytra.

Figures

FIGURES 20–23. Antennoseius pyrophilus n. sp., female, phoretic form. 20, Dorsal shields; 21, Tritosternum; 22, Ventral shields; 23, Tectum and its variants.

FIGURES 24–28. Antennoseius pyrophilus n. sp., female, phoretic form. 24, Subcapitulum; 25, Right chelicera, lateral view; 26, Left palp (tarsus not shown except palp apotele), dorsal view; 27, Right leg I (except tarsus), postero-dorsal view; 28, Right leg III, postero-dorsal view.