Podapolipus gryllacridi, Lindquist & Sidorchuk, 2019

Lindquist, Evert E. & Sidorchuk, Ekaterina A., 2019, A new species of Podapolipus (Acari: Heterostigmata: Podapolipidae) from an Australian gryllacridid cricket (Orthoptera), with keys to orthopteran-associated species of the genus, Zootaxa 4647 (1), pp. 115-133 : 118-126

publication ID	https://doi.org/ 10.11646/zootaxa.4647.1.11
publication LSID	lsid:zoobank.org:pub:FF6B08B1-4FAC-4EE7-83CB-4328CF714350
persistent identifier	https://treatment.plazi.org/id/03DD0367-FFA3-0D6A-FF09-FD3F14D22B61
treatment provided by	Plazi
scientific name	Podapolipus gryllacridi
status	sp. nov.

Treatment

Podapolipus gryllacridi new species

( Figures 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 )

Diagnosis. Larval female: distinctive from all other described species of Podapolipus in having all dorsal and ventral idiosomatic setae, except the greatly elongated pairs of scapular setae sc 2 and caudal setae h 1, reduced to the size of microsetae, similar in size to pair e on tergite EF; in addition, prodorsal setae v 2 inserted slightly posterolaterad level of v 1, and tergite C separate from D. Adult male: distinctive from all other described species in having all dorsal idiosomatic setae, other than elongated scapulars sc 2, reduced to microsetae; in addition, prodorsal shield entire, with apex of aedeagus between bases of setae v 1, slightly behind shield’s anterior margin. On both larval female and adult male, legs II and III without claws; tibiae II and III with seta l´ setiform, and, femur II with one seta (v″ absent). Adult female: idiosoma lacking scaly or other ornamentation; leg I with a single seta, l′, located on dorsal face of femur; gnathosoma lacking setae; cheliceral stylets smooth.

Description.

Larval female (n=7). Figs 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 . Gnathosomatic capsule ( Figs 1A, B View FIGURE 1 , 4A View FIGURE 4 ) greatest width (45–54) slightly greater than middorsal length (43–53); dorsomedian apodeme evident along proximal half of capsule; dorsally, cheliceral seta ch (30–40) about 3X longer than ventral subcapitular seta su (12–17); cheliceral stylets (length 35–43) with three or four retrorse teeth along apical third of shaft; cheliceral levers slightly wider (13–15) than long (7–9); palpus with subapical cluster of four setal vestiges; palpal setae dFe (10–17) and dGe (6–10) strongly developed, dFe about as long as su; transverse distances between bases of setae: ch–ch 36–44, su–su 17–22, dFe–dFe 15–21, dGe–dGe 8–9; pharynx length 16–18, width 11–13.

Idiosomatic dorsum ( Figs 1A View FIGURE 1 , 2A View FIGURE 2 ), length 100–125, width at level of setae c 2 85–110. Prodorsal shield subtrapezoidal, greatest width (79–108) at level of setae sc 2 about 2.4X mid-line length (38–43), with three pairs of setae, of which v 1 and v 2 microsetae (0.5–1.5), sc 2 greatly elongated, attenuated (63–80); v 2 inserted at level slightly posterolaterad v 1. Tergite C with posterior margin somewhat concave but not surrounding lateral margins of tergite D; greatest width (85–110) at level near its anterior margin about 3X mid-line length (29–33), with setae c 1 and c 2 microsetae (1.5–3.0), c 2 inserted at level slightly posterolaterad c 1; tergite D somewhat inversely subtrapezoidal, greatest anterior width (50–68) about 2.3X mid-line length (16–31), with microsetae d (2–3); tergite EF inversely subtrapezoidal, basally overlapped by tergite D, greatest anterior width (32–48) nearly 3X mid-line length (11–21), with microsetae e (1.0–2.0); tergite H, fully covered by tergite EF, greatest width (13–18) about 1.8X length (3–10), with greatly elongated, attenuated setae h 1 (142–190), lacking any vestige of setae h 2; transverse distances between bases of idiosomatic setae: v 1 –v 1 28–36, v 2 –v 2 55 –62, sc 2 –sc 2 60–64, c 1 –c 1 59–65; c 2 –c 2 82–98, d–d 25–27, e–e 20–24, h 1 –h 1 contiguous. Tergites without discernible vestiges of cupules ia, im, ip.

Idiosomatic venter ( Figs 1B View FIGURE 1 , 2B View FIGURE 2 ). Prosternal region with apodemes 1 reaching to prosternal apodeme; apodemes 2 slightly short of reaching prosternal apodeme; prosternal apodeme reaches to posterior margin of coxisternal plates II; sejugal apodeme reduced, with short lateral remnant on either side; coxisternal plates I and II each with one pair of microsetae, 1a and 2a, well removed from apodemes 1 and 2, respectively; alveolar vestiges of setae 1b and 2b absent. Metasternal region with coxisternal plates III separated by wide strip of soft cuticle from prosternal region (this strip partly covers plates III on unengorged, specimens); coxisternal plates III with anterior margin strongly arched anteriorly, but lacking clearly formed apodemes; plates III with poststernal apodeme narrowly delineated medially, and with remnants of apodemes 3 and 4 flanking bases of legs III; plates III each with one pair of micro- setae 3b, lacking alveolar vestiges of 3a; all ventral microsetae of idiosoma subequal (1.5–3.0).

Legs ( Figs 1E View FIGURE 1 , 2 View FIGURE 2 C–E). Legs I thicker but similar in length to other legs, their lengths from trochanter bases to tarsal apices excluding apoteles: I 46 –52, II 42 –46, III 40 –45; lengths of segments similar to one another on each, and between, leg pairs. Number of setae (and solenidia in parentheses) on segments of legs I-II-III, respectively, trochanters 0-0-0; femora 3-1-0; genua 1-1-1; tibiae 6-4-4; tarsi 7(1)-5-5; homologies of leg setae denoted in Figs 2 View FIGURE 2 C–E, noting that the sixth seta on tibia I represents birefringent seta k, not solenidion ϕ. Leg I ( Figs 2C View FIGURE 2 , C′): femur with seta l′ slightly spinelike (6–8), d (inserted in nearly l″ position) greatly elongated, attenuated (30–42), v″ minute (2.0–2.5); tibial setae l′, l″, v ′ disparately short (l′ 6–15, l″ 3–7, v′ 4–8), v″ longer (12–20), d longest (25–32) but shorter than Fe d, k (3–5) untapered, bifid apically ( Fig. 1E View FIGURE 1 ); tarsus with solenidion ω (4–7) about half as long as tectals (tc ′ 10–13 slightly shorter than tc″ 14–15), pl′ peg-like, very short (2), pl″ slender, short (4–7), (pv) slightly spinelike, short (3–6), proximally flanking more strongly spinelike s (5); pretarsus with small bifid claw in adhesive pad ( Figs 1B View FIGURE 1 , 2 View FIGURE 2 C′). Leg II ( Figs. 2D View FIGURE 2 , D′): femur with seta l′ short (4–5), slightly spinelike, seta v″ absent; genual seta l ′ short, as on legs I, III (3–5), tibial setae slender, l′ short (2–4), (v) moderately long (11–15), d longest (18–23); tarsus with tc ′ bluntly spinelike, short (2–4), tc″ elongated, attenuated (20–26), pv′ short (3–6), slender, pv″ similarly short but slightly spinelike and flanking strongly spinelike, apically bifid u′ (3–6); pretarsus elongate (13–18), with adhesive pad apically, lacking rudiments of claws. Leg III ( Figs 2E View FIGURE 2 , E′) with genual, tibial, tarsal setae similar in form and size to those of leg II, but tarsal tc″ much more elongated (45–65); pretarsus formed as on leg II.

Adult male (n=5). Figs 1 View FIGURE 1 , 3 View FIGURE 3 , 4 View FIGURE 4 . Gnathosomatic capsule ( Fig. 4B View FIGURE 4 ) greatest width (33–34) ca1.2 greater than middorsal length (29–31); dorsomedian apodeme evident along proximal half of capsule; dorsally, cheliceral seta ch (35 – 40) about 2X longer than ventral subcapitular seta su (17–20); palpal setae dFe (3–4) and dGe (2) minute, much shorter than su; transverse distances between bases of setae: ch–ch 26–29, su–su 17–19, dFe–dFe 17–18, dGe–dGe 9–11; palpus with subapical cluster of four setal vestiges; cheliceral stylets (length 20 – 22) with two or three retrorse teeth along apical half of shaft; cheliceral levers clearly wider (10–11) than long (5–6); pharynx length 14–15, width 10–11.

Idiosomatic dorsum ( Figs 1C View FIGURE 1 , 3A View FIGURE 3 ), length 125–135, width at level of setae c 2 91–104. Prodorsal shield subtriangular, greatest width (80–95) at level of setae sc 2 about 1.6X mid-line length (54–63), with four pairs of setae, of which v 1, v 2 and sc 1 microsetae (1.0–1.5), sc 2 greatly elongated, attenuated (70–75); v 1 inserted at level on either side of aedeagal apex; genital capsule not extending beyond anterior margin of prodorsal shield ( Fig. 4C View FIGURE 4 ). Fused plate CD with posterior margin vaguely delineated, blending into extension of soft cuticle covering bases of legs III, with three pairs of microsetae of similar size (1.5–3.0); greatest width at level of setae c 2 (90–104) exceeds mid-line length including extension over bases of legs III (60–75); transverse distances between bases of idiosomatic setae: v 1 –v 1 15–19, v 2 –v 2 17–23, sc 1 –sc 1 15–22, sc 2 –sc 2 54–57, c 1 –c 1 61–67; c 2 –c 2 85–93, d–d 30–32. Tergites without discernible vestiges of cupules ia, im.

Idiosomatic venter ( Figs 1D View FIGURE 1 , 3B View FIGURE 3 ). Prosternal region with apodemes 1 united with prosternal apodeme; apodemes 2 slightly short of, or barely reaching prosternal apodeme; prosternal apodeme reaches to posterior margin of coxisternal plates II; sejugal apodeme reduced, with short lateral remnant on either side; coxisternal plates I and II each with one pair of microsetae, 1a and 2a, well removed from apodemes 1 and 2, respectively; alveolar vestiges of setae 1b and 2b absent. Metasternal region with weakly defined margins of coxisternal plates III separated by narrow strip of soft cuticle from prosternal region; coxisternal plates III with anterior margin strongly arched anteriorly and laterally, outward from weakly formed apodemes; plates III with poststernal apodeme united anteriorly with arch of apodemes 3, and extending posteromedially to level of setae 3b; separate remnants of apodemes 3 flank anterior bases of legs III; all ventral microsetae of idiosoma subequal (2.0–3.5). Transverse interval between bases of legs III 15–19.

Legs ( Figs 3 View FIGURE 3 C–E). Legs I thicker but similar in length to other legs, their lengths from trochanter bases to tarsal apices excluding apoteles: I 45 –50, II 46 –50, III 50 –56; lengths of segments similar to one another on each, and between, leg pairs. Number of setae and solenidia on segments of legs I-II-III as in larval female, including presence of seta l ′ on femur II, and apically bifid seta k on tibia I; homologies of leg setae denoted in Figs 3 View FIGURE 3 C–E. Leg I ( Figs 3C View FIGURE 3 , C′): femur with seta l ′ slightly spinelike (7), d greatly elongated, attenuated (35–47), v″ minute (2–3); tibial setae l′ (10–14), l″ (5), v ′ (8–10) of disparate lengths, v ′ strongly spinelike, incurved, v″ longer (15–18), d longest (30–40) but slightly shorter than Fe d, k untapered (4–5); tarsus with solenidion ω (6–7) about half as long as tectals (tc ′ 11 and tc″ 13), pl′ peg-like, very short (2), pl″ slender, short (5), (pv) slender, short (3–5), pv ′ proximally flanking spinelike s (5–6); pretarsus with vestigial lobe of single, blunt claw (ca 5) in adhesive pad. Leg II ( Figs 3D View FIGURE 3 , D′): fe- mur with seta l ′ short (4–5), slightly spinelike; genual seta l ′ short, as on legs I, III (4–5), tibial setae slender, l ′ short (3–4), (v) moderately long (14–17), d longest (17–28); tarsus with tc ′ short (4–5), bluntly spinelike, tc″ elongated, attenuated (32–40), pv ′ short (7), slender, pv″ similarly short (5–6) but slightly spinelike and flanking strongly spinelike, apically bifid u′ (4–6); pretarsus elongate (16–18), with adhesive pad apically, lacking rudiments of claws. Leg III ( Figs 3E View FIGURE 3 , E′) with genual, tibial, tarsal setae similar in form and size to those of leg II, but tarsal tc″ much more elongated (85–105); pretarsus formed as on leg II, and lacking rudiments of claws.

Engorged larva with pharate adult female (n=1; second, partly decomposed, specimen not measured). Figs 5D View FIGURE 5 , 7A View FIGURE 7 , A′. Almost globular (length of folded adult female 135, width 165, height 160, equal to idiosomal dimensions of larva), with larval cheliceral stylets splayed laterally in one specimen, contiguous in second; female inside with gnathosoma, stigmata, tracheae and legs as in adult (see below); idiosoma telescopically folded, showing 3 dorsal shields, all anteriorly: oval prodorsal (prod, 45 x70), horseshoe-shaped (sh2, 13x88) encompassing it and smaller oval shield posterior to second (sh3, 13x88); weak lateral sclerites seem present laterally from sh2 and sh3; no branching ducts (see below) visible; no small male or eggs found.

Physogastric adult female (n=5). Figs 5–7 View FIGURE 5 View FIGURE 6 View FIGURE 7 . Whitish with light-brown gnathosomatic capsule in alcohol. Gnathosomatic capsule ( Figs 5 View FIGURE 5 B–D, F–K; 6D–H; 7C, D) slightly longer than wide (55–65 per 50–55); no setae or respiratory apertures found; minute notch (n) present in some specimens between fused cheliceral bases; dorsomedian apodeme evident along proximal half of capsule, widened posteriorly, hollow, with paired tubules (tu) extending lateroposteriorly; palps (plp) visible at most as weakly circumscribed protrusions; cheliceral stylets (st), length 35–40, smooth, trough-shaped, with salivary ducts visible at SEM in cross-section (arrow in Fig. 6E View FIGURE 6 ); in natural position stylets contiguous, one specimen had remnants of stylostome (sst) attached to them; levers (lev) about as wide as long, about half length of stylets; pharynx (pha) slightly longer than wide (30–40 per 30–35).

Idiosoma ( Figs 5A View FIGURE 5 , F–K; 6A–D; 7B–D) sacciform, elongate (length 1215–2150, maximal width 260–510), shallowly bilobate caudally where genital opening situated; without discernible ornamentation, setae or cupules; prodorsal shield (prod) oval, considerably shorter (30–45, length may be underestimated due to foreshortening) than wide (50–70); horseshoe-shaped second shield (sh2, 11–12x70 –130), SEM shows its whole extent, while well-visible under light microscope only laterally, where multiple branching tubes (bd, possibly ducts of podocephalic canal system) originate; third shield indistinguishable; ovary with progeny staging from disk-shaped oocytes to fully formed larval females and adult males occupies ca 85% of idiosomatic volume; anterior and posterior compartments harbor granulate, possibly fat and/or glandular tissues. Idiosomatic venter ( Figs 5G View FIGURE 5 , J–K; 6C, D; 7C) shows glabrous coxisterna of single leg pair just posteriad, and pair of club-shaped stigmata (stg) ventrolaterad gnathosoma; one trachea (tr) extends from each stigma posteriorly.

Legs ( Figs 5E View FIGURE 5 , J–K; 6D; 7C) four-segmented (Tr, Fe, Ge, Ti-Ta), with single femoral seta (l′ Fe, 12–16) and blunt, strongly hooked, claw-like tarsal seta s (cl, 12–16).

Type material

All male and larval female specimens were collected from various locations on three raspy (“Gryllacri”) crickets, identified as “ Chauliogryllacris sp.” by David Rentz and Olivier Béthoux (subsequently described as Chauliogryllacris acaropenates Rentz, Su & Béthoux, 2018 ), collected from the subtropical northern peninsula of Australia: QLD ( Table 1 View TABLE 1 ) : (1) Adult male ( Gryllacri 1). 16°49′S, 145°40′E (GE) 151, Upper Stanton Rd ( Smithfield ), 104 m., 5 Feb. 2012, coll. DCF Rentz & O Béthoux , stop 12-7 GoogleMaps . (2) Adult female ( Gryllacri 3– 6 Feb). 16°06′10.1″S, 145°26′56.24″E, James Cook University , Rainforest Site , 46 m. 3–6 Feb 2016, coll. DCF Rentz & B. Richardson GoogleMaps . (3) Adult male ( Gryllacri 6 Feb m1). 16°57.734′S, 145°40.781′E (car), Crystal Cascades ( Redlynch Intake Rd ) nr Cairns , 67 m. 6 Feb. 2017, coll. DCF Rentz & O Béthoux , stop 7. HOLOTYPE: larval female, ex wing base of Gryllacri 1, deposited in ANIC GoogleMaps . PARATYPES: 6 larval females, 4 males, ex wing bases; 2 larval females, 2 males, ex thorax; 2 larval females, ex metathorax of Gryllacri 1; 3 larval females, detached ex female mesostigmatid gamasine mite # 1 ex hind wing of Gryllacri 1; 1 physogastric adult female and 1 engorged larva with pharate adult female, ex sternal apodemes of Gryllacri 3–6 Feb 2016. DEPOSITION: 4 larval females, 2 males, 1 physogastric adult female and 1 engorged larval female with dissected parts of adult female deposited in ANIC; 4 larval females and 2 males deposited in CNCI; 3 larval females, 2 males deposited in ZISP .

Additional material

About one hundred larval females, about a dozen adult males and about 30 adult females from the same specimens, removed and placed in alcohol or left on hosts, along with the dissected remnants of the hosts, deposited in the Australian Natural Insect Collection, CSIRO, Canberra. One physogastric female on SEM stub remains at Tyumen State University, Russia. Larval females, but no males, were also found attached to adult female gamasine mites attached to the wings and thoracic surfaces of Gryllacri 1 and Gryllacri 6 Feb m1 (see Table 1 View TABLE 1 ) and identified by us as a new species of the gamasine genus Berlesia Canestrini 1884 , to be described separately. These P. gryllacridi specimens will be distributed along with type specimens of the gamasine mite species.

Etymology

The new species name is based on ‘gryllacris’, a compound word meaning ‘chirping cricket’ and forming the name of a genus of crickets, with ‘gryllacrid-‘ as the stem. It is meant in reminiscence of the orthopteran family name Gryllacrididae , which includes crickets of the genus Chauliogryllacris , upon which these mites were found.

Differential diagnosis

Larval females and males of the new species are most similar to those of P. libratus Naudo, 1967 and P. transversus Lo, 1992 , in that larval females have tergital plates C and D separate, prodorsal setae v 1 inserted at least slightly anterior to the level of setae v 2, and males have the prodorsal plate entire, covering the aedeagal extension which opens near or slightly beyond that plate’s anterior margin. Larval females and males of the latter two species differ from those of P. gryllacridi in having tergital setae c 1, c 2 much longer (4– 5X) than their alveolar diameters, and the larval females also having tergital setae d much longer (ca 3X) than tergital microsetae e. Males of P. libratus further differ from those of P. gryllacridi in having setae d not reduced to microsetae; those of P. transversus differ in having the aedeagal apex opening anterior to, rather than between, the bases of vertical setae v 1. Adult females are not readily distinguishable from those of P. libratus and P. transversus , based on their descriptions.

Remarks

Among the some thirty genera of Podapolipidae , Podapolipus is exceptional in including species parasitic on hosts of three different orders of insects ( Husband 1986, Walter et al. 2009). Attempts to recognize subgroups of Podapolipus , reflecting parasitic specialization and adaptation to different orders of insects, have been problematical (Feldman-Muhsam & Havivi 1972, Husband 1989). The species from coleopterans form a group which is characterized by some attributes that may be apomorphic, though not exclusively so: larval females and males lack the posterior seta v″ on femur II, and males have tibial seta l′ modified, spinelike, on legs II and III. The two known species from Blattodea are characterized also by non-exclusive apomorphies: larval females and males have exceedingly small idiosomatic setae, other than scapular sc 2, and males have an aedeagus projecting beyond the anterior margin of the prodorsum. The species associated with orthopterans are more diverse, not readily defined as a group; however, as indicated by Husband (1986, 1989), they fall into two or three subgroups, which are somewhat indicated by attributes in our following keys. These keys are limited to descriptive or illustrative data indicated in available descriptions which are often inadequate and otherwise inconsistent in what attributes are presented.