Tarsonemus bistridentati, Magowski, Wojciech L. & Khaustov, Alexandr A., 2006

Magowski, Wojciech L. & Khaustov, Alexandr A., 2006, Two new species of Tars on em u s (Acari: Tarsonemidae) associated with bark beetles (Coleoptera: Scolytidae) from Crimea, Ukraine, Zootaxa 1359, pp. 31-55 : 43-54

Tarsonemus bistridentati n. sp.

( Figs. 21–40 )

Diagnosis

All instars: pharyngeal glandular bodies half as long as the length of the external part of the pharynx. Tarsi of leg I–III lacking one attenuate seta, femora I with 4 setae. Female: dorsal opisthosomal setae f shorter than c2, but longer than other dorsal opisthosomal setae, tegula ca. as wide as long, dorsal and ventral shields with fine, sparse ornamentation. Male: dorsal setae (except for f) attenuate, slender, smooth, sc2, c2, c1 and d strongly elongated. Dorsal ornamention includes fine, indistinct dimples, ventral ornamentation with scattered dimples and dense striae on coxal fields I–IV. Solenidion Φ located near the base of constricted tibia IV. Larva: dorsal setae v1 and c1–h2 serrate, stiff, tapering, sc1, sc2, c2 and h1 attenuate, slender; c2 longer than c1.

Females of T. bistridentati differ from the most similar congener, T. ips Lindquist , by having setae c2 about half as long as the distance between the bases of setae c2 and c1 (setae c2 almost as long as that distance in T. ips ) and by having ventral setae 2a about as long as 1a (setae 2a distinctly longer than 1a in T. ips ). Males of the new species can be distinguished from those of T. naegelei by having dorsal setae c1 and d slender and attenuate rather than stiff and strong, and by the ornamentation of the ventral podosomal plates which features lines, rather than dimples. Larvae of T. bistridentati differs from those of T. spatulaphorus and T. fraxini by having dorsal setae c2 attenuate and longer than c1 (setae c2 are shorter, T. fraxini , or subequal, T. spatulaphorus , to c 1 in the latter species).

Description: Female ( Figs. 21–27 )

Gnathosoma: ovoid-conical in shape; pharynx width 0.17x of the basal width of gnathosoma. with a pair of large glandular bodies posteriorly. Chelicerae small, short. Palpi more than twice as long as their basal width, each with a small palptarsal process and a minute seta. Palptibial claw indiscernible. Setae dgs slightly longer than vgs, setae pp indiscernible.

Idiosomal dorsum (length= 1.8x width): relative length of setae (v1: sc1: sc2: c2: c1: d: e: f: h): 1: 0.6: 1.8: 0.9: 0.8: 0.7: 0.7: 0.8: 0.7. Rostral shieldlet about 3x wider than long. Prodorsal shield about 1.4x wider than long. Tracheae with atria, no postatrial sacs or other structures present. Distance between setae v1 subequal to their length. Pits v2 indiscernible. Setae sc2 located at the midline of prodorsal shield, reaching to the posterior edge of prodorsal shield, the distance between their bases about 0.9x their length. Setae c2 extending more than halfway to bases of c1. Setae c1 extend three-fourths the distance from their bases to the posterior edge of tergite C. Setae d extend about one-third their length beyond the posterior edge of tergite D; distance between their bases about 2.5x their length. Bases of setae f separated by a distance equal to 1.4x their length. Distance between bases of setae h almost 2.5x their length. Dorsal setae slender, sharply pointed, smooth. Dorsal shields covered with fine, dimpled, uniform sculpture.

Idiosomal venter: apodemes 1 and anteromedian apodeme well sclerotized, the latter contiguous with, but not fused to, sejugal apodeme. Sejugal apodeme well developed, solid, with lateral segments bent strongly forward. Setae 1a located on apodemes 1, separated by a distance of 0.7x their length. Setae 2a located on apodemes 2; the distance between their bases about 2.5x their length. Ventral propodosomal plate concave anteriorly; its lateral edges with a bent ridge between trochanters I and II. Apodemes 3 extending only to condyli of trochanters III, apodemes 4 reaching beyond bases of setae 3b; posteromedian apodeme with pronounced anterior bifurcation. Setae 3b as long as 3a. Bases of setae 3a located at a distance of ca. 2x their length from the bases of setae 3b, and separated from each other by a distance subequal to, or slightly smaller than, the distance between the bases of 3b. Ventral metapodosomal plate concave anteriorly, with angularity between trochanters III and IV. Trochanters IV divided by an interval of ca. 3x their diameters. Tegula nearly as wide as long. The distance between bases of setae ps about 0.6x their length. Ventral shield ornamented uniformly as dorsum.

Legs: Proportions of free segments of legs: (I: II: III: IV): 1: 1.1: 1.2: 0.9. Leg chaetotaxy (for Fe, Ge, Tb and Ta): leg I: 4-4-6(2Φ)+7(1ω); leg II: 3-3-4-5(1ω); leg III: 1+3-4-4. Leg I: claw rather weak, similar to those of tarsi II and III. Spine-like seta s small, pointed, similar to setae u' of legs II and III. Setae u’ and u” discernible. Tibiotarsus ca. 3x as long as wide at base. Two subequal eupathidia (p' and p") inserted apically and one (tc") subapically on tibiotarsus I; tc' — the longest inserted more proximally. Tarsal seta pl' missing from segment. Solenidion ω with striated head, slightly larger than Ta ω II. Tibial solenidion Φ 2 shorter, Φ 1 longer, both with apparent striation; famulus k as long as Φ2; located at the same level as solenidia. Seta l' on genu attenuated, pointed. Femur I without ventral lobe. Femoral setae l" and l' slender; v” attenuate, d little stouter. Leg II: claws slender, hooked; empodium medium-sized, striated. Tarsal spine pl" slightly larger than solenidion Ta IIω, located at same level. Seta tc" not markedly longer than others on segment; pv" missing. Tibia cylindrical with v" the longest, and others shorter, subequal. Seta Ge l' stiffer than others on the segment. Femur with seta d slightly stiffer than other femorals. Leg III: claws as on leg II. Seta tc" over twice as long as others on segment. Tarsal pv" missing. Leg IV: free segments of leg as long as femurogenu and tibia III. Femurogenu about 3x as long as tibiotarsus. Tarsal seta tc" ca 2.6x as long as whole leg IV. Seta Tb v' longer than femurogenu but shorter than leg IV. Genual seta v' ca. 1.4x longer than femoral v'; located in a distance from the end of segment lesser than twice the distal width of Fege.

Measurements (holotype, followed by two paratypes from type locality in parentheses): Body and tagmata: Length of body: 210 (201; 195); length of idiosoma: 196 (190; 185); width of idiosoma: 107 (106; 105); length of gnathosoma: 35 (32; 33); width of gnathosoma: 22 (26; 23); length of pharynx: 8 (9; 9); width of pharynx: 4 (4; 4); dgs: 12 (12; 12); vgs: 10 (10; 10). Dorsum: length of PrS: 76 (72; 70); width of PrS: 103 (100; 100). Length of setae: v1: 24 (23; 23); sc1: 13 (14; 13); sc2: 42 (39; 42); c2: 21 (20; 25); c1: 18 (18; 18); d: 16 (17; 17); e: 16 (17; 17); f: 18 (18; 20); h: 15 (17; 16). Distances between setae: v1–v1: 26 (25; 25); sti–sti: 42 (42; 40); sc1–sc1: 49 (47; 48); sc2–sc2: 38 (39; 38); c2–c2: 101 (105; 100); c1–c1: 61 (65; 63); c1–c2: 31 (31; 25); d–d: 42 (42; 39); e–e: 75 (72; 71); f–f: 27 (24; 25); e–f: 25 (26; 24); h–h: 40 (39; 39). Venter: length of setae: 1a: 12 (11; 11); 2a: 12 (11; 12); 3a: 12 (12; 13); 3b: 12 (13; 12); ps: 13 (12; 12). Distances between setae: 1a–1a: 9 (7; 7); 2a–2a: 28 (28; 28); 3a–3a: 26 (26; 24); 3b–3b: 26 (28; 28); ps–ps: 8 (7; 8). Length of PrP: 50 (50; 50); width of PrP: 102 (100; 100); ap. 1–1: 15 (15; 13); ap. 2–2: 41 (39; 36); length of tegula: 14 (13; 14); width of tegula: 14 (13; 14). Leg segments and leg setae (length): Tbt I: 18 (18; 17); Ta I ω: 5 (6; 5); Τb Ι Φ 2: 3 (3; 3); Τb Ι Φ 1: 5 (6; 5); Tb I k: 3 (3; 3); Ta II ω: 3 (4; 4); Ta II pl": 4 (5; 4); Tbt IV: 10 (8; 9); Ta IV tc": 102 (102; 102); Tb IV v': 29 (28; 31); Fege IV: 27 (26; 26); Ge IV v': 14 (14; 13); Fe IV v': 10 (9; 10).

Male ( Figs. 28–34 )

Gnathosoma: similar to female, but slightly shorter. Width of pharynx about 0.13x of basal width of gnathosoma, length less than half of ventral length of capsule; with large glandular bodies. Idiosomal dorsum (length=1.6x width): relative length of setae (v1: v2: sc1: sc2: c2: c1: d: f): 1: 0.8: 2.1: 1.1: 1.6: 1.3: 1.3: 0.6. Prodorsal shield (PrS) about 1.4x as wide as long. Setae v1 separated by a distance of ca. 0.5x their length. Setae sc2 located slightly posteriad of the level of sc1. Setae sc1 located just behind the midline of prodorsal shield; over 0.7x of their length extending beyond posterior edge of prodorsal shield; bases at a distance of ca. 0.5x their length. Tips of setae c2 extending beyond the bases of c1. Setae c1 separated from d by a distance of 0.6x their length. Setae d extending well beyond the posterior edge of shield CD; separated by a distance of ca 1.1x their length. Setae f stiffer and half as long as c1 and d; bases separated from each other by a distance of ca.

1.5x their length; finely barbed. All other setae (v1 through d) slender, smooth, pointed. Cupuli im indiscernible. Genital capsule with hyaline rim small and narrow. Accessory stylets weak, located in posterior third of genital capsule. Dorsal shields covered with a fine, dense, uniform dimpled sculpture.

Idiosomal venter: anteromedian apodeme connecting anteriorly with apodemes 1, interrupted anterior to the proximal ends of apodemes 2, not fused to them. Sejugal apodeme continuous, weakly sclerotized. Coxal setae la separated by distance about equal to their length; setae 2a ca. 2x longer than 1a; bases separated from each other by a distance a little larger than their length. Length of setae 3a subequal to, or slightly shorter than, 3b; bases of 3a and 3b separated by a distance shorter than their length, and setae 3a separated by a distance of about half their length each to another, i.e. subequal to that between 3b. Setae 3b separated by a distance of about twice their length. All ventral setae attenuate, slender, smooth and sharply pointed. Apodemes 4 and 3 joining anteriorly with each other and with a strong posteromedian apodeme. Ventral propodosomal plate and coxal fields III and IV ornamented with fine dimples and clear, dense striae arranged radially from the mid point of the idiosoma; lateral fields of ventral metapodosomal dimpled.

Legs: Proportions of free segments of legs (I: II: III: IV): 1: 1.1: 1.2: 1.4. Leg chaetotaxy: leg I: 4-4-6(2Φ)-9(1ω); leg II: 3-3-4-5(1ω); leg III: 1-3-4-3. Leg I: claw as large as those of tarsus II and weaker than those on tarsus III. Seta s small, spine-like, approximate to u' of tarsi II and III. Tarsus slightly longer than 2x its basal width. Three eupathidia (tc", the shortest, p' and p") inserted apically on tarsus, one (tc') near midline of the tarsus. Solenidion ω inserted near the base of segment, with small, striated head.

Both fastigial eupathidia well developed, ft" at the level of tc', ft' at the level of solenidion ω, both similar in length to ω. Tibial solenidia Φ 2 smaller and Φ 1 slightly larger; eupathidion k, rod-like, intermediate in length between Φ1 and Φ 2, located at the same level as those. Seta l' on genu smaller but stiffer than others on segment, femoral seta d similar to others on the segment. Leg II: claws hooked; empodium moderate. Spine pl" thick, equal to solenidion ω, inserted slightly distad of it. Seta tc" longer than other setae of segment, reaching to the tip of empodium. Solenidion ω slightly thicker than ω on Ta I. Seta Ge l' slender, attenuate. Femoral setae d and l' slender, sharp. Leg III: claws and empodium larger than those of leg II. Setae p' and u' indiscernible. Seta tc" reaching well beyond the apex of empodium, tarsal tc" and tc' attenuate, pv" missing. Tibial seta v" the longest on the segment, all tibial setae attenuate, smooth. Leg IV: Free segments of leg IV longer than those of leg III. Tarsal claw weakly curved, blade-like, over 3x as long as basal width. Tarsus separate from tibia, with tc" shorter than pv' and u'. Tibia ca. 5x longer than tarsus, 3x longer (adaxial face) than its basal width, constricted in midlength. Tibial solenidion Φ approximately as large as tarsal solenidion of leg II, rod-like. Seta Tb v' long, attenuate, smooth, about 1.5x longer than free segments of leg IV. Femurogenu IV ca. 2.5x as long as wide at the base, with very small posterior protrusion at the base of the seta Fe v'; setae Ge v' and l” strong, attenuate, pointed, Fe v' the shortest and weakest of all on Fege and Ti IV, all attenuate, though strong. Seta v' on trochanter intermediate between Ge l" and Fe v'.

Measurements (three male paratypes): Body and tagmata: Length of body: 178–200; length of idiosoma: 144–173; width of idiosoma: 90–110; length of gnathosoma: 29–33; width of gnathosoma: 21–26; length of pharynx: 7–7; width of pharynx: 3–3; dgs: 10–14; vgs: 9–12. Dorsum: length of PrS: 42–50; width of PrS: 62–70. Length of setae: v1: 25–34; v2: 19–25; sc1: 50–72; sc2: 28–37; c2: 43–52; c1: 28–45; d: 33–42; f: 15–20; h: 2–3. Distances between setae: v1–v1: 15–17; v2–v2: 24–26; sc1–sc1: 31–33; sc2–sc2: 40–46; c2–c2: 79–92; c1–c1: 65–86; c1–c2: 36–40; d–d: 37–46; f–f: 24–29; h–h: 9–11. Venter: length of setae:; 1a: 11–14; 2a: 17–23; 3a: 18–25; 3b: 22–27. Distances between setae: 1a–1a: 10–13; 2a–2a: 24–28; 3a–3a: 39–51; 3b–3b: 44–55. Length of PrP: 40–46; width of PrP: 69–80; ap. 1–1: 15–17; ap. 2–2: 35–40; length of genital capsule 25–28; width of genital capsule 27. Leg segments and leg setae (length): Ta I: 14–16; Ta I ω: 4–5; Τb Ι Φ 2: 2–3; Τb Ι Φ 1: 4–5; Tb II k: 3–4; Ta II ω: 4–5; Ta II pl": 4–5; claw IV length: 13–17; claw IV width: 4–5; Ta+Tb IV: 18–35; Tb IV v': 95–120; Tb IV Φ: 4–5; Fege IV: 33–50; Ge IV v': 26–34; Ge IV l": 20–31; Fe IV v': 13–17.

Larva ( Figs. 35–40 )

Gnathosoma: a little smaller than in adults, otherwise similar. Pharynx width approximately 0.15x basal width of gnathosoma, and half as long ventral length of gnathosoma. Setae dgs equal to vgs. Cheliceral stylets and levers smaller and weaker than those in adults. Palpi pronounced; palptibial claw weakly discernible.

Idiosomal dorsum (length=1.9x width); relative length of setae (v1: sc1: sc2: c2: c1: d: e: f: h2: h1): 1: 1.2: 2.8: 1.3: 0.8: 1.1: 1.1: 1.4: 1.1: 2.5. Prodorsal shield (PrS) approximately 1.3x as wide as long. Bases of setae v1 separated by distance of 0.6x their length. Setae sc2 located in posterior fifth of PrS; extending beyond the posterior edge of PrS by 0.8x their length; bases separated by a distance of about 0.8x their length. Setae c2 extending 0.8x of distance to bases of c1. Bases of setae c1 separated by a distance of 5x their length. Half the length of setae d extending beyond the posterior edge of tergite D; separated by distance of 1.7x their length. Bases of setae e separated by a distance of ca. 2x their length; distance to base setae f ca. 0.6x their length. Bases of setae f separated by distance of ca. 0.8x their length. Bases of setae h2 separated by a distance subequal to their length; h1 by a distance as long as their 0.2x their length. Cupuli im and ih indiscernible; ia located far anteromedially of bases of d. Dorsal setae sc1, sc2 and c2 slender, sharp, smooth; v1 and c1 through h2 stiff, blunt, barbed, h1 attenuate, sharp, barbed. Dorsal shields smooth.

Idiosomal venter: apodemes 1 and 2 and anteromedian apodeme distinct; the latter continuous with posteromedian ends of apodemes 2. Setae 1a the shortest, bases separated by a distance of ca. 2.6x their length. Bases of setae 2a separated by a distance of 3.7x their length. Setae 3a longer than 1a, 2a and 3b, separated by a distance of 1.6x their length from bases of 3b. Setae 1a, 2a stiff, sharply pointed, 3b stiff, blunt, 3a slender, sharply pointed, smooth. Two pairs of minute setae ps present between and anteriad of bases of h1. Ventral shields smooth; ventral plates separated by an area of densely striated pleura.

Legs: Proportions of free segments of legs (I: II: III): 1: 0.9: 1.1. Leg chaetotaxy: leg I: 4-4-6(1Φ)-5(1ω); leg II: 3-3-4-4(1ω); leg III: 1-3-4-3. Leg I: Claws relatively weak, as on legs II and III. Spine-like seta s, similar to u' on tarsi II and III. Tarsus ca 1.6x as long as basal width. Eupathidion tc" longer than tc', both located apically. Solenidion ω approximately as large as Ta II ω. Solenidion Φ 1 with striated head, apparently longer than famulus k. Seta l' on genu similar to others on the segment. Setae l' and d on femur delicate, pointed. Leg II: Claws and empodium slender. Spine pl" very short, blunt, located distally and adaxially to the level of ω. Seta tc" longer than tc', though not reaching to the distal edge of empodium. Seta Ge l' small, pointed. Seta l' on femur very short, stiff, blunt; d more slender and longer. Leg III: Claws as on leg II. Seta tc" more than twice as long as tc', reaching beyond the edge of the empodium. Tibial setae d, v' and v" attenuated, slender.

Measurements (one larval paratype): Body and tagmata: Length of body: 185; length of idiosoma: 163; width of idiosoma: 85; length of gnathosoma: 28; width of gnathosoma: 22; length of pharynx: 7; width of pharynx: 3; dgs: 8; vgs: 8. Dorsum: length of PrS: 48; width of PrS: 62. Length of setae: v1: 15; sc1: 18; sc2: 42; c2: 20; c1: 12; d: 17; e: 17; f: 21; h2: 17; h1: 38. Distances between setae: v1–v1: 9; sc1–sc1: 39; sc2–sc2: 35; c2–c2: 74; c1–c1: 60; c1–c2: 25; d–d: 29; e–e: 35; f–f: 17; e–f: 10; h2–h2: 19; h1–h1: 9. Venter: length of setae: 1a: 5; 2a: 6; 3a: 10; 3b: 6; ps: 5. Distances between setae: 1a–1a: 13; 2a–2a: 22; 3a–3b: 16; ps–ps: 3–5. Length of PrP: 34; width of PrP: 57; ap. 1–1: 18; ap. 2–2: 36; length of HPs: 24; width of HPs: 32. Leg segments and leg setae (length): Ta I: 9; Ta I ω: 3; Τb Ι Φ 1: 4; Tb I k: 3; Ta II ω: 3; Ta II pl": 2.

Material

Female holotype, 3 male paratypes, 1 larva paratype, in the galleries of Pityogenes bistridentatus Eichhoff, 1878 , under the bark of Pinus pallasiana D.-Don., Yalta, Crimea, Ukraine, 31. 08. 1996, leg. A. A. Khaustov; 3 female paratypes, in the galleries of Pityogenes bistridentatus , under the bark of Pinus pallasiana, Yalta , Crimea, Ukraine, 15. 05. 1997, leg. A.A. Khaustov.

Remarks: This species was listed in Khaustov and Magowski (2003) as " Tarsonemus sp. near ips Lindquist, 1969 ".

Figures

FIGURES 21 – 23. Tarsonemus bistridentati, female holotype. 21, idiosoma; 22, gnathosoma dorsum; 23, gnathosoma venter.

FIGURES 24 – 27. Tarsonemus bistridentati, female holotype. 24, leg I; 25, leg II; 26, leg III; 27, leg IV.

FIGURES 28 – 30. Tarsonemus bistridentati, male paratype. 28, idiosoma; 29, gnathosoma dorsum;

FIGURES 31 – 34. Tarsonemus bistridentati, male paratype. 31, leg I; 32, leg II; 33, leg III; 34, leg IV.

FIGURES 35 – 37. Tarsonemus bistridentati, larva paratype. 35, idiosoma; 36, gnathosoma dorsum; 37, gnathosoma venter.

FIGURES 38 – 40. Tarsonemus bistridentati, larva paratype. 38, leg I; 39, leg II; 40, leg III.