Steneotarsonemus (Neosteneotarsonemus) ramus, Lin & Zhang, 2005

Lin, Jian-Zhen & Zhang, Zhi-Qiang, 2005, New Zealand species of Steneotarsonemus Beer (Acari: Tarsonemidae), Zootaxa 1028 (1), pp. 1-22 : 3-12

Steneotarsonemus (Neosteneotarsonemus) ramus sp. nov.

( Figs. 1–12 )

Diagnosis. Bothridial setae narrowly lanceolate, branched near distal 1/3 of its length. Apodeme 3 inverse v­shaped in female. A transverse apodeme present on dorsum of gnathosoma in male.

Adult Female. Length 320 (304–335, 307) from anterior end of gnathosoma to posterior end of idiosoma. Combined length of legs I–IV (from tip of tarsus to base of femur excluding trochanters) 220 (214–235, 218).

Dorsal idiosoma ( Fig. 1 ). Idiosoma elliptical, length 291 (277–306, 277), about 1.6 times of maximum width [149 (140–172, 177)] at level of insertion of trochanter III. Prodorsal shield trapezoid, posterior width 98 (89–106, 96), about equal to medial length [98 (93–101, 96)]; its anterior margin slightly convex and striate; its lateral margins slightly concave. Stigmata opening lateral to insertions of vertical setae; distance between stigmata opening and v 1 4 (3–4, 4) long; tracheal trunks extending posteriorly through an atrium with a diameter of 5 (4–6, 5) to level of coxisternal plate III. Setae v 1 stout, located at same level of stigmata opening; their length [16 (15–18, 15)] less than distance between insertions [v 1 ­v 1 32 (32–33, 33)]. Bothridial setae sc 1 19 (18–21, 19) long, narrowly lanceolate, with a branch near 1/3 from its distal end; scapular setae sc 2 slender, tapered, 69 (60–80, 60) long, about 1.2 times as long as distance sc 2 ­sc 2 [53 (51–56, 52)].

Setae of opisthosomal tergites smooth, simple. Setae c 1 poorly tapered, inserted near middle level of C; its length 15 (14–17, 15). Setae c 2 smooth, finely tapered, inserted anterolaterad of c 1; length 19 (15–25, 15); distance c 1 ­c 1 [55 (52–60, 53)] half of c 2 ­c 2 [122 (116–130, 122)]. Setae d inserted posteriorly at 4/5 level of D; length [9 (8–10, 10)] less than 1/5 of distance d­d [52 (51–53, 51)]. Setae e and f inserted posterior half of EF; distance e­e 85 (82–87, 86), about 2.7 times of f­f [32 (30–35, 32)]. Setae h [12 (11–12, 11)] shorter than distance h­h [39 (37–42, 42)].

Ventral idiosoma ( Fig. 2 ). Prosternal apodeme 53 (50–56, 52) long, extending from its union with apodemes 1 to posterior margin of coxal sternal plate II, becoming trifurcate distally. Apodeme 2 not connecting medially with prosternal apodeme. Sejugal apodeme leaving lateral remnant on each side. Coxal setae 1a 3 (3–4, 3) long, inserted on anterior part of apodeme 1, shorter than 2a [6 (5–7, 5)]. Posternal apodeme weakly sclerotized, leaving two remnants. Apodeme 3 length 54 (47–60, 53), extending from articulation point with anterior extremities of trochanters III to anterolaterad of coxal setae 3a, with an inverse v­shaped. Apodeme 4 extending for a distance posterolaterad of insertions of coxal setae 3b. Its anterior 1/3 with a small projection. Coxal setae 3a [32 (22–40, 22)] longer than 3b [7 (6–8, 6)]. Tegula semicircular in shape; its length [14 (11–16, 16)] less than basal width [23 (22–26, 23)]. Posterolateral extensions of coxisternal plates IV overlapping each other medially beneath tegula. Aggenital plate covered with some part of pseudanal plate. Setae ps slender, inserted near posterior margin of PS; length 16 (14–17, 15), shorter than distance ps­ps [17 (15–18, 17)].

Legs ( Figs. 3–6 ). Excluding trochanters, leg I 63 (56–70, 64,) long and leg II 62 (59– 70, 65) long. Leg III [75 (71–80, 74)] longer than legs I or II. Leg IV 54 (51–57, 53) long, slender, femorogenu [44 (42–46, 43)] more than 4 times as long as tibiotarsus [10 (9–10, 9)]. Medial claw of leg I strongly developed, unguiform, on well­developed apotele. Legs II–III each with well­developed membranous pulvillus and symmetrically paired lateral claws.

Number of setae and solenidia on leg I (femur to tarsus): 3–4–6(2)–7(1). Femur I with setae d and pair (l) inserted near mid­length of femur I; Genu I with pairs (v) and (l) situated near mid level of segment. Tibial sensory cluster with 2 (7 long), slightly clavate, 1 minute, 4 (3–4, 4) long, barely discernable and famulus k spinelike, bluntly pointed, 3 (3–4) long. Tibiatarsus with clavate, 6 (5–7) long, inserted twice of its length to proximal end of tibiotarsus I.

Number of setae and solenidia on leg II (femur to tarsus); 3–3–4–5(1). Femur II with setae d shorter than l’ and v”. Genu II with seta v shorter than pair of l’ and l”. Tibia II with v nearly equal to v”, seta d longest on segment, but seta l’ shortest; all setae inserted near mid­length of tibia II; Tarsus II with clavate, 6 long, located basal 1/3 of tarsus II. Seta tc” nearly twice as long as seta tc’.

Number of setae and solenidia on leg III (femur to tarsus): 1+3–4–4. Femorogenu III with femoral v inserted laterally basal 1/3 of segment, shorter than l’G and v’G. Tibia III with v’ about twice as long as v”; seta v” inserted distally, but v’ proximal to mid­length of tibia III. Tarsus III with tc” more than 3 times as long as tc’.

Femorogenu IV with v’F [7 (6–8, 6)] 2/3 as long as genual v’G [11 (10–12, 12)]. Tibiatarsus with v’Ti 20 (19–21, 20) long, less than 1/5 as long as attenuated tarsal tc” [78 (75– 80, 75)].

Gnathosoma. Gnathosomal capsule 38 (34–40, 38) long and shorter than its maximum width [42 (41–43, 42)]. Dorsal gnathosomal setae 15 (14–16, 15) long, more than twice as long as ventral pair [6 (5–7, 7)]; palpcoxal setae minute. Palpi short, cylindrical, appressed to rostrum. Cheliceral stylets slightly curved basally. Pharynx with thin muscular, sclerotized lateral walls, its length 13 (12–15, 13) nearly twice as long as its maximum width 7 (6–8, 7).

3

4

5

6

Adult male. Length 232 (225–242, 225) from anterior end of gnathosoma to posterior end of idiosoma. Combined length of legs I–IV (from tip of tarsus to base of femur excluding trochanters) 220 (199–238, 199).

Dorsal idiosoma ( Fig. 7 ). Idiosoma length [209 (204–220, 204)] about 1.6 times of maximum width [113 (106–119, 106)] at level of insertion of setae c 2. Prodorsal shield trapezoid, posterior width 81 (76–85, 76), slightly longer than medial length 70 (67–73, 67); its anterior margin convex; its lateral margins slightly concave at level of vertical setae. Setae v 1 13 (12–16, 12), shorter than distance between their insertions v 1 ­v 1 23 (20– 24, 20). Second vertical setae v 2 [18 (17–22, 17)] longer than first vertical setae, both pairs longer than distance v 1 –v 2. Scapular setae sc 1 longest of idiosoma, about 4.7 times as long as v 1, and about 1.5 times as long as distance between their insertions. Second scapular setae sc 2 22 (20–24, 22) longer than vertical setae v 1 or v 2, but shorter than first scapular setae sc 1, slightly longer than distance between sc 1 and sc 2 in nearly oblique longitudinal alignment with former 3 setae. Metapodosomal plate CD with setae c 2 [28 (25–32, 25)] slender, longer than c 1 [11(8–12, 8)] and d [16(14–17, 16)], which are poorly tapered in nearly transverse alignment in posterior part of plate. Subterminal plate EF with setae f 11 (10–11, 10) long. Genital capsule heart­shaped, 41 (39–42, 39) long, 33 (31–36, 31) wide, with caudal setae h minute, 3 long.

Ventral idiosoma ( Fig. 8 ). Prosternal apodeme extending from its union with apodemes 1 to level of inner end of apodeme 2, interrupted, second part not reaching to sejugal apodeme. Apodeme 2 not connecting medially with prosternal apodeme. Sejugal apodeme reduced to lateral fragment postlaterad of setae 2a. Coxal setae 1a 5 (4–6, 5) long, inserted well behind apodeme 1. Setae 2a 4 (4–5, 4) long, inserted near middle coxisternal plate II. Posternal apodeme divided posteriorly, its anterior end reaching to level of setae 3b. Apodeme 3 length 44 (40–48, 40), extending from articulation point with anterior extremities of trochanters III beyond base of coxal setae 3a. Apodeme 4 fully developed at base from articulation point with anterior end of trochanters IV, becoming more weakly developed toward anterior end of apodeme 3. Coxal setae 3a [27 (20–32, 30)] more than 5 times as long as 3b [5 (4–7, 4)].

Legs ( Figs. 9–12 ). Excluding trochanters, leg I 63 (52–68, 60) long and leg II 62 (51– 70, 51) long. Leg III [70 (65–75, 65)] longer than legs I or II. Leg IV 58 (52–60, 52) long. Medial claw of leg I strongly developed, unguiform, on well­developed apotele. Legs II– III each with well­developed membranous pulvillus and symmetrically paired lateral claws.

Number of setae and solenidia on leg I (femur to tarsus): 4–4–6(2)–8(1). Femur I with setae d, v” and pair (l) inserted near mid­length of femur I; Genu I with 2 pair of setae, namely (v) and (l), pair (v) situated nearly mid level of segment, but pair (l) located near base of segment. Tibial sensory cluster with 1 6 (6–7, 6) long, slightly clavate, 2 minute, 4 (3–4, 3) long, and famulus k spinelike, bluntly pointed, 3 (3–4) long. Tarsus with

clavate, 6(5–6, 6) long, inserted near mid level of segment.

Number of setae and solenidia on leg II (femur to tarsus); 3–3–4–5(1). Femur II with setae d near base and l’ and v” near mid length of segment. Genu II with seta v’ shorter than basally located l’ and l”. Tibia II with v” shorter than v’, seta d longest on segment, but setae l’ longer than v’ or v”; all setae inserted in distal half of tibia II; Tarsus II with a clavate, 6 (5–6, 6) long, located 1/3 basal part of tarsus II. Seta tc’ longer than seta tc”.

Number of setae and solenidia on leg III (femur to tarsus): 1–3–4–3. Femur III with femoral v inserted 1/3 upper part of segment. Genu III with setae v’ and pair l’, which are shorter than former. Tibia III with v’ about twice as long as l’; all setae inserted near mid length of tibia III. Tarsus III with tc” more than twice as long as pv’.

Number of setae and solenidia on leg IV (femur to tarsus): 1+2–1(1)–3. Femorogenu IV with l”G slender, 13 (10–15, 10), longer than v’F 7 (6–8, 6) and genual v’G 9 (8–10, 8). Tibia with seta v’Ti stout, 16 (15–17, 16) and a solenidion 7 (7–8, 7) long, curved. Tarsus with setae tc”, pv” and u’ minute. Terminal claw unguiform.

Types. Holotype, adult female, allotype male, paratypes four females, five males and three larvae. New Zealand, Auckland Island, Carnley Harbour, Tagua Bay , 18 February 1973, J. S. Dugdale, on Poa litorosa ; all types deposited in the New Zealand Arthropod Collection, Auckland.

Etymology. The specific name is Latin (branch), alluding to the branched bothridial setae (sc 1).

Remarks. This species is similar to Steneotarsonemus (Neosteneotarsonemus) trisetus as coxal setae 2a are located well behind inner end of apodeme 2, but in the former the c 2 setae are shorter than setae c 1, whereas setae c 2 in the new species are longer than setae c 1 in female. The bothridial setae are branched in the new species, but are simple in S. trisetus .

Variation. In the female, normally there is one spur plus one solenidion near basal 1/3 of tarsus II, but in one paratype female, there are two solenidia near basal 1/3 of tarsus II (i.e. the spur becomes a solenidion).

Figures

FIGURE 1. Steneotarsonemus (Neosteneotarsonemus) ramus sp. nov. (dorsal view of female).

FIGURE 2. Steneotarsonemus (Neosteneotarsonemus) ramus sp. nov. (ventral view of female).

FIGURE 3–6. Steneotarsonemus (Neosteneotarsonemus) ramus sp. nov. (female legs I–IV). 3, leg I and enlarged tibiotarsus; 4, leg II and enlarged tarsus; 5, leg III; 6, leg IV.

FIGURE 7. Steneotarsonemus (Neosteneotarsonemus) ramus sp. nov. (dorsal view of male).

FIGURE 8. Steneotarsonemus (Neosteneotarsonemus) ramus sp. nov. (ventral view of male).

FIGURE 9–12. Steneotarsonemus (Neosteneotarsonemus) ramus sp. nov. (male legs I–IV). 9, leg I and enlarged tibia and tarsus; 10, leg II; 11 leg III; 12 leg IV.