Ceratotarsonemus amazonicus Rezende, Lofego & Ochoa, 2018

Rezende, José Marcos, Lofego, Antonio Carlos, Gulbronson, Connor, Bauchan, Gary & Ochoa, Ronald, 2018, Review of the genus Ceratotarsonemus De Leon, 1956 (Acari: Prostigmata: Tarsonemidae), with description of a new species from the Amazon Forest, Zootaxa 4483 (2), pp. 271-294 : 275-286

Ceratotarsonemus amazonicus Rezende, Lofego & Ochoa sp. nov.

( Figs. 4–16 )

Diagnosis. Female: Pharyngeal pump about 1/2 gnathosomal width. Palpal length about 1/2 gnathosomal length. Prodorsal shield with hexagonal reticulation posteriorly. Tergite C with inverted U-shaped reticulation dorsally, which has four rows of reticula. All dorsal setae coarsely barbed, except for bothridial setae sc1. Vertical setae v1 about ½ length scapular setae sc2 on prodorsum. Setae c1 distinctly longer than c2 on tergite C. Setae c2 and e long (~ 65 and 80 µm, respectively). Ventral surface of propodosoma with prosternal apodeme complete, extending from apodemes 1 to sejugal apodeme.

Description. Female: holotype and four paratypes measured.

Gnathosoma ( Figs. 4 and 5 A-B): capsule subquadrate in outline, 28 (22–28) long (~ 0.2x LI), 19 (18–21) wide (~ 0.2x WI). Palpi 11 (11–13) long (~ 0.4x LG), 3 wide (~ 0.2x WG), with small rounded processes apically, two minute setae. Pharynx fusiform, 15 (13–15) long (~ 0.5x LGC), 6 wide (6–7) (~ 0.3x WG), with external walls and musculature well developed. Cheliceral stylets short, subtriangular, attached to defined basal levers. Gnathosomal setae: dgs 10 (10–12) long (~ 0.4x LG), setiform, smooth. Setae vgs 7 (5–7) long (~ 0.3x LG), setiform, smooth. Setae pp absent. Relative length of gnathosomal setae (dgs: vgs): 1: 0.7.

Idiosoma, dorsal plates and stigmata ( Figs. 5C and 6–9 ): idiosoma 172 (159–172) long (~ 1.9x WI), 95 (95–103) wide at level of c2 (0.6x LI). PrS 54 (48–56) long (~ 0.3x LI), 62 (60–65) wide (~ 0.6x WI) at stigmata level, hoodlike, covering gnathosoma, with convex posterior margin, reticulated. Prodorsomedial apodeme absent. Stigmata openings located closely anterior to scapular setae sc1, on inconspicuous projections anterolaterally. Tracheal tubes hardly discernible. Postatrial sacs absent or not visible. Tergite C 44 (40–48) long (~ 0.3x LI), 95 (95–103) wide at level of c2, with concave posterior edge, reticulated, covered by roulade-shaped cerotegument. D 65 (62–68) long (~ 0.4x LI), 75 (73–78) wide at level of d (~ 0.8x WI), with distinctly convex posterior margin. EF 20 (18–20) long (~ 0.1x LI), 50 (48–50) wide at level of e (~ 0.5x WI), with slightly convex posterior edge. H 10 long (~ 0.07x LI), 25 (23–25) wide at level of h (~ 0.2x WI), with convex margin. PrS and C covered medially with reticulate turtle-shell-like ornamentation.

Dorsal setae, pits and cupules ( Figs. 5D , 6 , 7 and 10 ): All dorsal setae coarsely barbed, except for bothridial setae sc1. v1 72 (64–72) (~ 3.5x DBB v1); sensilli sc1 16 (13–16) (~ 0.5x DBB sc1), capitate with tiny spines; sc2 102 (94–102) (~ 2x DBB sc2), inserted anterolaterally to sc1; c1 85 (80–85) (~ 1.4x DBB c1), inserted closely to margin of tergite D; c2 64 (64–70) (~ 1x DBB c2); d 106 (105–110) (~ 2.5x DBB d); e 74 (74–86) (~ 2.5x DBB e); f 31 (29–34) (~ 3x DBB f); h 24 (23–26) (~ 1.2x DBB h). Relative length of dorsal setae (mean values— v1: sc1: sc2: c1: c2: d: e: f: h): 1: 0.2: 1.4: 1.2: 0.9: 1.5: 1: 0.5: 0.4. Distance between dorsal setae: v1–v1 20 (20–21); sc1– sc1 30 (29–30); sc2–sc2 50 (50–52); v1 –sc2 22 (20–22); c1–c1 60; c2–c2 65 (62–65); c1–c2 18 (16–19); d–d 40 (38–42); e–e 30 (28–32); f–f 10 (10–12); e–f 13 (12–14); h–h 20 (18–20). Relative distances between setae bases (mean values— v1–v1: sc1–sc1: sc2–sc2: v1 –sc2: c1–c1: c2–c2: c1–c2: d–d: e–e: f–f: e–f: h–h): 1: 1.5: 2.5: 1.1: 3: 3.4: 0.9: 2: 1.5: 0.5: 0.6: 1. Pits v2 located nearly in oblique line between setae sc2 and v1 on either side, nearly anteriad of sc1. Diameter and position of cupules: ia 4 anterolaterally to setae d; im 3 anterolaterally to setae e; ih difficult to discern.

Ventral plates ( Figs. 11–14 ): PrP 40 (38–41) long (~ 0.25x LI), 72 (70–72) wide at level of sejugal apodeme (~ 0.8x WI), anterior edge between apodemes 1 distinctly concave, lateral ridges between trochanters I and II convex. MtP 47 (46–47) long (~ 0.4x LI), 90 wide at level of setae 3a (~ 1x WI), anterior margin nearly straight, posterior margin undulate between trochanters III and IV. Lateral extensions of metapodosomal ventral plate extend over tergites D and EF laterally. Tegula 3 long (~ 0.02x LI), 18 (16–18) wide (~ 0.2x WI), margin convex. Ag 40 (38–40) long (~ 0.25x LI), without setae. Ps 9 long (~ 0.6x LI), 16 wide at level of setae ps (~ 0.2x WI), posterior margin slightly concave. Ventral extensions of coxisternal plates IV slightly overlapped medially behind tegula.

Ventral setae and coxal pits ( Fig. 11 ): setae 1a 8 (7–8) (~ 0.8x DBB 1a), setiform, smooth, near posteromedial margin of apodemes 1; 2a 8 (8–10) (~ 0.3x DBB 2a), setiform, smooth, near posteromedial margin of apodemes 2; 3a 7 (6–7) (~ 0.5x DBB 3a), setiform, smooth, near bifurcation of poststernal apodeme; 3b 8 (7–9) (~ 0.3x DBB 3b), setiform, near posterior margin of apodemes 4; ps 14 (12–14) (~ 0.9x DBB ps), setiform, serrate. Relative length of ventral setae (1a: 2a: 3a: 3b: ps): 1: 1.0: 0.9: 1.0: 1.9. Distance between ventral setae: 1a–1a 10 (9–10); 2a–2a 23 (22–24); 3a–3a 13 (13–14); 3b–3b 25 (24–26); ps–ps 16 (16–17). Relative distance of ventral setae bases (mean values— 1a–1a: 2a–2a: 3a–3a: 3b–3b: ps–ps): 1: 2.3: 1.3: 2.5: 1.6. Coxal pits: 1b located well laterad of setae 1a; 2b located well laterad of setae 2a.

Ventral apodemes ( Figs. 11–14 ): Apodemes 1 well defined, joined with anterior end of prosternal apodeme. Apodemes 2 not joined to prosternal apodeme. Prosternal apodeme well defined, extending from junction with apodeme 1 to sejugal apodeme. Sejugal apodeme well defined, uninterrupted. Apodemes 3 extending diagonally from proximity of base of seta 3a to (but not laterally beyond) anterior margin of trochanters III, with a median bent. Apodemes 4 extending diagonally, from posterior third of poststernal apodeme nearly to base of seta 3b. Poststernal apodeme bifurcated anteriorly.

Legs ( Figs. 15–16 ): length (measured from trochanter to tarsus): leg I 45 (45–49) (~ 0.3x LI); leg II 49 (43–49) (~ 0.3x LI); leg III 86 (80–86) (~ 0.5x LI); leg IV 28 (27–28) (~ 0.2x LI). Relative lengths of legs (mean values— I:II:III:IV): 1: 1.0: 2.0: 0.5. Free leg segments: leg I: femur I 14 (13–14) long (~ 0.3x LLI), 10 (9–10) wide (~ 0.6x LFeI); genu I 8 (8–9) long (~ 0.2x LLI), 8 (7–8) wide (~ 1.0 x LGeI); tibiotarsus I 15 (15–17) long (~ 0.3x LLI), 5 wide (0.3x LTbTaI). Leg II: femur II 12 (12–14) long (~ 0.25x LLII), 11 (11–13) wide (~ 1.0x LFeII), with a small concavity; genu II 7 (7–8) long (~ 0.2x LLII), 8 (8–9) wide (~ 1.1x LGeII); tibia II 7 (7–8) long (~ 0.2x LLII), 6 (6– 7) wide (~ 1.0x LTbII); tarsus II 7 long (~ 0.2x LLII), 5 (5–6) wide (~ 0.8x LTaII). Leg III: femorogenu III 16 (16– 18) long (~ 0.2x LLIII), 6 (6–8) wide (~ 0.4x LFeGeIII); tibia III 17 (16–18) long (~ 0.2x LLIII), 6 (6–7) wide (~ 0.3x LTbIII); tarsus III 10 (10–12) long (~ 0.1x LLIII), 4 (4–6) wide (~ 0.4x LTaIII). Leg IV: femorogenu IV 15 (15–16) long (~ 0.5x LLIV), 3 wide (~ 0.2x LFeGeIV); tibiotarsus IV 8 (8–9) long (~ 0.3x LLIV), 3 wide (~ 0.3x LTbTaIV). Trochanters IV separated by interval of ~ 3x their widths. Ambulacra of legs I-III: ambulacrum I with minute empodial pad bearing one short claw curved distally; ambulacra II-III with empodial pads and two symmetrically paired claws.

Leg chaetotaxy ( Figs. 15–16 ): Number of setae (solenidia in parentheses) on femur, genu, tibia and tarsus, respectively: leg I: 3–4–6(1 φ)+7(1 ω); leg II: 3–3–4–4(1 ω); leg III: 1+1–4–4; leg IV:1+1–1+1. Setae present on each leg segment: Leg I: femur I: d 6 (5–6) (~ 0.5x LFeI) serrate, l' 8 (8–9) (~ 0.6x LFeI) smooth, v" 6 (~ 0.5x LFeI) smooth; genu I: l' 9 (8–9) (~ 1.0x LGeI) serrate, l" 6 (5–6) (~ 0.7x LGeI) serrate, v' 5 (4–5) (~ 0.6x LGeI) smooth, v" 7 (7–8) (~ 0.9x LGeI) smooth; tibiotarsus I: (setae): d 28 (28–31) (~ 1.9x LTbTaI) serrate, l' 17 (17–19) (~ 1.1x LTbTaI) serrate, l" 12 (12–13) (~ 0.8x LTbTaI) serrate, v' 13 (13–14) (~ 0.9x LTbTaI) serrate, v" 16 (16–17) (~ 1.1x LTbTaI) serrate, k 5 (~ 0.3x LTbTaI), pv' 6 (~ 0.3x LTbTaI) smooth, pv" 8 (8–9) (~ 0.6x LTbTaI) smooth, s 2 (~ 0.1x LTbTaI) spine-like, (eupathidia): p' 11 (~ 0.7x LTbTaI), p" 17 (~ 1.1x LTbTaI), tc' 16 (16–17) (~ 1.1x LTbTaI), tc" 18 (17–18) (~ 1.2x LTbTaI), (solenidia): cluster incomplete, inserted at same level: solenidion φ1 3 (~ 0.2x LTbTaI) slender and clavate; solenidion ω 7 (6–7) (~ 0.4x LTbTaI), fusiform. Leg II: femur II: d 6 (5–6) (~ 0.5x LFeII) serrate, l' 7 (7–8) (~ 0.5x LFeII) smooth, v" 14 (13–15) (~ 1.2x LFeII) smooth; genu II: l' 13 (12–13) (~ 1.9x LGeII) serrate, l" 6 (6–7) (~ 1.0x LGeII) serrate, v' 15 (14–15) (~ 2.1x LGeII) serrate; tibia II: d 13 (12–13) (~ 1.9x LTbII) serrate, l' 13 (13–14) (~ 1.9x LTbII) serrate, v' 14 (~ 2.0x LTbII) serrate, v" 14 (14–16) (~ 2.0x LTbII) serrate; tarsus II: tc' 10 (9–10) (~ 1.2x LTaII) smooth, tc" 9 (~ 1.1x LTaII) serrate, pv' 14 (13–14) (~ 2.0x LTaII) serrate, u' 3 (~ 0.4x LTaII) spine-like, (solenidia): solenidion ω 6 (~ 0.4x LTaII) proximally inserted, stout, fusiform. Leg III: femorogenu III: v' F 7 (~ 0.4x LFeGeIII) smooth, l' G 10 (9–10) (~ 0.6x LFeGeIII) smooth; tibia III: d 10 (9–10) (~ 0.6x LTbIII) smooth, l' 14 (14–15) (~ 0.8x LTbIII) serrate, v' 9 (9–10) (~ 0.5x LTbIII) serrate, v" 9 (9–10) (~ 0.5x LTbIII) smooth; tarsus III: tc' 13 (12–13) (~ 1.3x LTaIII) serrate, tc" 18 (18–20) (~ 1.8x LTaIII) serrate, pv' 12 (11–12) (~ 1.2x LTaIII) smooth, u' 3 (~ 0.2x LTaIII) spine-like. Leg IV: femorogenu IV: v' F 8 (7–9) (~ 0.5x LFeGeIV) smooth, v' G 9 (9–11) (~ 0.6x LFeGeIV) smooth; tibiotarsus IV: v' Ti 22 (21–24) (~ 2.9x LTbTaIV) falcate, tc" 35 (32–37) (~ 3.5x LTbTaIV) smooth.

Male and Larva: unknown.

Type material: holotype and 19 paratypes on Psychotira sp. ( Rubiaceae ), four paratypes on Bignoniaceae sp. and one paratype on Annonaceae sp., 58°14ʹW 9°51ʹS, Cotriguaçú, State of Mato Grosso, Brazil, 01/II/2015, A. C. Lofego, F. S. R. Amaral & J. M. Rezende. Holotype and 15 paratypes deposited at DZSJRP; 10 paratypes deposited at USNM.

Remarks. Females of Ceratotarsonemus amazonicus sp. nov. are most similar to those of Ceratotarsonemus alas Ochoa & Vargas in having tergite C with reticulation forming a broad inverted U-shape, the reticula wider than long, identical lengths of dorsal setae sc1 and f, and the sejugal apodeme well defined along its whole extension. Female C. amazonicus , sp. nov. are distinguished by the length of their dorsal setae c2 and e (~ 30% longer than female C. alas , for both pairs of setae) and by the number of reticula rows on tergite C (four rows observed in C. amazonicus sp. nov. whereas just two in C. alas ).

Etymology. The species is named amazonicus indicating the biome where the species has been found.

Figures

FIGURE 4. Ceratotarsonemus amazonicus, sp. nov.: A–D: different focal planes (from dorsal to ventral view) of the gnathosoma under the differential interference contrast (DIC) microscopy (squared areas in A–B: dorsal apices of cheliceral levers).

FIGURE 5. Ceratotarsonemus amazonicus, sp. nov.: Gnathosoma: A—ventral view; B—detail of the palps and tips of chelicerae (squared). Stigmata: C—lateral view (squared); D—ventral view, showing also the bothridial setae sc1.

FIGURE 6. Ceratotarsonemus amazonicus, sp. nov.: dorsal surface.

FIGURE 7. Ceratotarsonemus amazonicus, sp. nov.: dorsal surface: A—phase contrast; B—differential interference contrast; C—low temperature scanning electron microscopy.

FIGURE 8. Ceratotarsonemus amazonicus, sp. nov.: ornamentation on dorsal surface: A—differential interference contrast; B—low temperature scanning electron microscopy.

FIGURE 9. Ceratotarsonemus amazonicus, sp. nov.: details of wax-like substance over the dorsum under low temperature scanning electron microscopy (LT-SEM).

FIGURE 10. Ceratotarsonemus amazonicus, sp. nov.: details of dorsal setae.

FIGURE 11. Ceratotarsonemus amazonicus, sp. nov.: ventral surface.

FIGURE 12. Ceratotarsonemus amazonicus, sp. nov.: ventral surface: A—phase contrast; B—differential interference contrast; C—low temperature scanning electron microscopy.

FIGURE 13. Ceratotarsonemus amazonicus, sp. nov.: details of the internal structures under the differential interference contrast (DIC) microscopy: A—gastric caecae; B—seminal receptacle and duct leading to ovary.

FIGURE 14. Ceratotarsonemus amazonicus, sp. nov.: A–B: details of the external and internal structures under confocal laser scanning microscopy (CLSM) microscopy.

FIGURE 15. Ceratotarsonemus amazonicus, sp. nov.: A—leg I; B—leg II; C—leg III; D—leg IV.

FIGURE 16. Ceratotarsonemus amazonicus, sp. nov.: details of the legs: A—leg I; B—leg II; C—leg III; D—leg IV.