Ologamasus lucasi, Santos, Jandir C., Castilho, Raphael C., Silva, Edmilson S. & De Moraes, Gilberto J., 2015

Santos, Jandir C., Castilho, Raphael C., Silva, Edmilson S. & De Moraes, Gilberto J., 2015, Two new species of Ologamasus (Acari: Mesostigmata: Ologamasidae) from Brazil with a key to the world species of the genus, Zootaxa 4058 (2), pp. 267-277 : 268-272

Ologamasus lucasi n. sp.

Material examined. Holotype female, four paratype females and five paratype males from litter at the base of Mimosa sp. ( Fabaceae ) at Olho d'Água das Flores (9°31'54''S and 73°16'76"W), State of Alagoas, Brazil, 15 November 2011. All types collected by J.C. Santos and deposited at Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “Luiz de Queiroz” ( ESALQ), Universidade de São Paulo ( USP), Piracicaba, State of São Paulo, Brazil.

Adult female ( Figs 1–8 ) (five specimens measured).

Gnathosoma. Fixed cheliceral digit 95 (92–100) long, with six teeth in addition to apical tooth and a setiform pilus dentilis ( Fig. 1 ); movable digit 89 (80–90) long with three teeth in addition to apical tooth; antiaxial and dorsal lyrifissures as well as dorsal seta distinct. Arthrodial process of chelicera shaped as a short coronet-like fringe. Number of setae on palp (trochanter to tarsus): 2-5-6-14 -15; apotele 3-tined; setae aciculate and smooth, except al 1 of palp genu, rayed ( Fig. 2 ). Epistome with anteromedian extension acuminate and variously serrate ( Fig. 3 ). Deutosternum delimited by lateral lines; with eight transverse lines; most distal line smooth and each of the other lines with 6–10 denticles; first, second and fifth to seventh lines with 6–9 additional denticles laterad of each lateral deutosternal line ( Fig. 4 ). Internal malae separated from each other and with external margin fimbriate. Corniculus horn-like, about twice as long as its basal width. Seta h 3 about in longitudinal line with h 1, mediad and slightly anterior to h 2. Measurements of setae: h 1 46 (42–50), h 2 34 (33–35), h 3 47 (45–50), sc 35 (36–37); all aciculate and smooth.

Dorsal idiosoma ( Fig. 5 ). Idiosoma 724 (707–737) long and 490 (470–500) wide at widest point. Podonotal and opisthonotal shields fused, completely covering dorsum of idiosoma and extending ventrolaterally; imbricate and with tiny shallow pits posterior to z 5 and in the anterolateral region of the dorsal shield posterior to z 2 ( Fig. 8 ). Podonotal region with 20 pairs of setae (z 4, s 1, s 4 and r 1 absent) and four pairs of distinguishable lyrifissures. Opisthonotal region with 18 pairs of setae (Z 4 and R 5 absent), seven pairs of lyrifissures and one pair of pores (close to R 3). Measurements of setae: j 1 51 (48–55), j 2 63 (62–65), j 3 72 (68–75), j 4 75, j 5 60 (57–63), j 6 62 (58– 64), z 1 25 (22–30), z 2 34 (32–37), z 3 55 (53–57), z 5 72 (70–75), z 6 76 (73–77), s 2 18 (17–20), s 3 37 (35–39), s 5 72 (69–75), s 6 92 (88–97), r 2 32 (30–33), r 3 94 (92–97), r 4 25 (23-27), r 5 33 (28–35), r 6 37 (35–40), J 1 68 (65–70), J 2 74 (70–77), J 3 78 (75–80), J 4 89 (88–92), J 5 87 (85–90), Z 1 90 (88–92), Z 2 93 (90–98), Z 3 98 (95–100), Z 5 98 (95–100), S 1 66 (65–70), S 2 87 (85–90), S 3 86 (80–90), S 4 95 (88–100), S 5 91 (88–95), R 1 24 (23–25), R 2 26 (25– 27), R 3 26 (25–27), R 4 33 (30–35); all aciculate and smooth.

Ventral idiosoma ( Fig. 6 ). Base of tritosternum 31 (30–31) long and 14 (12–15) wide proximally ( Fig. 7 ); laciniae 87 long, totally separated and pilose; inserted between a pair of reticulate presternal platelets. Sternal shield reticulate in anterior third and with longitudinal and parallel striae elsewhere; 117 (105–122) long at midline and 205 (200–210) wide between coxae II and III; posterior margin slightly concave; with four pairs of setae and four pairs of lyrifissures. Endopodal plate II-III incorporated into sternal shield, plate between coxae III and IV represented by a broad plate. Genital shield longitudinally striate; about as long as wide; posterior margin truncate, in line with posterior margin of coxa IV; distance st 5– st 5 129 (125–137). Unsclerotised integument posterolaterad of st 5 with a pair of lyrifissures (iv 5). Ventrianal shield imbricate, with tiny shallow pits similar to those of dorsal shield; 369 (343–387) long at mid-line and 433 (413–450) wide at widest level, fused posterolaterally with dorsal shield; with eight pairs of setae (Jv 1– Jv 5 and Zv 1– Zv 3) in addition to circumanal setae; with four pairs of lyrifissures and one pair of pores. Unsclerotised strip of integument separating dorsal from ventrianal shield almost reaching Jv 5. Peritreme extending anteriorly to median region of coxa I (level of seta s 2). Peritrematic plate fused anteriorly with dorsal shield and posteriorly to exopodal plate near coxa IV; with a pair of lyrifissures and a pore posterior to stigma. Exopodal plate in three fragments, an oval fragment between coxae I and II, an irregular fragment between coxae II and III, and a sub-triangular fragment between coxae III and IV. Metapodal platelet indistinguishable. Measurements of setae: st 1 28 (27–28), st 2 29 (27–30), st 3 28 (27–28), st 4 29 (28–30), st 5 32 (30–35), Jv 1 39 (37–42), Jv 2 47 (42–50), Jv 3 50 (49–50), Jv 4 61 (60–62), Jv 5 86 (82–87), Zv 1 43 (40–50), Zv 2 51 (50–55), Zv 3 63 (62–67), para-anal 51 (50–52), post-anal 47 (40–55); all aciculate and smooth.

Spermathecal apparatus: indistinguishable.

Legs. Lengths: I: 664 (648–687), II: 483 (475–500), III: 460 (445–467); IV: 627 (612–637). Chaetotaxy: I: coxa 0 0/2, 0/0 0, trochanter 1 0/1, 1/2 1, femur 2 5/4 2, genu 2 3/2, 3/1 2, tibia 2 3/2, 3/2 2; II: coxa 0 0/1, 0/1 0, trochanter 1 0/3 1, femur 2 3/1,2/2 1, genu 2 3/1, 2/1 2, tibia 2 2/1, 2/1 2; III: coxa 0 0/1, 0/1 0, trochanter 1 1/1, 0/ 2 1, femur 1 2/1, 2/0 0, genu 2 2/1, 2/1 1, tibia 2 1/1, 2/1 1; IV: coxa 0 0/1, 0/0 0, trochanter 1 1/2, 0/1 0, femur 2 1/ 0, 1/0 2, genu 2 2/1, 2/1 2, tibia 2 1/1, 3/1 2; tarsi II-IV: 18 setae each. Setae aciculate and smooth. All legs with pretarsi; median section of pulvilli of legs I–IV rounded, with an elongate ambulacral stalk and a pair of prominent claws; pretarsus I about half as long as other pretarsi.

Adult male ( Figs 9–12 ) (five specimens measured).

Gnathosoma. Fixed cheliceral digit 81 (75–87) long, with five teeth in addition to apical tooth and a setiform pilus dentilis ( Fig. 9 ); movable digit 79 (79–80) long, with one tooth in addition to apical tooth; spermatodactyl 68 (62–70) long, about uniformly arched dorsally; antiaxial and dorsal lyrifissures as well as dorsal seta distinct. Epistome with an anteromedian extension acuminate and variously serrate ( Fig. 10 ). Arthrodial process of chelicera, palp chaetotaxy, apotele, deutosternum, internal mala, corniculus and position of hypostomal setae as in adult female. Measurements of setae: h 1 48 (45–50), h 2 45, h 3 58 (53–60), sc 30 (28–32); shape of setae as in adult female.

Dorsal idiosoma. Idiosoma 720 (700–756) long and 483 (463–487) wide at widest point; dorsal shield similar to that of adult female. Measurements of setae: j 1 46 (40–52), j 2 70 (68–75), j 3 76 (73–80), j 4 74 (73–77), j 5 54 (53–55), j 6 64 (63–67), z 1 26 (25–27), z 2 34 (33–35), z 3 50 (47–53), z 5 73 (70–75), z 6 70 (68–72), s 2 25, s 3 31 (30-35), s 5 75 (70–77), s 6 92 (88–100), r 2 25, r 3 87 (83–90), r 4 22 (20-25), r 5 32 (30–37), r 6 33 (28–37), J 1 67 (62–75), J 2 78 (78–80), J 3 81 (75–87), J 4 88 (83–97), J 5 79 (75–80), Z 1 89 (87–92), Z 2 89 (87–92), Z 3 92 (88– 95), Z 5 90 (88–92), S 1 52 (51–52), S 2 79 (70–87), S 3 87 (85–90), S 4 85 (78–87), S 5 86 (83–90), R 1 25, R 2 25, R 3 25, R 4 25; shape of setae as in adult female.

Ventral idiosoma ( Fig. 11 ). Base of tritosternum 33 (33–34) long and 16 (15–17) wide proximally; laciniae 83 long, totally separated and pilose; inserted between a pair of reticulate presternal platelets. Sternogenital shield longitudinally striate; 230 (225–235) long at mid-line and 205 (202–208) wide between coxae II and III; with five pairs of setae and three pairs of lyrifissures; posterior margin truncate and slightly anterior to posterior margin of coxa IV. Ventrianal shield imbricate, with tiny shallow pits as in adult female; 374 (352–385) long at mid-line and 455 (440–450) wide at widest point, fused with peritrematic plate and posterolaterally with dorsal shield; with eight pairs of setae (Jv 1– Jv 5 and Zv 1– Zv 3) in addition to circumanal setae and four pairs of lyrifissures. Peritreme extending anteriorly almost to median region of coxa I (level of seta s 2). Peritrematic plate fused anterolaterally to dorsal shield and posteriorly to exopodal plate near coxa IV and to ventrianal shield; with a pair of lyrifissures and a pore posterior to stigma. Exopodal plate fragmented as in adult female. Measurements of setae: st 1 38 (35–40), st 2 38 (33–42), st 3 25 (25–26), st 4 31 (30–32), st 5 31 (29–37), Jv 1 45 (43–47), Jv 2 49 (48–50), Jv 3 49 (47–50), Jv 4 52 (50–57), Jv 5 73 (70–75), Zv 1 46 (45–47), Zv 2 50 (47–50), Zv 3 43 (40–50), para-anal 47 (43–50), post-anal 51 (43–55); shape of setae as in adult female.

Legs. Lengths: I: 681 (645–725); II: 478 (470–487); III: 460 (437–470); IV: 654 (638–675). Numbers of setae of leg segments as in adult female. Shape of setae as in adult female, except for the stout av 1 and a spur-like structure occupying same position as av 2 of femur II and one ventral spur-like structure on each of genu and tibia II ( Fig. 12 ). All legs with pretarsi similar to those of adult female.

Etymology. The name lucasi is a posthumous tribute to Lucas Lucchini Faquini, a trainee at the Acarology Laboratory of Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo.

Remarks. Ologamasus lucasi is most similar to Ologamasus simplicior ( Berlese, 1914) , but females of the latter species have the podonotal region of dorsal idiosomal shield with 21 pairs of setae (s 1, s 4 and r 1 absent); opisthonotal region of dorsal idiosomal shield with 20 pairs of setae (Z 4 and R 5 present); setae Jv 3 and Zv 2 respectively at least as long as distances between their bases and bases of Jv 4 and Zv 3.

Figures

FIGURE 8. Ologamasus lucasi n. sp. Female. Scanning electronic micrograph of dorsal shield. Scale bar = 10 µm.

FIGURES 1 – 7. Ologamasus lucasi n. sp. Female. 1. Lateral (antiaxial) view of chelicera; 2. Palp trochanter; 3. Epistome; 4. Hypostome; 5. Dorsal idiosoma; 6. Ventral idiosoma; 7. Tritosternum. Lyrifissures enlarged for improved visibility.

FIGURES 9 – 12. Ologamasus lucasi n. sp. Male. 9. Lateral (antiaxial) view of chelicera; 10 Epistome; 11. Ventral idiosoma; 12. Anterolateral view of femur (fe), genu (ge) and tibia (ti) of leg II. Lyrifissures enlarged for improved visibility.