Rykellus anibali, 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 Rykellus (Acari: Mesostigmata: Ologamasidae) from Brazil and a key to the world species of the genus, Zootaxa 3926 (1), pp. 111-121 : 113-115

Rykellus anibali n. sp.

Material examined. From "Polo Regional Vale do Ribeira Pariquera-Açu" (24°36’41’’S; 47°53’23’’W), State of São Paulo: holotype female from the rhizosphere of Attalea dubia Mart. (Arecaceae) , 20 July 1999; two paratype females from litter at bases of Astrocaryum aculeatissimum Schott. (Arecaceae) and Bactris setosa Mart. (Arecaceae) , 16 January 2000; one paratype female from litter at base of Euterpe edulis Mart. (Arecaceae) , 18 April 2000; two paratype males from litter at base of A. dubia , 11 July 2000; two paratype females and three paratype males from litter at base of A. aculeatissimum , A. dubia , B. setosa and E. edulis , 12 October 2000; one paratype male from litter at base of E. edulis , 5 April 2001; one paratype male from litter at base of E. edulis , 10 December 2001. From margin of road between Pariquera-Açu and Cananéia (SP 226), state of São Paulo: one paratype female from litter at base of Geonoma schottiana Mart. (Arecaceae) , 12 July 2000; one paratype male from litter at base of G. schottiana , 11 October 2000; one paratype female from litter at base of E. edulis , 5 April 2001.

All types were collected by A.R. Oliveira. Holotype, four paratype females and five paratypes males are 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; three paratypes females and three paratypes males are deposited at Departamento de Fitossanidade, Faculdade de Ciências Agrárias e Veterinárias ( FCAV), Universidade Estadual Paulista ( UNESP), Jaboticabal, State of São Paulo, Brazil.

Adult female ( Figs 1–8 ) (five specimens measured). All setae aciculate and smooth.

Gnathosoma. Fixed cheliceral digit 55 (53–58) long, with five teeth in addition to apical tooth and a setiform pilus dentilis, dorsal lyrifissure and dorsal seta distinct, antiaxial lyrifissure not visible ( Fig. 1 ); movable cheliceral digit 56 (55–58) long, with three teeth in addition to apical tooth. Arthrodial process of chelicera shaped as a short coronet-like fringe. Number of setae on palp (trocanter to tarsus): 2-5-6-14 -15; apotele 3-tined ( Fig. 2 ); setae al 1 and al 2 of palp genu spatulate and smooth ( Fig. 3 ). Epistome with an anteromedian extension that is wider basally and rounded distally, flanked by a pair of stout and distally rounded anterolateral projections, shorter than the anteromedian extension ( Fig. 4 ). Deutosternal denticles in nine transverse rows contained by deutosternal lateral lines, which are about parallel to each other along the five distal rows of denticles and divergent posteriorly; each row with seven (most anterior row) to 14 (most posterior row) denticles; first, fourth and sixth-ninth rows continuing as smooth lines outside of lateral lines ( Fig. 5 ). 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, mesad of and slightly posterior to h 2. Measurements of setae: h 1 27 (23–31), h 2 22 (21–23), h 3 21 (20–23), sc 22 (21–23).

Dorsal idiosoma ( Fig. 6 ). Idiosoma 384 (378–390) long and 288 (285–290) wide at widest point. Podonotal and opisthonotal shields fused, completely covering idiosoma and extending to its ventrolateral regions, smooth; line of fusion v-shaped. Podonotal region with 22 pairs of setae (s 1 and r 1 absent), one pair of distinguishable lyrifissures and four pairs of pores (including a ventrolateral pair next to region between coxae II and III). Unsclerotised integument along lateral margins of podonotal region without setae (visible in the ventrolateral regions). Opisthonotal region with 22 pairs of setae and one pair of distinguishable lyrifissures and one pair of pores. Unsclerotised integument along lateral margins of opisthonotal region with two pairs of setae (R 1 and R 2) (visible in the ventrolateral regions). Measurements of setae: j 1 11 (10–11), j 2 32 (32–33), j 3 31 (30–32), j 4 29 (28–30), j 5 20 (20–21), j 6 21 (20–23), z 1 9 (8–10), z 2 29 (27–32), z 3 28 (27–30), z 4 28 (25–30), z 5 22 (20–23), z 6 23 (22–24), s 2 24 (22–26), s 3 25 (23–28), s 4 26 (26–27), s 5 25 (23–27), s 6 25 (24–26), r 2 21 (20–21), r 3 15 (15–16), r 4 17 (14–20), r 5 15 (15–16), r 6 21 (20–22), J 1 20 (19–22), J 2 19 (17–21), J 3 21 (20–22), J 4 22 (21–23), J 5 29 (28–30), Z 1 26 (25–28), Z 2 24 (22–26), Z 3 27 (25–30), Z 4 24 (23–26), Z 5 27 (26–28), S 1 24 (23–25), S 2 26 (26–27), S 3 25 (23–26), S 4 28 (27–29), S 5 23 (20–26), R 1 8 (8–9), R 2 8 (7–9), R 3 23 (21–26), R 4 23 (21–25), R 5 23 (22–23), UR 3 21 (20–22), UR 4 29 (27–30). All setae much shorter than distance between their bases and bases of respective subsequent setae.

Ventral idiosoma ( Fig. 7 ). Base of tritosternum 7 (7–8) long and 12 (13–14) wide proximally ( Fig. 8 ); laciniae 62 (62–63), separated for about 80% of their total length, pilose. A pair of presternal plates present, each with a transverse line, and a platelet between them. Sternal shield smooth; 82 (82–83) long at mid-line and 110 (106–115) wide between coxae II and III; with four pairs of setae and three pairs of lyrifissures; with a triangular process laterad of lyrifissure iv 1; not fused with section of endopodal plate behind middle of coxae III; posterior margin concave. Genital shield smooth; extending posteriorly slightly behind coxae IV; posterior margin truncate; distance between st 5– st 5 70 (69–72). Genital lyrifissures indistinguishable. A pair of elliptical platelets present posterior to and slightly mesad of coxa IV, perhaps remnants of the posterior end of endopodal or exopodal plates (more mesad than usual for metapodal platelets of other Rhodacaroidea). Ventrianal shield striate along anterior margin and next to anterolateral corners, smooth elsewhere; 225 (220–230) long at mid-line and 188 (185–190) wide at widest level; with six pairs of setae (Jv 1– Jv 3, Jv 5, Zv 1 and Zv 2) in addition to circum-anal setae, and three pairs of distinguishable lyrifissures and two pairs of pores; para-anal seta about 1.4 times as long as post-anal seta and inserted slightly anteriad of anterior margin of anal opening. Unsclerotised integument along margins of ventrianal shield with a pair of setae (Zv 3). Peritreme extending anteriorly to level of region between coxae I and II. Peritrematic shield fused antero laterally to dorsal shield, expanded near coxa IV; with a pair of lyrifissures dorsal of peritreme and at median level of coxa II and a pair posterior to stigma. Exopodal shield distinct from region between coxae I–II to median level at coxa IV, but interrupted at median level of coxa III, forming an anterior elongate plate and a posterior triangular plate. Measurements of setae: st 1 27 (25–28), st 2 21 (20–22), st 3 18 (17–20), st 4 26 (25–27), st 5 26 (25–27); Jv 1 27 (25–28), Jv 2 23 (21–25), Jv 3 32 (30–33), Jv 5 33 (31–35), Zv 1 32 (30–33), Zv 2 33 (30–35), Zv 3 24 (21–26), para–anal 18 (17–19), post–anal 12 (12–13).

Spermathecal apparatus. Not distinguishable.

Legs. Lengths: I: 403 (397–408); II: 306 (303–310); III: 251 (248–255); IV: 320 (310–330). Numbers of setae on legs I–IV: coxae: 2, 2, 2, 1; trochanters: 6, 5, 5, 5; femora: 13, 11, 6, 6; genua: 13, 11, 9, 9; tibiae: 14, 10, 8, 10; tarsi II–IV: 18, 18, 17. Pretarsi I–IV similar in shape, with an elongate ambulacral stalk, a pair of strong claws and three rounded pulvillar lobes; pretarsus I about half as long as other pretarsi.

Adult male ( Figs 9–11 ) (five specimens measured). Shape of setae as in adult female, except for two ventral spur-like setae on femur II and one ventral spur-like setae on each of genu and tibia II.

Gnathosoma. Fixed cheliceral digit 48 (48–49) long, with six teeth in addition to apical tooth and a setiform pilus dentilis ( Fig. 9 ); movable cheliceral digit 44 (42–46) long, with one tooth in addition to apical tooth; spermatodactyl 28 (28–29) long, uniformly arched; dorsal lyrifissure and dorsal seta distinct, antiaxial lyrifissure not visible. Arthrodial process of chelicera, palp chaetotaxy, apotele, epistome, deutosternum and position of hypostomal setae as in adult female. Measurements of setae: h 1 27 (25–29), h 2 20 (19–20), h 3 21 (20–21), sc 22 (20–23).

Dorsal idiosoma. Idiosoma 415 (410–420) long and 300 (290–310) wide at widest point; dorsal shield similar to that of adult female, except seta UR 4 inserted on shield or on unsclerotised integument in the lateral margins of shield. Measurements of setae: j 1 8 (7–9), j 2 27 (25–28), j 3 23 (22–25), j 4 19 (18–21), j 5 18 (17–20), j 6 17 (15–19), z 1 7 (5–8), z 2 28 (25–31), z 3 25 (21–29), z 4 25 (23–28), z 5 14 (13–15), z 6 18 (18–19), s 2 23 (21–26), s 3 18 (17–20), s 4 20 (20–21), s 5 21 (20–22), s 6 24 (21–27), r 2 20 (18–22), r 3 9 (9–10), r 4 9 (9–10), r 5 11 (10–12), r 6 10 (9–10), J 1 16 (15–18), J 2 19 (18–19), J 3 19 (18–21), J 4 20 (17–23), J 5 17 (15–18), Z 1 22 (20–24), Z 2 21 (20–22), Z 3 21 (20–22), Z 4 21 (20–23), Z 5 28 (27–28), S 1 18 (18–19), S 2 23 (20–25), S 3 24 (23–24), S 4 21 (21–22), S 5 19 (18–19), R 1 8 (7–9), R 2 8 (6–9), R 3 19 (18–19), R 4 23 (22–23), R 5 27 (26–27), UR 3 21 (18–24), UR 4 23 (22–23).

Ventral idiosoma ( Fig. 10 ). Base of tritosternum 10 (10–11) long and 14 (14–15) wide proximally; laciniae 80 (80–81), other characteristics as in adult female. A pair of presternal plates present, each with a transverse line, and a platelet between them. Sternogenital shield smooth, 111 (108–115) long and 95 (95–96) wide between coxae II and III; with five pairs of setae and three pairs of lyrifissures; posterior margin slightly concave. Ventrianal shield reticulate along anterior margin and next to anterolateral corners, smooth elsewhere; 187 (180–195) long at midline and 171 (167–175) wide at widest point; with seven pairs of setae (Jv 1– Jv 3, Jv 5 and Zv 1– Zv 3) in addition to circum-anal setae and two pairs of distinguishable lyrifissures; para-anal seta about 1.4 times as long as post-anal seta and inserted slightly anteriad of anterior margin of anal opening. Peritreme, peritrematic and exopodal shields as in adult female, except absence of a pair of elliptical platelets present posterior to and slightly mesad of coxa IV. Measurements of setae: st 1 23 (20–26), st 2 23 (21–25), st 3 18 (18–19), st 4 21 (20–21), st 5 23 (20–25), Jv 1 23 (21–24), Jv 2 22 (21–23), Jv 3 27 (24–30), Jv 5 33 (31–35), Zv 1 25 (24–26), Zv 2 29 (27–31), Zv 3 17 (15–20), para–anal 15 (14–16), post–anal 11 (10–11).

Legs. Lengths: I: 362 (355–370); II: 270 (265–275); III: 220 (211–230); IV: 290 (285–295). Numbers of setae of leg segments similar to those of adult female. With two ventral spur-like setae on femur II (occupying same position as setae av 1 and av 2 of female) and one ventral spur-like structure on each of genu and tibia II (occupying respectively same position as setae av 2 of female) ( Fig. 11 ). All legs with pretarsi similar to those of adult female.

Etymology. The name anibali is used in honour of Professor Anibal Ramadan Oliveira of Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil, collector of the type specimens of this species.

Remarks. The following characteristics distinguish Rykellus anibali n. sp from all the other Rykellus species: epistome without extensions laterad of anteromedian extension; sternal shield fused with section of endopodal plate near coxae III and IV; and peritrematic, exopodal and metapodal shields fused in Rykellus darglensis ( Ryke, 1962) and Rykellus nkandhlaensis ( Ryke, 1962) . Podonotal and opisthonotal regions with 19–20 and 16–17 pairs of setae, respectively; platelet between pair of presternal shields absent in Rykellus brevipellitus Karg & Schorlemmer, 2009 and Rykellus ovalis Karg & Schorlemmer, 2013 . Setae J 2, J 3 and J 4 at least as long as distance between their bases and bases of respective subsequent setae of J series in Rykellus ubatubaensis ( Hirschmann, 1966) and Rykellus longopilus ( Karg, 1976) .

Figures

FIGURES 1 – 8. Rykellus anibali n. sp. Female. 1. Antiaxial view of chelicera; 2. Apotele; 3. Palp genu; 4. Epistome; 5. Hypostome; 6. Dorsal idiosoma; 7. Ventral idiosoma; 8. Tritosternum. Lyrifissures and pores enlarged for improved visibility.

FIGURES 9 – 11. Rykellus anibali n. sp. Male. 9. Antiaxial view of chelicera; 10. Ventral idiosoma; 11. Anterolateral view of femur, genu and tibia of leg II. Lyrifissures and pores enlarged for improved visibility.