Epicriopsis atuberculatus, Narita, João Paulo Z. & De Moraes, Gilberto J., 2016

Narita, João Paulo Z. & De Moraes, Gilberto J., 2016, A new species of Epicriopsis Berlese (Acari: Mesostigmata: Ameroseiidae) from Brazil, with a key to the world species of the genus, Zootaxa 4114 (4), pp. 477-484 : 478-482

Epicriopsis atuberculatus n. sp.

Diagnosis. Membranous lobes attached to fixed and movable cheliceral digits. Anterior margin of epistome subtriangular and serrate. Dorsal shield without tubercles, but with rows of spine-like structures in the central region (a pair diverging posteriorly from base of j2 to base of z4; a pair converging posteriorly from a pore posterolaterad of j4 to base of j5; a subtriangular row between bases of j6 and J2; a transverse row running between setae Z3); bearing 25 pairs of setae in adult females and 27 pairs in adult males. Setae st3 on platelets and st4 on unsclerotised cuticle. Opisthogaster with six pairs of setae in addition to circumanal setae, all of which on unsclerotised cuticle; Jv5 stout and serrate.

Adult female ( Figs 1–6 ) (5 specimens measured).

Gnathosoma: Fixed cheliceral digit 20 (18–20) long, with three large median teeth and a large membranous lobe; dorsal and antiaxial lyrifissures distinct; movable digit 17 (15–17) long, with a median tooth and a large membranous lobe ( Fig. 1 ). Palp apotele bifid. Anterior margin of epistome subtriangular and serrate; with transverse row of denticles near the base ( Fig. 2 ). Corniculi undivided, each apparently overlaying a membranous, elongate and distally rounded structure extending slightly beyond the corniculus tip. Deutosternum with lateral delimiting lines subparallel for most of their length, separated from each other only near posterior end; with nine transverse lines, the three most anterior with 1–3 denticles each and the others without denticles. A pair of rows of denticles present behind sc, converging posteriorly to meet lateral deutosternal lines ( Fig. 3 ). Hypostomal and subcoxal setae aciculate. Setal lengths: h1 17, h2 17, h3 17, sc 18 (17–18).

Dorsal idiosoma: Dorsal shield entire ( Fig. 4 ), without tubercles, but with rows of spine-like structures in the central region (a pair diverging posteriorly, from base of j2 to base of z4; a pair converging posteriorly from a pore posterolaterad of j4 to base of j5; a subtriangular row between bases of j6 and J2; a transverse row running between setae Z3); 297 (288–300) long and 247 (240–250) wide at level of s6; apparently with six pairs of pores (laterad of j3, posterolaterad of j4, anterolaterad of j5, anteriad of Z1, posteromediad of Z1, posteromediad of S5) and seven pairs of lyrifissures (anterolaterad of j1, mediad of S2, posteriad of S2, laterad of S3, anterolaterad of J4, two pairs anterolaterad of S5). Podonotal region of dorsal shield bearing 15 pairs of setae (j1–j6, z2, z4–z6, s2–s6); opisthonotal region of dorsal shield bearing ten pairs of setae (J2, J4, Z1, Z3–Z5, S1–S3, S5). Setal lengths: j1 43 (38–50), j2 26 (25–30), j3 31 (25–38), j4 298 (288–313), j5 53 (50–63), j6 269 (258–275), J2 241 (225–275), J4 61 (58–65), z2 36 (30–43), z4 179 (175–180), z5 217 (200–230), z6 40 (38–43), Z1 227 (225–230), Z3 219 (215–220), Z4 63 (58–70), Z5 198 (188–208), s2 38 (30–45), s3 176 (163–200), s4 3 7 (30–43), s5 29 (25–30), s6 32 (25–45), S1 42 (40–45), S2 46 (42–50), S3 37 (33–40), S5 105 (100–113). Dorsal shield setae at least as long as distance to the subsequent setae of the same series, except j2 and S3; all dorsal shield setae stout and serrate.

Ventral idiosoma ( Fig. 5 ): Base of tritosternum 12 (10–12) long and 24 (20–25) wide, laciniae fused for about one-third of their total length [44 (38–50)]. Sternal shield ornamented with a few lines, 35 (30–42) long at midline and 80 (75–87) wide at the widest level, with lateral projections between coxae I and II, concave posteriorly, bearing st1 and st2. Setae st3 on separate platelets, st4 on unsclerotised cuticle. Lyrifissures iv1–iv3 not discernible. Region between platelets bearing st3 and anterior edge of genital shield with light sclerotisation. Genital shield smooth, except for a pair of posteriorly divergent lines, 85 (82–87) long including anterior hyaline flap, 67 (63–75) wide at widest level, bearing st5. With a pair of pores (gv2, according to interpretation of Narita et al., 2013a) anteriad of a pair of lyrifissures (iv5), both on unsclerotised cuticle next to posterior corners of genital shield. Anal shield ovate, ornamented with scant curved lines, 81 (70–87) long and 102 (100–112) wide; anal opening 34 (28– 37) long and 25 (23–25) wide. Unsclerotised cuticle around anal shield with six pairs of opisthogastric setae (Jv1– Jv5 and Zv2) and five pairs of lyrifissures (three pairs laterad of Jv3 and Zv2, posterolaterad of Jv4 and mediad of Jv5). Setal lengths: st1 27 (25–30), st2 28 (25–32), st3 28 (25–32), st4 20 (15–22), st5 20 (17–22), Jv1 12, Jv2 12, Jv3 12, Jv4 18 (15–20), Jv5 110 (107–112), Zv2 12, para-anal 15 (13–17), post-anal 17 (13–22). Seta Jv4 serrate, Jv5 stout and serrate, other ventral idiosomal setae aciculate and smooth. Endopodal and exopodal plates not discernible.

Peritreme and peritrematic shield: Peritreme extending anteriorly slightly beyond z2 ( Fig. 4 ); peritrematic shield narrow, fused to dorsal shield at level of j2, with a large pore at level of coxa III (gd3 of Athias-Henriot, 1975; gp2 of Lindquist & Moraza, 2009), a pore and two lyrifissures behind stigma ( Fig. 6 ).

Legs: Pretarsi of legs I-IV each consisting of an elongate stalk, a pair of claws and pulvillus with three rounded lobes. Leg lengths: I: 388 (345–420); II: 291 (265–310); III: 312 (305–320); IV: 382 (345–405). Chaetotaxy of legs I–IV: coxae: 2, 2, 2, 1; trochanters: 6 (1 0 1/3 1), 5 (1 0 0/3 1), 5 (1 1 0/3 0), 5 (1 1 0/3 0); femora: 11 (2 3/1 2/2 2), 10 (2 2/1 2/2 1), 6 (1 2/1 1/0 1), 6 (1 2/1 1/0 1); genua: 12 (2 3/2 2/1 2), 10 (2 3/1 2/0 2), 8 (2 2/1 3/0 1), 9 (2 2/1 3/ 0 1); tibiae: 12 (2 3/2 2/1 2), 10 (2 2/1 2/1 2), 8 (2 1/1 2/1 1), 9 (2 2/1 2/1 1); tarsi II–IV: 17, 17, 17. Dorsal setae of femur, genu and tibia of legs I-IV serrate, other leg setae smooth. Ventral surface of each coxa with 1–3 lines of denticles.

Adult male ( Figs 7–10 ) (two specimens measured).

Gnathosoma: Fixed cheliceral digit 20 (19–20) long, with a large subterminal tooth; dorsal and antiaxial lyrifissures not discernible; movable digit 15 long, with two teeth near apex ( Fig. 7 ). Spermadactyl 20 long, wider distally, nearly straight. Epistome, palp apotele, corniculi and deutosternum similar to adult female. Setal lengths: h1 15, h2 17, h3 15, sc 15.

Dorsal idiosoma: Dorsal shield entire ( Fig. 8 ), without tubercles, but with rows of spine-like structures in the central region (a pair running transversely between bases of j4 and z3, a pair running about longitudinally from a point posteriad of j4 to base of j6; a subtriangular row between bases of j6 and J2); 235 long and 215 wide at level of s6; apparently with two pairs of pores (between j3 and z3 and mesad of Z1) and six pairs of lyrifissures (anterolaterad of j1, anterolaterad of j3, mediad of Z1, anteriad of J2, posteromediad of S1 and mediad of S2). Podonotal region of dorsal shield bearing 18 pairs of setae (j1–j6, z2–z6, s1–s3, s5, s6, r2, r3); opisthonotal region of dorsal shield bearing nine pairs of setae (J2, J4, Z1, Z3–Z5, S1, S2, S5). Lengths of dorsal setae: j1 41 (40–42), j2 21 (20–22), j3 20, j4 270, j5 31 (30–32), j6 211 (210–212), J2 198 (190–205), J4 37 (33–40), z2 30, z3 164 (160– 167), z4 165 (160–170), z5 150, z6 24 (23–25), Z1 180, Z3 178 (175–180), Z4 37 (33–40), Z5 158 (155–160), s1 162 (160–163), s2 28 (25–30), s3 25, s5 25, s6 25, S1 34 (33–35), S2 29 (27–30), S5 73 (70–76), r2 26 (25–27), r3 25 (22–27). Dorsal shield setae at least as long as distance to the subsequent setae of the same series, except j2, Z4, s5, s6 and r2; all dorsal shield setae stout and serrate.

Ventral idiosoma ( Figs. 9, 10 ): Base of tritosternum 5 long and 15 wide, laciniae fused for about 30% of their total length [25 (22–27)]. Sternogenital shield smooth, 108 long and 70 wide at the widest level, bearing st1–st3 and st5; st4 on unsclerotised cuticle. Ventrianal shield with striae about transverse anteriad of anal opening and diagonal laterad of anal opening, 60 long and 90 wide, concave anteriorly and with a pronounced notch behind post-anal seta, bearing Jv2, Jv3, Zv2 and circumanal setae; with a pair of marginal pore posterolaterad of para-anal setae; anal opening 26 (23–29) long, 15 wide. Unsclerotised cuticle around ventrianal shield with Jv1 and Jv5, and three pairs of lyrifissures (anaterolaterad, anteromediad and posterolaterad of Jv5). Setal lengths: st1 21 (20–21), st2 18 (15–20), st3 16 (14–18), st4 16 (14–17), st5 15, Jv1 12, Jv2 12, Jv3 11, Jv5 27, Zv2 11, para-anal 16 (15–17), post-anal 16 (15–17); Jv5 stout and serrate, other ventral idiosomal setae aciculate and smooth. Endopodal and exopodal plates not discernible.

Peritreme and peritrematic shield: Similar to adult female.

Legs: Chaetotaxy of legs similar to adult females. Leg lengths: I: 343 (330–355); II: 270 (260–280); III: 258 (250–265); IV: 313 (290–335).

Type specimens. Holotype female, six paratype females and two paratype males collected between 11 August 2014 and 8 October 2014. All specimens collected by R.V.S. Veloso, from leaves of macaúba palms [ Acrocomia aculeata (Jacq.) Lodd. ex Mart. ; Arecaceae ] from a patch of Atlantic Forest (20º28’39”S, 43º52’07”W) at Congonhas, Minas Gerais state, Brazil. Deposited at Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, São Paulo state, Brazil.

Additional specimens examined. The authors also examined the following specimens of E. atuberculatus n. sp.: (a) Two adult females and one adult male previously reported by Marticorena & Berrío (2014) as a new species of Epicriopsis , and an adult female collected by S.J. Jorge (Procitrus, Peru), from avocado leaves collected in Peru; (b) Two adult females and one adult male from coffee and Matisia cordata Humb. & Bompl. (Malvaceae) leaves collected in Colombia.

Etymology. The specific name atuberculatus refers to the absence of tubercles on dorsal shield.

Remarks. Females and males of E. atuberculatus differ from all other Epicriopsis species in the following way: absence of tubercles on dorsal shield; presence of rows of spine-like structures in the central region of the dorsal shield; adult females with 25 pairs and adult males with 27 pairs of dorsal shield setae (21 pairs in males of E. mirabilis Willmann, 1956 and 19 pairs in males of E. palustris Karg, 1971a and E. rivus Karg, 1971b ). This is the first species of this genus described from the American continent.

Cheliceral membranous lobes have been shown in the description of most Epicriopsis species. In addition to the new species here described, cheliceral lobes have been shown in the original descriptions ( Karg, 1971a, Karg, 1971b; Ishikawa, 1972; Livshitz & Mitrofanov, 1975; Kandil, 1978; Halliday, 1997; Ma, 2002) or redescriptions ( Bregetova, 1977) of E. baloghi Kandil , E. horridus ( Kramer, 1876) , E. hungarica Kandil , E. jilinensis Ma , E. langei Livshitz & Mitrofanov , E. palustris Karg, 1971a , E. stellata Ishikawa, E. suedus Karg, 1971b and E. walteri Halliday. Nothing was mentioned in this regard in the description or redescriptions of E. mirabilis Willmann, 1956 and E. rivus Karg, 1971b . However, differences concerning the cheliceral digit to which these structures are attached seem to occur, according to the literature. In E. walteri , a membranous lobe is shown attached to the fixed digit; in E. baloghi , E. hungarica , E. jilinensis and E. suedus it is shown attached to the movable digit, while in E. atuberculatus n. sp., E. langei and E. stellata (apparently also in E. horridus and E. palustris ) membranous lobes are shown attached to both cheliceral digits. It is not known whether the lobes on the distinct digits are homologous.

The rounded lobes of the new species here described seem different in shape from those in most other Epicriopsis species – distally pointed or slightly rounded. Variation in lobe shape have also been observed among species of other ameroseiid genera, including the pollen feeding Afrocypholaelaps , Hattena and Neocypholaelaps ( Elsen, 1972a; Elsen 1972b; Halliday, 1997; Narita et al., 2011; Narita et al., 2013a). In part, the difference could be due to the fact that the lobes are not sclerotised ( Narita et al., 2013a). Evans (1963) suggested the Epicriopsis species to be fungivorous. The presence of spores of undetermined fungi adherent to the idiosoma of the new species here described supports that assumption. A correlation between the presence or absence of cheliceral lobes, and their shape, with feeding habits does not seem straightforward, as discussed by Narita et al. (2013a).

Lobes attached to both digits apparently have not been mentioned or illustrated in other ameroseiid genera; in those, lobes have apparently not been reported attached to the movable digit.

Figures

FIGURES 1 – 6. Epicriopsis atuberculatus n. sp. female. 1. Chelicera; 2. Epistome; 3. Ventral view of gnathosoma; 4. Dorsum of idiosoma; 5. Venter of idiosoma; 6. Proximal section of peritreme and associated structures (a: unsclerotised cuticle; b: peritrematic shield). Pores and lyrifissures enlarged to allow their differentiation.

FIGURES 7 – 10. Epicriopsis atuberculatus n. sp. male. 7. Chelicera; 8. Dorsum of idiosoma; 9 and 10. Venter of idiosoma of two paratypes. Pores and lyrifissures enlarged to allow their differentiation.