Macrocheles embersoni Azevedo, Castilho & Berto

Azevedo, Letícia H., Castilho, Raphael C., Berto, Marielle M. & De Moraes, Gilberto J., 2017, Macrochelid mites (Mesostigmata: Macrochelidae) from São Paulo state, Brazil, with description of a new species of Macrocheles, Zootaxa 4269 (3), pp. 413-426 : 416-418

Macrocheles embersoni Azevedo, Castilho & Berto , n. sp.

Adult female ( Fig. 2–11 ). Five specimens measured.

Gnathosoma. Fixed cheliceral digit 105 (100–110) long, with three teeth in addition to apical tooth and a setiform pilus dentilis ( Fig. 2 ); movable digit 92 (90–95) long, with three teeth in addition to apical tooth; antiaxial and dorsal lyrifissures as well as dorsal seta distinct. Arthrodial process of chelicera double brush-shaped. Numbers of setae on palp trochanter, femur and genu 2–5–6; all setiform; apotele three-tined. Epistome with a distally bifurcate anteromedian extension flanked by a pair of shorter distally expanded anterolateral extensions ( Fig. 3 ). Hypostome microtuberculate; deutosternum with six roughly transverse lines, the most distal smooth, others multidenticulate ( Fig. 4 ). Internal malae fused, with external margin fimbriate. Corniculus horn-shaped, about twice as long as its basal width. Seta h 3 about in longitudinal line with h 1, mesad of and slightly anteriad of h 2. Measurements of setae: h 1 68 (60–73), h 2 36 (28–43), h 3 95 (88–100), sc 37 (33–43); all aciculate and smooth.

Dorsal idiosoma ( Fig. 5 ). Idiosoma 900 (870–950) long and 600 (570–650) wide at widest level. Dorsal shield reticulate (except in central region of podonotal region, smooth) and punctate; 815 (735–830) long and 520 (483– 542) wide at level of coxa III, attenuate posteriorly; with 28 pairs of setae (j 1– j 6, z 1, z 2, z 5, z 6, s 2– s 6, r 2– r 4, J 2, J 5, Z 1, Z 3– Z 5, S 1, S 2, S 4 and S 5) and 22 pairs of distinguishable pores; with a cell-like depression (cj 3) between j 2 and j 3; with procurved line well developed posteriad of j 6, z 6, s 5 and r 4; with a posterior depression encompassing pore pZ5 and insertions of J5 and Z 5. Unsclerotised cuticle laterad of dorsal shield with nine pairs of setae (r 5, r 6, R 1–6 and R x). Measurements of setae: j 1 44 (41–48); j 2 57 (50–65); j 3 63 (58–64); j 4 65 (60–70); j 5 67 (63–70); j 6 43 (38–48); z 1 19 (14–25); z 2 65 (57–70); z 5 42 (39–45); z 6 51 (45–55); s 2 53 (47–60); s 3 64 (58–67); s 4 71 (62– 75); s 5 66 (60–75); s 6 65 (55–72); r 2 62 (57–67); r 3 63 (57–67); r 4 58 (51–65); r 5 30 (20–35); r 6 27 (25–30); J 2 45 (40–50); J 5 29 (21–33); Z 1 67 (60–75); Z 3 61 (50–65); Z 4 60 (50–65); Z 5 59 (51–67); S 1 53 (50–57); S 2 61 (52–70); S 4 68 (57–75); S 5 67 (59–76); R 1 29 (25–35); R 2 33 (28–40); R 3 38 (33–43); R 4 38 (33–43); R 5 43 (38– 45); R6 48 (43–55); R x 53 (48–55). All setae distinctly pilose distally ( Fig. 6 ), r 6 aciculate and smooth; j 1 stouter than other setae and with remote insertions.

Ventral idiosoma ( Fig. 7 ). Base of tritosternum 54 (43–65) long and 24 (23–25) wide proximally; laciniae 117 (95–133) long, pilose ( Fig. 8 ). Sternal shield with micropunctations and lines l. m. t., l. o. a. and l. o. p.; a. p. p. absent; 123 (120–125) long and 170 (162–183) wide at level of coxae II; with three pairs of setae and two pairs of lyrifissures. Seta st 4 and associated lyrifissure on metasternal platelet. Epigynal shield with micropunctations; 149 (138–155) long and 147 (133–158) wide at widest level, posterior margin straight; with a pair of accessory sclerites and with a pair of epigynal setae (st 5). Ventrianal shield with micropunctations and semiconcentric lines; 245 (220– 262) long and 187 (165–203) wide at widest level; with three pairs of pre-anal setae (Jv 1, Jv 2 and Jv 3) in addition to circum-anal setae; without distinguishable pores. Opisthogastric unsclerotised cuticle with seven pairs of setae (Jv 4, Jv 5 and Zv 1- Zv5). Peritreme extending anteriorly almost to level of z 1; with two pairs of lyrifissures (at level of posterior margin of coxa III and at level of coxa I) ( Fig. 9 ). Peritrematic shield restricted to the length of peritreme, fused to dorsal shield at level of z 4; with one pair of pores next to posterior tip of peritreme and one pair of pores at level of median region of coxa II; one pair of lyrifissures at level of posterior margin of coxa III. Cribral glands tuberculate and easily discernible at the cribral margins. Measurements of setae: st 1 56 (50–60); st 2 56 (50– 58); st 3 53 (47–58); st 4 45 (43–50); st 5 44 (43–48); Jv 1 39 (33–42); Jv 2 38 (30–42); Jv 3 33 (30–38); Jv 4 33 (30– 35); Jv 5 32 (30–35); Zv 1 30 (23–38); Zv 2 33 (28–35); Zv 3 33 (28–35); Zv 4 34 (28–38); Zv 5 46 (40–55); para-anal 37 (35–40); post-anal 11 (10–13). All ventral idiosomal setae aciculate and smooth.

Spermathecal apparatus ( Fig. 10 ). Similar to that of Macrocheles robustulus Berlese , illustrated by Costa (1966). Solenostome apparently opening at posteromedian margin of base of coxa III; infundibulum discreet. Sacculus foeminus consisting of two globular structures connected by a broad passage; tubulus annulatus meeting each globular structure via cone-shaped ramus sacculus; cornu sacculus thick-walled at region near sacculus foeminus, continuing as a narrow duct that flares distally into a rugose structure.

Legs. Length of legs (except ambulacrum): I, 620 (600–650); II, 654 (560–750); III, 676 (630–720); and IV, 1000 (920–1060). Chaetotaxy (coxa–tibia), I: 0 0/2 0/0 0, 1 0/1 1/1 1, 1 3/2 2/3 2, 3 2/2 1/1 2, 3 2/2 1/2 2; II: 0 0/1 0/1 0, 1 0/1 0/2 1, 2 3/1 2/2 1, 2 3/1 2/1 2, 2 2/1 2/1 2; III: 0 0/1 0/1 0, 1 1/2 0/0 1, 1 3/1 0/0 1, 1 2/1 2/0 1, 1 2/1 1/1 1; IV: 0 0/1 0/0 0, 1 1/2 0/1 0, 1 2/1 1/0 1, 1 2/1 1/0 1 ( Fig. 11 ), 1 2/1 1/1 1. Tarsi II–IV with 18 setae each. Tarsus I without ambulacrum and claw; tarsi II–IV with well developed ambulacra and claws.

Material examined. Holotype female and four paratype females from accumulations of dung at “Fazenda Paraíso” (22°27’20’’S; 49°20’15’’W), Cabrália Paulista , São Paulo state, Brazil, 24 March 2014. All types collected by L.H. Azevedo and deposited at Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “ Luiz de Queiroz ” ( ESALQ), Universidade de São Paulo ( USP), Piracicaba, São Paulo state, Brazil .

Etymology. The specific name embersoni is in honour of Dr. Rowan Mark Emberson, Lincoln University, Canterbury, New Zealand, for his extensive contributions to the taxonomy of Macrochelidae .

Remarks. Macrocheles embersoni is similar to species of the woodruffi cluster of the dimidiatus complex of the dimidiatus species group ( Krantz, 2007), mainly by having the dorsal shield attenuated posteriorly and with procurved line; j l pectinate and stouter than j 2; and ventrianal shield very small, with transverse section of anterior margin shorter than posterior margin of epigynal shield, with rounded anterolateral corners. Macrocheles embersoni is similar to Macrocheles spickai Krantz & Whitaker, 1988 but females of the latter species have unsclerotised cuticle laterad of dorsal shield with 10 pairs of setae (r 5– r 6, R 1–6 and two R x), sternal shield with l. ang. and a. p. p. present, and ventral idiosomal setae pilose distally.

The species of this group are a strongly cohesive assemblage not only morphologically, but also geographically and behaviourally. Members of the group are confined to the New World, with the vast majority of species being found in the neotropics ( Krantz, 2007).

Figures

FIGURES 2 – 6. Macrocheles embersoni n. sp. Female. 2. Lateral (antiaxial) view of chelicera; 3. Epistome; 4. Hypostome; 5. Dorsal idiosoma; 6. Seta j 5.

FIGURES 7 – 11. Macrocheles embersoni n. sp. Female. 7. Ventral Idiosoma; 8. Tritosternum; 9. Peritreme; 10. Spermathecal apparatus; 11. Genu of leg IV.