Myrmozercon hunteri, Joharchi, Omid, Babaeian, Esmaeil & Seeman, Owen D., 2015

Joharchi, Omid, Babaeian, Esmaeil & Seeman, Owen D., 2015, Review of the genus Myrmozercon Berlese (Acari: Laelapidae), with description of a new species from Iran, Zootaxa 3955 (4), pp. 549-560 : 550-551

Myrmozercon hunteri sp. nov.

( Figs 1–10 )

Specimens examined. Holotype, female, Iran, Alborz province, Savojbolagh, Khoznan, 36˚71' N, 50˚32' E, alt. 1595 m, 15 August 2013, O. Joharchi coll., clinging to the abdomen of soldiers of Myrmica sp. ( Formicidae ) (in JAZM). Paratype, one female, same data as holotype (in YIAU). (Host ants are also in YIAU).

Diagnosis. Dorsal shield reticulate, with 27–33 pairs setae, length 83–103; some dorsocentral setae in j -J series lacking; posterior margin of shield rounded, not truncated; soft cuticle posterior to shield hypertrichous. Sternal shield essentially normal, posterior margin eroded slightly; setae st4 present; genital shield elongate, reticulate, bearing setae st5 only; metapodal shields absent; anal shield triangular, without anterolateral extensions. Palp setal count (trochanter to tibia) 1-5-6-12; subcapitular groove with 11 rows of denticles, with 10–15 denticles per row; palp coxal seta present. Chelicerae with movable digit membranous, edentate, and fixed digit reduced, thin, edentate. Legs long, leg I longer (1280–1283) than all other legs (leg II 711–720; leg III 975–994; leg IV 1100– 1114); setal counts (coxa to tibia) for legs I–IV: 2-5-14-13-10, 2-5-11-11-10, 2-5-7-11 -10, 1 -5-7-11-10; many leg setae spatulate.

Description. Female. Dorsal idiosoma ( Fig. 1 ). Length 890 (900), width 830 (835). Dorsal shield length 840 (846), width 703 (710), broadly oval, reticulate; shield tapers gradually to a broad point, not covering entire idiosoma, leaving unsclerotised cuticle surrounding dorsal shield; dorsal shield with at least 27 pairs of setae (lateral margins capturing six additional setae on left-hand side in holotype), setae long (83–103), almost all setae distinctly serrate in apical third, except j1, z1 smooth. Pronotal part of dorsal shield holotrichous or slightly hypotrichous, setae in z - and s -series displaced laterally or lacking; opisthonotal part of dorsal shield hypotrichous, lacking anterior J -setae, setae in Z and S series lacking or displaced laterally; soft cuticle of opisthosoma hypertrichous. Muscle insertions prominent as desclerotised circular patches. Shield with 11 pairs of pore-like structures; lyrifissures near base of j1 large and slit-like.

Ventral idiosoma ( Fig. 2 ). Tritosternum with short, broad, free base 30 (32) long and paired smooth, strap-like laciniae 152 (155) long ( Fig. 2 ). Pre-sternal shields absent. Sternal shield length 149 (153), narrowest between coxae II 195 (198), widest between coxae II and III 343 (347), with biconvex anterior margin; posterior margin irregularly concave; shield bearing three pairs of small pointed setae (st1 16, st2 15, st3 15) and two pairs of lyrifissures, lyrifissures iv1 adjacent to setae st1, lyrifissures iv2 between st2 and st3; surface with indistinct linear ornamentation and weak transverse lines near anterior margin, central area smooth. Metasternal platelets absent, metasternal setae st4 16 (17) and metasternal pores iv3 located in soft cuticle; endopodal plates II/III fused to sternal shield, endopodal plates III/IV elongate, narrow, and free. Genital shield broad, rounded posteriorly, extending almost to anal shield; surface reticulate; genital setae st5 14 (15) (right side on soft skin in holotype); length 398 (408), maximum width 250 (257) at level of setae st5; shield flanked by two pairs of irregular platelets. Paragenital pores absent. Anal shield subtriangular, length 92 (98), width 164 (173), its anterior half with lineate ornamentation; bearing longer post-anal seta 58 (60), and a pair of para-anal setae 48 (50); all anal setae blunt, thickened. Anal pores absent, cribrum a narrow band without discernible rows. Opisthogastric cuticle hypertrichous, anal shield flanked by a pair of long narrow platelets 74 (79), all pores absent. Peritreme short, extending from coxa IV to anterior margin of coxa III. Lyrifissure near stigmata and post-stigmatal plate and pores absent.

Gnathosoma . Subcapitular groove with 14 rows of denticles, 10 to 15 very fine denticles per row, denticles more distinct in central rows and indistinct in anterior and posterior rows ( Fig. 3 ). Hypostome with three pairs of setae, internal posterior hypostomal setae h3 longest; surface of subcapitulum ornamented with transverse and curved lines ( Fig. 3 ). Palp coxal setae two-tined. Epistome triangular, smooth, with pointed apex ( Fig. 4 ). Palp setal counts: trochanter 1, femur 5, genu 6, tibia 12; all palp setae pointed; palp apotele two-tined ( Fig. 5 ), dorsodistal edge of palp femur with low swelling. Chelicera hyaline, fixed digit of chelicera reduced and edentate, pilus dentilis absent, cheliceral seta fine, prostrate ( Fig. 6 ); movable digit edentate, arthrodial membrane with a rounded flap and a few short filaments ( Fig. 6 ). Corniculi short, broad, weakly sclerotised. Internal malae separate (pushed to left side on illustration), fine and pointed, smooth, although paratype with few denticles. Lateral malae arms absent ( Fig. 3 ).

Legs. Legs ( Figs 7–10 ). Length of leg I 1280 (1283), leg II 711 (720), leg III 975 (994), leg IV 1100 (1114). Setal counts for legs I–IV (coxa to tibia): 2-5-14-13-10, 2-5-11-11-10, 2-5-7-11 -10, 1 -5-8-11-10. Chaetotaxy (both sides examined): Leg I: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 2 3/2 3/2 2, genu 2 3/2 3/1 2, tibia 2 2/2 1/1 2 ( Figure. 7 ). Leg II: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 2 3/1 2/2 1, genu 2 2/1 3/1 2, tibia 2 2/1 2/1 2 ( Fig. 8 ). Leg III: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 2 2/0 1/1 1, genu 2 3/1 2/1 2, tibia 2 3/1 1/1 2 ( Fig. 9 ). Leg IV: coxa 0 0/1 0/0 0, trochanter 1 0/1 0/2 1, femur 1 2/2 2/1 0, genu 2 2/1 3/1 2, tibia 2 1/1 3/1 2; almost all setae with club-like tip. Tarsi II-IV with 18 setae 3 3/2 3/2 3 + mv, md. All pre-tarsi with a pair of thin claws and a membranous ambulacrum.

Etymology. This species is named in honour of Preston E. Hunter, who did important early work on these mites.

Notes. The new species is unique within Myrmozercon because of its numerous club-tipped leg setae and its leg setal count, especially leg I. Leg setation varies considerably within the genus, but if femur and genu I have 13– 16 setae, then tibia I usually has 13–16 setae. The new species has 14 and 13 setae on femur and genu I, respectively, but only 10 setae on tibia I. The only species that shares a similar leg setal count is M. iainkayi which has 13 and 12 setae on femur and genu I, respectively, but 10 setae on tibia I.

The presence of 14 setae on tibia I is only known in three other species: Myrmozercon burwelli Shaw & Seeman, 2009 , M. flexuosa ( Michael, 1891) and some specimens of M. rotundiscutum Rosario & Hunter, 1988 , which has 13 or 14 setae. However, these are not the same setae, emphasising the importance of providing full setation. In M. burwelli and M. flexuosa , these species have two pd and three pv setae (i.e. 2 3/2 2/3 2) while M. rotundiscutum and the new species has three pd and two pv setae (i.e. 2 3/2 3/2 2).

In all other features the new species is closest to M. rotundiscutum in having very long legs I, lacking some of the J -series setae, being hypertrichous around the idiosomal margins, sharing a similar-shaped genital shield, and a similar body size. It is distinguished from this species by its palp and leg setal counts, simple palp coxal seta, and acuminate leg setae.

Figures

FIGURES 1 – 2. Myrmozercon hunteri sp. nov., female. 1. Dorsal idiosoma; 2. Ventral idiosoma.

FIGURES 3 – 6. Myrmozercon hunteri sp. nov., female. 3. Subcapitulum (im: internal malae); 4. Epistome; 5. Palp; 6. Chelicera.

FIGURES 7 – 10. Myrmozercon hunteri sp. nov., female. 7. Leg I; 8. Leg II; 9. Leg III; 10. Leg IV, dorsal aspect.