Blaszakzercon hexagonatus, Ujvári, 2012

Ujvári, Zs., 2012, Review Of The American Genera Aspar Halašková, 1977 And Blaszakzercon Kemal & Koçak, 2009 (Acari, Mesostigmata, Zerconidae) With Description Of Three New Species, Acta Zoologica Academiae Scientiarum Hungaricae 58 (3), pp. 275-296 : 284-288

Blaszakzercon hexagonatus sp. n.

( Figs 21–31 , 42 )

Type material. Female holotype, four female, one male and one deutonymph paratypes: USA, Tennessee, Blount County, Cades cove, 30.07.1956, coll. K. BOHNSACK (É-Am-013); 25 female paratypes: USA, Tennessee, Great Smoky Mountains National Park , 4000 ft. a.s.l., 28.07.1956, coll. K. BOHNSACK (É-Am-033). ( Fig. 44 ). The holotype, each paratypes of É-Am–013 and 20 paratypes of É-Am-033 are deposited in HNHM , 5 female paratypes of É-Am-033 are deposited in CNC (coll. number of CNC specimens: CNCAZ0794–0798 ) .

Diagnosis. Central podonotal setae smooth and needle-like, marginal setae and j1–2 pilose. Setae J3–4 finely pilose, S2 smooth and pointed. Z3–4 delicately pilose, shorter than S3–5. Lateral posterodorsal cavities covered by strongly sclerotized lobes. Podonotum covered by a reticulation of circular squamae, central surface of opisthonotum with distinct, clover-shaped protuberances arranged in a hexagonal pattern.

Description. Female. Length of idiosoma: 350–366 µm (357 µm); width: 296–317 µm (305 µm) (n = 10).

Dorsal side ( Figs 21 , 25 ). Podonotum with 20 pairs of setae, j1–6, z2–6, s1–6, r2 and r4–5 inserted dorsally, r1 and r3 inserted ventrally, on peritrematal shields. Marginal setae of podonotum (s1–3, z2–3, r2, r4–5, s6) and j1–2 densely pilose, feathered. Setae j3–6, z4–6 and s4–5 smooth and needle-like. Glands gds1 (po1) situated on line connecting j3 and s1, near s1; gdj4 (po2) medially to z4; gds4 (po3) on line connecting s4 and s5, in equidistant position. Podonotum covered by a reticulation of circular squamae.

Opisthonotum ( Figs 26 , 42 ) with 22 pairs of setae, J1–5, Z1–5, S1–5, R1–7. Setae J1–2 smooth, pointed, J1 not reaching insertions of J2. J3–4 pointed, finely pilose, J5 smooth. Setae Z1–2 smooth and needle-like, none of them reaching bases of the following one in the series. Z3–4 delicately pilose, pointed, shorter than S3–5. S2 similar in appearance to Z1–2, situated laterally or somewhat posterolaterally to Z1. Setae S3–5 and Z5 elongate, densely pilose, feathered. Setae S1 and R1 three times longer than other R-setae, pilose. R2–5 short, pointed, barbed, R6–7 smooth, thorn-like. Length of opisthonotal setae and distances between their insertions as in Table 4. Glands gdZ1 (Po1) situated anteromedially to insertions of Z1; gdS2 (Po2) on line connecting Z2 and S2, closer to S2; gdZ3 (Po3) situated on line connecting J4 and Z3, near Z3; gdS5 (Po4) on line connecting S5 and Jv5, near Jv5. Marginal serration deep and obtuse. Central and lateral surface of opisthonotum bearing distinct, clover-shaped protuberances arranged in a hexagonal pattern ( Fig. 28 ). Dorsal cavities uniform, well-sclerotized. Lateral pair covered by strongly sclerotized lobes ( Fig. 27 ).

Ventral side ( Fig. 22 ). Shape of peritrematal shields and peritrematal setae typical for the genus. Posterolateral tips of peritrematal shield reaching beyond insertions of R2. Peritremes slightly bent, with a distinct dilatation near the stigma. Peritrematal shields covered by longitudinal lines. Sternal shield well sclerotized, 63 µm long and 42 µm wide at the level of setae st2, with straight posterior margin, its ornamentation not conspicuous. Adgenital glands gv2 with two openings, situated on small adgenital platelets. Ventrianal chaetotaxy incomplete, setae Zv1 absent. Preanal and adanal setae short, smooth and needle-like, postanal seta longer, smooth. Setae Jv5 elongate, pilose. Anal valves with vestigial euanal setae. Glands gv3 situated laterally to adanal setae. Anterior surface of ventrianal shield covered by squamous pattern.

Gnathosoma. Situation of hypostomal and subcapitular setae typical for the family. Setae h1–2 similar in appearance, elongate, needle-like. Setae h3 shorter than h1–2, needle-like, h4 somewhat longer than previous setae, serrate. Corniculi horn-like, internal malae with a pair of bifurcate anterocentral branches and with serrate margins. Chelicerae relatively slender, fixed digit with 6 teeth, movable digit with 4–5 teeth. Epistome ( Fig. 29 ) typical for the genus Blaszakzercon , of Zercon - type (see UJVÁRI 2011 b).

Male. Length of idiosoma: 300 µm; width: 251 µm (n = 1).

Dorsal side ( Fig. 23 ). Chaetotaxy, adenotaxy and ornamentation of dorsal shields similar to that of female, but some of the opisthonotal setae shorter in proportion to the body-length than in female. Length of opisthonotal setae and distances between their insertions as in Table 4. The characteristic posterodorsal lobes observed on females absent.

Ventral side ( Fig. 24 ). Posterolateral parts of peritrematal shields fused to ventrianal shield on level of setae R1, the separating membranous slit between ventral and dorsal shields absent. Shape of peritrematal setae as for the female. Peritremes slightly bent anteriorly, the dilatation near the stigma not conspicuous. Peritrematal shields covered by some longitudinal lines. Sternigenital shield possessing four pairs of setae (st5 absent). Anteriorly the genital opening the shield covered by reticulate ornamentation, beyond the level of setae st4 irregular ditches can be observed on its surface. The adgenital region not clearly visible. Setae Jv1 situated much closer to each other than in female. Other ventrianal characters similar to that of female.

Gnathosoma. Not clearly visible.

Deutonymph ( Fig. 31 ). Length of idiosoma: 290 µm; width: 239 µm (n = 1).

Dorsal side. Chaetotaxy and adenotaxy similar to that of the aduts, however some of the opisthonotal setae shorter in proportion to the body-length than in adult specimens. Length of opisthonotal setae and distances between their insertions as in Table 4. Anterior and lateral surface of podonotum covered by a reticulation of granulate pattern and undulate lines, ornamentation of the central surface weaky developed. Lateral surface of opisthonotum covered by a reticulation of granulate pattern, central surface around setae J3–4 with small protuberances. Dorsal cavities weakly sclerotized, the characteristic posterodorsal lobes observed on females absent.

Gnathosoma. Each characters similar to that of female. It is interesting to remark that deutonymphal epistome of each Zerconidae species studied before showed similar morphology, with four conspicuous, prolonged anterior processes, however deutonymphs of B. hexagonatus sp. n. possess characteristic, Zercon - type epistome ( Fig. 30 ).

Etymology. The name of the new species refers to the hexagonal pattern of clover-shaped protuberances covering the opisthonotum.

Remarks. Specimens from Great Smoky Mountains National Park possess less sclerotized posterodorsal lobes, fewer of posterolateral protuberances on dorsal surface and smooth Z3–4 setae ( Fig. 42 ).

Differential diagnosis. The two Blaszakzercon species can easily be distinguished by the following features: opisthonotal ornamentation (distinct, clover-shaped protuberances arranged in a hexagonal pattern in B. hexagonatus sp. n., distinct, alveolar pits arranged in a hexagonal pattern in B. pulcher ), posterodorsal lobes (smaller, laterally sclerotized in B. hexagonatus sp. nov., large, bean-like, completely sclerotized in B. pulcher ) and shape of Z3–4 (pointed and as long as Z 1–2 in B. hexagonatus sp. n., blunt and twice as long as Z 1–2 in B. pulcher ).

Figures

Fig 25. SEM photo of Blaszakzercon hexagonatus sp. n. female, in dorsal view (scale: 100 µm)

Fig 44. Occurrences of Aspar and Blaszakzercon species in North America

Figs 21–24. Blaszakzercon hexagonatus sp. n.: 21 = dorsal view of female, 22 = ventral view of female, 23 = dorsal view of male, 24 = ventral view of male (scales: 100 µm)

Figs 26–28. SEM photos of Blaszakzercon hexagonatus sp. n. female: 26 = opisthonotum, 27 = posterodorsal lobe, 28 = central ornamentation of opisthonotum (scales: 25 µm)

Figs 29–31. Blaszakzercon hexagonatus sp. n.: 29 = epistome of female, 30 = epistome of deutonymph, 31 = dorsal view of deutonymph (scales: a = 25 µm, b = 100 µm)

Figs 42–43. Blaszakzercon species: 42 = opisthonotum of B. hexagonatus sp. n. female, 43 = posterior part of opisthonotum of B. pulcher (BŁASZAK, 1984) female (scale: 100 µm)